Vivero, J.L., Ensermu, K. & Sebsebe, D. (2006). Progress on the Red List of plants of Ethiopia and Eritrea: conservation and biogeography of endemic flowering taxa. In: S.A. Ghazanfar & H.J. Beentje (eds), Taxonomy and ecology of African plants, their conservation and sustainable use, pp. 761–778. Royal Botanic Gardens, Kew. PROGRESS ON THE RED LIST OF PLANTS OF ETHIOPIA AND ERITREA: CONSERVATION AND BIOGEOGRAPHY OF ENDEMIC FLOWERING TAXA JOSE LUIS VIVERO 1, ENSERMU KELBESSA 2 & SEBSEBE DEMISSEW2 1 C/Juan de Mena 12, 1-1, Córdoba, Spain National Herbarium, P.O. Box 3434, Addis Ababa, Ethiopia 1 joseluisvivero@gmail.com; 2 ensermu@bio.aau.edu.et; 2 sebsebed@bio.aau.edu.et 2 Abstract A first assessment of threat to the endemic flowering plants of Ethiopia and Eritrea is made, and their biogeography is outlined. This is based on the published accounts of the Flora of Ethiopia and Eritrea (FEE), unpublished manuscripts, bibliography and collections at the National Herbarium (ETH). This information includes data on the taxonomic status, chorology, and ecology of the endemic plants. We have applied the IUCN categories, A1cd, B1ab and B2ab (i, ii, iii, iv) to 596 taxa using the most conservative approach due to the scanty information available. The resulting new Red List contains 464 threatened taxa (CR, EN, VU), three times more than the previous 1997 Red List (an increase of 435 new taxa). Overall endemism is 9.7%, and species endemic to a single province represent 38.6% of the endemic flora. More than 200 taxa are found in a single locality, 72 are known only from type material, and 13 taxa have not been collected since the 19th Century; at least seven are presumed to be extinct. These data illustrate the pronounced narrow endemism among the endangered taxa in the region. The floristic regions of Shewa and Gondar have the highest numbers of endemic taxa, Sidamo and Harerge have the highest number of narrow endemics, and Arsi and Shewa are the most endemic-rich areas. Welo appears as a poor region with only one narrow endemic, the lowest species richness, and with the lowest afroalpine endemic richness (despite having more than 4000 km2 above 3000 m). This coldspot requires further collections and biogeographical research. Gondar and Sidamo have more than half of the total number of endemics (344), reaching up to 70% when Shewa is taken into account. Nine local centres of endemism are specified for Ethiopia, four in the highlands and five in the lowlands. The transitional belt between the Southern Highlands and the Ogaden-Borana lowlands appears as an important endemic plant area, and requires a thorough conservation and chorology assessment. Finally, in light of recent data on plant and animal endemism, we consider the possibility of designating the Horn of Africa as a world hotspot; it has more than 1500 endemic plants, high plant and animal species richness, and an overwhelming habitat modification. Résumé Avancement de la liste rouge des plantes d’Ethiopie et d’Erythrée: conservation et biogéographie des taxons endémiques de spermatophytes. Une première estimation de la menace pesant sur les spermatophytes endémiques d’Ethiopie et d’Erythrée est présentée et des modèles biogéographiques pour les plantes endémiques sont décrits sur base des 761 Taxonomy and ecology of African plants, their conservation and sustainable use volumes publiés de la ‘Flora of Ethiopia and Eritrea’ (FEE), de manuscrits inédits, de la bibliographie et d’échantillons du ‘National Herbarium’ (ETH). L’information rassemblée comprend des données sur le statut taxonomique, la chorologie et l’écologie. Les catégories IUCN, basées sur les critères A1cd, B1ab et B2ab (i,ii,iii,iv) appliqués en utilisant l’approche la plus conservatrice en raison de l’insuffisance d’information, sont affectées à 596 taxons. Cette nouvelle liste rouge contient 464 taxons menacés (CR, EN, VU) et triple la précédente liste établie en 1997 avec une augmentation de 435 taxons. Les espèces endémiques d’une seule province représentent 38,6% de la flore endémique et le pourcentage d’endémisme est de 9,7%. En fait, plus de 200 taxons ne sont présents que dans une seule localité, 73 sont seulement connus de l’échantillon-type et 14 n’ont plus été récoltés depuis le XIXème siècle, huit au moins ayant probablement disparu. Ces données illustrent le stenoendémisme prononcé parmi les taxons menacés de la région. Shewa et Gondar sont les régions floristiques avec le plus grand nombre de taxons endémiques, Sidamo et Harerge ont les valeurs les plus élevées en terme d’endémisme à petite échelle, alors que Arsi et Shewa viennent en tête en ce qui concerne la richesse endémique par région. Wello, au contraire, se révèle une région anormalement pauvre avec un endémisme à petite échelle, la richesse spécifique la plus faible et la richesse en endémiques afroalpines la plus basse (malgré le fait qu’elle comprend plus de 4000 km2 au-delà de 3000 m d’altitude). Ce ‘coldspot’ nécessite des missions de récolte et des recherches biogéographiques complémentaires. Gondar et Sidamo totalisent plus de la moitié des endémiques (344), atteignant jusqu’à 70% lorsque Shewa est pris en compte. Neuf centres locaux de plantes endémiques sont indiqués pour l’Ethiopie, quatre dans les régions d’altitude et cinq à basse altitude. La zone de transition entre les ‘Southern Highlands’ et les terres basses de Ogaden-Borana semble être une région importante d’endémisme végétal. Une conservation minutieuse et une évaluation de la chorologie par un important travail de terrain sont considérés de la plus haute importance pour terminer l’établissement des listes rouges. Finalement, à la lumière des données récentes sur les endémiques animales et végétales, les auteurs discutent de l’égilibilité de la corne de l’Afrique en tant que ‘hotspot’ mondial avec plus de 1500 plantes endémiques, une richesse spécifique animale et végétale élevée et une modification inquiétante de l’habitat. Key words: conservation, endemism, Ethiopia and Eritrea, hotspot, Red List 1 Introduction The richness of Ethiopia’s biological resources is