Biodiversity and Conservation 5,607-647 (1996) Current and future threats to plant biodiversity on the Cape Peninsula, South Africa D.M. RICHARDSON*, B.W. van WILGEN?, S.I. HIGGINS, SMITHS, R.M. COWLING, and D.H. McKELLt *Institute for South Africa Plant Conservation, fCSIR Division of Forest Science Steilenbosch 7599, South Afn’ca $Bolus Herbarium, Botany Botany Department, & Technology, Department, University University Jonkershoek of Cape Forestry of Cape Town, Town, Research Rondebosch T.H. TRINDERRondebosch Centre, 7700, Private 7700, South Bag X 5011, Africa Received 25 May 1995; accepted 28 August 1995 The biodiversity of the Cape Peninsula (49127 ha in extent) has been considerably affected by various factors since European settlement in 1652. Urbanization and agriculture have transformed 37% of the original area of natural vegetation. Lowland vegetation types have been worst affected, with almost half of the transformation occurring in one of the 15 recognized vegetation types. Vegetation at high altitudes has been little affected by urbanization and agriculture, but alien trees and shrubs are now threatening biodiversity in these areas. Of the area not affected by urbanization and agriculture 10.7% is currently under dense stands (>25% canopy cover) of alien plants and another 32.9% is lightly invaded. Dense stands of Acacia cyclops, the most widespread invader, cover 2510 ha, 76% of the total area under dense alien stands. This paper assessesthe impacts of these factors on aspects of the plant biodiversity of the area, namely, the distribution of major vegetation types and of endemic, rare and threatened plant taxa and of taxa in the Proteaceae (a prominent element in almost all communities, taken as an indicator of overall plant biodiversity). Possible future impacts on biodiversity are assessedby considering the effects of several scenarios involving increased urbanization and changes to alien plant control strategies and further spread over the next 50-100 years. The worst-case scenario for urbanization sees the area under natural vegetation reduced to 12 163 ha (39.3% of its extent in 1994, or 24.8% of its original extent). Under this scenario almost a quarter of the 161 endemic, rare and threatened (‘special’) taxa are confined totally to urban areas; 57.4% of the known localities of these taxa, and 40.1% of the remaining localities of Proteaceae taxa are transformed. Dense alien stands currently affect 29.8% of the localities of special taxa known from herbarium records and 8.4% of these taxa currently occur only in areas at present affected by aliens. Clearing all dense stands would result in 62.9% of special taxa having lessthan half of their known localities affected (49.1% at present). Under this scenario, 92% of Proteaceae taxa have more than 75% of their localities unaffected by aliens. If clearing is confined to specific areas (the Cape Peninsula Protected Natural Environment or all publicly-owned land) and the aliens spread further outside these areas, the area of natural vegetation remaining shrinks (to 82.4% of the current extent if control is confined to public land). The further lossesin biodiversity associated with these scenarios are described. If control programmes collapse and all potentially invadable land is occupied by dense alien stands, only 407 ha of natural vegetation would remain (1.5% of the current extent). The probability of the various scenarios materializing is discussed.To minimize further lossesin biodiversity it is essential that: (1) a major initiative is launched immediately to clear (firstly) the *To whom correspondence should be addressed. 0960-3115 0 1996 Chapman & Hall 608 Richardson et al. 10 184 ha of lightty invaded vegetation and then the 3313 ha of densely invaded vegetation: (2) no urban development be permitted within the boundaries of the Cape Peninsula Protected Natural Environment; (3) a systematic programme of prescribed burning (linked to the alien control programme) is initiated; and (4) contingency measures are implemented to improve the status ol seriously threatened taxa. habitats and vegetation types. Biodiversity: biological invasions: Cape Floristic Region: GIS: landscape ecology. urbanization; fynbos. Keywords: Introduction Mediterranean-climate areas worldwide are currently the focus of human immigration and population expansion, making them disproportionately susceptible to environmental stress and degradation (Di Castri, 1994). This global pattern is reflected in the Western Cape Province of South Africa where there has been, and continues to be, massive immigration from elsewhere in southern Africa. The population of the Greater Cape Town area (sensu Bridgman et al., 1992) is currently about 3.2 million; with an annual increase of 5%, this will reach 4 million by the year 2000, and 10 million by 2019. The considerable biodiversity of the Cape Peninsula (Cowling et al., 1996, Trinder-Smith ef al.. 1996a; Simmons and Cowling, 1996) is severely threatened by various factors related to human pressure; 141 plant taxa in the area are currently classified as threatened according to IUCN criteria, with at least 39 having become extinct on the Cape Peninsula in the 20th century (Trinder-Smith et al., 1996a). and the threats are escalating rapidly. The Peninsula’s biodiversity is directly threatened by urbanization and other pressures. including agriculture and plantation forestry. Human settlement and the rapid growth of human populations has produced other threats to biodiversity, for example through the introduction and dissemination of invasive alien trees and shrubs, and possibly through alterations to the natural fire regime. There are other existing and potential threats in the area, including pollution, human recreational pressure, and the non-sustainable harvesting of natural plant products (Hall and Veldhuis. 1985). Agriculture has had a marked impact on biodiversity, but there is unlikely to be an appreciable expansion in this form of land-use on the Peninsula in the near future. Our analysis concentrates on the effects of urbanization and alien plants, as these are likely to be the major threats in the future. Urbanization and agriculture affect biodiversity directly through the physical destruction of habitats for plants and animals, and indirectly through fragmentation of habitats which disrupts important processes such as gene flow and the spread of fires. There are also many important ‘edge effects’ caused by the spill-over of human influences into remaining unmodified habitats (Moll et al., 1978). Alien trees and shrubs impact on biodiversity most obviously by replacing the indigenous vegetation, thereby supplanting native taxa (Richardson etal., 1989) and providing habitat for other alien organisms which may further disrupt natural processes (e.g. European starlings, Sturnus vulgaris, in stands of alien Acacia spp. which change seed dispersal patterns). Alien plants also cause many other less direct impacts on biodiversity, such as changed fire regimes and nutrient budgets (Richardson et al., 1992). Plant recruitment in fynbos is driven by fire, and modifications to the frequency, seasonal occurrence and intensity of fires has a marked influence on biodiversity (van Wilgen et al.. 1992), especially if these changes are concurrent with other threats. Threats to biodiversity on the Cape Peninsula 609 The threats to biodiversity on the Cape Peninsula, although widely appreciated (e.g., Moll et al., 1978; Hall and Ashton, 1983; Hall and Veldhuis, 1985; Hall, 1987; Macdonald et al., 1987; Wood et al., 1994), have not been documented in a systematic and quantitative way that facilitates the prediction of future impacts. This paper aims: (1) to assess these impacts of humans on plant biodiversity since European settlement in 1652; and (2) to provide an objective framework for predicting the impact of future developments on the biodiversity. In exploring the future of the region’s biodiversity we have constructed various scenarios that take account of the biological and socio-political factors that are likely to regulate the pressure on biodiversity in the area over the next 50-100 years. Approach and methods DEFINING BIODIVERSITY Biodiversity encompasses the heterogeneity that occurs at all levels in a region’s biota. It includes the variety of species of plants, animals and other organisms, and the genes they contain and the communities and ecosystems of which they form part. Patterns of biodiversity form a nested hierarchy, with genotypic variability forming the basis upon which diversity at the population, species, assemblage and ecosystem levels is built (Hobbs et al., 1995). Strategies for conserving biodiversity usually give priority to the preservation of endemic or threatened taxa and to rare and/or unique ecosystems (which presumably accommodate unique assemblages of biota). The elimination of populations of native plant species is a particularly serious threat in the fynbos where many taxa exist in small, isolated populations (4% of the native plant taxa on the Peninsula are endemic to the area, et al., 1996a). Less often and 6% of taxa are currently threatened; Trinder-Smith emphasized, but also very important, is the need to conserve populations of common taxa and widespread habitat types, since these house vital reservoirs of genetic diversity. Sound strategies for conserving biodiversity should therefore also make allowance for conserving portions of all representative community types and populations of widespread species. We have used this reasoning in deciding upon how to ‘measure’ biodiversity (and the extent of various threats to it) on the Cape Peninsula for the purposes of this study. But how does one arrive at a practical and yet meaningful ‘measure’ of biodiversity for an area such as the Cape Peninsula? We suggest that the extent and distribution of major vegetation types (defined