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Subnival habitats of the Central Caucasus represent typical rocky environments with very sparse soil cover and patchy vegetation. We studied how spatial distribution of plant species in a subnival habitat (alpine-nival ecotone) depends on the size of rock particles. We described the distribution patterns of plants and rock particles of various sizes, and examined the possible links between these patterns using correlation analysis and multivariate tests. We found that the largest size class (20-60 cm) was in a strong negative correlation with smaller classes (0.2-0.6 cm, 0.6-2 cm and 2-6 cm), but correlation was insignificant among the largest fragments (6-20 cm) and the soil patches. The CCA included 31 species (frequency >10) and the goodness-of-fit of the obtained ordination was assessed by permutation test. The CCA ordination revealed several species with a clear preference for soils (Carex tristis and Sibbaldia parviflora), while other species preferred mid-sized (20-60 cm) rock particles (Tephroseris karjaginii, Ziziphora puschkinii, Festuca supina, Minuartia inamoena and Saxifraga juniperifolia). Further, Senecio sosnowskyi and Ziziphora subnivalis tended to colonize large (6-20 cm) rock fragments. Overall, our results show a clear differential preference of species for certain sizes of rock particles that conforms well to the patchy pattern of vegetation typical for subnival habitats: many species that prefer a fine grained substratum might clump together at such fine-grained spots and form the patches of associated plants provided there are facilitative interactions among them; the species that prefer coarser-grained substrata might establish as solitary plants outside of the patches.

BACKGROUND: Cyrtanthus nutans R.A.Dyer is a range-restricted species occurring in northwestern KwaZulu-Natal, South Africa and in Eswatini, and is currently classified as Vulnerable in accordance with the IUCN criteria. Land transformation and disturbance of natural habitats have resulted in an ever-increasing fragmentation of the species' range. OBJECTIVES: This manuscript provides a description of some of the abiotic and biotic factors associated with the remaining natural populations of C. nutans in the Sour Sandveld and Moist Tall Grassland Bioresource Groups of northwestern KwaZulu-Natal METHODS: An investigation was conducted in the northwestern KwaZulu-Natal region to determine the effect that key ecological and anthropological determinants have in influencing the distribution and survival of the species. Data collected included sites of occurrence, estimated population numbers, elevation, ecological factors (soils/geology, climate, veld composition), and human/animal activities. RESULTS: The northwestern KwaZulu-Natal C. nutans populations were found to occur primarily in untransformed veld within the Moist Tall Grassveld, Dry Highland Sourveld and Sour Sandveld Bioresource Groups. It occurs largely on gradients of < 10% on mid- to lower terrain slopes and predominantly within an altitude range of between 1 100 and 1 300 m a.m.s.l. CONCLUSION: C. nutans occurs in a narrow altitudinal range and has a preference for soils with high nitrogen and organic carbon and low phosphorus and acidity levels.

Climate and land‐use change jointly affect the future of biodiversity. Yet, biodiversity scenarios have so far concentrated on climatic effects because forecasts of land use are rarely available at appropriate spatial and thematic scales. Agent‐based models (ABMs) represent a potentially powerful but little explored tool for establishing thematically and spatially fine‐grained land‐use scenarios. Here, we use an ABM parameterized for 1,329 agents, mostly farmers, in a Central European model region, and simulate the changes to land‐use patterns resulting from their response to three scenarios of changing socio‐economic conditions and three scenarios of climate change until the mid of the century. Subsequently, we use species distribution models to, first, analyse relationships between the realized niches of 832 plant species and climatic gradients or land‐use types, respectively, and, second, to project consequent changes in potential regional ranges of these species as triggered by changes in both the altered land‐use patterns and the changing climate. We find that both drivers determine the realized niches of the studied plants, with land use having a stronger effect than any single climatic variable in the model. Nevertheless, the plants' future distributions appear much more responsive to climate than to land‐use changes because alternative future socio‐economic backgrounds have only modest impact on land‐use decisions in the model region. However, relative effects of climate and land‐use changes on biodiversity may differ drastically in other regions, especially where landscapes are still dominated by natural or semi‐natural habitat. We conclude that agent‐based modelling of land use is able to provide scenarios at scales relevant to individual species distribution and suggest that coupling ABMs with models of species' range change should be intensified to provide more realistic biodiversity forecasts., Land‐use and climate change will have important effects on the future of biodiversity. We predict changes to the potential distribution of vascular plants in response to these two drivers in a region of the Austrian Alps. We therefore combine agent‐based modelling of land owners' decisions with species distribution modelling. We find that both drivers determine the realized niches of the studied plants, with land use having a stronger effect than any single climatic variable in the model. Nevertheless, the plants' future distributions appear more responsive to climate than to land‐use changes.

