Minke whales, Balaenoptera acutorostrata, are the most abundant species of mysticetes in the North Atlantic Ocean; however, little is known about their site fidelity and population size in the Northwest Atlantic Ocean. Field work was conducted off the coast of Halifax, Nova Scotia Canada, mostly during the summer months of 1997 to 2000 and 2002 to 2005 with some field seasons starting as early as April and ending as late as October. During 218 days of boat-based surveys, 614 photographs (black and white film and digital) of minke whales were collected. All photographs were assigned a qualitative quality value (Q1-Q4, best to poor, respectively), and 321 were assigned Q3 or better. A total of 111 individuals were identified, although only 80 individuals had at least one high quality photograph (Q3 and higher). While many individuals were re-identified on the same day, only five individuals were resighted on separate days. Two individuals were resighted within the same year (up to 90 days apart), and three individuals were resighted in separate years (a little over three years apart). Additional photographs collected opportunistically in 2007 yielded two additional resightings of the same individual sighted four years earlier. A discovery curve that failed to reach an asymptote indicated that new individuals continued to enter the study area, thereby classifying the study area as open. Using the POPAN module available in SOCPROG 2.3, abundance was estimated to be 454 individuals (Jackknife s.e. = 398) with an estimated mortality rate of 26% per year (Jackknife s.e. = 27%). It is likely that permanent emigration and mark-loss account for much of this estimated mortality rate. Continued long term photo-identification within the study area is required to improve the abundance estimate and properly assess the degree of site fidelity. A lack of site fidelity could signify either unreliable or low density prey distribution, a limited sample size or a much larger home range than the study area. Therefore, expansion of both the study area and field effort is recommended.

Holistic studies of mammalian life history factors and their consequences on population demography require an intensive, multifaceted field methodology and effort over long temporal scales. A 25-year longitudinal mark-recapture experiment on southern elephant seals, Mirounga leonina, at Subantarctic Marion Island provide such a foundation for demographic analyses and relevant methodology advancement. Two gaps in the methodology related to life history and population demographic research are, the absence of large samples of known mass individuals, and an inability to identify mother-pup relatedness. A novel three-dimensional photogrammetric technique is designed here that allows for mass estimation of large samples of southern elephant seals in the field. An effective temporary marking technique for unweaned pups is implemented that allows for identification of large samples of pups with known mothers prior to the maternal bond being severed at weaning. These known pups can then be marked with more robust tags and relatedness information is preserved long-term. Thus, mass estimates can now be applied as covariates in modelling analyses to address questions of, for example, maternal investment, kinship associated behaviour, and the consequences thereof on survival and reproductive parameters. The state change in the Marion Island southern elephant seal population from decrease to stabilisation/increase is shown to have resulted from improved survivorship in both juvenile and adult female age classes. Male seals of all ages did not indicate improved survivorship following the period of decline. The inflexion in survivorship is identified as 1994, whence improved survivorship of juvenile seals preceded that of young adult females. This inflexion in survivorship is postulated to have resulted in a population trend inflexion around 1998. Female southern elephant seals do not show evidence of actuarial senescence, but reproductive senescence is apparent after 12 years of age. A longterm reproductive cost (reduced breeding effort) is associated with early primiparity (age three) as compared with later primiparity (4- 5- or 6-year-old). The mean proportion of 3-year-old breeders has not increased after 1994 as has been hypothesized in previous studies. Contrary to previous assumptions, females do not as a rule breed every year. Annually interrupted breeding efforts are more common than consecutive breeding efforts. No difference in the proportions of interrupted versus uninterrupted breeding efforts was identified between periods of population decline and stabilisation/increase. Longevity as predicted by survival estimates exceeds the observed frequencies. This study provides unique longevity and fertility schedules for the species. The improved survivorship, reproductive senescence and breeding schedules of female southern elephant seals in this population provide groundwork for reevaluation of previous studies and their conclusions. The addition of relatedness and body condition information will allow for sophisticated multistate modelling of population demography in future studies. However, analytical procedures and techniques employed need to be meticulously designed and thoroughly thought through to avoid mis-interpretation of biological data. In addition to a multistate single species analytical approach, the importance of an ecosystem approach to species population demographic studies is highlighted through the augmenting of data on relevant potential drivers of population change, such as killer whales, Orcinus orca. / Thesis (PhD)--University of Pretoria, 2009. / Zoology and Entomology / unrestricted

