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1.
The area of the Etosha National Park in Namibia has been inhabited for many centuries by Haiǁom, a group of (now former) hunter-gatherers. In 1907, Etosha was proclaimed as a game reserve, although Haiǁom were still allowed to live in the area until they were expelled in the 1950s due to then-dominant ideas of fortress conservation. In recent years, Haiǁom have been provided with several resettlement farms by the Namibian government as a reaction to the colonial land dispossession. In this article, I explore the onto-epistemology of Haiǁom (i.e. their being in and knowing the Etosha area), focusing on their relations with the land and with human and beyond-the-human beings before their eviction. I argue that the eviction implies not only economic marginalization but also social deprivation, which is inadequately addressed with resettlement. I suggest that thinking with relations, illustrated with the Haiǁom case, would call for other solutions in the context of measures taken for past land dispossessions and would open new paths for Namibia's nature conservation initiatives.  相似文献   

2.
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   

3.
Abstract

Longitudinal data were used to examine relationships among sibling variables, perceptions of family environments, and measures of educational attainment, occupational status, and occupational aspirations. The analyses involved 21‐year‐old Australians from Anglo‐Australian, Greek, and Southern Italian families. Regression surfaces were plotted from models that included terms to test for possible linear, interaction, and curvilinear associations among the variables. The study indicated that sibsize and birth order continued to have many significant associations with young adults’ status attainment even after taking into account the mediating influence of perceived family environments. Also, the investigation suggested that there are ethnic‐group differences in relations among sibling variables, perceived parents’ support for learning, and young adults’ status attainment.  相似文献   

4.
5.
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   

6.
BackgroundThe objective of this pilot study was to assess iron (Fe), copper (Cu), zinc (Zn), and manganese (Mn) status (hair, serum, and urine) and speciation (serum) in Parkinson’s disease (PD) patients.MethodsA pilot study involving a total of 27 subjects (13 PD patients, 14 controls) was performed. Serum, urine, and hair metal content was assessed using ICP-MS. Speciation analysis of Cu, Zn, Fe, and Mn was performed using a hybrid HPLC-ICP-MS system.ResultsGroup comparisons did not reveal any significant group difference in serum Cu, Zn, Fe, and Mn total metal level between PD patients and controls. Speciation analysis revealed a significant decrease in Cu/ceruloplasmin copper in association with elevation of low-molecular weight species (amino acids)-bound copper. It is proposed that in PD, binding of Cu(II) ions to ceruloplasmin is reduced and free copper ions coordinate with low molecular weight ligands. The level of Mn-albumin complexes in PD patients was more than 4-fold higher as compared to the respective value in the control group. The observed difference may be considered as a marker of redistribution between high and low molecular weight ligands.ConclusionsMetal speciation is significantly affected in serum of PD-patients. These findings are indicative of the potential role of metal metabolism and PD pathogenesis, although the exact mechanisms of such associations require further detailed studies.  相似文献   

7.
Parasitic protists are a major cause of diarrhoeal illnesses in humans globally. Collectively, enteric pathogens exceed all other forms of infectious disease, in terms of their estimated global prevalence and socioeconomic impact. They have a disproportionately high impact on children in impoverished communities, leading to acute (diarrhoea, vomiting, dehydration and death) and chronic disease (malabsorption, malnutrition, physical and cognitive stunting and predisposition to chronic, non-communicable disease) consequences. However, historically, investment in research and disease control measures has been disproportionately poor, leading to their current classification as neglected pathogens. A sound understanding of their biology is essential in underpinning detection, treatment and control efforts. One major tool in rapidly improving our knowledge of these parasites is the use of biological systems, including ‘omic’ technologies. In recent years, these tools have shown significant success when applied to enteric protists. This review summarises much of this knowledge and highlights the significant remaining knowledge gaps. A major focus of the present review was to provide a perspective on a way forward to address these gaps using advanced biotechnologies.  相似文献   

8.
In 1937 Joseph Grinnell founded the University of California's (U.C.) first biological field station, the Hastings Natural History Reservation. Hastings became a center for field biology on the West Coast, and by 1960 it was serving as a model for the creation of additional U.C. reserves. Today, the U.C. Natural Reserve System (NRS) is the largest and most diverse network of university-based biological field stations in the world, with 36 sites covering more than 135,000 acres. This essay examines the founding of the Hastings Reservation, and asks how it managed to grow and develop, in the 1940s and 1950s, during a time of declining support for natural history research. It shows how faculty and staff courted the support of key institutional allies, presented themselves as the guardians of a venerable tradition in nature study, and emphasized the station's capacity to document ecological change and inform environmental policy and management. In the years since, Hastings and other U.C. reserves have played crucial roles in California environmental politics. Biological field stations in the post-war era deserve more attention not only from historians of biology, but also from environmental historians and other scholars interested in the role of science in society.  相似文献   

