چكيده لاتين :
Since "Biodiversity" implies a broad area of meanings and there is a lack of clear definition which involves all these implications; its assessment seems to be problematic on the ground.
surrogates have been applied broadly in practice. However, regarding recent evolutions in conservation approaches from species toward ecosystem and landscape. Today biodiversity involves processes, functions and phenomena, which are not tractable in species conservation approaches.
Vegetation types have several habitat implications and therefore have been used in many studies as biodiversity surrogate. So, in this study we used the vegetation types and endemic/rare plants species as biodiversity surrogates in order to assess the representativeness of existing PAs system in Central Zagros Mountain one of the richest biodiversity regions in Iran versus established conservation targets. The methodology used in this paper could be applied in other parts of Iran, since it is for the first time in the country according to our literature review.
The study area, Charmahal & Bakhtiari province, covers 16432 square km (ca. 1% of the country) and located in 31° 9ʹ to 32° 48ʹ N latitude and 49° 28ʹ to 51° 25ʹ E longitude along with NW-SE. Approximately 80% of the study area is mountainous with average 2153 m above see level. Mean annual temperature vary between 8.5 and 20 °C and precipitation between 254-1500 mm. Socio politically, 857910 people inhabit in study area according to last census, from which 51.55% live in urban areas, 48.33% in rural areas and 0.11%, are nomads. According to Forests & Rangelands Organization (2004) approximately 55.2% of the study area is covered by rangelands, 20.5% by forest, 16% by cultivated lands and the rest is residential areas, water bodies, bare lands and rocks outcrops.
This area is part of Irano-Turanian floristic region and contains 923 plant species, 294 animal species (170 birds, 62 mammal, 35 reptile, 22 fish and 5 amphibians). Biodiversity conservation system (terrestrial) consists of 2 components including: (i) Statutory protected areas; national park, protected areas and national natural monument, (ii) Planned areas; forbidden hunting areas (see Table 1 and Figure 1). this study has been conducted in 4 stages, according to "systematic conservation planning" procedure (Margules and Pressey 2000): 1) selecting surrogates, 2) compiling data and information on surrogates, 3) setting goal and targets for surrogates, 4) reviewing existing protected areas in terms of surrogates versus established targets.
Only 17 out of 36 vegetation types exist in existing protected and/or planned areas. However, for 12 out of 15 vegetation types exist just in statutory PAs, established targets are not met sufficiently and for 3 of them targets are satisfied more than established level even up to 55% (e.g. in the case of Scariola orientalis -Astragalus spp.). Taking into account planned areas, 10 out of 17 vegetation types are protected less than established targets and 7 are protected more than established targets even up to 73.65% (e. g. in the case of Astragalus susianus - Cousinia cylindracea). In the case of endemic/rare plants species, 27 out of 52 species are represented at least once in statutory and/or planned PAs. 16 out of these 27 endemic/rare species are represented just in statutory PAs, 6 just in planned areas and 5 in both.
Sabz-Kooh with 11 out of 36 vegetation types is the most representative PA followed by Sheida (planned area) with 9, Helen with 8 and Tang-e Sayyad with 6 types (Table 3). Two types (Astragalus adsendense -Agropyrum intermedium and Astragalus spp. - Cousinia spp.) are common amongst 3 PAs. Sabz-Kooh and Helen have 4 common vegetation types, Sabz-Kooh and Tang-e Sayyad have 2 and Helen and Tang-e Sayyad have no common vegetation types. Two types (Gundelia tournefortii - Cousinia spp. and Perennial grasses) are represented just in planned areas, 7 types represented only in statutory PAs and the rest (8 types) are represented both in statutory and planned areas (Table 3). Therefore, the level of representing vegetation types will differ with or without taking into account planned protected areas. For example conservation goal for Annual grasses - Annual forks will differ from -16.2% (under representation) to +2.47% (over representation) taking into account planned areas. In Table 3 these differences have been calculated for other vegetation types.
