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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Ecology and Behaviour of the Southern River Otter Lontra provocax Thomas 1908 in Chile

Reyes Küppers, Renato 12 October 2007 (has links)
The conducted study on the southern river otter Lontra provocax presents for the first time substantial data and analyses on preferred habitat components, activity pattern, prey availability, diet composition and potential food competitors, as well as a first attempt in age determination. Three southern river otter (1,2) were successfully equipped with radio transmitter. Both females were classified as resident whereas the male southern river otter was classified as temporary resident. Home range (FK 95) was 14358 m and 17675 m respectively. As only one home range was accessible for habitat analysis, the preferred habitat structures were analysed. Thus the plant Chusquea quila is most important for den sites in anthropogenic modified areas. In natural habitat dens were encountered under big trees and overhanging roots. Hunting areas in anthropogenic modified regions show considerably more woody debris than non-hunting areas, as the main prey the crayfish Samastacus spinifrons hides in this substrate. Most of their time southern river otter spent in their dens (60 %). Lontra provocax show cathemeral behaviour and when being active, the time bouts of movement behaviour averaged 2:18 hours.The crustacean species Samastacus spinifrons was the most encountered aquatic prey species in abundance and in total biomass in the river Queule and in the diet of Lontra provocax. Likewise fish may play an important role to meet the southern river otter s daily metabolic requirements. Monthly collected water samples even close to villages, had physico-chemical parameter values well below critical or toxic levels on aquatic species. Age determination was conducted on four male skulls of southern river otter. Tooth wears; tooth abrasions; dental pulp; relative width of dental pulp, incremental cementum lines and sutures of the skull were used for age determination. The animals were classified as juvenile (1), subadult-adult (1) and senior (2).
22

Habitatpreferens hos Anguilla anguilla: makrofyters påverkan på gulålars habitatval under dag och natt / Habitat preference in Anguilla anguilla: the effect of macrophytes on habitat selection during day and at night in yellow eels

Wiklund, Hannah January 2023 (has links)
Aquatic vegetation and different substrates can be important factors for fish habitat. The European eel (Anguilla anguilla) is threatened by habitat loss in freshwater systems during its life stage as a yellow eel. To conserve the species, restoration measures and increased knowledge about its preference for benthic habitats are needed. In this study, I examined how macrophytes with varying densities affected the habitat selection of A. anguilla yellow eels during day and at night. A laboratory experiment was conducted in three stream flumes containing sand and stone habitats, with an open passage where the eels (n = 17) could swim between them. The stone habitat was the same in all flumes, whereas the sand habitat had three macrophytes densities: 14, 7 and 0 m-2. The number of times the eel switched between the habitats, the time to the first habitat switch and the proportion of time spent in each habitat was noted. The result showed no significant effect of vegetation density on the number of habitat switches, the time to the first switch, or the proportion of time the eels spent in each habitat. There was no difference between night and day regarding the number of switches between the habitats. However, the proportion of time spent in the habitats differed between night and day; the eels spent more time in the stone habitat at night than during the day (Z = 2,707, n = 17, p = 0,038). The results suggests that yellow eels are active at night and may leave their resting habitat among the vegetation to search for food when it gets dark. Aquatic vegetation may be an important feature of yellow eel habitat, and to restore these environments, targeted restoration efforts and an increased understanding of macrophyte occurrence and substrate composition are needed. / Akvatisk vegetation och olika bottensubstrat kan vara viktiga faktorer för fiskars habitat. Den Europeiska ålen (Anguilla anguilla) är i sitt livsstadium som gulål hotad av habitatförlust i sötvattensystem. För att bevara arten krävs restaureringsåtgärder och ökad kunskap om artens preferens av bentiska livsmiljöer. I denna studie undersökte jag hur makrofyter av olika täthet påverkade A. anguilla gulålars habitatval på dagen och natten. Ett laboratorieexperiment utfördes i tre strömrännor innehållandes ett sand- och ett stenhabitat, samt en öppen passage där ålarna (n = 17) kunde simma mellan dem. Stenhabitatet var densamma i alla strömrännor medan sandhabitatet hade tre tätheter av makrofyter; 14, 7, samt 0 m-2. Tid till första byte, antal gånger ålarna bytte mellan habitaten och proportionen av tiden som ålarna spenderade i de två habitaten noterades. Resultatet visade ingen signifikant effekt av växttäthet för tiden till första bytet, antalet byten eller proportionen tid som ålarna spenderade i vardera habitat. Det fanns ingen skillnad mellan natt och dag i avseende på antalet byten mellan habitaten. Däremot var proportionen tid som ålarna tillbringade i de två habitaten olika mellan dag och natt; ålarna var mer i stenhabitatet på natten än på dagen (Z = 2,707, n = 17, p = 0,038). Experimentet tyder på att gulålar är nattaktiva och kan lämna sitt vilohabitat bland växterna när det blir mörkt för att söka föda i stenhabitat. Akvatisk vegetation är en viktig del av ålars livsmiljöer och för att återställa dessa behövs riktade restaureringsinsatser och ökad förståelse för makrofyt- och substratpreferens.
23

