Made available in DSpace on 2015-03-05T16:20:41Z (GMT). No. of bitstreams: 0 Previous issue date: 31 / Bolsa para curso e programa de Pós Graduação / A construção de estradas é um fator de perturbação de alto impacto, removendo a cobertura vegetal original, gerando efeito de borda e alterando a função e a estrutura da paisagem. Este tipo de modificação acarreta em sérios impactos à fauna de vertebrados em processo de deslocamento, que se vêem forçados a superar essas barreiras artificiais, elevando o índice de mortalidade. Nesse contexto, investigamos a fauna de mamíferos atropelados em uma região inserida no Bioma Pampa no oeste do Rio Grande do Sul.

African savannas have experienced considerable woody encroachment over the last century, presenting an increasing problem from both ecological and socioeconomic viewpoints. Despite decades of work by savanna ecologists, the reasons for woody encroachment remain unclear. A major barrier to understanding the causes is the difficulty of disentangling the effects of broader-scale environmental changes, such as climate change and associated increases in atmospheric CO2, from localised effects such as fire. In this thesis I examine the effects of sixty years of experimental burning on the characteristics of woody vegetation in two climatically distinct African savannas, a wet and a dry savanna, to examine how long-term burning interacts with other potential drivers of woody encroachment. I examine tree abundance, woody cover, tree structure, diversity and community composition under four different fire regimes: annual, biennial, triennial and fire exclusion. Differences between sites and plots subject to different burning regimes are compared along with changes in these differences through time. Additionally, variation in the densities of Acacia, Combretum, Terminalia and Dichrostachys species were examined to establish how dominant species, particularly those responsible for encroachment, are affected by fire. Overall, I found that the effects of fire depend on savanna type. Fire lowered tree abundance and woody cover much more in the wet savanna than in the dry savanna. However, the maximal height of trees was much more constrained by increased fire frequency in the dry savanna than in the wet savanna. Woody encroachment occurred across both savanna types during the sixty year time period, but was much more rapid at the wet savanna. Additionally, encroaching species of Dichrostachys cinerea and Terminalia sericea in the wet savanna were shown to be more difficult to manage using fire. Overall as fire regimes were kept constant over the last sixty years, yet woody encroachment occurred across all fire treatments, it is most likely that an external driver is responsible. Rainfall change in both areas was minimal over the duration of the study, thus increased atmospheric CO2 would appear to be the most likely cause of woody encroachment. However, the magnitude and characteristics of woody encroachment are strongly mediated by fire and rainfall. Wet savannas would appear to be much more vulnerable to woody encroachment and existing management strategies are likely to become increasingly ineffective at keeping woody cover below potential maximum levels. Overall this thesis demonstrates that the effects of fire on woody vegetation in savannas vary depending on regional differences in rainfall and that processes of woody encroachment differ depending on savanna type.

Este trabalho foi realizado numa paisagem composta por 7 diferentes fisionomias de cerrado e uma floresta homogênea de eucaliptos, adjacente ao cerrado. Durante 12 meses amostrou-se os mamíferos mensalmente, por 3 noites consecutivas, procurando cobrir as variações sazonais de períodos secos e chuvosos, utilizando-se 2 tipos de armadilhas para os pequenos mamíferos: gaiola, dispostas ao longo das trilhas, de 25 em 25m, totalizando 114 armadilhas, amostrando todas diferentes fisionomias; e uma estação de pitfall, com 4 baldes de 40cm cada um, em cada fisionomia. O esforço de coleta foi de 4.896 trapnigths e 324 estações/ dia de pitfall, onde capturou-se 