Thesis (Ph. D.)--Auburn University, 2009. / Abstract. Vita. Includes bibliographical references.

Biological invasions represent both an urgent conservation problem and an opportunity to advance ecological theory. Development of pertinent research questions and proactive management strategies require knowledge of which introduced species are present and of spatiotemporal trends in the distribution of natives and invaders. In Chapter 2 we developed a quantitative framework to identify spreaders and decliners and estimate invasion chronologies based on a historical fish presence data set for upper and middle New River (UMNR) tributaries. Our framework accounts for spatiotemporal variability in sampling effort by aggregating presences by watershed and expressing range size as a function of the number of watersheds sampled per time period. The majority (55%) of fish species present in the study area were introduced, 51% of which were spreaders. Most spreaders (84%) appeared to be spreading exponentially. The rate of new introductions detected in the study area has slowed since the mid-20th century. Two natives, the mound-spawning bluehead chub Nocomis leptocephalus and its strong nest associate (reproductive mutualist), mountain redbelly dace Chrosomus oreas, were among the most rapid spreaders. Four natives showed evidence of decline. Our framework leverages historical presence data to reconstruct temporal trends in species distributions. It sets the stage for further study of factors driving stream fish invasions and declines in the Appalachian region, and is transferable to diverse taxonomic groups and geographic regions. Species traits and human activities mediating stream-fish invasions remain poorly understood. In Chapter 3 we modeled the contribution of species traits to invasion success of UMNR tributary fishes during the colonization and spread stages. Biological traits accurately explained colonization and spread success, whereas ecological traits resulted in less accurate models. Colonization success was positively related to time since introduction, benthic feeding, an equilibrium life history, and nest spawning. Successful spread was positively related to winter air temperature in the native range and an equilibrium life history. Variables estimating human use and propagule pressure were non-informative. Traits that influenced invasion success were consistent with the hypothesis that human land-use practices have increased the invasibility of highland watersheds by creating novel conditions suited to lowland and equilibrium invaders. / Master of Science

The introduction of trout has been implicated in the declines in native fish fauna in New Zealand and worldwide. Since the introduction of brown (Salmo trutta) and rainbow (Oncorhynchus mykiss) trout to New Zealand in 1867, their distribution has spread and they have been implicated in the fragmentation of native fish distributions, particularly native non-migratory galaxiids. However, in the Upper Waimakariri basin the co-occurrence of trout and galaxiid populations is relatively common, even in streams where trout reach sizes known to be piscivorous. To investigate mechanisms that may regulate trout and galaxiid co-occurrence, I investigated differences in antipredator behaviour and growth rate between stream types with varying levels of trout presence. Using quantitative survey data collected between 1997 and 2006, I found that trout abundance was low and varied annually in frequently disturbed sites compared their high abundance in stable streams. This finding was used to classify streams into three population types, barrier (trout absent), disturbed (trout presence intermittent) and sympatric (constant trout presence). Using this classification, I tested the effects of trout chemical cues on galaxiid activity and refuge use in artificial channels. There were no differences in activity or refuge use between trout odour and there were no effects of population type or galaxiid size during both the day and the night. Using otolith weight-fish length relationships in galaxiids collected from each population type, I found that galaxiid growth rate was higher in disturbed streams than in stable streams either with or without trout. An experiment manipulating trout size and presence, over two months in a natural stream, found galaxiids from treatments without trout grew slower than those with trout. Slow growth rates in galaxiids above trout-migration barriers and in sympatry, combined with low growth rates in treatments without trout suggest that the mechanisms that regulate galaxiid growth are more complex than previously thought.

Nonnative species are reshaping global ecosystems. The success of a nonnative species hinges on both biological and cultural variables. Primates represent a minority of nonnative species but warrant research to understand ecological implications and management solutions. The Florida Fish and Wildlife Conservation Commission recognizes three species of nonnative primates in Florida that include populations of rhesus macaques (Macaca mulatta) in Marion County, squirrel monkeys (Saimiri spp.) in Broward County, and green monkeys (Chlorocebus sabaeus) in Broward County. This study focused on the Dania Beach C. sabaeus population. The goals of this study were to: 1) determine the geographical origins and species of the monkeys, 2) record demographics and determine population growth rate, 3) assess the public’s perception of monkeys, and 4) understand the influence of human provisioning on the population’s behavior and biology. Public surveys and direct field observations of social groups provided baseline data to show that unlike other introduced primates (e.g., macaques in Marion County and green monkeys in the Caribbean), the Dania Beach monkey population has strong public support and is at risk of extinction within the next 100 years. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2019. / FAU Electronic Theses and Dissertations Collection

