共查询到20条相似文献，搜索用时 15 毫秒
1.
Norberto Asensio Warren Y. Brockelman Suchinda Malaivijitnond Ulrich H. Reichard 《Biotropica》2014,46(4):461-469
Core areas represent small regions within animal home‐ranges intensively used during a given period of time. We assessed the quality of core areas relative to the rest of the home‐ranges (i.e., non‐core areas) of 11 groups of the territorial and highly frugivorous white‐handed gibbon (Hylobates lar) over a short‐time scale to reflect temporarily available resources. Weekly core areas included consistently higher densities of the gibbons' important foods compared to non‐core areas. Gibbon core areas partially overlapped at 46 percent with a model comprising the best hypothetical core areas based on a concentration map of available food sources. In addition, a maximization ratio estimated by dividing the cumulative dbh covered by gibbon core areas and the model reached an intermediate value. Gibbon core areas only partially mirrored food distribution probably because they represent a trade‐off between covering regions with important food locations and areas needed for other biologically relevant activities such as territory defense. Results do not support the concept that core areas can represent the minimum area requirement that would allow a gibbon group to survive and reproduce successfully irrespective of the time period considered, which indicates that core areas alone should not be treated as a conservation target. 相似文献
2.
Although members of the family Hylobatidae are known to be monogamous, adult white-handed gibbons ( Hylobates lar ) at Khao Yai National Park, Thailand, also show multimale groups and polyandry. A need for more than one male to successfully raise offspring cannot explain the occurrence of polyandry in these territorial primates, because direct paternal care is absent in this species. We hypothesize that polyandry is primarily related to costs/benefits for males of cooperatively defending a female and/or resources; our prediction was that polyandry would become more frequent with increasing costs of female/resource defense. We measured the ecological quality of seven gibbon home ranges over a 3-yr period (2001–2003) to investigate how resource availability affected the probability of polyandry, and found a significant negative relationship between home range quality and home range size. Larger home ranges were of lower quality. As predicted, groups living on larger, poorer home ranges also experienced longer periods of polyandry. In forest areas of comparatively low quality, acquiring and maintaining a large home range that includes enough resources for a female to reproduce steadily may surpass a single male's capacity. Our model of cooperative male polyandry was supported by preliminary data of shared territorial defense and access to the female. However, interaction proportions were strongly skewed, and female's primary male partners monopolized grooming and mating. Nevertheless, a primary male on a large territory may benefit from the presence of a secondary male with aid in territorial/female defense, whereas a secondary male may gain by avoiding high dispersal costs. 相似文献
3.
Shea E. Flanagan Michael B. Brown Julian Fennessy Douglas T. Bolger 《African Journal of Ecology》2016,54(3):365-374
Conservation translocation is a management technique employed to introduce, re‐introduce or reinforce wild animal and plant populations. Giraffe translocations are being conducted throughout Africa, but the lack of effective post‐translocation monitoring limits our ability to assess translocation outcomes. One potential indicator of translocation success is the establishment of characteristic movement and home range behaviour in the new location. We analysed the post‐translocation movement patterns of six Global Positioning System‐collared Angolan giraffes (Giraffa camelopardalis angolensis) in three regions of Namibia. We estimated home range size with minimum convex polygon (MCP) and adaptive local convex hull estimators, and assessed home range behaviour with the localizing tendency model and a home range Monte Carlo bootstrap analysis. Four of the six giraffes appeared to establish home ranges, indicating short‐term translocation success. The other two giraffes exhibited long‐distance linear movements throughout the observation period, suggesting they did not establish home ranges. Home range sizes varied greatly among regions. Our results suggest monitoring translocated animals for the establishment of characteristic movement behaviour could be a useful early indicator of translocation success. 相似文献
4.
Frugivores with disparate foraging behavior are considered to vary in their seed dispersal effectiveness (SDE). Measured SDEs for gibbons and macaques for a ‘primate‐fruit’ were comparable despite the different foraging and movement behavior of the primates. This could help facilitate fruit trait convergence in diverse fruit–frugivore networks. 相似文献
5.