121 indivíduos de 12 gêneros, sendo 8 de roedores (Oligoryzomys sp, Calomys sp, Akodon sp, Oryzomys sp, Bolomys lasiurus, Pseudoryzomys simplex, Oxymicterus sp, Nectomys squamipes) e 4 de marsupiais (Didelphis albiventris, Marmosa sp, Gracilinanus microtarsus, Micoureus cinereus). A espécie dominante da comunidade é do gênero Oligoryzomys sp. O N. squamipes aparece sempre intimamente relacionado à água, já os gêneros B. lasiurus, Pseudoryzomys sp, Oxymicterus sp ocorrem em regiões de campo aberto. Os marsupiais G. microtarsus e Marmosa sp preferem fisionomias arbustivas de cerrado, já o M. cinereus, P. opossum, e D. albiventris preferem formações mais florestais, sendo este último, ao lado do Oligoryzomys sp os únicos a utilizar o reflorestamento. O maior número de capturas ocorreu no período seco e o nímero de roedores capturados foi muito maior que o de marsupiais. O maior valor de H’ apareceu na fisionomia de mata de transição entre cerradão e floresta ripária. Apesar do pitfall parecer um método muito mais eficiente que as armadilhas de gaiola, este estudo mostrou que os dois métodos são complementares, pois aquelas espécies que são capturadas nos pitfalls, com raras exceções, são capturadas também pelas gaiolas. As espécies de menor tamanho corporal foram capturadas nos pitfalls, como Oligoryzomys sp, Calomys sp, Gracilinanus microtarsus, Marmosa sp, já aquelas de maior tamanho corporal foram capturadas nas gaiolas, como Nectomys squamipes, Pseudoryzomys simplex, Oryzomys sp, Oxymicterus sp, Micoureus cinereus, Didelphis albiventris. Somente duas espécies foram capturadas tanto nas armadilhas quanto nos pitfalls, o Akodon sp e o Bolomys lasiurus. O cálculo do índice da Jaccard (= 0,17) forneceu um resultado que corrobora a idéia de que os dois tipos de armadilhas são complementares num estudo da comunidade de pequenos mamíferos. / The work has been performed in a landscape coposed of seven different Brazilian savanna physiognomie and an eucalyptus forest, adjacent of the Brazilian savanna. Small mammals, during 12 moths, were sampled, every 30 days for 3 consecutive nights, in dry and wet seasons, through 2 kinds of small mammal traps: Tomahawk style, arranged along trails, every twenty 5 meters, amounting a 114 traps sampling all physiognomies; and a pitfall satation, with four 40 centimeter deep buckets each, in each physiognomy. The capture effort was 4 896 tapnights and 324 pitfall/stations/day where a 121 individuals were captured, in 12 genera, with 8 rodents (Oligoryzomys sp, Calomys sp, Akodon sp, Oryzomys sp, Bolomys lasiurus, Pseudorizomys simplex, Oxymicterus sp, Nectomys squamipes) and 4 marsupials (Didelphis albiventris, Marmosa sp, Gracilinanus microtarsus, Micouerus cinereus). The community dominant specie is Oligoryzomys sp. The N.squamipes always appears closely related to water. In contrast, B. lasiurus, P. simplex and Oximycterus sp occur in open field regions. The marsupials G. microtarsus and Marmosa sp prefer Brazilian savannas shrubby vegetation, whereas M. cinereus, P. opossum and D. albiventris commonly use forested vegetation, and the llatter, side with the Oligoryzomys sp are the only ones to exploit the reforest areas. The largest number of captures occurred in the transition forest between the cerradão and the riparian forest. Despite of the fact that, pitfalls may seem a much more efficient method than Tomahawk traps themselves, said work has proved both methods to be complementary for those species were captured through pitfalls, with rare exceptions, were captured through Tomahawk traps as well. The smaller body mass species were captured through pitfalls, like Oligoryzomys sp, Calomys sp, G. microtarsus, Marmosa sp, whereas the bigger body mass ones were captured through Tomahawk traps, such as N. squamipes, P. simplex, Oryzomys sp, Oxymicterus sp, M. cinereus, D. albiventris. Only two species were captured through both methods Akodon sp and B. lasiurus. The Jaccard index (=0,17) performed a result that corroborates the idea that the two kinds of traps are complementary in a small mammals community study.

