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.
Although eating clay at licks (a form of geophagy) has been described, there are few behavioral data on temporal patterns, social interactions, species associations, or reactions to potential predators. We examined the behavior of nine species of macaws, parrots, and parakeets at the Machiguenga Ccolpa, a clay lick on the Rio Manu, Peru in the dry season. Three distinct mixed-species groups used the licks: in the early morning (parrots and small macaws), in mid-morning (large macaws), and in the early afternoon (parakeets), although the latter two groups used the licks at other times of day as well. The first parrots to begin eating at the lick in the early morning were yellow-crowned parrots (Amazona ochrocephala) and dusky-headed parakeets (Aratinga weddellii), followed by blue-headed parrots Pionus sordidus, and then by mealy (Amazona farinosa) and orange-cheeked (Pionopsitta barrabandi) parrots, and chestnut-fronted macaws (Ara severa). Although blue-headed parrots fed in dense groups of over 50, the others rarely exceeded 20 individuals. Scarlet macaws (A. macao) sometimes fed alone or joined the early morning groups, but most associated with a large group of red and green macaws (A. chloroptera) that arrived, often scaring off the smaller birds. On average, about 100 macaws and parrots fed in the early morning, macaw feeding groups averaging just over 40, and the parakeets averaged over 70. Average time at the lick ranged from 28 min for yellow-crowned parrots to 47 min for tui parakeets. Of the early morning group, blue-headed and mealy parrots were the most aggressive and orange-cheeked parrots were the least aggressive. Red and green macaws were more aggressive than scarlet macaws; the parakeets were equally aggressive. All species had more aggressive interactions with conspecifics than with other species. Responses to intruders and predators varied by species of parrot/macaw and type of intruder. In response to intruders or loud calls, responses could be partial (some individuals flew away, circled, and returned), temporary (all individuals flew away but returned within a few minutes), or total (all flew away and abandoned feeding for at least a half hour). The large macaws showed the lowest rate of total abandonment and the parakeets showed the highest. People passing up or down river in boats scared birds from the lick. The local residents (Machiguenga tribespeople in boats) elicited a much greater response than did the researchers. In the recent past, macaws and parrots were hunted for food, feathers, and the pet trade, and the birds response, as well as the presence of parrot and macaw feathers in local villages we visited, suggests some continued exploitation, or a long-term memory in the birds.Communicated by R.F. Oliveira  相似文献   

2.
Capsule French breeding populations of hunted waterbirds have more negative long-term population trends than closely related non-hunted species.

Aims To assess the relative fate of breeding populations of hunted and non-hunted waterbird species in France.

Methods We compared long-term population growth rates of hunted versus non-hunted waterbirds using two large-scale and long-term national surveys.

Results Waterbirds globally displayed long-term increases in population sizes most likely driven by their positive response to the implementation of numerous protected areas over remnant wetlands across the country since the early 1970s. In contrast, hunted species revealed more negative trends compared to non-hunted species.

Conclusion A causal relationship between hunting and population dynamics is not demonstrated here, but the results are consistent with species' breeding populations being negatively affected, on average, if they are hunted.  相似文献   