Significance Human activities can drive both species’ range contractions and expansions. Species’ responses to human activities are suggested to be influenced by their geographic range sizes. Here, we test the idea that human impacts cause range declines in small-range species but promote range expansion of common species, using distribution data for 9,701 plants across China to examine the relation of human activities to the degree to which species fill their climatic potential ranges. We found that narrow-ranged and widespread species indeed exhibited opposing responses to human activities, with their range filling decreasing and increasing with human influence, respectively. These findings suggest that human activities have reduced ranges of narrow-ranged species but expanded those of widespread species, causing biotic homogenization across China., Human activities have shaped large-scale distributions of many species, driving both range contractions and expansions. Species differ naturally in range size, with small-range species concentrated in particular geographic areas and potentially deviating ecologically from widespread species. Hence, species’ responses to human activities may be influenced by their geographic range sizes, but if and how this happens are poorly understood. Here, we use a comprehensive distribution database and species distribution modeling to examine if and how human activities have affected the extent to which 9,701 vascular plants fill their climatic potential ranges in China. We find that narrow-ranged species have lower range filling and widespread species have higher range filling in the human-dominated southeastern part of China, compared with their counterparts distributed in the less human-influenced northwestern part. Variations in range filling across species and space are strongly associated with indicators of human activities (human population density, human footprint, and proportion of cropland) even after controlling for alternative drivers. Importantly, narrow-ranged and widespread species show negative and positive range-filling relationships to these human indicators, respectively. Our results illustrate that floras risk biotic homogenization as a consequence of anthropogenic activities, with narrow-ranged species becoming replaced by widespread species. Because narrow-ranged species are more numerous than widespread species in nature, negative impacts of human activities will be prevalent. Our findings highlight the importance of establishing more protected areas and zones of reduced human activities to safeguard the rich flora of China.

Northern Zagros forests are one of the most important ecosystems in Iran from ecological and socio-economic points of view. This study was done to determine the most important gradients affecting on plant species distribution by using ordination methods. Environmental variables including inclination, slope aspect, elevation, litter depth, bare soil percentage, soil organic carbon, available P, K, N, soil texture, pH and EC were measured in 60 plots along with vegetation data and canopy cover. Redundancy detrended analysis (RDA) was performed to identify the main environmental gradients. 90 plant species belonging to 75 genus and 32 families were determined. Species belonging to Asteraceae, Apiaceae, Poaceae, and Fabacea families had the most contribution in floristic composition. RDA results showed that with considering spatial autocorrelation of sample plots as covariate, slope aspect, litter depth, canopy cover, C/N, elevation and outcrop explained 30% of the total variations in floristic composition. The results of this study can be used to do more efficient management of these fragile ecosystems.