Karin Louise Hartman Marc Fernandez Anja Wittich José Manuel N. Azevedo 《Marine Mammal Science》2015,31(3):1153-1167
Knowledge of the residency patterns of marine mammals is an important element for management and conservation strategies. Here we investigate a population of Grampus griseus off Pico Island, Azores. Our data set covers the period 2004–2007, based on at‐sea observations of 1,250 individually identified animals, 303 of known or assumed sex. Using photo identification and GPS locations we calculated mean monthly sighting rates and lagged identification rates to analyze temporal patterns, and estimated kernel density to study the home range. Our results show site fidelity and relatively restricted home ranges, which corroborate the existence of a resident population on the study site. We further document sex differences, including a higher number of males present in the area at any given time but females staying for longer consecutive periods, and male home ranges with significantly less overlap than those of females. These observations are consistent with a mating system based on multimale pods defending areas where females periodically return. We hypothesize that squid distribution is a major factor in structuring these patterns. These findings reinforce the need for a precautionary management approach that would include limiting pressure from commercial activities. 相似文献
6.
New technologies for quantifying animal locations enable us to document habitat‐selection patterns of cryptic taxa in extraordinary detail. Northern bluetongues (Tiliqua scincoides intermedia) and centralian bluetongues (Tiliqua multifasciata) are large heavy‐bodied scincid lizards that are broadly sympatric in the wet–dry tropics of north‐western Australia. We used data from GPS‐based radiotelemetry (n = 49 lizards, tracked for 2–121 days, total n = 61 640 locations) to examine the size, internal structure and overlap of lizard home ranges. Despite substantial habitat differences at our two study sites (semi‐arid and relatively pristine habitat at Keep River National Park, Northern Territory, vs. highly disturbed and fragmented flood plain habitat in an agricultural area near Kununurra, Western Australia), home ranges were similar between the two areas, and between the two species. Our radio‐tracked lizards continued to disperse into previously unused areas throughout the duration of the study, so that the total areas used by lizards continued to increase. Based on the minimum convex polygon method, total home ranges averaged 4 ha (range 2–12 ha), but only about two‐thirds of each home range was used intensively. Each home range had multiple core areas, and overlap of core as well as peripheral areas (especially with same‐sex conspecifics) was high at the disturbed (Western Australia) site where lizard densities were high. The concentration of lizard activity within small core areas, often used by multiple individuals, suggests that these heavily used sites are critical to lizard conservation. However, the lizards' infrequent long‐distance displacements also make them vulnerable to changes in the wider landscape mosaic. Because GPS‐based radiotelemetry can quantify habitat use at finer spatial and temporal scales than earlier technologies, it can provide a robust base for management of at‐risk fauna. 相似文献
7.
8.
Shiny Cowbirds Molothrus bonariensis and Screaming Cowbirds Molothrus rufoaxillaris are closely related brood parasites but the former is socially polygynous or promiscuous and an extreme host generalist, whereas the latter is socially monogamous and parasitizes almost exclusively one host. Females of both species lay in relative darkness, before dawn, relying for host nest location on previous days’ prospecting activity, or possibly on following better‐informed roost associates. We studied the temporal and spatial patterns of roosting behaviour in these species to test the hypothesis that roosting behaviour of cowbirds is related to their breeding strategy (brood parasitism) and reflects differences in strategies between species. We recorded fidelity to a roost, location fidelity within a roost, inter‐individual spatial associations and timing of roost departures and parasitic events, using tagged individuals. Female Shiny Cowbirds and both sexes of Screaming Cowbirds showed marked fidelity in roosting location, and roost departures occurred both during and after the known time window for parasitism, with earlier departures probably corresponding to laying days. Screaming Cowbird females and males that were trapped together and showed high levels of association during the day, also showed high levels of association in the roost. We describe the spatial and temporal patterns of a relatively poorly known aspect of avian ecology in general and the behaviour of brood parasites in particular. 相似文献
9.