3.
The relative abundance of an ungulate community in hunted and non-hunted areas was studied in Calakmul, a tropical forest in southern Mexico that includes a 723,815 ha Biosphere Reserve where no hunting is allowed and communal lands where hunting activity does take place. Tapir, white-lipped peccary (WLP), collared peccary, two species of brocket deer and white-tailed deer were the focal species. Relative abundance of ungulates was obtained by counting tracks along transects in three hunted sites and in the southern core area of the Calakmul Biosphere Reserve, a enforced part of the protected area of 350,000 ha where no hunting has been-permitted since 1989. A total of 1708 ungulates tracks were obtained along 206.1 km (n = 90 transects) divided among the four sites. Relative abundance of the species was estimated from the track encounter rate (TER) calculated as the number of tracks per species encountered per km of transect. No significant differences in brocket deer and collared peccary TER was found among hunted and non-hunted areas. TER for WLP was significant higher in the non-hunted area, while TER for white-tailed deer and tapir was significant higher in hunted sites. Hunting activity affected the ungulate species in Calakmul differently. Brocket deer, white-tailed deer and collared peccary are more resistant species toward the hunting pressure than the WLP, who needs an immediate protection plan throughout Calakmul. Hunting areas are important habitat refuges for tapir populations and they should be protected in these areas.
Resumen La abundancia relativa de seis especies de ungulados fue obtenida a través de conteos de huellas a lo largo de transectos en tres sitios con cacería y en la parte sur de la Reserva de la Biosfera de Calakmul, una área de alrededor de 350,000 ha donde la cacería ha sido prohibida desde 1989. Tapir, pecarí de labios blancos, pecarí de collar, dos especies de venados temazates y el venado cola blanca fueron las especies estudiadas. Un total de 1708 huellas de ungulados fueron obtenidos a lo largo de 206.1 km (90 transectos) divididos en los cuatro sitios. La abundancia relativa de las especies fue estimada por medio de la tasa de encuentro de huellas (TEH) calculado como el número de huellas encontradas por km de transecto recorrido. La TEH de los venados temazates y el pecarí de collar fue similar entre las áreas con cacería y sin cacería. La TEH para el pecarí de labios blancos fue significativamente mayor en el área sin cacería, mientras que la TEH del venado cola blanca y el tapir fueron significativamente mayor en los sitios con cacería. La actividad de cacería afecta a las especies de ungulados diferente en la región de Calakmul. Los venados temazates, el venado cola blanca y el pecarí de collar están resistiendo mejor la presión de cacería que el pecarí de labios blancos quien necesita un plan inmediato de protección en toda el área. La evidencia sugiere que las áreas con cacería en este estudio son importantes para las poblaciones de tapir, y que se debe prestar atención a su protección en dichas áreas.
  相似文献   

4.
Analysis of sample survey data on the species composition of waterfowl kill for resident and nonresident hunters for provinces of Canada during 1974 and 1975 showed that a successful game bird hunter who hunted in more than one area (degree block) had both a higher average season kill and more successful days of hunting in which one or more birds were bagged, than one who hunted in the same area during the season. Adjustment for days hunted resulted in a higher daily hunting for those who hunted in more than one degree block. However, the higher kill of the successful hunter is attributable more to a larger number of days hunted than to a larger kill per successful day. Also, hunters hunting in more than one degree block had their successful hunting days more evenly spread across the season. The estimates of kill per successful hunter and days hunted for stratified sampling by areas of hunting were considerably more efficient than simple random sampling.  相似文献   

5.
Half of all artiodactyls (even-toed hoofed mammals) are threatened with extinction, around double the mammalian average. Here, using a complete species-level phylogeny, we construct a multivariate model to assess for the first time which intrinsic (biological) and extrinsic (anthropogenic and environmental) factors influence variation in extinction risk in artiodactyls. Globally artiodactyls at greatest risk live in economically less developed areas, have older weaning ages and smaller geographical ranges. Our findings suggest that identifying predictors of threat is complicated by interactions between both biological and anthropogenic factors, resulting in differential responses to threatening processes. Artiodactyl species that experience unregulated hunting live in significantly less economically developed areas than those that are not hunted; however, hunted species are more susceptible to extinction if they have slower reproductive rates (older weaning ages). In contrast, risk in non-hunted artiodactyls is unrelated to reproductive rate and more closely associated with the economic development of the region in which they live.  相似文献   

6.
Hunting in tropical forests decimates large mammals, and this may have direct and indirect effects on other trophic levels and lead to trophic cascades. We compared replicated sites of hunted and protected forests in southeastern Nigeria, with respect to community composition of primates, other mammals, birds, plant seedlings, and mature trees. We make predictions regarding the community composition at the different trophic levels. In forests where large primates are rare, we hypothesize that their ecological role will not be fully compensated for by small frugivores. We apply multivariate methods to assess changes in community composition of mammals, birds, and seedlings, controlling for any differences between sites in the other groups, including mature trees. Medium and large (4–180 kg) primates were much rarer in hunted sites, while porcupine and rock hyrax increased in abundance with hunting. In contrast, the community composition of birds was similar in both types of forests. Seedling communities were significantly related to the community composition of mammals, and thus strongly affected by hunting. In protected forests primate dispersed plant seedling species dominated, whereas in hunted forests the seedling community was shifted towards one dominated by abiotically dispersed species. This was probably both a consequence of reduced seed dispersal by primates, and increased seed predation by rodents and hyrax. Hence we found no evidence for buffering effects on tree regeneration through functional compensation by non‐hunted animals (such as birds). Our results highlight how seedling communities are changed by the complex plant–animal intera ctions, triggered by the loss of seed dispersers. The results predict a rarity of primate‐dispersed trees in future tropical forest canopies; a forest less diverse in timber and non‐timber resources.  相似文献   

