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Full-Text Articles in Life Sciences
Lidar Remote Sensing Variables Predict Breeding Habitat Of A Neotropical Migrant Bird, Scott J. Goetz, Daniel Steinberg, Matthew G. G. Betts, Richard T. Holmes
Lidar Remote Sensing Variables Predict Breeding Habitat Of A Neotropical Migrant Bird, Scott J. Goetz, Daniel Steinberg, Matthew G. G. Betts, Richard T. Holmes
Dartmouth Scholarship
A topic of recurring interest in ecological research is the degree to which vegetation structure influences the distribution and abundance of species. Here we test the applicability of remote sensing, particularly novel use of waveform lidar measurements, for quantifying the habitat heterogeneity of a contiguous northern hardwoods forest in the northeastern United States. We apply these results to predict the breeding habitat quality, an indicator of reproductive output of a well-studied Neotropical migrant songbird, the Black-throated Blue Warbler (Dendroica caerulescens). We found that using canopy vertical structure metrics provided unique information for models of habitat quality and spatial patterns of …
Predators And Life Histories Shape Lestes Damselfly Assemblages Along A Freshwater Habitat Gradient, Robby Stoks, Mark A. Mcpeek
Predators And Life Histories Shape Lestes Damselfly Assemblages Along A Freshwater Habitat Gradient, Robby Stoks, Mark A. Mcpeek
Dartmouth Scholarship
Survey data from New England showed that assemblages of Lestes damselflies are organized along the entire gradient of pond permanence and predator presence. One assemblage occupies vernal ponds lacking large dragonfly predators and fish; four are largely confined to temporary ponds that typically contain dragonfly predators; one dominates fishless permanent ponds and lakes where dragonflies are the top predators; and one dominates permanent ponds and lakes where fish are the top predators. We determined the role of life history and predation in maintaining this striking pattern by conducting a series of transplant experiments in the field and a laboratory experiment …
Nitrogen Budgets Of Phloem-Feeding Bark Beetles With And Without Symbiotic Fungi, Matthew P. Ayres, Richard T. Wilkens, Jonathan J. Ruel, María J. Lombardero, Erich Vallery
Nitrogen Budgets Of Phloem-Feeding Bark Beetles With And Without Symbiotic Fungi, Matthew P. Ayres, Richard T. Wilkens, Jonathan J. Ruel, María J. Lombardero, Erich Vallery
Dartmouth Scholarship
The nitrogen content of plant tissue is low relative to that of herbivores; as a consequence, dietary N can limit the growth and reproduction of herbivores and select for attributes that increase N acquisition. Bark beetles face a particularly severe challenge because the phloem that they consume is very low in nitrogen and phosphorus relative to their requirements. We quantified variation in the phloem concentrations of N and P in the host tree, Pinus taeda, and evaluated the following hypotheses regarding the role of symbiotic fungi in nutrient budgets of the herbivore Dendroctonus frontalis: D. frontalis experience variation …
The Consequences Of Changing The Top Predator In A Food Web: A Comparative Experimental Approach, Mark A. Mcpeek
The Consequences Of Changing The Top Predator In A Food Web: A Comparative Experimental Approach, Mark A. Mcpeek
Dartmouth Scholarship
Changing the top predator in a food web often results in dramatic changes in species composition at lower trophic levels; many species are extirpated and replaced by new species in the presence of the new top predator. These shifts in species composition also often result in substantial alterations in the strengths of species interactions. However, some species appear to be little affected by these changes that cause species turnover at other positions in the food web. An example of such a difference in species responses is apparent in the distributions of coenagrionid damselflies (Odonata: Zygoptera) among permanent water bodies with …
Selection Of Foraging And Nesting Sites By Black-Throated Blue Warblers: Their Relative Influence On Habitat Choice, Benjamin B. Steele
Selection Of Foraging And Nesting Sites By Black-Throated Blue Warblers: Their Relative Influence On Habitat Choice, Benjamin B. Steele
Dartmouth Scholarship
To understand why breeding Black-throated Blue Warblers (Dendroica caerulescens) select forests with dense shrubs, I assessed the value of this habitat in supplying opportunities for foraging and nesting. I predicted that these warblers would select shrub foliage for foraging if foraging substrate was important in their selection of habitat and that they would place their nests in areas of dense shrubs if nest-site availability affected habitat choice. To measure foraging and nest-site selection, I compared the proportion of foraging or nests in a particular habitat element to the availability of that element expressed as a proportion of all …
Behavioral Feeding Specialization In Pinaroloxias Inornata, The “Darwin's Finch” Of Cocos Island, Costa Rica, Tracey K. Werner, Thomas W. Sherry
Behavioral Feeding Specialization In Pinaroloxias Inornata, The “Darwin's Finch” Of Cocos Island, Costa Rica, Tracey K. Werner, Thomas W. Sherry
Dartmouth Scholarship
As a population, Cocos Finches exhibit a broad range of feeding behaviors spanning those of several families of birds on the mainland, while individuals feed as specialists year-round. Although this extreme intraspecific variability occurs as predicted in a tropical oceanic island environment, these specializations challenge contemporary ecological theory in that they are not attributable to individual differences in age, sex, gross morphology, or opportunistic exploitation of patchy resources. Instead, they appear to originate and be maintained behaviorally, possibly via observational learning. This phenomenon adds another direction to the evolutionary radiation of the Darwin's Finches and underscores the necessity for detailed …