Seed dispersal by rodents has been understudied in Africa. Based on seed‐removal experiments, the presence of seeds in burrows and caches, cotyledon burial of seedlings, and images from camera traps, we provide evidence that rodents (Cricetomys kivuensis) remove and hoard large seeds of Carapa grandiflora in Nyungwe National Park, Rwanda. 相似文献
10.
Vincent N. Naude Guy A. Balme Justin O'Riain Luke T.B. Hunter Julien Fattebert Tristan Dickerson Jacqueline M. Bishop 《Ecology and evolution》2020,10(8):3605-3619
Anthropogenic mortality of wildlife is typically inferred from measures of the absolute decline in population numbers. However, increasing evidence suggests that indirect demographic effects including changes to the age, sex, and social structure of populations, as well as the behavior of survivors, can profoundly impact population health and viability. Specifically, anthropogenic mortality of wildlife (especially when unsustainable) and fragmentation of the spatial distribution of individuals (home‐ranges) could disrupt natal dispersal mechanisms, with long‐term consequences to genetic structure, by compromising outbreeding behavior and gene flow. We investigate this threat in African leopards (Panthera pardus pardus), a polygynous felid with male‐biased natal dispersal. Using a combination of spatial (home‐range) and genetic (21 polymorphic microsatellites) data from 142 adult leopards, we contrast the structure of two South African populations with markedly different histories of anthropogenically linked mortality. Home‐range overlap, parentage assignment, and spatio‐genetic autocorrelation together show that historical exploitation of leopards in a recovering protected area has disrupted and reduced subadult male dispersal, thereby facilitating opportunistic male natal philopatry, with sons establishing territories closer to their mothers and sisters. The resultant kin‐clustering in males of this historically exploited population is comparable to that of females in a well‐protected reserve and has ultimately led to localized inbreeding. Our findings demonstrate novel evidence directly linking unsustainable anthropogenic mortality to inbreeding through disrupted dispersal in a large, solitary felid and expose the genetic consequences underlying this behavioral change. We therefore emphasize the importance of managing and mitigating the effects of unsustainable exploitation on local populations and increasing habitat fragmentation between contiguous protected areas by promoting in situ recovery and providing corridors of suitable habitat that maintain genetic connectivity. 相似文献
11.
Ryan C. Burner Sundev Gombobaatar Paul van Els Lindsay R. Burner Dorj Usukhjargal Myagmar Bayasgalantselmeg 《Journal of Field Ornithology》2019,90(3):266-276
Amur Falcons (Falco amurensis) are a migratory species that face a variety of threats across their range, but little is known about their breeding ecology. These falcons breed in forest habitats in Eastern and Central Asia using nests constructed by corvids, including Eurasian Magpies (Pica pica). We monitored nests of 21 pairs of Amur Falcons at Hustai National Park in central Mongolia in 2017. Our objectives were to describe their basic nesting ecology, estimate nest survival by modeling the daily survival rate (DSR), examine nest selection by modeling it as a function of nest and site covariates, and use a spatial simulation to test hypotheses concerning intra‐ and interspecific avoidance. Clutch sizes averaged 4.1 eggs (N = 21 nests), and incubation and nestling periods averaged 25.7 and 26.1 d, respectively. The daily survival rate was 0.98, with young in 12 nests surviving to fledging. Nest structures were more likely to be selected as percent cover of nest bowls increased, usually in the form of a dome of sticks with multiple side entrances. Closed nests likely provide increased protection from predators. In contrast to congeneric Red‐footed Falcons (F. vespertinus) that nest in large colonies, Amur Falcons nested no farther from or closer to nests of either conspecifics or congeners than expected by chance. One factor likely contributing to this difference is that Red‐footed Falcons often use the nests of colonial‐nesting Rooks (Corvus frugilegus), whereas Amur Falcons typically use the nests of non‐colonial Eurasian Magpies. The ongoing loss of deciduous trees like white birch (Betula platyphylla) across the breeding range of Amur Falcons, probably due to climate change and increased grazing pressure, is likely to reduce the availability of nesting habitat for Eurasian Magpies which, in turn, will likely reduce availability of nests for Amur Falcons and other small falcons. 相似文献
12.
