Intensive Hunting Research Articles

Can faecal glucocorticoid metabolites be used to monitor body condition in wild Upland geese Chloephaga picta leucoptera?

The measurement of faecal glucocorticoid metabolites is used as a non-invasive technique to study stress in animal populations. They have been used most widely in mammals, and mammalian studies have also treated issues such as sample stability and storage methods. In birds, faecal corticosterone metabolite (CM) assays have been validated for a small number of species, and adequate storage under field conditions has not been addressed explicitly in previous studies. Furthermore, while it is well-established that baseline plasma corticosterone levels in birds rise with declining body condition, no study so far investigated if this relationship is also reflected in faecal samples. We here present data of a field study in wild Upland geese Chloephaga picta leucoptera on the Falkland Islands, testing different storage methods and investigating the relationship of faecal CM concentrations to body condition and reproductive parameters. We found that faecal CM measures are significantly repeatable within individuals, higher in individuals with lower body condition in both male and female wild Upland geese and higher in later breeding females with smaller broods. These results suggest that measuring faecal CM values may be a valuable non-invasive tool to monitor the relative condition or health of individuals and populations, especially in areas where there still is intense hunting practice.

오리피스 유량계의 유동헌팅 원인과 배관경과의 상관관계에 대한 배관망해석 연구

일반적으로 유동헌팅현상은 대부분의 오리피스 유량계에서 관찰되나 유동헌팅의 크기는 각 계량 시스템에 따라 다르다. 이에, 실제 배관계통에서 배관경과 유동의 불안정성, 유동헌팅율간의 영향을 조사하고자 유량계 관경과 유량계 전후단 배관의 직경을 변경하면서 이에 따른 유동의 특성 변화와 헌팅율과의 관계에 대하여 1차원 배관망해석 모델을 구축하고 해석을 수행하였다. 결과적으로, 유량계 배관경과 전후단 배관경의 변화에 따른 차압변화량과 유동헌팅율의 영향을 분석하고 그 상관관계를 규명하였다. Generally, the flow hunting is observed in almost all of the orifice meters but the intensity of the flow hunting is different at each metering system. In order to investigate the relations between pipe diameter and the flow instability or the flow hunting in a real metering system, a one-dimensional pipeline network model was built and analyzed for the examination of flow characteristics and relations to the flow hunting, changing diameters of the meter and the pipes before and after the meter. Finally, the effects of pressuredifference variation and flow hunting following to the variations of the diameters of the meter and the pipes before and after the meter were investigated and the relations were examined as well.

Differential impact of bushmeat hunting on monkey species and implications for primate conservation in Korup National Park, Cameroon

Bushmeat hunting is one of the primary threats to many large-bodied vertebrate species in African forests. However, species vary in their degree of vulnerability to hunting. We investigated the impact of hunting on monkey species in Cameroon’s Korup National Park (KNP) and examined how vulnerability to hunting varies among species. Data on primate abundance and hunting intensity were collected along 10 line transects, distributed across three survey areas in KNP. We assessed how the relative abundance of seven monkey species spatially varied between heavily and lightly hunted areas and evaluated temporal changes in the relative abundance and proportional representation of these species at a single hunted forest site and in bushmeat harvests. The putty-nosed and mona monkeys are most tolerant to heavy hunting pressure whereas the crowned monkey, drill, and red colobus are among the most vulnerable. At our heavily hunted survey site, the overall relative density of monkey groups increased through time but primate species richness declined. The proportional representation of Cercopithecus species, especially putty-nosed monkeys, increased through time, possibly due to competitive release. We also observed an increase in the proportional representation of the putty-nosed and mona monkeys and a reduced percent contribution of the red colobus and drill in hunter harvests. We conclude that hunting is driving some of Africa’s most threatened primate species (e.g., Preuss’s red colobus and the drill) to local extinction in KNP. We discuss intrinsic factors of species that might influence their degree of vulnerability and strategies to improve protection efforts in KNP.

