Search results for "richness"
showing 10 items of 447 documents
Biodiversity of wood-decay fungi in Italy
2011
Abstract Current knowledge about Italian wood-decay fungi (Basidiomycota and Ascomycota) is surveyed: 1582 taxa belonging to Ascomycota (341) and Basidiomycota (1241) have been reported, including 23 species new to science of Basidiomycota described from Italy within the last five years. Evaluating diversity of wood-decay fungi can provide a more accurate estimation of species richness for fungi which are an important functional component of ecosystems. Aphyllophoroid and Ascomycota species play an important role in habitat conservation and management. Sardinia, Sicily, the Alps and the Apennines are “hot spots” for wood-decay Basidiomycota in Italy.
Comparing the effects of introduced signal crayfish and native noble crayfish on the littoral invertebrate assemblages of boreal lakes
2015
The introduced North American signal crayfish Pacifastacus leniusculus (Dana) has replaced the native noble crayfish (Astacus astacus) in many European freshwaters and can be considered a new component of these ecosystems. The 2 species are apparently similar in many respects, but their ecological equivalence is uncertain and has been little investigated, especially at the whole-lake scale. We compared the effects of the 2 species on the abundance, species richness, and composition of littoral macroinvertebrate assemblages in a set of small- and mediumsized boreal lakes, which included 8 lakes with noble crayfish, 8 lakes with signal crayfish, and 8 lakes without crayfish. We collected semi…
Bacteriophage richness reduces bacterial niche overlap in experimental microcosms
2015
Antagonistic interactions such as competition and predation shape the structure and dynamics of ecological communities. Their combined effects can affect the species richness within a particular trophic level. Despite theory linking the complementarity of interactions across trophic levels and ecosystem functioning, there is a shortage of empirical tests of such predictions. We present an experimental investigation of these combined effects within a bacteria-phage interaction network. We measured the biomass yield of combinations of bacterial strains under increasing levels of bacteriophage richness. Our results show an increasing impact of phage on bacteria with increasing phage diversity.…
Influences of landscape structure on diversity of beetles associated with bracket fungi in Brazilian Atlantic Forest
2015
Abstract Brazilian Atlantic forest ecosystem is a global biodiversity hotspot. We studied the effects of area, connectivity and habitat quality of conservation areas on the diversity of beetles associated with basidiomes of wood-decaying fungi. Moreover, we analyzed the beetles' composition to verify what the process that produces the differentiation between the patches (β diversity). Species richness of fungivorous beetles increased the larger the area and the better the connectivity of conservation areas; however, neither area nor connectivity had an independent effect on beetle richness. Furthermore, the fungivorous beetle community was affected by the reduction in resource availability …
Relationship between soil microarthropod species diversity and plant growth does not change when the system is disturbed
2002
Soil microarthropods influence vital ecosystem processes, such as decomposition and nutrient mineralisation. There is evidence, however, that proper functioning of ecosystems does not require the presence of all its constituent species, and therefore some species can be regarded as functionally redundant. It has been proposed that species redundancy can act as an insurance against unfavourable conditions, and that functionally redundant species may become important when a system has faced a disturbance (the “insurance hypothesis”). We conducted a laboratory microcosm experiment with coniferous forest soil and a seedling of silver birch (Betula pendula). A gradient of microarthropod diversit…
Hot spots, indicator taxa, complementarity and optimal networks of taiga
2000
If hot spots for different taxa coincide, priority-setting surveys in a region could be carried out more cheaply by focusing on indicator taxa. Several previous studies show that hot spots of different taxa rarely coincide. However, in tropical areas indicator taxa may be used in selecting complementary networks to represent biodiversity as a whole. We studied beetles (Coleoptera), Heteroptera, polypores or bracket fungi (Polyporaceae) and vascular plants of old growth boreal taiga forests. Optimal networks for Heteroptera maximized the high overall species richness of beetles and vascular plants, but these networks were least favourable options for polypores. Polypores are an important gro…
Mammal assemblage composition predicts global patterns in emerging infectious disease risk
2021
Abstract As a source of emerging infectious diseases, wildlife assemblages (and related spatial patterns) must be quantitatively assessed to help identify high‐risk locations. Previous assessments have largely focussed on the distributions of individual species; however, transmission dynamics are expected to depend on assemblage composition. Moreover, disease–diversity relationships have mainly been studied in the context of species loss, but assemblage composition and disease risk (e.g. infection prevalence in wildlife assemblages) can change without extinction. Based on the predicted distributions and abundances of 4466 mammal species, we estimated global patterns of disease risk through …
Mapping and determinism of soil microbial community distribution across an agricultural landscape.
2015
Article en open access; International audience; Despite the relevance of landscape, regarding the spatial patterning of microbial communities and the relative influence of environmental parameters versus human activities, few investigations have been conducted at this scale. Here, we used a systematic grid to characterize the distribution of soil microbial communities at 278 sites across a monitored agricultural landscape of 13km(2). Molecular microbial biomass was estimated by soil DNA recovery and bacterial diversity by 16S rRNA gene pyrosequencing. Geostatistics provided the first maps of microbial community at this scale and revealed a heterogeneous but spatially structured distribution…
Comparing modified biological monitoring working party score system and several biological indices based on macroinvertebrates for water-quality asse…
2005
Abstract Macroinvertebrate communities from the lower Nysa Klodzka River catchment, southern Poland, were analyzed seasonally, in order to assess changes in their composition and structure, in relation to water quality. Two major groups of sites, differing in both morphological structure and taxonomical composition by cluster analysis, were identified within the catchment area. Wider and deeper sites, located along the Nysa Klodzka River, were associated with the dominance of Chironomidae. Sites assigned along tributaries were characterized by a diversified structure of dominant taxa, including Oligochaeta, Hirudinea, Crustacea, Trichoptera, Ephemeroptera and Diptera. The performance of the…
Anthropogenic disturbance and diversity of species: polypores and polypore-associated beetles in forest, forest edge and clear-cut
2005
In boreal coniferous forests, artificial edges often modify the habitat, increasing the likelihood that the diversity and composition of species changes. This study examined the assemblage of polypores and polypore-associated beetles at the edge of mature managed spruce-dominated forests and clear-cuts. The highest number of polypore occurrences and the greatest diversity of polypore species occurred at the clear-cut. In south-facing edges polypores occurred closer to the edge both in clear-cut and in forest than in the north-facing edges. The number of polypore-associated beetle individuals was greatest in the clear-cut, but there was no effect of edge on species richness of beetles. Orien…