Identifying Important Plants Areas ( Key Biodiversity Areas for Plants ) in northern Algeria

A study was undertaken in 2010 to identify Important Plant Areas (Key Biodiversity Areas for Plants) in the south and east Mediterranean region, in order to prioritise the best sites for plant conservation action. It follows a first work of identification of Important Plant Areas (IPAs) initiated for Algeria and relates exclusively to the flora of northern Algeria. These IPAs were delineated in northern Algeria for those sites harbouring a number of “IPA selection species” (threatened species and locally endemic or restricted range). Recent taxonomic revisions estimate the number of national endemics for the north of Algeria (excluding the Sahara) to be over 300 taxa. In the present study, data were extracted from the global list of 22 IPAs identified for the north of Algeria. The species considered are i) threatened species as defined by the 1997 IUCN global red list of plants, ii) locally endemic species, iii) nationally threatened species. Trigger species, identified by combining the criteria of endemism and rarity, are mainly Algerian national endemics but also include some AlgerianMoroccan and Algerian-Tunisian endemics. One hundred and fifty two (152) trigger species were identified and these species, which have high ecological value, can be used to characterize the particular floristic interest of a site and can therefore be a useful tool for conservation purposes. Important gaps in knowledge have been highlighted, in particular those relating to taxonomy and the lack of up-to-date field data. It is therefore essential to undertake in situ research in order to better understand the distribution and status of these species. A flexible approach to identifying and recognising priority sites for plants using surrogate criteria, supplemented by expert opinion, alongside existing globally standardised criteria, is therefore essential if the most important sites for plant diversity are to receive the conservation attention they deserve.


IntroductIon
In 2010 a study was undertaken to identify important plant areas (IPA --key biodiversity areas for plants) in the south and east Mediterranean region, in order to prioritise the best sites for plant conservation action (Radford et al. 2011).This paper explains in detail how identification of these sites was undertaken in Algeria.It is a country with typical south and east Mediterranean biodiversity, with a huge number of local endemics.Knowledge on these species is partially documented and there is little data on the threat status of plant species.This study follows the work of identification of important plant areas (IPAs) initiated for Algeria by Yahi et al. (2011).It relates exclusively to the flora of northern Algeria (Mediterranean part), a region of 475,000km 2 .
The Mediterranean basin has long been recognised as a global Biodiversity Hotspot (Médail & Quézel 1997) due to the size and diversity of its flora; 10% of the world's vascular plants occur on 1.6% of the land surface.Ten smaller hotspots of floristic biodiversity within the basin have also been identified (Médail & Quézel 1997;Véla & Benhouhou 2007), two of which overlap with Algerian territory: the Betico-Rifian complex in Algeria, Morocco and Spain and the Kabylies-Numidia-Kroumiria complex in Algeria and Tunisia.The latter has recently been identified as a centre of endemism and refuge area for species at the geographical limit of their distribution (Véla & Benhouhou 2007;Médail & Diadéma 2009).These regions are of immense importance for conservation but are too large scale for focused site-based conservation actions.
The north of Algeria (excluding the Sahara) holds 224 known nationally endemic taxa and approximately 1,630 rare taxa (Quézel & Santa 1962-1963;Véla & Benhouhou 2007).However, following recent taxonomic revisions the estimate of the number of national endemics is now placed at over 300 taxa and the total number of taxa of elementary rank (species or subspecies) is 4,000 (Dobignard & Chatelain 2010-2011), up from the previous count of 3,700 (Quézel & Santa 1962-1963).This high biogeographical endemism is shared with bordering countries; thus Morocco to the west has 124 Algerian-Moroccan endemic taxa and Tunisia in the east has 58 Algerian-Tunisian endemic taxa (Véla & Benhouhou 2007).
This local endemism, associated with high habitat diversity, is a result of the Mediterranean climate, in turn influenced by altitude, large thermal amplitudes and a west-east rainfall gradient, combined with considerable topographic, geomorphological and geological diversity (Seltzer 1946;Emberger 1955).
The IPA (Anderson 2002;Plantlife International 2004) attempted to identify site-scale priority areas for conservation, using standard criteria that in part, corresponded to those used for identifying key biodiversity areas (Langhammer et al. 2007).