well-documented. The country exhibits an enormous variety of plants and animals, many of them being endemic to this area (Yalden & Largen, 1992; Hillman, 1993; Fjeldså & Klerk, 2001; Vivero, 2001). Vavilov (1951) indicated that 38 species have their primary or secondary centre in Ethiopia, whereas Zohary (1970) identified 11 cultivated crops as having their centres of diversity in the area. The Flora of Ethiopia and Eritrea (FEE hereafter) area has a truly unique environment for its region and this, together with its isolation, has been a potent stimulus for rapid speciation in its colonists (Kingdon, 1989). Ethiopia, including Eritrea, is considered to be a minor core area for endemism and biodiversity (Harlan, 1969; Hamilton, 1982; Davis et al., 1994). However its importance as a threatened biodiversity hotspot has not been duly acknowledged due to the scanty, outdated and incomplete knowledge about its flora and fauna. Thus, out of the 25 terrestrial hotspots identified by Myers et al. (2000), neither the pair Ethiopia-Eritrea nor the Horn of Africa as a whole have been eligible. Previous studies of the flora of 762 Progress on the Red List of plants of Ethiopia and Eritrea Ethiopia and Eritrea1, always based upon estimations or incomplete species lists, indicate figures ranging between 6000 and 7000 species, with levels of endemism between 12–20% (Cufodontis, 1953–72; Brenan, 1978; Friis, 1983; Tewolde Berhan, 1986, 1991). As a rule, the higher the knowledge about Ethiopian flora, the lower the figure of plant endemic species: 1182 in 1972, 804 in 1986, 596 in this paper. Only partial Red Lists of plants of Ethiopia and Eritrea have been published to date (Oldfield et al., 1998; Walter & Gillett, 1998; Hilton-Taylor, 2000), all of them based on published volumes of FEE or partial lists for afroalpine, endemic or woody taxa (Hedberg, 1957; Viswanathan, 1986; Ensermu et al., 1992; Friis, 1992). Red-listing assessments of the conservation status of all known plant species at national and regional levels are among the sixteen specific outcome-oriented global targets for 2010 of the Global Strategy for Plant Conservation, adopted during the Convention of Biological Diversity COP-6 in The Hague (Simiyu, 2003). The purpose of the present study is twofold: a) to provide a preliminary assessment of the flowering endemic plants of Ethiopia and Eritrea, assigning IUCN categories to the taxa, and b) to outline some biogeographical patterns of the endemic plants of Ethiopia and Eritrea. Finally the authors, in light of the evidence presented in the paper, discuss the consideration of the area as world hotspot, according to the three evaluating criteria used by the international organization Conservation International (Mittermeier et al., 1999). 2 Materials and methods The taxa included in the Red List of Flowering Plants of Ethiopia and Eritrea have been drawn from the published volumes of the Flora of Ethiopia and Eritrea (FEE) Vols. 2 (part I, II), 3, 6, 7 (Hedberg & Edwards, 1989; Edwards et al., 1995, 1997, 2000; Hedberg at al., 2003) and from the manuscripts under preparation for the same flora. These unpublished manuscripts were under different stages of preparation, thereby making necessary in some cases a complementary work to be carried out by the authors and member of the National Herbarium staff to complete the data. Moreover, detailed research on the funds of the National Herbarium of Addis Ababa University (ETH) was conducted to validate areas of occurrence and dubious taxonomic aspects. Other unpublished material was also used to complement the existing data. The nomenclature of the taxa and the floristic regions follow the FEE. Those regions are based on the old administrative regions of imperial Ethiopia, and they have already been used for phytogeographical purposes (Friis et al., 2001; Nordal et al., 2001). Within the Horn of Africa, Ethiopia and Eritrea encompass a homogeneous block, having the high plateau (northern and southeastern) in the middle, surrounded by the savanna lowlands. Thus, although two different sovereign countries since 1994, Ethiopia and Eritrea form one ecological unit and so they will be considered in this paper. Endemism will be therefore assigned to those taxa restricted to the administrative boundaries of both countries. More than 5600 species from 200 families have been reviewed and relevant information has been collected for the endemic flowering taxa. Table 1 shows the number of families and species per volume in the Flora of Ethiopia and Eritrea. For unpublished volumes, the estimations are made based on personal communication from corresponding authors and reviewed manuscripts provided by the Editorial Board. The numbers per volume correspond to species level only. 1 References to Ethiopia before 1993 refer to Ethiopia and Eritrea 763 Taxonomy and ecology of African plants, their conservation and sustainable use TABLE 1. Families and species for published and unpublished volumes of Flora of Ethiopia and Eritrea (estimates based on manuscripts and ongoing research). Volume 2 (part 1) 2 (part 2) 3 4 (part 1) 4 (part 2) 5 6 7 Year of publication Families Species1 2000 1995 1989 2003 2005 in prep. (2006) 1997 1995 61 26 49 13 1 24 38 1 676 687 1097 381 480 946 757 618 200 5642 TOTAL 1 Including additional species described since publication TABLE 2. IUCN categories and criteria assigned to flowering endemic plants of Ethiopia and Eritrea. 