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Mature Individuals (mature + individual)
Selected AbstractsDemographic genetics of American beech (Fagus grandifolia Ehrh.) IV.PLANT SPECIES BIOLOGY, Issue 3 2008Development of genetic variability, gene flow during succession in a coastal plain forest in Maryland Abstract Genetic recovery of an American beech (Fagus grandifolia) population in deciduous forests that were once pastures was studied using 16 allozyme loci from 410 individuals in a 600 m × 600 m study plot in Maryland, USA. We also examined the spatio-temporal genetic structure of the American beech population at a regional scale. Overall genetic diversity of mature trees was measured by estimating average heterozygosity (H = 0.156). Rare alleles were observed in five loci, Lap, 6Pdgh3, Pgi, Adh1 and Got3. Mature individuals were divided into three size classes based on d.b.h. The genetic component of each size class was compared and it was revealed that several alleles (Pgm-a, 6Pgdh3-a and Lap-b) were shared only in specific size classes. The spatial distribution of the genotypes demonstrated a conspicuous localization in three loci (Aco, Adh1 and Idh). Spatial autocorrelation analyses were carried out among the mature trees for a 20 m interval, and were positive for 0,120 m and negative for >180 m. Distrograms indicated that a unique genetic localization occurs among mature individuals. Seven hundred and seventy-five seedlings in the 10 m × 120 m transect were analyzed to measure gene flow via seed and/or pollen. We obtained a genetic neighborhood area of 1.17 ha and an effective population size of 32.4. The temporal and spatial modes of genetic recovery of the population are discussed in the context of conservation biology. [source] Population ecology of cave armoured catfish, Ancistrus cryptophthalmus Reis 1987, from central Brazil (Siluriformes: Loricariidae)ECOLOGY OF FRESHWATER FISH, Issue 2 2007E. Trajano Abstract,,, The population ecology of Ancistrus cryptophthalmus (Reis 1987) was studied by mark,recapture technique in caves from the São Domingos karst area, State of Goiás, northeastern Brazil. Total population sizes estimated for Angélica and Passa Três Caves were 20,000 and 1000 individuals, respectively. Densities around 1.0 individuals per m2 in Angélica, Bezerra and São Vicente I Streams, and 0.6 individuals per m2 in the smaller Passa Três Stream may be considered high for cavefish standards, as well as for epigean loricariids. As expected for benthic grazers, cave catfish are highly sedentary. The distribution of size classes did not differ among caves and within the same cave throughout the studied dry seasons; on the contrary, the condition factor decreased throughout this period probably because of the progressive depletion of organic matter available as food. Low proportions of mature individuals, low growth rates (average = 0.5 mm month,1) with cases of negative growth and high longevities (8,10 years) point to a precocial lifestyle, typical of troglobitic species. [source] Fish community characteristics of the lower Gambia River floodplains: a study in the last major undisturbed West African riverFRESHWATER BIOLOGY, Issue 2 2009VASILIS LOUCA Summary 1.,The Gambia River is the last major West African river that has not been impounded. However, a hydroelectric dam is being constructed and substantial changes to the hydrology and ecology of the system are expected. 2.,Little information is available on the impact of water impoundments in semi-arid regions on downstream floodplain fish communities, due to the scarcity of pre-intervention data. Because profound impacts on physical habitat, salinity and nutrient transport can occur downstream of such impoundments, a knowledge of the species-habitat associations of biota such as fishes is necessary for understanding likely changes and how to limit them. 3.,Fish were sampled using cast and hand nets along two transects on the floodplain, and with fyke nets in two ,bolongs' (creeks) from May to November 2005 and 2006 in the lower reaches of the Gambia River, close to the salt water front where ecological changes due to the construction of the dam are likely to be pronounced. 4.,Greatest fish species richness was associated with low conductivity, low pH and deep water. Bolongs held greater species richness compared with other floodplain habitats, probably because they acted as conduits for fish moving on and off the floodplain. Species richness and catch biomass increased rapidly following the first rains and then declined. 5.,Using a multivariate analysis, three main species groups were identified on the floodplain; one associated with deeper water, one with less brackish water and one with shallow, open water. Tilapia guineensis was the commonest species on the floodplains. 