Orientador: José Augusto Senhorini / Resumo: Alterações ambientais provocadas por atividades agropecuárias, barramentos, expansão urbana e poluição figuram entre as principais ameaças à conservação da ictiofauna no País. Na bacia do rio Doce, por exemplo, 9 de suas 70 espécies encontram-se listadas na portaria MMA 445/2014. O rompimento da barragem de rejeitos de mineração de Fundão, ocorrido em 2015, pode ter ocasionado uma piora no estado de conservação de algumas dessas espécies, bem como a inclusão de outras nas categorias de ameaças. Assim, torna-se imperativo a realização de estudos e ações para a conservação desses peixes. Entre as áreas reconhecidas como relevantes para a conservação da ictiofauna do rio Doce destaca-se a bacia do rio Santo Antônio. O presente trabalho teve como objetivo realizar estudos focados em biologia básica e reprodutiva para fornecer subsídios a conservação das espécies ameaçadas de extinção endêmicas da bacia do rio Doce. As coletas foram realizadas no rio Santo Antônio no Município de Ferros – MG. Foram coletados espécimes de Henochilus wheatlandii, Steindachneridion doceanum e Brycon opalinus os quais foram encaminhados ao ICMBio/CEPTA e mantidos em tanques e viveiros com renovação constante de água. Entre as espécies capturadas, H. wheatlandii foi a mais abundante com indicativos de possuir uma população saudável. As demais espécies foram menos abundantes e possivelmente podem estar em declínio na região. Os juvenis de H. wheatlandii se mostram sensíveis a variações de temperatura e ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Environmental changes caused by agricultural activities, buses, urban sprawl, and pollution are among the main threats to ichthyofauna conservation in the country, as an example, 9 out of 70 species of the Doce river basin are listed in MMA 445/2014 ordinance. The Fundão mining tailings dam rupture of 2015 may have led to aggravation in the conservation status of some of these species, as well as the inclusion of others in higher threat categories. Thus, it is imperative to develop studies and actions for these fish conservation. Among the areas of Doce river basin that are recognized as relevant for ichthyofauna conservation, Santo Antônio river basin takes a place of highlight. Our work aimed to develop studies focused on species basic reproductive biology to provide support for the conservation of endangered endemic species of the Doce river basin. The collections were done in Santo Antônio river, located in Ferros – MG. Specimens collected of Henochilus wheatlandii, Steindachneridion doceanum, and Brycon opalinus were sent to ICMBio / CEPTA and kept in tanks with constant water renewal. Among the species captured, H. wheatlandii was the most abundant, with indications of having a healthy population. The other species were less abundant and possibly may be declining in the region. The H. wheatlandii juveniles showed to be sensitive to temperature variations and infestation by Ichthyophthirius multifiliis. On the other hand, the adults of the other three species adapted qui... (Complete abstract click electronic access below) / Mestre

Abstract not available

Understanding the relationship between organisms and their environment is particularly important for the conservation and management of endangered species. The kakapo (Strigops habroptilus, Gray 1845) is a critically endangered, lek breeding, flightless nocturnal parrot endemic to New Zealand. In April 1998, a total population of fifty-six kakapo was known to survive on offshore islands. Twenty-six kakapo, thirteen males and thirteen females, were temporarily transferred to Pearl Island (518 ha), southern Stewart Island, from April 1998 to April 1999. The translocation of kakapo to Pearl Island, and subsequent breeding season, provided an ideal experimental framework to study kakapo dispersal, movement patterns, home range development, habitat selection, and lek development during the non-breeding and breeding seasons. A total of 4425 radio locations were analysed for all twenty-six birds, with a mean error polygon of 0.03 ha and an estimated average radio telemetry error of 21.6 m. Various home range analysis techniques were used to estimate kakapo home range size and overlap including: minimum convex polygons (MCP), modified minimum convex polygons (MMCP), harmonic mean analysis, adaptive kernel methods and cluster analysis. Estimates of kakapo home range size differed significantly depending on the method used (ANOVA, general linear model: F₁₃, ₁₀₇₆ = 63.99, p < 0.0001) and the season (F₂, ₁₀₇₆ = 160.75, p < 0.0001). Breeding home range size was significantly larger than non-breeding range size (mean difference = 67.6 ha, t₂₅ = 15.27, p < 0.0001). Calculations from 100% MCP and 95% harmonic mean analysis resulted in larger estimates of home range size and overlap compared to other methods. Cluster and kernel analyses appeared to give the most accurate home range representation for kakapo. Core home range areas showed a greater degree of