Freshwater mussels (Unionidae) in the United States have experienced dramatic declines, and 25% species are listed as federally endangered. Hence, recovery plans for endangered species proposed a strategy of propagation of young mussels for release to natal rivers to augment declining populations. In this study, I conducted laboratory experiments, assessed site suitability for mussel restoration, and evaluated survival and growth rates of released mussels to meet the requirements of recovery plan. I conducted multiple experiments to develop an improved protocol for juvenile mussel propagation and culture. Significantly greater survival and growth rates were found in newly metamorphosed juveniles of the rainbow mussel (Villosa iris) reared in a substrate of fine sediment and one-month-old juveniles of wavy-rayed lampmussel (Lampsilis fasciola) fed on natural food in pond water. Bio-filter media greatly increased water quality by reducing the concentration of ammonia and nitrite. The negative impacts of flatworm predation and filamentous algae in juvenile culture were controlled, and juvenile escapement was prevented. Juvenile mussels were successfully produced and cultured to stockable size (>15 mm) for release. I released laboratory-propagated mussels at three historically important sites in Clinch and Powell rivers for the assessment of site suitability. Use of cages was the most effective method to determine site suitability because the free-released mussels (untagged, tagged) had low catchability. Mussels released at Horton Ford, Clinch River, exhibited significantly faster growth. Horton Ford is the most suitable site, while environmental conditions at Fugate Ford, Powell River, are deemed unsuitable for mussel restoration and recovery. To facilitate the detection of released mussels, I applied Passive Integrated Transponder tags to laboratory-produced juveniles of the endangered Cumberlandian combshell (Epioblasma brevidens) and released them near Brooks Bridge, Powell River. The detection probability increased above 98%. I developed a set of hierarchical Bayesian models incorporating individual variations, seasonal variations, periodic growth stages and growth cessation to estimate survival, detection probability and growth of released mussels in a changing environment. Mussels of E. brevidens exhibited great survival (> 99% per month) and growth, indicating suitable conditions for recovery of this endangered species at this site. / Ph. D.

Prior to European settlement, black bear (Ursus americanus) were far less abundant in the state of California. Estimates from statewide harvest data indicate the California black bear population has tripled in the last 3 decades. Bears inhabit areas they formally never occurred (e.g., urban environments) and populations that were at historically low densities are now at high densities. Though harvest data are useful and widely used as an index for black bear population size and population demographics statewide, it lacks the ability to produce precise estimates of abundance and density at local scales or account for the numerous bears living in non-hunted areas. As the human population continues to expand into wildlife habitat, we are being forced to confront controversial issues about wildlife management and conservation. Habituated bears living in non-hunted, urban areas have been and continue to be a major concern for wildlife managers and the general public. My objective was to develop DNA-based capture-mark-recapture (CMR) survey techniques in wildland and urban environments in Mono County, California to acquire population size and density at local scales from 2010 to 2012. I also compared population density between the urban and wildland environment. To my knowledge, DNA-based CMR surveys for bears have only been implemented in wildland or rural environments. I made numerous modifications to the techniques used during wildland DNA-based CMR surveys to survey bears in an urban environment. I used a higher density of hair-snares than typically used in wildland studies, non-consumable lures, modified hair-snares for public safety, included the public throughout the entire process, and surveyed in the urban-wildland interface as well as the city center. These methods were efficient and accurate while maintaining human safety. I determined that there is likely a difference in population density between the urban and wildland environments. Population density was 1.6 to 2.5 times higher in the urban study area compared to the wildland study area. Considering the negative impacts urban environments can have on wildland bear populations, this is a serious management concern. The densities I found were similar to those found in other urban and wildland black bear populations. The baseline data acquired from this study can be used as part of a long-term monitoring effort. By surveying additional years, population vital rates such as apparent survival, recruitment, movement, and finite rate of population change can be estimated.

No description available.