6.,The floodplains provide nursery habitats as many fish captured were immature, particularly for species where adults are mainly encountered in the main channel. Several small-sized floodplain specialists were also represented by a high proportion of mature individuals. 7.,Impoundment is expected to reduce seasonal flooding of the floodplain in the lower Gambia River, downstream of the impoundment, resulting in reduced occurrence of aquatic habitats, especially bolongs, together with lower dissolved oxygen and increased salinity, leading to alteration of the floodplain fish communities, benefiting salt-tolerant species, reducing overall species richness and probably reducing floodplain fish production. [source] Analysis of factors that affect maternal behaviour and breeding success in great apes in captivityINTERNATIONAL ZOO YEARBOOK, Issue 1 2006M. T. ABELLO In this paper the relationship between maternal behaviour and breeding success (or failure) in great apes is described. Data were gathered from a questionnaire survey returned by 48 zoos and from available studbook data, giving a total sample size of 687 individuals [Gorillas Gorilla gorilla (n= 277), Bonobos Pan paniscus (n= 37), Chimpanzees Pan troglodytes (n= 216) and Orangutans Pongo pygmaeus (n= 157)] born between 1990 and 2000 at 86 institutions. The factors influencing maternal behaviour are discussed. Particular attention is paid to the importance of learning and experience for the development of good maternal skills. The rearing background and social-group circumstances of the breeding , were analysed, including her rearing situation (own mother, conspecific surrogate or hand-reared), opportunity (or not) to observe maternal behaviour in conspecifics during development and previous breeding experience. The effects of maternal training are also analysed. The results show that for a , great ape to demonstrate good maternal skills, the most effective experience is to have been reared by her own mother and to have observed maternal behaviour in a social group comprising mature individuals and infants. This gives ,, the opportunity to observe and learn how to care adequately for their own offspring. [source] Globally threatened parrots: criteria, characteristics and curesINTERNATIONAL ZOO YEARBOOK, Issue 1 2000N.J. COLLAR Ninety (26%) of the world's parrot species are threatened with extinction. While this figure will vary with deteriorating circumstances, taxonomic insight and assessment of new evidence, the great majority (currently 93%) of threatened parrots are forest species, most (75 species, 83%) have populations estimated at less than 10 000 mature individuals, and many (37 species, 41%) have ranges %%20 000km2. Habitat destruction (notably the loss of nest-sites), trade, hunting and introduced species are significant threats. Indonesia, Australia, Brazil, the Philippines, Colombia and Mexico support two-thirds (60 species) of all threatened parrots. Conservation of sites with sympatric threatened parrots is required, alongside research and awareness programmes that enable site and species management. [source] Cowpox virus infection in natural field vole Microtus agrestis populations: delayed density dependence and individual riskJOURNAL OF ANIMAL ECOLOGY, Issue 6 2006SARAH BURTHE Summary 1Little is known about the dynamics of pathogen (microparasite) infection in wildlife populations, and less still about sources of variation in the risk of infection. Here we present the first detailed analysis of such variation. 2Cowpox virus is an endemic sublethal pathogen circulating in populations of wild rodents. Cowpox prevalence was monitored longitudinally for 2 years, in populations of field voles exhibiting multiannual cycles of density in Kielder Forest, UK. 3The probability that available susceptible animals seroconverted in a given trap session was significantly positively related to host density with a 3-month time lag. 4Males were significantly more likely to seroconvert than females. 5Despite most infection being found in young animals (because transmission rates were generally high) mature individuals were more likely to seroconvert than immature ones, suggesting that behavioural or physiological changes associated with maturity contribute to variation in infection risk. 6Hence, these analyses confirm that there is a delayed numerical response of cowpox infection to vole density, supporting the hypothesis that endemic pathogens may play some part in shaping vole cycles. [source] Population biology of the red gurnard (Aspitrigla cuculus L.; Triglidae) in the inshore waters of Eastern Anglesey and Northwest WalesJOURNAL OF APPLIED ICHTHYOLOGY, Issue 4 2010A. L. Marriott Summary ICES has identified red gurnard Aspitrigla cuculus (L.) as a potential commercial species and recommended that monitoring programmes should be conducted to