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1.
Fox, V.E., Lindeque, P.M., Simmons, R.E., Berry, H.H., Brain, C. & Braby, R. 1997. Flamingo ‘rescue’ in Etosha National Park, 1994: technical, conservation and economic considerations. Ostrich 68 (2–4): 72–76.

During April 1994,144 Greater Flamingo Phoenicopterus ruber chicks were taken from Etosha Pan, Namibia, following drying of the shallow water and the death of hundreds of chicks. The captured chicks ranged from approximately 2 weeks to 2 months of age and were hand-reared at Okaukuejo until being released (7 weeks later) or sold (12 weeks later). Fourteen birds died within 8 days; only two died later. Of 77 chicks released at Walvis Bay, their traditional wintering grounds, 76 were fitted with yellow plastic rings and 73 with numbered metal rings. These grey juveniles were highly visible in the lagoon among the pink adults, and were resighted regularly. Most of the 20 birds recovered dead within two months of release were birds with wing chord measurements less than 315 mm, and black-backed jackal Canis mesomelas predation was the most likely cause of death. Bird counts 11 and 14 months later at Walvis Bay and surrounding wetlands revealed no juveniles at all, suggesting high mortality. However, four ringed flamingos were sighted in Jan. 1997, and one debilitated ringed flamingo was recovered at the Namibia-Botswana border in Feb. 1997. A lack of predator avoidance was thought to be the main factor responsible for the high mortalities.  相似文献   

2.
  1. Many policies and studies globally have highlighted the pivotal role of wetland ecosystems regarding wetland biota and their ecological status. With the strengthening of wetland ecosystem management legislation and policy, wetland restoration should also consider increasing habitat diversity to improve biota. We explore whether the construction of artificial ecological islands can increase the diversity of and macroinvertebrates before assessing the effects of actively constructing islands via human intervention on wetland protection.
  2. We discuss changes in macroinvertebrate diversity (i) with and without islands, (ii) at different water‐level gradients surrounding the islands, (ⅲ) on different island substrates, and (ⅳ) at different time scales. We used ANOVA, ANOSIM, and cluster analysis to test the differences.
  3. The macroinvertebrate communities had spatially heterogeneous distributions which changes over time due to both natural and anthropogenic stresses. The establishment of islands significantly increased the community composition and biodiversity of the macroinvertebrate. Water depth and substrate affect community composition of macrozoobenthos. The abundance and diversity of macroinvertebrates can influence the biodiversity of their predators (fish and waterbirds). Potentially, the construction of islands could provide some cobenefits for the conservation of wetland fauna.
Synthesis and applications. Establishing artificial ecological islands in broad open‐water areas and increasing water‐level gradient and substrate diversity can increase microhabitat availability and habitat heterogeneity. These changes can adapt to different ecological niches of aquatic organisms, increase biodiversity, and have a positive effect on the ecological restoration of inland freshwater marshes and wetlands.  相似文献   

3.
Why are Dormice rare? A case study in conservation biology   总被引:4,自引:0,他引:4  
In the last 100 years, the Dormouse Muscardinus avellcmarius has disappeared from about half its geographical range in Britain. Evidence is presented which indicates that declining range and numbers are due to a complex interplay of factors which include fragmentation, deterioration and loss of specialized habitat. The Dormouse is unusual in being a relatively A-selected small mammal, with exacting ecological requirements which render it very vulnerable, particularly to habitat fragmentation. The Dormouse is also sensitive to climate, both directly and probably indirectly through the effects of weather on the timing and abundance of food (insects, flowers and fruits). Combined with low population density and low intrinsic rate of population increase, this makes the Dormouse highly vulnerable, not just to absolute climatic measures (e.g. temperature, rainfall), but especially to climatic stochasticity, particularly at the edge of its range. There are strong associations between the distribution and changing status of the Dormouse and various climatic parameters, and clear parallels with other climate-sensitive taxa, notably bats and butterflies.
The Dormouse is a very specialized species, highly sensitive to environmental change, resulting in its piecemeal, progressive extinction, particularly in northern counties. It is likely to be a very sensitive indicator species for monitoring future changing environments and an excellent model for studying the effects of habitat fragmentation, climatic shifts and climatic stochasticity.  相似文献   