and mapped on the basis of floristics, dominant taxa and structure; Cowling et al., 1996) provides a reasonable delineation of the major habitat types on the Cape Peninsula. Although defined solely on the basis of dominant plant growth forms, this delineation probably also provides a reasonable basis for classifying habitats for other taxa (Cowling et al., 1996) and therefore serves as a crude index for overall biodiversity. We created GIS (Geographic Information System) coverages of the distribution of 161 endemic and threatened plant taxa (species, sub-species and varieties; hereafter called ‘special taxa’), including 82 of the 90 endemic taxa (68 taxa in these categories were also classified as ‘rare’), and of 38 of the 45 native Proteaceae taxa for which detailed distribution data were available as descriptors of biodiversity (see Table 1 and Trinder-Smith etal., 1996b for further details of biodiversity in these vegetation types). The Proteaceae is a prominent and conspicuous family whose taxa range from common 610 Richardson el al. and widespread to rare, localized and threatened. Some Proteaceae are endemic to the Peninsula whereas others have ranges that extend across large parts of the fynbos biome (e.g. see Rourke, 1980 for Protea). We reasoned that a detailed assessment of the impacts of urbanization and alien plants on taxa in this family should provide a reasonable indication of the fate of the entire flora (see Rebel0 and Siegfried, 1990). The data from herbarium records (for ‘special taxa’) include many records from localities that have already been transformed by agriculture or urbanization. These records date back to 1854, with the approximate spread of collections as follows: 1854-1885 (5%); 1885-1910 (20%); 1910-1940 (30%); 1940-1975 (35%); 1975-1994 (10%). These data are therefore suitable for assessing the impacts of recent changes in the magnitude of the major threats to biodiversity. The data for Proteaceae from the Protea Atlas Project are much more recent (mostly 1990-1994); they reflect the distribution of species in the remaining vegetation and facilitate a more detailed assessment of future changes in biodiversity under various scenarios than is possible with the data for special taxa. Table 1. Data used to quantify biodiversity and the major threats to this biodiversity on the Cape Peninsula. The data were used to create Arc/Info coverages Description Source Vegetation types A classification of the vegetation based on floristics. structure and dominant taxa; extended by interpolation to cover the whole Peninsula (including areas now transformed) Mapped on 1:10 000 orthophotos (Cowling et al.. 1996) Distribution of endemic and threatened plant species and 38 speciesof Proteaceae Distribution data (at a resolution of 1 km2) for endemic and threatened taxa from over 22 000 herbarium records dating back to 18.54. Actual locality data from field record cards for 38 indigenous Proteaceae taxa Bolus Herbarium, Botany Department, UCT (TrinderSmith et al.. 1996a), and the Protea Atlas Project Urbanization The extent of urban areas, agricultural land, and natural vegetation (including invaded fynbos) LANDSAT thematic mapper image, October 1992. Land use was classified in 30 m x 30 m pixels Alien plant species Data are recorded for each species,divided into seven density classesbased on aerial cover (Le Maitre and Versfeld, 1994) Mapped during field surveys in 1994 on 1:lOOOO orthophotos Data layer Biodiversity Threats 611 Threats to biodiversity on the Cape Peninsula DEFINING TI-IE THREATS CAUSED BY URBANIZATION, ALIEN PLANT INVASIONS AGRICULTURE AND The major threats to biodiversity were assessed by surveying the extent of invasion by alien woody plants in various density classes and of various categories of land transformation (Table 1). For the purposes of this study we have assumed that alien trees and shrubs only affect plant biodiversity when their projected canopy cover exceeds 25% (‘dense stands’ in this paper); see Richardson et al. (1989) for justification. All mapped categories of transformation through agriculture and urbanization (Table 1) are considered to affect biodiversity since these usually involve total removal of the natural vegetation. The effects of urbanization and alien plants on the above-mentioned elements of biodiversity were assessed by overlaying coverages depicting threats on coverages containing the various biodiversity features using a GIS (ARC/INFO version 6.1.1.; Environmental Systems Research Institute, Redlands, California). To assessthe impact of various land-use categories on the vegetation it was necessary to extend the classification of extant vegetation (1994) to the whole Cape Peninsula (i.e. to determine what natural vegetation existed in areas where none remains at present). This was done by studying relationships between the existing natural vegetation and various physical features (notably soil features and topography), and interpolating to cover the whole area (see Cowling et al., 1996). SCENARIOS The above-mentioned data were used to assess the current status of plant biodiversity. To assess the impacts of changes in the extent and magnitude of the two major categories of threat, urbanization and alien plant invasions, we developed several scenarios based on socio-political and ecological factors. We first developed ‘profiles’ (sets of attributes describing the distribution and extent of urbanization and dense stands of alien plants) using coverages of altitude, slope and vegetation types. We defined the ‘urbanization profile’ for the Cape Peninsula in terms of slope and altitude (since development is limited by steep slopes and is unlikely at high altitudes where exposure and access are restrictive). Our ‘urbanization profile’, therefore, described conditions suitable for urbanization as those with slopes of less than 45 degrees and elevations of between 0.2 and 250 m above sea level. Exploratory analyses revealed that the distribution of alien plants was largely determined by soil type and altitude. Available data on the distribution of soil types were inadequate for modelling, and we used the delineation of vegetation types (which closely mirror major soil categories; Cowling et al., 1996) as the best available surrogate measure of the adherence of alien plants to particular habitats. These profiles were used to predict how urbanization and alien plants could spread by occupying currently untransformed areas with the same characteristics as those currently affected. These predictions on their own are simplistic as they make no allowance for socio-political realities. Factors that must be considered when defining scenarios for changing threats to biodiversity on the Cape Peninsula include the following: (1) The relaxation, in the early 1980s of rigid influx control regulations lead to the massive influx of impoverished people to the Western Cape. Most of these people now live in conditions of poverty and over-crowding on the resource-poor Cape Flats which adjoins the Cape Peninsula (see Bridgman et al., 1992; Wood et al., 1994 for details). The pressure on local 612 Richardson et al. authorities to rezone large parts of the Cape Peninsula for urban development will undoubtedly increase markedly over the next few decades. These developments may place increasing pressure on authorities to review the current regulations that preclude development on publicly-owned land and within the boundaries of the Cape Peninsula Protected Natural Environment (CPPNE: see Cowling et al., 1996; van Wilgen, 1996). There are, as yet, no informal settlements proclaimed within the CPPNE, and the most recent structure plans for the region affirm the status of the CPPNE, but this could change. (2) The control of invasive alien plants is extremely expensive, and a large part of the funds previously allocated for this purpose (averaging around 17% of the total budget for nature conservation in the Western Cape in recent years) is likely to be diverted to issues more closely associated with the reconstruction and development of a post-apartheid South Africa. The negative effect of reduced funding for mechanical control may be reduced to some extent by the increasing efficiency of biological control measures (as existing agents become more widely established and new agents are released) and by increasing utilization of the alien plants (e.g. co-ordinated harvesting of alien Acacia spp. for firewood: Azorin. 1994). We considered three scenarios for urbanization. and four for alien plant invasions that take account of these factors (Table 2). Results VEGETATION TYPES. SPECIAL TAXA PLANT SPECIES DIVERSITY AND THE OCCURRENCE OF Three of the 15 recognized vegetation types (sandplain proteoid fynbos. mesic oligotrophic fynbos and mesic mesotrophic fynbos) originally covered almost 60% of the Peninsula, with another three types (dune asteraceous fynbos. wet restioid fynbos and wet mesotrophic proteoid fynbos) contributing another 24% (Fig. 1; Table 3). Table 3 shows salient elements of plant biodiversity of each vegetation type (see also Simmons and Cowling, 1996; Trinder-Smith et al.. 1996a for further discussion). THE CURRENT EXTENT OF URBANIZATION AND AGRICULTURE Urbanization and agriculture have transformed 18172 ha (37%) of the original area of natural vegetation of the Cape Peninsula (Fig. 2; Table 4). Almost half of the urbanization has occurred in one vegetation type (sandplain proteoid fynbos) and almost all the rest in another five types that occur mainly on level areas at low altitudes (Fig. 1: Table 4). Similarly. 90% of agricultural transformation has occurred in three lowland vegetation types (types SND, MMP and WMP in Table 4). These two categories of land transformation have together destroyed 48% of dune asteraceous fynbos. 77% 01 sandplain proteoid fynbos, 75% of wetlands, 70% of wet mesotrophic proteoid fynbos. 