The blue shark (Prionace glauca) is among the most abundant and widely distributed of all oceanic elasmobranchs. Millions of blue sharks are caught annually worldwide in pelagic long line fisheries, and it accounts for the largest component of auctioned fin weight in the international shark fin trade. There is growing concern about the depletion of its populations worldwide and impacts of such large scale removal of an apex predator on oceanic ecosystem stability. The fragmentary nature of life history information available for blue sharks, including on its detailed movement and migratory behavior, continues to limit management efforts that require such data for stock assessment and sustainable catch modeling. To assist in obtaining a better understanding of blue shark movement behavior in the western north Atlantic, I used satellite telemetry to investigate the detailed habitat utilization and movements of sharks during the summer months when the sharks form aggregations on the continental shelf off the Northeast United States, and during their fall , pelagic migrations. Thirty-one (26 male, 5 female) blue sharks were tagged with pop-up archival satellite transmitters. The transmitters reported data from a total of 1,656 combined days, yielding 74,163 depth recordings and 74,125 temperature recordings. Tracked sharks exhibited two distinct movement patterns: During the summer months, the sharks remained within a restricted geographical area south of Nantucket Island and spent nearly 80% of their time in the uppermost part of the water column in <20 m depth (mean depth of 8 m). During fall months (October and November) the sharks made fairly directed offshore and southerly movements, with several sharks associating with waters east of Bermuda. During their pelagic migrations, the sharks demonstrated markedly different water column utilization behavior. They occupied much greater depths (127 m mean depth) and exhibited a clear diel depth pattern, occupying deeper water during the day and shallower water at night, not observed on the shelf. The longest duration track was that of an immature female for nine months. The greatest distance traveled was by a mature male that moved from Martha's Vineyard, MA to waters near Puerto Rico (a linear distance > 4,000 km). There was some indication that the different demographic groups (mature males, immature males, and immature females) may display different movement behavior, especially during their pelagic migrations. This study provides the first detailed information on habitat utilization and movement patterns of blue sharks in the Western North Atlantic, and points to the need for further investigation of movement behavior by different demographic segments of the population.

Great barracuda Sphyraena barracuda is a large predatory teleost found circumglobally, other than the Eastern Pacific Ocean. The species is commonly caught by both recreational and commercial fishermen as bycatch while targeting other, more economically or recreationally valuable fishes. This species also exhibits an ontogenetic shift in habitat, with juveniles inhabiting mangrove and seagrass habitats, while adults live near offshore reefs and associated structure. This thesis consists of two separate studies of S. barracuda: 1) feeding ecology along an ontogenetic gradient and 2) habitat utilization of as derived through electronic tagging. The first chapter of this thesis describes the feeding ecology of great barracuda in South Florida, with an emphasis on the determination of when the ontogenetic shift in diet occurs between habitats and individual fish sizes. Specimens were collected primarily by seine net and hook-and-line fishing. The specimens were then dissected with the stomach contents examined. This study found that the ontogenetic diet shift in great barracuda begins around the second year, and that juveniles and adults are opportunistic predators with a wide diversity of teleost and crustacean prey items within the selected habitat. The second chapter of this thesis describes the habitat utilization and vertical movements of two great barracuda off of South Florida interpreted from data acquired from pop-up satellite archival tags (PSATs). This study found that large (>100 cm) great barracuda are capable of travelling hundreds of kilometers over a period of days to weeks. The results show that large great barracuda can tolerate temperatures ranging from 17.8° C to 31.3° C, and are capable of diving to depths greater than 175 m. It was also found that there was a significant difference in time spent at depth, with greater depths being inhabited more frequently at night.

A study of the Merriam's wild turkey was conducted March 1972 to August 1973 in southwestern Utah to determine the life history and habitat utilization. Using transects, bio-telemetry, and observational techniques, information on flocking, hen:poult and sex ratios, and approximate dates for spring dispersal, nesting, and hatching was obtained. Turkey observations in relation to habitat variables were used to determine habitat utilization. Except during the spring mating season, male flocks remained apart from other turkeys. Hen flocks in fall and winter consisted of adult hens and juveniles of both sexes. Males dispersed from winter flocks in March, and those that became harem gobblers attracted not more than 3 hens. Egg-laying probably took place from mid-April to mid-May and hatching from mid-May to mid-June. A drop in hen:poult ratios from 1:2.2 in 1972 to 1:0.7 in 1973 was attributed to harsh spring weather. Hens comprised an estimated 60 percent of the population during the study period. Turkeys utilized a faU-winter-early spring habitat of mountain brush and scattered ponderosa pine. Late spring use was associated with a ponderosa pine or aspen-mixed-conifer habitat type. Broods highly used glades dominated by an aspen overstory with intermingling mixed-conifer, while a male flock used mixedconifer clearings at 10,000 feet elevation. The upper and lower limits of turkey range on the study area were 10,000 and 6,000 feet, respectively. Turkeys began spring migration in April and fall migration in late September or early October.