2003 Initiative Criteria A B1 B2 1997 Red List CR EN VU NT LC Total Total N° spp % taxa spp 196 135 133 66 66 596 (32.7%) (22.5%) (22.2%) (11%) (11%) 52 19 27 133 71 68 155 76 78 550 Ex Ex/E V R I Total 0 3 69 46 14 163 5642 9.7 N° spp % 6603 2.5 The taxa information included the right citation, chorology, ecology (habitat and altitude) and former IUCN categories. All the taxa were assessed according to the IUCN criteria (IUCN, 2001). To calculate the endemism percentage in the FEE area, all the endemic subspecies have been gathered in the corresponding species level, accounting just for one species. As the first assessment for more than 400 taxa was based on scanty resources and the available information to date, only IUCN criteria A1cd, B1ab and B2ab (i, ii, iii, iv) were applied. The category Extinct has been discarded because consistent information and extensive field work is needed before we can certainly assume a taxon is extinct. Criteria A relates to declining population, with 1c being used when there is an observed, estimated or suspected reduction in the area of occupancy or extent of occurrence; whereas 1d was applied when levels of exploitation were considered as a threat for the species survival. Geographic range size and fragmentation, criteria B, was the most frequently applied, either for severe fragmentation or limited number of locations (1a, 2a) or for continuing decline (1b, 2b). Only the first four qualifiers were used, as the number of mature individuals was 764 Progress on the Red List of plants of Ethiopia and Eritrea unknown. This was considered by the authors the most conservative approach, as information related to other criteria was not available at the time of the study, it was almost absent or it would have required extensive field work. In any case, any person conducting an assessment is expected to use the best available information in combination with inference and projection to test a taxon against the criteria (IUCN, 2003). The IUCN Red List categories are primarily meant to be applied at global level, which happens to be the case in this paper because the taxa are endemic and their range is therefore the global range. Species have been assigned the higher risk categories if known only from a single or few localities, and/or it has not been collected for many years. 3 Results and discussion 3.1 The enlarged Red List of Ethiopia and Eritrea The red listing exercise presented in this paper contains 596 taxa, species and subspecies, what represents more than a threefold increase compared to the previous 1997 Red List of Ethiopian and Eritrean plants (Walter & Gillett, 1998). This new Red List contains 464 taxa in the higher risk categories (CR, EN, VU), with an increase of 392 threatened taxa compared to the 1997 Red List. These threatened taxa, considered as Globally Threatened Plants due to their endemism, represent 8.2% of total flora. This figure is expected to increase once fern and fern allies are reviewed, and especially when near-endemic species are assessed (those also present in neighbouring countries such as Somalia, Sudan and Kenya). As there are 550 species and 46 subspecies in the Red List, and the total figure for the reviewed flowering flora of both countries is 5642 species, the most updated endemism percentage for Ethiopia and Eritrea is 9.7%. This percent may vary slightly when the remaining families are included, but we shall not expect much variation considering the considerable figure of reviewed species. Table 2 summarizes the IUCN categories assigned to each taxon, and the criteria used in each category. There are 137 woody taxa (32 trees and 105 shrubs), that represent 13% of the total woody plants estimation for the FEE area (Demel et al., 2001). Following life forms presented in FEE, the non-woody taxa are distributed as follows: 376 herbs, 57 succulents, 12 climbers, 8 epiphytes, 3 weeds, 2 geophytes and 1 submerged herb. Among the species present in the Red List there are crops (Avena abyssinica), useful trees (Erythrina burana, Boswellia pirottae), spices (Aframomum corrorima), medicinal plants (Pycnostachys abyssinica, Taverniera abyssinica), weeds (Pentaschistis trisetoides, Avena vaviloviana), species not collected for more than 150 years (Blepharis cuspidata, Phagnalon phagnaloides, Leptagrostis schimperiana, Onobrychis richardii), species presumably extinct by human action (Crotalaria boudetii, Crotalaria heterotricha), dubious species (Orthosiphon grandiflorus, Pavonia steudneri), two monotypic endemic genera (Pseudoblepharispermum bremeri and Nephrophyllum abyssinicum), and species restricted to but widely distributed within the FEE area (Acanthus sennii, Echinops longisetus, Satureja paradoxa). The endemic-rich families are Asteraceae (98), Leguminoseae (67), Euphorbiaceae (43) and Poaceae (38), which indicates the importance of semi-arid savanna-like areas in the lowlands and afroalpine moorlands in the mountains as major centres of endemism. Numbers of endemics per family are shown in Table 3. 3.2 Biogeography of endemic flowering plants The study revealed numerous species with extremely narrow distribution (area of occurrence). Species endemic to a single province represent 38.6% of the endemic flora. Actually, more than 200 taxa are just found in one single locality, out of those 72 are only 765 Taxonomy and ecology of African plants, their conservation and sustainable use TABLE 3. The endemic-rich families in FEE. Asteraceae Leguminosae Euphorbiaceae Poaceae Asclepiadaceae Lamiaceae Orchidaceae Aloaceae Acanthaceae Scrophulariaceae Convolvulaceae Cyperaceae Crassulaceae Caryophyllaceae Lobeliaceae Sterculiaceae Iridaceae Hyacinthaceae Portulacaceae Urticaceae Rubiaceae Brassicaceae Ranunculaceae Anthericaeae Asphodelaceae Celastraceae Loranthaceae Vitaceae Boraginaceae Geraniaceae Malvaceae Polygalaceae Rosaceae Araceae Burseraceae 98 67 43 38 31 30 29 27 21 16 14 14 11 8 8 8 7 3 3 3 7 6 6 5 5 5 5 5 4 4 4 4 4 3 3 Urticaceae Aïzoaceae Anacardiaceae Araliaceae Balsaminaceae Callitrichaceae Capparidaceae Combretaceae Commelinaceae Eriocaulaceae Moraceae Passifloraceae Verbenaceae Violaceae Zingiberaceae Alliaceae Amarathaceae Amarylidaceae Chenopodiaceae Guttiferae Hydrocharitaceae Menispermaceae Moringaceae Plantaginaceae Plumbaginaceae Potamogetonaceae Rutaceae Santalaceae Sapindaceae Saxifragaceae Simaroubaceae Tiliaceae Velloziaceae Zygophyllaceae 3 2 2 2 2 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 TABLE 4. Altitudinal distribution of endemic taxa in Ethiopia and Eritrea. Ecological zones (Daniel 1977) Lowlands Bereha Kolla (0–800 m) (801–1500 m) Highlands Mountains Woina Dega Dega Wirch (1,501–2300 m) (2301–3000 m) (>3000m) Restricted to this range 25 28 24 44 52 Total* 44 149 241 67 55 *42 taxa with