The restricted area of space used by most mobile animals is thought to result from fitness‐rewarding decisions derived from gaining information about the environment. Yet, assessments of how animals deal with uncertainty using memory have been largely theoretical, and an empirically derived mechanism explaining restricted space use in animals is still lacking. Using a patch‐to‐patch movement analysis, we investigated predictions of how free‐ranging bison (Bison bison) living in a meadow‐forest matrix use memory to reduce uncertainty in energy intake rate. Results indicate that bison remembered pertinent information about location and quality of meadows, and they used this information to selectively move to meadows of higher profitability. Moreover, bison chose profitable meadows they had previously visited, and this choice was stronger after visiting a relatively poor quality meadow. Our work demonstrates a link between memory, energy gains and restricted space use while establishing a fitness‐based integration of movement, cognitive and spatial ecology. 相似文献
13.
Donna J. Shaver Kristen M. Hart Ikuko Fujisaki Cynthia Rubio Autumn R. Sartain Jaime Peña Patrick M. Burchfield Daniel Gomez Gamez Jaime Ortiz 《Ecology and evolution》2013,3(7):2002-2012
For many marine species, locations of key foraging areas are not well defined. We used satellite telemetry and switching state‐space modeling (SSM) to identify distinct foraging areas used by Kemp's ridley turtles (Lepidochelys kempii) tagged after nesting during 1998–2011 at Padre Island National Seashore, Texas, USA (PAIS; N = 22), and Rancho Nuevo, Tamaulipas, Mexico (RN; N = 9). Overall, turtles traveled a mean distance of 793.1 km (±347.8 SD) to foraging sites, where 24 of 31 turtles showed foraging area fidelity (FAF) over time (N = 22 in USA, N = 2 in Mexico). Multiple turtles foraged along their migratory route, prior to arrival at their “final” foraging sites. We identified new foraging “hotspots” where adult female Kemp's ridley turtles spent 44% of their time during tracking (i.e., 2641/6009 tracking days in foraging mode). Nearshore Gulf of Mexico waters served as foraging habitat for all turtles tracked in this study; final foraging sites were located in water <68 m deep and a mean distance of 33.2 km (±25.3 SD) from the nearest mainland coast. Distance to release site, distance to mainland shore, annual mean sea surface temperature, bathymetry, and net primary production were significant predictors of sites where turtles spent large numbers of days in foraging mode. Spatial similarity of particular foraging sites selected by different turtles over the 13‐year tracking period indicates that these areas represent critical foraging habitat, particularly in waters off Louisiana. Furthermore, the wide distribution of foraging sites indicates that a foraging corridor exists for Kemp's ridleys in the Gulf. Our results highlight the need for further study of environmental and bathymetric components of foraging sites and prey resources contained therein, as well as international cooperation to protect essential at‐sea foraging habitats for this imperiled species. 相似文献
14.
We investigated sex‐related site fidelity by humpback whales to the Fueguian Archipelago, a new feeding area in the eastern South Pacific, by examining the resighting histories of 45 males and 39 females recorded from 2003 to 2012. Results indicated an overall annual return to the feeding area of 74.8%, and annual sex ratio is roughly equal in the population. The probability of an individual being resighted across years and in subsequent years was not significantly different for both males and females, however, the proportion of resighting within a year was significantly higher for individual males compared to females. Potential sources of sex‐related bias were analyzed, but none were found to be significant. Greater intraannual resighting frequency for males may reflect sex‐based differences in spatial occupation and short‐range movements due to potential differences in energy budgets. 相似文献
15.
