Life Sciences Commons^™

A Mechanistic Examination Of Interspecific Competition Between Wild And Domestic Herbivores, Courtney Check

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Large herbivores, such as mule deer and cattle have similar life histories and likely compete for resources. However, quantifying the extent to which these species compete and the specific resources they compete for has proved challenging. My research examines if cattle influence deer abundance and behavior due to competition for forage, competition for shade, and/or by affecting the predation risk of deer. Using a grid of autonomous trail cameras, I was able to determine if cattle abundance influences local deer abundance in relation to specific resources and habitat features. Using GPS data from collared deer, I was also able to …

A Test Of Food Partitioning Between The Aquatic Larvae Of Two Parapatric Species Of Two-Lined Salamander (Eurycea Bislineata Species Complex) In A Zone Of Sympatric Contact, Carlos D. Camp, S. Michael Owensby, Emily Benfield, Jessica A. Wooten

Georgia Journal of Science

Phylogenetically related species with similar ecologies often partition resources when in sympatry. Food is an important factor in the co-occurrence of sympatric salamanders, and food partitioning occurs in a variety of sympatric, similar species. Several members of the Two-lined Salamander (Eurycea bislineata) species complex are largely parapatric but co-exist within a narrow zone of sympatric contact. Because larvae of these salamanders frequently occur in very high densities, we tested the hypothesis that larvae of the Blue Ridge Salamander (E. wilderae) and the Southern Two-lined Salamander (E. cirrigera) partition food in sympatry in northeastern Georgia. …

The Effects Of Interspecific Competition And Predation On Survival Of Neonate Mule Deer, Daniel W. Sallee

Theses and Dissertations

Mule deer (Odocoileus hemionus) populations are influenced by multiple factors, including interspecific competition and predation. Interspecific competition can affect resource acquisition and survival through altering space use and access to preferred habitat. Mule deer in some areas alter space use in the presence of competing species, including bison (Bison bison), cattle (Box taurus), elk (Cervus canadensis), and feral horses (Equus caballus), however the influence of competition on survival of mule deer during specific life history stages, such as birthing and rearing of neonates, is largely unknown. In addition to competition, predation can influence mule deer populations and even limit population …

Character Displacement In The Midst Of Substantial Background Evolution In Anolis Lizard Island Populations, Ambika Kamath, Nicholas C. Herrmann, Kiyoko M. Gotanda, Kum C. Shim, Jacob Lafond, Gannon Cottone, Heather Falkner, Todd S. Campbell, Yoel E. Stuart

Biology: Faculty Publications and Other Works

Negative interactions between species can generate divergent selection that causes character displacement. However, other processes cause similar divergence. We use spatial and temporal replication across island populations of Anolis lizards to assess the importance of negative interactions in driving trait shifts. Previous work showed that the establishment of Anolis sagrei on islands drove resident Anolis carolinensis to perch higher and evolve larger toepads. To further test the interaction's causality and predictability, we resurveyed a subset of islands nine years later. Anolis sagrei had established on one island between surveys. We found that A. carolinensis on this island now perch higher …

Impact Of Increased Green Turtle Nesting On Loggerhead Fitness, Amanda R. Carmichael

Honors Undergraduate Theses

Marine turtles exhibit strong fidelity to their nesting beaches, making the conservation of nesting beaches important for ensuring successful sea turtle populations. Conservation of these nesting beaches involves understanding how species interact with the environment and each other, and understanding how environmental change and population growth can affect the suitability of the nesting habitat. The Archie Carr National Wildlife Refuge (ACNWR) is unusual in its high density of sea turtle nesting by two species: green (Chelonia mydas) and loggerhead (Caretta caretta) turtles. The ACNWR in Melbourne Beach, Florida was established in 1991 due to the high density of loggerhead nesting, …

Competition And Community Interactions Of Two Generalist Herbivores, Elizabeth Ellen Barnes

Electronic Theses and Dissertations

Competition can have far-reaching consequences for the fitness and distribution of many organisms. In herbivorous insects, competition mediated by a third organism is more common than direct competition and has a strong effect on insect communities; yet most research on indirect competition among herbivores focuses on dietary specialists, and those studies that do include generalists tend to rear them on agricultural crops. My project examines species interactions at three levels: intraspecific competition (within species), interspecific competition (between species), and ecosystem engineering effects at the community level. I studied competition and community interactions of two temporally-separated species of herbivorous insects, western …

