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Habitat loss and predation are threatening many shorebird populations worldwide. While habitat preservation often is preferable, sometimes habitat needs to be restored or created in order to stave off immediate declines. The Great Plains population of piping plovers (Charadrius melodus) was listed as threatened in 1986, and habitat loss and predation appear to be limiting the growth of this population. On the Missouri River, piping plovers nest on sandbars, but the damming of the mainstem of the Missouri in the mid-twentieth century reduced the natural capacity of the Missouri River to create sandbar habitat. In 2004, the United States Army Corps of Engineers (USACE) implemented a habitat creation project on the Gavins Point Reach of the Missouri River (stretch of river immediately downriver from the Gavins Point Dam) in an effort to promote recovery of piping plovers and the endangered least tern (Sternula antillarum). The USACE built 3 sandbars in 2004 – 2005 and built another sandbar on Lewis and Clark Lake in 2007. We studied the population dynamics of piping plovers in relationship to this newly engineered habitat. We monitored 623 nests on 16 sandbar complexes, to evaluate habitat selection, determine the factors affecting nesting success, and compare nesting success between natural and engineered habitat. From these 623 nests, we banded 357 adults and 685 chicks to investigate the factors affecting adult and juvenile survival. We used a logistic-exposure model to calculate nest survival. Adult and juvenile survival was calculated using Cormack-Jolly-Seber based models in Program MARK. We used the estimates from these studies to create a matrix population model for piping plovers nesting on the Gavins Point Reach. We used this model to predict the effects of engineered habitat on the population growth rate. Piping plovers selected for engineered sandbars and against natural and natural/modified habitats. Daily survival rate (DSR) on engineered habitats was significantly higher than on natural or natural modified habitats (log odds: 2.71, 95% CI: 1.20 – 6.08). Predator exclosures around nests did not affect DSR after controlling for the effects of date, nest age, and clutch size. Piping plover juvenile survival to recruitment was negatively related to nesting density on the relatively densely populated engineered sandbars. On the less dense natural sandbars, survival to recruitment was positively correlated with density. Adult survival did not appear to be related to density within our study. Movement within the study area was related also to density. Juveniles from densely populated engineered sandbars were more likely to leave engineered habitat to nest on natural sandbars than were juveniles hatched on less densely populated engineered sandbars. Movements among sandbars by breeding adults suggested that adults preferred engineered habitat. It is possible that juveniles moved to natural habitats because they were unable to compete with adults for the more desirable engineered habitats. Adults and juveniles emigrated from the study area at a higher rate after the 2006 breeding season, a year when water discharge was higher, nesting densities were higher, and reproductive success was lower (as a result of predation) than in the other years. Deterministic modeling suggested that engineered habitat significantly increased population growth. Decreased productivity over time and associated predicted negative population growth suggest that the amount of engineered habitat created was inadequate to sustain population growth, and/or that relatively high water discharge and nesting densities coupled with low reproductive rates and high emigration rates could lead to rapid declines in the plover population. Continued research is needed to determine the effects of these factors on long-term population growth. Our results suggest that habitat creation could be a viable short-term solution to population declines in shorebird populations limited by habitat loss, but high densities and increased predation associated with habitat creation indicate that other, long-term solutions may be required. / Ph. D.

Increased temperatures due to anthropogenic-induced climate change may raise the threat of extinction for taxa with sessile life histories (e.g., plants) in the near future. Linking climate change models to demographic models may provide useful insights into the potential effects of environmental changes on rare plants, and therefore aid in their current and future conservation. Population demographers generally agree that mechanistic models from a reductionist perspective are necessary to test assumptions in population drivers. For the first study, I assessed the climate vulnerability of a rare plant species, Pyrrocoma radiata, with a mechanistic model of four climatically-similar populations. I used environmentally-driven demographic models to estimate vital rates and population sizes from a nonlinear, nonparametric regression with local climate variables. I assessed the utility of this environmentally-correlated, stage-structured population matrix model compared to a stationary model of independent and identically-distributed environmental stochasticity. I then simulated future population projections based on climate conditions predicted by General Circulation Models (GCMs) under opposing emission scenarios. The second study hopes to answer population-level questions using a traditionally community-level method, non-metric multidimensional scaling, which considers correlation structure between response variables and can be used to find environmental correlates of the ordination axes. Demographic data on a threatened perennial, Astragalus tyghensis, were collected from five sites in the Tygh Valley, OR. I considered correlation structure between demographic vital rates to find environmental correlates of the ordination axes. The search for an environmental driver of population vital rates was successful for the two study species. Previous year dry dormant season precipitation likely affects the fertility rates a year later in P. radiata populations, and dry growing season reference evapotranspiration rates positively correlated with a growth gradient in A. tyghensis. Based on predicted precipitation, P. radiata is expected to rapidly decline by 2050, but this may be due to biases in the two GCMs and reliance on only one environmental factor. The NMS ordination adequately captured most of the variation in transition elements for the years and populations from A. tyghensis demographics. I provided support to the claim that model predictions can improve with the inclusion of mechanistic relationships. The inclusion of abiotic drivers in models used to predict population trends is supported by our study and may enhance predictive power in population viability assessments under changing climates. / Graduation date: 2013