Spatio‐temporal feeding selection of red deer in a mountainous landscape

AbstractUnderstanding the dietary consumption and selection of wild populations of generalist herbivores is hampered by the complex array of factors. Here, we determine the influence of habitat, season, and animal density, sex, and age on the diet consumption and selection of 426 red deer (Cervus elaphus scoticus) culled in Fiordland National Park, New Zealand. Our site differs from studies elsewhere both in habitat (evergreen angiosperm‐dominated forests) and the intensity of hunting pressures. We predicted that deer would not consume forage in proportion to its relative availability, and that dietary consumption would change among and within years in response to hunting pressures that would also limit opportunities for age and sex segregation. Using canonical correspondence analysis, we evaluated the relative importance of different drivers of variation in diet consumption assessed from gut content and related these to available forage in the environment. We found that altitude explained the largest proportion of variation in diet consumption, reflecting the ability of deer to alter their consumption and selection in relation to their foraging grounds. Grasses formed a high proportion of the diet consumption, even for deer culled several kilometres from the alpine grasslands. In the winter months, when the alpine grasslands were largely inaccessible, less grass was eaten and deer resorted to woody plants that were avoided in the summer months. Surprisingly, there were no significant dietary differences between adults and juveniles and only subtle differences between the sexes. Sex‐based differences in diet consumption are commonly observed in ungulate species and we suggest that they may have been reduced in our study area owing to decreased heterogeneity in available forage as the diversity of palatable species decreased under high deer browsing pressures, or by intense hunting pressure.

Focusing Conservation Efforts for the Critically Endangered Brown-headed Spider Monkey (Ateles fusciceps) Using Remote Sensing, Modeling, and Playback Survey Methods

Brown-headed spider monkeys (Ateles fusciceps), endemic to the Choco-Darien forests and lower Andean forests of NW Ecuador, are considered critically endangered. Unfortunately, scientific data regarding the actual status of populations is lacking. We combined satellite image analysis, species-specific habitat assessment, and a field survey technique using playback to focus conservation efforts for this species. First, we identified remaining forest via a LANDSAT mosaic and then applied species-specific criteria to delineate remaining forest with potential to hold populations. By combining this with the historical distribution from ecological niche modeling and predicted hunting intensity we generated a species-specific landscape map. Within our study area, forest capable of sustaining Ateles fusciceps covers 5872 km2, of which 2172 km2 (40%) is protected. Unprotected forest considered suitable for Ateles fusciceps extends to 3700 km2 but within this only 989 km2 (23%) is under low hunting pressure and likely to maintain healthy populations of Ateles fusciceps. To overcome problems of sampling at low primate density and in difficult mountain terrain we developed a field survey technique to determine presence and estimate abundance using acoustic sampling. For sites under low hunting pressure density of primates varied with altitude. Densities decreased from 7.49 individuals/km2 at 332 masl to 0.9 individuals/km2 at 1570 masl. Based on combining data sets in a gap analysis, we recommend conservation action focus on unprotected lowland forest to the south and west of the Cotacachi-Cayapas Ecological Reserve where hunting pressure is low and population densities of Ateles fusciceps are greatest.

The Transition to Agriculture at Dadiwan, People’s Republic of China

Recent excavations at the Dadiwan site in the western Loess Plateau, Gansu Province, People’s Republic of China (PRC), document the first continuous foraging-to-farming sequence in North China. The Dadiwan occupation began at about 80,000 BP and became regular by about 60,000 BP, probably before the arrival or evolution of modern Homo sapiens in North China. This record spans the transitions from nonintensive to intensive hunting and gathering and from intensive hunting and gathering to low-level Laoguantai food production and finally intensive Late Banpo, Neolithic agriculture. The intensive hunter-gatherer adaptation from which Dadiwan millet agriculture evolved did not develop at Dadiwan itself. Instead, it came south with intensive hunter-gatherer groups migrating out of the arid deserts north of the Yellow River, where the late Pleistocene–early Holocene North China Microlithic was common.

