Theoretically, sympatric species must partition resources or space to allow for coexistence. Determining empirically the specific resources each species exploits and species’ interactions (e.g., intra- and interspecific competition) can sometimes be challenging, thus the data are relatively sparse for certain taxa. This paucity of data exists for octopuses. Therefore, I chose to study niches of two sympatric octopuses (Octopus vulgaris and Macrotritopus defilippi) in an intracoastal habitat. Specifically, I assessed (1) spatial distribution of octopus home or “den” space, (2) habitat association, (3) octopus abundance, (4) foraging activity periods, (5) diet, and (6) associated substrates and behaviors used during foraging events. Octopus den locations were marked by GPS to quantify spatial patterns of both species and their spatial relationship to each other. Habitat associations were measured by quantifying photoquadrats of den and surrounding habitats. For foraging activity periods, a video camera was placed near an octopus den for 24-h observation to determine when each octopus species leaves/returns from foraging. Underwater video recording was used to determine associated foraging substrates and behaviors for both species. Prey remains from octopus’ dens and video recordings indicating prey consumption were used to determine diets of the two octopus species. Video recordings from the 24-h camera and foraging behavior events also provided observations of intra- and interspecific interactions. Results revealed that the two species are interspersed throughout the shallow Florida lagoon and are both abundant during the spring months (March, April, May). Although both species are interspersed throughout the lagoon, their den and surrounding habitat association differed. O. vulgaris was associated with hard bottom and M. defilippi was associated with soft bottom, thus they may not compete strongly for habitats. Each species used different foraging strategies and different primary prey, which may also lessen competition and facilitate coexistence. O. vulgaris had peak foraging activity during night hours, foraged mostly on hard bottom and mainly consumed bivalves while M. defilippi had peak foraging activity during day hours, foraged mostly on soft bottom and mainly consumed crustaceans. Octopuses also had species-specific foraging behaviors, with O. vulgaris using parachute attack and M. defilippi using flounder swimming and tripod stance. Additional intra- and interspecific interactions were video recorded and included: fishes following octopuses, predation attempts, agonistic encounters, cannibalism, and tactile communication. This study identified ecological and behavioral components that may facilitate coexistence of these sympatric species, provided insight into cephalopod niches and ecology, and provided baseline conservation requirements for sand-dwelling cephalopods, both of which may be using this site as a mating and nursery habitat. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2019. / FAU Electronic Theses and Dissertations Collection

Sexual, or behavioral, isolation is a form of reproductive isolation that impedes gene flow between divergent taxa. In this study, sexual isolation was measured in a sister-species pair of North American cactophilic fruitflies. The results show that interspecific behavioral isolation is dependent upon the strain of origin of D. mojavensis, but is independent of the strain of origin of D. arizonae. Interspecific sexual isolation is greatest in crosses involving D. mojavensis from sympatry, which is consistent with reinforcement, and seems to be attributable to increased reluctance by D. mojavensis females and D. arizonae males to mate with heterospecifics. Contrary to previous studies, I found strong evidence for reproductive isolation between two strains of D. arizonae. The majority of the observed behavioral isolation seems to be the result of intraspecific, interpopulation encounters between females from Southeastern Mexico and males derived from the Northern population.

This research represents the first multi-year investigation of the feeding ecology of Gombe’s Cercopithecus populations. The main goal of this study was to identify dietary overlap and distinctiveness among the phenotypes in our study group, a mixed species group of guenons comprised of C. ascanius, C. mitis, and C. ascanius x C. mitis hybrids. Field assistants collected feeding data using ad libitum observations as well as instantaneous scan sampling at 30-minute intervals from July 2014 to December 2018. A total of 63 plant species were identified in our group’s diet. Results indicate that a significant difference exists between the diets of each phenotype. The results also found an unusually high percentage of invertebrate eating (54%) in our group. These findings suggest that invertebrates are an important food resource for the Gombe study group and may help facilitate coexistence in an environment where there are many sympatric primate species. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2019. / FAU Electronic Theses and Dissertations Collection