I conducted demographic and behavioral studies of Western Sandpipers (Calidris mauri) breeding on the Yukon-Kuskokwim River Delta, Alaska (1998-2005). In chapter one, I estimated apparent annual survival (product of true survival and site fidelity) while correcting for the probability of encounter for 237 males and 296 females. Overall return rates (individual returned to the site in a subsequent season) were lower for females (40%) than males (65%), as was apparent annual survival (± SE, females = 0.65 ± 0.05, males = 0.78 ± 0.03), and encounter rate (females = 0.51 ± 0.07, males = 0.74 ± 0.04). In chapter two, I examined the effects of mate and site fidelity on nesting success (N = 430 nests). Annual divorce rate ranged between 37-83%, with 17-63% of pairs reuniting annually. Reuniting pairs initiated clutches earlier than newly formed pairs, and clutches that were initiated early in the season had higher nest success rates compared to late-season nests. When I controlled for clutch-initiation date, nests tended by individuals with prior breeding-site experience had higher daily survival rates compared to birds breeding at the site for the first time. The effect of site experience was greater for males than females. In chapter 3, I reported that Western Sandpipers exhibited aggregated breeding behavior on a 36 ha plot. Breeding aggregations occurred when dominant and/or older individuals excluded younger, subordinate individuals from preferred habitat. The pattern of habitat occupancy conformed to an ideal despotic distribution with aggregated nesting birds in less preferred habitat experiencing lower reproductive success. In chapter 4, I described and demonstrated the form and function of parent-chick communication in the Western Sandpiper. Through experimental playback of adult vocalizations to chicks in the field, I demonstrated: (1) chicks respond to the alarm call by vocalizing relatively less often and moving away from the signal source, (2) chicks respond to the gather call by vocalizing relatively more often and moving toward the signal source, (3) and chicks respond to the freeze call by vocalizing relatively less often and crouching motionless on the substrate for extended periods of time. I also describe two distinct chick vocalizations (chick-contact and chick-alarm calls). / Ph. D.

The Staunton River is a high gradient, second order stream approximately 6 km in length located on the eastern slope of the Blue Ridge Mountains in Shenandoah National Park, VA. In June 1995, a catastrophic flood and debris flow altered the instream habitat and <i>Salvelinus fontinalis</i> population of the Staunton River. The debris flow scoured the streambed, deposited new substrate materials, removed trees from the riparian zone, and eliminated fish from a 1.9km section of the stream. By June 1998, both young-of-year (YOY) and age 1+ <i>S. fontinalis</i> had recolonized the debris flow affected area. The event provided a rare opportunity to examine recovery of the <i>S. fontinalis</i> population and instream habitat in addition to addressing potential effects of the debris flow on movement, activity, and growth of fish in the debris flow affected and unaffected areas of the stream. Post-recolonization movement and activity were monitored using two-way fish traps (weirs), mark-recapture techniques, and radio telemetry. The weirs failed to produce any movement data. Most fish (91%) in the mark-recapture study had range sizes less than 100m, however biases common to mark-recapture study designs (low recapture rate, flawed logic, etc.) hampered interpretation of results. For example, subsequent recapture of individually marked fish indicated that as many as 54% of marked fish confirmed to have been alive at the time of a recapture session were not recaptured. Radio telemetry provided information on <i>S. fontinalis</i> movement and activity at seasonal and diel scales during summer and fall. Differences in movement and activity between the debris flow affected and unaffected areas were minimal when compared to seasonal variations. During summer, range sizes were near 0m and crepuscular activity patterns were observed. During the fall range size increased and diel activity was concentrated in the mid-afternoon with a much higher peak than during summer. Basin-wide visual estimation technique (BVET) fish population surveys performed each spring and fall from 1993 = 1999 provided pre- and post-event fish population abundance and density estimates. Post-event fish growth in the debris flow affected and unaffected areas was monitored using mark-recapture techniques. Abundance and density of both YOY and age 1+ <i>S. fontinalis</i> exceeded pre-event levels within 2-3 years. Growth of YOY and age 1+ fish was significantly greater in the debris flow affected area until spring 1999. Population density appeared to have a strong negative influence on growth. The observed changes in fish growth and differences in fish size associated with population density would be of minimal importance to the typical angler but may suggest a mechanism by which <i>S. fontinalis</i> populations can quickly recover from catastrophic events. BVET habitat surveys provided information on total stream area, number of pools and riffles, pool and riffle surface area and depth, substrate composition, and large woody debris (LWD) before (1993), immediately following (1995), and four years post-event (1999). Immediately following the debris flow, the stream channel was highly disordered which resulted in an increase in the total number of habitat units and a decrease in average habitat unit surface area, total stream area, and average depth when compared with pre-event conditions. In addition, substrate composition had shifted from small to large diameter particles and LWD loading had increased in both debris flow affected and unaffected areas. Four years after the event, the total number of habitat units, average habitat unit surface area, total stream area, and average depth had all returned to near pre-debris flow levels and substrate composition had begun to shift towards smaller particle sizes. Changes in LWD loading from 1995-1999 reflected changes in the riparian zone following the debris flow. In the unaffected area, where riparian trees remained intact, LWD loading increased, whereas in the debris flow affected area, where riparian trees were eliminated, LWD loading decreased. For the most part the effects of the debris flow, although immediately dramatic, were in the long term minimal. The debris flow affected area was recolonized rapidly and abundance and density quickly rebounded past pre-event levels. Differences in fish growth between the affected and unaffected area were short lived. Any effect the debris flow affected area may have had on movement or activity was minimal when compared with seasonal variations. Most habitat characteristics reverted to near pre-event levels just four years after the flood and debris flow. Although a number of factors will influence recovery time from such events, these results indicate that immediate management action, such as stocking or habitat modifications, are not necessary in all cases. / Master of Science

