Pulse subsidies account for a substantial proportion of resource availability in many systems, having persistent and cascading effects on consumer population dynamics, and the routing of energy within and across ecosystem boundaries. Although the importance of resource pulses is well-established, consumer responses and the extent of resource partitioning is not well understood. I identified a pulse of marsh cyprinodontoid, invertebrate, and sunfish prey, entering an estuary, which was met by an influx of both marsh and estuarine predators. In response to the pulse, consumers showed marked diet segregation. Bass consumed significantly more cyprinodontoids, bowfin consumed significantly more invertebrates, and snook almost exclusively targeted sunfishes. The diversity of the resource pulse subsidizes multiple consumers, routing pulsed production through various trophic pathways and across ecosystem boundaries. Preserving complex trophic linkages like those of the Everglades ecotone may be important to maintaining ecosystem function and the provisioning of services, such as recreational fisheries.

Title from PDF of title page (University of Missouri--Columbia, viewed on March 17, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Thesis advisor: Dr. Matthew E. Gompper. Vita. Includes bibliographical references.

Thesis (Ph. D.)--Flinders University, 2006. / Title from PDF t.p. (viewed on Mar. 11, 2007). Includes bibliographical references.

I quantified the bat assemblage associated with a Sonoran Desert riparian corridor at a wildland-urban interface using mist netting (2002-2005) to assess differential spatial and temporal resource use. My capture rate was high (17 species and 961 individuals) considering the aridity of the area; however, landscape complexity of this montane region undoubtedly contributes to foraging opportunities. I found that bats were distributed along the canyon when water was plentiful but their activity was concentrated at isolated pools during dry periods. I also found temporal variation in pool-use by the most frequently captured species. I conducted an acoustic study to measure bat-use between deciduous riparian and Sonoran desertscrub communities. I measured activity levels using number of acoustic call files. I found greater bat foraging in desertscrub and used a multidisciplinary approach to determine why bats might use the more arid environment. All capture data and supporting analyses are included in appendices.

Understanding the origins of biological diversity is a fundamental goal of evolutionary biology. A large body of theory attributes ecological and genetic diversification to divergent natural selection for resource specialization. This thesis examines adaptive radiation in response to selection for resource specialization in microcosm populations of the asexual bacterium Pseudomonas fluorescens. The general protocol for these experiments is to introduce a clonal population of Pseudomonas into a novel environment and to allow evolution to occur through the spontaneous appearance of novel genotypes carrying beneficial mutations. Adaptation can then be quantified through direct comparisons between evolved populations and their clonal ancestors. These experiments show that resource heterogeneity generates divergent natural selection for specialization on alternative resources, irrespective of the spatial structure of the environment. Adaptive radiation is possible in sympatry because of genetic trade-offs in the ability to exploit different resources, but these trade-offs are often not the result of antagonistic pleiotropy among loci that determine fitness on alternative resources. The rate of phenotypic diversification declines during adaptive radiation, apparently because the ecological opportunities required to support specialist lineages disappear as a consequence of initial diversification. The ultimate outcome of repeated instances of adaptive radiation is the evolution of a community of ecologically equivalent specialists that share similar adaptive traits, despite differences in the underlying genetic basis of specialization in replicate radiations. Comparisons with the literature on experimental evolution in microbial populations illustrate the results of this thesis are well-supported by experiments in a wide range of microbial microcosms.

