<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>

Diss. (sammanfattning) Umeå : Sveriges lantbruksuniv. / Härtill 4 uppsatser.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv. / Härtill 3 uppsatser.

Lic.-avh (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2006. / Härtill 3 uppsatser.

Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro / &#65279;Ao longo do século XX, poucos estudos de dendrocronologia foram desenvolvidos com espécies de ambientes tropicais, em função da crença de que as condições climáticas nessas regiões não apresentavam variações suficientemente marcantes e regulares para induzir um ritmo anual de crescimento radial. A realização de trabalhos sobre esse tema nas últimas décadas revelou que a formação de anéis de crescimento anuais nos trópicos pode estar associada a fatores diversos, como: existência de estação seca bem definida, ocorrência de inundações sazonais, respostas ao comportamento fenológico, respostas ao fotoperíodo e a ritmos endógenos. O presente estudo tem por objetivo compreender a dinâmica de crescimento radial de uma espécie da Mata Atlântica se desenvolvendo em ambiente natural. Para tanto, propôs-se: i) investigar a periodicidade da atividade cambial e dos fatores que a influenciam; ii) estimar a idade e taxa de crescimento diamétrico e iii) correlacionar os fatores ambientais com os anéis de crescimento, em indivíduos de Cedrela odorata L. Para o estudo da atividade cambial, foram obtidas amostras de caule a 1,30 m do solo, contendo periderme, faixa cambial e xilema e floema secundários, por métodos não destrutivos. A fenologia vegetativa e a frutificação dos indivíduos amostrados foram acompanhadas durante todo o período do experimento. O material coletado foi processado segundo técnicas usuais em Anatomia Vegetal e analisado sob microscopia óptica e de fluorescência. Os dados de fotoperíodo, precipitação, temperatura e fenologia vegetativa foram correlacionados à atividade cambial. Para o estudo dos anéis de crescimento, as coletas também foram realizadas a 1,30 m do solo, por meio de sonda de Pressler. As amostras obtidas foram polidas e analisadas sob microscópio estereoscópio, para demarcação e aferição do número de anéis de crescimento, e a largura dos anéis foi mensurada para a determinação das taxas de crescimento radial. A série histórica de temperatura e precipitação foi correlacionada à cronologia dos anéis de crescimento. Os resultados indicaram que a atividade cambial segue um ritmo anual de crescimento, correlacionado à sazonalidade do fotoperíodo, da precipitação e da fenologia vegetativa. A análise dos anéis de crescimento permitiu estimar a idade dos indivíduos e determinar a taxa média de incremento e as taxas de incremento diamétrico acumulado e incremento médio anual para a espécie no sítio de estudo. Os dados de incremento radial evidenciaram a ausência de relação entre a idade e o diâmetro das árvores. A análise da variação na largura dos anéis não apresentou correlações significativas com os fatores climáticos analisados. / Along the 20th century, a few dendrochronological studies were developed with tropical species, according to the belief that variations of the climatic conditions on those regions werent regular and strong enough to induce an annual rate of radial growth. The researches on this topic in the last decades showed that the formation of annual growth rings in the tropics may be associated to several factors, such as: existence of a distinct dry season, occurrence of seasonal floods and responses to photoperiod and to endogenous rhythms. The objective of this study is to comprehend radial growth dynamics of an Atlantic Rain Forest species growing in natural conditions. Therefore, it was purposed to: i) investigate the periodicity of cambial activity and its influencing factors; ii) estimate age and diameter growth rates and correlate the environmental factors with the growth rings, in Cedrela odorata L. trees. For the cambial activity study, stem samples containing periderm, cambial zone, secondary xylem and phloem were taken at 1.30 m from ground level, by nondestructive methods. Vegetative phenology and fruiting of the selected trees were monitored during the whole experiment period. The samples were processed with usual Plant Anatomy techniques and were analyzed under light and fluorescence microscopy. Photoperiod, precipitation, temperature and vegetative phenology data were correlated to cambial activity. For the growth ring study, the samples were also taken at 1,30 m from ground level, with increment borer. The samples were polished and analyzed with stereomicroscope, for the demarcation and counting of growth rings, and its length was measured for the determination of the radial growth rates. The historical temperature and precipitation data were correlated to the chronology of the growth rings. The results indicated that cambial activity follows an annual growth rhythm correlated to the seasonality of photoperiod, precipitation and vegetative phenology. The growth ring analysis allowed to estimate the age of the trees and to determine the mean increment rate, the accumulated diameter increment and the annual mean increment of the species in the study site. The radial increment data showed the absence of a relation between trees age and diameter. The variation of the rings length didnt show significant correlations with the analyzed climatic factors.

Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro / &#65279;Ao longo do século XX, poucos estudos de dendrocronologia foram desenvolvidos com espécies de ambientes tropicais, em função da crença de que as condições climáticas nessas regiões não apresentavam variações suficientemente marcantes e regulares para induzir um ritmo anual de crescimento radial. A realização de trabalhos sobre esse tema nas últimas décadas revelou que a formação de anéis de crescimento anuais nos trópicos pode estar associada a fatores diversos, como: existência de estação seca bem definida, ocorrência de inundações sazonais, respostas ao comportamento fenológico, respostas ao fotoperíodo e a ritmos endógenos. O presente estudo tem por objetivo compreender a dinâmica de crescimento radial de uma espécie da Mata Atlântica se desenvolvendo em ambiente natural. Para tanto, propôs-se: i) investigar a periodicidade da atividade cambial e dos fatores que a influenciam; ii) estimar a idade e taxa de crescimento diamétrico e iii) correlacionar os fatores ambientais com os anéis de crescimento, em indivíduos de Cedrela odorata L. Para o estudo da atividade cambial, foram obtidas amostras de caule a 1,30 m do solo, contendo periderme, faixa cambial e xilema e floema secundários, por métodos não destrutivos. A fenologia vegetativa e a frutificação dos indivíduos amostrados foram acompanhadas durante todo o período do experimento. O material coletado foi processado segundo técnicas usuais em Anatomia Vegetal e analisado sob microscopia óptica e de fluorescência. Os dados de fotoperíodo, precipitação, temperatura e fenologia vegetativa foram correlacionados à atividade cambial. Para o estudo dos anéis de crescimento, as coletas também foram realizadas a 1,30 m do solo, por meio de sonda de Pressler. As amostras obtidas foram polidas e analisadas sob microscópio estereoscópio, para demarcação e aferição do número de anéis de crescimento, e a largura dos anéis foi mensurada para a determinação das taxas de crescimento radial. A série histórica de temperatura e precipitação foi correlacionada à cronologia dos anéis de crescimento. Os resultados indicaram que a atividade cambial segue um ritmo anual de crescimento, correlacionado à sazonalidade do fotoperíodo, da precipitação e da fenologia vegetativa. A análise dos anéis de crescimento permitiu estimar a idade dos indivíduos e determinar a taxa média de incremento e as taxas de incremento diamétrico acumulado e incremento médio anual para a espécie no sítio de estudo. Os dados de incremento radial evidenciaram a ausência de relação entre a idade e o diâmetro das árvores. A análise da variação na largura dos anéis não apresentou correlações significativas com os fatores climáticos analisados. / Along the 20th century, a few dendrochronological studies were developed with tropical species, according to the belief that variations of the climatic conditions on those regions werent regular and strong enough to induce an annual rate of radial growth. The researches on this topic in the last decades showed that the formation of annual growth rings in the tropics may be associated to several factors, such as: existence of a distinct dry season, occurrence of seasonal floods and responses to photoperiod and to endogenous rhythms. The objective of this study is to comprehend radial growth dynamics of an Atlantic Rain Forest species growing in natural conditions. Therefore, it was purposed to: i) investigate the periodicity of cambial activity and its influencing factors; ii) estimate age and diameter growth rates and correlate the environmental factors with the growth rings, in Cedrela odorata L. trees. For the cambial activity study, stem samples containing periderm, cambial zone, secondary xylem and phloem were taken at 1.30 m from ground level, by nondestructive methods. Vegetative phenology and fruiting of the selected trees were monitored during the whole experiment period. The samples were processed with usual Plant Anatomy techniques and were analyzed under light and fluorescence microscopy. Photoperiod, precipitation, temperature and vegetative phenology data were correlated to cambial activity. For the growth ring study, the samples were also taken at 1,30 m from ground level, with increment borer. The samples were polished and analyzed with stereomicroscope, for the demarcation and counting of growth rings, and its length was measured for the determination of the radial growth rates. The historical temperature and precipitation data were correlated to the chronology of the growth rings. The results indicated that cambial activity follows an annual growth rhythm correlated to the seasonality of photoperiod, precipitation and vegetative phenology. The growth ring analysis allowed to estimate the age of the trees and to determine the mean increment rate, the accumulated diameter increment and the annual mean increment of the species in the study site. The radial increment data showed the absence of a relation between trees age and diameter. The variation of the rings length didnt show significant correlations with the analyzed climatic factors.