Sabina Burrascano Francesco Ripullone Liliana Bernardo Marco Borghetti Emanuela Carli Michele Colangelo Carmen Gangale Domenico Gargano Tiziana Gentilesca Giuseppe Luzzi Nicodemo Passalacqua Luca Pelle Anna Rita Rivelli Francesco Maria Sabatini Aldo Schettino Antonino Siclari Dimitar Uzunov Carlo Blasi 《植被学杂志》2018,29(1):98-109
Questions
Do vascular plant species richness and beta‐diversity differ between managed and structurally complex unmanaged stands? To what extent do species richness and beta‐diversity relate to forest structural attributes and heterogeneity?Location
Five national parks in central and southern Italy.Methods
We sampled vascular plant species composition and forest structural attributes in eight unmanaged temperate mesic forest stands dominated or co‐dominated by beech, and in eight comparison stands managed as high forests with similar environmental features. We compared plant species richness, composition and beta‐diversity across pairs of stands (unmanaged vs managed) using GLMM s. Beta‐diversity was quantified both at the scale of each pair of stands using plot‐to‐plot dissimilarity matrices (species turnover), and across the whole data set, considering the distance in the multivariate species space of individual plots from their centroid within the same stand (compositional heterogeneity). We modelled the relationship between species diversity (richness and beta‐diversity) and forest structural heterogeneity and individual structural variables using GLMM s and multiple regression on distance matrices.Results
Species composition differed significantly between managed and unmanaged stands, but not richness and beta‐diversity. We found weak evidence that plant species richness increased with increasing levels of structural heterogeneity and canopy diversification. At the scale of individual stands, species turnover was explained by different variables in distinct stands, with variables related to deadwood quantity and quality being selected most often. We did not find support for the hypothesis that compositional heterogeneity varies as a function of forest structural characteristics at the scale of the whole data set.Conclusions
Structurally complex unmanaged stands have a distinct herb layer species composition from that of mature stands in similar environmental conditions. Nevertheless, we did not find significantly higher levels of vascular plant species richness and beta‐diversity in unmanaged stands. Beta‐diversity was related to patterns of deadwood accumulation, while for species richness the evidence that it increases with increasing levels of canopy diversification was weak. These results suggest that emulating natural disturbance, and favouring deadwood accumulation and canopy diversification may benefit some, but not all, facets of plant species diversity in Apennine beech forests.16.
Jan F. Kamler Melissa M. Gray Annie Oh David W. Macdonald 《Ecology and evolution》2013,3(9):2892-2902
We incorporated radio‐telemetry data with genetic analysis of bat‐eared foxes (Otocyon megalotis) from individuals in 32 different groups to examine relatedness and spatial organization in two populations in South Africa that differed in density, home‐range sizes, and group sizes. Kin clustering occurred only for female dyads in the high‐density population. Relatedness was negatively correlated with distance only for female dyads in the high‐density population, and for male and mixed‐sex dyads in the low‐density population. Home‐range overlap of neighboring female dyads was significantly greater in the high compared to low‐density population, whereas overlap within other dyads was similar between populations. Amount of home‐range overlap between neighbors was positively correlated with genetic relatedness for all dyad‐site combinations, except for female and male dyads in the low‐density population. Foxes from all age and sex classes dispersed, although females (mostly adults) dispersed farther than males. Yearlings dispersed later in the high‐density population, and overall exhibited a male‐biased dispersal pattern. Our results indicated that genetic structure within populations of bat‐eared foxes was sex‐biased, and was interrelated to density and group sizes, as well as sex‐biases in philopatry and dispersal distances. We conclude that a combination of male‐biased dispersal rates, adult dispersals, and sex‐biased dispersal distances likely helped to facilitate inbreeding avoidance in this evolutionarily unique species of Canidae. 相似文献
17.