The conservation biology field seeks to preserve biodiversity and the processes shaping that variation. Conservation biology is intimately tied to evolutionary research, in order to identify evolutionary distinct lineages that may be in danger of disappearing. Interestingly, patterns and processes of lineage divergence and persistence change with respect to spatial and temporal scale. I seek to evaluate biodiversity, the factors that have shaped this heterogeneity, and how this variability persists. To accomplish this I used a phylogeographic approach as well as niche and population modeling on the Peromyscus maniculatus species group found widely distributed in North America. My emphasis was on the southeastern U.S. species P. polionotus and its distinct beach forms. At a continental scale, I found that environmental niches are likely involved in generating and/or maintaining genetic lineages within the P. maniculatus species group. These findings add to a growing number of studies that have identified lineages occupying different environmental spaces. At a regional scale, I supported the hypothesis that barrier islands on the Atlantic coast of Florida were colonized by an ancestral form of P. polionotus by a single colonization, from the central Florida area. Subsequently, at least two distinct lineages diverged (P. p. phasma and P. p. niveiventris). I also found evidence that suggests that the extinct form of beach mouse (P. p. decoloratus) is part of the P. p. phasma lineage. At the population level, I evaluated changes in genetic diversity in historical samples compared to those that experienced recent human encroachment on natural habitat I used tissue preserved in natural history collections to compare with live-trapped specimens, and found that P. p. niveiventris has maintained historical genetic diversity levels. I suggest that the continuation of historical levels of genetic diversity is due to the presence of a single large area iv of continuous habitat in the central portion of the species’ current distribution. Finally, I evaluated the importance of scrub and beach habitat to the population dynamics of beach mice. Beach mice have traditionally have been associated with beach dunes rather than with the scrub habitat found more inland on barrier islands. Using almost three years of capture-recapture data from Cape Canaveral Air Force Station (CCAFS), I created a stochastic matrix model to assess the relative contribution of populations from the two different habitats to a variety of demographic measures. Both field data and model results provided evidence that the population dynamics of beach mice may rely much more on scrub habitat than formerly documented. Overall, my research emphasized a hierarchical approach to evaluate biodiversity and the processes shaping differentiation at different spatial and temporal scales. The methods and findings give insight into speciation at different scales, and can be applied to a wide range of taxa for questions related to evolutionary and conservation biology.

Made available in DSpace on 2015-03-05T16:19:35Z (GMT). No. of bitstreams: 0 Previous issue date: 12 / Nenhuma / Os mamíferos de médio e grande porte distribuem-se em todos ecossistemas mundiais, possuindo grande importância ecológica, pois contribuem para a manutenção do equilíbrio das comunidades. Sua diversidade atual na Mata Atlântica, e especificamente, na Floresta de Araucária (FO) do Sul é alta. Contudo, devido ao grande valor econômico da araucária, espécie dominante na FO, esse ambiente foi intensamente fragmentado e grandes áreas substituídas por plantações arbóreas, exóticas e nativas. O objetivo deste estudo foi investigar como a mastofauna de médio e grande porte utiliza um mosaico florestal, formado por Floresta Ombrófila Mista e plantações de pinus, eucalipto e araucária, em área de Floresta Nacional. Localizada em São Francisco de Paula, RS. Para a coleta de dados utilizei armadilhas de pegadas, dispostas em todos os hábitats formando grades de captura (9 armadilhas por grade, 0,64 ha de área total), com três grades (repetições) por hábitat. Nessas armadilhas utilizei atrativos do tipo, banan / Medium and large mammals occur in all world ecosystems. Their ecological role is very important, since they contribute for the maintenance of the equilibrium of their communities. The mammal diversity in the Atlantic forest and, specifically, in the Araucaria Forest (FO) of southern Brazil is very high. However, mainly due to the high value of Araucaria angustifolia (the dominant species of the FO) as timber, this forest formation has been intensely fragmented, with large areas being replaced by arboreal plantations of both introduced and native species. In this study we investigated how the medium and large-sized mammalian fauna uses a forest mosaic composed of patches of MOF and plantations of Pinus spp., Eucalyptus sp., and also A. angustifolia. For data collection I used trapping grids of sand track stations placed in all habitats (9 stations per grid, total area of 0.64 ha), with three grids (replicates) for each habitat. In this stations I used three bait types: banana, bacon and Pipdog. I es