Submitted by Jos? Henrique Henrique (jose.neves@ufvjm.edu.br) on 2018-07-04T19:40:19Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) paula_cristina_barros_andrade.pdf: 4804696 bytes, checksum: 4747b9532db16586177823f2a1eb0977 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2018-07-18T13:01:12Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) paula_cristina_barros_andrade.pdf: 4804696 bytes, checksum: 4747b9532db16586177823f2a1eb0977 (MD5) / Made available in DSpace on 2018-07-18T13:01:12Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) paula_cristina_barros_andrade.pdf: 4804696 bytes, checksum: 4747b9532db16586177823f2a1eb0977 (MD5) Previous issue date: 2017 / Funda??o de Amparo ? Pesquisa do estado de Minas Gerais (FAPEMIG) / Investigar as rela??es ecol?gicas entre esp?cies simp?tricas e suas intera??es com o habitat, s?o importantes para a compreens?o dos mecanismos que controlam a estrutura da comunidade ecol?gica. Entretanto, informa??es a respeito dos mecanismos que permitam a coexist?ncia entre mam?feros simp?tricos s?o ainda escassas. Descrevemos no presente estudo, os padr?es de dieta dos carn?voros simp?tricos Chironectes minimus e Lontra longicaudis, analisamos os poss?veis mecanismos de particionamento de recursos entre essas esp?cies, a partir das dimens?es de nicho alimentar, temporal e espacial e discutimos o potencial para intera??es interespec?ficas, como a competi??o e preda??o. Os h?bitos alimentares dos carn?voros foram estudados a partir das an?lises de amostras de fezes coletadas entre novembro de 2008 e fevereiro de 2012, em fragmentos de Mata Atl?ntica no arroio Morungava, localizado no munic?pio de Gravata?, Rio Grande do Sul, Brasil. Foram coletadas 85 amostras de C. minimus e 21 amostras de Lontra longicaudis, distribu?das entre 23 latrinas encontradas ao longo das margens direita e esquerda do arroio. A cu?ca d??gua e a lontra neotropical apresentaram h?bitos alimentares especialistas, por?m, com dietas distintas, especialmente com rela??o as preferencias alimentares e ? frequ?ncia dos itens consumidos, o que provavelmente se reflete no baixo ?ndice de sobreposi??o de nicho tr?fico entre as esp?cies. Chironectes minimus apresentou uma dieta primordialmente carnivora, no entanto, bastante diversificada, consumindo principalmente crust?ceos dec?podos (100%), insetos (69%) e peixes (40%), enquanto L. longicaudis apresentou uma dieta baseada principalmente no consumo de peixes (95%), seguidos por insetos (71%), e anf?bios anuros (67%). Observamos um padr?o de segrega??o espacial e temporal entre a cu?ca d??gua e a lontra neotropical na ?rea de estudo, embora, evid?ncias demonstrem que essas esp?cies coexistem em algum momento, tanto no espa?o quanto no tempo, j? que, registramos a preda??o da cu?ca d??gua pela lontra neotropical. Este ? o primeiro estudo de particionamento de recursos entre C. minimus e L. longicaudis, fornecendo informa??es importantes sobre os h?bitos alimentares destes mam?feros semiaqu?ticos e sobre os mecanismos ecol?gicos respons?veis pela estrutura desta guilda de carn?voros na Mata Atl?ntica. / Disserta??o (Mestrado) ? Programa de P?s-gradua??o em Biologia Animal, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2017. / Investigate the ecological relationships between sympatric species and their interactions with the habitat are important for understanding the mechanisms that control the structure of ecological communities. However, informations regarding the mechanisms that allow the coexistence among sympatric mammals are still scarce. Here we described the feeding habits of two sympatric carnivores, Chironectes minimus and Lontra longicaudis, analyzed the resource partitioning mechanisms investigating different niche dimensions such as feeding, spatial and temporal niches, and also discussed the potential for interspecific interactions, such as intrespecific competition and predation. The feeding habits were studied from the analysis of fecal samples collected between November 2008 and February 2012, in fragments of Atlantic Forest in the Morungava stream, located in the city of Gravata?, Rio Grande do Sul, Brazil. 85 samples of C. minimus and 21 samples of Lontra longicaudis distributed among 23 latrines found along the right and left banks of the stream were collected, Water opossum and Neotropical otter presented specialized food habits, however, with different diets, especially regarding food preferences and frequency of consumed items, which is probably reflected by the slight trophic niche overlap between species. Chironectes minimus presented a primordial carnivorous diet, however, very diversified, consuming decapod crustaceans (100%), insects (69%) and fishes (40%), while L. longicaudis presented a diet based mainly on fish consumption 95%), followed by insects (71%), and anuran amphibians (67%). We observed a spatial and temporal segregation pattern among the water opossum and the Neotropical otter in the study site, although, evidences show that these species coexist at some time, both in space and time, since we recorded the predation of the water opossum by the Neotropical otter. This is the first study of resource partitioning among C. minimus and L. longicaudis, providing significant information about the feeding habits of these semi-aquatic mammals and about the ecological mechanisms responsible for the structure of this carnivorous guild in Atlantic Forest.

