No description available.

In Canada, the endangered prairie skink (Plestiodon septentrionalis) exists only in southwestern Manitoba. Habitat loss is the most significant threat faced by the prairie skink in Canada, with leafy spurge (Euphorbia esula) invasion identified as one of the suspected factors contributing to habitat loss. The objectives of this study were to determine microhabitat preferences and effect of leafy spurge on prairie skinks in southwestern Manitoba. To determine microhabitat preferences, occupied sites were compared to unoccupied sites. Artificial cover was identified as the most important microhabitat element. To determine the impacts of spurge on microhabitat, ground temperatures in invaded were compared to un-invaded sites. No significant differences in temperature or skink density were observed between invaded and un-invaded site; however, skinks were more likely to use spurge when cover was present, than when no cover was present. Artificial cover may improve microhabitat by providing refuge from predators and microhabitat for prey.

In Canada, the endangered prairie skink (Plestiodon septentrionalis) exists only in southwestern Manitoba. Habitat loss is the most significant threat faced by the prairie skink in Canada, with leafy spurge (Euphorbia esula) invasion identified as one of the suspected factors contributing to habitat loss. The objectives of this study were to determine microhabitat preferences and effect of leafy spurge on prairie skinks in southwestern Manitoba. To determine microhabitat preferences, occupied sites were compared to unoccupied sites. Artificial cover was identified as the most important microhabitat element. To determine the impacts of spurge on microhabitat, ground temperatures in invaded were compared to un-invaded sites. No significant differences in temperature or skink density were observed between invaded and un-invaded site; however, skinks were more likely to use spurge when cover was present, than when no cover was present. Artificial cover may improve microhabitat by providing refuge from predators and microhabitat for prey.

abstract: ABSTRACT The elephant tree, Bursera microphylla, is at the northern limit of its range in central Arizona. This species is sensitive to frost damage thus limiting its occurrence in more northern areas of the southwest. Marginal populations of B. microphylla are found in mountain ranges of Central Arizona and are known to occur in the rugged mountain range system of the South Mountain Municipal Park (SMMP). Little is known of the distribution of this species within the park and details relevant to the health of both individual plants and the population such as diameter and number of trunks, height, and presence of damage have not been examined. This study was designed, in part, to test the hypothesis that favorable microhabitats at SMMP are created by particular combinations of abiotic features including aspect, slope, elevation and solar radiation. Data on abiotic factors, as well as specific individual plant locations and characteristics were obtained for 100 individuals. Temperature data was collected in vertical transects at different altitudinal levels. Some of these data were used in spatial analyses to generate a habitat suitability model using GIS software. Furthermore, collected data was analyzed using Matlab© software to identify potential trends in the variation of morphological traits. In addition, for comparative purposes similar information at one hundred computer-generated randomly chosen points throughout SMMP was obtained. The GIS spatial analyses indicated that aspect, slope, elevation, and relative solar radiance are strongly associated as major climatic components of the microhabitat of B. microphylla. Temperature data demonstrated that there are significant differences in ambient temperature among different altitudinal gradients with middle elevations being more favorable. Furthermore, analyses performed using Matlab© to explore trends of elevation as a factor indicated that multiple trunk plants are more commonly found at higher elevations than single trunk plants, there is a positive correlation of trunk diameter with elevation, and that canopy volume has a negative correlation with respect to elevation. It was concluded that microhabitats where B. microphylla occurs at the northern limit of its range require a particular combination of abiotic features that can be easily altered by climatic changes. / Dissertation/Thesis / M.S. Applied Biological Sciences 2011