7.
Vertebrate responses to hunting are widely variable for target and nontarget species depending on the history of hunting and productivity of any given site and the life history traits of game species. We provide a comprehensive meta-analysis of changes in population density or other abundance estimates for 30 mid-sized to large mammal, bird and reptile species in 101 hunted and nonhunted, but otherwise undisturbed, Neotropical forest sites. The data set was analyzed using both an unnested approach, based on population density estimates, and a nested approach in which pairwise comparisons of abundance metrics were restricted to geographic groups of sites sharing similar habitat and soil conditions. This resulted in 25 geographic clusters of sites within which 1811 population abundance estimates were compared across different levels of hunting pressure. Average nested changes in abundance across increasingly greater levels of hunting pressure ranged from moderately positive to highly negative. Populations of all species combined declined across greater differences in hunting pressure by up to 74.8 percent from their numeric abundance in less intensively hunted sites, but harvest-sensitive species faired far worse. Of the 30 species examined, 22 declined significantly at high levels of hunting. Body size significantly affected the direction and magnitude of abundance changes, with large-bodied species declining faster in overhunted sites. Frugivorous species showed more marked declines in abundance in heavily hunted sites than seed predators and browsers, regardless of the effects of body size. The implications of hunting for seed dispersal are discussed in terms of community dynamics in semi-defaunated tropical forests.  相似文献   

8.

Overhunting is a leading contemporary driver of tropical forest wildlife loss. The absence or extremely low densities of large-bodied vertebrates disrupts plant-animal mutualisms and consequently degrades key ecosystem services. Understanding patterns of defaunation is therefore crucial given that most tropical forests worldwide are now “half-empty”. Here we investigate changes in vertebrate community composition and size structure along a gradient of marked anthropogenic hunting pressure in the Médio Juruá region of western Brazilian Amazonia. Using a novel camera trapping grid design deployed both in the understorey and the forest canopy, we estimated the aggregate biomass of several functional groups of terrestrial and arboreal species at 28 sites along the hunting gradient. Generalized linear models (GLMs) identified hunting pressure as the most important driver of aggregate biomass for game, terrestrial, and arboreal species, as well as nocturnal rodents, frugivores, and granivores. Local hunting pressure affected vertebrate community structure as shown by both GLM and ordination analyses. The size structure of vertebrate fauna changed in heavily hunted areas due to population declines in large-bodied species and apparent compensatory increases in nocturnal rodents. Our study shows markedly altered vertebrate community structure even in remote but heavily settled areas of continuous primary forest. Depletion of frugivore and granivore populations, and concomitant density-compensation by seed predators, likely affect forest regeneration in persistently overhunted tropical forests. These findings contribute to a better understanding of how cascading effects induced by historical defaunation operate, informing wildlife management policy in tropical peri-urban, rural and wilderness areas.

  相似文献   

9.
A considerable proportion of tropical protected areas are Sustainable Use Reserves (SURs), where socio-biodiversity protection and sustainable resource extraction are the main goals. Subsistence hunting is the most widespread form of subcanopy forest resource extraction, and often depletes game populations within SURs, but the degree to which these extractive activities are sustainable remains questionable. To assess patterns of hunting sustainability within SURs, we systematically examined the local ecological knowledge of 211 resident hunters living in 93 communities located within and immediately outside nine SURs of Brazilian Amazonia. We used mixed models to assess the effects of settlement features (distance to reserve boundaries, size, age, distance to urban centers, and extent of floodplain areas) on local perceptions of game abundance, the prey profile of the most consumed game species, and overall levels of local game depletion. Hunters consistently reported that game populations were less impacted within communal catchment areas containing larger amounts of floodplain habitat and farther from urban centers. In these areas the overall game abundance was perceived to be higher, low-fecundity species were most consumed, and harvest-sensitive species were least depleted. Local SUR communities within this context accrued higher benefits from higher wild-meat availability, but settlement age and size had no effects on hunted species. Evidence-based conservation management plans in tropical protected areas should focus on reducing wild meat demand in urban areas and managing both, the local aquatic animal protein in floodplain areas to relieve pressure on terrestrial game species, and the offtake of game populations at inland sites lacking access to aquatic animal protein.  相似文献   