Hunting Intensity in the Suhuma Forest Reserve in the Sefwi Wiawso District of the Western Region of Ghana: A Threat to Biodiversity Conservation

Hunting intensity in the Suhuma Forest Reserve (SFR) in the Sefwi Wiawso District of the Western Region of Ghana has been investigated. The methodology involved the recording of signs of hunting activity using linetransects, and interviews with hunters. A total of 157 spent cartridges, 21 wire snares, presence of 17 hunters, four hunting camps, and two gunshots were recorded over a total of 14 km of transects walked. Ten species of mammals were hunted, notably the brush-tailed porcupine ( Atherurus africanus) , Pel’s flying squirrel (Anomalurus peli) , long-tailed pangolin ( Uromanis tetradactyla) , giant rat ( Cricetomys gambianus ), Maxwell’s duiker ( Cephalophus maxwelli) , bushbuck ( Tragelaphus scriptus ), bay duiker ( Cephalophus dorsalis ), royal antelope ( Neotragus pygmaeus ), western tree hyrax ( Dendrohyrax dorsalis ), and grasscutter ( Thryonomys swinderianus ). Wire snares and shotguns were the two main hunting methods employed, the former being used by all, and the latter by 34% of the hunters interviewed. Between 60 and 200 wire traps were set by each hunter. The results indicated a high hunting intensity in the Suhuma Forest Reserve. Some corrective measures have been recommended to ameliorate the problem. These measures include the initiation of public education and awareness programmes, establishment of task forces to check bushmeat hunting, execution of stricter law enforcement, and more punitive sanctions for offenders.

Effects of Trophy Hunting on Lion and Leopard Populations in Tanzania

Tanzania holds most of the remaining large populations of African lions (Panthera leo) and has extensive areas of leopard habitat (Panthera pardus), and both species are subjected to sizable harvests by sport hunters. As a first step toward establishing sustainable management strategies, we analyzed harvest trends for lions and leopards across Tanzania's 300,000 km(2) of hunting blocks. We summarize lion population trends in protected areas where lion abundance has been directly measured and data on the frequency of lion attacks on humans in high-conflict agricultural areas. We place these findings in context of the rapidly growing human population in rural Tanzania and the concomitant effects of habitat loss, human-wildlife conflict, and cultural practices. Lion harvests declined by 50% across Tanzania between 1996 and 2008, and hunting areas with the highest initial harvests suffered the steepest declines. Although each part of the country is subject to some form of anthropogenic impact from local people, the intensity of trophy hunting was the only significant factor in a statistical analysis of lion harvest trends. Although leopard harvests were more stable, regions outside the Selous Game Reserve with the highest initial leopard harvests again showed the steepest declines. Our quantitative analyses suggest that annual hunting quotas be limited to 0.5 lions and 1.0 leopard/1000 km(2) of hunting area, except hunting blocks in the Selous Game Reserve, where harvests should be limited to 1.0 lion and 3.0 leopards/1000 km(2) .

Genome-Wide Loss of Diversity in the Critically Endangered Hawaiian Monk Seal

Threatened species often exhibit low genetic diversity as a result of selective sweeps, historical bottlenecks, or persistent small population size. Whereas selective sweeps create localized reduction of variation at a chromosome, population bottlenecks result in the loss of rare alleles throughout the genome. Heterozygosity is lost more slowly and is severely impacted only when populations are small for an extended period of time. We test the hypotheses of selective sweep, historical bottleneck and persistently small population size to explain extremely low genetic diversity in the critically endangered Hawaiian monk seal (Monachus schauinslandi). Of 163 microsatellite loci isolated from the species’ genome, only 17 are polymorphic. Mapping 98 monomorphic and 12 polymorphic loci to 35 chromosomes throughout the dog genome, we reject the selective sweep hypothesis. Genotyping 2,423 Hawaiian monk seals at the 17 polymorphic loci plus a locus previously isolated from another pinniped species, we find evidence for a recent bottleneck (P = 0.04). This is consistent with historical records describing intense hunting in the 19th century; however, the bottleneck was not of sufficient severity and duration to explain the genome-wide depletion of genetic diversity (HO = 0.05; A = 1.1). Long-term population size restriction is a more likely explanation. Though at least two of the polymorphic loci appear to be candidates for selection, the low genetic diversity of the species may further threaten chances for survival of this critically endangered species in a changing world.