A soja é hoje a principal oleaginosa do Brasil, cultivada em todas as latitudes do país é o mais importante produto agrícola de exportação. O alto custo das adubações e a importância da nutrição mineral sobre a produtividade, tornam imprescindível a utilização de técnicas de avaliação do estado nutricional como a diagnose foliar. O Sistema Integrado de Diagnose e Recomendação (DRIS) utiliza o conceito de balanço de nutrientes e parece estar menos sujeito as interferências de particularidades locais do ambiente e dos sistemas de amostragem das plantas. O presente trabalho teve por objetivo testar diferentes métodos de cálculo das funções DRIS, estabelecer uma norma de referência DRIS e avaliar o estado nutricional da cultura da soja nas regiões compreendidas pelo sul do Maranhão sudoeste do Piauí e Mato Grosso. Foram utilizados 1555 resultados de análise química foliar e produtividade dos campos de produção das regiões do sul do Maranhão e sudoeste do Piauí e 5734 resultados de análise química foliar e produtividade dos campos de pesquisa e produção do Mato Grosso. A amostragem consistiu na coleta da folha diagnóstico, que corresponde à terceira ou quarta folha com pecíolo a partir do ápice de 50 plantas por talhão em pleno florescimento. A sub-população de alta produtividade, nutricionalmente equilibrada, foi determinada pela melhor correlação do Índice de Balanço Nutricional (IBN) com a produtividade do banco de amostras. Foram testadas as metodologias DRIS de Beaufils (1973), Jones (1981) e Elwali & Gascho (1984) para obtenção dos índices DRIS, nos quais as relações foram escolhidas pelo método da razão das variâncias. Os índices DRIS foram classificados em deficiente, normal e excessivo e comparados com o critério das faixas de suficiência. As metodologias de cálculo das funções DRIS (Beaufils, 1973; Jones, 1981; Elwali & Gascho, 1984) apresentaram resultados semelhantes no diagnóstico nutricional da soja nas regiões estudadas. A relação entre a produtividade e o IBN foi melhor quando as normas DRIS foram estabelecidas utilizando a população de referência com produtividade ≥3600 kg ha-1 para as regiões do sul do Maranhão e sudoeste do Piauí e ≥4800 kg ha-1 para Mato Grosso. O método de cálculo das funções DRIS proposto por Jones (1981) foi escolhido para avaliação do estado nutricional da soja nas regiões do sul do Maranhão e sudoeste do Piauí e Mato Grosso pela sua facilidade de utilização. O cobre foi o nutriente mais limitante para a produtividade da soja nas regiões do sul do Maranhão e sudoeste do Piauí. Fósforo foi o nutriente mais limitante para a produtividade no Mato Grosso. O método DRIS, utilizando normas especificas para as regiões do sul do Maranhão e sudoeste do Piauí e para o Mato Grosso, foi eficiente no diagnóstico nutricional da soja. / Nowadays, soybean is the main oleaginous plant in Brazil, cultivated in all latitudes of the country it is the most important agricultural product of exportation. The high cost of fertilization and the importance of the mineral nutrition over productivity, make indispensable the use of evaluation techniques for the nutritional status as well as the foliar diagnosis. The Diagnosis and Recommendation Integrated System (DRIS) uses the concept of nutrient balance, it seems to be less subject to the interference of local particularities of the environment and of the systems of plant sampling. The aim of the present work was to test different methods of DRIS calculation functions, to establish a DRIS reference norm, and to evaluate the nutritional status of soybean in the areas comprehended by the south of Maranhão and southwest of Piauí and Mato Grosso. The study used 1555 results of foliar chemical analysis and productivity of production fields in the southern areas of Maranhão and the southwestern areas of Piauí and 5734 results of foliar chemical analysis and productivity of the research fields and production of Mato Grosso. The sampling consisted in collecting the diagnostic leaf corresponding to the third or fourth leaf with petiole, starting from the apex of 50 plants per planting field in full blooming. The sub-population of high productivity, nutritionally balanced, was determined by the best correlation of Index of Nutritional Balance (INB) with the productivity of the sampling bank. The methodologies DRIS Beaufils (1973), Jones (1981), and Elwali & Gascho (1984) were tested in order to obtain the DRIS indices, for which relationships were chosen using the method of variance ratio. The DRIS indices were classified as deficient, normal, and excessive. They were compared with the criterion of the sufficiency ranges. The methodologies of calculation DRIS functions (Beaufils, 1973; Jones, 1981; Elwali & Gascho, 1984) presented similar results in nutritional diagnosis of soybean in the studied areas. The relation between the productivity and INB was better when DRIS norms were established using the reference population with productivity ≥3600 kg ha-1 for the southern areas of Maranhão and southwestern areas of Piauí and ≥4800 kg ha-1 for Mato Grosso. The method of calculation DRIS functions proposed by Jones (1981) was chosen to evaluate the nutritional status of soybean in the southern areas of Maranhão and southwestern areas of Piauí and Mato Grosso for its usefulness easiness. Copper was the most limiting nutrient for soybean productivity in the southern areas of Maranhão and southwestern areas of Piauí. Phosphorus was the most limiting nutrient for the productivity in Mato Grosso. The DRIS method using specific norms in the southern areas of Maranhão and southwestern areas of Piauí and to Mato Grosso, was efficient in the nutritional diagnosis of soybean.