60% of renosterveld and grassland, and 32% of the area of vleis (Fig. 1; Table 4). On the other hand, vegetation types that occur predominantly at high altitudes (types WRF, ERI, MOP, CLF, WOP and URF in Table 4) have been little affected by agriculture and urbanization, and more than 90% of their original area remains (for types ERI, CLF, WOP and URF, most of the remaining area is lightly invaded; Table 5). 613 Threats to biodiversity on the Cape Peninsula Table 2. Seven scenarios of possible changes in the extent of urbanization and invasion by alien trees and shrubs on the Cape Peninsula. The CPPNE is the Cape Peninsula Protected Natural Environment (see Cowling el al., 1996) Assumptions Scenario Urbanization Ul No further urbanization within the boundaries of the CPPNE, but all remaining areas suitable for urbanization are developed CPPNE legislation maintained in the face of increasing demand for land; large-scale development elsewhere u2 All areas suitable for urbanization outside public land are developed Relaxation of regulations restricting development in the CPPNE; only public land remains for conservation u3 Development of all suitable irrespective of land ownership areas, Total break-down of legislation governing development on protected sites, or the modification of legislation to permit development over a larger area Al All dense stands of alien plants are cleared Major investment of funds towards integrated control; effective liaison landowners, between conservation authorities and volunteer groups to compile and implement effective strategies; biological control is effective and prevents re-establishment of dense stands after mechanical control A2 All dense alien stands within the CPPNE are cleared, but all other potential sites become covered with dense stands Substantial investment of funds, but efforts (see Al) are confined to the CPPNE; control efforts outside CPPNE poorly coordinated and ineffective; biological control moderately effective, but little effect on dense stands A3 All dense alien stands on public land are cleared, but all other potential sites become covered with dense stands Available funds restrict co-ordinated integrated control to public land; biological control moderately effective, but little effect on dense stands A4 Alien plants spread to form dense stands in all potentially invadable areas Reduction, in real terms, of funding available for control; existing dense stands persist and become even denser after each fire; dense stands serve as foci for further spread; stand density increases in lightly invaded areas; efforts by volunteer groups are ineffective: net effect of biological control and harvesting insufficient to contribute to overall control Alien plants Table 3. Salient features of plant biodiversity in 15 vegetation types on the Cape Peninsula. Numbers in brackets in column 2 are the areas of each vegetation type expressed as percentages of the total area. In column 3. numbers in brackets are the numbers of plant species per ha (original area) for each vegetation type. Asterisks in columns 4 and 5 indicate vegetation types with higher than average numbers of endemics (mean = 23.7) or threatened plant taxa (mean = 32.5) Vegetation 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. types Forest and thicket (FOR) Dune asteraceous fynbos (DUN) Coastal scree asteraceous fynbos (CSA) Wet restioid fynbos (WRF) Ericaceous fynbos (ERI) Sandplain proteoid fynbos (SND) Mesic oligotrophic proteoid fynbos (MOP) Mesic mesotrophic proteoid fynbos (MMP) Undifferentiated cliff communities (CLF) Wetlands (WET) Wet oligotrophic proteoid fynbos (WOP) Wet mesotrophic proteoid fynbos (WMP) Renosterveld and grassland (REN) Upland restioid fynbos (URF) Vleis (VLE) TOTAL Original (ha) area Number of plant species Number endemic 1315 (2.7) 4 331(8.8) 256 (0.5) 3 244 (6.6) 1342 (2.7) 10576 (21.5) 8830(18.0) 9 161(18.6) 722(1.5) 1434 (2.9) 1054 (2.1) 4 081(8.3) 2 419 (4.9) 149 (0.3) 213 (0.4) 924 (0.70) 873 (0.20) 170 (0.66) 333 (0.10) 764 (0.57) 1133(0.11) 1 122 (0.13) 1589 (0.17) 524 (0.73) 965 (0.67) 396 (0.38) 1 139 (0.28) 974 (0.40) 153 (1.03) 86 (0.40) 11 29’ 4 32’ 29’ 40* 59’ 49’ 17 20 23 24* 8 9 2 49 127 2285 90 of plant taxa Number of threatened plant taxa 17 44: 5 40’ 34’ 55’ 87’ 79* 21 29 20 23 18 12 4 141 z 2 Threats to biodiversity on the Cape Peninsula 615 VEGETATION TYPE Figure 1. The original extent and status (in 1994) of 15 vegetation types on the Cape Peninsula (total area = 49 127 ha). Categories are: URBAN, AGRIC (land transformed by urbanization and agriculture), ALIEN-D, ALIEN-L [areas under dense (>25% canopy cover) and light (~25% canopy cover) stands of alien trees and shrubs], and PRISTINE (areas not affected by agriculture, urbanization or alien plants). Codes for vegetation types refer to those in Table 3. THE CURRENT EXTENT OF INVASIVE ALIEN PLANTS Of the 30955 ha of natural vegetation remaining on the Cape Peninsula (i.e. that not affected by agriculture or urbanization), 3313 ha (10.7%) are covered in dense stands (~25% canopy cover) of invasive alien trees and shrubs, and another 10 184 ha (32.9%) is lightly invaded (~25% canopy cover; Fig. 3; Table 5). Vegetation types with the largest parts of their remaining area under dense stands of aliens are coastal scree asteraceous fynbos (46%) and dune asteraceous fynbos (32.8%), although the most extensive stands of dense aliens (1013 ha; 30.6% of the total) occur in mesic mesotrophic fynbos (Fig. 1; Table 5). The large dense stands in this vegetation type, comprising mainly Acacia cyclops and Eucalyptus spp., are affecting 23 (14.3%) of the special plant taxa on the Peninsula. Acacia cyclops is the most important invader in seven vegetation types (Table 5); dense stands of this species cover 2510 ha, 76% of the total area of dense alien stands. Of the 10 184 ha of lightly invaded areas, the largest area occurs in mesic mesotrophic proteoid fynbos (43.6% of the remaining area of that type). Vegetation types with more than half of their untransformed area under light infestations of alien trees and shrubs are forest and thicket, ericaceous fynbos, undifferentiated cliff communities, renosterveld and grassland, and upland restioid fynbos (Fig. 1; Table 5). The altitude ranges and preferred vegetation types of the ten most widespread alien species are given in Table 6. All species occur over a wide range of altitudes and invade several vegetation types. Dense stands of alien plants are affecting 23 endemic, rare and Richardson et al. Figure 2. The current extent of urbanization 4 for details). and agriculture on the Cape Peninsula (see Tables 1 and Table 4. The extent of urbanization and agriculture in 15 vegetation types on the Cape Peninsula in 1992 and the impact of these transformations on endemic, rare and threatened plant taxa (a taxon is deemed to be affected if urbanization or agriculture encroaches into the 1 km2 square in which it occurs) Vegetation type 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. Forest and thicket (FOR) Dune asteraceous fynbos (DUN) Coastal scree asteraceous fynbos (CSA) Wet restioid fynbos (WRF) Ericaceous fynbos (ERI) Sandplain proteoid fynbos (SND) Mesic oligotrophic proteoid fynbos (MOP) Mesic mesotrophic proteoid fynbos (MMP) Undifferentiated cliff communities (CLF) Wetlands (WET) Wet oligotrophic proteoid fynbos (WOP) Wet mesotrophic proteoid fynbos (WMP) Renosterveld and grassland (REN) Upland restioid fynbos (URF) Vleis (VLE) TOTAL Original area (W Urbanization ---------------Area Number l~urnoer of or endemic. enaemic. rare and threatened (ha) taxa affected 1315 4331 256 3244 1342 10 576 8 830 9161 722 1434 1054 4081 2419 149 213 75 2 096 19 0 0 7 277 2 1561 0 1072 0 1741 1428 0 69 49 127 15 340 0 26 0 0 0 57 0 16 0 33 0 10 15 0 3 Agriculture --------------Area Number l\urnr of endemic, rare aand threatened 0-d taxa iaffected 133 0 0 93 0 866 15 582 0 11 24 1106 2 0 0 2 832 0 0 0 3 0 2 0 11 0 0 0 2 0 0 0 Extent of natural vegetation remaining (ha) (% of original) 1107 (84.2) 2 235 (51.6) 237 (92.6) 3 151(97.1) 1342 (100.0) 2433 (23.0) 8 813 (99.8) 7018(76.6) 722 (100.0) 351(24.5) 1030 (97.7) 1234 (30.2) 989 (40.9) 149 (100.0) 144 (67.6) 30955 (63.0) q-’ 7 9. Q 3 w 0 5 Table 5. The extent of dense (>25% canopy cover) and light stands (c2.5 % canopy cover) of alien trees and shrubs (including pine plantations) in 15 vegetation types on the Cape Peninsula in 1994, and the number of endemic, rare and threatened plant taxa affected by such stands. Numbers in brackets are areas invaded expressed as percentages of the area remaining (i.e. not affected by urbanization and agriculture) for each vegetation type Veeetation Y tvm 11 remaining (ha) 1. Forest 2. Dune and thicket (FOR) asteraceous fynbos (DUN) 3. Coastal scree asteraceous fynbos 4. Wet restioid fynbos (WRF) 5. Ericaceous fynbos 6. Sandplain proteoid (CSA) fynbos (SND) invaded Dense (%) (ha1 Endemic Light (% ) Dense and threatened Light taxa Uninvaded 1 107 lgl(l6.4) 720 (65.0) 1 20 ‘4 2 23s 733 (32.8) 3X(16.0) s 9 21 237 3 151 109 (46.0) 16 (0.5) 57 (24.1) 445(14.1) 2 2 5 14 36 X14(60.7) 0 34 17 I 342 (ERI) Area 0.2 (0.0) 2 433 464flY.l) X75 (36.0) 4 9 IX 7. Mesic oligotrophic proteoid fynbos (MOP) X813 46X (5.3) I601 (18.2) 19 31 99 X. Mesic proteoid fynbos (MMP) 701x I013 (14.4) 3 062 (43.6) 23 s4 4s 35 (4.X) 447 (62.0) 2 1Y 10 0 14 21 mesotrophic 9. IJndifferentiated cliff commumties (CLF) 722 IO. Wetlands (WET’) 11. Wet oligotrophic proteoid fynbos (WOP) 351 I 030 33 (9.4) 0.4 (0.0) 43 (12.3) 408 (39.6) 0 0 12. Wet mesotrophrc fynbos (WMP) I 234 lSJ( 12.5) 56X (46.