首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
A general, logistic population model is used to explore the dynamics of harvested elephant populations. The model includes two features peculiar to elephant populations and the harvesting of ivory. First, because of the shape of the growth curve of tusks with age, the conversion factor that relates the number of elephants killed to the ivory yield in weight is not constant, but a function of the population size. Second, tusks from animals that die from natural causes can be retrieved and included in the total yield of ivory. The implications of the relationship between tusk size and age of an animal on the maximum sustainable yield in terms of ivory tonnage and in terms of the number of tusks are explored. The nonequilibrium implications of the tusk growth curve on the population dynamics under different harvesting strategies are also investigated. Results indicate that the maximum sustainable yield is achieved at very low harvest rates with population levels close to the pristine equilibrium. When tusks from animals that die of natural causes are included in the harvest, the maximum yield may, depending on the mortality and recruitment parameters, occur when there is no direct harvest.  相似文献   

2.
Levels and trends of illegal killing of elephants are measured by the Convention on International Trade in Endangered Species (CITES) Monitoring the Illegal Killing of Elephants (MIKE) programme in sites across Africa and Asia. In the mostly unprotected Laikipia–Samburu MIKE site in northern Kenya, elephant mortality data were collected using both standard law enforcement monitoring procedures, relying on patrolling, and participatory methods involving local communities. Qualitatively, traditional patrolling techniques were more successful in protected areas whereas participatory approaches provided more information outside protected areas, where elephant were most at risk from ivory poachers. A minimum of 35% of the 389 verified carcasses during 2001–2003 were illegally killed. In this baseline study, land uses ranked from highest to lowest by the proportion of illegally killed elephants (PIKE) were community conservation areas, government trust lands, forest reserves, private ranches, settlement areas and national reserves. PIKE trends derived from traditional and participatory data sources were similar across years and indicate elephants were at greater risk in regions outside government or privately patrolled areas. We suggest that PIKE is a useful index for comparing levels and trends in illegal killing of elephants, and that carcass ratios and presence/absence of tusks are useful proxy indicators of mortality and its causes.  相似文献   

3.
Harvesting of wild populations can cause the evolution of morphological, behavioral, and life history traits that may compromise natural or sexual selection. Despite the vulnerability of large mammals to rapid population decline from harvesting, the evolutionary effects of harvesting on mega‐fauna have received limited attention. In elephants, illegal ivory harvesting disproportionately affects older age classes and males because they carry large tusks, but its' effects on tusk size for age or tusk size for stature are less understood. We tested whether severe historical elephant harvests eliminated large tuskers among survivors and whether elephants born thereafter had smaller tusks. Adjusting for the influence of shoulder height – a metric strongly correlated with body size and age and often used as a proxy for age – we compared tusk size for elephants sampled in 1966–1968, prior to severe ivory harvesting in the late 1970s and early 1980s, with tusk size of survivors and elephants born during population recovery in the mid‐1990s. In a regional population, tusk length declined by ˜21% in male and by ˜27% in female elephants born during population recovery, while tusk length declined by 22% in males and 37% in females among survivors. Tusk circumference at lip declined by 5% in males but not in females born during population recovery, whereas tusk circumference reduced by 8% in male and by 11% in female survivors. In a single subpopulation, mean tusk length at mean basal tusk circumference declined by 12.4% in males and 21% in females. Tusk size varied between elephant social groups. Tusk homogeneity within social groups and the often high genetic similarity within social groups suggest that tusk size may be heritable. Our findings support a hypothesis of selection of large tuskers by poachers as a driver of the decline in tusk size for age proxy and contemporary tusk evolution in African elephants.  相似文献   

4.
An important area of biology involves investigating the origins in animals of traits that are thought of as uniquely human. One way that humans appear unique is in the importance they attach to the dead bodies of other humans, particularly those of their close kin, and the rituals that they have developed for burying them. In contrast, most animals appear to show only limited interest in the carcasses or associated remains of dead individuals of their own species. African elephants (Loxodonta africana) are unusual in that they not only give dramatic reactions to the dead bodies of other elephants, but are also reported to systematically investigate elephant bones and tusks that they encounter, and it has sometimes been suggested that they visit the bones of relatives. Here, we use systematic presentations of object arrays to demonstrate that African elephants show higher levels of interest in elephant skulls and ivory than in natural objects or the skulls of other large terrestrial mammals. However, they do not appear to specifically select the skulls of their own relatives for investigation so that visits to dead relatives probably result from a more general attraction to elephant remains.  相似文献   