The aim of this thesis is to evaluate the capability of radio detection and ranging (radar) data collected by the Advanced Land Observing Satellite (ALOS) Phased Array type L-band Synthetic Aperture radar (PALSAR), supported by field measurements obtained through ground survey, to predict and map Above Ground Woody Biomass (AGWB) in the tropical savannas of the developing country of Belize, and to understand how the forest structure may influence the backscatter observed. Firstly, an extensive inventory of the woody vegetation of the tropical savannas of Belize was created by measuring the diameter at breast height (dbh), the total height (ht) and the location of 6547 trees in plots covering a total woodland area of 30.8 hectares, located within four protected areas (the Rio Bravo Conservation and Management Area (11×1ha), Deep River (108×0.1ha) and Manatee Forest Reserve (1ha) and the Bladen Nature Reserve (1ha) and also from plots located in unprotected areas (7×1ha). These measurements of forest structure, when combined with information about forest management practices obtained from local organisations revealed that different forms of protection and management may lead to the development of pine woodlands with different structural characteristics in these savannas. Secondly, a case-study was conducted to establish the sensitivity of the ALOS PALSAR backscatter data to AGWB and determine the effect of sample plot size to their relationship. The findings of this case-study show that the L-band backscatter in these low density pine woodlands is a possible predictor of AGWB and confirm that the appropriate sample plot size for predicting AGWB is one hectare; while the sensitivity degrades significantly with decreasing sample plot size. Taken together, the findings described above were combined to assess the capability of ALOS PALSAR backscatter to predict AGWB in these woodlands. A semi-empirical Water Cloud Model (WCM) describing the interaction between the backscatter and vegetation was re-arranged to enable the prediction of AGWB. Non-linear regression analysis revealed that the ALOS PALSAR backscatter predicted AGWB with an R2=0.92; an external validation conducted with additional ground reference data estimated this AGWB prediction to have an RMSE ~13 t/ha. The form of the regression model linking backscatter to AGWB appears to be particularly influenced by sample plots with higher tree numbers and by plots in which the trees were more homogeneous. The presence of many similar sized individuals within some plots is postulated as one explanation for the elevated saturation level for predictions in this study (> 100 t/ha) compared to other models. The model developed here predicts complete saturation in the backscatter - AGWB relationship to occur primarily as a result of increases in the tree number density and often concurrently in basal area, two parameters which are usually strongly correlated with AGWB in these woodlands. Thirdly, the locally validated relationship between ALOS PALSAR backscatter and AGWB is used to map AGWB for the lowland pine savannas of Belize at a spatial resolution of 100m. The mapping estimates that over 90% of these pine woodlands have an AGWB below 60 t/ha, with the average woody biomass estimated at 23.5 t/ha. When these new predictions are mapped and aggregated over the extents of two protected areas (Rio Bravo and Deep River), the totals obtained agree closely (error ≤20%) with previous estimates of AGWB obtained from ground data and previous research. The combined evidence suggests that woodland protection may produce a small, positive effect upon AGWB, with the mean of the AGWB/ha predictions higher in areas that are protected and managed for biodiversity (29.55 ± 0.84 t/ha) than in other areas that are not protected (23.29 ± 0.19 t/ha). When the fine scale local AGWB mapping produced using ALOS PALSAR is compared cell-by-cell with global biomass products at coarser spatial resolutions (500m and 1000m), the AGWB differences observed range from 115-120%. When the coarser AGWB estimates are aggregated over the extents of Deep River and Rio Bravo, the AGWB totals obtained differ significantly (~280 – 300%) from AGWB estimates from ground data and previous research. Overall, these findings suggest that where sufficient ground data exists to build a reliable local relationship to radar backscatter, more detailed biomass mapping can be produced from ALOS and similar satellite sensor data at resolutions of ~100m. This more accurate and spatially detailed information about the distribution of woody biomass within tropical lowland savannas is more appropriate for monitoring local changes in forest cover and for supporting management decisions for forested areas of around ~10,000ha than estimates based upon previously available, but coarser scale, global biomass products.

