Search results for "SPECIES RICHNESS"
showing 10 items of 427 documents
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…
Biogenic habitat shifts under long-term ocean acidification show nonlinear community responses and unbalanced functions of associated invertebrates
2019
Este artículo contiene 8 páginas, 4 figuras.
Nitrogen and phosphorus budgets in experimental grasslands of variable diversity.
2007
Previous research has shown that plant diversity influences N and P cycles. However, the effect of plant diversity on complete ecosystem N and P budgets has not yet been assessed. For 20 plots of artificially established grassland mixtures differing in plant diversity, we determined N and P inputs by bulk and dry deposition and N and P losses by mowing (and subsequent removal of the biomass) and leaching from April 2003 to March 2004. Total deposition of N and P was 2.3 +/- 0.1 and 0.2 +/- 0.01 g m(-2) yr(-1), respectively. Mowing was the main N and P loss. The net N and P budgets were negative (-6.3 +/- 1.1 g N and -1.9 +/- 0.2 g P m(-2) yr(-1)). For N, this included a conservative estimat…
Parasite assemblages of crucian carp (Carassius carassius) – is depauperate composition explained by lack of parasite exchange, extreme environmental…
2005
Recent studies on parasite communities have considered the factors which contribute to variability in parasite infections among populations of one host species. This paper examined parasite assemblages of crucian carp (Carassius carassius) in a natural set-up of two distinctive environments inhabited by the same host species and differing in respect to composition of other fish species: ponds, where extreme conditions prevent other fish species from occurring and lakes, where crucian carp coexist with other fish species. Our aim was to evaluate the significance of parasite exchange, environmental conditions and host suitability for the depauperate parasite assemblages observed in pond cruci…
Fish population size, and not density, as the determining factor of parasite infection: a case study.
2004
The diversity and abundance of parasites vary widely among populations of the same host species. These infection parameters are, to some extent, determined by characteristics of the host population or of its habitat. Recent studies have supported predictions derived from epidemiological models regarding the influence of host population density: parasite abundance and parasite species richness are expected to increase with increasing host population density, at least for directly transmitted parasites. Here, we test this prediction using a natural system in which populations of the crucian carp, Carassius carassius (L.), occur alone, with no other fish species, in a series of 9 isolated pond…
Habitat preferences of bats in a rural area of Sicily determined by acoustic surveys
2009
<strong>Abstract</strong> The bat fauna of a 60 km<sup>2</sup> wide area representing the typical rural landscape of inland Sicily and including the small &ldquo;Rocche di Entella&rdquo; karstic plateau (Natural Reserve and SAC) was surveyed between May 2006 and September 2007. Sampling was carried out at 95 sites, distributed proportionally in six main habitats. Bat calls were time-expanded with a D980 bat detector and then identified to species level by a Discriminant Function Analysis. We recorded 305 bat passes and identified 96.4% of recorded calls. Moon phase, cloud cover and their interaction did not affect total bat activity, nor did the sampling peri…
Phytoplankton dynamics in permanent and temporary Mediterranean waters: is the game hard to play because of hydrological disturbance?
2012
Only few scientific investigations have been carried out, to our knowledge, on phytoplankton in Mediterranean temporary ponds. To test the hypothesis that climate forcing is the main factor affecting dynamics and structure of planktic algae in these peculiar ecosystems, and to assess the importance of human impacts on this basic component of the aquatic biota, phytoplankton structure and dynamics were analysed in two temporary, long lasting (9 months), ponds, and in a permanent one. The three studied water bodies can be classified as mesoeutrophic, which show extended macrophyte beds and are subjected to one or more human impacts, such as eutrophication, fish and plant introduction, and gar…