4.
Dominance relationships of female sooty mangabeys have thus far been studied exclusively in captive groups. In captivity, adult females form a stable linear hierarchy as would be expected in species exhibiting strong contest competition. However, the same individuals do not exhibit other aspects of behavior that would be expected where contest competition occurs. For example, they show no kin‐based alliances leading to hierarchies in which the members of each matriline occupy adjacent ranks. The goal of this study was to provide the first data on dominance relationships of sooty mangabey females in their natural environment in the Taï National Park, Ivory Coast. In our study group, adult females formed a linear dominance hierarchy. Aggression over food increased in food patches, as would be expected for species that experience contest competition. Moreover, females formed highly differentiated social relationships, showing particular affinities with females of adjacent rank. Am. J. Primatol. 56:137–153, 2002. © 2002 Wiley‐Liss, Inc.  相似文献   

5.
Slovenia has one of the most extensive Natura 2000 networks in Europe with 259 SAC’s covering 31.4% of the country. To determine how well does the current network cover the areas of high butterfly diversity and/or aggregation of the butterfly species of conservation concern, the data from the recent survey for a distribution atlas were used. Altogether 99,423 records of 173 species collated after 1979 were used. The data distribution is slightly biased towards SAC’s, with 44.8% of localities within them, most likely due to sparsely sampled urban areas and intensive farmland areas which are found only outside SAC’s. The diversity and distribution of red listed species was evaluated at a 5 × 5 km grid square level. Additionally the importance of the size of the SAC’s was compared to their butterfly species diversity. In general the high diversity areas also hold the largest aggregation of red listed species with core areas concentrated in SW Slovenia. The SAC’s cover majority of areas with high diversity and the distribution of all but one threatened butterfly species. That species is Colias myrmidone, which is now considered extinct in Slovenia with no records after 1993. The most prominent areas with high conservation value in Slovenia not included in the SAC’s network are the Koro?ka region, Gori?ka Brda region, lower Sava River valley and Slovenske Gorice region. The butterfly diversity in small SAC’s is relatively high with increases in size only gradually increasing the species numbers, thus emphasizing the importance and conservation value of small SAC’s for sustaining high butterfly diversity in Slovenia.  相似文献   

6.
7.
We review published studies to show that changes in soil moisture levels have significant impacts on a range of wading bird species that use UK lowland grassland, including wet grassland, and obtain their food predominantly by probing the soil. We examine both the hydrological and the ecological literature and assess how management options could alter (1) ecosystem services (via water quality and flooding) and (2) habitat quality for wading birds. The combination of biodiversity goals with broader ecosystem services has been widely advocated and we suggest that appropriate management at multiple scales (e.g. small‐scale: ponds; large‐scale: integrated washlands) could potentially provide both ecosystem services and habitat for wading grassland birds. However, there is only a limited base of evidence on which to assess the potential linkage between these two areas, particularly for non‐wading bird species. Future work should be directed at identifying (1) how crop yield, ecosystem services and biodiversity relate to each other, (2) the extent of land needed to be managed to benefit these multiple purposes and bring about measurable gain (e.g. one or two ponds may make significant inroads in reducing run‐off and pollution but make little difference to wading birds) and (3) solutions to the challenges of setting up management options at large spatial scales (e.g. catchments).  相似文献   

8.
This article examines how the rise of planning in conservation influences the conservation practitioners’ approach to conflicts in a region where protected areas have limited power. It is based on an analysis of the management plans of ten nature reserves of the Northern French Alps, complemented with interviews with the practitioners involved in elaborating these plans. It shows that the collaborative paradigm, predicated on the idea that deliberation between parties can lead to a shared understanding of the common good, has pervaded conservation planning. Collaborative planning enriches the planners’ view of the practices and values at work in the reserves. But it also encourages them to develop conflict avoiding strategies that contribute to maintaining existing power imbalances, which in such regions are often detrimental to conservation goals. Analysing the power relationships at play locally, encouraging the planners’ reflexivity, and increasing their agency would help realize the transformative potential of contentious situations.  相似文献   

9.
Up until the present, canals and ditches in Europe have been used to drain and thus devastate fens (lowland moors). However, in many cases, their function can be changed from drainage to irrigation and re-wetting of previously drained areas. These systems of canals and ditches are characteristic elements of the historically developed cultural landscape. Therefore, management and development plans should be oriented towards their continual maintenance. Despite the density of canals and ditches in many regions of Germany, especially of Eastern Germany, there are only a few studies to evaluate these systems of waterways, and an integrated approach towards their assessment has been totally absent. Existing approaches for typology and assessment of flowing waterbodies have been investigated in the Drömling Natural Park with regard to their applicability to such artificial canals and ditches. Special attention is given to the composition of macroinvertebrate fauna and the assessment of factors that determine it. Surprisingly, most water sectors have a high conservation value. High total numbers of species correlated well with the occurrence of endangered species. p ]Among the macroinvertebrates, limnophil and phytophil species were dominant, but rheophil fauna were also commonly present. This was caused by the intermediate status of canals and ditches, since they are neither completely flowing nor completely stagnant waterbodies. Habitat quality of these waters is determined by a small number of morphological parameters: bank steepness, depth of bottom, substrate diversity, hydraulic structures, and the structure of surroundings. In the framework of management and development measures, they should be maintained and improved for the future. To assess water quality, the Saprobic index and the Chemical index were appropriate, but for indication of trophic status, the Macrophyte-trophic index was adequate. Estimation of ecological integrity by a multimetric index using macroinvertebrates indicates that waterbodies are in a good status according to the demands of the European Water Framework Directive.  相似文献   