Philosophiae Doctor - PhD (Biodiversity and Conservation Biology) / Southern Africa harbours one-third of the world'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 – 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. 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: 0.7–306 ha for minimum convex polygons and 0.7–181 ha for 95% fixed kernel estimates. The ability to 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 ‘cool-adapted’ 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. / South Africa

Introdução e objetivos Apesar de ser um importante componente estrutural de florestas tropicais e causar impactos na dinâmica e funcionamento destas florestas, pouco se sabe sobre a sazonalidade do crescimento de lianas em seu ambiente natural. Lianas ainda possuem uma rica diversidade de arranjos de tecidos vasculares em seus caules devido à presença de variações cambiais. Neste contexto, o presente trabalho teve como objetivo analisar a sazonalidade da atividade cambial e da diferenciação do xilema de três espécies de lianas pertencentes a famílias com maior diversidade do hábito nos neotrópicos e com diferentes configurações em seus sistemas vasculares caulinares, Stizophyllum riparium (Bignoniaceae), Dalbergia frutescens (Leguminosae) e Serjania laruotteana (Sapindaceae), bem como verificar se há relação entre a sazonalidade da atividade cambial e a sazonalidade da pluviosidade; e se há a formação de camadas de crescimento anuais no xilema. Métodos A sazonalidade da atividade cambial e da diferenciação do xilema foi estudada através de coletas periódicas de porções caulinares ao longo de um ano, correlacionando-se esses dados com a pluviosidade. Resultados As três espécies apresentaram sazonalidade nas suas atividades cambiais, correlacionada com a pluviosidade. S. riparium e D. frutescens apresentam um período de atividade cambial de cerca de seis meses, com início no pico do período chuvoso, e um período de dormência no resto do ano. S. laruotteana apresenta atividade cambial contínua ao longo do ano, com um pico de atividade relacionado com o período chuvoso. O câmbio não apresenta atividade contínua por toda sua extensão nas três espécies, sendo que as variações cambiais de S. riparium e S. laruotteana tem grande influência, respectivamente, sobre as regiões onde a atividade cambial se inicia e tem maior intensidade. Camadas de crescimento anuais são formadas no xilema secundário de S. riparium e S. laruotteana. Quando a atividade cambial não se estende por toda circunferência do caule, camadas de crescimento confluentes são formadas. Conclusões A espécies apresentam sazonalidade na atividade cambial correlacionada com a pluviosidade. Entretanto, os diferentes padrões de atividade cambial encontrados são espécie-específicos, e não podem ser explicados apenas pela pluviosidade / Background and aims Although being an important structural component of tropical forests and cause impacts on the dynamics and function of these forests, little is known about the growth seasonality of lianas growing in its natural environment. Lianas also present huge secondary vascular tissue diversity in its stems due the presence of cambial variation. In this context, the aim of the present work is to analyze the cambial activity seasonality of three liana species belonging to the most diverse liana families in the Neotropics, and which presents different patterns of vascular system configurations in their stems, Stizophyllum riparium (Bignoniaceae), Dalbergia frutescens (Legumosae), and Serjania laruotteana (Sapindaceae), and also verify possible correlations between the cambial activity and the pluviosity, and if there are formation of annual growth rings in the species xylem. Methods The seasonality of cambial activity and differentiation of xylem was studied by periodic collecting stem portions over a year, correlating this data with the rainfall. Key results The three species showed seasonality in their cambial activities, correlated with rainfall. S. riparium and D. frutescens have a period of cambial activity of about six months, beginning at the peak of the rainy season, and a period of dormancy during the rest of the year. S. laruotteana has a continuous cambial activity throughout the year, with a peak of activity related to the rainy season. The cambium does not present continuous activity throughout its circumference in the three species, and in S. riparium and S. laruotteana the cambial variants have a great influence on the regions where cambial activity starts and it has a greater intensity, respectively. Annual growth layers are formed in the secondary xylem of S. riparium and S. laruotteana. When the cambial activity does not extend throughout the circumference of the stem, confluent growth layers are formed. Conclusions The species show seasonality in cambial activity correlated with rainfall. However, the different patterns of cambial activity found are species-specific, and can not be explained only by rainfall

Ten ring-width based chronologies from Nepal are described and the prospects for further dendroclimatic work there reviewed briefly. The initial results are encouraging, and more intensive subregional sampling is called for. All the cores examined showed distinct annual rings, and there was little evidence of double or missing rings, except juniper at some sites and in some Pinus roxburghii trees. Difficulty was encountered in dating Pinus wallichiana and Cupressus dumosa. Individual site chronologies of Cedros deodora, P. roxburghii and P. wallichiana were particularly promising, and of high elevation Abies spectabilis moderately so. Densitometric data are likely to be more useful for this species. The paucity of meteorological data in Nepal represents an obstacle to further dendroclimatic work there.

The relationships between the tree-rings of the white fir (Abies alba Mill.) and climate in the French internal Alps are indicated by correlation functions. This fir shows an accurate response to climate as well as long term persistence for at least six years (MS =0.18, R1 =0.65, and R6= 0.27). Its growth is strongly influenced by the previous year's climate, especially by prior August rainfall, which enhances ring size, or by high temperatures, which show the opposite effect. The most critical period extends from prior July to prior September. This species responds positively to warm temperature from current January to April, followed by rainfall in May and June, which leads to a longer growth period. A favorable water balance seems to be decisive. Abies alba can be affected by frost and seems to prefer a low thermal amplitude as demonstrated by the analysis of the extreme temperature data. Moreover, even a few days of excessive heat can reduce its growth.