Effect of Small‐Scale Heterogeneity of Prey and Hunter Distributions on the Sustainability of Bushmeat Hunting

Bushmeat is the main source of protein and the most important source of income for rural people in the Congo Basin, but intensive hunting of bushmeat species is also a major concern for conservationists. Although spatial heterogeneity in hunting effort and in prey populations at the landscape level plays a key role in the sustainability of hunted populations, the role of small-scale heterogeneity within a village hunting territory in the sustainability of hunting has remained understudied. We built a spatially explicit multiagent model to capture the dynamics of a system in which hunters and preys interact within a village hunting territory. We examined the case of hunting of bay duikers (Cephalophus dorsalis) in the village of Ntsiété, northeastern Gabon. The impact of hunting on prey populations depended on the spatial heterogeneity of hunting and prey distribution at small scales within a hunting area. Within a village territory, the existence of areas hunted throughout the year, areas hunted only during certain seasons, and unhunted areas contributed to the sustainability of the system. Prey abundance and offtake per hunter were particularly sensitive to the frequency and length of hunting sessions and to the number of hunters sharing an area. Some biological parameters of the prey species, such as dispersal rate and territory size, determined their spatial distribution in a hunting area, which in turn influenced the sustainability of hunting. Detailed knowledge of species ecology and behavior, and of hunting practices are crucial to understanding the distribution of potential sinks and sources in space and time. Given the recognized failure of simple biological models to assess maximum sustainable yields, multiagent models provide an innovative path toward new approaches for the assessment of hunting sustainability, provided further research is conducted to increase knowledge of prey species' and hunter behavior.

Hunting differentially affects mixed‐sex and bachelor‐herds in a gregarious ungulate, the impala (Aepyceros melampus: Bovidae)

AbstractWe investigated herd‐sizes and herd‐compositions of Impala (Aepyceros melampus) inside a protected area [Lake Mburo National Park (LMNP) in western Uganda] and the unprotected adjacent ranchland [the Ankole Ranching Scheme (ARS)]. Impala experience intense hunting and poaching in the study area, and poaching is especially strong on the ARS. We found evidence for changes in overall group‐sizes in both mixed‐sex and pure bachelor herds between areas in and outside LMNP. Mixed‐sex herds strongly decreased in size outside the National Park, but bachelor herds even slightly increased in size. While the group‐composition of mixed‐sex herds was very similar in areas in and outside LMNP, bachelor herds comprised more yearlings and subadult males on the ARS. Our study suggests that effects of hunting and other human nuisance may differ between herd types: mixed herds probably decrease in size because females are more strongly hunted. Around LMNP, impala are usually hunted using nets and spears, thereby increasing the hunters’ chance of being injured. Poachers therefore prefer hornless females (and their calves), as it is less dangerous to handle net‐caught females than males. As a result, males are less hunted, but increased vigilance and, therefore, reduced aggression among the members of a bachelor herd, may account for the observed increase in herd sizes and changes in group‐compositions.

Wintering Areas and Recovery Rates of Brünnich’s Guillemots <i>Uria lomvia</i> Ringed in the Svalbard Archipelago

We mapped wintering areas and estimated the recovery rates of Brünnich’s guillemots (thick-billed murres) ringed in Svalbard during 1954–98. Recoveries were reported from Iceland, Greenland, and Newfoundland. An intensive hunt occurs annually off Greenland and Newfoundland, and more than 95% of the recovered birds were reported as shot. Birds recovered as immatures differed from birds recovered as adults in their temporal and spatial distribution. Immatures were more exposed to hunting because they arrived at the hunting areas earlier in the autumn and formed a higher proportion of the population in hunting areas farthest away from Svalbard. The recovery rate of birds ringed in Svalbard as chicks was comparable to the recovery rate reported from Canada. Interestingly, no Svalbard birds have ever been recovered in the southern part of the Barents Sea or along the Norwegian coast, suggesting that these areas are not important to the Svalbard population. The distribution of winter recoveries of birds ringed in Svalbard was compared to the winter recovery areas of Brünnich’s guillemots ringed elsewhere in the North Atlantic. Only birds ringed in Svalbard have been recovered in Iceland in winter.

Comment on “Towards a precautionary approach to managing Canada's commercial harp seal hunt” by Leaper et al.