Seasonal And Diel Patterns Of Manatee Habitat Use

Ross, Monica Ann 01 January 2007 (has links)
State and Federal agencies have created sanctuaries and speed zones to help reduce manatee mortality while incorporating the recreational and commercial resource needs of these same habitats for humans. Specific habitat resources are considered necessary to increase manatee survivorship. We have only recently begun to address how manatees use some of these resources based on physiological or reproductive strategies. In this study, I quantified patterns of habitat use during seasonal and diel periods for different sex and reproductive manatee classes using data from a radio-telemetry study conducted by the Florida Fish and Wildlife Conservation Commission during 1991-1996. I used five environmental geographic data layers: bathymetry, distance to seagrass, distance to shoreline, distance to warm water refuge sites, and distance to fresh water sources, to discriminate seasonal and diel habitat use patterns for different manatee classes: males (M), females with calves (FWC), and females without calves (FNC). Mean occupancy values were calculated for environmental variable locations and seasonal, diel, and manatee class differences were tested using a Multi-Response Permutation Procedure (MRPP). Nonmetric Multidimensional Scaling (NMS) was used to visualize the ordination patterns of the manatee classes and to assess importance of correlated environmental variables. Significant differences in habitat use were noted between summer and winter based on distances to warm water, seagrass, and fresh water sources but similar habitat use patterns were exhibited within summer diel periods among manatee classes. All manatee classes appeared to have used a higher proportion of locations closer in proximity to seagrass at night than day in winter indicating a disproportionate difference in feeding bouts between diel periods. These differences may be attributed to adjusting feeding strategies to reduce thermoregulatory costs or to decrease human interactions. Differences in patterns were exhibited for the winter diel periods specifically for the FWC manatee classes during winter days. FWC had a higher proportion of locations within the warm water refuges during the day indicating a possible trade off situation between food consumption and thermal exposure. This study demonstrates coarse and fine scale patterns of variation in habitat use for manatees both seasonally and daily within winter. It also suggests that during winter months, manatees were not just utilizing their habitat but they appeared to have preferences and selection for certain habitat types. Recovery of a species is greatly enhanced when patterns of habitat use within the species' environment has been clearly defined. Understanding more specifically what types of habitats manatees choose might allow management to adjust strategies for protection of key habitats while encouraging further recovery of this species.
24

Populationsgröße, Trichterdichte und Habitatpräferenz der Dünen-Ameisenjungfer Myrmeleon bore (Tjeder, 1941) im Gebiet der Dresdner Heide (Neuroptera)