Submitted by Alberto Vieira (martins_vieira@ibest.com.br) on 2018-01-12T15:51:33Z No. of bitstreams: 1 617462.pdf: 9301397 bytes, checksum: 507a0d494160adf0b5d975c1297dee3e (MD5) / Made available in DSpace on 2018-01-12T15:51:33Z (GMT). No. of bitstreams: 1 617462.pdf: 9301397 bytes, checksum: 507a0d494160adf0b5d975c1297dee3e (MD5) Previous issue date: 2003-10 / FUJB / CAPES / A heterogeneidade espacial e a variação temporal das características bióticas e abióticas do ambiente influenciam a distribuição de diversas espécies animais. Portanto, as interações entre as condições climáticas e a estrutura do ambiente são importantes em qualquer estudo que busque avaliar a dinâmica e os processos ecológicos de uma região. O objetivo desse estudo é avaliar as variações espacial e temporal do microclima, seus efeitos sobre o microhabitat e consequentemente sobre a dinâmica das populações de pequenos mamíferos, numa área de Mata Atlântica. Foi também proposto um método de avaliação da heterogeneidade microclimática nesse tipo de floresta tropical. Para medir as variáveis de microclima (temperatura, umidade e luminosidade), foram usados registradores automáticos, ou seja, aparelhos de leitura programada de parâmetros climáticos. Para caracterizar o microhabitat foram medidas oito variáveis propostas em Freitas et al. (2002). O método desenvolvido e testado é eficiente no estudo do ambiente de pequenos mamíferos que vivem nessa camada de ar junto ao solo. Os resultados mostram diferenças espaciais e temporais das variáveis estudadas, onde a variação espacial do microclima pôde ser atribuída às diferenças de altitude e estruturais locais, e, sua variação temporal afeta a dinâmica do microhabitat. Foram encontrados modelos de preferência de microhabitat para os marsupiais Didelphis aurita (generalista com boa capacidade de manutenção local) e Metachirus nudicaudatus (sub-bosque desenvolvido e menor capacidade de manutenção local), enquanto Marmosops incanus apresentou correlação com o microclima, ocorrendo com populações maiores nos locais mais altos da área de estudo, com temperaturas mais amenas e maior umidade relativa. / The spacial heterogeneity and the temporal variation of the biotics and abiotics characteristics of the environment influence the distribution of animal species. Therefore, the interactions between the climatic conditions and the structure of the environment are important in any study that evaluate the dynamics and the ecological processes of a region. The aim of this study is to evaluate the space and time variations of the microclimate, its effect on the microhabitat and consequentely on the dynamics of the populations of small mammals, in an area of Atlantic Forest. Also a method of evaluation of the microclimate variables (temperature, humidity and luminosity) was developed, where were used data loggers, a programmed reading equipment of climatic parameters. To characterize the microhabitat were measured eight variables proposed in Freitas et al. (2002). The developed and tested method is efficcient in the study of environment of small mammals that live in this layer of air near the ground. The results show spacial and temporal differences of the studied variables, where the spacial variatuon of the microclimate could be attributed to the differences of altitude and in the local structural, and, its temporal variation affects the dynamics of the microhabitat. Models of habitat preference were found for the marsupials Didelphis aurita (generalist with good capacity of local maintenance) and Metachirus nudicaudatus (developed understory and lesser capacity of local maintenance), while Marmosops incanus presented correlation with the microclimate, occurring with bigger populations in the highest places of the study area, with lower temperatures and higher relative humidity.