similarity between methods. Male and female mean annual home range size did not differ significantly, whereas males had significantly (p < 0.05) larger home ranges than females during the nonbreeding season. Minimum convex polygons and harmonic mean analysis suggested that there was no significant difference in the way in which males and females interacted with each other. Kernel and cluster analyses indicated that females would overlap a greater proportion of another bird�s home range than males would. Cluster analysis also indicated that a female would have more of her home range occupied by another bird than a male would. The fact that different methods produced different quantitative results is an important consideration when using home range analysis to make conservation management decisions. Researchers must determine which method is the most appropriate for a particular research objective, species, or study area. The application of geographical information systems, ERDAS image classification techniques and global positioning systems was an integral part of this study. A large-scale vegetation classification map of Pearl Island was produced in order to quantify habitat selection by kakapo. The unsupervised classification technique produced the least accurate vegetation map, with an accuracy measure of 17-23%, compared to 52% for the supervised classification. The highest accuracy was obtained using an integrated approach involving inductive classification and deductive mapping, resulting in a vegetation classification map which correctly classified 95% of vegetation samples. Thirty-seven ecotone classes were identified and a total ecotone length of approximately 124 km was detected. Resource selection ratios and resource selection functions were estimated using a combination of discrete, continuous and area-based habitat variables. Circular buffers around used and available point locations were generated to determine whether kakapo selectively use vegetation mosaics. The probability of selection increased with increasing species diversity in each 75-metre radius buffer. Kakapo selected habitat mosaics and vegetation types with higher species diversity and moderate to high abundance of mature rimu and yellow silver pine trees.

The White-browed Treecreeper Climacteris affinis is one of many woodland-dependent birds that are at risk from the encroachment of human-dominated land-uses into natural landscapes. The White-browed Treecreeper inhabits semi-arid woodlands in north-west Victoria, Australia, a vegetation community that has undergone extreme modification in the last century due to the expansion of agriculture in the region. Extant woodlands represent only 10% of the original woodland cover in the region, and are highly fragmented and disturbed in many districts. Thus, the survival of the White-browed Treecreeper may depend on active management. However, current knowledge of the ecology and biology of this species is virtually non-existent, and inadequate for informed and effective conservation actions. The aim of this thesis is to redress this situation and provide the ecological basis for sound conservation management of the species. The thesis consists of two parts: an investigation of habitat use at three spatial scales and a study of the social organization, nesting requirements, breeding behaviour and reproductive success of a population of White-browed Treecreepers. Fifty-six patches of remnant woodland in north-west Victoria were surveyed to determine the factors affecting the occurrence of the White-browed Treecreeper at the regional scale. It was detected in 16 patches, and was largely confined to two core districts - Yarrara and, Wyperfeld (Pine Plains). The floristic composition of the dominant tree species was an important determinant of patch occupancy, with the results providing quantitative support for the previously suspected affinity for Belah Casuarina pauper and Slender Cypress-pine Callitris gracilis — Buloke Allocasuarina luehmannii woodlands. However, the absence of the White-browed Treecreeper from several districts was due to factors other than a lack of appropriate habitat. Demographic isolation - the distance from the focal patch to the nearest population of the White-browed Treecreeper - was the most important variable in explaining variation in patch occupancy. Patches isolated from other treecreeper populations by more than 8.3 km in landscapes of non-preferred native vegetation, and 3 km in agricultural landscapes, were unlikely to support the White-browed Treecreeper. The impact of habitat loss and fragmentation on the capacity of individuals to move through the landscape (i.e. functional connectivity) is considered in relation to disruption to dispersal and migration, and the potential collapse of local metapopulations. Habitat use was then examined in a network of patches and linear strips of Belah woodland embedded in a predominantly cultivated landscape. A minimum area of 18.5 ha of Belah woodland was identified as the