5.
AGE CRITERIA FOR THE AFRICAN ELEPHANT   总被引:1,自引:0,他引:1  
1. The paper is based on a collection of 385 lower jaws of the African elephant (Loxodonta a. africana Blumenbach) from western Uganda. 2. Thirty age groups are described and illustrated, which are related to the progress of eruption and wear of the six teeth in each side of the lower jaw. 3. Correct identification of individual teeth in the series is essential and several checks are described. Thus, when length is plotted against width for the six teeth the points fall into six well - defined groups. Frequency distributions of laminary indices and lamella numbers support the belief that teeth have been correctly identified, but overlapping, distributions preclude identification on these characters alone. 4. The presence of abnormal seventh molars in four jaws is described. 5. Chronological ages have been assigned to the relative age groups. Information on age and growth of captive animals has been considered and the general form of the growth curve established. Arbitrary estimates of the intervals between successive age groups were made and subsequently checked against growth and seasonal ridges on the roots. These indicate an upper age limit of about 60 years, which is compatible with fuller information on Indian elephants. 6. Growth curves support the validity of the ages assigned. Asymptotic heights at shoulder (∞) are respectively 317 cm and 298 cm for males from Murchison Falls and Queen Elizabeth National Parks. For females no distinction is made (because the sample from the latter area is small) and ∞ is 272 cm. 7. Growth in weight has also been established but shows no significant differences between the two populations. The mean maximum weight of females is 2766 kg (6100 lb), and of males 5450 kg (12000 lb). Growth apparently continues throughout life. 8. Tusk growth is analysed. There is a linear increase in weight of female tusks from eruption at 1–3 years up to the oldest group, with an indicated mean combined weight of 17.7 kg (39 lb) at 60 years. Male tusks show an increasing rate of growth throughout life to a mean combined weight of about 109 kg (240 lb) at 60 years. Big tusks are generally the result of prolonged growth; extremely big tusks probably result from prolonged and above average rate of growth. 9. Seasonal and annual incremental layers on the root 3 of the teeth are briefly described; these give an objective estimate of the chronological intervals between the relative age groups. 10. Field age criteria are presented which are derived from these growth curves. 11. The age at puberty in the female elephant is discussed and compared with earlier conclusions. There is evidence of a retardation in recent years in the Murchison Falls National Park (South bank) population and of a lengthening of the mean calving interval. This considerable depression of the reproductive rate, which is almost certainly density dependent, agrees with the observed lower recruitment in this population. 12. Survivorship curves constructed from material representing 325 natural deaths are presented for the two populations. If estimates of the age at puberty and the reproductive rate are taken into account, the expected differences in recruitment are found. 13. The calculated mean expectation of life is less than 15 years. 14. Mean individual weight is estimated at about 3800 lb.  相似文献   

6.
Evaluation of alternative techniques used to estimate elephant population sizes is important in order to assess the accuracy of the results obtained, upon which management decisions may be based. Data from annual helicopter surveys carried out in the Addo Elephant National Park (1978–97) are compared with registration counts obtained from intensive ground surveys in which all elephants within the park are individually known. On average, total population size estimated in aerial surveys is 8.0% lower than registration counts (n1997 = 251), aerial calf (< 1 year) counts are 48.8% lower than registration counts, and aerial carcass counts are 50% below the total number of deaths documented in ground surveys. Registration counts provide more accurate demographic data than aerial surveys, the results of which are shown to vary widely and unpredictably, thus compromising their value. Where population estimates rely exclusively on aerial surveys, replicate counts are recommended in order to generate confidence intervals.  相似文献   

7.
《Anthrozo?s》2013,26(4):232-244
ABSTRACT

This article examines the presence of elephants in civilizations of the ancient Nile valley, where they were hunted and distributed to Egypt and to the Classical Greco-Roman world for ivory, amusement, and military purposes. The full study of elephants requires diverse multidisciplinary research on their evolution, taxonomy, extinction, climate change, the history of human—elephant interactions, and modern issues relating to elephant and ivory policy. This regional view of the past illuminates some of the deep roots of these modern issues in human—elephant relations.  相似文献   

