Conservation biology aims at identifying areas of rich biodiversity. Currently recognized global biodiversity hotspots are spatially too coarse for conservation management and identification of hotspots at a finer scale is needed. This might be achieved by identification of areas of endemism. Here, we identify areas of endemism in Iran, a major component of the Irano-Anatolian biodiversity hotspot, and address their ecological correlates. Using the extremely diverse sunflower family (Asteraceae) as our model system, five consensus areas of endemism were identified using the approach of endemicity analysis. Both endemic richness and degree of endemicity were positively related to topographic complexity and elevational range. The proportion of endemic taxa at a certain elevation (percent endemism) was not congruent with the proportion of total surface area at this elevation, but was higher in mountain ranges. While the distribution of endemic richness (i.e., number of endemic taxa) along an elevational gradient was hump-shaped peaking at mid-elevations, the percentage of endemism gradually increased with elevation. Patterns of endemic richness as well as areas of endemism identify mountain ranges as main centres of endemism, which is likely due to high environmental heterogeneity and strong geographic isolation among and within mountain ranges. The herein identified areas can form the basis for defining areas with conservation priority in this global biodiversity hotspot.

Endemism is one of the most important concepts in biogeography and is of high relevance for conservation biology. Nevertheless, our understanding of patterns of endemism is still limited in many regions of high biodiversity. This is also the case for Iran, which is rich in biodiversity and endemism, but there is no up-to-date account of diversity and distribution of its endemic species. In this study, a comprehensive list of all endemic vascular plant species of Iran, their taxonomic composition and their geographical distribution are presented. To this end, a total of 2,597 (sub)endemic vascular plant species of Iran were documented and their distribution in three phytogeographical regions, two biodiversity hotspots and five areas of endemism were analysed. The Irano-Turanian phytogeographical region harbours 88% of the Iranian endemics, the majority of which are restricted to the Irano-Anatolian biodiversity hotspot (84%). Nearly three quarters of the endemic species are restricted to mountain ranges. The rate of endemism increases along an elevational gradient, causing the alpine zone to harbour a disproportionally high number of endemics. With increasing pastoralism, urbanization, road construction and ongoing climate change, the risk of biodiversity loss in the Iranian mountains is very high, and these habitats need to be more effectively protected.

Aims Understanding fine‐grain diversity patterns across large spatial extents is fundamental for macroecological research and biodiversity conservation. Using the GrassPlot database, we provide benchmarks of fine‐grain richness values of Palaearctic open habitats for vascular plants, bryophytes, lichens and complete vegetation (i.e., the sum of the former three groups). Location Palaearctic biogeographic realm. Methods We used 126,524 plots of eight standard grain sizes from the GrassPlot database: 0.0001, 0.001, 0.01, 0.1, 1, 10, 100 and 1,000 m2 and calculated the mean richness and standard deviations, as well as maximum, minimum, median, and first and third quartiles for each combination of grain size, taxonomic group, biome, region, vegetation type and phytosociological class. Results Patterns of plant diversity in vegetation types and biomes differ across grain sizes and taxonomic groups. Overall, secondary (mostly semi‐natural) grasslands and natural grasslands are the richest vegetation type. The open‐access file ”GrassPlot Diversity Benchmarks” and the web tool “GrassPlot Diversity Explorer” are now available online (https://edgg.org/databases/GrasslandDiversityExplorer) and provide more insights into species richness patterns in the Palaearctic open habitats. Conclusions The GrassPlot Diversity Benchmarks provide high‐quality data on species richness in open habitat types across the Palaearctic. These benchmark data can be used in vegetation ecology, macroecology, biodiversity conservation and data quality checking. While the amount of data in the underlying GrassPlot database and their spatial coverage are smaller than in other extensive vegetation‐plot databases, species recordings in GrassPlot are on average more complete, making it a valuable complementary data source in macroecology.

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Complex interaction of rheologically contrasting layers within the lithosphere during the collision of continental plates leads to active faulting, which represents a serious hazard to the population and infrastructure. One of the collision scenarios presumes the existence of a middle-lower crustal channel composed of subducted silicic upper crustal rocks, which is thought to exist in the Tibetan-Himalayan system. Based on the results of seismic tomography, we argue that a similar mechanism of crustal channeling takes place beneath the Zagros mountain system in southwestern Iran. The 3D seismic velocity model reveals an inverted crustal architecture of the collision zone, in which the low-velocity felsic (granitic and sedimentary) upper crustal rocks of the Arabian plate form a seismically inactive lower crustal channel below the higher-velocity mafic (basaltic) middle-upper crustal layer of the Iranian crust. Based on existing numerical models, we suggest that the formation of the felsic channel is likely governed by separation (delamination) of the weak felsic upper crust of the subducting Arabian lithosphere and its ductile underplating under rheologically stronger upper-middle crust of the Iranian plate.

Questions Species–area relationships (SARs) are fundamental for understanding biodiversity patterns and are generally well described by a power law with a constant exponent z. However, z‐values sometimes vary across spatial scales. We asked whether there is a general scale dependence of z‐values at fine spatial grains and which potential drivers influence it. Location Palaearctic biogeographic realm. Methods We used 6,696 nested‐plot series of vascular plants, bryophytes and lichens from the GrassPlot database with two or more grain sizes, ranging from 0.0001 m² to 1,024 m² and covering diverse open habitats. The plots were recorded with two widespread sampling approaches (rooted presence = species “rooting” inside the plot; shoot presence = species with aerial parts inside). Using Generalized Additive Models, we tested for scale dependence of z‐values by evaluating if the z‐values differ with gran size and tested for differences between the sampling approaches. The response shapes of z‐values to grain were classified by fitting Generalized Linear Models with logit link to each series. We tested whether the grain size where the maximum z‐value occurred is driven by taxonomic group, biogeographic or ecological variables. Results For rooted presence, we found a strong monotonous increase of z‐values with grain sizes for all grain sizes below 1 m². For shoot presence, the scale dependence was much weaker, with hump‐shaped curves prevailing. Among the environmental variables studied, latitude, vegetation type, naturalness and land use had strong effects, with z‐values of secondary peaking at smaller grain sizes. Conclusions The overall weak scale dependence of z‐values underlines that the power function generally is appropriate to describe SARs within the studied grain sizes in continuous open vegetation, if recorded with the shoot presence method. When clear peaks of z‐values occur, this can be seen as an expression of granularity of species composition, partly driven by abiotic environment.

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