most important criterion for patch occupancy at the local scale. This landscape appeared to be permeable to movement by the White-browed Treecreeper, facilitated by the extensive network of linear habitat, and clusters of small to medium fragments. The third scale of habitat use investigated the frequency of use of 1-ha plots within tracts of occupied woodland. It is important to discriminate between habitat traits that operate at the population level, and those that act as proximate cues for habitat selection by individuals. Woodlands that have high tree density, extensive cover of low-stature shrubs, abundant lichen, a complex vertical structure, and relatively low cover of grass and herbs are likely to support larger populations of the White-browed Treecreeper. However, individuals appeared to be using tree dominance (positive) and tall shrub cover (negative) as proximate environmental stimuli for habitat selectivity. A relatively high cover of ground lichen, which probably reflects a ground layer with low disturbance and high structural complexity, was also a reliable indicator of habitat use. Predictive models were developed which could be used to plan vegetation management to enhance habitat for the White-browed Treecreeper. The results of the regional, landscape and patch-scale investigations emphasise that factors operating at multiple spatial scales influence the suitability of remnant vegetation as habitat for the White-browed Treecreeper. The White-browed Treecreeper is typical of many small Australian passerines in that it has high annual survival, small clutches, a long breeding season, multiple broods and relatively low reproductive rates. Reproductive effort is adjusted through the number of clutches laid rather than clutch size. They occupy relatively large, all-purpose territories throughout the year. However, unlike many group territorial birds, territory size was not related to the number of occupants. The White-browed Treecreeper nests in tree hollows. They select hollows with a southerly orientation where possible, and prefer hollows that were higher from the ground. At Yarrara, there was considerable spatial variation in hollow abundance that, in concert with territorial constraints, restricted the actual availability of hollows to less than the absolute abundance of hollows. Thus, the availability of suitable hollows may limit reproductive productivity in some territories, although the magnitude of this constraint on overall population growth is predicted to be small. However, lack of recruitment of hollow-bearing trees would increase the potential for hollow availability to limit population growth. This prospect is particularly relevant in grazed remnants and those outside the reserve system. Facultative cooperative breeding was confirmed, with groups formed through male philopatry. Consequently, natal dispersal is female-biased, although there was no skew in the sex ratio of the fledglings or the general adult population. Helpers were observed performing all activities associated with parenting except copulation and brooding. Cooperatively breeding groups enjoyed higher fledgling productivity than simple pairs, after statistically accounting for territory and parental quality. However, the difference reflected increased productivity in the 1999-breeding season only, when climatic conditions were more favourable than in 1998. Breeding commenced earlier in 1999, and all breeding units were more likely to attempt a second brood. However, only breeders with helpers were successful in fledging second brood young, and it was this difference that accounted for the overall discrepancy in productivity. The key mechanism for increased success in cooperative groups was a reduction hi the interval between first and second broods, facilitated by compensatory reductions in the level of care to the first brood. Thus, females with helpers probably achieved significant energetic savings during this period, which enabled them to re-lay sooner. Furthermore, they were able to recommence nesting when the fledglings from the first brood were younger because there were more adults to feed the dependent juveniles. The current utility, and possible evolutionary pathways, of cooperative breeding is examined from the perspective of both breeders and helpers. Breeders benefit through enhanced fledgling productivity in good breeding conditions and a reduction in the burden of parental care, which may impart significant energetic savings. Further, breeders may facilitate philopatry as a means for ensuring a minimum level of reproductive success. Helpers benefit through an increase in their inclusive fitness in the absence of opportunities for independent breeding (i.e. ecological constraints) and access to breeding vacancies in the natal or adjacent territories (i.e. benefits of philopatry). However, the majority of breeding unit-years comprised unassisted breeders, which suggests that pairs are selectively favoured under certain environmental or demographic conditions.

