نتایج جستجو برای: trophic structure
تعداد نتایج: 1579737 فیلتر نتایج به سال:
An updated trophic model of the southern Benguela ecosystem in the period 2004−2008 was constructed, complementing trophic models for earlier periods. The model represents the trophic structure of the system after a southward shift of major resources. There was an increase in biomass of small pelagic fish and cephalopods between the 1980s and 2004–2008 periods, accompanied by declines in severa...
Humans are changing the biosphere by exerting pressure on land via different land uses with variable intensities. Quantifying the relative importance of the land-use composition and intensity for communities may provide valuable insights for understanding community dynamics in human-dominated landscapes. Here, we evaluate the relative importance of the land-use composition versus land-use inten...
We investigate how four types of interference competition - which alternatively affect foraging, metabolism, survival, and reproduction - impact the ecology and evolution of size-structured populations. Even though all four types of interference competition reduce population biomass, interference competition at intermediate intensity sometimes significantly increases the abundance of adult indi...
Commonness of organisms typically fluctuates through time, and understanding such fluctuations has long been an important part of ecological research. Studies at paleontological timescales provide a perspective on how changes in population size might affect community structure over millions of years. To overcome the obstacle that population size parameters such as abundance are difficult to det...
Few studies have evaluated phenotypic plasticity at the community level, considering, for example, plastic responses in an entire species assemblage. In addition, none of these studies have addressed the relationship between phenotypic plasticity and community structure. Within this context, here we assessed the magnitude of seasonal changes in digestive traits (seasonal flexibility), and of ch...
An ongoing debate in evolutionary ecology concerns the relative role of contemporary vs. historical processes in determining local species richness and community structure. At sites along a 4 Mya geological chronosequence on Hawai‘i, Moloka‘i and Kaua‘i, numerous extrinsic factors can be held constant, but ecosystem fertility and nutrient availability are low, both very young and very old sites...
Tropical rain forest fragmentation affects biotic interactions in distinct ways. Little is known, however, about how fragmentation affects animal trophic guilds and their patterns of interactions with host plants. In this study, we analyzed changes in biotic interactions in forest fragments by using a multitrophic approach. For this, we classified arthropods associated with Heliconia aurantiaca...
Comparative research on food web structure has revealed generalities in trophic organization, produced simple models, and allowed assessment of robustness to species loss. These studies have mostly focused on free-living species. Recent research has suggested that inclusion of parasites alters structure. We assess whether such changes in network structure result from unique roles and traits of ...
Plant diversity is predicted to be positively linked to the diversity of herbivores and predators in a foodweb. Yet, the relationship between plant and animal diversity is explained by a variety of competing hypotheses, with mixed empirical results for each hypothesis. We sampled arthropods for over a decade in an experiment that manipulated the number of grassland plant species. We found that ...
Since the collapse of the pelagic fisheries off southwest Africa in the late 1960s, jellyfish biomass has increased and the structure of the Benguelan fish community has shifted, making the bearded goby (Sufflogobius bibarbatus) the new predominant prey species. Despite increased predation pressure and a harsh environment, the gobies are thriving. Here we show that physiological adaptations and...
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