8.
Drought mortality of bush elephants in Hwange National Park, Zimbabwe   总被引:2,自引:1,他引:1  
African bush elephants inhabiting the undeveloped Kalahari Sands region of Hwange National Park, Zimbabwe are subject to episodic mortality during droughts. We monitored the drought‐related mortality of elephants in Hwange National Park over the course of an extended drought between 1993 and 1995. The drought‐related mortality of elephants was higher during 1994 than 1995, despite significantly higher rainfall in 1994 than 1995. We found significant differences in the age‐specific mortality of elephants during 1994 and 1995. The cumulative mortality profile from this study differed significantly from previous die‐offs at this site, with a higher mortality among adult age classes than that reported from earlier studies in Hwange National Park. The effective duration of the rainy season, not total annual precipitation, appears to be the best predictor for the potential severity of drought mortality among elephants in the Kalahari Sands habitats of Hwange National Park.  相似文献   

9.
  • 1 This report presents the results of a survey into the current status of the Nile crocodile in the major waters of central and western Uganda, made on behalf of the Uganda Fisheries Department and the Trustees of the Uganda National Parks.
  • 2 The waters covered by the survey are described briefy
  • 3 Crocodile numbers and distribution were assessed by diurnal aerial counting and nocturnal ground counts as described by Graham (1968). The major sources of error inherent in these techniques are recognised and discussed. Efforts to reduce bias in results included the use of a light helicopter to obtain data for comparison with those obtained from a conventional aircraft. Comparative costs are also presented.
  • 4 Inaccessible areas of dense papyrus were searched at night from a helicopter equipped with a spotlight.
  • 5 Information was obtained from fishermen in Lake Albert on the status of crocodile to corroborate other results.
  • 6 The analysed results of aerial and ground counts give estimates of less than 100 crocodile outside the Murchison Falls National Park, indicating the species' reduction to the status of an ‘occasional’ or ‘rare’ animal. Within the National Park crocodile occur in two populations separated by the Murchison Falls. Below the Falls it is estimated that there are 1064 crocodile, and above 433.
  • 7 By use of aerial photography 369 crocodile from the larger of the National Park's populations were measured for length. From Graham's (1968) age/length data, age classes are ascribed to those measured. This, together with data from the counts, permitted the computation of a survivorship curve for the population. This is presented with two possible alternatives. From these curves it does not appear that the population is declining through lack of recruitment.
  • 8 From the aerial photographs river banks are classified into four crude categories. By relating crocodile in the photographs to the nearest bank category, it is shown that they have a marked preference for sandy banks over swampy shores, hard flat earth or cliffs. It is also shown that smaller crocodile make more use of swampy areas than larger specimens.
  • 9 Biomass densities for both crocodile populations in the National Park are computed. The larger shows a biomass of 347 kg/km of shoreline which compares with 350.2 kg/km for Lake Rudolf (Graham's (1968) data modified), the smaller 75.3 kg/km.
  • 10 The decline of crocodile in Uganda is attributed to expanding human populations and over-exploitation for skins.
  • 11 Recommendations for the future conservation and management of crocodile are presented. These are based on reducing immature mortality rates by hatching eggs and artificially rearing small crocodiles for a period of 6 months after hatching. Some of these should be used to augment recruitment in the National Park populations, and the surplus placed in other waters until of an exploitable size.
  相似文献   

10.
African elephants (Loxodonta africana) play a vital role in most African ecosystems, with their opportunity to alter the entire ecosystem by their sheer numbers. Defining and measuring animal welfare has been much discussed. One potential way of determining an animal's welfare is to record the absence or presence of stress. Little research on elephant welfare has so far been performed in the Serengeti ecosystem. The aim of this study was to record the faecal glucocorticoid metabolite levels of African elephants in areas with high or with minimum human interference. A total of 117 faecal samples were collected from randomly located single elephants as well as family herds in the northern, central and western Serengeti National Park (SNP) as well as in Grumeti Game Reserve and Ikoma Open Area, northern Tanzania in 2010. Elephants had higher levels of faecal glucocorticoid metabolites in the areas outside, compared with areas inside SNP. No single males were observed outside SNP, and in general, higher abundance of elephants was observed inside SNP. This suggests that elephants may prefer to reside in the potential safer areas inside the national park, demonstrating the importance of protected areas to improve the welfare of elephants.  相似文献   