Methods
Important plant areas in northern Algeria were identified using a combination of IPA criteria (Anderson 2002;Plantlife International 2004) and Important Forest Area criteria (Regato 2001), which were modified to reflect the data available for plant species in North African countries (Yahi et al. 2011; IUCN, Plantlife, WWF 2010 unpublished workshop report).IPAs in northern Algeria were delineated for those sites harbouring a number of "IPA selection species" (threatened species and locally endemic or restricted range).In terms of IPA criteria (Plantlife International 2004), these IPA selection species allowed application of criterion A (presence of globally, regionally and/or nationally endemic threatened species) and partial application of criterion B (species richness), by selecting the richest sites for locally endemic (restricted range) species.Sites selected using richness were not selected by habitat type (as required by full application of criterion B), as such data is not available in Algeria.There are no threatened habitat classifications for northern Algeria so IPA criterion C, for such habitats, could not be applied effectively.It is beyond the scope of the current project to delineate IPAs everywhere that restricted-range species occur in Algeria because there are so many such species in northern Algeria alone.
These criteria broadly relate to the KBA criteria for vulnerability and irreplaceability, although for one of the latter subcriteria, the threshold of 50,000km² used to define restricted range for animal taxa (Langhammer et al. 2007) is too large to apply to plant species, particularly in hotspot regions, because it would result in much of the northern part of the country being delineated as KBAs.
In the present study, data were extracted from the global list of the 21 IPAs identified for the north of Algeria (Yahi et al. 2011) and a new site added (the Collo Peninsula) using data collated subsequently.The taxa listed for each site are derived from literature sources (Battandier 1888-1890, Battandier & Trabut 1895, Quézel & Santa 1962-1963) and/or from personal data obtained during field observation.Taxonomic sources are the flora of Quézel & Santa (1962-1963) and the synonymic index of Dobignard & Chatelain (2010-2011).The species considered are: (i) threatened species, as defined by the 1997 IUCN global red list of plants (Walter & Gillett 1998) and the 2010 IUCN Mediterranean Red List of Freshwater Plants (Garcia et al. 2010); we do not include species listed "Rare", "Near Threatened", or "Data Deficient"; (ii) locally endemic (restricted-range) species, defined as those with distributions of greater than 100km 2 but less than or equal to 5,000km², called restricted range endemic species, and those with a distribution less than or equal to 100km², called siterestricted endemic species -these two categories are mutually exclusive (IUCN et al. 2010); (iii) nationally threatened species defined as rare, according to the criteria of rarity given in the Algerian flora (Quézel & Santa 1962-1963).
In this study, we combine the criteria of endemism and rarity to identify what we call "trigger species".Trigger species for Key Biodiversity Areas are all those species that 'trigger' either the vulnerability and or the irreplaceablility criteria and thus 'trigger' sites as a KBA (Langhammer 2007).These were selected from the global IPA lists and are mainly Algerian national endemics but also include some Algerian-Moroccan and Algerian-Tunisian endemics, for those present in IPAs near the respective national borders.Their high ecological value can be used to characterize the particular floristic interest of a site and can therefore be a useful tool for conservation purposes.