derive information on biological parameters for stock assessment purposes. In this paper, data on the population biology of red gurnard in the coastal waters of Northwest Wales and Eastern Anglesey are presented. Total length (TL) of fish sampled ranged from 15.4 to 35.0 cm (males) and 10.5 to 43.1 cm (females), with the majority of females between 20 and 30 cm TL (70.0%) and males between 20 and 30 cm TL (71.0%). TL/weight (W) relations were similar between immature and mature individuals for both sexes and between both sexes (all maturity stages combined), producing a combined data equation W = 0.005 TL3.19. Age of fish ranged from 1 to 7 years and 1 to 6 years, respectively, for females and males, with the majority of females age 3 (37%) and the majority of males age 2 (49%). The age structures of female and male red gurnards were significantly different, with the older age classes consisting predominantly of female fish. Both males and females exhibited similar asymptotic growth patterns; the combined von Bertalanffy growth function was . Instantaneous rates of total mortality were calculated as 1.13 year,1 for males and 0.98 year,1 for females. The size (L50) and age at first maturity (A50) were estimated to be 26.3 cm TL and 3.6 years for males, 28.1 cm TL and 3.5 years for females and 25.6 cm TL and 3.7 years for both sexes combined. [source] Testing the abundant-centre hypothesis using intertidal porcelain crabs along the Chilean coast: linking abundance and life-history variationJOURNAL OF BIOGEOGRAPHY, Issue 3 2010Marcelo M. Rivadeneira Abstract Aim, The abundant-centre hypothesis (ACH) is based on the assumption that physiological constraints limit populations at the edges of their distributional range, yet the geographical variation of physiological performance or life-history traits has rarely been examined. Here we examine the applicability of the ACH in a marine system by testing whether physiological predictions are reflected in large-scale variations of life-history traits. Location, The Chilean coast (18°,42° S), encompassing more than 2500 km along the Pacific coast of South America. Methods, Five porcelain crab species (Petrolisthes granulosus, Petrolisthes laevigatus, Petrolisthes tuberculatus, Petrolisthes violaceus and Allopetrolisthes angulosus) were sampled on intertidal boulder beaches at 13 sampling sites. For each species and site we evaluated: (1) relative abundance (density), (2) maximum size, (3) size at maturity, (4) sex ratio, (5) proportion of ovigerous females, and (6) presence of recruits. The shape of the spatial distribution of each trait was evaluated statistically against the prediction of four hypothetical models (normal, ramped-south, ramped-north and abundant-edge). Results, The relative abundance and life-history traits showed different spatial patterns among species. Relative abundance (across sites) was fitted by a normal model in only two species. No model fitted the spatial variation in body size and size at first maturity, which showed a slight but monotonic poleward increase in all species. Sex ratio showed a prominent hump-shaped pattern, with females prevailing in the centre of the ranges and males dominating towards the range boundaries; this pattern was statistically significant in three of the five studied species. The proportion of ovigerous females showed no clear latitudinal trends, and mature individuals were observed across most of the geographical range of the species. However, recruits tended to be absent towards the southern (poleward) boundaries of the distribution. Main conclusions, The ACH does not apply to all species equally. The link between abundance and life-history traits is complex and variable among the porcelain crab species studied. Overall, the observed patterns were consistent with the idea that equatorward boundaries might be controlled by physiological restrictions mainly affecting adult survival, whereas poleward boundaries might be shaped by limitations in reproductive output and larval survival. Our results underline the importance of incorporating ecological, physiological and life-history studies in future tests of the ACH. [source] Human settlement and baobab distribution in south-western MaliJOURNAL OF BIOGEOGRAPHY, Issue 11 2007Chris S. Duvall Abstract Aim, Human settlement establishment and reproduction of the baobab tree (Adansonia digitata) appear spatially and temporally dependent because baobabs are abundant in many settlement sites in Africa. This paper tests the spatiotemporal relationship between baobab and settlement distribution. Location, South-western Mali. Methods, In an area of 183 km2, 1240 baobabs were located and mapped, their diameters measured, and habitat characteristics recorded for each individual. All occupied (n = 9) and abandoned (n = 84) settlements were located and