no altitudinal data and thus the total sample is restricted to 554 766 Progress on the Red List of plants of Ethiopia and Eritrea known from the type specimen and 13 have not been collected since the 19th Century, with at least seven presumably extinct (Crotalaria boudetii, Crotalaria heterotricha, Crotalaria trifoliolata, Kalanchoe angustifolia, Stachys hypoleuca, Cirsium straminispinum, Vernonia buchingeri). Sidamo and Harerge are the provinces with the highest figures and relative weight (% of total taxa present in the province) of stenochorous species, called provincerestricted taxa (see Table 5). These data illustrate the pronounced narrow endemism among endangered taxa in the region, specially in the lowlands. According to the altitudinal distribution shown in Table 4, there are 193 taxa present in the lowlands, with 53 being narrowly restricted; 308 in the highlands up to 3000 m, with 68 restricted to that range; and 52 above 3000 m (afroalpine endemics according to Hedberg, 1957). Shewa (SU) and Gondar (GD) are the floristic regions harbouring the highest numbers of endemic taxa, followed by Sidamo (SD) and Bale (BA). Sidamo and Harerge (HA) have the highest figures of narrow endemics, with Bale and Gondar falling far behind; whereas Arsi (AR) has by far the highest endemic richness per area (see Table 5). It is worth stressing the importance of Arsi as an important area for plant richness harbouring 103 endemic taxa, with 4 montane species restricted to its administrative boundaries (Eriocaulon aethiopicum, Pennisetum thulinii, Trifolium chilaloense, and Bidens microphylla). Welo (WU), on the contrary, appears as an anomalously poor region with only one narrow endemic found in the intermediate belt between the lowlands and the highlands (Indigofera cana), extremely low endemic richness and the lowest taxa richness. More oddly, Welo has the lowest afroalpine endemic richness in the FEE area, despite the fact of having more than 4000 km2 above 3000 m and three peaks above 4000 m, representing 18% of total for FEE area (Yalden, 1983). The explanation could be this apparently coldspot has been overlooked by 19th and 20th Century botanists (Moggi, 1976), but it surely holds an important afroalpine flora yet to be discovered in mountains such as Abune Yosef, Delanta and Amba Farit, and therefore deserves further collecting trips and biogeographical research. Recent research in Abune Yosef has contributed to the taxonomy of afroalpine Senecio (Ortiz & Vivero, 2005). Shewa, with a medium size area and 43% of land above 2000 m, contains more endemic taxa than any other floristic region. Its pivotal position in the core of the FEE area, comprising semi-arid, savanna, highland and afroalpine ecosystems, enables Shewa to become a reservoir of endemic plants as well as highway for afroalpine plant movements (northwards and southwards) and subsequent speciation, as well as displacement along the Rift Valley. That explains why Shewa stands for the second place in plant diversity, just after Sidamo (Friis et al., 2001). Nevertheless, Shewa still lacks protected areas to cover this rich flora (Nordal et al., 2001). Finally, as shown in Table 6, Gondar and Sidamo accumulate more than half of total endemics (344) thus outlining the importance of being centres of endemism, mainly Simien mountains and the V-shape area Moyale-Mega-Yabello and the Liben Plains (see below). The last figure reaches up to 70% (422 taxa) when Shewa is taken into account, thereby demonstrating the importance of the North-South axis through the Highlands as a major centre of endemism in the Horn of Africa, with Shewa at its heart. 3.3 Local centres of endemism Based on the data contained in the Red List of Endemic Flowering Taxa, and finetuning the broad-based figures for each floristic region displayed above, nine local centres of endemism have been considered in Ethiopia and Eritrea. The centres of endemism are specific areas displaying considerable numbers of endemic species, and they are the following: Simien Mountains, Bale Mountains, Agere Maryam-Yabello-Mega and Harerge Highlands in the high plateau, and Liben Plains, Bale Eastern Plains, Jijiga Lowlands, Borana Lowlands and Ogaden Desert in the lowlands. It is not the intention 767 ER AF AR BA GD GG GJ HA IL KF SD SU TU WG WU Total endemic taxa 100 4 103 173 208 59 122 138 47 100 182 229 143 78 58 Area (in 1000 km2) 125.7 85.4 21.5 131.2 80.2 39.5 62.2 261.2 53.5 53.5 111.7 82 60.2 77.2 93.5 Endemic Richness (endemics/10,000 km2) 7.9 0.4 47.9 13.1 25.9 14.9 19.5 5.2 8.7 18.6 16.2 27.9 23.7 10.0 6.2 Taxa Richness2 (species/10,000 km2) 84.4 – 243.2 62.4 107.6 193.4 93.4 42.6 108.2 166.7 127.3 151.8 154.3 72.6 39.3 Province-restricted taxa 15 0 4 27 26 5 4 43 2 4 54 20 21 5 1 % over total province endemics 15 0 3.8 15.6 12.5 8.4 3.2 31.1 4.2 4 29.6 8.7 14.6 6.4 1.7 Province endemic richness (endemics/10,000 km2) 1.2 0 1.8 2.0 3.2 1.2 0.6 1.6 0.3 0.7 4.8 2.4 3.4 0.6 0.1 1 2 Eritrea is treated as a separate unit. Based on Friis et al. (2001) with data from published FEE volumes (2,959 taxa) Taxonomy and ecology of African plants, their conservation and sustainable use 768 TABLE 5. Number of endemic taxa in Ethiopia-Eritrea per administrative provinces 1. Abbreviations for administrative provinces follow FEE. Progress on the Red List of plants of Ethiopia and Eritrea TABLE 6. Cumulative percentage of endemic taxa per different floristic regions pairs. Accumulative % N° endemic species % total endemic species GD-SD SD-SU SU-BA GD-BA GD-SU GD-SU-SD 344 343 319 317 315 422 57.8 57.6 53.5 53.1 52.8 70.5 of this paper to be exhaustive while determining a local-level centre of endemism, but we aim at refining the generally-recognized centres of endemic plants, providing updated figures to help towards formulating conservation strategies, and planning protected areas for these micro-hotspots. Minor local centres of endemism in Tigray, Gojam (Nordal et al., 2003), Ilubabor or Kefa have not been considered in this paper. 