results
Twenty two IPAs are identified in northern Algeria.These were identified within the phytogeographical sectors of the Oran region, the Algiers region, the Kabylies and Numidia, the Constantine mounts, the High Plains and the Saharan Atlas (Quézel & Santa 1962-1963).The sites selected represent a range of habitats from the coasts to the mountains, encompassing wetlands, hills and plains.They extend from the wetland complex in El Kala in eastern Algeria to the montane forest of Ghar-Rouban in the westernmost area of the country (Image 1).They cover a total of 10,656km 2 , comprising approximately 2.5% of Algeria's Mediterranean region.Of the 22 sites, 7 (31%) are already benefitting from protectedarea status as national parks.A number of additional sites have been proposed as IPAs but further field investigations in these areas must be undertaken before these can be confirmed.These sites include Djebels Ksours and Krouz, Djebel Aïssa (recently classified as national park) and Djebel Amour, located in the Saharan Atlas.
Using the species lists established for the 22 IPAs, it is possible to make a first analysis linking these IPAs with KBA criteria (Table 1).
The 587 species correspond to the total number of nationally threatened species extracted from the 22 IPAs list.It includes 153 trigger species and 434 nationally rare species.Among this total, there are two Critically Endangered, 11 Endangered and 10 Vulnerable species, a total of 23 species from the IUCN 1997 and 2010 red lists (Appendix 3).With regards to the irreplaceability criterion, 74 restricted-range species and 78 site-restricted species were identified (Appendices 1 and 2), including, respectively, 70 and 62 species not currently listed as threatened.Twenty of the species that qualify under the vulnerability criterion therefore, also qualify under the irreplaceability criterion; 16 are site-restricted and four are restricted range.For further details see Appendix 3.
In Table 2, for each of the 22 IPAs, we list the numbers of nationally rare species (Quézel & Santa 1962-1963), of species listed as threatened (Critically Endangered, Endangered and Vulnerable) on IUCN Red Lists (Walter & Gillett 1998;Garcia et al. 2010), and of restricted-range endemic and site-restricted endemic species.We also note whether each IPA has also been identified as a key biodiversity area for the presence of animal trigger species, in addition to plants (CEPF 2010).
In Algeria the large number of species associated with the irreplaceably (restricted range) makes the possibility of an extremely long list of trigger species (and corresponding long list of sites).Conversely, the lack of IUCN threat status information, mean species hitting the vulnerability criteria are probably underrepresented.Overcoming this data deficiency, a list These selected trigger species are mainly "SRE" species with a few "RRE" species.The complete list being given in Appendix 4. The total of 86 selected trigger species includes 13 common to two or more IPAs.Twenty IPAs contain trigger species that only exist at one site.Many of these species are considered highly threatened and may be Alliance of Zero Extinction sites (sites containing the only remaining population of Critically Endangered species as defined using IUCN criteria) (Ricketts et al. 2005).However, lack of precise data for IUCN species assessments prevents us being able to confirm this.