The documented decline of amphibian populations over the past two decades has increased attention towards amphibian conservation. Much of this attention has been focused on testing hypotheses as to the causal factors of these declines, however providing convincing data to support any of these hypotheses has proved difficult. The testing of these hypotheses and the implementation of endangered species recovery programs has been restricted by a lack of knowledge of the ecology and population demography of amphibian species that have suffered dramatic declines. This thesis presents aspects of the research phase of the recovery program for the Southern Corroboree Frog, Pseudophryne corroboree, a species that declined to very low numbers during the early 1980's. In particular, this research aimed to determine the distribution, abundance, population dynamics and demography of this rare species. A complete reassessment of the conservation status of P. corroboree was undertaken and the nature of the persistence of this species across the landscape was analysed. Temporal trends in abundance and its relationship with population size were also investigated. Early life-history survivorship and recruitment to metamorphosis were studied at the scale of individual nest sites and populations, and the adult male population age structure and annual mortality were investigated using skeletochronology. The shout/response survey technique was used to survey and monitor the number of breeding male P. corroboree during this study. This method was found to provide consistent results when the surveys were conducted over a short (two week) period during the peak breeding season in January. Neither time of day, nor the number of males present at a pool, was found to influence the level of responsiveness of male P. corroboree to the shout/response technique. Variation in the number of responding males to the shout/response technique through the breeding season, assessed at a single site over two seasons, was unimodal with the peak responding period occurring during the last two weeks of January during both the 1998 and the 1999 breeding seasons. A systematic survey covering 213 sites across the entire historic distribution of P. corroboree found this species to be persisting at 79 sites. The majority of these sites were in the northwestern portion of the species former range, around the Jagungal Wilderness area, while no extant sites were found in the south-eastern portion of the species former range in the Smiggin Holes and Perisher Blue ski resorts area. The overall abundance of males at persistent sites was extremely low, with 92 percent of sites having fewer than ten responding males. Only one site was found to support greater than fifty responding males. A logistic regression analysis found the persistence of P. corroboree to be associated with increased number of pools within a site, decreased distance to nearest extant population and geographic position (latitude and longitude) in the landscape. While annual variation was observed in the number of breeding males for individual sites, there was no overall trend for an increase or decrease in the number of males, regardless of population size. The average annual extinction rate for local populations was five percent during this study, with those populations becoming extinct having very few breeding males (between one and three) during the previous season. Embryonic and tadpole survivorship was monitored for individual nests at three sites across three years. Recruitment to metamorphosis for P. corroboree was characterised by high variation in survivorship between nest sites, populations and years, while overall recruitment for nest sites was skewed towards lower survivorship. Average nest survivorship to metamorphosis across all sites and years was ten percent but the skewed nature of this survivorship meant that the majority of nest sites attained very low or no survivorship. The low proportion of nest sites that did attain high survivorship provided the greatest contribution to overall recruitment. The levels of embryonic and tadpole mortality observed in this study would be providing a considerable contribution to the regulation of current population sizes. The greatest level of early life-history mortality was observed during the late autumn/winter egg and tadpole stage, with high survivorship during the summer and early autumn egg stage and the post-winter tadpole stage. The estimated sex ratio for seven populations, based on the number of eggs within male nest sites, indicated that for most populations, regardless of population size, there was a greater proportion of females to males. In general, the estimated sex ratio of smaller populations showed greater annual variation and had a lower average number of females to males than the single large population. Tadpole surveys conducted across remnant populations during both 1998 and 1999 found recruitment to metamorphosis to be very low for the majority of populations. A third of all populations during both years attained no recruitment to metamorphosis, with those populations that did attain recruitment typically having fewer than 20 tadpoles. While sites with more frogs generally recruited more tadpoles, there was no strong relationship between population size and the number of tadpoles recruited per male at the scale of either pool or site. There was also no significant difference in recruitment levels between the two years. Tadpole surveys across breeding pools within the single large population also found very low tadpole abundance. There was no strong relationship between the number of male frogs at a pool and the number of tadpoles per male and there was no significant difference in tadpole abundance between the two years. Based on the low density of males at pools and sites (typically less than five), and the skewed nature of nest survivorship identified from monitoring individual nest sites, it seems likely that both deterministic and stochastic factors are influencing recruitment levels in remnant populations of P. corroboree. This study determined that adult male P. corroboree could be accurately aged using the technique of skeletochronology, and this technique was used to determine the adult male population age structure for three populations. The results indicated that adult male P. corroboree can reach sexual maturity from metamorphosis in three years, but the majority of individuals take four years. The oldest individual identified in this study was nine years old from metamorphosis. The adult male age structure at the single large site showed very little annual variation, whereas the two smaller populations showed highly pulsed age structures from one year to the next. The size of adult males was found to be a poor predictor of age. Annual adult male survivorship, calculated by following cohorts from one year to the next, was 55 percent. Based on this calculation of annual adult male survivorship, it seems likely that the initial decline in P. corroboree involved increased levels of adult mortality. The results of this study indicate that the persistence of. corroboree in the wild is precarious in the short-term. For this reason, it is recommended that efforts be undertaken to secure this species ex situ. Attempts to increase population numbers in the wild would greatly benefit from determining the factor(s) that have caused the decline in this species, however, failure to do so should not preclude field experimental management aimed at developing technique to increase the size of remnant populations. This is because it is likely that small population stochasticity is contributing to the current regulation of population size and it is possible that the factors that caused the decline in this species cannot be removed from the environment.

