Search results for " evolution."

Niche relations among dung-inhabiting beetles.

1976

The whole dung-inhabiting (adult) beetle community living in southern Finland was studied with reference to the seasonal (6 summer months), macrohabitat (open field, half-open pine forest and closed spruce forest) and successional (30 days) gradients. The material comprised 50 coprophagous and 129 carnivorous species, represented by 26,650 and 35,850 individuals, respectively. The most important characteristics of each species are given in an Appendix.In the coprophages the species-abundance relations fitted the lognormal distribution well, but in the carnivores the distribution was strikingly less even. A great number of other differences (see below) apparent between the two trophic groups…

Persistence of submerged macrophytes in a drying world: Unravelling the timing and the environmental drivers to produce drought-resistant propagules

2018

Comparing stressor-specific indices and general measures of taxonomic composition for assessing the status of boreal lacustrine macrophyte communities

2013

Abstract Biotic communities are increasingly used to assess and monitor aquatic ecosystems with two fundamentally contrasting approaches: (i) responses sensitive to, and indicative of specific stressors; and (ii) general measures of community change. For assessment of lacustrine macrophyte communities, we compared three trophy-related and one water level fluctuation-related stressor-specific indices (SSIs) with three general measures of taxonomic composition (MTC), using data from 48 reference, 33 eutrophicated and 24 water level regulated boreal lakes. Our hypothesis was that MTCs would yield robust ecological quality estimates across these differing stress-gradients, while the SSIs would …

The River Valleys as Biodiversity Reservoirs for Land Snails in Highly Anthropic Areas – The Case of Cisnădie River (Romania)

2016

Abstract This study focuses on the snail fauna of a river valley passing through two closely located settlements. Thirty six species of terrestrial gastropods were identified. Species such as Macrogastra borealis, Alinda fallax, Alinda viridana, Bulgarica vetusta, Monachoides vicinus, Drobacia banatica, are present along the river and abundant in the sampling stations downstream of Cisnădie town. The high specific diversity and the presence of typical forest species demonstrate the presence of fragments of habitat that can preserve populations of terrestrial gastropods, underlining the importance of river valleys in conservation and dispersion of these species.

Possible effects of global environmental changes on Antarctic benthos: a synthesis across five major taxa

2012

Because of the unique conditions that exist around the Antarctic continent, Southern Ocean (SO) ecosystems are very susceptible to the growing impact of global climate change and other anthropogenic influences. Consequently, there is an urgent need to understand how SO marine life will cope with expected future changes in the environment. Studies of Antarctic organisms have shown that individual species and higher taxa display different degrees of sensitivity to environmental shifts, making it difficult to predict overall community or ecosystem responses. This emphasizes the need for an improved understanding of the Antarctic benthic ecosystem response to global climate change using a multi…

SPACE USE, CIRCADIAN ACTIVITY PATTERN, AND MATING SYSTEM OF THE NOCTURNAL TREE RAT THALLOMYS NIGRICAUDA

2004

We present results of a radiotracking study of the black-tailed tree rat Thallomys nigricauda, based on 3 males and 4 females in the breeding season and 2 males and 5 females in the nonbreeding season. The study was conducted in the southern Kalahari thornveld, South Africa, a savanna landscape of acacia trees and patchy acacia bush. Nocturnal activity patterns, vegetation use, space use, and interactions were followed for 8–17 days. During the breeding season, males were active with 2 synchronous activity peaks shortly after sunset and late at night. Home ranges included the nests of 8–10 females, 6 different daytime resting places, and 3–5 areas of high activity. Males were mobile within …

Combining environmental DNA and species distribution modeling to evaluate reintroduction success of a freshwater fish

2019

Active species reintroduction is an important conservation tool when aiming for the restoration of biological communities and ecosystems. The effective monitoring of reintroduction success is a crucial factor in this process. Here, we used a combination of environmental DNA (eDNA) techniques and species distribution models (SDMs) to evaluate the success of recent reintroductions of the freshwater fish Alburnoides bipunctatus in central Germany. We built SDMs without and with eDNA presence data to locate further suitable reintroduction sites and potentially overlooked populations of the species. We successfully detected eDNA of A. bipunctatus at all reintroduction sites, as well as several a…

On the tolerance of charophytes to high-nitrate concentrations

2017

Currently a debate exists about whether the reduced growth of macrophytes with increased nitrogen loading in shallow ecosystems is determined by ecological or physiological factors. To discover whe...

2019

Local support is important for the longevity of conservation initiatives. The literature suggests that perceptions of ecological effectiveness, social impacts, and good governance will influence levels of local support for conservation. This paper examines these relationships using data from a survey of small‐scale fishermen in 11 marine protected areas from six countries in the Mediterranean Sea. The survey queried small‐scale fishermen regarding perceptions and support for conservation. We constructed composite scores for three categories of perceptions—ecological effectiveness, social impacts, and good governance—and tested the relationship with levels of support using ordinal regression…

Testing the usefulness of habitat corridors in mitigating the negative effects of fragmentation: the soil faunal community as a model system

2004

Abstract The corridor hypothesis predicts that habitat corridors should attenuate the negative effects of fragmentation on populations or communities by enhancing the dispersal of organisms between the habitat fragments (the ‘rescue effect’). In the present 12-month mesocosm experiment, this hypothesis was tested using the soil micro- and mesofaunal community in humus patches—either connected or unconnected with humus corridors to each other—as a model system. Of particular interest was to explore whether faunal groups with differing life strategies (e.g. in trophic position and dispersal capacity) would differ in their responses to the corridors. The results showed that enchytraeid worms w…