Este trabalho foi realizado numa paisagem composta por 7 diferentes fisionomias de cerrado e uma floresta homogênea de eucaliptos, adjacente ao cerrado. Durante 12 meses amostrou-se os mamíferos mensalmente, por 3 noites consecutivas, procurando cobrir as variações sazonais de períodos secos e chuvosos, utilizando-se 2 tipos de armadilhas para os pequenos mamíferos: gaiola, dispostas ao longo das trilhas, de 25 em 25m, totalizando 114 armadilhas, amostrando todas diferentes fisionomias; e uma estação de pitfall, com 4 baldes de 40cm cada um, em cada fisionomia. O esforço de coleta foi de 4.896 trapnigths e 324 estações/ dia de pitfall, onde capturou-se 121 indivíduos de 12 gêneros, sendo 8 de roedores (Oligoryzomys sp, Calomys sp, Akodon sp, Oryzomys sp, Bolomys lasiurus, Pseudoryzomys simplex, Oxymicterus sp, Nectomys squamipes) e 4 de marsupiais (Didelphis albiventris, Marmosa sp, Gracilinanus microtarsus, Micoureus cinereus). A espécie dominante da comunidade é do gênero Oligoryzomys sp. O N. squamipes aparece sempre intimamente relacionado à água, já os gêneros B. lasiurus, Pseudoryzomys sp, Oxymicterus sp ocorrem em regiões de campo aberto. Os marsupiais G. microtarsus e Marmosa sp preferem fisionomias arbustivas de cerrado, já o M. cinereus, P. opossum, e D. albiventris preferem formações mais florestais, sendo este último, ao lado do Oligoryzomys sp os únicos a utilizar o reflorestamento. O maior número de capturas ocorreu no período seco e o nímero de roedores capturados foi muito maior que o de marsupiais. O maior valor de H’ apareceu na fisionomia de mata de transição entre cerradão e floresta ripária. Apesar do pitfall parecer um método muito mais eficiente que as armadilhas de gaiola, este estudo mostrou que os dois métodos são complementares, pois aquelas espécies que são capturadas nos pitfalls, com raras exceções, são capturadas também pelas gaiolas. As espécies de menor tamanho corporal foram capturadas nos pitfalls, como Oligoryzomys sp, Calomys sp, Gracilinanus microtarsus, Marmosa sp, já aquelas de maior tamanho corporal foram capturadas nas gaiolas, como Nectomys squamipes, Pseudoryzomys simplex, Oryzomys sp, Oxymicterus sp, Micoureus cinereus, Didelphis albiventris. Somente duas espécies foram capturadas tanto nas armadilhas quanto nos pitfalls, o Akodon sp e o Bolomys lasiurus. O cálculo do índice da Jaccard (= 0,17) forneceu um resultado que corrobora a idéia de que os dois tipos de armadilhas são complementares num estudo da comunidade de pequenos mamíferos. / The work has been performed in a landscape coposed of seven different Brazilian savanna physiognomie and an eucalyptus forest, adjacent of the Brazilian savanna. Small mammals, during 12 moths, were sampled, every 30 days for 3 consecutive nights, in dry and wet seasons, through 2 kinds of small mammal traps: Tomahawk style, arranged along trails, every twenty 5 meters, amounting a 114 traps sampling all physiognomies; and a pitfall satation, with four 40 centimeter deep buckets each, in each physiognomy. The capture effort was 4 896 tapnights and 324 pitfall/stations/day where a 121 individuals were captured, in 12 genera, with 8 rodents (Oligoryzomys sp, Calomys sp, Akodon sp, Oryzomys sp, Bolomys lasiurus, Pseudorizomys simplex, Oxymicterus sp, Nectomys squamipes) and 4 marsupials (Didelphis albiventris, Marmosa sp, Gracilinanus microtarsus, Micouerus cinereus). The community dominant specie is Oligoryzomys sp. The N.squamipes always appears closely related to water. In contrast, B. lasiurus, P. simplex and Oximycterus sp occur in open field regions. The marsupials G. microtarsus and Marmosa sp prefer Brazilian savannas shrubby vegetation, whereas M. cinereus, P. opossum and D. albiventris commonly use forested