Safaa Ahmed Hamdan Alghasyah Aldhanhani, Safaa Ahmed Hamdan Alghasyah Aldhanhani

Theses

Sudan grass (Sorghum x drummondii) is commonly grown for the production of animal fodder in the UAE. Cyperus conglomeratus (locally termed 'Thenda') is a sedge native to the UAE, and one of the very few plants that colonize soils of shifting desert dunes. The native plant is grazed by camels, and may thus have a potential for animal feed production. While Sudan grass is a mycotrophic plant that normally lives in symbiosis with arbuscular mycorrhizal fungi for facilitation of nutrient uptake, C. conglomeratus is a non-host to these root symbionts. In the deseli sedges rhizosheaths comprising of dense …

Comparative Study Of Nutrient Uptake Between Sorghum X Drummond Ii And Cyperus Conglomeratus, A Desert Sedge Native To The Uae, Safaa Alm1ed Alghasyah Aldhanhani

Theses

Sudan grass (Sorghum x drummondii) is commonly grown for the production of animal fodder in the UAE. Cyperus conglomeratus (locally termed ‘Thenda’) is a sedge native to the UAE, and one of the very few plants that colonize soils of shifting desert dunes. The native plant is grazed by camels, and may thus have a potential for animal feed production. While Sudan grass is a mycotrophic plant that normally lives in symbiosis with arbuscular mycorrhizal fungi for facilitation of nutrient uptake, C. conglomeratus is a non-host to these root symbionts. In the desert sedges rhizosheaths comprising of dense coats of …

Super-Killers: Environmental Isolates That Antagonize Pathogenic Vibrio, Abigail Joy

Honors Projects

Vibrio are members of a bacterial group that thrive in diverse aquatic environments including on the surface of aquatic animals, free-living in the water column, and in association with suspended particles. The total Vibrio counts in the coastal ocean ranges from 10³-10⁵ per milliliter of water depending on seasons and water temperature. Although many different species of Vibrio persist in the water column, pathogenic strains, such as Vibrio cholerae and Vibrio parahaemolyticus are absent or rare in marine environments. We hypothesize that the low abundance of these pathogenic species may be due to interspecific competition among environmental …

Restoration Of Native Biodiversity In Altered Environments: Reintroduction Of Atlantic Salmon Into Lake Ontario, Aimee Lee S. Houde

Electronic Thesis and Dissertation Repository

Less than a quarter of reintroduction programs have succeeded in re-establishing a self-sustaining population of an extirpated species. Optimal source population selection, based on an evolutionary perspective, could increase the fitness of translocated individuals, thereby improving the success rate of restoring extirpated populations. Here, using three source populations of Atlantic salmon, Salmo salar (LaHave River, Sebago Lake, and Lac Saint-Jean), that are being used for reintroduction efforts into Lake Ontario, I examined two optimal source population selection approaches: environment matching and adaptive potential. For environment matching, source populations from locations containing similar key environment features as the reintroduction location should …

Positive Relationships Between Association Strength And Phenotypic Similarity Characterize The Assembly Of Mixed-Species Bird Flocks Worldwide, Hari Sridhar, Umesh Srinivasan, Robert A. Askins, Julio Cesar Canales-Delgadillo, Chao-Chieh Chen, David N. Ewert, George A. Gale, Eben Goodale, Wendy K. Gram, Patrick J. Hart, Keith A. Hobson, Richard L. Hutto, Sarath W. Kotagama, Jessie L. Knowlton, Tien Ming Lee, Charles A. Munn, Somchai Nimnuan, B. Z. Nizam, Guillaume Péron, V. V. Robin, Amanda D. Rodewald, Paul G. Rodewald, Robert L. Thomson, Pranav Trivedi, Steven L. Van Wilgenburg, Kartik Shanker

Biology Faculty Publications

Competition theory predicts that local communities should consist of species that are more dissimilar than expected by chance. We find a strikingly different pattern in a multicontinent data set (55 presence-absence matrices from 24 locations) on the composition of mixed-species bird flocks, which are important sub-units of local bird communities the world over. By using null models and randomization tests followed by meta-analysis, we find the association strengths of species in flocks to be strongly related to similarity in body size and foraging behavior and higher for congeneric compared with noncongeneric species pairs. Given the local spatial scales of our …