Neste trabalho foram realizados estudos sobre a dieta e a estratificaÃÃo vertical em D. gr. microcephalus em uma Ãrea de tabuleiro litorÃneo do nordeste brasileiro. Em relaÃÃo à dieta, foram identificados os principais itens alimentares, a ocorrÃncia de variaÃÃo sexual, ontogenÃtica e estacional quanto Ãs presas consumidas, bem como a relaÃÃo do comprimento e volume destas com o comprimento rostro-cloacal e a largura da mandÃbula. Quanto à estratificaÃÃo vertical, foram analisadas possÃveis diferenÃas sexuais, ontogenÃticas e estacionais na altura de empoleiramento. Os trabalhos de campo ocorreram mensalmente de marÃo atà dezembro de 2011, totalizando dez meses de coletas, obtendo-se uma amostra total de 229 indivÃduos (177 machos, 52 fÃmeas). Foram quantificadas 464 presas distribuÃdas em 15 categorias, sendo Diptera, Coleoptera, Araneae e Hemiptera os principais itens consumidos, composiÃÃo alimentar encontrada na maioria das espÃcies do gÃnero. O predomÃnio de dÃpteros na composiÃÃo alimentar aponta Dendropsophus como um grupo importante de biocontroladores de insetos prejudiciais. FÃmeas apresentaram valores maiores do que machos em relaÃÃo ao comprimento rostro â cloacal (CRC), largura da mandÃbula e massa corpÃrea, sendo largura da mandÃbula a responsÃvel pelas diferenÃas sexuais e ontogenÃticas quando relacionada com comprimento e volume dos itens consumidos. Quanto à variaÃÃo estacional, comprimento e volume dos itens alimentares tiveram valores maiores durante a estaÃÃo chuvosa, sugerindo uma abundÃncia maior de presas nesse perÃodo. A altura de empoleiramento em D. gr. microcephalus foi semelhante ao encontrado em outras espÃcies do gÃnero. Adultos se empoleiraram em alturas inferiores, enquanto jovens alcanÃaram alturas maiores, diferenÃas que estÃo relacionadas com a largura da mandÃbula e, possivelmente, com CRC e massa corpÃrea. EstratificaÃÃo vertical devido a variaÃÃes estacionais pode estar ligada a fatores abiÃticos como temperatura, umidade relativa do ar e/ou vento, porÃm, outros estudos devem ser realizados para confirmar a relaÃÃo desses fatores, nÃo sà com as variaÃÃes estacionais, mas tambÃm com as variaÃÃes sexuais e ontogenÃticas. / In this work, it was studied the diet and vertical stratification in D. gr. microcephalus in an area of coastal tableland of northeastern Brazil. Regarding diet, it was identified the main food items, the occurrence of sexual, ontogenetic and seasonal variation in relation to the consumed prey, as well as the ratio of length and volume of these with the snout-vent length and jaw width. As for the vertical stratification, it was analyzed possible sex, ontogenetic and seasonal time differences for perch height. The field work took place monthly from March to December 2011, totalizing ten months of collections, obtaining a sample of 229 individuals (177 males, 52 females). It was quantified 464 prey distributed in 15 categories, being Diptera, Coleoptera, Araneae e Hemiptera the main items consumed,food composition found in most species of the genus. The predominance of Diptera in dietary composition points out Dendropsophus as an important group of biocontrol of harmful insects. Females had higher values than males in relation to snout-vent length (SVL), jaw width (JW) and body mass, being jaw width the responsible for the sexual and ontogenetic differences when related to length and volume of items consumed. With regard to seasonal variation, length and volume of food items were greater during the rainy season, suggesting a greater abundance of prey during this period. The height of perch D. gr. microcephalus was similar to that found in other species of the genus. Adults perched at lower altitudes, while youngsters have reached greater heights, differences that are related to the jaw width and possibly to the SVL and body mass. Vertical stratification due to seasonal variations may be linked to abiotic factors such as temperature, relative humidity and / or wind; however, further studies should be conducted to confirm the relationship of these factors, not only with seasonal variations, but also with sexual and ontogenetic variations.

Redd distribution, redd density, and physical habitat were used to explain the distribution and abundance of young-of-the-year (YOY) brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss) in the Green River, Utah. The importance of variables at both a microhabitat and macrohabitat scale were assessed using stepwise regression analysis. Availability of cover (rock and vegetation) and proximity to spawning sites were the most important variables used to explain the distribution and abundance of YOY brown trout and rainbow trout. In addition, YOY brown trout and rainbow trout occupied specific microhabitats and showed patterns of use for particular depths, substrates, and cover. However, the importance of variables differed by year, indicating that variables other than those measured were also influencing their distribution and abundance. The results of my study indicate that variables at both a microhabitat and macrohabitat scale may be important in explaining the distribution and abundance of YOY trout in streams. Therefore, to better understand the habitat requirements of stream fishes and to better explain their distribution and abundance in streams future, studies may need to incorporate both physical habitat variables and variables affecting recruitment.

No description available.

Field surveys of Strongylocentrotus purpuratus demonstrated that concentrations of natural sunscreens, mycosporine-like amino acids (MAAs), were higher in females than males for both gonadal and epidermal tissues, increased in ovaries as spawning season approached, and were influenced by the sea urchins’ microhabitat. Sea urchins occupying burrows, or “pits”, had lower concentrations of MAAs than those outside pits, suggesting a trade-off between physical and UV protection. Overall, UV irradiance did not influence MAA accumulation in gonadal tissues. However, males increased their allocation of MAAs to epidermal tissues in the microhabitat with the highest irradiance. Relative concentrations of individual MAAs were similar for epidermal tissues from both sexes and ovaries, providing broadband UVA/UVB absorbance, but testes contained principally one MAA, palythine. This is the first study to demonstrate that S. purpuratus and eight species of macroalgae in California have MAAs, and that the concentrations can be influenced by microhabitat.

No description available.