3.3.i Bale and Simien Mountains as major afroalpine centres of endemism in Ethiopia There are 55 afroalpine endemic taxa (49 species and 6 subspecies), mostly herbs belonging to Asteraceae (17) and Poaceae (8), which adds 41 taxa to previous accounts (Hedberg, 1994). Gondar and Bale hold the highest numbers, 33 and 27 respectively, as expected by the importance of Simien and Bale Mountains as centres of endemism. However, when considering the afroalpine endemic richness, as the number of endemics per 1000 km2 of area above 3000 m, Tigray stands high with 7 endemics in 350 km2, followed by Gondar and Harerge. Welo however presents the lowest afroalpine endemics density. Simien Mountains harbour nine afroalpine taxa found only in those mountains, whereas Bale has only three. Furthermore both mountains also hold a rich afromontane flora in the Juniperus and Erica woodlands as well as in the lower altitude closed forests. Appendix 1 shows a preliminary list of endemic plants present in those two centres of endemism. Simien Mountains, a World Heritage Site and National Park, stands as the most important centre of endemism for montane and afroalpine plants in Ethiopia, as it has 120 endemic taxa (with 21 plants narrowly restricted to that mountain). Bale Mountains, a National Park widely known for its endemic mammals and the Sanetti Plateau and Harenna Forest, holds 111 endemic plants (with 10 restricted to its limits). Bale Mountains National Parks, with an extension of 4400 km2 and ranging from 1500 m to 4377 m, could be considered as a micro-hotspot, as one can find within its boundaries 18.8% of endemic plants, 26.5% of endemic mammals and 53.3% of endemic birds of Ethiopia and Eritrea. Endemic plant density is over 2.5 taxa per 100 km2. Despite its legal protection, it suffers from a worrisome set of threats to its survival, such as human invasion by refugees, forest fires, illegal grazing, forest encroachment by cultivated land or animal diseases. There are 60 endemic taxa shared by both mountains, with 5 found nowhere else. 3.3.ii Southern Highlands The Agere Maryam-Yabello-Mega centre (1500–2200 m) is confined to a long strip from the highland flat areas near Agere Maryam in the north to the gentle semi-arid slopes in the south. There are 18 taxa restricted to this area (see Appendix 2) distributed along the hills, slopes, Acacia-Commiphora woodlands and grasslands that cover the lower highlands. The only protected area is the Yabello Sanctuary (2540 km2), designed to protect two endemic threatened birds, the Abyssinian Bush Crow and the White-tailed Swallow. 769 Taxonomy and ecology of African plants, their conservation and sustainable use The Harerge Highlands (1500-2800 m) are located between Dire Dawa, Harar and Jijiga and present several minor peaks such as Mount Hakim and Mount Gara-Mulata. There are 14 taxa (see Appendix 2) in this area. The landscape is formed by a combination of dry evergreen montane forests (Juniperus, Olea), with AcaciaCommiphora woodlands and grasslands at lower altitudes. This area is considered as a major centre of endemic Aloe species, where a number of transgressors from lowlands to highlands are found (Sebsebe et al., 2001). The combination of high altitude and low rainfall has acted as a speciation driving force. 3.3.iii South Plains and Southeastern Lowlands The Jijiga Lowlands centre of endemism is formed by relatively flat areas in the lower contour of Jijiga lowlands up to Degeh Bur, between 800–1500 m. It holds the only populations of 11 extremely narrow plants (see Appendix 3). The habitat is largely occupied by Acacia-Commiphora bushland characterised by drought tolerant trees and shrubs, which have either deciduous leaves or leathery persistent leaves. The understorey mainly consists of shrubs, perennial herbs and grasses. Some of these populations could be included within the limits of the gazetted but actually unprotected Babille Elephant Sanctuary. The Bale Eastern Plains, ranging from 1200 to 1600 m, have 13 narrowly restricted taxa (see Appendix 3). This local centre embraces a relatively sharp boundary between the lowlands and the elevated highlands, having suffered dramatic changes in vegetation and climate during the Quaternary. This area, south and south east of Bale Mountains National Park, has been pointed out as the gravitational centre of lilioid geophyte endemics of Ethiopia (Nordal et al., 2001). This area has been fairly inaccessible for quite a while and therefore barely collected. Most collections have been done around S of Omar caves (type locality for 6 endemic taxa, see Appendix 3). This limestone valley is covered with shrubs, small trees (Acacia-Kirkia-Commiphora) and climbers. The Liban Plains are extensive areas of comparatively flat land, lying between the Genale and Dawa rivers (EWNHS, 1996), with Negele woodlands as the northern border and Bogol Mayo as southern limit. The altitude starts at 1000 m at the edge of the Genale river gorge and rises gently to over 2000 m in the forest located on the escarpment. The landscape is formed by Acacia-Commiphora woodland and bushland, with Combretum, Boswellia, Barbeya and Kirkia as common species. Soils can be rocky, calcareous, granitic or limestone. This important local micro-hotspot has 22 endemic taxa (see Appendix 3), plus the only populations of two narrow endemic birds (Degodi Lark and Sidamo Lark). Overgrazing by cattle, human pressure by internal displacement due to ethnic clashes, and recurrent persistent droughts are serious threats to this open area. The road between Negele and Bogol Mayo has been the type locality for at least 10 narrow endemics (marked with * in Appendix 3). The Borana Lowlands centre has the lowest endemic plants (6 taxa seen in Appendix 4), but it has been considered due to its clear distinction from surrounding centres. It lies between 300–1000 m, but it transgresses the Kenyan border and extends to northern Moyale province, thereby comprising many more near-endemic species not included in this Red List. It is covered by open vegetation with scattered shrubs, small trees and annual herbs, and succulents. The Ogaden Desert, consisiting of the greater part of Somalia and the northern strip of Kenya (200–800 m), has been traditionally considered as a regional centre of plant and animal endemism (Kingdon, 1989; Davis et al., 1994). This area is commonly called the Somali-Masai biome. The Ethiopian side contains 27 endemic taxa in Harerge (and Bale) provinces (Appendix 4), with one or few scattered localities for 770 Progress on the Red List of plants of Ethiopia and Eritrea each species. The Ogaden area has been a stable habitat for thousands of years, thus it contains many arid species in the limestone woodlands and shrublands, many of which are endemic. The habitats are mostly defined by rainfall and vegetation types. 