The evolution of extra-group paternity (EGP) is a contentious issue in evolutionary biology. This thesis examines the factors and adaptive benefits driving EGP in a high-density, group-living population of European badgers (Meles meles). To improve power to assign parentage, I isolated and characterised 21 new polymorphic microsatellite markers. I genotyped 83% of 1410 badger trapped 1987‒2010 using 35 autosomal microsatellite markers. Maternity and paternity were assigned at 80% confidence ca. 82% of individuals. 48% of paternities were extra-group, where 85% were attributable to neighbouring-group males and EGP was detected in 47% of litters; thus badger social group do not correspond with a breeding unit. I tested whether indirect genetic benefits explain these high EGP rates. (1) ‘Good-gene-as-heterozygosity Hypothesis’: Paternal heterozygosity, but not maternal or an individual’s own heterozygosity, associated positively with first-year survival probability. Under benign environmental conditions, cubs fathered by more heterozygous males had a higher first year survival probability. Despite this correlation, the EGP rate per litter correlated with neither average nor maximum within-group heterozygosity of candidate fathers. (2) Fitness benefit Hypothesis: Extra-group offspring (EGO) had lower first-year survival probability and lived 1.3 years less than within-group offspring (WGO). Female WGO produced more litters and offspring over their lifetime than female EGO, whereas male EGO produced more offspring than male WGO. (3) Inbreeding avoidance hypothesis: The EGP rate within a litter increased with greater average pair-wise relatedness between mothers and within-group candidate fathers. No inbreeding depression on first-year survival probability was detected, but small sample sizes limited statistical power. Socio-ecologically, at the litter level, EGP correlated negatively with the number of within-group candidate fathers, and positively with neighbouring-group candidate fathers. In conclusion, EGP in badgers may reduce inbreeding and be maintained in the population through a sex-specific antagonistic selection and indirect genetic benefits may occur when the total fitness benefits of producing extra-group sons outweigh the costs of producing extra-group daughters. These indirect genetic benefits only partially explain the evolution of promiscuity in European badgers, highlighting that evolutionary factors underlying promiscuity remain unclear.

New analytical and technological tools have the potential to yield unprecedented insights into the life histories of migratory species. I used Bayesian population models and Global Positioning System-acceleration tracking devices to understand the demographic mechanism and likely drivers underpinning the Greenland White-fronted Goose (Anser albifrons flavirostris) population decline. I used a 27-year capture-mark-recapture dataset from the main wintering site for these birds (Wexford, Ireland) to construct multistate models that estimated age- and sex-specific survival and movement probabilities and found no sex-bias in emigration or ‘remigration’ rates (chapter 2). These formed the foundation for an integrated population model, which included population size and productivity data to assess source-sink dynamics through estimation of age-, site-, and year-specific survival and movement probabilities, the results of which suggest that Wexford is a large sink and that a reduction in productivity (measured as recruitment rate) is the proximate demographic mechanism behind the population decline (chapter 3). Low productivity may be due to environmental conditions on breeding areas in west Greenland, whereby birds bred at youngest ages when conditions were favourable during adulthood and the breeding year (chapter 4), and possibly mediated by links with the social system, as birds remained with parents into adulthood, forfeiting immediate reproductive success, although a cost-benefit model showed the ‘leave’ strategy was marginally favoured over the ‘stay’ strategy at all ages (chapter 5). Foraging during spring does not appear to limit breeding, as breeding and non-breeding birds did not differ in their proportion of time feeding or energy expenditure (chapter 6). Two successful breeding birds were the only tagged individuals (of 15) to even attempt to nest, suggesting low breeding propensity has contributed to low productivity. Although birds wintering in Ireland migrated further to breeding areas than those wintering in Scotland, there were no differences in feeding between groups during spring migration (chapter 7). These findings suggest that Greenland White-fronted Geese are not limited until arrival on breeding areas and the increasingly poor environmental conditions there (chapter 8). More broadly, these findings demonstrate the application of novel tools to diagnose the cause of population decline.