10.
To assess ecological consequences of bushmeat hunting in African lowland rainforests, we compared paired sites, with high and low hunting pressure, in three areas of southeastern Nigeria. In hunted sites, populations of important seed dispersers—both small and large primates (including the Cross River gorilla, Gorilla gorilla diehli)—were drastically reduced. Large rodents were more abundant in hunted sites, even though they are hunted. Hunted and protected sites had similar mature tree communities dominated by primate-dispersed species. In protected sites, seedling communities were similar in composition to the mature trees, but in hunted sites species with other dispersal modes dominated among seedlings. Seedlings emerging 1 year after clearing of all vegetation in experimental plots showed a similar pattern to the standing seedlings. This study thus verifies the transforming effects of bushmeat hunting on plant communities of tropical forests and is one of the first studies to do so for the African continent.  相似文献   

11.
Wild boar have been increasing in numbers all over Western Europe in the last 30 years. The species is a major pest for agriculture, but it has a high value as a game species, and in Italy, as in several other countries, it is traditionally hunted in drive hunts by hunting teams with several dogs. This hunting method can have disruptive effects on the demography and spatial behaviour of wild boar, especially family groups. We conducted a 2-year study (2003 and 2004) to determine the effects of drive hunt disturbance on the spatial behaviour of wild boar family groups in the Northern Apennines (central Italy). Twenty wild boar belonging to ten family groups were ear tagged with a radio device. We located resting sites daily and used intensive tracking sessions during drive hunts. Three seasons were determined: pre-hunting, hunting and post-hunting. A general pattern of increased spatial instability during the hunting season was shown. Resting ranges were larger, and resting sites were more interspersed. Distances between consecutive resting sites were greater during the hunting season and, especially, on hunting days. The displacement of family groups caused by drive hunts was generally short lived except for those groups that were repeatedly hunted and so abandoned their pre-hunt (native) range. During drive hunts, wild boar showed a moderate tolerance to hunting disturbance, and only family groups which were directly chased by dogs escaped or altered their behaviour. The response of wild boar to hunting disturbance seemed to be highly related to the degree of hunting pressure combined with individual variability. The impact on wild boar behaviour should be reduced, above all by avoiding repeated hunts in the same areas within a short period and by employing well-trained hounds.  相似文献   

12.
The impacts of human pressure, habitat changes, and efficiency of conservation measures on the non-passerine bird community were assessed in the Sudanian belt of Burkina Faso. Three regions with increasingly large protected areas and higher conservation status were compared. In each region, natural savanna woodlands were also compared to traditionally cultivated areas. Six groups of diurnal raptors and six groups of other large bird species were counted along 167 5-km transect counts during the dry season. Within savanna woodlands, the only significant and consistent declines from the little disturbed Eastern National Parks to the more populated and exploited Western forest reserves were those of the largest terrestrial game birds (Guinea fowl, Bustard, Ground Hornbill), eagles and vultures, which became virtually extinct in the least protected areas. Although some species groups maintained substantial, if not higher populations in cultivated areas (rollers, non-game terrestrial birds, several raptors), the overall abundance of both raptor and non-raptor species declined markedly (50–65%) from natural savanna woodlands to tree-dotted cultivated and fallow fields. Again large game birds, eagles and vultures were absent from every agricultural areas censused. Yet, all of them were still commonly recorded in the same natural and cultivated areas during surveys I conducted in the same regions from 1968 to 1973. The main factors correlated with large bird extinctions or declines from national parks to mere forest reserves and from natural woodlands to fields were first related to hunting, then to habitat degradation and fragmentation through intensive cattle grazing and wood cutting and extension of cultivated areas.  相似文献   