The critically endangered blue-eyed black lemur (Eulemur flavifrons) is one the leaststudied day active lemurs because of the recent rediscovery and limited distribution. This thesis examined the habitat use, reproductive parameters and the population viability of the blue-eyed black lemur population at Ankarafa Forest, Sahamalaza-Iles Radama National Park, Madagascar. The main aim was to gather fundamental information on the natural history of the blue-eyed black lemur and to propose conservation approaches for both the species and its habitat. Data were collected over 14 month-period between 2006 and 2008. Six groups of the blue-eyed black lemur were studied, four of which were collared and two uncollared. Ankarafa Forest, the largest forest blocks of the Sahamalaza-Iles Radama National Park, is dominated mainly by Mangifera indica, Garcinia pauciflora, Sorindeia madagascariensis, Grangeria porosa, Bambou sp. and Mascarenhasia arborescens species. The forest is vulnerable to degradation by both anthropogenic activities and abiotic factors. The population density of the blue-eyed black lemur at Akarafa Forest was estimated to be 97.3 individuals km-², with group size ranging from 4 to 11 individuals. The home range use and day path length of the blue-eyed black lemur varied seasonally. The lemur occupied a larger home range in the dry season than in the wet season. The age of first reproduction in the blue-eyed black lemurs is about 3 years. They bear offspring seasonally (late August-October), all adult females in groups bred and females produce singletons offspring. Females were dominant over males. The sex-ratio at birth was male-biased but not significantly different from 1:1. Females were the primary caretakers of infants but group members other than the mother also provided alloparental care. For the first 3 weeks of life, infants were carried constantly on their mothers’ bellies. Infants developed independent locomotion and fed on solid food by 10 weeks. Increased probability of extinction, as shown by population viability models of the blue-eyed black lemur population, is affected by various of their reproductive parameters. However, these do not account for changes in their primary habitat forest. The latter is under increased human pressure and continues to decline in area. Education awareness and community involvement are required if the habitat and the blue-eyed black lemur are to survive. Findings of this study serve not only important data to understand the life history of the blue-eyed black lemur but also suggest conservation approaches for both the species and its natural habitat. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2009.

To assess the status of a rare plant species, we must first understand the factors that affect the size of populations and their numbers. In this thesis, I study processes affecting plant species prosperity on local scale (paper 1), factors influencing species distribution in landscape and ability of species to colonize new habitats (paper 2) and species traits responsible for gene flow between established populations (paper 3). Since I work with rare plants, I also aim to turn theoretical knowledge into practical recommendations for nature conservation (paper 4) to help effectively preserve rare and endangered species. In the first 3 papers, I work with two rare fern species restricted to serpentine rocks, Asplenium adulterinum and A. cuneifolium, in a study system covering 10 × 10 km. I found that both species are long living (several decades) and in the study region, populations are in a good state and slowly growing. Even very small populations (10 individuals) have quite high chance to survive. In both fern species, I found dispersal limitation, which might be surprising regarding huge production of small spores in ferns (paper 2). The species differ in ploidy and thus, also mating system. A. adulterinum is tetraploid and its main breeding system is intragametophytic selfing. A. cuneifolium is...