mapped, and occupation dates were determined through interviews. Chi-squared analysis indicated baobab habitat preferences, and bivariate point-pattern analysis tested baobab,settlement spatiotemporal independence. Results, Baobabs and human settlements are positively spatially associated at most distances and for all baobab size-class,settlement age-class pairs. However, positive spatial association is significant only at distances < 500 m, and young settlements and large baobabs are not significantly associated. Positive association between small and large baobabs is marginally significant at <300 m, but observed significance is less than that for baobab,settlement positive association. Baobab abundance is not evenly distributed across the range of habitats it occupies; recruitment is strongest in settlements and fields, and on cliffs, while mortality is highest on cliffs. Ethnographic observations suggest that human settlement practices and fruit use are the main human factors contributing to baobab,settlement positive spatial association. Main conclusions, There are three main conclusions: (1) Human settlement and baobab recruitment are spatially dependant because settlement leads directly and indirectly to the development of baobab groves at settlement sites. (2) The lower than expected abundance of mature individuals in natural habitats, and the habitat preferences of the observed population, suggest that baobabs were introduced to south-western Mali, probably centuries ago. (3) Human mobility over decadal time-scales is necessary to maintain baobab population structure in landscapes dominated by shifting land use, where baobabs are not purposefully planted. Baobab population processes in such landscapes occur at the scale of human settlement. [source] Predation by brown trout: a major mortality factor for sexually mature European minnowsJOURNAL OF FISH BIOLOGY, Issue 3 2003J. Museth Brown trout Salmo trutta in the subalpine lake, Øvre Heimdalsvatn, showed large temporal variation in the rate of predation on the introduced minnow Phoxinus phoxinus population. Minnows were found in the stomachs of brown trout between 16 and 38 cm LT. Significantly greater predation was recorded shortly after ice break at the end of June 1999, with frequencies of 9 and 20% within the LT classes 16,29·9 cm and ,30 cm, respectively. Predation on minnows was only occasionally detected during July, August and September. The high level of predation coincided with minnow spawning, and lengths of consumed minnows were equal to those of sexually mature individuals. Accepting a causal link between minnow spawning, which lasted c. 3 weeks, and the contemporary high rate of predation, the estimated annual consumption of minnows by the brown trout population would be 138 kg wet mass. Although most of the annual consumption of minnows by brown trout (90%) occurred within a very short period (3 weeks), it accounted for a significant proportion (60%) of the annual loss in biomass of the sexually mature part of the population. [source] Poverty, underdevelopment and infant mental health,JOURNAL OF PAEDIATRICS AND CHILD HEALTH, Issue 4 2003LM Richter Abstract: Very great advances have occurred in disciplinary and professional knowledge of infant development and its influence on subsequent development. This expertise includes the ways in which early experiences affect the capacity of mature individuals for social adjustment and productive competence, and promising methods of intervention to promote infant mental health and prevent adverse sequelae of risk conditions. However, very little of this knowledge has been applied in work among infants and children living in conditions of poverty and underdevelopment. This lack of application continues despite the enormous threats to the well-being of infants and young children brought about by the combined effects of poverty and the AIDS pandemic, especially in southern Africa. Protein,energy malnutrition, maternal depression, and institutional care of infants and small children are cited as illustrative of areas in which interventions, and their evaluation, are desperately needed in resource-poor countries. An argument is made for the critical importance of considering and addressing psychological factors in care givers and children in conditions of extreme material need. An example is provided of a simple intervention model based on sound developmental principles that can be implemented by trained non-professionals in conditions of poverty and underdevelopment. [source] Pharmacokinetics of flubendazole and its metabolites in lambs and adult sheep (Ovis aries)JOURNAL OF VETERINARY PHARMACOLOGY & THERAPEUTICS, Issue 6 2009Flubendazole (FLU) is indicated for control of helminthoses in pig and avian species (monogastric animals) and its corresponding pharmacokinetics