vegetation, and the llatter, side with the Oligoryzomys sp are the only ones to exploit the reforest areas. The largest number of captures occurred in the transition forest between the cerradão and the riparian forest. Despite of the fact that, pitfalls may seem a much more efficient method than Tomahawk traps themselves, said work has proved both methods to be complementary for those species were captured through pitfalls, with rare exceptions, were captured through Tomahawk traps as well. The smaller body mass species were captured through pitfalls, like Oligoryzomys sp, Calomys sp, G. microtarsus, Marmosa sp, whereas the bigger body mass ones were captured through Tomahawk traps, such as N. squamipes, P. simplex, Oryzomys sp, Oxymicterus sp, M. cinereus, D. albiventris. Only two species were captured through both methods Akodon sp and B. lasiurus. The Jaccard index (=0,17) performed a result that corroborates the idea that the two kinds of traps are complementary in a small mammals community study.

A study of habitat selection by large wild ungulates was carried out on a 50 cm2 area in the sub-tropical Lowveld region of eastern Transvaal province, South Africa. Estimations were made of herbaceous forage net productivity and ungulate secondary productivity on the same area. Fourteen vegetation types, varying in composition and structure from open savanna to dense woodland, were delineated by association analysis. Structural and vegetational characteristics which were considered to influence ungulate distribution were measured within each vegetation type. The study area supported resident populations of seven ungulate species during the wet season; drv season densities were higher due to population influxes from surrounding areas. Densities ranged from 13 to 67 animals per km2, with impala making up from 40 to 70 percent of the total population, wildebeest 10 to 40 percent, and lesser proportions of giraffe, zebra, kudu, warthog and waterbuck. Savanna vegetation types supported total densities of up to 185 animals/km2, while wooded types support fewer animals. Waterbuck were the most selective of the ungulates and concentrated mainly in the riparian woodland. Wildebeest, zebra and giraffe made variable use of savanna and open woodland types. Warthog preferred savanna types and avoided woodland. Impala were less selective, and kudu showed no habitat preferences. Ungulate distribution was related to several habitat characteristics, and the key factors were found to differ in each case. Each species had a unique combination of habitat characteristics to which it responded in linear fashion, and this was considered to be the way in which ungulates avoided competition by achieving spatial separation. Herbaceous forage standing crops and net production were functions of vegetation composition, soil types, rainfall and extent of ungulate utilization. Standing crops ranged from 350 to 4104 kgs/ha air-dried forage. Net primary production ranged from zero to 2719 kgs/ha; vegetation types on sandy soils did not produce in years with poor precipitation. Ungulates consumed about one-fourth of the herbaceous net primary production during the wet season and more than four-fifths during the course of a full year. Ungulate biomass on the area averaged about 40 kg/ha during the wet season and 65 kg/ha in the dry season, but biomasses varied a great deal with vegetation type, ungulate population species coMposition and seasonal densities. Ungulate secondary product ion varied correspondingly and ranged from 1.3 x 10-3 kcal/m2 per day to 4.8 x 10-3 kcals/m2 per day. Overall secondary production rate for the 2-year study period was 0.97 kcals/m2 per year, produced from a mean standing crop of 7.46 kcal/m2.