(J) 4 ‘)x9 I07 (10.X) 637 (64.4) I 149 144 0 (0) 0 (0) 149 (loo) O(O) I) 0 13. Renosterveld 14. Upland rest&id 15. Vleis (VLE) I-OTAL proteoid and grassland fynbos ( lJRF (REN ) ) 10 955 3313.6 10 1x4 13 0 2 Major alien species (in order of importance) Acacia cyclops, Pinus radiata. Eucalyptus spp.. P. pinaster. E. lehmannii Acacia cyclops, A. salignu. Eucalyptus spp., E. lehmannir. Pinus radio&z Acacia cyclops Eucalyptus spp.. E. lehmannii, Acacia longifolia, Pinus pinaster, P. pinea Pinus mdiata, P. pinaster. Eucalyptur spp. Acacia cyclops, Eucalyptus spp.. Leptospermum laevigatum, Popultu spp.. A. soligna Pinus pinaster, Acacia cyclops. A. longifolia. Eucalyptus spp.. P. pinea Acacia cyciops, Eucal.vptus spp.. A. saligna, Pinus radiata, P. pinaster Acacia cyclops, Pinus pinaster. Eucalyptus spp. Acacia cyclops, Eucalyptus spp. Acacia saligna, Pinus mdiata, Eucalyptus spp..A. cvclops. P. pinaster Pinus radiata, Eucalyptus spp.. Acacia saligna, Pinus pinaster. A. cyclops. Paruverianthes lophantha Eucalyptus spp., rlaK1u 1.yclop., Pinus pinaster. P pinra 619 Threats to biodiversity on the Cape Peninsula threatened taxa in mesic mesotrophic proteoid fynbos (Table 5). proteoid THE COMBINED EFFECT OF URBANIZATION, AND SHRUBS fynbos, and 19 in mesic oligotrophic AGRICULTURE AND ALIEN TREES The area currently not affected by agriculture, urbanization or dense stands of alien plants (Fig. 4) amounts to 27 642 ha, or 56.3% of the original extent of natural vegetation. The largest areas of pristine vegetation (i.e. that unaffected by alien trees and shrubs, agriculture and urbanization) occur in mesic oligotrophic proteoid fynbos, wet restioid fynbos, mesic mesotrophic fynbos and dune asteraceous fynbos (Fig. l), all types with higher than average numbers of endemic and threatened plant taxa (Table 3). PREDICTED IMPACT OF URBANIZATION BIODIVERSITY AND AGRICULTURE ON PLANT Increased levels of urbanization result in a steady (more-or-less linear) loss of biodiversity. In 1992, all records for 6.6% of the special taxa occurred in 1 km* squares that are already affected by urbanization (Fig. 5A; Appendix l), and 5.3% of Proteaceae taxa were similarly affected (Fig. 5E); these taxa are seriously threatened. For 42.5% of special taxa and 34.2% of Proteaceae, no mapped localities are currently affected by urbanization. For 86% of the special taxa more than half of the localities are in l-km* squares that are not currently affected by urbanization. All but two of the Proteaceae taxa also have half or more of their range unaffected by urbanization. A scenario of full urbanization outside the CPPNE (Ul) results in an 11.4% reduction in the extent of natural vegetation, with sandplain proteoid fynbos (21.5%) and wetlands (36.5%) being worst affected (Fig. 6A; Table 7). Some 26.9% of localities of special taxa (2.9% for Proteaceae) are affected; for 7.8% of special taxa and 5.3% of Proteaceae all known localities are urbanized (Fig. 5, B and F). The percentage of special taxa with more than half of their known localities affected increases from 13.8% to 17.4%; for the Proteaceae the number of taxa thus affected remains unchanged. Scenario U2 (complete urbanization on suitable areas outside public land) leads to further deterioration, reducing the extent of natural vegetation to 24681, or 79.7% of the area remaining in 1994. Under this scenario, sandplain proteoid fynbos occupies only 842 ha (8% of its extent before human settlement)(Fig. 6B). Just less than half of the special taxa lose 50% or more of their known localities to urbanization, with 8.4% of them now occurring only in squares affected by urbanization. The additional habitat loss brought about by scenario U2 (most of it involving loss of vegetation types DUN, SND, MOP and MMP; Fig. 6A) affects 78 Proteaceae localities, but still only 2 taxa (Diastella divaricata divaricata and Leucadendron levisanus) have 100% of their range affected (Appendix 2). 57.4% of known localities of the 161 special taxa, and 40.1% of Proteaceae localities, are affected by urbanization under scenario U3 which involves development of all suitable areas, irrespective of land ownership (Fig. 5, D and H); this scenario sees the natural vegetation reduced to only 39.3% of its extent in 1994, with dune asteraceous fynbos, wet restioid fynbos, sandplain proteoid fynbos (vegetation types with many endemic and threatened taxa; Table 3) and wetlands being almost totally transformed (Fig. 6, A and B). Under this scenario almost a quarter of special taxa are confined totally to urban areas or areas within less than 1 km of such developments - 24 more taxa than under scenario U2. All mapped Richardson et al. 620 [• Light Infestation Dense Infestation Figure 3. The distribution of alien woody plants on the Cape Peninsula in 1994. (Black = dense stands; >25% canopy cover; grey = lightly invaded areas; <25% canopy cover.) See Table 5 for details on areas of each vegetation type invaded, the most important invaders in each vegetation type, and the number of special taxa threatened by aliens in each vegetation type. Profiles for the ten most widespread aliens are given in Table 6. Threats to biodiversity on the Cape Peninsula 621 Table 6. Profiles for the ten most widespread alien woody speciesin terms of altitude and vegetation type (see text) Species Acacia cyclops Eucalyptus spp. (excludingE. lehmannii) Pinus radiata Pinus pinaster Acacia saligna Pinus pinea Acacia longifolia Leptospermum laevigatum Eucalyptus lehmannii Hakea gibbosa Area of dense stands(ha) 2510 Altitude range (m above sealevel) l-573 Vegetation types (numbersrefer to typesin Table 3) 1121 908 568 507 240 236 201 201 131 14-588 52-614 18-955 20-427 40-319 32-588 40-300 l-329 110-414 1,4,5,6,7,8,9, 10, 11,12,13 1,2,5.6,7,8,11, 12,13 1,4,5,6,7,8,9,11, 12, 13 1,2,6,7,8, 11, 12,13 1,4,6,7,8, 12, 13 1,4,6,7, 8,12 6, 7, 8, 13 1,2,4,7,8 1, 2, 3,6,7,8,9, 10, 11, 12, 13 ‘5,738 localities for four Proteaceae taxa (Diastefla divaricata divaricata, Leucadendronfloridum, L. levisanus and L. macowanii) are urbanized. All but four of the 15 vegetation types (ERI, CLF, WOP and URF) will lose a large part of their area under the three urbanization scenarios described here (Fig. 6A; Table 7). Another four types (DUN, WRF, MOP and MMP) lose major parts of their area only under the worst-case scenario (U3). PREDICTED IMPACT OF INVASIVE ALIEN PLANTS ON PLANT BIODIVERSITY The 3313 ha of dense alien stands in 1994 affect 349 (29.8%) of the 1170 localities of special taxa known from herbarium records, and 8.4% of these taxa currently occur only in areas already affected by aliens. Dense alien stands affect 30 of the 38 Proteaceae taxa in part of their range, and the entire range (as shown from our records) for two species (Diastella proteoides and Leucadendron levisanus) are already affected (Appendix 2). However, more than half of the (recent) records for 35 of the 38 Proteaceae taxa are in areas that are not currently affected by dense alien stands. Clearing of all dense alien stands (with concomitant invasion of all other potential sites; scenario Al) would result in 62.9% of special taxa having less than half of their known localities affected by dense stands (49.1% at present). Under this scenario, 92% of Proteaceae taxa have more than 75% of their localities unaffected by aliens. The vegetation types that would benefit most from this scenario are coastal scree asteraceous fynbos and dune asteraceous fynbos; realization of this scenario would result in 96% and 49% increases in the extent of uninvaded areas of these types, and a 12% increase in the total extent of natural vegetation not under dense stands of aliens (Table 7). If funds allow alien control only within the CPPNE (but invasion continues outside this area; scenario A2), the total area of vegetation not under dense stands would remain virtually the same as it is at present, with the area under uninvaded vegetation increasingfor some types (notably CSA and FOR) and shrinking for others (notably SND and WET; Table 7). Scenario A3, whereby control efforts are confined to publicly-owned land, sees the shrinkage of the total area under uninvaded vegetation to 82.4% of its current extent, with marked reductions in the extent of most vegetation types. Only types CSE and CLF would benefit under this scenario. Scenario A4 which sees the collapse of control programmes and the rampant spread of the aliens to all potential sites 622 Richardson et al. Figure 4. The extent of natural vegetation on the Cape Peninsula in 1994 (land unaffected by urbanization, agriculture and dense stands of aliens). This area includes lightly invaded areas. Threats to biodiversity on the Cape Peninsula 623 results in the annihilation of the vegetation, with only 407 ha (1.5% of the current area) remaining. The impacts on special taxa and the Proteaceae under scenarios A2, A3 and A4 are summarized in Fig. 7, and details for each taxon are given in Appendices 2 and 3. The worst-case scenario (A4) results in about a quarter of special taxa and more than 15% of Proteaceae species being confined entirely to densely invaded sites, with most other taxa having large parts of their ranges affected. Species that are currently common and widespread will lose large parts of their range. Discussion The Cape Peninsula has already lost a considerable part of the natural vegetation (and therefore biodiversity) that existed in the area at the time of European settlement. Large areas of lowland vegetation have, as in other parts of the Cape Metropolitan Area (Wood et al., 1994), been transformed. Lowland vegetation types, including renosterveld, dune fynbos and sandplain proteoid fynbos, have also been severely impacted in other parts of the Western Cape (Moll and Bossi, 1984; Rebelo, 1992). The rugged topography of the Peninsula has limited the extent of urbanization and agriculture, and the bulk of the remaining vegetation occurs in the mountains, although much of this is threatened by alien trees and shrubs. In this respect, the situation on the Peninsula reflects that of the entire fynbos biome, where most remaining natural vegetation is in the mountains (see Rebelo, 1992 for details). It is extraordinary, given the extent of transformation of