11.
Reliable evidence of trends in the illegal ivory trade is important for informing decision making for elephants but it is difficult to obtain due to the covert nature of the trade. The Elephant Trade Information System, a global database of reported seizures of illegal ivory, holds the only extensive information on illicit trade available. However inherent biases in seizure data make it difficult to infer trends; countries differ in their ability to make and report seizures and these differences cannot be directly measured. We developed a new modelling framework to provide quantitative evidence on trends in the illegal ivory trade from seizures data. The framework used Bayesian hierarchical latent variable models to reduce bias in seizures data by identifying proxy variables that describe the variability in seizure and reporting rates between countries and over time. Models produced bias-adjusted smoothed estimates of relative trends in illegal ivory activity for raw and worked ivory in three weight classes. Activity is represented by two indicators describing the number of illegal ivory transactions – Transactions Index – and the total weight of illegal ivory transactions – Weights Index – at global, regional or national levels. Globally, activity was found to be rapidly increasing and at its highest level for 16 years, more than doubling from 2007 to 2011 and tripling from 1998 to 2011. Over 70% of the Transactions Index is from shipments of worked ivory weighing less than 10 kg and the rapid increase since 2007 is mainly due to increased consumption in China. Over 70% of the Weights Index is from shipments of raw ivory weighing at least 100 kg mainly moving from Central and East Africa to Southeast and East Asia. The results tie together recent findings on trends in poaching rates, declining populations and consumption and provide detailed evidence to inform international decision making on elephants.  相似文献   

12.
We use genetic measures of relatedness and observations of female bonding to examine the demographic signature of historically heavy poaching of a population of free-ranging African elephants. We collected dung samples to obtain DNA and observed behaviour from 102 elephant families over a 25-month period in 2003–2005 in Mikumi National Park, Tanzania. Poaching reduced the population by 75% in the decade prior to the 1989 ivory trade ban; park records indicate that poaching dropped significantly in Mikumi following the ban. Using 10 microsatellite loci, DNA was genotyped in 203 elephants and pair-wise relatedness was calculated among adult females within and between groups. The Mikumi population is characterized by small group size, considerable variation in group relatedness, females with no first-order adult relatives and females that form only weak social bonds. We used gene-drop analysis and a model of a genetically intact pedigree to compare our observed Mikumi group relatedness to a simulated genetically intact unpoached expectation. The majority of groups in Mikumi contain 2 to 3 adults; of these, 45% were classified as genetically disrupted. Bonding, quantified with a pair-wise association index, was significantly correlated with relatedness; however only half of the females formed strong bonds with other females, and relatedness was substantially lower for a given bond strength as compared to an unpoached population. Female African elephants without kin demonstrated considerable behavioural plasticity in this disturbed environment, grouping with other females lacking kin, with established groups, or remaining alone, unable to form any stable adult female-bonds. We interpret these findings as the remaining effect of poaching disturbance in Mikumi, despite a drop in the level of poaching since the commercial trade in ivory was banned 15 years ago.  相似文献   

13.
In Africa, most protected forests are in densely human-dominated landscapes where human–wildlife conflict is intense. We documented farmer perceptions and responses to crop-raiding wildlife from Kibale National Park, Uganda. Crop raiding was mostly (95%) by baboons (Papio anubis) and elephants (Loxodonta africana). While the financial loss caused by baboons and elephants did not differ, elephants were perceived as more damaging. Guarding and trenches were perceived as the most effective deterrent strategies for baboons and elephants, respectively. Distance from the park boundary and household income were significantly associated with a greater likelihood of crop raiding. Distance from the park, household head age and the species that raided crops, influenced whether a household applied one or more deterrent strategies. Households headed by women or older adults were most vulnerable, experiencing greater losses to raiding. Patterns of human–wildlife conflict around Kibale forest are complex, but the extent of crop damage was mostly determined by distance from the park and farm socio-economic status and thus their ability to mitigate or deter raiding. Managing crop raiding requires collaboration between the park and affected farmers to ensure that mutually managed deterrent methods, such as trenching (elephants) and guarding (baboons), are effectively shared, applied and maintained.  相似文献   