Anselmi, A. C. M., Gallon, S. C. E., Müller, P., Reinhardt, K. 04 November 2022 (has links)
Nach dem Erstnachweis von Myrmeleon-Bohrungen (Tjeder, 1941) in der Dresdner Heide im Jahr 2019 (KURTH 2020, Sächs. Entomol. Z. 10: 71-80) wurde die Populationsgröße und Dichte der Art bestimmt. M. bore wurde hauptsächlich in offenen, spärlich bewachsenen, sandigen Gebieten mit direkter Sonneneinstrahlung gefunden. Die flächengewichtete Dichte des gesamten Untersuchungsgebietes (4,05 Hektar) betrug 0,177 Larven/m2. Schätzungen der Populationsgröße basierend auf zufälligen Quadratzahlen führen zu einer Zahl von 4000-7000 Individuen - die größte bekannte Population dieser Art. Die für diese Art aus Laborversuchen bekannte positive Korrelation zwischen Larvengröße und Grubendurchmesser wurde an unserem Studienstandort bestätigt. Diese Korrelation könnte es Forschern ermöglichen, die Altersstruktur von Wildpopulationen abzuschätzen. Angesichts der besonderen Verantwortung Deutschlands für den Schutz dieser Art und der Größe der Population fordern wir den Schutz des Gebietes und eine Priorisierung gegenüber anderen geschützten Arten in diesem Gebiet. / Following the first record of Myrmeleon bore (Tjeder, 1941) in the Dresden Heath area in 2019 (KURTH 2020, Sächs. Entomol. Z. 10: 71-80), the population size and density of the species was determined. M. bore mainly was found in open, sparsely vegetated, sandy areas with direct sunlight exposure. The area-weighted density of the entire study site (4.05 hectares) was 0.177 larvae/m2. Population size estimates based on random quadrat counts lead to a figure of 4000-7000 individuals - the largest known population of this species. The positive correlation between larval size and pit diameter known for this species from laboratory trials was confirmed at our study site. This correlation may allow researchers to estimate the age structure of wild populations. Given the special responsibility of Germany for the protection of this species and the size of the population, we urge the protection of the site and a prioritisation over other protected species found in the area.
25

Dynamique spatiale et temporelle des espèces et de communauté de poissons dans le système d'inondation pulsé de Tonle Sap / Spatial and temporal dynamics of fish species and community in Tonle Sap flood pulse system

Chan, Bunyeth 02 July 2018 (has links)
Le lac Tonle Sap (TSL) est l'un des plus grands lacs du monde et est connu comme un hot-spot de la biodiversité en Asie du Sud-Est. En raison de la grande diversité ainsi que de la productivité élevée de poissons, le lac contribue à un apport important en protéines pour la population cambodgienne. Cette étude vise principalement à étudier (1) la dynamique spatiale et temporelle de la composition des communautés de poissons, (2) les effets des facteurs environnementaux sur la distribution des espèces et (3) l'effet de l'abolition des lots de pêche sur la biomasse, les communautés de poissions et le structure des poissons. En utilisant des méthodes statistiques multivariées sur les données de poissons et de variables environnementales, je suis en mesure de mettre en évidence les principales conclusions suivantes: * Les communautés de poissons du TSL étaient composées de deux assemblages de poissons: l'assemblage du nord, principalement caractérisé par des poissons noirs, et l'assemblage du sud, principalement lié aux poissons blancs, gris et estuariens. Les assemblages de poissons de la période 1994-1995 étaient représentés par l'abondance de tous les groupes fonctionnels, c'est-à-dire les poissons noirs, blancs et gris, et pour la période de 1996 à 1999, les assemblages étaient liés aux poissons blancs et gris. * Les distributions des abondances espèces de poissons n'étaient pas homogènes dans le TSL. De plus, les aires de distributions des espèces étaient différentes et étaient régies par des combinaisons distinctes de caractéristiques de l'habitat et de facteurs climatiques. * H. lobatus et H. siamensis peuvent coexister ensemble, mais la synchronisation et la migration de H. lobatus conduisent toujours à celles de H. siamensis. Ces résultats suggèrent que la population de H. lobatus est plus sensible aux variations d'impulsion de flux que celles de H. siamensis. Ceci indique que les variations des impulsions d'écoulement sont les principaux déterminants responsables de la dynamique temporelle de chaque espèce.[...] / Tonle Sap Lake (TSL) is one of the world's largest lakes and is a biodiversity hotspot in Southeast Asia. It supports high fish productivity which sustains protein supply for millions of people in the region. This study aims to investigate (1) spatial and temporal dynamics of fish community composition, (2) the effects of environmental factors on fish distribution and (3) effects of fishing lot abolishment on fish biomass, community and structure in TSL. By using multivariate statistical methods on fish and environmental data, the thesis highlights that: * There were two fish assemblages in TSL: the northern assemblage, mostly characterised by black fishes, and the southern assemblage, mainly linked to white, grey and estuarine fishes. Fish assemblages from earlier years (1994 and 1995) were represented by the abundances of all functional groups, i.e. black, white and grey fishes, and from 1996 to 1999, the assemblages were linked only to white and grey fishes. * Fish species distributions were not homogeneous within TSL. In addition, species distribution areas were different and were governed by distinct combinations of the local habitat characteristics and regional climatic factors. * H. lobatus and H. siamensis can co-occur together, but synchronisation and migration of H. lobatus always lead those of H. siamensis. These results suggest that the population of H. lobatus is more responsive to flow pulse variations than those of H. siamensis.[...]
26