natural vegetation and the fact that many fynbos plant species have small population sizes that are restricted to small areas, that only 39 plant taxa are known to have become extinct on the Peninsula during the 20th century. The extent of recent (post-1900) plant extinctions on the Peninsula (1.7% of the flora) is, however, higher than that for the entire fynbos biome (26 species out of 7300 = 0.36%; Hall and Veldhuis, 1985). Although only 39 taxa have become extinct on the Peninsula, many others now occur over much smaller areas, and have therefore lost much of their genetic diversity. Many taxa now occur in small scattered populations which are separated by tracts of transformed land and are subjected to levels of disturbance to which they are not pre-adapted (e.g. fires at short intervals). The nature and magnitude of the disruptions of essential processes caused by fragmentation have not been studied in any detail. Different taxa respond differently to fragmentation and the other consequences of the threats described in this paper. We therefore do not know exactly how serious (for its continued existence) it will be for a given taxon to lose, for example, 50,75, or 99% of its current range. It is clear, however, that the likelihood of a taxon becoming extinct increases as populations become smaller and more isolated. Many plant taxa on the Cape Peninsula are critically threatened (see Trinder-Smith et al., 1996a). It follows that major losses in biodiversity will occur on the Cape Peninsula (and throughout the fynbos biome) if urbanization and the area under alien plants are allowed to increase. The scenarios of changing threats to biodiversity discussed in this paper are a small subset of the possible consequences of changes in the socio-political events that control patterns of urbanization and of the economic and ecological factors that influence the extent of alien plant invasions. We modelled the impacts of changes in urbanization and alien plant invasions separately to keep the patterns interpretable, but these two factors will change together. Nevertheless, the scenarios are useful for assessing the magnitude of A: ENDEMIC, RARE 6 THREATENEO TAXA -1992 8w 3 z40 8 2 20 0 a l-25 51-75 26-50 PERCENTAQE RANGE 76-99 loo 0 I-t3.S 26-50 PERCENTAGE AFFECTED 51-75 RANQE 76-99 AFFECTED 100 8: ENDEMIC, RARE 6 THREATENED TAXA -SCENARIO F: PROTEACEAE-SCENARIO VI Ul 20 0 0 l-25 PERCENTAGE 2@8-50 51-75 RANQE 76-99 AFFECTED loo PERCENTAGE RANQE AFFECTED loo loo, 100 C: ENDEMIC, RARE L THREATENEO TAXA .BCENARIO U2 Q: PROTEACEAE-SCENARIO U2 Y iTIm P 20 0 0 1-25 25-50 PERCENTAGE 51-75 RANGE 75-9s loo 0 l-25 51-75 26-50 PERCENTAQE AFFECTED RANQE 75-9s 100 AFFECTED 100 D: ENDEMIC. 0 RARE & THREATENEO l-25 PERCENTAQE 25-50 TAXA -SCENARIO 51-75 RANQE 75-m AFFECTED H: PROTEACEAE-BCENAWO US loo 0 l-25 PERCENTAGE 25-50 US 51-75 RANQE 75-99 loo AFFECTED Figure 5. The current impact of urbanization on endemic, rare and threatened taxa (A) and Proteaceae taxa (E), and predicted impacts under three scenarios of urban spread (B-D and F-H) (see Table 2 for descriptions of scenarios). Richardson et al 626 A 12 SCENARIO VEGETATION TYPE SCENARIO 0 LEFT RIU3 80 p a 2* RlJ2 uau1 D PRESENT E VEGETATION TYPE Figure 6. The original extent of 15 vegetation types on the Cape Peninsula and areas currently affected by urbanization (PRESENT) and the predicted extent of urbanization in each under three scenarios (see Table 2). (A) areas (ha). (B) Proportions of total areas affected. Codes for vegetation types refer to those in Table 3. changes that are likely if certain policy decisions are taken, or if the other eventualities detailed in Table 2 materialize. Increasing urbanization has a steady effect on biodiversity (the linear increase in impacts being the result of limits sets by environmental features and planning) whereas the spread of alien plants is exponential (since the major invaders can colonize almost all habitats and there is virtually no control on population growth). 2 ;E: 3 3 B 8 Table 7. The area of each of 15 vegetation types remaining unaltered under seven scenarios relating to the spread of urbanization and the various control/spread possibilities for invasive alien trees and shrubs on the Cape Peninsula (see Table 2 for details of the scenarios). Note that the areas S’ m remaining given for the urbanization scenarios exclude areas under dense alien stands, since these areas are available for urbanization. Numbers in 22 k brackets under column totals are the total areas expressed as a percentage of the area remaining in 1994 g Vegetation type Forest and thicket (FOR) Dune asteraceous fynbos (DUN) Coastal wee asteraceous fynbos (CSA) Wet restioid fynbos (WRF) Ericaceous fynbos (ERI) Sandplain proteoid fynbos (SND) Mesic oligotrophic proteoid fynbos (MOP) Mesic mesotrophic proteoid fynbos (MMP) Undifferentiated cliff communities (CLF) Wetlands (WET) Wet oligotrophic proteoid fynbos (WOP) Wet mesotrophic proteoid fynbos (WMP) Renosterveld and grassland @EN) Upland restioid tjmbos (URF) Vleis (VLE) TOTAL Area of each vegetation type remaining under three scenarios relating to urbanization (see table 2) Area of each vegetation type remaining under four scenarios relating to the spread----------------------of invasive alien plants (see Table 2) Area remaining SC. Ul SC. u2 SC. u3 Area 1107 2 235 237 3 151 1342 2433 8813 7018 722 351 1030 1234 989 149 144 1034 1733 186 3 151 1342 1272 8581 6107 722 223 1029 975 787 149 128 961 1295 185 3 151 1342 842 7899 5260 720 189 1019 825 742 149 101 548 108 93 42 1342 124 3681 3286 709 41 1019 554 372 149 95 30 955 27419 (88.6%) 24 680 (79.7%) 12 163 (39.3%) remaining SC. Al SC. A2 SC. A3 SC. A4 926 1502 128 3 135 1342 1%9 8345 6005 687 318 1030 1080 882 149 144 1106 2235 237 3 151 1342 2 434 8813 7019 722 351 1029 1234 989 149 144 1031 1733 178 3 151 1342 1270 8511 6065 722 223 1029 975 786 149 128 900 1273 176 3 149 1342 816 7000 4554 706 189 924 775 730 149 101 1 82 2 0 33 4 0 4 17 18 1 11 1 138 95 27 642 30 955 (112.0%) 27 293 (98.7%) 22784 (82.4%) 407 (1.5%) B 0 5 “tr 2. 2 E: F loo A: ENDEMIC, RARE L THREATENED F: PROTEACEAE TAXA -1094 -1004 80 P 0 Y ea g4a 8 20 0 .-I 1 1 PERCENTAOE RANQE PtERCENTAGE AFFECTED RANGE AFFECTED 100 B: ENDEMIC, RARE L THREATENED TAXA -SCENARIO Al Q: PRDTEACEAE -SCENARIO Al I 40 20 0 PERCENTAQE 7 RANQE PhRCENTAGE AFFECTED RANGE 100 C: ENDEMIC. RARE 6 THREATENED TAXA -SCENARIO H: PROTEACEAE A2 I -SCENARIO A2 AFFECTED kh 0 1 l-25 PERCENTAQE 2550 51-75 RANaE 75-99 alLI_; loo 0 AFFECTED 100 25-50 51-75 RANGE 75--99 100 AFFECTED 100 D: ENDEMIC, RARE A THREATENED TAXA -SCENARIO AS PERCENTAaE RANOE I: PROTEACEAE -SCENARIO AFFECTED PERCENTAQE 100 AS RAN=E AFFECTED 1oc E: ENDEMIC, P 1-25 PERCENTAaE RARE A THREATENED TAXA -SCENARIO A4 J: PROTEACEAE -SCENARIO A4 I 50 50 I SC IL 40 E 20 Pa 2c 0 PERCENTAGE RANQE AFFECTED 2650 l-25 PERCENTAGE Figure 7. The current impact of dense stands of invasive alien plants on endemic, Proteaceae taxa (E), and predicted impacts under four scenarios of control/spread scenarios). 51-75 RANGE 75-22 loo AFFECTED rare and threatened taxa (A) and (see Table 2 for descriptions of 630 Richardson et al. Invasive alien plants almost certainly pose the greatest threat to biodiversity, since new structure plans entrench the status of the CPPNE and this should prevent the encroachment of urbanization into the area (although this could change). At present. 10 184 ha (36.9%) of remaining vegetation (that not affected by urbanization, agriculture or dense alien stands) is lightly invaded. Research in other parts of the fynbos biome has shown that lightly invaded areas, and even areas totally free of aliens, can become densely invaded over two or three fire cycles (Richardson and Brown, 1986). The lightly invaded vegetation, with its many endemic, rare and threatened taxa (Table 5) is, therefore, by no means safe from the influence of invasive alien plants. It is much easier and cheaper to clear aliens before stands become dense, and control programmes should give priority to clearing these areas and keeping them free of aliens. The information gathered for this study can be used to establish priorities for controlling dense stands using objective criteria related to the various indices of biodiversity. For example, we can rank densely invaded areas according to their impact on a particular vegetation type, a particular species, or on any of a number of indices of the overall biodiversity. But there are many unknowns. For example, we have assumed that the pressure on biodiversity is annulled if dense alien stands are cleared. In other parts of the fynbos biome clearance of dense stands of alien trees and shrubs using mechanical felling and burning (which is usually the only practical option) has caused further damage, for example by changing the physical structure of the soil and eliminating those resprouting species that usually persist under dense stands (Richardson and van Wiigen, 1986; Breytenbach, 1989). Research is currently underway to assess the biodiversity under dense stands of different ages and in cleared areas, and to determine ways of clearing dense stands of aliens with the least possible damage to the remaining biodiversity (P.M. Holmes, pers. comm.). The clearing of alien plants is an urgent priority for the Cape Peninsula. A major injection of funds is required to support an integrated programme of alien plant control. This study has emphasized the importance of considering the impact of the various threats on widespread species, and not just the ‘special’ taxa. Many plant taxa on the Peninsula (Simmons and Cowling, 1996) and elsewhere in the fynbos biome (Hall and Veldhuis, 1985) are fairly widespread overall, but occur as small scattered populations which are often associated with rare or otherwise peculiar habitats (Cowling and Holmes. 