9.
BackgroundThere is an abundant link between the gut microbiota and human health and it plays a critical role in the clinic. It is recognized that microbial dysregulation contributes to the pathogenesis of tuberculosis (TB) but the underlying mechanisms remain unclear. In this study, we investigated the association of gut microbiome composition with TB as well as its possible roles in the development of this disease.MethodsFecal samples were collected from 10 TB patients and 20 healthy control samples. DNA extracted from fecal samples was subjected to 16S rDNA gene sequencing analysis on the Illumina MiSeq platform.ResultsCompared with healthy control samples, the gut microbiome of patients with TB was characterized by the decreased Alpha diversity. Perhaps, the decrease of microbial diversity which results in microbial dysregulation is the reason for clinical patients with more symptoms. The PTB group showed the most unique microbiota by higher abundance of Bifidobacteriaceae, Bifidobacteriales, Coriobacteriaceae, Coriobacteriales, Actinobacteria, Caulobacteraceae, Phyllobacteriaceae, Rhizobiales, Burkholderiaceae, Burkholderiaceae. Inflammatory status in PTB patients may be associated with the increased abundance of Clostridia and decreased abundance of Prevotella. We found that the abundance of Solobacterium and Actinobacteria was higher in the patients. There were 4 significant differences (p < 0.05) in the two groups which belonged to four metabolic categories, including endocytosis, phosphotransferase system (PTS), toluene degradation, and amoebiasis.ConclusionWe applied the approach of metagenomic sequencing to characterize the features of gut microbiota in PTB patients. The present study provided a detailed analysis of the characterization of the gut microbiota in patients based on the clinic. According to the metagenome analysis, our results indicated that the gut microbiota in PTB patients was significantly different from healthy control samples as characterized by the bacteria and metabolic pathway. The richness of the gut microbiota in patients was revealed. It was hypothesized that the above-mentioned changes of the gut microbiota could exert an impact on the development of PTB through the downstream regulation of the immune status of the host by way of the gut–lung axis.  相似文献   

10.
Concentrations of zinc, copper, lead and cadmium in seawater and in some benthic algae from Sørfjorden are reported. The concentration factors for Fucus vesiculosus and Ascophyllum nodosum are in good agreement with values given by other authors, even though the zinc concentrations are about ten times larger than those found in most previous work. The concentration factors obtained for zinc and cadmium are essentially the same in the whole area; however, for copper and lead the values decrease towards the mouth of the fjord.  相似文献   

11.
The Western capercaillie (Tetrao urogallus) is a keystone species of Palearctic boreal and altitude coniferous forests. With the increase of mountain leisure activities and habitat loss, populations are declining in most mountain ranges in Western Europe. Recent work has shown that the populations from the Pyrenees and Cantabrian Mountains survived a severe bottleneck during the 19th century, and are still considered as threatened due to habitat fragmentation and isolation with other populations. We present an extensive phylogeographic study based on mitochondrial DNA sequence (control region) extracted non-invasively from faeces collected throughout the species range (from western European mountains to central and eastern Europe, Fenno-Scandia, Russia and Siberia). We also compared our results with DNA sequences of closely related black-billed capercaillie (T. parvirostris). We found that populations from Pyrenees and Cantabrians are closely related but are different from all other capercaillie populations that form a homogenous clade. Therefore, we consider that these South-Western populations should be considered as forming an Evolutionary Significant Unit that needs an appropriate management at a local scale. We also discuss the possible locations of glacial refugia and subsequent colonisation routes in Eurasia, with a Western “aquitanus” lineage from Iberia and Balkans, and an Eastern “urogallus” lineage from Southern Asia. This work might have important implication for capercaillie conservation strategies to define important areas for conservation, and to prevent possible exchange or introductions of individuals originated from other lineages. Electronic Supplementary Material The online version of this article (doi: ) contains supplementary material, which is available to authorized users.  相似文献   