Submitted by FABIANA DA SILVA FRANÇA (fabiana21franca@gmail.com) on 2017-12-07T14:56:55Z No. of bitstreams: 1 ArquivoTotal.pdf: 2620143 bytes, checksum: c51d9011e9a0d81c6c8cb5241c91e599 (MD5) / Made available in DSpace on 2017-12-07T14:56:55Z (GMT). No. of bitstreams: 1 ArquivoTotal.pdf: 2620143 bytes, checksum: c51d9011e9a0d81c6c8cb5241c91e599 (MD5) Previous issue date: 2015-06-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Biogeographic studies try to understand the distribution patterns of the biologic groups, considering historic and biologic factors. At Brazil’s Northwest, there are few studies in this sphere. In this area, there are three species of hummingbirds: A. leucogaster, A. versicolor and A. fimbriata, wich have a genetic proximity – belong to the same gender – and are sympatric, and because of that can turn out to be potential competitors and don’t co-occur. But in case they do co-occur, they can be syntopic due to a divergence in some niche dimension. In order to comprehend wich historic and ecologic factors mold the distribution of these species, we reviewed the occurrences of the three of them, analized potencial distribution based on the niche aspects and revised the phylogenies of the group. Therefore, we used QGis 2.9, R 3.0.1 (Maxent), bioclimatic variables of the WorldClim, Statistic 7.0 (ANOVA one way) and the recently published phylogenies. We’ve registered 232 points of occurrence, (94%) of the points are associated to forest areas, and only 15 (6%) occurred in open environments. The co-occurrence between A. leucogaster and A. fimbriata can be easily explained by the phylogenetic distance and by the niche divergence, once they were the species with the most different data when observed by these factors. There is no sympatry of A. leucogaster and A. versicolor. The performances of the models and test of the ANOVA indicate that A. fimbriata and A. versicolor show themselves more similar in the fundamental niche, while the A. leucogaster niche is influenced in a differentiated way by the variables. A. leucogaster, the most recent of the three, has the history of lineage linked to environments of the Quaternário, related to the coastal forests. A. versicolor have a history based on the expansion of humid forests of the Mioceno Superior and Plioceno. When it comes to the A. fimbriata, it has a history that goes from the Mioceno Superior to the Pleistoceno Médio, also related to the expansion of the forests. Because Amazilia is not a monophyletic group and A. fimbriata presents ecologic and historic data that represent an evolutive divergence, we sugest a different taxonomic representation, at the gender level, to this species. / Estudos biogeográficos buscam compreender os padrões de distribuição dos grupos biológicos, levando em consideração fatores históricos e ecológicos. No nordeste oriental do Brasil, poucos são os estudos realizados nesse âmbito. Nessa região ocorrem três espécies de beija-flores, A. leucogaster, A. versicolor e A. fimbriata, que, por possuírem proximidade filogenética -pertencerem ao mesmo gênero -, e serem simpatricas, podem ser potenciais competidoras e não co-ocorrerem. Mas, caso co-ocorram, podem ser sintópicas, devido à divergência em alguma dimensão de nicho. No intuito de compreender que fatores históricos e ecológicos moldam a distribuição dessas espécies, revisamos as ocorrências das três espécies, analisamos distribuição potencial com base em aspectos do nicho e revisamos as filogenias do grupo. Para tal, utilizamos QGis 2.9, R 3.0.1 (Maxent), variáveis bioclimáticas do WorldClim, Statistic 7.0 (ANOVA one way) e as filogenias recentemente publicadas. Registramos 232 pontos de ocorrência, (94%) dos pontos estão associados a áreas florestais, e apenas 15 (6%) ocorreram em ambientes abertos. A co-ocorrência entre A. leucogaster e A. fimbriata pode ser facilmente explicada tanto pela distância filogenética como pela divergência de nicho, visto que foram as espécies com dados mais distintos, quando observados esses fatores. Não existe simpatria de A. leucogaster e A. versicolor. As performances dos modelos e teste o ANOVA indicam que A. fimbriata e A. versicolor mostram-se mais similares no nicho fundamental, enquanto o nicho de A. leucogaster é influenciado de forma diferenciada pelas variáveis. A. leucogaster, a mais recente dentre as três, tem a história da linhagem ligada a ambientes do Quaternário, relacionadas às florestas costeiras. A. versicolor possuem história baseada na expansão de matas úmidas do Mioceno Superior e Plioceno. Já A. fimbriata possui uma história que vai desde o Mioceno Superior até o Pleistoceno Médio, também relacionada à expansão das florestas. Tanto por Amazilia não ser um grupo monofilético quanto por A. fimbriata apresentar dados ecológicos e históricos que representam uma divergência evolutiva, sugerimos uma representação taxonômica distinta, a nível de gênero, para essa espécie.

