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Litter decomposition in terrestrial habitats is affected by many factors, including temperature, moisture, and nutrient and organic composition of litter. Among organic components, lignin is the primary controlling factor of decomposition rates of surface litter during the later phase of decomposition in most habitats and during the initial phase in warm, moist habitats (i.e., those with a high actual evapotranspiration, AET). In habitats with moderate AET's, we suggest that the decreased control by lignin over annual decomposition rates of surface litter is due, at least in part, to a significant periodic or seasonal influence of other carbonbased plant secondary metabolites over rates in the initial phase of decomposition....
Climate warming will continue alongside human modification of the landscape. Therefore, studying systems modified by land use may highlight factors that mitigate or exacerbate predicted biological responses to ongoing climate warming. Using historical museum specimen records and recent field surveys, I examine temporal patterns in the ecological dynamics of the small mammal fauna on five mountain ranges in central Utah over time intervals of 27-53 years during the past century. This landscape was heavily modified by livestock grazing early in the twentieth century and since then has witnessed a steady decline in grazing intensity. In general, at regional and landscape scales, species preferring mesic habitats increased...
Field patterns and experimental results suggest that the effect of zooplankton grazing on the abundance of large colonial cyanobacteria may differ strongly from case to case. In this article we present an extensive analysis of a model that describes the competition between cyanobacteria of the Oscillatoria group and green algae exploited by Daphnia. In particular, we study the response of the model to changes in the nutrient concentration and predation by zooplanktivorous fish. The analysis is repeated for an array of different assumptions on the nutritional value of cyanobacteria and selectivity of zooplankton grazing. When fish predation pressure is so high that Daphnia density is negligible, there is competitive...
Field patterns and experimental results suggest that the effect of zooplankton grazing on the abundance of large colonial cyanobacteria may differ strongly from case to case. In this article we present an extensive analysis of a model that describes the competition between cyanobacteria of the Oscillatoria group and green algae exploited by Daphnia. In particular, we study the response of the model to changes in the nutrient concentration and predation by zooplanktivorous fish. The analysis is repeated for an array of different assumptions on the nutritional value of cyanobacteria and selectivity of zooplankton grazing. When fish predation pressure is so high that Daphnia density is negligible, there is competitive...