Search results for "ECOSYSTEM"
showing 10 items of 1752 documents
Niche filling slows the diversification of Himalayan songbirds.
2013
In Himalayan songbirds, the speciation rate is ultimately set by ecological competition, rather than by the rate of acquisition of reproductive isolation. The beginnings of adaptive radiation and speciation have been widely studied — in Darwin's finches, sticklebacks and cichlid fish, for example — but relatively little is known about what happens next. Specifically, what is the rate-limiting step for the establishment of new species? This seven-year study of the 358 songbird species found on the Himalayan slopes suggests that it is the rates at which new niches are created and occupied that limits diversification, not the rate at which new species form through reproductive isolation. Speci…
West Nile virus in Spain: Forecasting the geographical distribution of risky areas with an ecological niche modelling approach.
2021
West Nile virus (WNV), a well-known emerging vector-borne arbovirus with a zoonotic life cycle, represents a threat to both public and animal health. Transmitted by ornithophilic mosquitoes, its transmission is difficult to predict and even more difficult to prevent. The massive and unprecedented number of human cases and equid outbreaks in Spain during 2020 interpellates for new approaches. For the first time, we present an integrate analysis from a niche perspective to provide an insight to the situation of West Nile disease (WND) in Spain. Our modelling approach benefits from the combined use of global occurrence records of outbreaks of WND in equids and of its two alleged main vectors i…
Predicting future thermal habitat suitability of competing native and invasive fish species: From metabolic scope to oceanographic modelling
2015
Global increase in sea temperatures has been suggested to facilitate the incoming and spread of tropical invaders. Here, we determined the effect of temperature on the aerobic metabolic scope of two competing fish species, one native and one invasive, and we predicted their future thermal habitat suitability.
Metazoan parasite communities and diet of the velvet belly lantern shark Etmopterus spinax (Squaliformes: Etmopteridae): a comparison of two deep-sea…
2014
By combining an examination of stomach contents yielding a snapshot of the most recent trophic niche and the structure of parasite communities reflecting a long-term feeding niche, this study aimed at gaining more comprehensive information on the role of the small-sized deep-water velvet belly lantern shark Etmopterus spinax in the local food webs of the Galicia Bank and the canyon and valley system of the Aviles Canyon, which have been both proposed for inclusion in the Natura 2000 network of protected areas. As far as is known, this study provides the first comparative parasite infracommunity data for a deep-sea shark species. Component parasite communities in E. spinax were relatively ri…
Will the invasive western conifer seed bug Leptoglossus occidentalis Heidemann (Hemiptera: Heteroptera: Coreidae) seize all of Europe?
2008
In our day, thanks to high-speed transport systems, people are moving living species (intentionally or not) across ecosystems and countless borders. As we know, most introduced species usually do not survive, because they find neither a tolerable environment nor an available ecological niche. Sometimes, successful establishment may also require multiple introductions (Balcom 2004).
Resistant Microbial Cooccurrence Patterns Inferred by Network Topology
2015
ABSTRACT Although complex cooccurrence patterns have been described for microbes in natural communities, these patterns have scarcely been interpreted in the context of ecosystem functioning and stability. Here we constructed networks from species cooccurrences between pairs of microorganisms which were extracted from five individual aquatic time series, including a dystrophic and a eutrophic lake as well as an open ocean site. The resulting networks exhibited higher clustering coefficients, shorter path lengths, and higher average node degrees and levels of betweenness than those of random networks. Moreover, simulations demonstrated that taxa with a large number of cooccurrences and place…
Revisiting the role of top-down and bottom-up controls in stabilisation of nutrient-rich plankton communities
2019
Understanding the conditions for successful control of phytoplankton by zooplankton in eutrophic ecosystems is a highly important research area with a wide implementation of mathematical modelling. Theoretical models generally predict destabilisation of food webs in eutrophic environments with large-amplitude oscillations of population densities which would eventually result in species extinction. On the other hand, these theoretical predic- tions are often at odds with ecological observations demonstrating stable dynamics even for a high nutrient load. This apparent discrepancy is known in the literature as Rosen- zweig’s “paradox of enrichment”. Recent theoretical works emphasize a crucia…
Ocean acidification through the lens of ecological theory
2015
© 2015 by the Ecological Society of America. Ocean acidification, chemical changes to the carbonate system of seawater, is emerging as a key environmental challenge accompanying global warming and other humaninduced perturbations. Considerable research seeks to define the scope and character of potential outcomes from this phenomenon, but a crucial impediment persists. Ecological theory, despite its power and utility, has been only peripherally applied to the problem. Here we sketch in broad strokes several areas where fundamental principles of ecology have the capacity to generate insight into ocean acidification's consequences. We focus on conceptual models that, when considered in the co…
Shape and size in phytoplankton ecology: do they matter?
2007
This paper summarises the outcomes of the 14th Workshop of the International Association of Phytoplankton Taxonomy and Ecology (IAP). The authors mostly addressed their contributions on the following topics: morphological and morpho-functional descriptors of phytoplankton, size and shape structure of phytoplankton related to different kinds of environmental variables and the role of morphological and physiological plasticity of phytoplankton in maintaining the (apparently) same populations under different environmental conditions. Case studies from different kinds of aquatic environments (deep and shallow lakes, reservoirs with different age, purpose and trophic state, floodplain wetlands m…
Changes in community composition determine recovery trajectories from multiple agricultural stressors in freshwater ecosystems
2020
AbstractPesticides have been identified worldwide as a threat for aquatic biodiversity due to their widespread use in agriculture and their capacity to reach freshwater ecosystems. Very little is known about the consequences of pesticide mixtures targeting different organism groups on community dynamics. Especially, how horizontal changes within one trophic level are propagated vertically across the food web has been rarely investigated. To get insight on the effects of pesticide mixtures on community dynamics, we performed a mesocosm experiment manipulating three common agricultural stressors: chlorpyrifos (an insecticide), diuron (an herbicide) and nutrients. The results of this study sho…