This research investigates land use change and the area of occurrence of an introduced primate species, Chlorocebus sabaeus, from 1940 until the present. Research into the importation and subsequent release of these monkeys has revealed that they were released from a failed tourist attraction in 1947. The attraction was located southeast of the Hollywood International Airport in Fort Lauderdale, Florida. Remote sensing techniques were utilized to examine land use change over time, create a land classification map, and create a canopy model. These data were used to better understand the area of occurrence of an introduced primate species by examining anthropogenic changes through time and measuring changes in available forest habitat. Corridors, and their transformation through the decades, were evaluated to better understand potential dispersal routes and connectivity to natural areas for colonization. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2019. / FAU Electronic Theses and Dissertations Collection

The introduction of trout has been implicated in the declines in native fish fauna in New Zealand and worldwide. Since the introduction of brown (Salmo trutta) and rainbow (Oncorhynchus mykiss) trout to New Zealand in 1867, their distribution has spread and they have been implicated in the fragmentation of native fish distributions, particularly native non-migratory galaxiids. However, in the Upper Waimakariri basin the co-occurrence of trout and galaxiid populations is relatively common, even in streams where trout reach sizes known to be piscivorous. To investigate mechanisms that may regulate trout and galaxiid co-occurrence, I investigated differences in antipredator behaviour and growth rate between stream types with varying levels of trout presence. Using quantitative survey data collected between 1997 and 2006, I found that trout abundance was low and varied annually in frequently disturbed sites compared their high abundance in stable streams. This finding was used to classify streams into three population types, barrier (trout absent), disturbed (trout presence intermittent) and sympatric (constant trout presence). Using this classification, I tested the effects of trout chemical cues on galaxiid activity and refuge use in artificial channels. There were no differences in activity or refuge use between trout odour and there were no effects of population type or galaxiid size during both the day and the night. Using otolith weight-fish length relationships in galaxiids collected from each population type, I found that galaxiid growth rate was higher in disturbed streams than in stable streams either with or without trout. An experiment manipulating trout size and presence, over two months in a natural stream, found galaxiids from treatments without trout grew slower than those with trout. Slow growth rates in galaxiids above trout-migration barriers and in sympatry, combined with low growth rates in treatments without trout suggest that the mechanisms that regulate galaxiid growth are more complex than previously thought.

abstract: Novel resource inputs represent an increasingly common phenomenon in ecological systems as global change alters environmental factors and species distributions. In semiarid riparian areas, hydric pioneer tree species are being replaced by drought-tolerant species as water availability decreases. Additionally, introduced omnivorous crayfish, which feed upon primary producers, allochthonous detritus, and benthic invertebrates, can impact communities at multiple levels through both direct and indirect effects. In arid and semiarid systems of the American Southwest, crayfish may be especially important as detrital processors due to the lack of specialized detritivores. I tested the impact of virile crayfish (Orconectes virilis) on benthic invertebrates and detrital resources across a gradient of riparian vegetation drought-tolerance using field cages with leaf litter bags in the San Pedro River in Southeastern Arizona. Virile crayfish increased breakdown rate of drought-tolerant saltcedar (Tamarix ramosissima), but did not impact breakdown of Fremont cottonwood (Populus fremontii), Gooding's willow (Salix goodingii), or seepwillow (Baccharis salicifolia). The density and composition of the invertebrate community colonizing leaf litter bags were both heavily influenced by litter species but not directly by crayfish presence. As drought-tolerant species become more abundant in riparian zones, their litter will become a larger component of the organic matter budget of desert streams. By increasing breakdown rates of saltcedar, crayfish shift the composition of leaf litter in streams, which in turn may affect the composition and biomass of colonizing invertebrate communities. More research is needed to determine the full extent to which these alterations change community composition over time. / Dissertation/Thesis / M.S. Biology 2012

Master of Science / Department of Biology / Keith B. Gido / The upper Gila River basin in southwest New Mexico, USA is one of the few unimpounded drainage basins in North America and is a stronghold for the unique and endemic fishes west of the Continental Divide. Multiple non-indigenous fishes have been introduced to the Gila River and are a potential threat to native fishes, yet very little is known of the trophic ecology of the native and nonnative fishes. We used diet and stable isotopes collected from native and nonnative fishes to identify their trophic relationships and evaluate potential interactions in the upper Gila River basin during June-July, 2007 and 2008. Diet and stable isotope data indicated aquatic invertebrates were the primary food for both native and nonnative fishes. Native large-bodied fishes were mainly algivore/detritivores and native small-bodied fishes were primarily insectivores. Small-bodied nonnative fishes fed on detritus and aquatic invertebrates. Nonnative predators preyed on small-bodied fishes and predaceous aquatic invertebrates and had higher trophic positions than all native fishes. Although nonnative predators did not rely exclusively on native fishes as prey, their presence extended community food-chain lengths, and the combined predation on juvenile native fishes by multiple apex predators may threaten persistence of native fishes. The lack of concise evidence for negative effects suggested that impacts of nonnative predators were more subtle and confirmed the underlying complexity of a relatively simple community The extensive database on feeding relations of Gila River fishes allowed us to further understand how energy moves through ecosystems. Specifically, the goal of chapter two was to characterize variation in fish-community food web structure within and among study reaches on the Gila River using [superscript]13C and [superscript]15N stable isotopes. We hypothesized that food web structure would reflect variation in fish community structure, resource availability and environmental conditions across habitats. Food web structure in isotope bi-plot space was estimated using community-wide measures of trophic structure, mean trophic position, and food-chain length. Permutational multivariate analysis of variance indicated that indices of food web structure were more variable among than within reaches and this pattern was primarily associated with variation in trophicl area occupied by taxa in isotope bi-plot space and mean trophic position of those taxa. Variation in food web structure was significantly associated with fish species richness across macrohabitats but was weakly associated with abiotic reach-scale factors. Variation in food web structure was concordant with variation in fish community composition and suggested that factors influencing the distribution of fishes also influence food web structure.