13.
Hunting often impacts rain forest mammal communities but little is known about its indirect effects on other taxa. We examined dung beetle assemblages using pitfall and flight-intercept traps at six rain forest sites in Panama that ranged in hunting intensity. Heavily hunted sites showed altered community composition, significantly fewer species (based on rarefaction), and lower abundances of dung beetles than did sites with little hunting. Our results suggest that intensive hunting affects nontarget forest taxa and is potentially altering ecosystem functioning.  相似文献   

14.
Many animals can adjust their behavioral strategies to reduce predation risk. We investigated whether rain forest monkeys and duikers alter their antipredatory behavior in response to hunting by humans in southwestern Gabon. We compared monkey and duiker responses to human observers in an area where hunting is prohibited, to those in a nearby area where hunting pressure is moderate but spatially variable. The results of our study indicate that monkeys become more secretive when hunted, commencing alarm calls only when at a certain distance (typically > 50 m) from humans. We found no difference in monkey group size between hunted and no-hunting areas. In no-hunting areas, duikers often freeze in response to approaching observers, but in hunted areas they abandon this strategy and rapidly flee from humans. Duikers also whistle more often in areas where they are hunted frequently. Our findings have at least two important implications. First, behavioral observations of monkeys and duikers may be useful in gauging local hunting intensity in African rain forests. Second, duiker densities are likely to be overestimated in hunted areas, where they more readily flee and whistle, and underestimated in no-hunting areas, where they rely on freezing behavior to avoid detection. Because behavioral adaptations to hunting vary both among species and localities, these differences should be considered when attempting to derive population-density estimates for forest wildlife.  相似文献   

15.
Hunting, although prohibited, is widely practiced by the rural inhabitants settled along the Transamazon highway. In 1997 and 2000, we investigated subsistence hunting in Uruará, a township located on an Amazonian pioneer front (Brazil). We analyze hunting practices, game yield, hunting efficiency and their relation to forest coverage rate. The hunting methods were stand hunting (55.5%) and beating (44.5%). Paca (Agouti paca), tatus (Dasypus novemcinctus and D. septemcinctus), and collared peccary (Pecari tajacu) were the most frequently hunted species, supplying 68% of the gross game weight. Beating was significantly more efficient than stand hunting (3 vs. 1.9 kg/hunter/h, Mann–Whitney U test, P=0.02). Hunting territories were classified in three categories according to forest coverage rate. The higher the forest coverage rate the larger was the harvested species and the more efficient the hunter (Kruskal–Wallis test P=0.01). Considering the ecological and demographic changes in this pioneer settlement, development of a viable plan for game management and forest preservation is of great importance.  相似文献   

16.
A comparative study of species assemblages and population densities was conducted on Amazonian monkey communities in 16 areas, ranging from 3°S latitude in northern Peru to 18°S latitude in southern Bolivia. The habitats ranged from several types of tropical rain forest in the more northern latitudes to dry, deciduous forest in the southernmost study area. The monkey populations of three of the study areas have historically received light hunting pressure; the rest have been moderately to heavily hunted. A transect census technique was used to estimate the relative and absolute densities of all diurnal monkey species except Cebuella pygmaea. The number of coexisting monkey species ranged from 4–6 in the southern areas to 12–14 in the northern areas. The reduction in species richness in central and southern areas of Bolivia is probably attributable to several inimical habitat factors. Predation by humans was found to be the single most important factor affecting monkey densities. Monkey densities, and especially biomasses, were much lower in areas not protected from hunting than in protected areas. Hunting did not affect all species equally. Larger-sized species are hunted more and have severely reduced numbers in unprotected areas, whereas the densities of smaller species are not noticeably diminished in unprotected areas. Large, herbivorous monkey species contributed the major proportion of the total monkey biomass in protected areas. The strong influence of hunting has largely obscured the effects of other factors on population densities.  相似文献   