Estratégias ecológicas de plantas em florestas estacionais e savanas do cerrado / Plant ecological strategies in seasonal forests and savannas of the cerrado

Santos, Leandro Maracahipes dos 13 April 2017 (has links)
Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2017-05-22T15:55:42Z No. of bitstreams: 2 Tese - Leandro Maracahipes dos Santos - 2017.pdf: 3094765 bytes, checksum: a7fa8f585e1539956b511e26bdb50212 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2017-05-22T15:56:58Z (GMT) No. of bitstreams: 2 Tese - Leandro Maracahipes dos Santos - 2017.pdf: 3094765 bytes, checksum: a7fa8f585e1539956b511e26bdb50212 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-05-22T15:56:58Z (GMT). No. of bitstreams: 2 Tese - Leandro Maracahipes dos Santos - 2017.pdf: 3094765 bytes, checksum: a7fa8f585e1539956b511e26bdb50212 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-04-13 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The adoption of different ecological strategies is an important factor to determine the establishment and persistence of species in local communities. In general, the Cerrado is characterized by high fire frequency and poor soils. Generally under conditions of low fertility and high fire frequency the filtered species tend to have characteristics that represent adaptations to these environmental stresses. Considering that savanna species evolved under severe environmental filters, our aim was to evaluate how the adoption of different ecological strategies can determine the performance of the functional traits, the structure of the communities, and the relationship between a focal plant and its neighborhood. In this thesis work, which is divided into three chapters, we use three different scales to evaluate how species ecological strategies can determine the performance and establishment in local communities. In the first chapter, which is based on habitat scale, we evaluated how ecological strategies of generalist and specialist species of seasonal forest and savannas are fundamental for the establishment and persistence of the species in these habitats with marked differences in frequency in fire frequency and nutrient availability. In this chapter, we discuss that the different strategies adopted by species are in accordance to the limiting factors of the species occurrence in each of these environments. In the second chapter, which is based on community scale, we seek to understand how environmental gradients can determine different ecological strategies related to functional traits and density of individuals. We showed that the changes in trait values and density of individuals were more evident in the fertility gradient than toxicity, and that seasonal forest communities were more sensitive to changes savanna communities in both gradients. We also observed that species with conservative traits were associated with poor soils and species with acquisitive traits with more fertile soils. In the third chapter, which was developed at the individual scale, we discussed whether the characteristics and phylogenetic relationship of the neighboring plants influence leaf damage in trees and shrubs of savannas. In this chapter, we showed that the ecological and evolutionary distance between individual plants and neighboring plants does not determine the level of leaf damage by herbivores. We discussed that the dominance of generalist herbivores, co-evolution between plants and specialist herbivores, and preferential consumption of young leaves may be more important to determine the level of leaf damage than the neighboring context in which a given plant is inserted. / A adoção de diferentes estratégias ecológicas é um fator importante para determinar o estabelecimento e a persistência de espécies em comunidades locais. De maneira geral, o cerrado é caracterizado por uma alta frequência de fogo e solos pobres em nutrientes. Geralmente em condições de baixa fertilidade e alta frequência de fogo as espécies filtradas tendem a possuir características que representam adaptações a estes estresses ambientais. Considerando que as espécies de Cerrado se desenvolvem sob a atuação destes filtros ambientais, nosso objetivo foi avaliar como a adoção de diferentes estratégias ecológicas podem determinar a performance dos atributos funcionais, a estrutura das comunidades e a relação entre uma planta focal e sua vizinhança. Neste trabalho de tese, que está dividido em três capítulos, nós utilizamos três diferentes escalas para avaliar como estratégias ecológicas das espécies podem determinar seu desempenho e estabelecimento em comunidades locais. No primeiro capítulo que está baseado em uma escala de habitat, nós avaliamos como as estratégias ecológicas de espécies generalistas e especialistas de floresta estacional e cerrado sentido restrito são fundamentais para o estabelecimento e a persistência das espécies nestes habitats com diferenças marcantes em relação à frequência de fogo e disponibilidade de nutrientes. Neste capítulo, nós discutimos que as diferentes estratégias adotadas pelas espécies estão de acordo com os fatores limitantes da ocorrência de espécies em cada um destes ambientes. No segundo capítulo, que está baseado em escala de comunidades, nós buscamos compreender como os gradientes ambientais podem determinar diferentes estratégias ecológicas relacionadas aos atributos funcionais e a densidade de espécies. Nós demonstramos que as mudanças nos valores de atributos e densidade de espécies foram mais claras no gradiente de fertilidade do que toxicidade, e que comunidades de floresta estacional foram mais sensíveis a mudanças do que comunidades de cerrado sentido restrito em ambos os gradientes. Nós observamos também que espécies com atributos conservativos foram associados à solos pobres e espécies com atributos aquisitivos associado à solos mais férteis. Já no terceiro capítulo, que foi desenvolvido na escala de indivíduo, nós discutimos se as características e relação filogenética das plantas vizinhas influenciam o dano foliar em árvores e arbustos do cerrado. Neste capítulo, demonstramos que a distância ecológica e evolutiva entre plantas individuais e as plantas vizinhas não determina o nível de consumo foliar por herbívoros. Nós discutimos que a dominância de herbívoros generalistas, a co-evolução entre plantas e herbívoros especialistas, e o consumo preferencial de folhas jovens podem ser mais importante para determinar o nível de dano foliar do que o contexto de vizinhança em que uma dada planta está inserida.
27

Natural and human impacts on habitat use of coastal delphinids in the Mossel Bay area, Western Cape, South Africa