The use of pop-up satellite archival tags (PSATs) eliminates many of the limitations associated with acoustic and conventional tags by using fishery-independent data collection and retrieval. Previous research techniques have provided information on longer-term movements, migrations, and behavior patterns, but there is still a need for additional tagging studies using tags with depth and light data and increased memory that will further define the short-duration activity patterns and habitat utilization of juvenile swordfish in the western North Atlantic. PSATs have been successfully used on other large pelagic fishes, but have yet to be used on juvenile swordfish. This study investigated two main topics: a) the post-release survival rates of juvenile swordfish after being released from the recreational rod-and-reel fishery and commercial swordfish buoy gear fishery in the Florida Straits, and b) the habitat utilization of juvenile swordfish following release. High-resolution PSAT technology was used to estimate the post-release survival of 16 individual juvenile swordfish captured with standard recreational or buoy fishing gear and techniques in the southeast Florida swordfish fishery. Analysis of release mortality estimates was done using the “Release Mortality” Program. Five of the fourteen reporting tags showed a mortality within 48 hours, for a release mortality rate of 35.7%. However, no common thread could be found among the five mortalities. Results of the Release Mortality program indicated that if the true mortality rate was 35.7%, approximately 1800 tags would have to be deployed to increase the precision of the mortality estimates to +/- 5% of the true value. The nine surviving fish varied in straight-line distance traveled and in direction, and could withstand a wide range of temperatures. A deterministic, periodic model was developed to fit to the data and describe the fishes’ habitat utilization. This model identified both diurnal and lunar signals in the data, confirming that juveniles do move vertically based on the daily cycle of the sun and the lunar cycle of the moon and that their diurnal movements are much greater than their lunar movements. The results of this study can be valuable to management practices in future stock assessments and decisions regarding mandatory release of undersized fish.

Unregulated North Swedish rivers show large seasonal variations in their physical characteristics. During winter the whole littoral zone freezes solid, and in spring the water flow increases rapidly and the same areas become flooded. The two mayflies Parameletus chelifer and P. minor are common in the North Swedish river Vindelälven. They probably pass through a dormant egg stage in its mid-stream section. The first tiny nymphs appeared in January to March, but they did not become abundant until the ice broke up in May. At this time they migrated rapidly to the flooded upper littoral, some continuing into the tributaries. During  the migration phase, both species used chemoreception to orient themselves towards the flooded areas. The shoreward migration allowed the nymphs to avoid high current velocity, and to utilize unexploited food resources. The two species differed with respect to utilization of the upper littoral. Most Parameletus chelifer nymphs colo­nized a seasonal stream, while the P. minor nymphs were equally abundant at the river margin as in a seasonal stream. Both temperature and food quality differed between the river margin and the seasonal stream. Compared to P. minor specimens, those of Parameletus chelifer showed a somewhat higher optimum tempe­rature, and they gained advantage of the higher food quality observed in the seasonal stream. Parameletus chelifer specimens colonizing a seasonal stream had higher growth rate, higher fecundity, and probably also advanced emergence as well as larger adult size compared with those remaining at the river margin. In addition mortality from fish predation may be lowered by utilizing shallow seasonal streams. Specimens of P. minor had higher growth rate, larger adult size and advanced emergence in the seasonal stream compared with those at the river margin. Nevertheless, fecundity was equal in both habitats and the mortality caused by predation seemed almost similar in both habitats. In most years Parameletus chelifer specimens utilizing the seasonal stream thus obtain a higher fitness than those utilizing the river margin. In P. minor this diffe­rence was not so pronounced. However, due to mortality risks caused by an early desiccation of the seasonal stream, the long-term reproductive output of the two species probably varies irregularly in the two habitats. / digitalisering@umu