are well known. The information on FLU's pharmacokinetic behavior in animal species with forestomach (ruminants) has been limited although the use of FLU in these species could be beneficial. The aim of this study was to investigate the pharmacokinetics of FLU and its main metabolites in sheep. The effects of animal age (sexually immature and mature ones) and gender were also studied. FLU was orally administered in a single experimental dose (30 mg/kg of body weight) in the form of oral suspension. Treated immature animals (aged 3 months) and 5 months later the same mature individuals (aged 8 months) were kept under the same conditions (food, water and management) and treated with FLU. Within 72 h after FLU administration, plasmatic samples were collected and FLU and its Phase I metabolites were quantified using high-performance liquid chromatography. FLU was detected in very low concentrations only, reduced FLU (FLU-R) was identified as the main metabolite, and hydrolyzed FLU (FLU-H) as the minor one. Formation of FLU-R was stereospecific with (+)-FLU-R domination. The plasmatic concentrations of (+)-FLU-R reached 10,15 times higher values than those of FLU, (,)-FLU-R and FLU-H. A significant gender effect on pharmacokinetics of FLU or (+)-FLU-R metabolite in the mature animals was found and a wide significant difference between lambs and adult sheep in FLU including both metabolites has been proved. [source] Survival of crinoid stems following decapitation: evidence from the Ordovician and palaeobiological implicationsLETHAIA, Issue 4 2001STEPHEN K. DONOVAN It was recently discovered that the stems of extant crinoids may survive after detachment of the crown, presumably feeding by the absorption of nutrients through the ectoderm. Previously, only one analogous, albeit morphologically dissimilar, pattern of crownless survival has been recognized from the fossil record. Certain Upper Ordovician (Cincinnatian) crinoid pluricolumnals from Kentucky, Ohio and Indiana, derived from the disparids Cincinnaticrinus spp., have rounded terminations reminiscent of some modern bourgueticrinid overgrowths. Such specimens have hitherto been interpreted as distal terminations of mature individuals that have become detached from their attachment structures and taken to an eleutherozoic existence. However, it is considered more probable that they represent overgrowths of the column following predatory decapitation. If this new interpretation is correct, then post-decapitation survival of crinoid stems is now recognized for most of the history of the crinoids, ,lethal' predation on crinoid crowns occurred at least as early as the Late Ordovician and ancient crinoid populations can no longer be determined merely by counting crowns. [source] Detection and visualization of spatial genetic structure in continuous Eucalyptus globulus forestMOLECULAR ECOLOGY, Issue 4 2007TIM H. JONES Abstract Visualizing the pattern of variation using microsatellites within a Eucalyptus globulus forest on the island of Tasmania provided surprising insights into the complex nature of the fine-scale spatial genetic structure that resides in these forests. We used spatial autocorrelation and principal coordinate analysis to compare fine-scale genetic structure between juvenile and mature cohorts in a study area, 140 m in diameter, located within a typical, continuous E. globulus forest. In total, 115 juvenile and 168 mature individuals were genotyped with eight highly polymorphic microsatellite loci. There was no significant difference in the level of genetic diversity between cohorts. However, there were differences in the spatial distribution of the genetic variation. Autocorrelation analysis provided clear evidence for significant spatial genetic structure in the mature cohort and significant, but weaker, structure in the juvenile cohort. The spatial interpolation of principal coordinate axes, derived from ordination of the genetic distance matrix between individuals, revealed a spatially coherent family group which was evident in both cohorts. Direct comparison of the genetic structure within each cohort allowed visualization of a shift in the spatial distribution of genetic variation within the population of approximately 10 m. As the shift coincided with the direction of prevailing winds, it is hypothesized that this phenomenon is due to downwind dispersal of seeds and is indicative of the important role of prevailing winds in forcing eastward gene flow in these high-latitude forests. [source] Demographic genetics of American beech (Fagus grandifolia Ehrh.) IV.PLANT SPECIES BIOLOGY, Issue 3 2008Development of genetic variability, gene flow during succession in a coastal plain forest in Maryland Abstract Genetic recovery of an American beech (Fagus grandifolia) population in deciduous forests that were once pastures