Intercropping switchgrass (Panicum virgatum) between tree rows within young pine (Pinus spp.) plantations is a novel method to generate lignocellulosic biofuel feedstocks within intensively managed forests. Intensively managed pine supports diverse avian assemblages potentially affected by establishment and maintenance of a biomass feedstock. I sought to understand how establishing switchgrass on an operational scale affects bird communities within intercropped plantations as compared to typical intensively managed loblolly pine (Pinus taeda) plantations. I conducted breeding bird point counts, nest searching and monitoring, and coarse woody debris (CWD) surveys following establishment of intercropped switchgrass stands (6 replicates), traditionally-managed pine plantations, and switchgrass-only plots (0.1 km2 minimum) in Kemper Co., MS from 2011 to 2013. I found establishment of intercropping did not affect downed CWD, but reduced standing snags and green trees. I detected 59 breeding bird species from 11,195 detections and modeled nest survivorship for 17 species. Neotropical migrants and forest-edge associated species were less abundant in intercropped plots than controls for two years after establishment, and more abundant in year three. Short distance migrants and residents were scarce in intercropped and control plots initially, and did not differ between these treatments in any year. Species associated with pine-grass habitat structure were less abundant initially in intercropped plots, but converged with pine controls in subsequent years. Switchgrass monocultures provided minimal resources for birds. There was no evidence supporting an effect of intercropping on songbird nest survivorship. I found evidence for dominance of one species, yellow-breasted chat (Icteria virens), over another, indigo bunting (Passerina cyanea) in competition for nest sites, which illustrates how songbirds competing for nest sites can coexist in sympatry without the dominant species driving subordinate competitors to local extirpation. This dissertation, and related publications, are among the earliest research on wildlife response to intercropping. Forest managers implementing intercropping within pine plantations where vertebrate conservation is a management priority should be aware of potential changes to snag-utilizing species from reductions in green trees and snags. Songbird populations may lag behind traditional management for up to two years following establishment of switchgrass. Intercropping neither positively nor negatively affected songbird nest survival.

Understanding why some species coexist and others do not remains one of the fundamental challenges of ecology. While several lines of evidence suggest that closely related species are unlikely to occupy the same habitat because of competitive exclusion, there are many cases where closely related species do co-occur. Research comparing sympatric and allopatric populations of co-occurring species provides a framework to understand the role of phenotypic diversification in species coexistence. In this study I focus on the livebearing fish Poeciliopsis baenschi and ask if differences in phenotypic traits among populations can be explained by the presence or absence of the congeneric species P. turneri. I focus on phenotypic divergence in life history traits and in body shape, two sets of integrated traits likely to respond to variation in competition. Additionally, I compare explore the effects of sympatry and allopatry on sexual dimorphism. I take advantage of a natural experiment in western Mexico where P. baenschi co-occur with P. turneri in some locations (sympatric populations) but also exist in isolation in other locations (allopatric populations). My results show that sympatric populations of P. baenschi differed significantly in life history traits and body shape when compared to their allopatric counterparts. Additionally, the amount of sexual dimorphism differed between sympatric and allopatric populations of P. baenschi, suggesting different constraints might exist in sympatry and allopatry for sexual dimorphism. Lastly, I explore my results in the context of trait evolution as it relates to species coexistence.