4 Conclusions The Red List of Endemic Flowering Plants is of relevance to the biogeography and conservation of the flora of Ethiopia and Eritrea. This preliminary Red List, where only endemics have been assessed, adds considerable taxa to previous lists and accounts: 41 new afroalpine taxa, 115 new Red List trees and shrubs, and 435 new taxa. Nine local centres of endemism are proposed and preliminary endemic plants within their boundaries are listed. There is a remarkable pattern of high endemic density found in three local centres of endemism situated along the southern limit of the Highlands, a transitional area between two phytogeographical zones: the Ethiopian Highlands and the Somali-Masai biome (White, 1983). This transitional zone runs parallel to the Southern Highland block from south to northeast and contains the Jijiga Lowlands, the Bale Eastern Plains and the Liban Plains, and to a lesser extent parts of the Agere Maryam-Yabello-Mega area and the Harerge Highlands. This longitudinal area, ranging between 1000 m and 2000 m, embraces the altitudinal belt where the species richness and endemism is highest in Ethiopia (Friis et al., 2001). Although the work undertaken has been considerable, the remaining activities request a coordinated effort from different research and financial institutions to place the Ethiopian flora on the world map of conservation and biodiversity. Extensive field work needs to be done to collect data chorology and conservation. The near-endemic plants (more than 600) need to be assessed, and the most threatened endemic plants (many of them only known from the type specimen or not collected since 1870) require immediate assessment in the field for implementing conservation measures. We have been recently informed that an ongoing exercise is being carried out by Conservation International to assess the two main biomes present in the Horn of Africa, the Ethiopian Highlands and the Somali-Masai lowlands for their consideration as world hotspots. Based on the information provided in this paper, plus the more than 300 near-endemics shared with Somalia and Kenya and the 600 taxa restricted to Somalia (Thulin, 1994), we could reasonably assume that the Horn of Africa holds more than 1500 endemic plants. The high numbers of endemic species (plants, mammals and birds), the plant richness (more than 7000 species) and the high habitat modification due to natural disasters, civil strife and cattle pressure may entitle for any of those two biomes to be upgraded to the selected group of world’s major hotspots. References Brenan, J.P.M. (1978). Some aspects of the phytogeography of tropical Africa. Ann. Missouri Bot. Gard. 65: 437–478. Cufodontis, G. (1953–72). Enumeratio plantarum Aethiopiae Spermatophyta. Bull. Jard. Bot. Etat Brux. 23–42. Daniel, G. (1977). Aspects of climate and water budget in Ethiopia. Addis Ababa University Press, Addis Ababa. Davis, S.D., Heywood V.H. & Hamilton A.C. (eds). (1994). Centres of Plant Diversity. Vol 1: Europe, Africa, Southwest Asia and Middle East. World Wildlife Fund for Nature and IUCN, Oxford, UK. 771 Taxonomy and ecology of African plants, their conservation and sustainable use Demel, T., Taye, B. & Hasse, G. (2000). Forests and forest genetic resources of Ethiopia. Paper presented to the international conference Ethiopia: a biodiversity challenge. February 2–4, 2000. Addis Ababa University, Addis Ababa and Linnean Society of London, London. Edwards, S., Sebsebe, D. & Hedberg I. (eds). (1997). Flora of Ethiopia ad Eritrea, Vol. 6: Hydrocharitaceae to Araceae. The National Herbarium, Addis Ababa and the Department of Systematic Botany, Uppsala. Edwards, S., Mesfin, T. & Hedberg, I. (eds). (1995). Flora of Ethiopia and Eritrea, Vol. 2, part 2: Canellaceae to Euphorbiaceae. The National Herbarium, Addis Ababa and the Department of Systematic Botany, Uppsala. Edwards, S., Mesfin, T. & Hedberg, I. (eds). (2000). Flora of Ethiopia and Eritrea, Vol. 2, part 1. The National Herbarium, Addis Ababa and the Department of Systematic Botany, Uppsala. Ensermu, K., Sebsebe, D., Zerihun, W. & Edwards, S. (1992). Some threatened endemic plants of Ethiopia. In: S. Edwards & A. Zemede (eds), The status of some plant resources in parts of tropical Africa. Botany 2000: East and Central Africa. NAPRECA Monograph Series no 2. NAPRECA, Addis Ababa University. Fjeldså, J. & de Klerk, H. (2001). Avian endemism in northeastern tropical Africa. Biol. Skr. 54: 259–271. Friis, I. (1983). Phytogeography of the tropical north east African mountains (Ethiopia, Djibouti, Somalia). Bothalia 14: 525–532. Friis, I. (1992). Forest and Forest Trees of Northeast Tropical Africa. Kew Bulletin Additional Series no XV. Friis, I., Edwards, S., Ensermu, K. & Sebsebe, D. (2001). Diversity and endemism in the flora of Ethiopia and Eritrea-what do the published Flora volumes tell us? In: I. Friis & O. Ryding (eds), Proceedings of the 3rd International Symposium on the Flora of Ethiopia & Eritrea. Biol. Skr. 54: 173–193. Hamilton, A.C. (1982). Environmental history of East Africa (a study of the Quaternary). Academic Press, London. Harlan, J.R. (1969). Ethiopia: a centre of diversity. Econ. Bot. 23: 309–314. Hedberg, I. & Edwards, S. (eds). (1989). Flora of Ethiopia and Eritrea, Vol. 3: Pittosporaceae to Araliaceae. The National Herbarium, Addis Ababa and Asmara, and the Department of Systematic Botany, Uppsala. Hedberg, I., Sileshi, N. & Edwards, S. (eds). (2003). Flora of Ethiopia and Eritrea, Vol. 4, part 1: Apiaceae to Dipsacaceae. The National Herbarium, Addis Ababa and the Department of Systematic Botany, Uppsala. Hedberg, O. (1957). Afroalpine vascular plants. A taxonomic revision. Symb. Bot. Ups. 15: 1–411. Hedberg, O. (1994). Afroalpine centres of biodiversity and endemism. In: J.H. Seyani & A.C. Chikuni (eds), Proceedings XIIIth Plenary Meeting AETFAT, Malawi, 2: 877–882. Hillman, J.C. (1993). Ethiopia: a compendium of wildlife conservation information. Vol. I. New York Zoological Society, New York and EWCO, Addis Ababa. Hilton-Taylor, C. (compiler) (2000). 