10.
This study investigated the use of chitosan-N-acetylcysteine (NAC) as a non-viral gene carrier. In particular, we aimed to elucidate whether the advantage of thiolation was more pronounced in the stabilization of particles or in the effect of nonspecific sulfhydryl reduction of the target cells. Low-viscosity chitosan was modified by covalent binding of NAC. The resulting conjugate displayed 1.35 mM SH/g polymer. Particles produced via self-assembly of chitosan conjugate and pDNA had a mean particle size of 113.7 nm and a positive zeta-potential. Sulfhydryl group content on the particle surface was investigated by Ellman's test and papain reactivation assay, with the result of about 100 nM SH groups/mL nanoparticle suspension. An oxidation step was performed to stabilize polyplexes via disulfide bonds. The enhanced stability of oxidized particles against both polyanion heparin and alkaline pH was proven by a gel retardation assay. The stabilization was demonstrated to be reversible by treatment with glutathione. Further, the effect of immobilized SH groups and of supplementation with free NAC on transfection efficacy on Caco-2 cells was investigated. The expression of the transgene was raised 2.5-fold and 10-fold with nonoxidized thiomer polyplexes in comparison to polyplexes of unmodified chitosan and oxidized chitosan-NAC, respectively. The impact of sulfhydryl reduction on transfection was assessed via thiol group inactivation with 5,5'-dithiobis-(2-nitrobenzoic acid) (DNTB). This inactivation resulted in a decrease of transfection efficacy. In conclusion, chitosan-NAC conjugate was demonstrated to be beneficial for transfection, either for stabilization via disulfide bonds or for raising the expression of transgene via shifting the redox potential of the target cells.  相似文献   

11.
Jaguars and pumas are the largest felids in the Americas. Information about these two species is scarce, especially where both species are sympatric. We studied the use and selection of macrohabitats, spatial segregation and kinship in jaguars and pumas in the Viruá National Park (Amazonian lowlands) by non-invasive genetic analyses of faecal samples. Seven different jaguars (six males and one female) and nine different pumas (five males and four females) were identified. We found space use segregation between the two species, with pumas using mostly forested habitats and jaguars using open habitats slightly more than the forested ones. This result is unexpected, since previous studies have found that pumas favour more open habitats than jaguars. The results suggest that jaguars use the areas in a more random manner, corresponding to the habits of a dominant generalist species, whereas pumas use the area to reduce encounter rates with jaguars. Nevertheless, both species mainly used areas near upland forest-flooding habitats. Some kinship categories were supported with a p < 0.05 in 57 and 83% of the pair comparisons between the identified jaguars and the identified pumas, respectively. Non-invasive genetic analysis of faeces was useful to study the spatial ecology of solitary, rare and cryptic species in the Amazon.  相似文献   

12.
13.
Whether polygyny is harmful for women and their children is a long-standing question in anthropology. Few studies, however, have explored whether the effect of polygyny varies for women of different wife order, and whether there are different outcomes for their sons and daughters. Because males have higher reproductive variance, especially when they are allowed to take multiple wives, parents may have higher fitness returns from investing in sons over daughters in polygynous households. Moreover, previous studies have found that first wives and their children are advantaged over monogamous and second order wives (who marry into unions later). Here we test the predictions that children of first wives will have an advantage over children to monogamous or second wives, and that sex-biased investment will be strongest among first wives. Using data from the Arsi Oromo of Ethiopia (n ~ 6200 children) we test whether associations with mother's wife order extend beyond childhood into adulthood by examining simultaneously child survival, education and age at marriage. We find that polygynous first wives have no child survival disadvantage, first wives' sons benefit in terms of longer education and daughters have an earlier age at marriage than daughters of monogamous women. Second wives have lower child survival than monogamous women, but surviving children experience advantages in later life outcomes, particularly marriage. These findings challenge the view that polygynous women are always doing the ‘best of a bad job’. Rather, our results suggest that via their surviving sons and daughters there may be long-term benefits for some polygynous women.  相似文献   