12.
Vanilla borneensis Rolfe is considered as a rare, endemic and threatened terrestrial climbing orchid of Assam, India. The plant is restricted to only two pockets of Assam with a poor population size. Therefore, conservation of this plant through proper scientific investigation is urgently needed. The present study has as its objectives to study the distribution, standardization of suitable macropropagation methods for reinforcement and reintroduction in suitable wild habitat, as determined by ecological niche modelling (ENM) for the purposes of conservation. For improving the conservation status of the species, potential area and habitat for reintroduction was determined using maximum entropy (MaxEnt) distribution modelling algorithm. Seed germination under natural conditions was found to be very poor for which a macropropagation protocol was standardized; plantlets were raised and reinforced to locations where the population size is very small i.e., mean density, frequency of occurrence and abundance in relation to other associated species was 17.77, 14.16 and 0.82 respectively. Macropropagation method standardized here through cutting was found to be more efficient in terms of time and cost. Application of 100 ppm indole −3- butyric acid (IBA) and 40 ppm naphthalene acetic acid (NAA) significantly improved rooting traits. Further, survival rate was measured significantly very high at 73% while 1000 numbers of V. borneensis plantlets were transferred to the field. Present study has improved the population and conservation status of V. borneensis.  相似文献   

13.
《Reproductive biology》2020,20(4):541-546
Obesity is becoming pandemic and is associated with impaired reproductive potential. Oxidative stress, low-grade chronic inflammation and mitochondrial dysfunctions, which characterize obesity, strongly affect oocyte environment and function.Supplementation with antioxidant and anti-inflammatory compounds has been suggested to improve fertility. Here we evaluated the effect of α-lipoic acid and myo-inositol supplementation on the oocyte environment of infertile obese women.Nineteen normal-weight and twenty-three obese women, infertile for non-ovarian reasons, were recruited. For two months before ovarian stimulation, all women received 400 μg/die folic acid, whereas 15 obese were additionally supplemented with 800 mg α-lipoic acid, 2 g myo-inositol/die.Antioxidant capacity was measured in follicular fluid by enzymatic assay; mitochondrial DNA (mtDNA) content and mRNA levels of two respiratory chain subunits were analyzed in granulosa cells by Real-time PCR.Pregnancy rate was similar between normal-weight and treated obese, and lower in untreated obese patients. Supplemented women showed significantly higher antioxidant levels in follicular fluid compared to the two groups taking only folic acid. Conversely, granulosa cells mtDNA content was decreased in treated and higher in untreated obese patients compared to normal-weight women, suggesting mtDNA increases to compensate for oxidative-stress damages. Reduced expression of respiratory subunits in untreated obese may confirm mitochondria impairment. Interestingly, mtDNA levels inversely correlated to both total and metaphase II oocyte number.In this preliminary study, combined supplementation of α-lipoic acid and myo-inositol in infertile obese women was associated with amelioration in the oxidative status of the oocyte environment, possibly contributing to a higher pregnancy rate.  相似文献   

14.
It is fairly well known that Darwin was inspired to formulate his theory of natural selection by reading Thomas Malthus’s Essay on the Principle of Population. In fact, by reading Darwin’s notebooks, we can even locate one particular sentence which started Darwin thinking about population and selection. What has not been done before is to explain exactly where this sentence – essentially Malthus’s ideas about geometric population growth – came from. In this essay we show that eighteenth century mathematician Leonhard Euler is responsible for this sentence, and in fact forms the beginning of the logical chain which leads to the creation of the theory of natural selection. We shall examine the fascinating path taken by a mathematical calculation, the many different lenses through which it was viewed, and the path through which it eventually influenced Darwin.  相似文献   

15.
Human activity has promoted the invasion of the Galápagos Islands by alien species from each of the five classes of vertebrates. We review the current distribution of alien vertebrates in the archipelago, their impacts on native species, and management efforts aimed at alien vertebrates. A total of 44 species have been reported in the archipelago, with 20 species establishing feral populations. Mammals were the first group arriving in the archipelago and remain the most numerous, with 10 established species. Alien birds invaded after mammals and four species have established populations. Reptiles, amphibians, and fish invaded later and are represented by three, one, and two species, respectively. Alien mammals are the most injurious to native biota, contributing to the decline or extinction of several species. Aside from mammals, no other class of alien vertebrate has had documented impacts on native species. Several populations of large and medium-sized mammals and birds have been eradicated.  相似文献   