There is currently a decline in large, old trees within many ecosystems where they play important ecological and economic roles. One ecosystem suffering from this decline is the bushveld savanna of South Africa. One particularly important species in decline is the ecologically, economically, and culturally significant marula tree (Sclerocarya birrea subsp. caffra). This species’ decline is characterized by a steep drop in recruitment of seedlings into the population. Rodents are known to influence plant communities across many ecosystems through herbivory of adult plants as well as predation of seeds and seedlings. This research provides a record of rodent species present in the bushveld savanna ecosystem of Balule Nature Reserve where a decline in marula recruitment is taking place. Further, it offers a summary of morphological statistics and natural history traits for these rodents. Morphological statistics can be used for species identification. Reproductive status of individuals can inform researchers about reproductive phenology and how it may be affected by environmental conditions. Finally, trapping for this study took place during an historic regional drought. Trapping success was used to develop a limited window into how reduced precipitation affects rodent abundances. Morphological traits measured coincide with those available in the literature. Reproductive activity for males and females of one species, Namaqua rock mouse (Micaelamys namaquensis ), did not overlap completely, with females not being reproductively active while males were. Individuals captured and identified as chestnut climbing mice (Dendromus mystacalis) had statistically significantly longer tails and hind feet, and were heavier than reported in reference works.

<p>Southern Africa harbours one-third of the world&rsquo / s Testudinid species, many of which inhabit arid or semi-arid areas, but ecological information on these species is scant. I studied the habitat, morphology and ecology of Kalahari tent tortoises over 13 months in semi-arid Savanna at Benfontein farm, Northern Cape Province, South Africa. In order to allow continuous monitoring of individuals, I attached radiotransmitters to males and females, split equally between two habitats, sites E (east) and W (west), with apparent differences in vegetation structure. Results of the study were based on data obtained from 27 telemetered tortoises and 161 individuals encountered opportunistically. Female Kalahari tent tortoises were larger than males and the sex ratio did not differ from 1:1. Based on person-hours to capture tortoises, the population appeared to have a low density, with more time required to capture a juvenile (35 hours) than an adult (10-11 hours). The frequency distribution of body size ranges was indicative of recruitment. Relative age, based on annuli counts, suggested that males were younger than females, perhaps because males as the smaller sex are more predation-prone than females. Linear relationships between annuli counts and shell volume indicated that, after reaching sexual maturity, female body size increased faster in volume than did male body size, possibly because a larger volume may enhance female reproductive success. Body condition differed between sites, sexes and among seasons. The hot and dry summer may account for low summer body condition, whereas vegetation differences and size effects, respectively, may account for the low body condition of tortoises in site W and in males. Site E was sandy with grasses, particularly Schmidtia pappophoroides, being the prevalent growth form. This habitat resembled a Savanna vegetation type Schmidtia pappophoroides &ndash / Acacia erioloba described for a neighbouring reserve. Site W was stonier, dominated by shrubs, and was reminiscent of Northern Upper Karoo vegetation (NKu3). Neither site resembled Kimberley Thornveld (SVk4), the designated vegetation type of the area. Differences in substrate and grazing intensity may have contributed to site vegetation differences. Rainfall had an important influence on seasonal vegetation. Short grass abundance correlated with rainfall and annual plants sprouted after spring rain. Refuge use changed according to season and sex. Males selected denser refuges than females did, perhaps because males were smaller and more vulnerable to predation and solar heat. Tortoises selected sparse, short grass as refuges in cool months, probably to maximise basking whilst remaining in protective cover. During hot periods, mammal burrows were preferred to vegetation as refugia. The smaller males spent more time in cover than females, which may be related to predator avoidance or thermoregulation.