14.
Twenty-two years of rainfall data from six sites, 5 years of animal migration data and 2 years of water quality at 13 sites were explored to quantify the role of water in the Tarangire ecosystem. Inter-annual fluctuations in rainfall were large and not predictable solely from the Southern Oscillation Index. Seasonal fluctuations of rainfall were pronounced, with marked wet and dry seasons. In the dry season, the only drinking water available for wildlife was the Tarangire River and a number of small, scattered wetland-fringed water holes. Their salinity was often high (>8 ppt) and was higher in dry years than in wet years, as well as at the start of the wet season. Water quantity and quality may control the annual migration of wildebeest, zebra, elephants and buffaloes. These animals aggregate in the dry season in areas with the least salty water. The timing of seasonal variations in rainfall is largely predictable and controls annual migration. All wildebeest and most zebras migrated out of Tarangire National Park and into the wider Tarangire ecosystem at the start of the wet season, and they returned into the park in the dry season. Some elephants and buffaloes also migrated in out of the park and a larger resident population remained, whose size may vary inter-annually depending on surface water quantity and quality. The extent of the migration zone may also vary inter-annually.This revised version wa published online in March 2005 with corrections to the issue cover date.  相似文献   

15.
A 10-year study revealed that after severe poaching (>93% killed) of elephants ( Loxodonta africana ) in Zambia's North Luangwa National Park (NLNP) during the 1970s and 1980s, the age of reproduction in females was greatly reduced. Fifty-eight per cent of births were delivered by females aged 8.5–14 years, an age at which elephants were reported to be sexually immature in nearby South Luangwa National Park (SLNP) before poaching. The mean age of females at first birth (AFB) (1993, 1994) was 11.3 years. Prior to poaching, the mean age AFB in SLNP was 16 years. The NLNP age structure and sex ratio were skewed, mean family unit size was reduced, and 37% of family units contained no females older than 15 years. Twenty-eight per cent of family units were comprised entirely of a single mother and her calf, and 8% of units consisted only of orphans who would have been considered sexually immature prior to poaching. Only 6% of survivors were older than 20 years, the age at which females in little-poached populations generally become most reproductively active. After a community-based conservation programme and the UN-CITES ban on the ivory trade were introduced, no elephants were recorded killed. In spite of a high reproductive rate, 6 years after poaching decreased, the density of the NLNP population had not increased, supporting predictions that the removal of older matriarchs from family units will have serious consequences on the recovery of this species.  相似文献   

16.
Human conflict generally has substantial negative impacts on wildlife and conservation. The recent civil war (1995-2006) in the Democratic Republic of Congo (DRC) resulted in a significant loss of wildlife, including elephants, due to institutional collapse, lawlessness and unbridled exploitation of natural resources such as minerals, wood, ivory and bushmeat. We used data from distance sampling surveys conducted before and after the war in a protected forest, the Okapi Faunal Reserve, to document changes in elephant abundance and distribution. We employed Generalized Additive Models to relate changes in elephant distribution to human and environmental factors. Populations declined by nearly fifty percent coinciding with a major increase in elephant poaching as indicated by reports of ivory trade during the war. Our results suggest that humans influenced elephant distribution far more than habitat, both before and after the war, but post-war models explained more of the variation. Elephant abundance declined more, closer to the park boundary and to areas of intense human activity. After the war, elephant densities were relatively higher in the centre of the park where they were better protected, suggesting that this area may have acted as a refuge. In other sites in Eastern DRC, where no protection was provided, elephants were even more decimated. Post-war dynamics, such as weakened institutions, human movements and availability of weapons, continue to affect elephants. Survival of remaining populations and recovery will be determined by these persistent factors and by new threats associated with growing human populations and exploitation of natural resources. Prioritizing wildlife protection, curbing illegal trade in ivory and bushmeat, and strengthening national institutions and organizations in charge of conservation will be crucial to counter these threats.  相似文献   

17.
This 1981 survey assesses elephant-induced bark damage and mortality in the population of baobab trees at Lake Manyara National Park. Comparisons are made with a similar survey conducted there in 1969. The age structure of the baobab population is estimated and linear and exponential survivorship curves are calculated. Damage and mortality increased over the 11 year interval but the basic form of the population age structure remained unchanged. Damage was found to increase while mortality decreased with tree size. Both damage and mortality are lower in the southern part of the park where the trees are less accessible to elephants. The recorded mortality was higher than expected values taken from the calculated survivorship curves but lower than mortalities in other parks where baobabs and elephants have been found together at high densities.  相似文献   