Research Doctorate - Doctor of Philosophy (PhD) / In temperate New South Wales, most fish species in the family Labridae have not previously been investigated with available knowledge restricted primarily to photographic identification guides providing brief notes on species distribution, habitat preferences and identification. This information is inadequate for assessing the impact of labrid harvesting on rocky reef systems and for making informed management decisions for the protection of these fishes. Therefore, this study aimed to fill some of the significant gaps in the understanding of labrid assemblages associated with rocky reefs of temperate eastern Australia. This was accomplished by concentrating primarily on three species - Ophthalmolepis lineolatus, Notolabrus gymnogenis and Pictilabrus laticlavius - which are abundant and co-occur in shallow waters (less than 20 m depth) on the central coast of New South Wales. The methods used in this study included SCUBA surveys of labrid assemblages; in situ observations of labrid behaviour on SCUBA; and acquisition of labrid specimens for the extraction of intestines, gonads and otoliths, and for measurements of fish weight and length. <br /> Labrids were found to be the most species rich family in the study region and were the most abundant of all non-planktivorous fishes. Overall, a higher number of labrid species and a higher number of labrid individuals occurred in sponge garden habitat (15-22 m depth) compared to fringe (3-7 m) and barrens (8-15 m), owing to greater densities of O. lineolatus, Austrolabrus gymnogenis and Eupetrichthyes angustipes. The common labrids, N. gymnogenis, Achoerodus viridis and P. laticlavius, occurred at higher densities in fringe habitat due mostly to a higher representation of juveniles in this habitat. The effect of habitat on labrid assemblages was subject to small-scale variation between sites (separated by hundreds of metres) and experienced temporal changes due primarily to a substantial increase in the abundance of recruits coinciding with late summer and autumn (April-May). Behavioural observations revealed that the three focal species differed substantially in their spatial structure. O. lineolatus were found to be temporary reef residents using home ranges in excess of 2500 m2 for periods of up to 1 year before permanently emigrating outside these temporary home ranges. In contrast, N. gymnogenis exhibit strong site fidelity to reef patches of less than 600 m2 in which they remain for periods in excess of 2 years. Reef patches are shared by up to at least 10 juvenile and female individuals and a single, highly territorial male in a mating system suggestive of resource defence polygyny. An understanding of the spatial structure of P. laticlavius was constrained by its cryptic behaviour, but behavioural observations suggest this species is home ranging and establishes temporary territories for the purpose of feeding and/or reproduction. Intensive ethological observations allowed for the description and quantifying of several major behaviours in which all species typically engaged including encounters and interactions with other fishes, lying, use of shelter, side-swiping, bending, gaping, cleaning by clingfishes (Gobiesocidae) and colour change. The occurrence of these behaviours often demonstrated substantial differences among species (e.g. lying, shelter and bending) and/or experienced shifts with ontogeny (e.g. interactions and area usage). These trends generally remained consistent at different times of the day and periods of the year, and at both locations. Dietary analyses revealed O. lineolatus, N. gymnogenis and P. laticlavius are generalist carnivores feeding on a variety of benthic invertebrates including polychaetes, amphipods, decapods, gastropods, bivalves, polyplacophorans, echinoderms and cirripedes. Differences in the volumetric contribution of prey items in the guts of each species showed that food resources are partitioned among species and observations of foraging behaviour demonstrated a partitioning of microhabitats used for feeding. Ontogenetic shifts in diet and feeding microhabitats demonstrate that food resources are further partitioned within a species. However, overall morphological and behavioural similarities within a species results in greater competition occurring among individuals of the same species than among individuals of different species. This was reflected in higher rates of intra-specific interactions compared with interactions between labrid individuals of different species. Observations of feeding episodes revealed the bite rates of all species were typically unaffected by the time of day and period of year in which sampling occurred, but a location effect occurred for O. lineolatus and P. laticlavius. A reduction in bite rate with ontogeny occurred for N. gymnogenis. The population structure of the three species suggests each exhibits the typical labrid reproductive strategy of protogynous hermaphroditism. O. lineolatus and N. gymnogenis are both monandrous species, but the occurrence of some P. laticlavius males at small sizes and young ages suggests this species may be diandrous. Similarities occurred between O. lineolatus and N. gymnogenis in the size/age at which individuals sexually matured (c.a. 180 mm, 2 years) and changed sex (c.a. 280 mm, 4.6 years), but these events occurred at substantially smaller sizes (95 and 138 mm, respectively) and younger ages (les than 0.9 and 1.9 years, respectively) in P. laticlavius. Sectioned otoliths were used to determine that the longevity of O. lineolatus, N. gymnogenis and P. laticlavius was at least 13.4, 9.6 and 4.8 years, respectively. Ages were validated using marginal increment analysis. Timing of reproduction in each species was asynchronous with peaks in the reproductive activity occurring in late summer to early autumn (February-March) for O. lineolatus, mid winter (July) for N. gymnogenis and mid spring to early summer (October-December) in P. laticlavius.