This thesis discusses both theoretical and practical considerations inherent in conducting community-based research within a case study of sea turtle conservation in Baja California, Mexico. A brief background, including the general ecology, status and distribution of sea turtles of the Baja peninsula is presented, with an overview of the current and historic use and management of sea turtles. Several sets of theories provide the context within which the case example is analyzed. A discussion of how concepts of "science" and "knowledge" are shaped and how these perceptions impact choices made in natural resource management and planning is presented. This includes a brief discussion of conservation ethics and conservation rationale, as well as a review of the debates surrounding indigenous knowledge and its application in conservation. A review of community-based efforts in sea turtle conservation is also presented. The data and analysis offered in this thesis is the result of two field seasons working as a member of an interdisciplinary sea turtle conservation team: conducting biological studies, surveys, informal and semi-structured interviews and participant observation. The major goal of this research project was to evaluate a people-oriented approach to conservation. The objectives of the Baja sea turtle conservation project included: the involvement of fishing communities in the development of conservation projects, the involvement of local students and fishermen in the collection of data and the public sharing of research results on a regular basis. Results of this case study suggest that through dependence on the host community for food, equipment, labor and guidance a special connection was established, fostering trust and building the partnerships necessary for long-term conservation success. For this reason, fishermen and other members of the local host communities were more willing to cooperate with outsiders and share their intimate knowledge of their environment - including information on the daily movements and distribution of sea turtles. It is crucial that the fishermen feel empowered before they choose to participate in the sea turtle conservation efforts. They must be viewed, and view themselves, as an integral part of the conservation team contributing valuable knowledge and ideas, not just acting as boat drivers and guides for outside researchers within the host community. Community meetings served as an outlet to voice concerns and share information. The active involvement and participation of local communities is a highly effective tool in the sea turtle conservation efforts in the region. / Graduation date: 2002

Thesis (M.S.)--Oregon State University, 2007. / Printout. Includes bibliographical references (leaves 198-204). Also available on the World Wide Web.

The coastal zone of Belize is home to the largest recorded number of the threatened Antillean manatee (Trichechus manatus manatus) within the species' Caribbean range. The objectives of my study were: (1) to determine long-term trends in aerial survey counts and indices of the manatee population in the coastal zone of Belize; and (2) to examine the seasonal change in manatee distribution among habitats in the coastal zone. Standardized extended-area aerial surveys were conducted along the entire coastline of Belize in the dry and wet seasons of 1997, and 1999 - 2002. Manatees were counted in five habitat categories: cay, coast, estuary, lagoon, and river. Total sightings per survey ranged from 90 to 338; the greatest number was counted in the 2002 wet season. Calf percentage ranged from 5 to 13. A slight negative trend in total counts was significant for dry-season, not wet-season surveys, indicating an interactive effect of season and year. Based on analysis of variance, the Abundance Index (transformed manatee sightings per hour) did not differ significantly among years, although it varied significantly within year by season and habitat by season. In applying a spatial approach, the general survey route was buffered 1 km on both sides, and 1 km grids were overlaid and classified by habitat type. The presence or absence of each cell for each survey was used in likelihood ratio tests of the single and interactive effect of season and habitat. The Index for river habitat was higher in the dry season, while cay habitat was higher in the wet season. Overall, near-shore habitat (estuary, lagoon, and river) showed a higher Index than did the offshore habitat (cay and coast) although the total number of sightings was higher offshore. Considering the interactive effect of year, season, and habitat, long-term studies are needed, in both seasons, and among all habitats to account for variation. Continued broad-scale surveys, along with metapopulation analysis would fine-tune the understanding of specific sites, enhancing integrated coastal zone management for protected species and their habitat systems.