When group members possess differing information about the environment, they may disagree on the best movement decision. Such conflicts result in group break‐ups, and are therefore a fundamental driver of fusion–fission group dynamics. Yet, a paucity of empirical work hampers our understanding of how adaptive evolution has shaped plasticity in collective behaviours that promote and maintain fusion–fission dynamics. Using movement data from GPS‐collared bison, we found that individuals constantly associated with other animals possessing different spatial knowledge, and both personal and conspecific information influenced an individual's patch choice decisions. During conflict situations, bison used group familiarity coupled with their knowledge of local foraging options and recently sampled resource quality when deciding to follow or leave a group – a tactic that led to energy‐rewarding movements. Natural selection has shaped collective behaviours for coping with social conflicts and resource heterogeneity, which maintain fusion–fission dynamics and play an essential role in animal distribution. 相似文献
18.
Julia Staggenborg H. Martin Schaefer Christian Stange Beat Naef‐Daenzer Martin U. Grüebler 《Ibis》2017,159(3):519-531
In many bird species, parents adjust their home‐ranges during chick‐rearing to the availability and distribution of food resources, balancing the benefits of energy intake against the costs of travelling. Over recent decades, European agricultural landscapes have changed radically, resulting in the degradation of habitats and reductions in food resources for farmland birds. Lower foraging success and longer foraging trip distances that result from these changes are often assumed to reduce the reproductive performance of parents, although the mechanisms are not well understood. We tested the behavioural response of chick‐rearing Little Owls Athene noctua to variation in habitat diversity in an agricultural landscape. We equipped females with GPS loggers and received adequate range‐use data for 19 individuals (6063–14 439 locations per bird). In habitats dominated by homogeneous cropland habitats, home‐ranges were over 12 ha in size, whereas in highly diverse habitats they were below 2 ha. Large home‐ranges were associated with increased flight activity (117% of that of birds in small home‐ranges) and distances travelled per night (152%), increased duration of foraging trips (169%) covering larger distances (246%), and reduced nest visiting rates (81%). The study therefore provides strong correlative evidence that Little Owls breeding in monotonous farmland habitats expend more time and energy for a lower benefit in terms of feeding rates than do birds in more heterogeneous landscapes. As nestling food supply is the main determinant of chick survival, these results suggest a strong impact of farmland characteristics on local demographic rates. We suggest that preserving and creating islands of high habitat diversity within uniform open agricultural landscapes should be a key target in the conservation of Little Owl populations. 相似文献
19.
Shade coffee plantations are considered important habitats for frugivorous bats. However, it is not known if bats use this agricultural habitat for shelter, food resources, or both. This study addresses these questions using the highland yellow‐shouldered bat (Sturnira hondurensis) as an example. Twenty‐six adult individuals of S. hondurensis were captured, 50 percent in tropical montane cloud forest (TMCF) and 50 percent in shade coffee plantations (SCP) in Veracruz, Mexico, and each was fitted with a radio transmitter for locating roosts and feeding areas. Data were obtained from 24 of them. The fieldwork was conducted between October 2010 and October 2011 covering all seasons. Twenty‐two day roosts were located in the cavities of twelve different species of tree. Roosts located in TMCF differed significantly from those in SCP, having a smaller crown area and a greater species richness and density of plants around the roost. In SCP, both the average home range and the average core use area were smaller than in TMCF, but the differences were not statistically significant. Distances travelled by bats were generally longer and more variable in the SCP; the distance between capture site and foraging site was significantly greater in SCP than in TMCF. In SCP, there were fewer understory chiropterochorous plants, which are the main item in the diet of this bat and many other sympatric species of frugivorous bats. Although S. hondurensis does use roosts and foraging sites in the SCP, it is important to note that this species and others with similar requirements primarily depend on the preservation of intact forest adjacent to modified landscapes, where roosts and fruit are constantly available in abundance. Management practices should guarantee a greater density and diverse of trees and the preservation of understory plants with fruits in the coffee plantations that allow a long‐term survival of frugivorous bats populations. 相似文献
20.