Research Doctorate - Doctor of Philosophy (PhD) / In temperate New South Wales, most fish species in the family Labridae have not previously been investigated with available knowledge restricted primarily to photographic identification guides providing brief notes on species distribution, habitat preferences and identification. This information is inadequate for assessing the impact of labrid harvesting on rocky reef systems and for making informed management decisions for the protection of these fishes. Therefore, this study aimed to fill some of the significant gaps in the understanding of labrid assemblages associated with rocky reefs of temperate eastern Australia. This was accomplished by concentrating primarily on three species - Ophthalmolepis lineolatus, Notolabrus gymnogenis and Pictilabrus laticlavius - which are abundant and co-occur in shallow waters (less than 20 m depth) on the central coast of New South Wales. The methods used in this study included SCUBA surveys of labrid assemblages; in situ observations of labrid behaviour on SCUBA; and acquisition of labrid specimens for the extraction of intestines, gonads and otoliths, and for measurements of fish weight and length. <br /> Labrids were found to be the most species rich family in the study region and were the most abundant of all non-planktivorous fishes. Overall, a higher number of labrid species and a higher number of labrid individuals occurred in sponge garden habitat (15-22 m depth) compared to fringe (3-7 m) and barrens (8-15 m), owing to greater densities of O. lineolatus, Austrolabrus gymnogenis and Eupetrichthyes angustipes. The common labrids, N. gymnogenis, Achoerodus viridis and P. laticlavius, occurred at higher densities in fringe habitat due mostly to a higher representation of juveniles in this habitat. The effect of habitat on labrid assemblages was subject to small-scale variation between sites (separated by hundreds of metres) and experienced temporal changes due primarily to a substantial increase in the abundance of recruits coinciding with late summer and autumn (April-May). Behavioural observations revealed that the three focal species differed substantially in their spatial structure. O. lineolatus were found to be temporary reef residents using home ranges in excess of 2500 m2 for periods of up to 1 year before permanently emigrating outside these temporary home ranges. In contrast, N. gymnogenis exhibit strong site fidelity to reef patches of less than 600 m2 in which they remain for periods in excess of 2 years. Reef patches are shared by up to at least 10 juvenile and female individuals and a single, highly territorial male in a mating system suggestive of resource defence polygyny. An understanding of the spatial structure of P. laticlavius was constrained by its cryptic behaviour, but behavioural observations suggest this species is home ranging and establishes temporary territories for the purpose of feeding and/or reproduction. Intensive ethological observations allowed for the description and quantifying of several major behaviours in which all species typically engaged including encounters and interactions with other fishes, lying, use of shelter, side-swiping, bending, gaping, cleaning by clingfishes (Gobiesocidae) and colour change. The occurrence of these behaviours often demonstrated substantial differences among species (e.g. lying, shelter and bending) and/or experienced shifts with ontogeny (e.g. interactions and area usage). These trends generally remained consistent at different times of the day and periods of the year, and at both locations. Dietary analyses revealed O. lineolatus, N. gymnogenis and P. laticlavius are generalist carnivores feeding on a variety of benthic invertebrates including polychaetes, amphipods, decapods, gastropods, bivalves, polyplacophorans, echinoderms and cirripedes. Differences in the volumetric contribution of prey items in the guts of each species showed that food resources are partitioned among species and observations of foraging behaviour demonstrated a partitioning of microhabitats used for feeding. Ontogenetic shifts in diet and feeding microhabitats demonstrate that food resources are further partitioned within a species. However, overall morphological and behavioural similarities within a species results in greater competition occurring among individuals of the same species than among individuals of different species. This was reflected in higher rates of intra-specific interactions compared with interactions between labrid individuals of different species. Observations of feeding episodes revealed the bite rates of all species were typically unaffected by the time of day and period of year in which sampling occurred, but a location effect occurred for O. lineolatus and P. laticlavius. A reduction in bite rate with ontogeny occurred for N. gymnogenis. The population structure of the three species suggests each exhibits the typical labrid reproductive strategy of protogynous hermaphroditism. O. lineolatus and N. gymnogenis are both monandrous species, but the occurrence of some P. laticlavius males at small sizes and young ages suggests this species may be diandrous. Similarities occurred between O. lineolatus and N. gymnogenis in the size/age at which individuals sexually matured (c.a. 180 mm, 2 years) and changed sex (c.a. 280 mm, 4.6 years), but these events occurred at substantially smaller sizes (95 and 138 mm, respectively) and younger ages (les than 0.9 and 1.9 years, respectively) in P. laticlavius. Sectioned otoliths were used to determine that the longevity of O. lineolatus, N. gymnogenis and P. laticlavius was at least 13.4, 9.6 and 4.8 years, respectively. Ages were validated using marginal increment analysis. Timing of reproduction in each species was asynchronous with peaks in the reproductive activity occurring in late summer to early autumn (February-March) for O. lineolatus, mid winter (July) for N. gymnogenis and mid spring to early summer (October-December) in P. laticlavius.