Oak wilt is a fatal disease of oaks caused by the fungus Ceratocystis fagacearum. Loss or degradation of habitat due to the disease may negatively affect the federally endangered golden-cheeked warbler (Setophaga chrysoparia). To assess the impact of oak wilt on golden-cheeked warblers, I investigated its influence on habitat selection and quality. I used remote sensing to estimate the amount of potential golden-cheeked warbler habitat currently affected by oak wilt, to predict the amount of potential habitat likely to be affected in the near future, and to assess the current probability of warbler occupancy in areas affected by oak wilt historically. I also quantified vegetative characteristics to assess overstory vegetation and regeneration in areas affected by the disease. I found proportional occupancy and territory density in unaffected areas to be, respectively, 3.5 and 1.8 times that of affected areas. Pairing success was 27% lower for territories containing oak wilt but fledging success was not affected. I estimated that 6.9% of potential golden-cheeked warbler habitat and 7.7% of the total area within my study region was affected by oak wilt in 2008. By 2018, I predicted that 13.3% of potential golden-cheeked warbler habitat and 16.0% of the study region would be affected by the disease. Using historical imagery, I found that areas affected by oak wilt in the past are less likely to be classified as current potential warbler habitat than areas never affected by the disease. I found no differences between the understory vegetation of affected and unaffected areas but that oaks were more common in the overstory than in the understory, suggesting that species composition in affected areas may shift in the years following an outbreak of the disease. My results suggest that the presence of oak wilt negatively influences habitat selection and quality for golden-cheeked warblers, likely due to reduced canopy cover in susceptible oak species. Additionally, oak wilt frequently occurs in golden-cheeked warbler habitat and will continue to spread into warbler habitat in the coming years. Future management efforts should address the threat oak wilt poses to golden-cheeked warblers by incorporating applicable preventative measures.

Humans are modifying the global landscape at an unprecedented scale and pace. As a result, species are declining and going extinct at an alarming rate. Here, I investigate two main aspects of species’ declines: what factors are contributing to their declines and how effective our conservation efforts have been. I assessed one of the main mechanisms for protecting species by looking at the Endangered Species Act (ESA) in the United States. I examined three separate indicators of species declines for different groups of species: range contractions in Canadian imperilled species, declines in abundance in global amphibian populations and increases in temporal variability in abundance in North American breeding birds. I found that change in recovery status of ESA listed species was only very weakly related to the number of years listed, number of years with a recovery plan, and funding. These tools combined explained very little of the variation in recovery status among species. Either these tools are not very effective in promoting species’ recovery, or species recovery data are so poor that it is impossible to tell whether the tools are effective or not. I examined patterns of species’ declines in three different groups in relation to a number of anthropogenic variables. I found high losses of Canadian imperiled bird, mammal, amphibian and reptile species in regions with high proportions of agricultural land cover. However, losses of imperiled species are significantly more strongly related to the proportion of the region treated with agricultural pesticides. This is consistent with the hypothesis that agricultural pesticide use, or something strongly collinear with it (perhaps intensive agriculture more generally), has contributed significantly to the decline of imperiled species in Canada. Global increases in UV radiation do not appear to be a major cause of amphibian population declines. At individual sites, temporal changes in amphibian abundance are not predictably related to changes in UV intensity. Variability in species’ abundance of North American breeding birds, after accounting for mean abundance, is not systematically higher in areas of high human-dominated land cover or climate change. Rather, it appears that areas with a high proportion of human-dominated cover come to have a higher proportion of highly abundant, and thus more variable, species.