Chez les espèces longévives, une relation inverse entre la variabilité des paramètres démographiques et leur élasticité (i.e. la contribution relative du paramètre au taux de croissance de la population) semble exister. La théorie de la canalisation environnementale permet d'expliquer une telle relation. Les paramètres ayant la plus haute élasticité auraient évolué de façon à être moins variable face aux variations environnementales afin d'optimiser la fitness individuelle et ainsi maximiser la croissance de la population. Afin de tester l'existence d'une telle hypothèse chez une espèce, il est nécessaire d'estimer les paramètres démographiques ainsi que leur contribution relative au taux de croissance. À l'aide des modèles les plus récents de capture-marquage-recapture, nous avons donc estimé les paramètres de survie juvénile et de reproduction chez la grande oie des neiges pour les comparer au taux de survie adulte, paramètre le plus élastique.Notre étude a montré que les paramètres de survie juvéniles et de probabilité de nicher étaient très variables, tel qu'attendu. Le taux de survie juvénile dépend des conditions environnementales, avec notamment un fort effet du parasitisme. En vermifugeant des individus, nous avons trouvé un effet négatif des parasites intestinaux sur la survie des oies juvéniles femelles mais pas sur celle des mâles, ce qui s'explique probablement par une différence d'investissement dans le système immunitaire en fonction du sexe chez les individus en croissance. La probabilité de nicher est également dépendante des conditions environnementales mais notre étude a également révélé l'existence de coûts associés à la reproduction. En effet, la probabilité de nicher l'année suivante était fortement réduite suite à une reproduction avec succès comparé aux individus qui avaient eu un échec. Par contre, parmi les individus qui nichent, ceux qui avaient du succès l'année précédente avaient plus de chance d'avoir à nouveau du succès l'année suivante que ceux qui avaient eu un échec, ce qui suggère une hétérogénéité dans la qualité des individus. En parallèle de ces estimations, nous avons montré que le taux de survie adulte était constant au cours du temps et indépendante du statut reproducteur l'année précédente. Finalement, nous avons également trouvé que la survie adulte ne différait pas entre 2 colonies situés à 800 km de distance dans l'Arctique canadien, ce qui suggère une absence de variabilité spatiale pour ce paramètre démographique. Notre étude a donc démontré la faible variabilité temporelle et spatiale du paramètre démographique le plus important pour le taux de croissance de la population, contrairement aux autres paramètres qui montrent une forte variabilité chez la grande oie des neiges. Notre étude permet donc d'appuyer la théorie de la canalisation environnementale des paramètres démographiques chez les espèces longévives. / In long-lived species, an inverse relationship apparently occurs between variability of demographic parameters and their elasticity (i.e. the relative contribution of a given parameter to the population growth rate). The environmental canalization theory has been proposed to explain such a relationship. Demographic parameters with the highest elasticity should have evolved in a way reducing their variability in presence of environmental variations in order to optimize individual fitness and hence to maximize the population growth rate.To test this hypothesis in a given species, demographic parameters and their elasticity need to be accurately estimated. Using advanced capture-mark-recapture models, we estimated juvenile survival and breeding probabilities in the greater snow goose and we compared their variability to adult survival, the parameter with the highest elasticity.Our study showed that both juvenile survival rate and breeding propensity were highly variable, as expected. The juvenile survival probability varied upon environmental conditions, with a strong impact of parasitism. An anthelmintic drug treatment applied to juveniles revealed a negative effect of intestinal parasites on survival of juvenile females but not males, which could be explained by a sex-differential investment in the immune system in growing individuals. We found that the breeding propensity also varied with environmental conditions but we also found some evidence for costs of reproduction. Breeding propensity in the following year was greatly reduced after a successful reproduction compared to birds that had a failed attempt. However, among birds that bred, those that had a success the year before were more likely to be successful again the following year than those that had failed, which suggests heterogeneity in individual quality. In those studies, we showed that adult survival was constant over time and independent of the breeding status the year before. Finally, we also found that adult survival did not differ between 2 breeding colonies distant of 800 km in the Canadian Arctic, which suggests an absence of spatial variability for this demographic parameter.We thus demonstrated a low temporal and spatial variability in the most important demographic parameter for population growth, which contrasts with the high variability of other parameters in the greater snow goose. Our study supports the environmental canalization theory as applied to demographic parameters in long-lived species.