A introdução de espécies nos ecossistemas pode levar a conseqüências difíceis de serem controladas, sendo que a competição por recursos alimentares talvez seja o principal meio pelo qual uma espécie introduzida possa afetar as espécies nativas, podendo ocasionar a extinção. Neste sentido, os estudos de alimentação tornam-se importantes ao fornecerem subsídios para compreender o funcionamento trófico de um ecossistema. Considerando estes aspectos, o objetivo da pesquisa foi conhecer a ecologia trófica das espécies introduzidas (Plagioscion squamosissimus e Cichla cf. ocellaris) e da espécie nativa (Geophagus brasiliensis), avaliando as possíveis interações entre elas. Para o estudo da dieta das espécies escolhidas, foram utilizados os exemplares capturados durante o desenvolvimento do projeto PROBIO 2. As coletas foram realizadas nos seis reservatórios do Médio e Baixo rio Tietê, no período de novembro de 2002 a fevereiro de 2004. Foram realizadas análises quantitativas (freqüência de ocorrência, método volumétrico e método gravimétrico) dos itens encontrados, caracterizando a preferência alimentar das espécies. Neste trabalho o acará (Geophagus brasiliensis), apresentou um hábito alimentar onívoro, consumindo principalmente larvas de Diptera, insetos aquáticos e microcrustáceos. A espécie (Cichla cf. ocellaris) apresentou um hábito alimentar piscívoro, consumindo principalmente peixes e crustáceos. A corvina (P. squamossisimus) foi considerada piscívora, apresentando um amplo espectro alimentar, consumindo principalmente peixes, insetos aquáticos e crustáceos. A ampla distribuição da espécie P. squamosissimus nos seis reservatórios do médio e baixo rio Tietê e a plasticidade alimentar evidenciada pela análise de conteúdo estomacal sugerem que a corvina exerce uma forte pressão sobre as espécies nativas, cuja dinâmica populacional pode ser alterada. / The species introduction into the ecosystems may lead to difficult consequences hard to be controlled and the competition for food resources being the main factor by which introduced species can affect the native species, even causing their extinction. In this sense, the feeding studies are important by supplying subsidies to understand the trophic functioning of an ecosystem. Considering these aspects, the objective of this research was to know the trophic ecology of the introduced species Plagioscion squamosissimus and Cichla cf. ocellaris and of the native species (Geophagus brasiliensis), evaluating the possible interactions between them. For the diet study of the chosen species, were used the samples collected during the development of the project PROBIO 2. Sampling was carried out in six reservoirs of the Middle and Low Tietê river, between November 2002 and February 2004. Qualitative analysis was done (occurrence frequency, volumetric method e gravimetric method) on the found items, characterizing the species feeding preference. In this work, the acará (Geophagus brasiliensis) presented an omnivorous feeding habit, mainly consuming Dipteral worms, aquatic insects and micro crustaceans. The species (Cichla cf. ocellaris) presented a piscivorous feeding habit, mainly consuming fishes and crustaceans. The curvina (P. squamossisimus) was considered piscivorous, presenting an ample feeding spectrum, mainly consuming fishes, aquatic insects and crustaceans. The ample distribution of the specie P. squamosissimus in the six reservoirs of the Middle and Low Tietê river and the plasticity revealed by the stomach content analysis, suggests that the curvina exercises a strong pressure over the native species, in which population dynamics can be changed.

For a number of years wildlife workers have realized the importance of the past histories of introduced species. Emphasis in recent years has been directed toward introductions because of the tremendous hunting and fishing pressures. Yearly increases in numbers of hunters and fishermen have been noted in Utah for the past forty years. It is hoped that this compilationo f the histories of the introduced game and fish species of Utah will be of value to sportsmen and wildlife managers alike in planning future introductions. The material included in this paper was obtained from United States Government reports, Utah Territorial reports, Utah State reports, newspapers and periodicals, personal interviews, and wardens' questionaires