16.
Using IUCN Red List species as biodiversity surrogates, supplemented with additional analyses based on ecoregional diversity, priority areas for conservation in Mesoamerica, Chocó, and the Tropical Andes were identified using the methods of systematic conservation planning. Species’ ecological niches were modeled from occurrence records using a maximum entropy algorithm. Niche models for 78 species were refined to produce geographical distributions. Areas were prioritized for conservation attention using a complementarity-based algorithm implemented in the ResNet software package. Targets of representation for Red List species were explored from 10 to 90% of the modeled distributions at 10% increments; for the 53 ecoregions, the target was 10% for each ecoregion. Selected areas were widely dispersed across the region, reflecting the widespread distribution of Red List species in Mesoamerica, Chocó, and the Tropical Andes, which underscores the region’s importance for biodiversity. In general, existing protected areas were no more representative of biodiversity than areas outside them. Among the countries in the region, the protected areas of Belize performed best and those of Colombia and Ecuador worst. A high representation target led to the selection of a very large proportion of each country except Colombia and Ecuador (for a 90% target, 83–95% of each country was selected). Since such large proportions of land cannot realistically be set aside as parks or reserves, biodiversity conservation in Mesoamerica, Chocó, and the Tropical Andes will require integrative landscape management which combines human use of the land with securing the persistence of biota. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

17.
Based on an updated census for the endangered Dupont’s lark (Chersophilus duponti), we conducted a phytosociological survey of 167 sites representative of the distribution area of the species in Europe. Results were used as a starting point for conservation assessment. According to our observations, the bird selects flat deforested areas colonized by small shrubs corresponding to successional, subclimax stages that are either naturally or artificially exploited. Four groups of scrubs were occupied by the bird: (1) supramediterranean dwarf cushion scrubs dominated by Genista pumila ssp. rigidissima or Erinacea anthyllis; (2) gypicolous shrublands and grasslands associated with Lygeum spartum; (3) shrubs dominated by chamaephytes producing allelopathic substances (Thymus, Lavandula, Salvia) and showing different facies according to the level of disturbance; and (4) supramediterranean acidophilous scrubs dominated by Cistus, Erica or Cytisus species. As management measures, we propose reducing tree density in flat areas, promoting the growth of chamaephytes by clearing phanerophytes, and encouraging traditional low-level transhumance grazing. These measures will provide high-quality habitats and help preserve, or even expand, habitable patches to ensure the viability of the European metapopulation of this rare and sensitive songbird.  相似文献   

18.
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   

19.
Large terrestrial carnivores especially have experienced substantial declines in range and numbers. Changes in land use are a main driver of such declines, yet various developing countries have accelerated land use change through state-led land reform programmes. One of the most renowned land reform programmes is Zimbabwe’s fast track land reform programme (FTLRP), which resulted in fast and compulsory subdivision of large commercial farms into indigenized small scale commercial and subsistence farms. Several case studies have shown an impact of the FTLRP on wildlife, however, its effect on wildlife populations at a nationwide scale remains largely unknown. Due to its wide-ranging nature, the cheetah (Acinonyx jubatus) is particularly vulnerable to changes in land use. In this study I used questionnaire survey and citizen science data to determine the population status and distribution of the cheetah 15 years after introduction of the FTLRP. I also assessed the level of human-cheetah conflict, and attitudes of commercial and subsistence farmers towards cheetah. I found dramatic range contractions and population declines, particularly in the landscape outside protected areas. Despite minimal conflict, subsistence farmers were less tolerant to cheetah than commercial farmers. Consequently, land reform is likely to have increased the hostility of the cheetah landscape outside protected areas. This study is one of the most comprehensive species assessments to date. It provides valuable empirical data on the implications of land use change and emphasizes how a lack of knowledge impedes our ability to recognize a species vulnerability to (local) extinction risk.  相似文献   

20.
This article examines the combined influence of cognitions (i.e., impact beliefs) and affect (i.e., feelings) on normative beliefs (i.e., support for management options) about wolves and brown bears. Data were obtained from stratified random face-to-face interviews (n = 1,611). The survey was conducted in the Abruzzo Lazio and Molise National Park (central Italy), where people have a long history of coexistence with large carnivores. Knowledge was hypothesized to moderate the relationships of beliefs and feelings on support for management actions. Path analyses supported the role of affect in mediating perceived impact beliefs and support for the protection of large carnivores. Knowledge moderated these relationships in the case of wolves but not brown bears. Residents of the national park had more knowledge about bears than wolves, which might partly explain both the stronger effect that knowledge had on the affective component and its lack of a moderating effect on the bear model. Overall, our findings show the positive attitude of residents toward large carnivores and support the idea of affect being more important than cognition in predicting normative beliefs.  相似文献   

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