Search results for "SPECIES RICHNESS"

2010

The diversity–stability hypothesis states that current losses of biodiversity can impair the ability of an ecosystem to dampen the effect of environmental perturbations on its functioning. Using data from a long-term and comprehensive biodiversity experiment, we quantified the temporal stability of 42 variables characterizing twelve ecological functions in managed grassland plots varying in plant species richness. We demonstrate that diversity increases stability i) across trophic levels (producer, consumer), ii) at both the system (community, ecosystem) and the component levels (population, functional group, phylogenetic clade), and iii) primarily for aboveground rather than belowground pr…

Re-establishment of zooplankton communities in temporary ponds after autumn flooding: Does restoration age matter?

2012

Abstract In temporary ponds, reestablishment of zooplankton communities depends on recruitment from the egg bank, the arrival of dispersers from within the region, and on successful establishment of newly arrived species following interaction with local abiotic and biotic factors. When the ponds dry up, zooplankton species may survive as dormant eggs, and since not all eggs hatch in the next season, eggs will accumulate in the sediment over time, representing an archive of the pond's historical biodiversity. To study the effect of “restoration age” (the time since a water body was restored), we studied groups of ponds that were restored in different years (1998, 2003 and 2007). The restorat…

Importance of Climate Change for the Ranges, Communities and Conservation of Birds

2004

Publisher Summary This chapter focuses on the effects of global climate change on the size and position of geographic ranges and the richness and composition of bird communities. Plenty of evidence demonstrates that range boundaries of birds are correlated with climatic factors. In general, the northern range limit of species seems to be influenced rather by abiotic factors such as cold temperatures. The southern range limit of species appears to be determined by climatic factors such as heat or lack of water in arid regions and by biotic factors in more humid regions. For communities, increases in species richness are predicted for northern latitude and high-elevation sites and declines of…

Ammonoid recovery after the Permian-Triassic mass extinction: a re-exploration of morphological and phylogenetic diversity patterns.

2013

The explosive ammonoid rediversification after the Permian–Triassic mass extinction is now well understood in terms of taxonomic richness and biogeography. Using an updated dataset of Early Triassic ammonoids, we compare morphological disparity and taxonomic richness patterns at the regional and global scales. Disparity evolved similarly at both scales, suggesting a global influence of abiotic factors. Morphological diversification occurred early in the Smithian and a marked contraction of the morphospace took place during the end-Smithian extinction. We confirm that trends in disparity and richness were decoupled during the Griesbachian and Dienerian. Three macroevolutionary processes may …

The importance of the moss layer in sustaining biological diversity of Gamasina mites in coniferous forest soil

2008

Summary The feather moss layer of boreal coniferous forests is known to buffer the underlying soil temperature and to be a major component in the nitrogen and phosphorus cycles by efficient scavenging of nutrients from throughfall and direct precipitation. Through indirect or direct effects the feather moss layer may also play a significant role in forming soil organism communities. In this 4-year experimental field study, the predatory Gamasina mite diversity was estimated in plots where the feather moss layer was removed or disturbed by turning over, in relation to that in control plots. Species richness, Shannon's diversity and equitability in spring but not autumn were decreased when th…

Environmental drivers of breeding sites in blackfly species of medical and veterinary importance in eastern Spain

2021

Geographical distribution and abundance of the pupae of six blackfly species of medical and veterinary concern were studied in eastern Spain according to three different sets of explanatory variables including in-stream variables, both (i) abiotic (i.e., physicochemical) and (ii) biotic (i.e., richness and abundance of either taxonomically or ecologically close related taxa), as well as (iii) meteorological and landscape variables. The results showed specific habitat requirements for pupation in Simulium (Boophthora) erythrocephalum (De Geer, 1776) and Simulium (Wilhelmia) equinum (Linnaeus, 1758), two of the six species studied regarding elevation and temperature. While the rest of the spe…

First insights into weed communities of rice agrocoenoses in southern Thailand

2015

The study presents the results of geobotanical investigations conducted in rice fields in southern Thailand in 2013. It is focussed on the classification of plant communities poorly investigated from a geobotanical standpoint. Altogether 125 phytosociological relevés were collected, using the Braun-Blanquet method. We noted more than 100 species in the vegetation plots, including many rare ones. We classified the vegetation into seven communities, including six associations. Five associations are proposed as new: Nymphaeetum nouchali, Fimbristylido miliaceae-Sphenocleetum zeylanicae, Ischaemo rugosi-Cyperetum pulcherrimi, Pentapeto phoeniceae-Aeschynomenetum indicae and Marsileetum minutae.…

Relationships Between Birds and Habitats in Latvian Farmland

2001

This point-count based study (1995-99) provides information on the avifauna of different farmland habitats in Latvia. Ordinations identify the main gradients within the species composition pattern: from arable land to natural habitats and from woodland across open, dry areas to wet meadowlands with rivers and ponds. Regression models describing the relationship between species richness and habitat show that the best positive predictors of species richness are woodland, scrub, natural meadows, unfarmed patches such as piles of stones or brushwood, and ponds. Regression models of the habitat affinities of the 30 most frequently recorded bird species are used to describe the present-day situat…

Optimal timing of power line rights-of-ways management for the conservation of butterflies

2012

Habitat loss, fragmentation, and degradation are the main threats to biodiversity. Human activities also create new habitat types that might fulfil ecological requirements for a variety of species. This study investigates whether the vegetation clearing (=shrub and tree cutting) on drained mire patches on power line rights-of-ways (ROWs) keep plant communities in an early successional stage and thus provide habitats for mire specialist and non-mire butterflies. It was further studied what would be the optimal clearing interval in terms of butterfly species richness and abundance. The results show that tree height, especially the height of birch, increases linearly over the 7-year period fol…

Corrigendum to “Conservation value of forest plantations for bird communities in western Kenya” [Forest Ecol. Manag. 255 (2008) 3885–3892]

2009

A re-analysis of the bird data revealed a mistake within the database query. Only bird individuals that were heard were integrated in the results leading to lower total richness and number of individuals. In total 115 species and 13,331 individuals were detected of which 41 were forest specialists (43% of all individuals), 40 forest generalists (41%) and 34 forest visitors (16%). The statistical analyses remain very similar. We recorded significant differences in mean bird species richness, number of individuals and relative species richness among the five forest types (Table 1). Multiple pairwise comparisons showed significantly higher numbers of species in natural forest, mixed indigenous…