2000 IUCN Red List of threatened species. IUCN, Gland, Switzerland and Cambridge, UK. IUCN (2001). IUCN Red List categories and criteria: version 3.1. IUCN Species Survival Commission, IUCN Gland, Switzerland and Cambridge, UK. IUCN (2003). Guidelines for using the IUCN Red List Categories and Criteria. Prepared by the Standards and Petitions Subcommittee of the IUCN SSC Red List Programme Committee. Gland, Switzerland. 772 Progress on the Red List of plants of Ethiopia and Eritrea Kingdon, J. (1989). Island Africa: The evolution of Africa’s rare animals and plants. Princeton University Press, Princeton, New Jersey. Mittermeier, R.A., Myers, N., Mittermeier, C.G. & Gill, P.R. (1999). Hotspots: Earth’s biologically richest and most endangered terrestrial ecoregions. CEMEX S.A., Mexico DF. Moggi, G. (1976). Aperçu sur la connaissance floristique d’Ethiopie et de Somalie en vue d’une nouvelle édition de la carte du degré d’exploration floristique de l’Afrique. Boissiera 24: 593–596. Myers, N., Mittermeier, R.A, Mittermeier, C.G., Fonseca, G.A.B. & Kent, J. (2000). Biodiversity hotspots for conservation priorities. Nature 403: 853–858. Nordal, I., Sebsebe, D. & Stabbetorp, O.E. (2001). Endemism in groups of Ethiopian geophytes (“Liliiflorae”). In: I. Friis & O. Ryding (eds), Proceedings of the 3rd International Symposium on the Flora of Ethiopia & Eritrea. Biol. Skr. 54: 247–258. Oldfield, S., Lusty, C. & MacKinven, A. (1998). The world list of threatened trees. World Conservation Press, Cambridge. Ortiz, S. & Vivero, J.L. (2005). New species and new combination in the afroalpine Senecio nanus-S. schultzii complex (Asteraceae, Senecioneae). Blumea 50: 191–195. Sebsebe, D., Nordal, I, & Stabbetorp, O.E. (2001). Patterns of endemism of the genus Aloe in the Flora of Ethiopia and Eritrea. In: I. Friis & O. Ryding (eds), Proceedings of the 3rd International Symposium on the Flora of Ethiopia & Eritrea. Biol. Skr. 54: 233–246. Simuyu, S. (2003). The CBD Global Strategy for plant conservation: priorities and opportunities for a concerted red listing effort. Paper presented at the XVII AETFAT Congress, 22–26 September 2003, Addis Ababa, Ethiopia. Tewolde Berhan, G.E. (1986). The conservation and utilization of Ethiopian germplasm. In: Diversity of Ethiopian Flora: Proceedings of International Symposium, Addis Ababa, Ethiopia. Tewolde Berhan, G.E. (1991). Diversity of the Ethiopian flora. In: J.M.M. Engels, J.G. Hawkes & M. Wereda (eds), Plant Genetic Resources of Ethiopia, pp. 75–81. Cambridge University Press, Cambridge. Thulin, M. (1994). Aspects of disjunct distribution and endemism in the arid parts of the Horn of Africa, particularly Somalia. In: J.H. Seyani & A.C. Chikuni (eds), Proceedings XIIIth AETFAT Congress, Zomba, Vol. 2, 1105–1119. Vavilov, N.I. (1951). The origin, variation, immunity and breeding of cultivated plants. Chirinica Botanica 13: 1–366. Viswanathan, T.V. (1986). Endangered tree species in northern Ethiopia. Environ. Conserv. 13: 71–72. Vivero, J.L. (2001). A guide to endemic birds of Ethiopia and Eritrea. Shama Books, Addis Ababa. Walter, K.S. & Gillett, H.J. (eds) (1998). 1997 IUCN Red List of Threatened Plants. WCMC & IUCN-The World Conservation Union, Gland, Switzerland and Cambridge, UK. White, F. (1983). The Vegetation of Africa. UNESCO, Paris. Yalden, D.W. (1983). The extent of high ground in Ethiopia compared to the rest of Africa. Sinet: Ethiopian Journal of Science 6: 35–39. Yalden, D.W. & Largen, M.J. (1992). The endemic mammals of Ethiopia. Mammal Rev. 22: 115–150. Zohary, D. (1970). Centres of diversity and centres of origin. In: O.H. Frankel & E. Bennett (eds), Genetic resources in plants, their exploration and conservation. Blackwell Scientific Publications, Oxford, UK. 773 Taxonomy and ecology of African plants, their conservation and sustainable use APPENDIX 1. Endemic taxa in two important local centres of plant endemism in Ethiopia. Simien Mountains Bale Mountains Both mountains Acacia negrii Agrostis diffusa Aloe percrassa Aloe steudneri Anarrhinum forskaohlii subsp. abyssinicum Anchusa affinis Aphanes bachiti* Argyrolobium schimperianum Astragalus atropilosulus subsp. abyssinicus Becium grandiflorum Ceropegia convolvuloides Ceropegia sobolifera* Chenopodium ulbrichii Cirsium straminispinum Clematis burgensis Clematis longicaudata Convolvulus steudneri Conyza messeri* Crepis achyrophoroides Crepis tenerrima Crotalaria intonsa Cycniopsis humilis Cyperus atronervatus subsp. atronervatus Dianthus leptoloma Disperis galerita Disperis crassicaulis Disperis meirax* Drimia simensis Echinops buhaitensis* Festuca gilbertiana* Festuca macrophylla Galium boreo-aethiopicum Habenaria perbella Habenaria platyanthera* Helichrysum horridum Helichrysum sclerochlaenum Holothrix unifolia Hypagophytum abyssinicum Inula arbuscula* Isolepis omissa Kalanchoe quartiniana Leucas stachydiformis Lobelia schimperi Agrostis gracilifolia subsp. parviflora Alchemilla haumanii Alopecurus baptarrhenius Arisaema mooneyanum Bidens mesfinii* Cineraria abyssinica Crotalaria agatiflora subsp. erlangeri Crotalaria exaltata Cyperus holostigma Chlorophytum ducis-aprutii Droguetia iners subsp. pedunculata* Erucastrum abyssinicum Erucastrum meruense subsp. balense Euphorbia dumalis Euryops antinorii Euryops prostratus* Gladiolus balensis* Gladiolus longispathaceus Haplocarpha hastata Helichrysum elephantinum Helichrysum gofense Helichrysum harennensis Inula confertiflora Justicia schöensis Kanahia carlsbergiana Kotschya recurvifolia subsp. aetiopica