No description available.

Intensive cytotype screening in the primary contact zone of relict serpentine Knautia arvensis agg. revealed a striking predominance of the derivative tetraploid (81 % of subpopulations) over the diploid maternal race. Eleven mixed-ploidy subpopulations with the close spatial proximity of both cytotypes were identified. Flow cytometric analyses of almost 5 000 individuals led to discovery of two extremely rare minority cytotypes (3x, 6x). Vegetation analyses were made at two different spatial scales and in both cases confirmed the absence of distinctions in habitat preferences of cytotypes. Slight microhabitat segregation of cytotypes was however apparent at the finest spatial scales. Cytotype distribution within mixed-ploidy sites was not random. Striking patterns of cytotype clumping into cytotype uniform patches and negative spatial correlations between diploid and tetraploid individuals were apparent at all sites. Distribution of life cycle stages of diploids and tetraploids within the mixed-ploidy subpopulations were significantly different. The clonality was the most common mode of reproduction in the subpopulations of both cytotypes. Seedlings accounted for only 7 % of new plants. Significant distinctions in the plant vigour between the cytotypes were showed during the in situ comparison in...

Several hypotheses from community ecology were tested using habitat and diet patterns for six catostomid fishes of the Assiniboine River, Manitoba. Specifically, I examined expected assemblage patterns based on the equilibrium-nonequilibrium continuum that are based on competition as a structuring mechanism. The catostomid assemblage showed characteristics of both equilibrium and nonequilibrium assemblages. Habitat utilization was not proportional to habitat availability for depth, velocity, and substrate indicating habitat selection occurs. These patterns are influenced by the distributions of soft Lake Agassiz deposits and harder glacial till-plain habitats and therefore localized. Species co-occurred in relation to abundance indicating negative associations assumed in competition-based theory were not apparent. In addition, species from the same subfamily co-occurred more often than expected by chance, indicating positive within-group comparisons, except for silver redhorse, which did not co-occur differently than random. Species from the same feeding group co-occur most frequently with conspecifics, indicating species have specific habitat patterns. Benthic invertebrate distributions and fish distributions were positively correlated with fish diet. Within-feeding-group comparisons indicated species that co-occurred frequently consumed the same food items, but showed subtle differences in abundance of diet items. The most common diet items varied among white sucker, silver redhorse, golden redhorse, and shorthead redhorse, indicating that, although these species co-occur, subtle differences in feeding behavior may account for differences in relative abundance and frequency of diet items. Quillback and bigmouth buffalo shared a few core food items, but co-occurred infrequently. Inter-specific interactions showed silver redhorse diets were a subset of white sucker diets, white sucker diets were a subset of golden redhorse diets, shorthead redhorse diets were a subset of silver redhorse and golden redhorse diets, while bigmouth buffalo diets were a subset of quillback diets. Lower richness and prevalence of organisms in quillback and bigmouth buffalo diets were due to highly aggregated prey items. Benthic invertebrate distributions were aggregated and dependent on the predictable patterns of substrates, based on hydraulic sorting in the meandering along the river. Large-scale redundancy of species-habitat associations was correlated with historical (phylogenetic) or adaptive (morphological) constraints on habitat selection. Stream habitats are constrained by regional factors of slope and sediments, but also determined by stable, repetitive and predictable local processes of erosion, transport, and deposition (meandering). The fish-habitat associations of catostomids in the Assiniboine River provide an example of interaction between the abundance of the component species, the phylogenetic constraints on the niche, and the deterministic nature of the spatial distribution of habitats. Within-feeding-group pairs showed that local habitat overlap is positively correlated with geographic overlap, while local diet overlap is negatively correlated with geographic overlap. Two species pairs (silver redhorse and golden redhorse and bigmouth buffalo and quillback) were concluded to have symmetric overlaps at the geographic scale and stable interactions. Using the functional niche concept ecological theory provides a link between ecology and biogeography of sympatric species. The multi-analytical approaches in this study provide insights into the structuring of north temperate prairie river fish communities, through hypothesis testing and correlation that have application beyond Prairie Rivers. / October 2005