14.
Effective vegetation classification schemes identify the processes determining species assemblages and support the management of protected areas. They can also provide a framework for ecological research. In the tropics, elevation‐based classifications dominate over alternatives such as river catchments. Given the existence of floristic data for many localities, we ask how useful floristic data are for developing classification schemes in species‐rich tropical landscapes and whether floristic data provide support for classification by river catchment. We analyzed the distribution of vascular plant species within 141 plots across an elevation gradient of 130 to 3200 m asl within La Amistad National Park. We tested the hypothesis that river catchment, combined with elevation, explains much of the variation in species composition. We found that annual mean temperature, elevation, and river catchment variables best explained the variation within local species communities. However, only plots in high‐elevation oak forest and Páramo were distinct from those in low‐ and mid‐elevation zones. Beta diversity did not significantly differ in plots grouped by elevation zones, except for low‐elevation forest, although it did differ between river catchments. None of the analyses identified discrete vegetation assemblages within mid‐elevation (700–2600 m asl) plots. Our analysis supports the hypothesis that river catchment can be an alternative means for classifying tropical forest assemblages in conservation settings.  相似文献   

15.
The importance of the values underlying different concepts of biodiversity conservation and landscape planning is increasingly recognised, and yet these value judgements of the public and of experts are still poorly understood. Although landscape and conservation management are closely interrelated and measures in one field are likely to have effects on the other, the relationship between biodiversity and conservation values on the one hand, and landscape preferences on the other hand, has been hardly explored so far. This study represents a first attempt to empirically examine this relationship from an integrated perspective, considering philosophical, ecological and economic aspects and using items focused on biodiversity. We used a quantitative survey of the general Swiss population with visualisations of potential landscape developments in the Swiss Alps and items related to biodiversity- and conservation-values. Our research shows that respondents who prefer reforested landscapes tend to be more concerned about the conservation of species, landscapes, and natural processes than people preferring cultural landscapes. Respondents who prefer cultural landscapes are more oriented towards utilitarian values and are overrepresented in mountain areas as compared to the lowlands, thus in areas that are more likely to become the target of conservation measures. Our findings have practical implications for conservation in Switzerland and other mountainous areas, particularly in times of agricultural decline and land abandonment and their associated changes in landscape and biodiversity.  相似文献   

16.
Aim Data shortages mean that conservation priorities can be highly sensitive to historical patterns of exploration. Here, we investigate the potential of regionally focussed species distribution models to elucidate fine‐scale patterns of richness, rarity and endemism. Location Eastern Arc Mountains, Tanzania and Kenya. Methods Generalized additive models and land cover data are used to estimate the distributions of 452 forest plant taxa (trees, lianas, shrubs and herbs). Presence records from a newly compiled database are regressed against environmental variables in a stepwise multimodel. Estimates of occurrence in forest patches are collated across target groups and analysed alongside inventory‐based estimates of conservation priority. Results Predicted richness is higher than observed richness, with the biggest disparities in regions that have had the least research. North Pare and Nguu in particular are predicted to be more important than the inventory data suggest. Environmental conditions in parts of Nguru could support as many range‐restricted and endemic taxa as Uluguru, although realized niches are subject to unknown colonization histories. Concentrations of rare plants are especially high in the Usambaras, a pattern mediated in models by moisture indices, whilst overall richness is better explained by temperature gradients. Tree data dominate the botanical inventory; we find that priorities based on other growth forms might favour the mountains in a different order. Main conclusions Distribution models can provide conservation planning with high‐resolution estimates of richness in well‐researched areas, and predictive estimates of conservation importance elsewhere. Spatial and taxonomic biases in the data are essential considerations, as is the spatial scale used for models. We caution that predictive estimates are most uncertain for the species of highest conservation concern, and advocate using models and targeted field assessments iteratively to refine our understanding of which areas should be prioritised for conservation.  相似文献   

17.
Climate change is expected to challenge forest management and nature conservation in forests. Besides forest species, strategies and references for management and conservation will be affected. In this paper, we qualitatively analysed whether forest conservation and management practice have already adapted to the impacts of climate change and to what extent those practices reflect the adaptation strategies dealt with in international peer-reviewed literature. To this end, we conducted thirteen in-depth interviews with forest practitioners (forest officers/forest district officers) in four regions in Germany. The interview regions were selected to represent the variation in tree species composition, forest ownership regimes and vulnerability to climate change. Although interviewees claimed to take climate change and adaptation strategies into account, in practice such strategies have as yet only occasionally been implemented. Our results suggest that strategies for adapting forest management to climate change are just in the early stages of development or supplement existing strategies relating to general risk reduction or nature-orientated forest management. The extent to which climate change adaptation strategies have influenced overall management varies. This variation and the lack of specific strategies also reflect the existing uncertainties about future changes in climate and about the capacity of forest ecosystems to adapt. We conclude that, in the face of climate change, forest management will have a major influence on future biodiversity composition of forest ecosystems. Hence, a framework for conservation in forests providing recommendations which also take into account the consequences of climate change needs to be developed.  相似文献   