James, B.S. (Bridget) 01 1900 (has links)
The south coast of South Africa represents the extreme western end of the range of the Indo-Pacific humpback (Sousa chinensis, plumbea type) and Indo-Pacific bottlenose dolphins (Tursiops aduncus), which are both confirmed to range as far west as False Bay (Jefferson & Karczmarski, 2001; Hammond et al., 2008). Individual ranging behaviour for both species however is not well resolved. Recent genetic analyses suggest that animals currently considered as plumbea type Sousa chinensis (Reeves et al., 2008) may be a separate species, Sousa plumbea (Mendez et al., 2013). In South African waters less than 1000 adult humpback dolphins (Sousa chinensis, plumbea type hereafter “humpback dolphin”) may comprise the entire population (Karczmarski, 1996), while all estimates suggest the bottlenose dolphin (Tursiops aduncus, hereafter “bottlenose dolphins”) population is relatively large, numbering thousands of animals (Cockcroft et al., 1992; Reisinger & Karczmarski, 2010). Both dolphin species are exposed to variable levels of anthropogenic impacts throughout their range including vessel traffic, chemical pollution and habitat degradation associated with coastal development. This thesis describes the results of a study investigating: 1) the environmental and anthropogenic factors which influence the habitat use of humpback and bottlenose dolphins in two adjacent bays on the southern Cape coast, South Africa – Mossel Bay and Vlees Bay; 2) the abundance of humpback dolphins using Mossel Bay and 3) the interaction of these two dolphin species with white sharks, and the influence this has on dolphin group sizes and habitat use in Mossel Bay. Both land-based and boat-based survey platforms were used in this study with land-based data collected during dedicated watch periods at sites in Mossel Bay (n = 6) and Vlees Bay (n = 4) between February 2011 and March 2013, with a focus on humpback and bottlenose dolphins. A surveyor’s theodolite was used at these sites to collect positional data on animals, while behavioural data were collected through direct observation. Boat-based photographic identification surveys were used to collect data on the presence of individual humpback dolphins in Mossel Bay between April 2011 and November 2013. White shark data from Mossel Bay between February 2011 and March 2013 were provided from boat-based chumming surveys for the collection of photo-ID data from the Master’s thesis of Rabi’a Ryklief, based at Oceans Research. Data were analysed using ANOVA’s, Tukey honest significance tests and generalised additive modelling (Wood, 2006) in programme R, while capture histories of humpback dolphins were analysed with RMark (Laake, 2013) using POPAN open population models (Schwarz & Arnason, 1996) and Huggins heterogeneity closed capture models (Huggins, 1989; Chao et al., 1992). Humpback dolphins socialised over sandy beach habitats in both bays, while feeding/foraging occurred over reef systems in Mossel Bay and off fine grained sandy beach habitats in Vlees Bay. Humpback dolphin resting behaviour was observed at a very low frequency and occurred in all of the primary habitat types in Mossel Bay, while in Vlees Bay resting was only observed over reefs. Bottlenose dolphins in both bays preferentially used wave cut rocky platform habitats for feeding/foraging and resting while socialising occurred in the vicinity of estuaries in Mossel Bay and fine grained sandy beach habitats in Vlees Bay. Higher