Abstract Hammill, M. O., and Stenson, G. B. 2010. Comment on “Towards a precautionary approach to managing Canada's commercial harp seal hunt” by Leaper et al. – ICES Journal of Marine Science, 67: 321–322. The Objective-Based Fisheries Management used by Canada to manage the Northwest Atlantic seal hunt conforms to United Nations and Canadian Government precautionary approach frameworks in its structure and industry involvement. Managers and industry use clearly identified thresholds and harvest control rules to adjust quotas to respect the management framework. Although simulation testing is needed to evaluate management model performance under additional sources of uncertainty, this approach has successfully maintained the harp seal population at or near the highest level ever seen, during a period of intensive hunting.

Post-moult distribution and abundance of white-fronted geese and Canada geese in West Greenland in 2007

Rapid increases in North American Canada geese (Branta canadensis) summering in West Greenland since the mid-1980s compare with declines in the endemic population of white-fronted geese (Anser albifrons flavirostris) nesting in the same region since 1999 (wintering in Europe). To provide information on the distribution and abundance of the two species in Greenland during the prelude to the autumn migration back to winter quarters, we here report on the first ever post-moult aerial surveys of West Greenland between 64° and 73°N (from regular transects and transit reconnaissance flights in August 2007), which located 1888 Greenland white-fronted geese and 6071 Canada geese. Strip transect surveys found 733 Greenland white-fronted geese and 1318 Canada geese in the 993 km2 surveyed, which, given a white-fronted goose global population of 23 200 in winter 2007/08, suggests more than 41 500 Canada geese inWest Greenland post-moult in 2007. Virtually no geese were found south of 66°N. The Eqalummiut nunaat–Nassuttuup nunaa and Naternaq Ramsar wetlands of international importance, and lowland Disko Island, Saqqaqdalen and Svartenhuk supported the highest densities of both species. Results confirmed that areas important for both species during spring, nesting and moulting periods retain high densities of post-moulting geese. Canada and white-fronted geese rarely occurred together within 2.5 km ¥ 400 m transect sectors, as found during breeding surveys. Only in western Svartenhuk and western Disko were there Canada goose concentrations that could potentially support an intensive autumn hunt, whilst avoiding disturbance to white-fronted geese.

The Importance of Hunting and Habitat in Determining the Abundance of Tropical Forest Species in Equatorial Guinea

ABSTRACTUnderstanding the impact of hunting on wildlife populations is crucial to achieving sustainability and requires knowledge of prey abundance responses to different levels of exploitation. While the abundance of primates has been shown to respond independently to hunting and habitat, habitat is rarely considered simultaneously when evaluating the impacts of hunting. Furthermore, the importance of these two factors in determining the abundance of other species has not been well investigated. We evaluate the independent effects of hunting and habitat on the abundance of a diverse assemblage of species, using a series of predictions and data from a study in Equatorial Guinea. Line transect surveys in sites of varying hunting intensity and habitat, and weekly interviews with hunters on current hunting effort in each site, were conducted. We also consider the role of past hunting, and discuss the interrelationships between hunting and habitat variables. We show that for primates, hunting is important in determining abundance, while for rodents and duikers, habitat is more important. Our findings show that the effects of hunting and habitat on abundance vary greatly between species, are often confounded and require an approach that isolates their independent effects to determine the true impact of hunting. Conservation managers must consider and incorporate habitat heterogeneity when managing hunting systems, taking into account the way in which the relative importance of these factors can vary between species.

Communautés locales et gibiers dans la région de Daraina, extrême Nord-Est de Madagascar

Wild meats take part in the daily protein sources for many Malagasy rural communities. Many animal species are affected by hunting, which is practiced during almost all seasons in Madagascar. In the Daraina region, animal groups hunted by local people are mainly mammals, birds, fishes, and reptiles. As the natural habitats within this region are actually highly perturbated by human activities, and as this region shows a high population growth, hunting may constitute a severe threat for many species. Sustainable management of these later depends on local population awareness regarding the threats of intensive hunting on animals as well as on the natural ecosystems.