was studied using 16 allozyme loci from 410 individuals in a 600 m × 600 m study plot in Maryland, USA. We also examined the spatio-temporal genetic structure of the American beech population at a regional scale. Overall genetic diversity of mature trees was measured by estimating average heterozygosity (H = 0.156). Rare alleles were observed in five loci, Lap, 6Pdgh3, Pgi, Adh1 and Got3. Mature individuals were divided into three size classes based on d.b.h. The genetic component of each size class was compared and it was revealed that several alleles (Pgm-a, 6Pgdh3-a and Lap-b) were shared only in specific size classes. The spatial distribution of the genotypes demonstrated a conspicuous localization in three loci (Aco, Adh1 and Idh). Spatial autocorrelation analyses were carried out among the mature trees for a 20 m interval, and were positive for 0,120 m and negative for >180 m. Distrograms indicated that a unique genetic localization occurs among mature individuals. Seven hundred and seventy-five seedlings in the 10 m × 120 m transect were analyzed to measure gene flow via seed and/or pollen. We obtained a genetic neighborhood area of 1.17 ha and an effective population size of 32.4. The temporal and spatial modes of genetic recovery of the population are discussed in the context of conservation biology. [source] Effects of food availability on serum insulin and lipid concentrations in free-ranging baboonsAMERICAN JOURNAL OF PRIMATOLOGY, Issue 1 2002Joseph W. Kemnitz Abstract The relationship between food availability and metabolic physiology was studied in groups of free-ranging baboons (Papio spp.) living in the Amboseli National Park and the Masai Mara National Reserve of Kenya. Three groups subsisted entirely on natural forage, while two other groups lived near tourist facilities and often consumed food wastes from these lodges. The refuse provided a very accessible food source with relatively high caloric density. Consumption of the refuse was associated with reduced locomotion. Sexually mature individuals from all five groups were sedated surreptitiously in the early morning and blood samples were collected. Compared to animals foraging exclusively in the wild, animals that supplemented their diet with the refuse items had two- to threefold elevations in serum insulin concentrations, as well as increased total cholesterol (C), HDL-C, and VLDL+LDL-C levels. No sex differences in physiological measures were observed except in body mass. Elevated serum insulin, and cholesterol and lipoprotein concentrations influence the development of cardiovascular disease and have been shown to be subject to dietary manipulation and exercise under controlled conditions. The present results suggest potentially deleterious effects of a highly accessible, calorically dense food source, and associated reduction of physical activity for baboons living in an otherwise natural environment. Am. J. Primatol. 57:13,19, 2002. © 2002 Wiley-Liss, Inc. [source] The Role of Soil Seed Banks in the Rehabilitation of Degraded Hillslopes in Southern Wello, Ethiopia,BIOTROPICA, Issue 1 2000Kebrom Tekle ABSTRACT The species composition in the soil seed bank of degraded hillslopes in southern Wello, Ethiopia, was assessed using the seedling emergence method and compared with that of the standing vegetation. Surface soils were sampled at 0-to 5-cm depth from 49 plots of four physiognomic vegetation classes (hereafter vegetation classes): forests, shrublands, grasslands, and degraded sites. Soils were spread on sterile sand in a glasshouse and watered. Emerging seedlings were recorded for five months until no new seedlings emerged. A total of 3969 seedlings belonging to 71 species and 30 families germinated. The species composition of the seed bank was dominated by 53 herb species (75%) compared to 2 tree species which accounted for only 3 percent of the total number of species. Seedling density differed significantly among vegetation classes and ranged from 391 to 7807 seeds/m2. Mean species richness also differed significantly among the vegetation classes. Forty-two species were found to be common to the seed banks and the standing vegetation; however, correspondence between species numbers and composition of the seed banks and the standing vegetation was poor. Although most of the species that germinated in the seed banks were herbs and grasses, they can develop a vegetative cover and contribute to reduction of soil erosion. Regeneration of the tree species (some of which have seed viability up to four years) however, requires both time and the presence of mature individuals. Together with hillside closure and soil conservation measures (e.g., terracing), planting of native woody seedlings might help to expedite rehabilitation of degraded hillslopes devoid of trees and shrubs. [source] | ||||||||||||||||