Understanding drivers of ecosystem primary production is a foundational question in ecology that grows in importance with anthropogenic stresses (e.g., climate change). Traditionally, ecosystem production is considered to be abiotically... more
Understanding drivers of ecosystem primary production is a foundational question in ecology that grows in importance with anthropogenic stresses (e.g., climate change). Traditionally, ecosystem production is considered to be abiotically controlled at large spatial scales (e.g., precipitation, temperature, etc.), which underlies forecasting climate change impacts. Using a “common garden” experiment over 10 years at two sites with the same plant and grasshopper species, we show that primary production is strongly influenced by biotic factors (herbivory and plant adaptations to it) at finer spatial scales by creating positive feedbacks, which reverse relative productivity of ecosystems expected from abiotic conditions alone. Our results without herbivory indicate that one site has 26% less annual net primary production (ANPP) than the other site. With herbivory, the sites reverse in ANPP, so the site with lower ANPP without herbivory now is 15% greater than the site with higher ANPP wi...
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... Testing Their Predictions with Experimental Data on the Brine Shrimp Gary E. Belovsky, Chad Mellison, Chad Larson, and Peter A. Van Zandt ... models (models 1, 2, 7, and 8) didnot do well and generally overestimated persistence times,... more
... Testing Their Predictions with Experimental Data on the Brine Shrimp Gary E. Belovsky, Chad Mellison, Chad Larson, and Peter A. Van Zandt ... models (models 1, 2, 7, and 8) didnot do well and generally overestimated persistence times, which made them overly optimistic about ...
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Summary. Moose (Alces alces) and snowshoe hare (Lepus americanus) appear to compete with each other. This was determined using the " natural experiments " ofpopulations found in sympatry and allopatry on islands at Isle Royale... more
Summary. Moose (Alces alces) and snowshoe hare (Lepus americanus) appear to compete with each other. This was determined using the " natural experiments " ofpopulations found in sympatry and allopatry on islands at Isle Royale National Park, Michigan, and manipulated exclosures. The population densities from these areas are fit to a series of competition models based upon different competitive mech-anisms (Schoener 1974a), using non-linear egression tech-niques. A model of competition for food where the food can be separated into exclusively used and shared categories is found to predict observed ensities of moose and hare best. Finally, the competition model's parameters (fraction of food shared and competition coefficients) are shown to agree with values predicted independently from a foraging model.
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Summary. The summer (May-September) time budgets of 14 generalist herbivore species living in the same grassland environment are presented in terms of various component activities (e.g., walking, feeding, resting, etc.). All the species... more
Summary. The summer (May-September) time budgets of 14 generalist herbivore species living in the same grassland environment are presented in terms of various component activities (e.g., walking, feeding, resting, etc.). All the species exhibit a decrease in activity as average daily air tempera-ture increases. Greater body size and variety of habitats used by a species lead to increased time spent active. Use of a greater variety of habitats may increase activity time because different habitats provide suitable thermal condi-tions for activity at different imes of the day. Body size affects an herbivore's thermal balance through metabolism, body surface area and thermal inertia. The time spent feed-ing, exclusive of time spent searching for foods, is less for large than small herbivores. This may arise because large species must spend more time walking in the search for food to satisfy their energy requirements. The observed feeding time differences for species composing a com...
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Over the past 109 years, a Montana intermountain bunchgrass prairie annually became warmer (0.7°C) and drier (27%). The temperature and precipitation trends continued since 1978, as we studied nitrogen availability, annual aboveground... more
Over the past 109 years, a Montana intermountain bunchgrass prairie annually became warmer (0.7°C) and drier (27%). The temperature and precipitation trends continued since 1978, as we studied nitrogen availability, annual aboveground primary production (ANPP), plant phenology and species composition. Given the annual increase in temperature and decrease in precipitation, ANPP might be expected to decline; however, it increased by 110%, as the period of greatest production (late-May–June) became wetter and cooler, counter to the annual pattern, and this was strongest at lower elevations. Grass production increased by 251%, while dicot production declined by 65%, which increased grass relative abundance by 54%. Summer temperatures increased 12.5% which increased plant senescence by 119% and decreased fall plant regrowth by 68%. More intense summer senescence changed plant species composition in favor of more drought tolerant species. The greater ANPP and summer senescence may increas...
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Research Interests: Zoology, Ants, Transmission, Animals, Ant, and 3 moreBiological Pest Control, Grasshoppers, and Insect Vectors
Soundscape metrics were selected to monitor important Upper Great Lakes natural habitats to better understand the relationship and interaction between landscape structure and function, phenology and ecological processes. We will present... more
Soundscape metrics were selected to monitor important Upper Great Lakes natural habitats to better understand the relationship and interaction between landscape structure and function, phenology and ecological processes. We will present soundscape patterns and an analysis of the soundscape from six replicated habitats (three forest and three wetland types). One minute soundscape recordings were collected in eighteen sites at 30 minute intervals using automated sound recorders (SM2). Recordings from May to October (2012-2013) were uploaded each month to a digital acoustic library (www.real.msu.edu) where the recordings were stored and soundscape metrics computed. Over 400,000 soundscape recordings were collected and processed. Significant differences between habitats were observed based on the specific soundscape metrics used. For example, all habitats were significantly different from each other (n=25,409; F=594.5; Tukey p< 0.05) when comparing the Normalized Difference Soundscap...
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... The work was supported by a grant from the National Park Service to PA Jordan and DB Botkin, and grants to GE Belovsky from the Environmental Education Fund, the Richmond Society, Harvard University and the Society of Fellows. ...
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... The quantities of each food class in these diets appear in Table III, along with the observeddiet. ... (3) Barren cows have an observed diet which is identical with that for a cow with calf, even though both predicted diets deviate... more
... The quantities of each food class in these diets appear in Table III, along with the observeddiet. ... (3) Barren cows have an observed diet which is identical with that for a cow with calf, even though both predicted diets deviate substantially from the observed. ...
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ABSTRACT Studies of an optimal body size for individuals of different species based upon their foraging efficiency are reviewed and a detailed analysis of data specifically collected for this purpose is presented for Microtus... more
ABSTRACT Studies of an optimal body size for individuals of different species based upon their foraging efficiency are reviewed and a detailed analysis of data specifically collected for this purpose is presented for Microtus pennsylvanicus. The natural selection of body sizes for some species is shown to be consistent with their foraging efficiency. However, a general model of optimal body size based on foraging efficiency (Reiss, 1986), unlike the species by species approach presented here, is shown to be incorrect.