Recent and Chronic Exposure of Wild Ducks to Lead in Human-modified Wetlands in Santa Fe Province, Argentina

Poisoning of waterfowl due to ingestion of lead pellets is a worldwide problem in areas that are subject to hunting. No studies have assessed exposure of waterbirds to this heavy metal in Argentina, in spite of intense hunting activity, and the fact that only lead ammunition is commercially available. The objective of this study was to evaluate duck exposure to lead by examining gizzard and bone samples collected from 30 wild ducks, 16 Rosy-billed Pochard (Netta peposaca), and 14 Fulvous Whistling-Duck (Dendrocygna bicolor), provided by hunters in northern Santa Fe Province, Argentina, in July 2007. Radiographs, followed by dissection of the gizzards, showed that 31% of the Rosy-billed Pochards and 29% of the Fulvous Whistling-Ducks had ingested lead pellets (between one and four per animal). Lead in bone was found at concentrations associated with detrimental health effects. In spite of the small number of samples in this project, these results indicate high levels of lead exposure (both recent and chronic) in these species. This is the first report of a problem in Argentina that could represent a threat to the health and conservation of native aquatic species, their predators, and the wetlands they inhabit.

Factors that lead to a decline in numbers of Mongolian marmot populations

Using a series of country-wide transects and a questionnaire administered to those with knowledge of marmot populations, we estimated that there are now about 8 million marmots in Mongolia. Our survey and previous studies of maximal marmot abundances produced estimates that ranged from 21 to 24 million animals. Our research showed that the decline in marmot populations from the beginning of 1990-th to 2007 was mostly due to increased hunting pressure. Hunting pressure increased when foreign buyers purchased marmot pelts unlimited offering significantly higher prices than offered in the past. These higher prices lead to the initiation of hunting during the spring reproductive season of marmots and the increased use of traps and snares to capture marmots. Greater access to automobiles and an improved highway system lead to more widespread and intense hunting of marmots than in the past. In the 7 years after 2000 there was increased subsistence hunting of marmots for food, fur, and traditional medicines. A spring drought during portions of the 7 year period may have deceased marmot numbers. Also contributing to the decline of marmots during this period was an increase in the number of dogs used by shepherds — dogs that preyed on marmots.

Sport Hunting, Predator Control and Conservation of Large Carnivores

Sport hunting has provided important economic incentives for conserving large predators since the early 1970's, but wildlife managers also face substantial pressure to reduce depredation. Sport hunting is an inherently risky strategy for controlling predators as carnivore populations are difficult to monitor and some species show a propensity for infanticide that is exacerbated by removing adult males. Simulation models predict population declines from even moderate levels of hunting in infanticidal species, and harvest data suggest that African countries and U.S. states with the highest intensity of sport hunting have shown the steepest population declines in African lions and cougars over the past 25 yrs. Similar effects in African leopards may have been masked by mesopredator release owing to declines in sympatric lion populations, whereas there is no evidence of overhunting in non-infanticidal populations of American black bears. Effective conservation of these animals will require new harvest strategies and improved monitoring to counter demands for predator control by livestock producers and local communities.

Long-Term Changes in Game Species Over a Long Period of Transformation in the Iberian Mediterranean Landscape

Agricultural change has transformed large areas of traditional farming landscapes, leading to important changes in the species community assemblages in most European countries. We suspect that the drastic changes in land-use that have occurred in Andalusia (southern Spain) over recent decades, may have affected the distribution and abundance of game species in this region. This article compares the distribution of the main game species in Andalusia during the 1960s and 1990s, using data from maps available from the Mainland Spanish Fish, Game and National Parks Service and from recent datasets on hunting yield distributions, respectively. Big-game and small-game species were significantly segregated in southern Spain during the 1990s, as two clearly independent chorotypes (groups of species whose abundances are similarly distributed) were obtained from the classification analysis. In contrast, big-game and small-game species were not significantly segregated several decades ago, when there was only one chorotype consisting of small-game species and wild boar. The other three ungulates did not constitute a significant chorotype, as they showed positive correlations with some species in the group mentioned above. These changes seem to be a consequence of the transformations that have occurred in the Iberian Mediterranean landscape over the last few decades. The abandoning of traditional activities, and the consequent formation of dense scrubland and woodland, has led to an expansion of big-game species, and a decrease of small-game species in mountain areas. Moreover, agricultural intensification has apparently depleted small-game species populations in some agricultural areas. On the other hand, the increasingly intensive hunting management could be artificially boosting this segregation between small-game and big-game species. Our results suggest that the conservation and regeneration of traditional agricultural landscapes (like those predominating in the 1960s) should be a priority for the conservation of small-game species.