Snapping turtles (Chelydra serpentina) are being harvested in unprecedented numbers in the United States (US) to meet the needs of international markets. Over three million live snapping turtles from farm and wild caught stock were exported from the US to Asia in 2012-14 alone. In the Commonwealth of Virginia, records indicate that 29,860 snapping turtles were commercially harvested between 2000 and 2015. Size limits are often used to regulate harvest pressure in snapping turtles and other game species. I analyzed the historic harvest of eleven US states to test the efficacy of minimum-size limit regulations at reducing commercial harvest pressure. Further, I conducted a four-year mark-recapture study on three Virginia waterways that have each experienced a different level of historic commercial harvest. As part of the larger mark/recapture project, I conducted radio telemetry on 23 turtles to examine seasonal, body size, and sex-specific effects on home range size of snapping turtles in a lotic system. I incorporated survival and growth rates from this study, demographic rates from the literature, and state-collected harvest rates into a hybrid age/stage population matrix model to estimate the population growth rate at three harvest levels (0%, 21%, 58%) that were estimated based on annual commercial landing reports on file with the Virginia Department of Game and Inland Fisheries. I used the model to test population viability under multiple size limit regulations, and used sensitivity analyses to identify adult stages most critical to the overall population growth rate. Based on model estimates, size-limits were effective at reducing harvest by 30-87% in years with high harvest pressure. However, most size limit regulations result in the removal of larger breeding adults, which has been shown to be detrimental to long term population viability. Based on radio-telemetry data, I found evidence that snapping turtles utilize lotic and lentic habitats differently, which can have implications for management of this iconic species. Matrix population modelling predicted that population densities at the moderate and high harvest site were reduced by 47% and 62%, respectively, when compared to the no harvest site. Model results indicate that, while an increase to the minimum-size limit in 2012 protected a larger portion of the population, that the commercial harvest of snapping turtles in the Commonwealth of Virginia is not sustainable under current state regulations. Our analysis suggests that minimum-size limits of 35.6 cm curved carapace length or greater will maintain viable populations by protecting a larger portion of reproducing snapping turtles within a population.

The sand lizard (Lacerta agilis) reaches the northern periphery of its distribution in south-central Sweden, where small, isolated relict populations occur in pine heath forests on sandy sediments. Modern forestry and fire suppression have reduced the amount of suitable open habitat for the species in this area and seem to be important for its decline. Main objectives of this thesis were to evaluate the efficiency of different management strategies, and if the sand lizard can function as an umbrella species for biodiversity conservation. Over a 16-year period, the estimated annual numbers of adult females in each of two study populations fluctuated between 23 and 3. Simulations of stochastic future population growth showed that the risk of extinction was highly dependent on population growth rate, which in turn was strongly affected by juvenile survival as indicated by elasticity analysis. Simulations of population growth for 50 years showed that the quasi-extinction risk (threshold ≤ 10 females) was > 56% for patches ≤ 1 ha; which is the observed average size of suitable habitat for inhabited patches during a 10-year period. In managed metapopulation networks with highly co-fluctuating local populations, among-population dispersal was not important to reduce extinction risks over a 50-year horizon. In the field the preferred microhabitat of sand lizards was successfully restored using tree felling and patch-soil scarification. The lizards gradually colonized the restored patches, and 16 years after restoration, sand lizards where mainly found there. Pine-heath area, and patch area within individual pine heaths, were of major importance for long-term population persistence at regional and landscape scales, respectively. Analyses of nested species subsets and an umbrella index suggest that the sand lizard can be a useful cross-taxonomic umbrella species on both scales for other red-listed species.

Eastern Sand Darter (Ammocrypta pellucida) is listed as Threatened under the Canadian Species at Risk Act. Canadian populations are declining primarily due to the siltation of sandy depositional areas, the preferred habitat of the species. Little other relevant biological information is available for most Canadian populations and only limited information is available for populations in the United States. To supplement the paucity of information, this study collected biological information on A. pellucida during field surveys in 2006- 2007 from 10 sites located around the Big Bend Conservation Area in the lower Thames River, Ontario, Canada. Collected data were used to estimate critical life history traits including: longevity, fecundity, clutch size and number, growth, survival, age-at-first-maturity and cohort age structure. Longevity was 3+ years, with age-at-first-maturity being 1+ for both sexes. A minimum of 2 clutches, were laid per year with an average clutch size of 71 eggs. Average density within in the study area was 0.36 ± 0.11 A. pellucida/m². Quantitative comparison of lower Thames River biological information with a more southerly A. pellucida population in the Little Muskingum River, Ohio, demonstrated little latitudinal variation between the populations. Data comparison suggests that localized environmental factors are affecting biological characteristics, in particular water temperature that may be controlled by differences in riparian cover and/or groundwater input. Field derived life history information was used to create a Leslie matrix model which was used for population viability analysis. Perturbation analyses of reproductive scenarios involving changes in clutch numbers and size and age-at-first maturity found large variations in the finite rate of population growth. Elasticity analyses further indicated that 0+ survival and 1+ fertility were the limiting life history parameters. Thus allowing fish to survive until first reproduction would have the largest overall impact on improving population viability. Inclusion of environmental stochasticity in the model facilitated estimation of extinction probabilities in the range of 0.13 to 0.21 within 100 years. Based on the above, it is recommended that management activities for protection and restoration of A. pellucida focus on habitat protection of nursery and spawning areas.