18.
Areas set apart for nature conservation in Britain are broadly categorised according to their cultural purpose, and names are assigned to these in this paper. Nature reserves may be similar to zoos and botanic gardens in aiming to maintain the diversity of species and if so are termed biodiversity reserves. This tradition understands nature as a static collection of entities apart from humans. Maintaining traditional management at a site is arguably a good way to sustain species, it also retains old ways in which humans and nature were integrated in the life of the nation and so are called historic countryside parks. There is growing interest in wilderness areas, where nature is seen as primarily processes protected from human interference. Despite the strength of each of these, they suffer from attempting to restrict nature to a ghetto, a process that is economically and environmentally costly. Companion places are places which set sustainable examples of integrating human life and economic activity with maintaining biodiversity and offering an opportunity to encounter wild processes at the heart of life. The language of these four types, or vectors, of nature reserves is offered to help the discussion of our place in nature.  相似文献   

19.
Aim To test the prediction that environmental suitability derived from species distribution modelling (SDM) could be a surrogate for jaguar local population density estimates. Location Americas. Methods We used 1409 occurrence records of jaguars to model the distribution of the species using 11 SDM methods. We tested whether models’ suitability is linearly correlated with jaguar population densities estimated from 37 different locations. We evaluated whether the relationship between density and suitability forms a constraint envelope, in which higher densities are found mainly in regions with high suitability, whereas low densities can occur in regions with variable suitability. We tested this using heteroscedasticity test and quantile regressions. Results A positive linear relationship between suitability and jaguar density was found only for four methods [bioclimatic envelope (BIOCLIM), genetic algorithm for rule set production (GARP), maximum entropy (Maxent) and generalized boosting models (GBM)], but with weak explanatory power. BIOCLIM showed the strongest relationship. Variance of suitability for lower densities values was larger than for higher values for many of the SDM models used, but the quantile regression was significantly positive only for BIOCLIM and random forests (RF). RF and GBM provided the most accurate models when measured with the standard SDM evaluation metrics, but possess poor relationship with local density estimates. Main conclusions Results indicate that the relationship between density and suitability could be better described as a triangular constraint envelope than by a straight positive relationship, and some of the SDM methods tested here were able to discriminate regions with high or low local population densities. Low jaguar densities can occur in areas with low or high suitability, whereas high values are restricted to areas where the suitability is greater. In high suitability areas but with low jaguar density estimates, we discuss how extrinsic factors driving abundance could act at local scales and then prevent higher densities that would be expected by the favourable regional environmental conditions.  相似文献   

20.
Abstract. An entomological inventory was conducted between 1993 and 1996 to obtain information on the diversity of mosquitoes (Diptera: Culicidae) in the Jaú National Park, State of Amazonas, Brazil. A total of 10,159 adult (91%) and immature mosquito specimens, representing 130 taxa (species + morphospecies) in 16 genera, was collected. A species list for the family Culicidae is presented, including 30 new records for the State of Amazonas. The collecting localities were restricted to the alluvial subregion of the Open Tropical Forest found in the park. Most of the specimens (71%) were collected in forest habitats and the rest in areas of second growth and peridomicile. The majority of immature specimens (46%) were collected in bodies of water along the edges of rivers, flooded forests, lakes and streams. Among the various collection methods used, the Centre for Disease Control (CDC) and Shannon traps together were responsible for capturing 60% of the adults. More than 90% of the material collected belongs to the genera Culex (65%), Psorophora (19%), Wyeomyia (4%), and Anopheles (3%), which together represent 70% of the identified taxa. The genus Culex presented the largest number of species (45). The species Culex (Melanoconion) vaxus, Cx. (Mel.) pedroi, Psorophora amazonica, Cx. (Mel.) portesi and Cx. (Mel.) theobaldi together (< 4% of the recorded species) represent more than 63% of the material collected and identified to the species level. The most abundant species was Cx. (Mel.) vaxus, representing 17% of the material identified to species. The possible epidemiological and ecological implications of the species hereby recorded in the Jaú National Park are presented and discussed.  相似文献   

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