In the last decade, new methods of estimating global species richness have been developed and existing ones improved through the use of more appropriate statistical tools and new data. Taking the ...mean of most of these new estimates indicates that globally there are approximately 1.5 million, 5.5 million, and 7 million species of beetles, insects, and terrestrial arthropods, respectively. Previous estimates of 30 million species or more based on the host specificity of insects to plants now seem extremely unlikely. With 1 million insect species named, this suggests that 80% remain to be discovered and that a greater focus should be placed on less-studied taxa such as many families of Coleoptera, Diptera, and Hymenoptera and on poorly sampled parts of the world. DNA tools have revealed many new species in taxonomically intractable groups, but unbiased studies of previously well-researched insect faunas indicate that 1-2% of species may be truly cryptic.
Aim
The former continental‐scale studies modelled coarse‐grained plant species‐richness patterns (gamma diversity). Here we aim to refine this information for European forests by (a) modelling the ...number of vascular plant species that co‐occur in local communities (alpha diversity) within spatial units of 400 m2; and (b) assessing the factors likely determining the observed spatial patterns in alpha diversity.
Location
Europe roughly within 12°W–30°E and 35–60°N.
Taxon
Vascular plants.
Methods
The numbers of co‐occurring vascular plant species were counted in 73,134 georeferenced vegetation plots. Each plot was classified by an expert system into deciduous broadleaf, coniferous or sclerophyllous forest. Random Forest models were used to map and explain spatial patterns in alpha diversity for each forest type separately using 19 environmental, land‐use and historical variables.
Results
Our models explained from 51.0% to 70.9% of the variation in forest alpha diversity. The modelled alpha‐diversity pattern was dominated by a marked gradient from species‐poor north‐western to species‐rich south‐eastern Europe. The most prominent richness hotspots were identified in the Calcareous Alps and adjacent north‐western Dinarides, the Carpathian foothills in Romania and the Western Carpathians in Slovakia. Energy‐related factors, bedrock types and terrain ruggedness were identified as the main variables underlying the observed richness patterns. Alpha diversity increases especially with temperature seasonality in deciduous broadleaf forests, on limestone bedrock in coniferous forests and in areas with low annual actual evapotranspiration in sclerophyllous forests.
Main conclusions
We provide the first predictive maps and analyses of environmental factors driving the alpha diversity of vascular plants across European forests. Such information is important for the general understanding of European biodiversity. This study also demonstrates a high potential of vegetation‐plot databases as sources for robust estimation of the number of vascular plant species that co‐occur at fine spatial grains across large areas.
The area of habitat patches is a significant factor when determining species‐richness in any given habitat. However, this area effect is not the same for every taxonomic group and can change if is ...considered together with other habitat variables. The main objective of this study was to identify the importance of wetland area for waterbird species‐richness when it is considered in conjunction with other habitat variables. Studies published in the Scopus and Web of Science databases in marine/coastal and inland wetlands were reviewed. A vote‐counting approach was conducted to evaluate how many studies include area as a major variable, and a meta‐analysis was performed to measure the effect size of the relationship between area and species‐richness. Area was a significant predictor of waterbird species‐richness in most of the studies (28 of 40 studies, 70%) as assessed by the vote‐counting approach, and the mean effect size was high (r = 0.81, n = 1 studies) in the meta‐analysis. Few studies reported the shape of the relationship between habitat area and species‐richness, but most reported a positive correlation. Although the species–area relationship is widely recognized, our review shows that an important proportion of studies (30%) also found that other habitat variables were significant variables when they were considered together with habitat area. Consequently, in the case of wetlands, habitat area should be considered in conservation, but not as the only measure of management and restoration if the objective is to conserve waterbird biodiversity by improving species‐richness.
The article presents the results of studying the complexes of terrestrial molluscs of various biotopes in the Gissar Range, Uzbekistan. Taxonomic identification of terrestrial molluscs collected from ...13 biotopes in 4 altitude regions, determination of individual species' density, and assessment of the similarity of species content among biotopes was carried out. Forty-six species of molluscs are found in the studied biotopes. Biotopes no. 5 (along ditches among thickets of grass, under stones), no. 10 (near springs among grasses), and no. 11 (on the banks of small streams among thickets of grasses) were found to maintain the highest species richness. The most common species in the studied biotopes are Cochlicopa lubrica, Vallonia costata, and Pupilla muscorum.
This study examines the complex feedback mechanisms that regulate a positive relationship between species richness and productivity in a longleaf pine-wiregrass woodland. Across a natural soil ...moisture gradient spanning wet-mesic to xeric conditions, two large scale manipulations over a 10-yr period were used to determine how limiting resources and fire regulate plant species diversity and productivity at multiple scales. A fully factorial experiment was used to examine productivity and species richness responses to N and water additions. A separate experiment examined standing crop and richness responses to N addition in the presence and absence of fire. Specifically, these manipulations addressed the following questions: (1) How do N and water addition influence annual aboveground net primary productivity of the midstory/overstory and ground cover? (2) How do species richness responses to resource manipulations vary with scale and among functional groups of ground cover species? (3) How does standing crop (including overstory, understory/midstory, and ground cover components) differ between frequently burned and fire excluded plots after a decade without fire? (4) What is the role of fire in regulating species richness responses to N addition? This long-term study across a soil moisture gradient provides empirical evidence that species richness and productivity in longleaf pine woodlands are strongly regulated by soil moisture. After a decade of treatment, there was an overall species richness decline with N addition, an increase in richness of some functional groups with irrigation, and a substantial decline in species richness with fire exclusion. Changes in species richness in response to treatments were scale-dependent, occurring primarily at small scales (≤10 m²). Further, with fire exclusion, standing crop of ground cover decreased with N addition and non-pine understory/midstory increased in wet-mesic sites. Non-pine understory/midstory standing crop increased in xeric sites with fire exclusion, but there was no influence of N addition. This study highlights the complexity of interactions among multiple limiting resources, frequent fire, and characteristics of dominant functional groups that link species richness and productivity.
Three specimens of Cyathus spp. were collected during a field survey conducted in Tongkoh village and Taman Hutan Raya forest, North Sumatera. The three specimens were preliminary identified leading ...to one species, namely Cyathus montagnei. A description of North Sumatran C.striatus is given. From our knowing, this is the first report of Cyathus montagnei collected in North Sumatera with locality of Karo regency. Hence, further exploration upon identified species and remaining unexplored species is needed to reveal their assemblages or species richness in North Sumatera.
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