18.
AGE CRITERIA AND VITAL STATISTICS OF A BLACK RHINOCEROS POPULATION   总被引:2,自引:0,他引:2  
Tsavo National Park, in Kenya, probably contains the largest population of black rhinoceros (Diceros bicornis (L.)) left in existence. Large-scale damage of the vegetation initiated by elephants and aggravated by fire has changed considerable areas of the park. The ecology of the black rhinoceros in this changing environment has been studied; the present status and population structure is considered here, including the development of detailed ageing criteria for the species, an analysis of natural mortality and survivorship, and a record of the structure of the living populations within the major habitat types. Crania and mandibles were collected from 506 rhinoceros found dead in all areas of the park. This material was divided into 20 relative age classes based on dental characteristics. Crude chronological ages, based on an estimate of the maximum expectation of life and the examination of seven known-age dental records of captive animals, were assigned to each age class. These crude ages were then refined by examination of 16 dental records of known-age wild rhinoceros, and a chronological age scale established. A survivorship curve of the population was thus constructed. Annual mortality during the first and second year of life is about 16%, and the indicated mean annual mortality from 5–25 y is 9.8%. A theoretical model of the population structure is shown, and analysis of the annual mortality and recruitment at birth suggests that the population was stable during the 1960's. Assuming the data represent a stable population the mean expectation of life at birth is 8.4 y. Thirteen major habitat types are described. The characteristics of the rhinoceros population within each habitat type were established both from ground studies and aerial observations. Nearly 700 rhinoceros were identified and catalogued on the ground, in sample areas selected for intensive study. Population structures, cow: calf ratios, and recruitment appear to be average in most habitat types. The analysis of recruitment at birth and mortality during the first year of life, both from computations from the survivorship curve and from the structure of the living populations, support the validity of the ageing criteria, and further suggest that the population was stable during the 1960's. Finally, the relationship between the elephant and the rhinoceros in the changing environment is discussed with reference to recent findings in elephant ecology. In conclusion it is recommended that population reduction of the Tsavo elephants should be initiated.  相似文献   

19.
Understanding the population dynamics of savanna elephants depends on estimating population parameters such as the age at first reproduction, calving interval and age-specific survival rates. The generation of these parameters, however, relies on the ability to accurately determine the age of individuals, but a reliable age estimation technique for free-ranging elephants is presently not available. Shoulder heights of elephants were measured in 10 populations in five countries across southern and eastern Africa. Data included shoulder height measurements from two populations where the age of each individual was known (i.e. Addo Elephant National Park, South Africa and Amboseli National Park, Kenya). From the known-age data, Von Bertalanffy growth functions were constructed for both male and female elephants. Savanna elephants were found to attain similar asymptotic shoulder heights in the 10 populations, while individuals in the two known-age populations grew at the same rate. The Von Bertalanffy growth curves allowed for the accurate age estimation of females up to 15 years of age and males up to 36 years of age. The results indicate that shoulder height can serve as an indicator of chronological age for elephants below 15 years of age for females and 36 years of age for males. Ages derived from these growth curves can then be used to generate age-specific population variables, which will help assess the demographic status of savanna elephant populations across Africa.  相似文献   

20.
Efforts to curb elephant poaching have focused on reducing demand, confiscating ivory and boosting security patrols in elephant range. Where land is under multiple uses and ownership, determining the local poaching dynamics is important for identifying successful conservation models. Using 2,403 verified elephant, Loxodonta africana, mortality records collected from 2002 to 2012 and the results of aerial total counts of elephants conducted in 2002, 2008 and 2012 for the Laikipia-Samburu ecosystem of northern Kenya, we sought to determine the influence of land ownership and use on diurnal elephant distribution and on poaching levels. We show that the annual proportions of illegally killed (i.e., poached) elephants increased over the 11 years of the study, peaking at 70% of all recorded deaths in 2012. The type of land use was more strongly related to levels of poaching than was the type of ownership. Private ranches, comprising only 13% of land area, hosted almost half of the elephant population and had significantly lower levels of poaching than other land use types except for the officially designated national reserves (covering only 1.6% of elephant range in the ecosystem). Communal grazing lands hosted significantly fewer elephants than expected, but community areas set aside for wildlife demonstrated significantly higher numbers of elephants and lower illegal killing levels relative to non-designated community lands. While private lands had lower illegal killing levels than community conservancies, the success of the latter relative to other community-held lands shows the importance of this model of land use for conservation. This work highlights the relationship between illegal killing and various land ownership and use models, which can help focus anti-poaching activities.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号