1992). If transformation destroys special habitats, then local (and total, for ‘beta rares’ Sense Cody, 1986) extinction is inevitable. More research is required on all aspects of rarity in the Peninsula flora (see also Simmons and Cowling, 1996). Changes to the fire regime also pose an important threat to the Peninsula’s biodiversity since fynbos ecosystems are fire-prone and fire-dependent (van Wilgen etal., 1990). Before human settlement of the area, the fire regime would probably have comprised fires of moderate intensity at intervals of between 6 and 40 years, usually in summer or early autumn, but with occasional fires in other seasons (van Wilgen. 1987). A number of factors have altered this regime, including fragmentation of the vegetation, the introduction of fire protection policies and artificial sources of ignition, and changes in fuel loads brought about by invasive alien trees and shrubs. There are no data for constructing a meaningful picture of the current or historic fire regimes on the Peninsula. Fire records are only kept for the Table Mountain, Silvermine and Cape of Good Hope Nature Reserves, and these have only been kept for the past 15 or 20 years. An analysis of the situation on Table Mountain (Richardson et al., 1994) showed that the vegetation was largely mature (57% had a post-fire age of greater than 20 years). Threats to biodiversity on the Cape Peninsula 631 Almost all recorded fires took place in January, and only 5% of the area burnt between May and October. The age at which vegetation burned could not be accurately determined, as the dates of previous fires were unknown for many sites. Changes to the fire regime on the Peninsula may threaten biodiversity in several ways: increases or decreases in fire frequency, or changes in fire behaviour and intensity brought about by the invasion by alien trees and shrubs. In the first instance, short fire intervals may eliminate species that are killed by fire and rely on seed to reproduce. On the other hand, long intervals between fires eliminate species with short lifespans that rely on fire to trigger seed release and germination (van Wilgen et al., 1992). There is no evidence that any such cases have occurred on the Peninsula to date. Although fire protection and fragmentation of the landscape could have resulted in decreases in fire frequency, increases in the human population and development may have counteracted this by providing additional sources of ignition. Public resistance to an orderly implementation of a programme of prescribed burning may also represent a significant threat; at present very few prescribed bums are conducted on the Peninsula. Mechanical clearing in conjunction with prescribed burning is the only practical way to clear dense stands of most of the major aliens on the Peninsula (Richardson et al., 1996). The failure, due to public pressure, to maintain a systematic programme of prescribed burning means that alien control efforts are wasted, since every wildfire burns through untreated alien stands, resulting in further proliferation and spread. Another fire-related threat to biodiversity is caused by the increases in fuel loads brought about by alien plants. In some areas, these increased fuel loads have been shown to result in substantial increases in fire intensity, inducing water repellant layers in the soil and increasing runoff (Scott and van Wyk, 1990). This phenomenon has been held responsible for increases in erosion following fires on Table Mountain, for example (Scott et al., 1991). van Wilgen et al. (1992) discussed the possible impacts of global climate change on elements of fynbos biodiversity under various scenarios. They suggest that the impacts will be greatest on the lowlands, where seed-regenerating shrubs are likely to be most severely threatened. Conclusions The Cape Peninsula has already lost a large part of its biodiversity. Without intervention and careful planning the situation will deteriorate rapidly. This study has shown the need to stabilize and defend the boundary of the Cape Peninsula Protected Natural Environment (CPPNE). No urbanization should be permitted within its boundaries and a major injection of funds is required to support an integrated programme of alien plant control. The 10 l&4 ha of lightly invaded vegetation should be tackled before the 3313 ha of densely invaded vegetation (because less dense stands are easier and cheaper to control, and control at this stage removes the aliens before the major damage is caused). Table 5 provides an objective basis for allocating priority for such control measures. Contingency measures need to be implemented to improve the status of seriously threatened taxa, habitats and vegetation types. Acknowledgements For assistance with data collection, collation and analysis we thank Blair Ludbrook, Greg Forsyth, Clare Jones and Rene Robyntjies. The bulk of data collection, collation and 632 Richardson et al. analysis on GIS was funded by the CSIR’s Division of Forest Science and Technology. The Institute for Plant Conservation also contributed funds for mapping of alien plants and for GIS analysis. We thank the Cape Town City Council (James Jackelman) for providing data on alien plant distribution for some areas under their control. Nick Cole and Tony Rebel0 kindly supplied digital data on the distribution of Proteaceae from the on-going Protea Atlas Project. RMC acknowledges the financial support of the Pew Charitable Trusts. We thank Richard Hobbs and Timm Hoffman for their perceptive comments on the manuscript. References Azorin, E.J. (1994) The utilization of invasive alien acaciasas part of an integrated management plan for the conservation of fynbos in the southern Cape Peninsula. Unpublished report. Institute for Plant Conservation, University of Cape Town. Breytenbach, G.J. (1989) Alien control: can we afford to slash and burn hakea in fynbos ecosystems’? S. Afr. For. J. 151,6-16. Bridgman, D.H.M., Palmer, I. and Thomas, W.H. (1992) South Africa’s Leading Edge? A Guide to the Western Cape economy. Cape Town: WESGRO. Cody, M.L. (1986) Diversity, rarity, and conservation in mediterranean-climate regions. In Conservation Biology: the Science of Scarcity and Diversity (M.E. SoulC. ed.) pp. 122-52. Sunderland, MA: Sinauer. Cowling, R.M. and Holmes, P.M. (1992) Flora and vegetation. In The Ecology of Fynbos: Nutrients, Fire and Diversity (R.M. Cowling, ed.) pp. 23-61. Cape Town: Oxford University Press. Cowling, R.M., Macdonald, I.A.W. and Simmons, M.T. (1996) The Cape Peninsula, South Africa: physiographical, biological and historical background to an extraordinary hotspot of biodiversity. Biodiv. Conserv. 5, 527-50. Di Castri, F. (1994) Politics and environment in mediterranean-type climate regions. Noticiero de Biologia 2, 16. Hall, A.V. (1987) Threatened plants in the fynbos and karoo biomes, South Africa. Biol. Conserv. 40, 29-52. Hall, A.V. and Ashton, E.R. (1983) Threatened plants of the Cape Peninsula. University of Cape Town: Threatened plants Research Group. Hall, A.V. and Veldhuis, H.A. (1985) South African Red Data Book: Plants - Fynbos and Karoo Biomes. S. Afr. Nat. Sci. Prog. Rep. 117, l-160. Hobbs, R.J., Richardson, D.M. and Davis, G.W (1995) Mediterranean-type ecosystems: Opportunities and constraints for studying the function of biodiversity. In Mediterranean-type Ecosystems: the Function of Biodiversity (G.W. Davis and D.M. Richardson, eds) pp. 1-42. Ecological Studies 109. Berlin: Springer-Verlag. Le Maitre, D.C. and Versfeld, D.B. (1994) Field Manual for Mapping Populations of Invasive Plants for use with the Catchment Management System. Version 1.1. Division of Forest Science and Technology CSIR, Jonkershoek Forestry Research Centre, Stellenbosch. Macdonald, I.A.W., Clark, D.L. and Taylor, H.C. (1987) The alien flora of the Cape of Good Hope Nature Reserve. S. Afr. J. Bot. 53,398-404. Moll, E.J. and Bossi, L. (1984) Assessment of the natural vegetation of the fynbos biome of South Africa. S. Afr. J. Sci. 80, 355-8. Moll, E.J., McKenzie, B., McLachlan, D. and Campbell, B.M. (1978) A mountain in a city-the need to plan the human usage of the Table Mountain National Monument, South Africa. Biol. Conserv. 13, 117-31. Rebelo, A.G. (1992) Preservation of biotic diversity. In The Ecology of Fynbos: Nutrients, Fire and Diversity (R.M. Cowling, ed.) pp. 309-44. Cape Town: Oxford University Press. Threats to biodiversity on the Cape Peninsula Rebelo, A.G. and Siegfried, W.R. (1990) Protection of fynbos vegetation: ideal and real-world options. Biol. Conserv. 54,17-34. Richardson, D.M. and Brown, P.J. (1986) Invasion of mesic mountain fynbos by Pinus radiata. S. Afr. J. Bot. 52,529-36. Richardson, D.M. and van Wilgen, B.W. (1986) The effects of fire in felled Hakea sericea and natural fynbos and implications for weed control in mountain catchments. S. Afr. For. J. l39,4-14. Richardson, D.M., Macdonald, I.A.W. and Forsyth, G.G. (1989) Reductions in plant speciesrichness under stands of alien trees and shrubs in the fynbos biome. S. Afi. For. J. 149,1-8. Richardson, D.M., Macdonald, I.A.W., Holmes, P.M. and Cowling, R.M. (1992) Plant and animal invasions. In The Ecology of Fynbos: Nutrients, Fire and Diversity (R.M. Cowling, ed.) pp. 271-308. Cape Town: Oxford University Press. Richardson, D.M., Van Wilgen, B.W., Le Maitre, D.C., Higgins, K.B., and Forsyth, G.G. (1994) Using computer technology in fire management: an example from the mountain catchment areas of the Cape Province, South Africa. Int. J. Wildl. Fire 4,17-32. Richardson, D.M., Macdonald, I.A.W., Hoffman, J.H. and Henderson, L. (1996). Alien plant invasions. In Vegetation of Southern Africa (R.M. Cowling, D.M. Richardson and S.M. Pierce, eds). Cambridge: Cambridge University Press. (in press). Rourke, J.P. (1980) The Proteas of Southern Africa. Johannesburg: Pumell. Scott, D.F. and van Wyk, D.B. (1990) The effects of wildfire on soil wettability and hydrological behaviour of an afforested catchment. J. Hydroll21,239-56. Scott, D.F., Le Maitre, D.C. and van Wilgen, B.W. (1991) Report on the Problems Relating to the Fire Site on Devil’s Peak and Proposals Toward their Solution. Report C-72, CSIR Division of Forest Science and Technology, Pretoria. Simmons, M.T. and Cowling, R.M. (1996) Why is plant diversity so high on the Cape Peninsula? An analysis of the independent diversity components. Biodiv. Conserv. 