sighting rates were recorded in the control site, Vlees Bay, than in Mossel Bay for both dolphin species. The largest reverse osmosis desalination plant commenced operations in the sheltered corner of Mossel Bay in October 2011 and discharged approximately five million litres (Ml) of effluent per day (between October 2011 and February 2012) and 18 Ml per day in March and April 2012. In Mossel Bay higher sighting rates of humpback dolphins occurred in the period before desalination began while bottlenose dolphin sighting rates were highest after active desalination decreased to once per month (May, 2012). During the period of peak brine discharge in Mossel Bay, sighting rates were highest for both species in Vlees Bay. Even after desalination operations decreased the sighting rate of humpback dolphins remained low. The operation of the desalination plant at full capacity in Mossel Bay may have led to reduced use of this area by both humpback and bottlenose dolphins. Key habitats in Mossel Bay for both dolphin species are shared with great white sharks (Carcharodon carcharias hereafter “white sharks”) and focus around the three estuaries and their associated near-shore reef systems. The presence of predatory white sharks may limit the time dolphins spend in a specific habitat and influence the number of animals within groups, with larger humpback dolphin groups at sites with high shark utilisation. Both dolphin species had lower individual sighting rates during periods when white shark abundance peaked. Large group sizes of humpback dolphins at Seal Island, and of bottlenose dolphins at Hartenbos and Tergniet, combined with increased rates of travelling and decreased resting and socializing suggest that these areas may pose the largest threat to dolphins due to the variety of shark size classes’ present, especially larger sharks. Closed capture models generated within year population estimates ranging from 48 to 97 individual humpback dolphins (2011: 97, 95% CI: 46 – 205; 2012: 48, 28 – 81; 2013: 68, 35 – 131) while open population modelling produced a ‘super-population’ estimate of 116 animals (95% CI: 54 – 247) using Mossel Bay. During the study 67 humpback dolphins were individually identified with 94.3 % of the individuals in good quality photographs distinctively marked. Fewer humpback dolphins may be present on the south-east and southern Cape coast, including between Algoa Bay and Mossel Bay, than initially thought (Karczmarski, 1996), as definite links exist between Algoa Bay and Plettenberg Bay (Smith-Goodwin, 1997), and Plettenberg Bay and Mossel Bay (this study). The Gouritz River mouth (21º 53' E; Ross, 1984) and De Hoop (20º 30' E; Findlay et al., 1992) were previous suggested as the western limit of this species, but within the last 20 years knowledge on the extent of their range has been greatly improved, and range extension of this species may be occurring to the west with animals present as far west as False Bay (18º 48' E; Jefferson & Karczmarski, 2001). Due to the vulnerability of this species and their wide ranging behaviour, conservation plans need to be implemented on a wide scale to ensure protection of these animals from human impacts throughout their range. A concerted effort is required to further establish the population links between the various locations on the southern Cape coast that these animals frequent. / Dissertation (MSc)--University of Pretoria, 2014. / Zoology and Entomology / MSc / Unrestricted
28