Eastern Sand Darter (Ammocrypta pellucida) is listed as Threatened under the Canadian Species at Risk Act. Canadian populations are declining primarily due to the siltation of sandy depositional areas, the preferred habitat of the species. Little other relevant biological information is available for most Canadian populations and only limited information is available for populations in the United States. To supplement the paucity of information, this study collected biological information on A. pellucida during field surveys in 2006- 2007 from 10 sites located around the Big Bend Conservation Area in the lower Thames River, Ontario, Canada. Collected data were used to estimate critical life history traits including: longevity, fecundity, clutch size and number, growth, survival, age-at-first-maturity and cohort age structure. Longevity was 3+ years, with age-at-first-maturity being 1+ for both sexes. A minimum of 2 clutches, were laid per year with an average clutch size of 71 eggs. Average density within in the study area was 0.36 ± 0.11 A. pellucida/m². Quantitative comparison of lower Thames River biological information with a more southerly A. pellucida population in the Little Muskingum River, Ohio, demonstrated little latitudinal variation between the populations. Data comparison suggests that localized environmental factors are affecting biological characteristics, in particular water temperature that may be controlled by differences in riparian cover and/or groundwater input. Field derived life history information was used to create a Leslie matrix model which was used for population viability analysis. Perturbation analyses of reproductive scenarios involving changes in clutch numbers and size and age-at-first maturity found large variations in the finite rate of population growth. Elasticity analyses further indicated that 0+ survival and 1+ fertility were the limiting life history parameters. Thus allowing fish to survive until first reproduction would have the largest overall impact on improving population viability. Inclusion of environmental stochasticity in the model facilitated estimation of extinction probabilities in the range of 0.13 to 0.21 within 100 years. Based on the above, it is recommended that management activities for protection and restoration of A. pellucida focus on habitat protection of nursery and spawning areas.

Of the seven pelican species found world wide, only the Great White Pelican (Pelecanus onocrotalus) and the Pink-backed Pelican (P. rufescens) are found in Africa. The KwaZulu-Natal province of South Africa supports only one breeding site for each of these species, and both sites represent the southern most breeding colonies for the two species in the eastern region of Africa. These nesting sites fall within the Greater St Lucia Wetland Park, and are afforded a degree of protection, but the same is not true for their foraging and dispersal ranges, and this is a cause for concern. Considerable amounts of data have been collected relating to the status, distribution and breeding efforts of these two species in north eastern KwaZulu-Natal. These data have been collected in a variety of ways by a large number of people. Part of this work represents an attempt to collate and summarise these data to produce an estimation of the status, distribution and breeding success of these species, and to evaluate any trends in their demography. For this south eastern region of Africa I estimated the population for the Great White Pelican to range between 6000 and 9000 individuals, and the Pink-backed Pelican to range between 600 and 900 individuals. Pelicans are highly mobile birds, and this allows them to move considerable distances when they forage, disperse or migrate. They are also long-lived birds with few natural predators. The two pelican species in south eastern Africa have been poorly studied and little is known about their movements, population dynamics and causes of mortality. Habitat change poses a potential threat to pelicans in north eastern KwaZulu-Natal, and habitat loss could drive these species out this region to areas north of South Africa. Much of this north eastern region of KwaZulu-Natal is under threat, mainly through the actions of man. Many areas are naturally unsuitable for pelican foraging, while others are vital to the survival of both species. This study includes an attempt to assess the movements of these two species in south eastern Africa, and to assess the relative importance and condition of the potential pelican habitat in the north eastern KwaZulu-Natal region, focusing particularly on Lake St Lucia and the Pongolo River floodplain. All this is necessary to produce a baseline from which long term predictions of potential pelican species survival can be made. In the absence of documented life tables and environmental variability data, a range of parameters was modelled to generate population viability analyses to simulate possible scenarios. These extinction models show the outcomes of both the deterministic and the stochastic processes. An attempt was also made to identify the factors that impact most severely on the persistence of these two species. The models were most sensitive to variation in survivorship in the first year of life and to the frequency of catastrophes. Changes in these parameters had the greatest effect on extinction risk. In January 2004 Lake St Lucia was reduced to a fraction of its normal capacity as a result of a severe drought in this region of KwaZulu-Natal. After rains in the area the lake level rose and then fluctuated considerably over the next 24 months. During this time the mouth of the estuary into the sea was closed. Great White Pelican numbers and lake levels were monitored throughout this period. This part of the study relates the changes in population numbers to the lake conditions, and highlights the importance of the lake to this avian species. It uses lake levels as a proxy for the conditions of wetlands in the Lake St Lucia region. It also addresses the implications of these relationships to the management strategy of the lake and the conservation of some avifauna. To identify conservation concerns for the Great White and Pink-backed Pelicans it was necessary to generate these baseline estimations. Although much of this information is uncertain for these two species, an attempt has been made here to predict the persistence of these species in north eastern KwaZulu-Natal and to highlight the conservation issues related to their future. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2006