South Africa is a megadiverse country, and its biodiversity is endangered by population pressure and the development needs of a developing country. In order to address the rapid decline in biological diversity, biodiversity planning has become a key focus area that aims at identifying priority areas for species and ecosystem conservation within and outside of formally protected areas. Plant conservation hotspots are identified by the quantification of indicator taxa such as plant taxa richness, rarity and endemism. But the urgent and enormous task of biodiversity assessment for conservation planning requires that we make most of what we know. Therefore, this study seeks to make a contribution by finding new ways of biodiversity pattern estimation from the extrapolation of incomplete sets of plant species distribution data at the Quarter Degree Grid level. Incomplete sampling across the grids of a study area results in false records of species absence and thus a biased biodiversity estimation. As a possible solution, plant distribution data for the western Central Bushveld Bioregion has been standardized using two profiles, namely the ‘Centroid Grid’ and ‘Integrated Grid’ profile. The former involves the strengthening of under-sampled grids by extrapolating species occurrences from three adjacent grids with the most similar vegetation units, whereas the latter integrates phyto-diversity data for the four grids intersecting at each grid reference point. Standardized data has proved to provide a means to counter the bias in plant diversity data linked to Quarter Degree Grids by a) strengthening of under-sampled grids and b) visibly smoothing out the gaps between under- and well-sampled grids, which resulted in improved biodiversity estimation for more representative spatial biodiversity modelling. Interpolation created geo-referenced polygons for more explicit use in the identification of areas of conservation concern at bioregional scale. However, well-sampled grids still dominate the outcomes of the analysis by creating spatial sampling bias. Therefore, this approach to calibrate Quarter Degree Grid resolution of spatial data is an additional attempt to achieve more representative mapping of biodiversity patterns, which is a prerequisite for strategic conservation planning for ‘living landscapes’. Thesis (MSc (Environmental Sciences))--North-West University, Potchefstroom Campus, 2012

Doğal bitki örtüsü tür dağılımının uydu görüntüleri yakın kızılötesi bandını temel alarak belirlenmesi olanaklarını araştıran bu çalışma için tür çeşitliliği bakımından zengin Karaburun Yarımadası araştırma alanı olarak seçilmiştir. Yarımada sınırları içinden seçilen örnek alanlarda yapılan arazi gözlem çalışmalarında 111 alana ait bitki türü kompozisyonu, bitkilerin toprağı örtme oranı kaydedilmiş ve bu veriler bilgisayar ortamına aktarılarak ASTER uydusu görüntülerinden oluşturulan NDVI (normalize edilmiş fark bitki örtüsü indeksi) görüntüsü ile ilişkilendirilmiştir.Gözlem alanları baskın tür birlikteliklerine göre 13 sınıfa ayrılmıştır. Sınıfların ortalama NDVI değerine yakınlık kriteri vasıtasıyla gerçekleştirilen tür tahmini yöntemi 40 kontrol alanında test edilmiştir. Sonuç olarak, bitki indeksinin tek başına tür tahmininde kullanılmasının hatalı sonuçlar doğuracağı kanaatine varılmıştır. Yaprak yoğunluğu ile bitki indeksi arasında pozitif korelasyon gözlenmiştir.Gözlem alanları mensup oldukları bitki örtüsüne göre üç sınıfa (frigana, maki, orman) ayrılmış ve aynı yöntem bitki örtüsü tahmini için de uygulanmıştır. Yöntemin bitki örtüsü tahmini için de yetersiz olduğu sonucuna ulaşılmıştır.Yöntemin geliştirilmesi durumunda doğal bitki örtüsü tür dağılımına ilişkin bilginin görece az insan emeği ile elde edilebileceği düşünülmektedir. Karaburun Peninsula with its broad species diversity is chosen as the research area for this research project which aims to determine species distribution in natural vegetation by use of satellite images. Species composition and cover ratio data of 111 fields are recorded during survey work. These data are associated with normalized difference vegetation index (NDVI) data derived from ASTER satellite images.Fields are separated into 13 classes according to dominant species composition. Species prediction method which is performed according to the criteria of distance between field NDVI value and class average NDVI value is tested in 40 ground control points. As a result, it has been concluded that usage of NDVI alone to predict species composition produces inaccurate results. Strong positive correlation has been observed between cover ratio and NDVI values.Fields are separated again into 3 land cover classes. The same method is applied in order to predict land cover type. The method has again been found inadequate.It has been thought that information about species distribution could be achieved with lesser field work if improvement in the method can be obtained. 78