The morphology, reproductive biology and habitat utilisation of the exotic invasive lizard, the brown anole (anolis sagrei), in Taiwan

Norval, Gerrut 12 1900 (has links)
Surveys and vegetation analyses were used to determine the known distribution and the characteristics of the habitat utilised by Anolis sagrei in Taiwan. Sampled lizards were used for morphological comparisons, and to investigate the reproductive biology of this species in Taiwan. The results of this study indicate that the distribution of A. sagrei in Taiwan is extensive (≥237 ha) in Chiayi City and County (southwestern study site) and scattered (≥8 ha) in Hualien City and County (eastern study site). These lizards were mostly found in open sunny degraded man-made habitats. Although some variations were noted in the comparisons between the A. sagrei collected from the two study sites, it was concluded that the two populations likely have the same founder population. The reproductive biology study indicated that photoperiod and the associated temperatures determine the reproductive cycles in A. sagrei. It also demonstrated that reproduction in this species is energetically demanding. / Nature Conservation / MSc.(Nature Conservation)
29

The morphology, reproductive biology and habitat utilisation of the exotic invasive lizard, the brown anole (anolis sagrei), in Taiwan

Norval, Gerrut 12 1900 (has links)
Surveys and vegetation analyses were used to determine the known distribution and the characteristics of the habitat utilised by Anolis sagrei in Taiwan. Sampled lizards were used for morphological comparisons, and to investigate the reproductive biology of this species in Taiwan. The results of this study indicate that the distribution of A. sagrei in Taiwan is extensive (≥237 ha) in Chiayi City and County (southwestern study site) and scattered (≥8 ha) in Hualien City and County (eastern study site). These lizards were mostly found in open sunny degraded man-made habitats. Although some variations were noted in the comparisons between the A. sagrei collected from the two study sites, it was concluded that the two populations likely have the same founder population. The reproductive biology study indicated that photoperiod and the associated temperatures determine the reproductive cycles in A. sagrei. It also demonstrated that reproduction in this species is energetically demanding. / Nature Conservation / MSc.(Nature Conservation)
30

Intraspecific Variation in Natal Plant Secondary Chemistry Leads to Plasticity in Lepidopteran Oviposition Behavior

Ryan, Sean F. 19 July 2011 (has links)
No description available.

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