Lavatera abyssinica Ledebouria urceolata Lobelia achrochila Lobelia erlangeriana Lobelia scebelii Lobelia tripartita* Maytenus addat Maytenus harenensis* Panicum ruspolii Pentarrhinum balense* Poa hedbergii Rhus glutinosa subsp. neoglutinosa Rubus erlangeri Sedum baleensis* Acanthus sennii Aeollanthus abyssinicus Artemisia schimperi Astragalus atropilosulus subsp. atropilosulus Becium formosum Bidens macroptera Bothriocline schimperi Callitriche favargeri Callitriche hedbergiorum** Chiliocephalum schimperi Chiliocephalum tegetum Cineraria sebaldii Cirsium schimperi Conyza abyssinica Conyza nana** Conyza spinosa Crassocephalum macropappum Cynotis polyrrhiza Echinops longisetus Erophila verna subsp. macrosperma** Erucastrum pachypodum Ficinia clandestina Habenaria lefebureana Herniaria abyssinica** Hyparrhenia arrhenobasis Impatiens tinctoria subsp. abyssinica Kalanchoe petitiana Kalanchoe schimperiana Kniphofia foliosa Kniphofia isoetifolia Kniphofia schimperi Launaea rueppellii Lobelia rhynchopetalum Mikaniopsis clematoides Pennisetum humile Pentaschistis trisetoides Plectocephalus varians Plectranthus garckeanus Poa simensis Polystachya caduca Pseudognaphalium melanosphaerum Ranunculus simensis 774 Progress on the Red List of plants of Ethiopia and Eritrea APPENDIX 1. Continued. Simien Mountains Bale Mountains Both mountains Maytenus cortii* Otostegia tomentosa subsp. steudneri Paronychia bryoides* Pennisetum beckeroides* Pennisetum longistylum Pennisetum uliginosum Phagnalon phagnaloides* Poa pumilio* Polygala rupicola Ranunculus distrias Roeperocharis alcicornis Rosularia semiensis* Rytidosperma grandiflora* Sagina brachysepala* Satureja punctata subsp. ovata Saxifraga hederifolia Sedum epidendron Senecio farinaceus Senecio nanus Senecio pinnatipartitus Snowdenia mutica* Sparmannia macrocarpa Stachys hypoleuca Thymus serrulatus Trifolium bilineatum Trifolium decorum Trifolium mattirolianum Trifolium schimperi Verbascum benthamianum* Verbascum pubescens* Verbascum scabridum* Verbascum sedgwickianum Vernonia buchingeri* Vernonia filigera Vernonia leopoldii Veronica simensis Sedum glomerifolium* Sedum mooneyi Senecio balensis Solanecio harennesis* Stachys alpigena subsp. longipetala Stachys balensis Stolzia grandiflora Tragia ashiae Trifolium spananthum Uebelina kigesiensis subsp. ragazziana Vernonia tewoldei Ranunculus tembensis** Sagina abyssinica subsp. abyssinica Satureja paradoxa Senecio fresenii Senecio myriocephalus Senecio ochrocarpus Senecio schimperi Senecio schultzii Senecio steudelii Senecio unionis Sisymbrium maximum Solanecio gigas Sonchus melanolepis Thalictrum schimperianum Thymus schimperi subsp. schimperi Trifolium calocephalum Urtica simensis Vernonia rueppellii * Restricted to that mountain ** Present on both mountains. 775 Taxonomy and ecology of African plants, their conservation and sustainable use APPENDIX 2. Endemic taxa present in two local centres of plant endemism located in the Southern Highlands. Agere Maryam-Yabello-Mega 1500–2200 m Harerge Highlands 1500–2800 mm Aloe yavellana Asystasia ammophila Athroisma boranense Barleria longissima Bidens zavattarii Conyza megensis Crotalaria sacculata Cyperus costatus subsp. sidamoensis Cystostemon ethiopicus Gladiolus boranensis Hirpicium beguinotii Justicia diclipteroides subsp. megaensis Melhania beguinotti Senecio aequinoctialis Tragia triumfettoides Trifolium somalense Vernonia printzioides Vernonia yabelloana Aloe harlana Aloe megalacantha subsp. alticola Ceropegia ellenbeckii Crotalaria jijigensis Cyphostemma burgeri Euphorbia rubella Gladiolus calcicola Gladiolus lithicola Hildebrandtia diredawaensis Lotus lalambensis Pachycymbium sprengeri subsp. ogadense Pelargonium hararense Rhynchosia erlangeri Stachys jijigaensis 776 Progress on the Red List of plants of Ethiopia and Eritrea APPENDIX 3. Endemic taxa in three centres of plant endemism located in the rich intermediate altitudinal zone of Southern Ethiopia (800–2000 m). Liben Plains 1000–2000 m Bale Eastern Plains 1200–1600 m Jijiga Lowlands 800–1500 m Cladostigma nigistiae* Convolvulus vollesenii* Crotalaria fallax Dicoma aethiopica Endostemon glandulosus Erythrococca uniflora* Euphorbia bittataensis Euphorbia cryptocaulis* Euphorbia ellenbeckii Euphorbia furcatifolia Euphorbia gymnocalycioides Euphorbia uniglans Gladiolus negeliensis* Hibiscus boranensis* Hybanthus puberulus* Jatropha horizontales* Maerua boranensis* Panicum vatovae Phyllanthus borenensis* Polygala mooneyi Ruellia boranica* Wellstedia filtuensis Adenia pulcrha Chlorophytum pterocarppum** Commiphora monoica** Convolvulus gilberti** Crotalaria trifoliolata** Dicoma aethiopica Euphorbia baleensis** Euphorbia omariana** Euphorbia sareciana Hildebrandtia aloysii Melhania somalensis Polygala erlangeri Tragia crenata Ceropegia erergotana Euphorbia burgeri Euphorbia dalettiensis Euphorbia piscidermis Euphorbia somalensis Gutenbergia somalensis Helichrysum jijigaensis Merremia dimorphophylla subsp. ogadensis Rhynchosia ramosa Stylochaeton oligocarpum Vernonia dalettiensis * Road between Negele and Filtu ** Around S of Omar caves area 777 Taxonomy and ecology of African plants, their conservation and sustainable use APPENDIX 4. Endemic taxa of two centres of plant endemism located in semi-arid lower altitudes (below 1000 m). Borana Lowlands 300–1000 m Ogaden Desert 200–700 m Blepharis cuspidata Cadaba divaricata Euphorbia doloensis Euphorbia fissispina Indigofera curvirostrata Justicia vixspicata Acacia bricchettiana Acacia pseudonigrescens* Aloe bertemariae Aneilema grandibracteolatum Boswellia ogadensis Cadaba divaricata Crotalaria boudetii Crotalaria heterotricha Cyperus maculatus subsp. ogadensis Echidnopsis jacksonii Erythrophysa septentrionalis Euphorbia ogadenensis Euphorbia tetracantha* Fagonia hararensis Hermannia erlangeriana Indigofera ellenbeckii Indigofera kelleri Kleinia gypsophila Merremia subpalmata subsp. tenuisecta Merremia warderensis Monadenium shebeliensis Orthosiphon grandiflorus Plicosepalus ogadenensis Pseudoblepharispermum bremeri Pseudolithos gigas Seddera simmonsii Xerophyta rippsteinii* * Bale narrow endemic 778