&nbsp / Females spent more time basking than males, perhaps due to their larger size and to facilitate reproductive processes. Tortoises did not brumate, but through a combination of basking, and orientation relative to the sun in their refuges, managed to attain body temperatures that allowed small bouts of activity. Body temperature for active tortoises was similar among seasons, and was higher for more specialised active behaviours, such as feeding and socialising, than for walking. Increased activity by males in spring could relate to mating behaviour while females were more active in autumn, when they foraged more than males, perhaps due to the high cost of seasonal reproductive requirements. Males displaced further per day than did females, but home range estimates did not differ between sexes. Annual home range estimates varied substantially among individuals: 0.7&ndash / 306 ha for minimum convex polygons and 0.7&ndash / 181 ha for 95% fixed kernel estimates. The ability to&nbsp / cover large areas would assist tortoises in finding resources, e.g., food, in an area where resource distribution may be patchy. Differences among seasonal home ranges and movements probably reflect seasonal climatic change / activity areas shrinking when temperatures were extreme. In order to assess the effects of a semi-arid environment on the morphology of P. oculifer, I compared its morphology to that of its &lsquo / cool-adapted&rsquo / sister taxon Psammobates geometricus, using live and museum specimens. Both P. oculifer and P. geometricus are sexually dimorphic and differences between the two species could indicate environmental or sexual selection effects, or a combination of the two. The shorter bridge length, which allowed more leg space, and wider front feet in P. oculifer cohorts probably represent traits for manoeuvring in a sandy habitat, while wider heads in P. oculifer possibly relate to interspecific differences in diet. The flatter shell in female P. oculifer, relative to P. geometricus, may represent a trade-off between space for reproductive structures, e.g., eggs, and the need to fit into small refuges, e.g., mammal burrows. Male P. oculifer had wider shells, more space around their hind legs, and wider hind feet than P. geometricus males had, all characteristics which may assist males to fight and mate in a sandy environment.</p>

The short-term temperature-response of dark respiration may be altered by climate warming through temperature acclimation; however the role of drought in influencing thermal acclimation is not known. We hypothesized that leaf dark respiration in three dominant species of the southern oak savanna in Central Texas, Schizachyrium scoparium, Juniperus virginiana, and Quercus stellata, would respond differently to the effects of warming and intensified summer drought owing to their contrasting photosynthetic pathways, leaf habits, and drought tolerances. Furthermore, changes in respiration were predicted to be linked to alterations in leaf chemistry and structure, including leaf nitrogen and non-structural carbohydrates in response to warming and drought. Monocultures planted in replicated rainfall exclusion shelters were warmed ( 1.5 �C) and rainfall events were manipulated to intensify summer drought and augment cool season rainfall compared to the long-term mean. Both warming and drought affected the short-term temperature-response functions of dark respiration and species differed in their responses. Evidence of temperature acclimation through adjustment in Q10 (temperature sensitivity) and R10 (base rate at 10 �C) was found in S. scoparium and Q. stellata but not J. virginiana. All three species showed evidence of reduced temperature acclimation of respiration with progressive summer drought. Redistributed rainfall in J. virginiana increased respiration in midsummer compared to plants receiving the long-term mean rainfall, but differences disappeared in late summer when drought intensified. In response to rainfall events during summer drought, rates in S. scoparium increased, and the effect was greater in unwarmed compared to warmed plants. In both S. scoparium and Q. stellata, Q10 was reduced post-watering. Regression analyses of respiration against leaf N, soluble carbohydrates, and SLA revealed that relationships differed between species and temperature treatments. Respiration rates were uncoupled from changes in soluble carbohydrates in response to drought and rainfall pulses, suggesting that thermal acclimation is diminished by increasing drought stress in drying soils in contrasting tree and grass species. These findings suggest that models of respiratory carbon flux that incorporate temporal changes in respiratory temperature responses with drought and warming and unique species responses will be critical in predicting species and ecosystem-scale responses to climate change.