5,551-73. Trinder-Smith, T.H., Cowling, R.M. and Linder, H.P. (1996a) Profiling a besieged flora: endemic and threatened plants of the Cape Peninsula, South Africa. Biodiv. Consent. 5,575-89. Trinder-Smith, T.H., Lombard, A.T. and Picker, M. (1996b) Reserve scenarios for the Cape Peninsula: high, middle and low road options for conserving the remaining biodiversity. Biodiv. Conserv. 5,649-69. van Wilgen, B.W. (1987) Fire regimes in the fynbos biome. In Disturbance and the Dynamics of Fynbos Biome Communities (R.M. Cowling, D.C. Le Maitre, B. McKenzie, R.P. Prys-Jonesand B.W. van Wilgen, eds) pp. 6-14. South African National Scientific Programmes Report 135. Pretoria: Foundation for Research Development. van Wilgen, B.W. (1996) Management of the natural ecosystems of the Cape Peninsula: Current status and future prospects. Biodiv. Conserv. 5,671-84. van Wilgen, B.W., Trollope, W.S.W. and Everson, C.S. (1990) Fire management in southern Africa: some examples of current objectives, practices and problems. In Fire in the Tropical Biota: Ecosystem Processes and Global Challenges (J.G. Goldammer, ed.) pp. 179-215. Berlin: Springer-Verlag. van Wilgen B.W., Bond, W.J. and Richardson, D.M. (1992) Ecosystem management. In The Ecology of Fynbos: Nutrients, Fire and diversity (R.M. Cowling, ed.) pp. 345-71, Cape Town: Oxford University Press. Wood, J., Low, A.B., Donaldson, J.S. and Rebelo, A.G. (1994) Threats to plant species diversity through urbanization and habitat fragmentation in the Cape Metropolitan Area, South Africa. Strelitzia 1, 259-74. Richardson et al. Ericaceae Eriospermaceae Fabaceae Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica amoena annectens blancheann capensis capitata clavisepala crenata cyrilliflora ebumea empetrina fairii ferrea fontana genistifolia gilva haematocodon heleogena inops limosa margaritacea marifolia nevillei paludicola patersonia physodes pilulifera pulchella pulchella var. major pyxidifora quadrisulcata salteri sociorum turgida uma-viridis Eriospermum Eriospermum Aspalathus pumilum stoloniferum borboniifolia endemic, threatened endemic, threatened endemic, threatened endemic, threatened threatened endemic, threatened endemic endemic, threatened endemic, threatened endemic endemic, threatened threatened endemic, threatened endemic endemic, threatened endemic rare, threatened endemic endemic, threatened threatened endemic, threatened endemic endemic, rare, threatened rare, threatened endemic endemic, threatened endemic endemic, rare, threatened endemic endemic, rare, threatened endemic, rare, threatened endemic, rare, threatened endemic, rare, threatened endemic rare, rare, threatened threatened endemic, rare, 11 10 6 12 13 10 12 7 8 10 7 17 11 10 6 10 2 10 6 4 11 8 1 4 11 7 6 18 23 4 5 4 2 3 4 5 3 0 0 2 3 0 0 3 2 4 5 6 3 0 0 2 3 0 0 3 3 4 5 6 3 0 0 2 3 0 0 3 2 0 1 5 1 5 0 0 0 0 0 0 4 0 0 0 0 0 3 2 0 0 0 0 0 0 4 0 1 0 0 0 3 2 0 0 0 0 0 0 4 1 2 0 0 0 3 2 0 0 0 0 0 3 threatened 4 10 9 2 % 50 1 8 1 “a 106 3 2 0 0 0 0 2 4 4 6 1 f . s s 0 3 4 2 1 3 g Appendix Family 1. (Continued) Species Status Aspalathus Aspalathus Aspalathus Aspalathus Cyclopia Cyclopia Melolobium Priestleya Priestleya Priestleya Psoralea capitata globulosa humilis macrantha buxifolia cape&s aethiopicum angustifolia laevigata tomentosa glaucina ellaphieae of species Total number 1 km’ squares endemic, threatened rare, threatened endemic. rare, threatened threatened endemic, rare, threatened endemic, rare, threatened threatened rare, threatened threatened endemic, threatened endemic, rare. threatened Geraniaceae Pelargonium Haemodoraceae Dilatris corymbosa rare, endemic threatened Hyacinthaceae Drimia Drimia duthieae minor rare. rare. Iridaceae Bobartia gladiata var. major Gladiolus aureus Gladiolus bonaespet Gladiolus jonquilliodorus Gladiolus monticola Gladiolus ornatus Gladiolus pillansii var. roseus Gladiolus quadrangulus Gladiolus vigilans Moraea aristata Moraea elsiae Watsonia tabularis Witsenia maura (possibly threatened threatened endemic, rare, threatened endemic. rare. threatened endemic, threatened rare, threatened endemic endemic, threatened rare, threatened threatened rare. threatened endemic, rare, threatened threatened endemic rare, threatened extinct) of Number of 1 km* squares affected three scenarios of urbanization under Present situation (1994) Scenario Ul Scenario u2 Scenario u3 12 2 4 11 1 2 7 1 3 6 2 6 0 0 0 0 2 3 1 2 1 0 6 0 0 0 0 2 3 1 2 1 0 6 0 0 0 0 2 3 1 2 1 0 8 0 0 0 0 2 4 1 2 1 1 3 0 0 3 17 3 7 9 1 3 0 0 0 0 0 1 2 4 14 3 13 20 1 6 4 1 10 23 8 0 0 0 2 4 7 0 0 0 0 5 6 5 0 2 4 2 3 6 19 1 4 3 0 b 16 6 2 4 7 0 0 1 0 5 8 5 z 23. $ 2 5 Mesembryanthemaceae Oxalidaceae Dorotheanthus apetalus Lampranthus dunensis Ruschia filamentosa Ruschia promontorii Ruschia rubricaulis Scopelogena vereculata rare, threatened rare, threatened endemic, threatened endemic, threatened endemic, threatened endemic, rare, threatened 5 2 8 I 6 4 1 1 4 0 1 3 1 1 5 0 1 3 3 1 5 0 1 3 4 1 8 1 6 3 Acrolophia bolusii Acrolophia ustulata Corycium excisum Disa bodkinii Disa ocellata Disa salteri Disa tenella ssp. tenella Disa tenuis Disperis bodkinii Herschelianthe forficaria Herschelianthe purpurascens Herschelianthe venusta Holothrix mundii Monadenia densiflora Monadenia pygmaea Monadenia sabulosa Pachites bodkinii Pterygodium connivens Satyridium rostraturn Satyrium carneum Satyrium foliosum Schizodium obliquum threatened rare, threatened threatened threatened rare, threatened endemic, threatened rare, threatened threatened rare, threatened rare, threatened threatened threatened threatened endemic rare, threatened rare, threatened rare, threatened endemic, rare, threatened rare, threatened threatened threatened threatened 12 2 4 I 4 5 1 13 5 2 6 6 I 13 3 2 1 2 4 10 6 21 11 2 0 0 0 3 0 4 0 0 0 1 1 6 0 0 1 1 4 3 1 4 12 2 0 0 0 3 0 4 0 0 0 1 1 6 0 0 1 1 4 3 1 4 12 2 0 0 0 3 0 4 0 0 0 1 1 6 0 1 1 1 4 3 1 5 12 2 Oxalis rare, natans Poaceae Pentaschtstis papillosa Polygalaceae Muraltia Proteaceae Diastella proteoides Leucadendron argenteum Leucadendron floridurn Leucadendron levisanus Leucadendron macowanii comptonii threatened endemic endemic, threatened threatened threatened threatened rare, threatened endemic, rare, threatened 1 2 2 $ 6 SY ,k” 7’ 3 s 00 s 4 B 0 I 2 1 4 4 4 9 2 1 1 1 4 4 4 10 4 0 0 0 19 1 2 8 6 2 3 6 5 14 11 3 3 1 6 1 1 3 1 8 3 1 2 % *tl s 2’ E F Appendix Family 1. (Continued) Species Status of species Total number 1 km’ squares of Number of 1 km’ squares affected three scenarios of urbanization ---------------~______ Present situation (1994) Restionaceae Rosaceae Rutaceae Scenario Ul Scenario u2 under Scenario u3 Leucadendron srrobilinum Mimetes fimbriifolius Mimetes hirtus Serruria collina Serruria cyanoides Serruria decumbens Serruria foeniculaceu Serruria glomerata Serruria hirsuta Serruria inconspicua Serruria villosa endemic endemic threatened endemic, threatened threatened threatened rare, threatened endemic endemic, threatened rare, threatened endemic 15 16 8 15 11 10 8 22 5 2 38 3 3 3 8 6 3 5 5 3 0 10 5 4 3 8 6 3 5 8 3 0 I1 7 10 6 11 6 5 6 18 5 2 24 Chondropetalum rectum Elegia fenestrata Elegia prominens Elegia verrauxii Hypodiscus rugosus Restio communi.r Restio dodii Restio harveyi Restio micans Thamnochortus fraternus Thamnochortus nutans Thamnochortus punctatus Willdenowia affinb rare, threatened threatened threatened threatened rare, threatened endemic, threatened endemic. threatened rare, threatened rare, threatened threatened endemic. threatened rare, threatened endemic, rare, threatened 3 6 7 3 2 10 4 12 3 12 5 3 1 0 0 1 1 0 0 0 0 1 3 1 0 1 0 0 2 1 0 0 0 0 1 3 1 0 1 1 3 6 3 2 5 0 0 1 6 4 3 1 Cliffortia Cliffortia Cliffortia Chffortia rare, threatened threatened endemic rare. threatened 5 7 0 0 2 0 0 0 2 0 I 1 4 2 21 10 10 Agathosma carinata cymbifolia ericifolia intermedia lanceolata endemic. threatened 3 1 0 II B 3 3 8 Fi Pi E Agathosma Scrophulariaceae pulchella endemic, threatened 3 3 3 3 3 4 8 0 1 0 1 0 2 2 7 Harveya squamosa Polycarena capitata rare, threatened threatened Selaginellaceae Selaginelia pygmaea threatened 11 0 1 3 7 Sterculiaceae Hennannia Hermannia Hermannia micrantha procumbens rudis endemic, rare, threatened endemic, threatened threatened 5 6 13 1 0 3 2 0 3 2 0 5 3 1 10 Thymelaeaceae Passerina TOTAL paludosa endemic, rare, threatened 3 1170 1 1 1 2 273 (23.3%) 314 (26.8%) 343 (29.3%) 669 (57.2%) 2 3 8 B t?I :: 7. 3 2. k s $ h Appendix 2. The impact of three scenarios relating to urbanization and four scenarios relating distribution of 38 native Proteaceae taxa on the Cape Peninsula (+ = endemic: # = threatened: Species Total number of localities Number of localities affected under three scenarios relating to urbanization Present Aulax cancella~a Brobejum stellatifolium Diastella divaricnta D. proteoides* Leucadendron L. coniferurn L. floridum’ L. L. L. L. L. L. argenreum’ laureolum levi.wnuF macowanii+x’ rubrum salignum spissifolium L. strobilinum’ L. xanthoconus Leucospermum conocarpodendron L. hypophyllocnrpodendron Mimetes cucullatuc sc.u2 sc.u3 0 1s of localities affected tfl invasive plants Present situation under four SC. A2 SC. A3 0 0 3 8 20 128 0 8 4 36 210 4 4 4 4 4 4 29 4 4 4 44 2 4 26 2 2 7 33 0 0 3 0 0 0 3 1 8 47 186 I 14 S 5 5 5 5 5 0 0 2 4 0 5 0 377 5 4 79 5 2 5 0 0 0 0 0 17 2x 89 232 17 1 33 210 3 4 0 8 ‘2 4 44 4 4 33 2 3 0 378 20 48s 10 I 1 4 100 2 3 3 522 24 37 112 31 569 38 89 275 41 46 0 4 34 I 11 5 I) 8 1 0 5 22 130 38 P. P. P. P. P. P. 37.5 15 180 4 8 36 0 5 4 15 9 328 II u 13 27 56 6 0 8 1 0 I 2 0 3 s 22 IO I 21 60 6 9 I 2 1 1X 27 100 72 20 g scenarios 0 0 8 0 0 7 0 4 306 P. scolymocephalu Sc.Ul Number relating and spread on the SC. Al 3 M. fimbriifolius. M. hirtus” Protea ncaulos P. aurea P. burchellii P. coronata cynaroides grandiceps lepidocarpodendron nitida repens speciosa situation to invasive alien plant control * = rare) SC. A4 4 1 0 147 I 2 7 84 16 2.5 62 516 19 35 52 567 0 0 6 46 0 12 38 2 2 10 53 306 0 n 2 15 8 51 180 4 0 5 4 1 0 5 1 0 5 11 53 9 1 19 1 51 58 5 483 10 8 36 362 13 Pa E. z 328 & !? IS 28 93 4 62 15 4 24 236 92 173 2 21 11 22 6 2s 172 2 39 3 15 31 3 17 39 E 240 25 6 II I Serruria collina’x S. cyanoides’ ’ S. decumbem” S. fascifora S. glomerata’ S. hirstua” S. villosa’ TOTAL 10 20 4 26 67 16 151 4585 0 2 0 3 6 0 0 0 2 0 3 6 0 1 131 (2.9%) 209 (5.6%) 0 6 0 4 8 1 10 528 .