Search results for "ECOSYSTEM"
showing 10 items of 1752 documents
Woody plants and the prediction of climate-change impacts on bird diversity.
2010
Current methods of assessing climate-induced shifts of species distributions rarely account for species interactions and usually ignore potential differences in response times of interacting taxa to climate change. Here, we used species-richness data from 1005 breeding bird and 1417 woody plant species in Kenya and employed model-averaged coefficients from regression models and median climatic forecasts assembled across 15 climate-change scenarios to predict bird species richness under climate change. Forecasts assuming an instantaneous response of woody plants and birds to climate change suggested increases in future bird species richness across most of Kenya whereas forecasts assuming str…
River bioassessment and the preservation of threatened species: Towards acceptable biological quality criteria
2010
Abstract A central objective of environmental management is to maintain biodiversity, including populations of threatened species. Freshwater ecosystems are increasingly assessed by their biotic properties, but whether the resulting classifications of biotic condition are sufficient to protect species with conservation status has received very little consideration. We used data from 225 reference and impacted river sites from Finland to examine whether the occurrence and abundance of threatened macroinvertebrate species (TS) are associated with a commonly used estimate of biological condition (Observed-to-Expected number of predicted taxa of macroinvertebrates or O/E-ratio of taxonomic comp…
Regulation of decomposer community structure and decomposition processes in herbicide stressed humus soil
1997
Abstract Regulation of soil decomposer community structure and ecosystem processes, such as nutrient cycling, under herbicide stress was studied in a microcosm experiment. For the experiment, coniferous forest soil was defaunated and put into the microcosms. In the microcosms two different food webs including microbes, nematodes, tardigrades and oribatid mites, either with or without predatory mesostigmatid mites, were reconstructed. Half of the microcosms were stressed with a herbicide (active ingredient was terbuthylazine). During the 57 weeks incubation community structure of decomposers and nitrogen mineralisation were studied at five destructive samplings and two water irrigations. Soi…
Efectos del cambio climático en las helmintiasis animales y zoonóticas
2008
Current knowledge of animal and zoonotic helminthiases in which effects of climate change have been detected is reviewed. Climate variables are able to affect the prevalence, intensity and geographical distribution of helminths, directly influencing free-living larval stages and indirectly influencing mainly invertebrate, but also vertebrate, hosts. The impact of climate change appears to be more pronounced in trematodes, and is mainly shown by increased cercarial production and emergence associated with global warming. Fascioliasis, schistosomiasis (S. japonicum) and cercarial dermatitis caused by avian schistosomes have been the focus of study. Alveolar echinococcosis is currently the onl…
Effect of pentachlorophenol on predator-prey interaction of two rotifers
1997
Abstract The effect of pentachlorophenol (PCP) on the predator-prey relationship of two rotifers (Asplanchna girodi and Brachionus calyciflorus) was studied using Asplanchna predatory behavior as an endpoint. The experimental design included three treatments: prey and predator exposure, only prey exposure, and only predator exposure. This enabled us to distinguish toxic effects on the predator from those on the prey and to detect interactions. The main toxic effects observed were on the predator and involved the number of predator-prey encounters. Encounters decreased in a dose-dependent manner, with a no observed effect threshold at 0.11 mg PCP l−1. Decrease in encounter rate reduced the n…
Decomposer animals and bioremediation of soils
1998
Abstract Although microorganisms are degrading the contaminants in bioremediation processes, soil animals can also have important — while usually an indirect — role in these processes. Soil animals are useful indicators of soil contamination, both before and after the bioremediation. Many toxicity and bioavailability assessment methods utilizing soil animals have been developed for hazard and risk-assessment procedures. Not only the survival of the animals, but also more sensitive parameters like growth, reproduction and community structure have often been taken into account in the assessment. The use of bioassays together with chemical analyses gives the most reliable results for risk anal…
Identification problems of arid environments in the Neogene–Quaternary mammal record of Spain
2006
Abstract In this work, we investigate if broadly used methodologies are adequate to detect periods of aridity based on the Spanish fossil record and try to infer which of them were more or less severe. Thus, we present a qualitative statistical approach to two popular palaeoecological methodologies: ecological diversity and cenograms. Discriminant models, derived from modern localities of known biome, determined the probable biomes of Neogene–Quaternary fossil assemblages. Principal component analyses (PCA) provided additional inference on their ordination within an aridity gradient. While models work adequately with modern faunas, the analyses of the palaeocommunities showed that their eco…
Do small marinas drive habitat specific impacts? A case study from Mediterranean Sea.
2011
Many human activities add new structures to the marine landscape. Despite the fact that human structures cause some inevitable impacts, surprisingly little information exists on the effects of marina on natural marine assemblages. The aim of this paper is to assess habitat-specific response of benthic sessile organisms of rocky shores in relation to the presence of a small marina. Sampling was carried out at three coastal habitats (midshore, lowshore and subtidal) by means of visual censuses adopting an after-control-impact (ACI) experimental design. It appears that the marina affects the structure and composition of benthic communities of both the midshore and the lowshore. Little effect w…
Evaluation, Analysis and Perception of Sustainable Forest Management Through the Lens of the PEFC Forest Certification Using Two Case Studies in Sici…
2019
Sustainable forest management has reached a common understanding between scientific and technical definitions. A series of criteria and indicators have been implemented for monitoring the effectiveness of the management in functional and structural terms, and to evaluate its effects on ecosystem services of forests. Currently, Sicily has no forest areas with certification of sustainable forest management and in order to evaluate the diffusion of knowledge of certification schemes and their importance in SFM, a questionnaire survey was carried out during a foresters' workshop on the island. The possibility of applying the criteria and indicators of PEFC certification of sustainable forest ma…
Agricultural landscapes and biodiversity conservation: a case study in Sicily (Italy)
2015
The diversity of life is made up not only of the diversity of plants and animal species, habitats and ecosystems, but also of the diversity of human cultures. These diversities interact with one another in complex ways and express the mutual adaptation between humans and the environment at local level. Sicilian traditional agro-ecosystems, due to the history of the territory and the resulting social and economic context, are configured in a heterogeneous mosaic rich in residual features of environmental value, which enhance the connectivity of the ecological network and support a high proportion of species that are rare or of conservation concern. As a case study we analyzed the characteris…