From Energy Gradient And Natural Selection To Biodiversity And Stability Of Ecosystems, Bo Deng

Department of Mathematics: Faculty Publications

The purpose of this paper is to incorporate well-established ecological principles into a foodweb model consisting of four trophic levels --- abiotic resources, plants, herbivores, and carnivores. The underlining principles include Kimura's neutral theory of genetic evolution, Liebig's Law of the Minimum for plant growth, Holling's functionals for herbivore foraging and carnivore predation, the One-Life Rule for all organisms, and Lotka-Volterra's model for intraand interspecific competitions. Numerical simulations of the model led to the following statistical findings: (a) particular foodwebs can give contradicting observations on biodiversity and productivity, in particular, all known functional forms -- - positive, negative, sigmoidal, and …

Ecological Determinants Of Survival And Reproduction In The Spotted Hyena, Heather E. Watts

Biology Faculty Works

Large carnivores play a key role in the structuring and dynamics of many ecosystems, yet the factors influencing dynamics of carnivore populations themselves are often poorly understood. Spotted hyenas (Crocuta crocuta) are the most abundant large carnivores in many African ecosystems. We describe demographic patterns in a population of spotted hyenas observed continuously for 15.5 years, and assess the effects of per capita prey availability, interspecific competition, rainfall, anthropogenic disturbance, and disease on 2 key determinants of population dynamics: reproduction and survival. Annual reproduction, survival of juveniles (i.e., recruitment to adulthood), and mortality of adults varied among years of the …

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 …

Feeding-Induced Changes In Plant Quality Mediate Interspecific Competition Between Sap-Feeding Herbivores, Merrill A. Peterson

Biology Faculty and Staff Publications

Feeding-induced plant resistance is a well-documented phenomenon for leaf-chewing insects. Furthermore, feeding-induced resistance provides the mechanistic basis for many cases of delayed interspecific competition, whereby previous feeding by one species diminishes the performance of other herbivores which attack the same plant later in the season. This phenomenon, however, has been very poorly investigated for sap-feeding insects. The results we present here for salt marsh-inhabiting planthoppers (Prokelisia dolus and P. marginata) provide one of the few known examples of delayed, plant-mediated interspecific competition between two sap-feeding insects.

Three lines of experimental evidence from the laboratory, field cages, and open …

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 …

Intraspecific And Diffuse Competition: The Response Of Nassella Pulchra In A California Grassland, Andrew R. Dyer, Kevin J. Rice

Faculty Publications

In inland California grasslands, the high densities of alien annual species have altered the growing environment for native perennial grasses. Using variable-density plots, we measured the influence of intraspecific competition (conspecifics only) and diffuse competition (mixed-composition neighborhoods that include conspecifics) on growth and survival of Nassella pulchra, purple needlegrass. We assessed the effects of intraspecific and diffuse competition in weeded plots and unweeded plots, respectively, across a density gradient of N. pulchra plants (16–356 plants/m2). We used summer fire and spring sheep grazing to reduce diffuse competition in unweeded plots. The potential effect of rooting volume on competitive interactions …

Comparison Of Dietary Overlap Between Allopatric And Sympatric Geckos, Paul D. Klawinski, R. Kathryn Vaughan, Daniel Saenz, William Godwin

Faculty Publications

Two gecko species, Hemidactylus turcicus and Cyrtopodion scabrum, have been introduced into the Port of Galveston, Texas. While H. turcicus has been established for a longer period of time, the relatively recent introduction of C. scabrum near the entrance of the Port has apparently led to the displacement of H. turcicus in that area. This has resulted in a distribution in which the two populations’ are largely allopatric except for a narrow band of sympatry at the periphery of each of their ranges. We examined stomach contents of both species in allopatry and sympatry in order to determine if …

The Species-Genus Relationship In Antillean Bat Communities, Donald A. Mcfarlane

WM Keck Science Faculty Papers

The ratio of the number of species to the number of genera in an island community has long been recognised as a potential proxy indicator of competitive interaction. An analysis of this relationship in the bat fauna of the Antillean archipelago demonstrates that the observed species-genus ratios are significantly depressed below null-model expectations, and that the magnitude of this depression is inversely proportional to the log of the appropriate island area. These observations are consistent with the hypothesis that interspecific competition may play an important role in structuring Antillean bat communities.