The cross-sectional form of semi-alluvial bedrock channels was investigated. Channel geometry data were collected from a variety of streams in Ontario and Québec, Canada to develop empirical downstream scaling relationships. The relationships revealed that bedrock, mixed, and alluvial channels scale at similar rates with respect to discharge. The widest channels were formed in low-relief sedimentary bedrock with minimal alluvial cover. Channels influenced by resistant igneous/metamorphic bedrock produced a strong scaling relationship, whereas channels influenced by weak sedimentary bedrock produced a weak scaling relationship. Alluvial cover appeared to exhibit more control on channel width in low-relief settings in comparison to high-relief settings, with increased alluvial cover promoting channel narrowing. Channels influenced by igneous/metamorphic bedrock produced identifiable thalwegs, presumably due to well-defined bedload transport pathways. Channels influenced by sedimentary bedrock tended to have planar beds. Additionally, fish habitat was investigated at one semi-alluvial bedrock stream in Ontario, Canada. Fish sampling was conducted at proximate bedrock and alluvial sections followed by a survey of physical habitat parameters to evaluate habitat preferences. Adult logperch (Percina caprodes), juvenile white sucker (Catostomus commersonii), adult round goby (Neogobius melanostomus), and adult longnose dace (Rhinichthys cataractae) demonstrated preference toward alluvial substrate, whereas juvenile logperch and adult banded killifish (Fundulus diaphanus) demonstrated preference toward bedrock. Juvenile silver shiner (Notropis photogenis) and juvenile yellow perch (Perca flavescens) were indifferent to substrate type. Empirical depth and flow velocity habitat suitability indices (HSIs) were developed for each fish species. This study presents the first fish habitat suitability criteria developed from a small semi-alluvial bedrock stream and may provide valuable information for fisheries management endeavours in such environments.

The main aim of this study was to classify and describe the plant communities in the home range of white rhinoceros in order to understand the animal seasonal foraging ecology. To provide a detailed habitat description, forty sample plots were stratified randomly. A TWINSPAN classification, refined by Braun-Blanquet procedures, was carried out on the Viewpoint section of the reserve. Ten plant communities, grouped into five major community types, were identified. The veld condition and ecological carrying capacity in these communities were measured, stating an abundance of food on long grass while the short grass equal the number of short grass feeders. A number of behavioural aspects such as activity data, home range utilization and dietary usage were examined. Statistical methods such as the Spearman rank-order correlation, Wilcoxon sign test and Student T-test were used on rhino data. The difference in usage of the home range during wet and dry seasons was insignificant. / Environmental Sciences / M.Sc. (Environmental Management)