dIscussIon
Over 50% of the (total) IPAs identified for northern Algeria are located within the two regions in the Maghreb described as plant diversity hotpots by Véla & Benhouhou (2007): 11 are in the Kabylies-Numidia-Kroumiria hotspot and three in the Betico-Rifean hotspot.However, eight IPAs have been identified outside of those areas.Of the 22 IPAs in northern Algeria, 17 IPAs are found within the priority corridor "Mountains, Plateaus, and Wetlands of the Algerian Tell and Tunisia" while the remaining five fall within the "Oranie and Moulouya" corridor (CEPF 2010).Fifteen Algerian IPAs (68%) overlap with Key Biodiversity Areas identified using animal taxa, of which there are a total of thirty eight in the region -this overlap is greater than what was identified for other south and east Mediterranean countries within the CEPF analysis (Radford et al. 2011).
The identification of priority sites for plant conservation in Algeria, which has brought together significant amounts of existing data in a site-based format, will serve to increase the profile of northern Algeria's priority sites for plants, and to target investment in their conservation.However, the desire to ensure these sites meet global selection criteria does present a number of challenges, which indeed are common to all countries in the south and east Mediterranean.These challenges begin with the sheer number of plant species that are important to conservation and extend to the often difficult and incomplete taxonomies, a chronic lack of current data on species (and habitat) distributions and the extremely limited number of formal species status assessments (and associated Red Lists).
Only 79 taxa from the approximately 4,000 present in Algeria have been assessed using the latest IUCN criteria-under 2% of the flora.Twenty three of these species are classified as threatened (and therefore available for use under the KBA vulnerability criterion).This total is undoubtedly a fraction of the true number for a country which hosts 407 endemic or nearendemic species (Véla & Benhouhou 2007), of which at least 78 have distributions of less than 100km² and a further 74 have distributions of less than 5,000km².Species assessed as threatened on the IUCN Red List are mainly endemic.Some non-endemic taxa, such as Senecio linifolius, which we suspect to be Endangered and is found at only one site in Algeria (Oran Hills), does not have any kind of formal conservation status.It is thus essential to undertake in situ research in order to understand the distributions of both endemic and non-endemic plant species and their conservation status.It is important also to recognise that the 1997 Red List data are old and incomplete.A more recent Red List is available but only for freshwater plants (Garcia et al. 2010).
In Algeria, the flora of Quézel & Santa (1962-63), is the only valid national taxonomic reference, and is insufficient to (i) solve the many questions related to taxonomy, and (ii) give precise distributions of the species.It should be noted that the distributions of some restricted-range species were taken from those described by Quézel & Santa 1962-63, and may be out of date now due to potential changes in the range of species therein and data collected subsequently.It should also be noted that several species not mentioned by these authors had already been described by Maire (1952Maire ( -1987) ) adding to the potential complexity of the national taxonomic picture for plants.Recent field investigations by the authors of this paper (De Belair & Boussouak 2002;De Belair et al. 2005;De Belair &Véla 2011;Véla et al. 2012, andunpubl. pers. obs. andcollaborators (Ouarmim &Dubset 2008;Medjahdi et al. 2009) resulted in several new or rediscovered species records for Algeria: Brassica "numidica" (Edough peninsula), Erysimum sp.nov.(Gouraya), Nymphoides peltata (Guerbès), Sixalix farinosa (El Kala 1), Seseli praecox (Edough peninsula), Serapias stenopetala (El Kala 1) and Teucrium maghrebinum (Traras mountains, Oran Hills).It is also important to confirm the real distribution of poorly known species such as Erodium battandieranum (Taza), Isoetes perralderiana, Silene chouletii (Akfadou) and Linaria burceziana (Ghar Rouban).
The identification of trigger species was facilitated by the IPA methodology which has been validated for many Mediterranean countries (IUCN et al. 2010).The majority of these are found at high altitude, on the summits of the northern Algerian mountains.Here, the rate of speciation is high due to the isolation of populations, resulting in a large number of endemic species (Table 3).
Trigger species were also identified for sites characterised by their geological and geomorphological distinctiveness, such as the limestone and dolomitic cliffs in the Gouraya IPA and the close proximity of dunes, rocks and small islands in the Oran Hills IPA.Detailed analyses of these lists highlight several species at the edges of their distributions in northern Africa and which may be threatened on a regional or national level, due a combination of small populations, local pressures (deforestation, habitat fragmentation, drought etc), but not across their whole range.This is the case for Buxus sempervirens, Galium odoratum, Neotia nidus-avis, Populus tremula, Stellaria holostea, Viburnum lantana (Babor), Corydalis solida, Hieracium juranum, Monotropa hypopitys, Ononis aragonensis (Babor, Djurdjura), Juniperus sabina (Djurdjura), Paeonia atlantica (cf.Morocco and Algeria), Laurenbergia tetrandra, Oldenlandia capensis, Polygonum amphibium (El Kala 1), Brassica insularis (Edough peninsula), Sedum stellatum (Collo peninsula).These 'edge of range' populations are potentially important sources of genetic variability, which may, particularly in the case of forest species, provide potential for adaptation to the threat of climate change (Regato 2008 and references therein).
The present work has resulted in the identification of potentially threatened species whose conservation status requires formal assessment.Such species reinforce arguments in favour of protection and the urgent conservation of the IPAs in which they occur.Important gaps in knowledge have been highlighted, in particular those relating to taxonomy and the lack of up-to-date field data.It is therefore essential to undertake in situ research in order to better understand the distribution and status of these species.Without this effort, it will be impossible to apply criteria that are compatible with those of KBAs and be confident that the results are comprehensive.Up-to-date data will require considerable time and resources; neither are available in abundance.
A flexible approach to identifying and recognising priority sites for plants using surrogate criteria, supplemented by expert opinion, alongside existing globally standardised criteria, is therefore essential if the most important sites for plant diversity are to receive the conservation attention they deserve.Using 'globally standardised criteria' that can only be applied effectively to taxa from better documented taxonomic groups will introduce taxonomic bias to the lists of KBAs, which is better avoided.This applies both in Algeria and other countries and regions which possess exceptionally diverse floras with considerable local endemism.This is particularly important in floristic hotspots such as the Mediterranean, where plant El Kala 2, Edough peninsula

Image 1 .
Localisation of the 22 IPAs identified for the North of Algeria.

Table 2 . Nationally rare species, IUCN Red List species, restricted-range species and restricted site species per IPA, and presence of animal as well as plant trigger species. IPAs Nationally rare species IUCN Red List 1997 & 2010 (CR/EN/VU only)
of 'selected' trigger species that highlight the most threatened and restricted species are chosen to designate as Important Plant Areas -or Key Biodiversity Areas for Plants.Selected trigger species present in only one IPA are shown in bold.

Restricted range endemic species from the 22 IPAs of North Algeria (range limited to less than 5000 km²)
(Desf.) Kuntze subsp.spathulatum Q. & S. * Some taxa are treated here as full species even though they are not yet formally recognized as such, reflecting the relative lack of taxonomic work on the flora of the Maghreb.Steinh.[= O. provincialis Balbis var.laeta (Steinheil) Maire & Weiller, O. pauciflora Ten.subsp.Laeta (Steinh.)Kreutz]