Thesis (Ph.D.)--Baylor University, 2009. / Includes bibliographical references (p. 104-117).

The Caprellidae are a specialized suborder of Amphipoda, which are highly modified for a semisessile life. Caprellids exhibit direct development and brood their young. The suborder is exclusively marine and commonly found on filamentous algae, sea grasses and fouling communities. Most published works on caprellids have been primarily concern~d with systematics (Caine, 1974; Dougherty, 1943; Laubitz, 1970, 1972; McCain, 1968, 1975), although a few recent studies have dealt with ecology and ethology (Bynum, 1978; Caine, 1977; Keith, 1969, 1971; Lewbel, 1978; Saunders, 1966). This study examines·spatial and temporal variations in distribution, abundance and population structure as well as describing intraspecific aggressive behavior of Caprella californica Stimpson. ~- californica is dioecious and has marked sexual dimorphism in both its size and secondary sex characteristics. It is found from San Diego to the South China Sea (Laubitz, 1970), and is the dominant caprellid in the Zostera marina beds of the local bays and is a major diet item for many of the eel grass associated fishes. There is a preponderance of females in the population as well as a size-specific distribution of the proportion of the sexes.

Pocket gophers (family Geomyidae) are the dominant burrowing rodents in North America today. Their fossil record is also incredibly rich; in particular, entoptychine gophers, a diverse extinct subfamily of the Geomyidae, are known from countless teeth and jaws from Oligocene and Miocene-aged deposits of the western United States and Mexico. Their postcranial remains, however, are much rarer and little studied. Yet, they offer the opportunity to investigate the locomotion of fossil gophers, shed light on the evolution of fossoriality, and enable ecomorphological comparisons with contemporaneous rodents. We present herein a quantitative study of the cranial and postcranial remains of eight different species of entoptychine gophers as well as many contemporary rodent species. We find a range of burrowing capabilities within Entoptychinae, including semifossorial scratch-digging animals and fossorial taxa with cranial adaptations to burrowing. Our results suggest the repeated evolution of chisel-tooth digging across genera. Comparisons between entoptychine gophers and contemporaneous rodent taxa show little ecomorphological overlap and suggest that the succession of burrowing rodent taxa on the landscape may have had more to do with habitat partitioning than competition.