Thesis (PhD) -- Stellenbosch University, 1990. / ENGLISH ABSTRACT:Bushpig sociology, energetics, reproduction and population dynamics were studied over an 8-year period in the Cape Province, South Africa. The social organization was found to be strikingly different from that known from other suid species. The basic social unit is a unimaternal family group, occupying a resource-based territority, with a monogamous mating system. This form of social organisation is related to the dispersed nature of food resources, to which it provides exclusive access. It is reminiscent of canid social systems. Agonistic behaviour, communication and maternal behaviour were studied as the opportunity arose. The average home range size was 7,2 kmª, ranging from 3,8 to 10.1 kmª. Home ranges were often traversed within 1-4 days, as part of territory patrolling. The average diel ranging distance was 3 km. Bushpig were active during both night and day and exhibited a basic bimodal rhythm. The main phase of intensive foraging occurred from before dusk to midnight, with a secondary activity peak after dawn. Activity schedules were geared to avoid extreme ambient temperatures. Temperature regulation and water use were investigated, with particular reference to thermoregulatory behaviour (nest building). pelage characteristics, body core temperature dynamics, thermoneutral zones and resting metabolic rates. The thermoneutral zone for 10 kg bushpig juveniles was estimated to lie between 13° and 30°C and that for adults between 8° and 25°C. Foraging behaviour, diet and its nutritient content were investigated. Regional differences in the nutritional quality of bushpig diets in the Eastern and Southern Cape were associated with the predominance of nutrient-rich and nutrient-poor substrates respectively. These in turn were reflected by divergent life history features in the populations from the two regions. Patterns of growth and energy storage were described and the value of various parameters (e.g. mass to size ratio, fat depositions, blood composition) to evaluate condition was investigated. In studying reproductive biology, sexual maturation, female reproductive cycles, prenatal litter statistics, foetal development, 1actation, breeding seasonality and reproductive turnover were the main aspects addressed. The role of food quality, body condition and social status in determining reproductive success was discussed. Bushpig population density estimates in the Southern Cape ranged between 0,3 and 0,5 animals/kmª• The dynamics of Southern and Eastern Cape populations were found to differ. The differences are consistent with the hypothesis that social organisation is determined by the distribution and availability of food while diet quality shapes life history tactics. A life history model was developed which links edaphoclimatic environmental conditions with diet quality, metabolic turnover rate and, ultimately, life history features. In the concluding chapter some of the managerial implications of the research findings are discussed. / AFRIKAANSE OPSOMMING:Die sosiologie, fasette van die energiebalans (temperatuurregulasie, voeding). voortplanting en bevolkingsdinamika van bosvarke is in die Kaapprovinsie (Suid-Afrika) oor 'n tydperk van 8 jaar bestudeer. Dit kon bewys word dat die sosiale organisasie van die bosvark van die van ander varksoorte verskil. Die basiese sosiale eenheid bestaan uit 'n familiegroep wat slegs 'n enkele telende moederdier bevat. Ruimtelike organisasie is gebaseer op 'n stelstel van voedingsterritoriums. 'n Monogamiese paringstelsel kom voor. Die yl verspreiding van voedsel word as die onderliggende rede vir die sosiale organisasie beskou. Gedragspatrone (kommunikasie, aggressie, grootmaak van kleintjies) is bestudeer soos die geleentheid voorgekom het. Heelwat ooreenkomste is gevind tussen die sosiale organisasie van die bosvark en lede van die hondefamilie. Die gemiddelde woongebiedgrootte is 7,2 kmª (tussen 3,8 en 10,1 kmª). Woongebiede word gewoonlik binne 1-4 dae deurkruis en dus soos territoria gepatroleer. Die gemiddelde daaglike bewegingsafstand was 3 km. Bosvarke was beide gedurende die nag en die dag aktief en het 'n bimodale aktiwiteitsritme gevolg. Die hoofaktiwiteitsfase van intensiewe voeding het tussen sononder en middernag plaasgevind, met 'n sekondere fase na sonop. Soedoende is temperatuuruiterstes vermy. Temperatuurregulasie en watergebruikpatrone is bestudeer, insluitend temperatuurreguleringsgedrag, haarkleedeienskappe, liggaamskerntemperature, termoneutraliteit en metabolise omset. Voedingsgedrag, voedsel en die voedingswaarde daarvan is ondersoek. Verskille tussen die Oos- en Suid-Kaap in die kwaliteit van voedsel hang saam met die laer vlak van voedingsstowwe in die gronde van die Suid-Kaap. Bosvarkbevolkings in die twee streke toon verskille in populasiedinamika wat hieraan toegeskryf kan word. Groei- en energiestoorpatrone is beskryf. Die moontlikhede is ondersoek om kondisie te evalueer met behulp van parameters soos massa tot grootte-verhoudings, vetneerleggings en bloedwaardes. Aspekte van voortplantingsbiologie, soos geslagsrypheid, vroulike voortplantingssiklusse, voorgeboortelike werpselgroottes, foetale ontwikkeling, laktasie, seisoenaliteit en voortplantingsomset is behandel. Die rol van voedselkwaliteit, kondisie en sosiale status by die bepaling van voortplantingsukses word bespreek. Skattings van die bevolkingsdigtheid van bosvarke in die Suid-Kaap het gewissel tussen 0,3 en 0,5 diere per kmª• Op grond van die verskille in bevolkingsdinamika tussen bosvarke in die Suid- en Oos-Kaap is 'n model ontwikkel om die verband tussen bevolkingsregulering en lewensstrategieeë (life history tactics) te verklaar. Hiervolgens het voedselbeskikbaarheid die tipe sosiale organisasie bepaal terwyl die lewensstrategieë van bevolkings die gevolg is van voedselkwaliteit. Die model stel vaar 'n verband tussen groeipleksomstandighede, voedselkwaliteit, metaboliese omset en bevolkingsdinamika. In die laaste hoofstuk word sommige van die bestuursimplikasies van die navorsingsbevindinge bespreek.