(11.5Xm) 0 9 2 7 64 6 104 1839 (40.1%) 0 2 0 3 8 0 2 0 2 0 3 6 0 0 0 2 0 3 6 0 3 3 8 2 4 8 2 21 10 20 4 25 67 16 1.51 263 (5.7%) 131 (2.9%) 236 (5.1%) 821 (17.9%) 4536 (98.9%) 2 3 8 6 SY B 7. s c$ s it 2 B 'a 9 2' s Appendix 3. The impact of four scenarios relating to invasive alien trees and shrubs on 161 endemic. rare and threatened plant taxa on the Cape Peninsula. Localities were mapped at a resolution of l-km* squares; a locality was considered affected if dense stands of alien plants occur in that sauare. Nomenclature follows the Bolus Herbarium, University of Cape Town Family Species Status of species Total number 1 km’ squares Apium Asreraceae Athonasia capitata Cot&a myriophylloides inundatum Gerbera wrightii Senecio foeniculoides Stoebe roosea Ursinia Brassicaceae Bruniaceae tenuifolia Heliophila cinerea Heliophila Heliophila pusiNn tabularis Audouinia capitata rare. threatened threatened endemic, threatened endemic. threatened threatened endemic rare, threatened endemic, endemic endemic. threatened rare. threatened Number relating of 1 km’ squares affected to invasive uiants under four scenarios Present situation Scenario Al Scenario A2 Scenario A3 Scenario A4 3 1 1 1 1 2 10 5 14 S 13 16 2 1 2 0 4 3 2 0 0 0 4 3 3 1 0 0 4 3 4 1 1 0 4 4 6 6 I 1 4 0 1 4 0 2 4 1 3 4 1 12 5 9 II 5 2 4 9 4 1 4 9 4 2 4 9 4 2 4 Y Apiaceae of Staavia dodii Staavio dregeana Staavia glutinosa rare. threatened endemic, threatened rare, threatened endemic, threatened Campanulaceae Roella goodiana Wahlenbergia ciliolata endemic. rare. threatened threatened (possibly extinct) 2 6 1 3 0 3 0 3 2 3 Cyperaceae Ficinio micrantha Ficinia pygrnaea lsolepis inconspicun Schoenoxiphium ecklonii Scirpus delicatulus Terraria brachyphylla Terraria compacta Tetraria paludosa Trianoptiles solitariu Trianoptiles stipitata endemic. rare. threatened rare. threatened rare. threatened threatened rare, threatened endemic, threatened threatened endemic, rare. threatened rare. threatened threatened 2 1 1 8 2 8 6 2 3 1 2 1 1 3 0 I I 0 0 0 2 1 1 3 0 0 1 II 0 0 2 I 1 3 0 0 2 0 0 I) 2 1 1 3 0 1 2 0 0 n Errco amoenn endemic. II : Ericaceae threatened % IQ 2 6 6 1 1 i! 2 Y 7 Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erica Erico Erica Erica Erica annectens blancheana cape&s capitata clavisepala crenata cyrilliflora eburnea empetrina fairii ferrea fontann genistifolia gilva haematocodon heleogena inops limosa margaritacea marifolia nevillei paludicola patersonia physodes pilulifera pulchella pulchella var. major pyxidipora quadrisulcata salteri sociorum turgida urna-viridis Eriospermaceae Eriospermum Eriospennum Fabaceae Aspalathus pumilum stoloniferum borboniifolia endemic, threatened endemic, threatened endemic, threatened threatened endemic, threatened endemic endemic, threatened endemic, threatened endemic endemic, threatened threatened endemic, threatened endemic endemic, threatened endemic rare, threatened endemic endemic, threatened threatened endemic, threatened endemic endemic, rare, threatened rare. threatened endemic endemic, threatened endemic endemic, rare, threatened endemic endemic, rare, threatened endemic, rare, threatened endemic, rare, threatened endemic, rare, threatened endemic 3 4 5 3 0 0 2 3 1 0 3 1 1 0 6 1 5 2 1 1 0 0 0 0 0 4 1 3 1 0 0 3 2 3 4 5 3 0 0 2 3 0 0 3 1 0 0 4 1 5 1 1 0 0 0 0 0 0 4 0 0 0 0 0 3 2 rare. threatened rare, threatened 1 0 1 0 3 1 endemic, 1 0 4 rare, threatened 10 6 12 13 10 12 I 8 10 7 17 11 10 6 10 2 10 6 4 11 8 1 4 11 I 6 18 23 4 1 1 5 4 4 5 6 3 0 0 2 4 0 0 3 1 0 1 5 1 5 1 1 0 0 0 0 0 0 4 0 1 0 0 0 3 2 4 5 6 3 0 0 3 4 1 0 3 2 0 2 5 1 5 1 1 0 2 0 0 1 0 4 2 2 0 0 0 3 2 10 6 12 12 10 s t2 s 10 7 8 10 7 6 5 8 ? 3 $. k 16 s 11 9 6 ff n 10 2 10 6 4 11 8 1 4 11 6 6 18 22 4 1 1 5 4 “cr s. $ s Ei Appendix 3. (Continued) Family Species Status of species Total number I km2 squares Asp&thus capitata Aspalathus globulosa Aspalathus humilis Aspalathus macrantha Cyclopia buxifolia Cyclopia capensis Melolobium aethiopicum Priestleya angustifolia Priestleya laevigata Priestleya tomentosa Psoralea glaucina endemic, threatened rare, threatened endemic, rare. threatened threatened endemic, rare, threatened endemic. rare, threatened threatened rare, threatened threatened endemic, threatened endemic, rare. threatened Geraniaceae Pelargonium rare. threatened Haemodoraceac Dilatris corymbosa endemic Hyacinthaceae Drimia Drimia duthieae minor rare. threatened rare, threatened Iridaceae Bobartia Gladiolus Gladiolus Gladiolus Gladiolus Gladiolus Gladiolus Gladiolus Gladiolus Moraea Moraea Wats&a Wits&a Mesembryanthemaceac ellaphieae gladiata Imar. major aureus bonaespei jonquilliodorus monticola omatus pillanrii \‘ar. rose~~.~ quadrangulus vigilans aristata &tie tabularis maura Dorotheanthus Lampranthus apetalus dunenns (possibly endemic, rare, threatened endemic. rare. threatened endemic. threatened rare. threatened endemic endemic, threatened rare, threatened threatened rare, threatened endemic, rare. threatened threatened endemic rare, threatened rare. threatened rare. threatened 12 2 4 11 1 Number relating of 1 km2 squares affected to invasive plants Present situation Scenario Al 6 0 2 0 0 2 3 1 2 1 6 0 0 0 0 2 3 1 2 1 0 Scenario A2 under four scenarios Scenario A3 Scenario A4 6 0 6 0 0 0 0 0 2 3 1 2 1 0 0 0 0 2 3 1 2 1 0 2 0 0 0 17 7 3 6 7 1 3 0 1 0 0 0 0 0 0 2 4 14 3 13 20 1 6 4 1 10 23 8 1 0 0 0 2 4 9 0 0 0 0 6 10 5 0 0 2 4 7 0 0 0 0 5 6 5 0 1 1 2 4 7 0 0 1 0 1 1 2 5 8 0 1 2 6 4 0 5 x 5 0 6 9 5 1 8 22 8 5 2 I I 1 3 I 2 7 1 3 6 2 extinct) of 3 I 2a R’ s Orchidaceae Ruschia filamentosa Ruschia promontorii Ruxhia rubricaulis Scopelogena vereculata endemic, endemic, endemic, endemic. threatened threatened threatened rare, threatened 8 1 6 4 5 0 2 3 4 0 1 3 Acrolophia Satyrium carneum Satyrium foliosum Schizodium obliquum threatened rare, threatened threatened threatened rare, threatened endemic, threatened rare, threatened threatened rare, threatened rare, threatened threatened threatened threatened endemic rare, threatened rare, threatened rare, threatened endemic. rare, threatened rare, threatened threatened threatened threatened 12 2 4 7 4 5 1 13 5 2 6 6 7 13 3 2 1 2 4 10 6 21 12 2 0 0 0 3 1 4 0 1 0 1 1 7 0 1 1 1 4 3 1 4 11 2 0 0 0 3 0 4 0 0 0 1 1 6 0 0 1 1 4 3 1 4 12 2 0 0 0 3 0 4 0 0 0 1 1 6 0 0 1 1 4 3 1 4 Oxalis rare, threatened 4 0 0 0 4 19 3 1 2 19 6 2 2 3 6 6 5 14 11 3 1.5 4 1 6 3 2 4 3 1 6 1 1 2 bolurii Acrolophia ustulata Corycium excisum Disa bodkinii Disa ocellata Disa salteri Disa tenella ssp. tenella Disa tenuis Disperis bodkinii Herschelianthe forficaria Herschelianthe purpurascens Herschelianthe venusta Holothrix mundii Monadenia densijlora Monadenia pygmaea Monadenia sabulosa Pachites bodkinii Pterygodium conniveus Satyridium rostratim Oxalidaceae notans Pentaschistis papillosa Polygalaceae Muraltia Proteaceae Diastella proteoides Leucadendron argenteum Leucadendron floridurn comptonii Leucadendron Leucadendron Leucadendron levisanus macowanii strobilinum endemic. threatened threatened threatened threatened rare, threatened endemic, rare, threatened endemic 12 2 0 0 6 3 0 4 0 1 0 1 2 6 0 1 1 1 4 3 1 5 2 1 2 4 10 6 20 6 5 12 11 3 14 E Appendix Family 3. (Continued) % OY Status of species Species Mimetesfimbriifolius Mimetes hirtus Serruria collina Serruria cynnoides Restionaceae Serruria Serruria Serruria Serruria Serruria decumbens foeniculacea glomerata hirsuta inconspicua Serruria villosa endemic threatened endemic, threatened threatened threatened rare, threatened endemic endemic, threatened rare, threatened endemic Thamnochortus punctatus Willdenowia offinis rare, threatened threatened threatened threatened rare. threatened endemic, threatened endemic, threatened rare. threatened rare. threatened threatened endemic. threatened rare, threatened endemic, rare. threatened Cliffortia Cliffortia Cliffortia Cliffortia rare. threatened threatened endemic rare. threatened Chondropetalum rectum Elegia fenestrata Elegio prominens Elegia verrauxii Hypodiscus rugosus Restio communis Restio dodii Restio harveyi Restio micans Thamnochortus Thamnochortus Rutaccar Agathosma Agathosma Scrophularsxrae llaryya fraternus nutans corinata cymbifoliu ericifolia intermedia lanceolata pulchella squamosrr endemic, endemic. threatened threatened rare. threatened Total number I kmL squares 16 8 15 11 10 8 22 5 2 38 6 7 3 2 10 4 12 s I2 5 3 1 5 2 21 of Number relating of 1 km’ squares affected to invasive plants four scenarios Present situation Scenario Al 2 4 9 2 3 7 4 2 5 5 1 0 Y 3 3 8 6 3 5 5 3 0 11 4 3 8 8 4 5 8 3 0 13 16 8 15 11 10 8 21 5 2 31 0 0 0 0 0 1 0 0 I) 0 1 3 1 n I 0 0 1 1 0 0 0 0 I 3 1 0 1 0 0 2 1 0 1 0 0 1 4 1 0 1 2 6 0 0 2 0 0 0 2 0 0 0 2 0 9 3 10 3 10 3 18 0 (I 0 4 3 2 0 Scenario A2 under Scenario A3 Scenario A4 3 2 10 3 11 12 5 3 1 w .- Polycorena capitata threatened 8 1 1 Selaginellaceae Selaginella pygmoea threatened 11 2 0 Sterculiaceae Hermmnia Hennannia Hermonnia endemic, rare, threatened endemic, threatened threatened 5 6 13 1 0 5 1 0 3 Thymelaeaceae Posserim 3 1 1 349 (29.8%) 273 (23.3%) TOTAL micrantha procumbem rudtk paludosa endemic, rare, threatened 1170 317 (27.1%) 375 (32.1%) 1130 (96.6%) (D 2 3 s 2 n