The total area needed to satisfy conservation targets for all vegetation types, according to Table 2, is 265543.33 ha which equals to 16.17% of the study area. This is approximately two times of existing statutory PAs (7.43%) and a little more than total area currently is under protection in both statutory and planned PAs (14.76%).
In terms of plants species, Gheisari with 487 out of 923 species exist in the study area seems to be the richest and most diverse area, followed by Sabz-Kooh with 433, Sheida with 401, and Tang-e Sayyad with 250 species. However, in terms of representing endemic/rare plant species, Sabz-Kooh contains 11 species, followed by Gheisari with 7, Sheida with 5, Tang-e Sayyad 3 and Helen with 1 species. Most concentration of endemic/rare plants species exist in Kallar Mount adjacent to Sabz-Kooh protected area and Bazoft valley in north-east of the study area.
No study has been done in the same subject or scale of our work in the study area, to the best of our acknowledge, in order to discuss and compare results, however Makhdoum (2008) in a similar study in the scale of country pointed out the conservation gaps in Irano-Turanian floristic region especially Zagros Mountains floristic province which is an endemism center of the country. Our findings approve these gaps in a finer scale.
There are some differences between our results and studies which have been conducted in finer scales (1:50,000) such as Barresi-e Manab-e Ab (2002) and Varz-Boom (2002) in terms of the number and kinds of vegetation types across the study area and within the PAs. These differences could be a result of scale movement in which conglomeration of smaller types is inevitable. It also could be due to the dynamic nature of vegetation types in which plants species composition change during time. Consequently, one season that sampling is unable to record all this variability is because these studies were done at different times and as a consequence the scales show different results.
There are also important differences among vegetation types in terms of satisfied conservation targets, especially between rangeland and forest types. This could be due to this fact that most parts of the study area covered by rangelands (55%) and therefore PAs have biases toward rangeland types. For example Astragalus susianus - Cousinia cylindracea and Scariola orientalis - Astragalus spp. with +73.65 and +55.33 have the most over-representation respectively (see Table 3). It also because forest types like Amygdalus orientalis and Quercus brantii are distributed in a much broader range than the study area, so they might be protected in a satisfied level in other areas.
Although the planned (forbidden hunting) areas are established originally for protecting animals species, but they have an important role in filling some conservation gaps of vegetation types and endemic/rare plants species. But, even with adding all planned areas to statutory PAs, still important gaps remain in vegetation types conservation, as 19 out of 36 vegetation types and 24 out of 52 endemic/rare plants species are not represented in statutory or planned PAs originally.
In a comprehensive conservation gap analysis it is important to consider entire Zagros floristic province, especially for vegetation types which extended throughout the region.
The number of common vegetation types between Sabz-Kooh and Helen PAs (4 types) which are in closest distance and most similar in environment, Sabz-Kooh and Tang-e Sayyad (2 types) which are more distant and Helen and Tang-e Sayyad (0 type) which are most distant; approve the possibility of using "Environmental Distance" as biodiversity surrogate as Faith and Walker (1996) pointed out. Relatively good plant species richness of Sabz-Kooh PA as well as Gheisari and Sheida planned areas could be the result of conservation which is provided better condition for plants regeneration compared to other areas. In other words these areas have not been richer than neighboring areas originally (Oldfield et al., 2004). Meanwhile, the number of plants species counted in an area (richness), which highly depends on sampling intensity, does not provide a good measure for biodiversity representativeness. However existing PAs have explicit biases toward high altitudes which provide appropriate conditions for alpine and sub alpine endemic/rare plants species. Nourozi et al., (2008) have shown this and our findings indicate similar evidences. So, there are conservation gaps for endemic/rare plants species scattered in lower altitudes. In order to fill these gaps it needs to review existing PAs boundaries to encompass lower altitudes or consider a complementary fine scale approach for adding new PAs to current network.