17.
We censused primate populations at three non-hunted 'terra firme' forests of south-eastern Colombian Amazonia. The aggregate biomass densities of diurnal primates at all sites were amongst the lowest recorded for any non-hunted forest in western Amazonia and elsewhere in the Neotropics. Densities of red howler monkeys were low, as is typical in Amazonian terra firme forests far removed from white-water rivers, and densities of woolly monkeys were 1.5-3.5 times lower than those estimated for this species in central-western Brazilian Amazonia. Densities of small to mid-sized primates except for brown capuchins (Cebus apella) and white-faced capuchins (Cebus albifrons) were similar to those of other oligotrophic Amazonian forest sites. Our results are in agreement with other studies showing that terra firme forests of lowland Amazonia typically sustain a low biomass density of primates and other mid-sized to large vertebrates. Large reserves are therefore required to assure the viability of primate populations in oligotrophic systems. Given the escalating negative impacts of human habitat disturbance and hunting in Colombian Amazonia, we urge that a baseline sampling protocol to quantify the abundance and distribution of the harvest-sensitive vertebrate fauna be established within protected areas and the large indigenous reserves so that conservation efforts can be defined and implemented.  相似文献   

18.
We identified species‐ and community‐level dietary characteristics for a species‐rich Amazonian parrot assemblage to determine relationships among dietary metrics and use of geophagy sites. Previous studies suggest that soil is consumed at geophagy sites in this region mainly to supplement dietary sodium. We accumulated 1400 feeding records for 16 parrot species over 2 yr and found that seeds, flowers, and fruit pulp featured prominently in diets, while bark, insects, and lichen were consumed in small quantities. Food availability across 1819 trees was measured, and we found that flower availability was highest in the dry season and fruit production peaked in the wet season, but that phenology patterns of the 20 most commonly foraged plant species suggest no serious food bottlenecks. Partitioning of available food resources among the 13 most commonly encountered parrots is suggested by an ordination analysis (DCA), which placed the large macaws (Ara) with the Amazona parrots at the ‘primary forest’ end of a dietary resource axis and four smaller species at the ‘successional forest’ end of the axis. Parrot species associated with successional forest also consumed less plant species overall. Furthermore, these parrot species consuming successional forest resources had higher claylick visitation rates than those consuming primary forest resources suggesting they derive the greatest benefits from soil consumption.  相似文献   

19.
We evaluated predictions that hunters favor lianas, large seeds, and seeds dispersed by bats, small birds, and mechanical means for seedling banks in central Panama. We censused 3201 trees in 20 1-ha plots and 38,250 seedlings in the central 64 m2 of each plot. We found significant differences in the species composition of the seedling bank between nine protected sites in the Barro Colorado Nature Monument and 11 hunted sites in the contiguous Parque Nacional Soberanía. Lianas, species with large seeds, and species with seeds dispersed by bats, small birds, and mechanical means were all overrepresented at hunted sites. The latter two findings could also be evaluated relative to the species composition of reproductively mature adults for canopy trees. The tree species present in the seedling bank had significantly heavier seeds than the tree species present as adults at hunted sites but not at protected sites. The representation of seed dispersal modes among the species present in the seedling bank did not reflect pre-existing differences in the local species composition of adults. We hypothesize that hunting large seed predators favors large seeds by reducing predation and increasing survival. We also hypothesize that the harvest of large birds and mammals that disperse many seeds favors other species whose seeds are dispersed by bats, small birds, and mechanical means. This process also favors lianas because the seeds of disproportionate numbers of liana species are dispersed by wind.  相似文献   

20.
The red-legged partridge (Alectoris rufa) is abundant in a number of regions in Spain and one of the most commonly hunted small game species in the country. Partridge hunting generates substantial income in rural areas where agriculture is less profitable. A traditional hunting method, reclamo hunting, is currently under revision by the European Commission's (EC) Birds Directive because hunting may fall within the reproduction period of the species. So far, only limited data on the reproductive phenology of the species exist to inform a policy change. In this study, we present reproduction data for red-legged partridges from 9 hunting estates in Andalusia during 1 year, and over 3 consecutive seasons from a control estate. We used direct nest and partridge chick covey observations to estimate 165 egg-laying dates. We found significant differences between sites related to altitude during reproduction periods. Using our pooled data, we showed that reproduction occurred between the last 10 days in January and the middle of February; beyond 31 January we observed an exponential increase in birds reproduction. According to these data and current EC legislation, reclamo hunting should not extend beyond 31 January. © 2012 The Wildlife Society.  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