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Settlement Ecology: The Social and Spatial Organization of Kofyar Agriculture. Glenn Davis Stone. Tucson: University of Arizona Press, 1996. 256 pp.  相似文献   

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Ecology and Evolution of Social Organization in Arctic Sandpipers   总被引:1,自引:0,他引:1  
A comparative analysis of sandpiper social systems on arcticand subarctic breeding grounds (24 species in the family Scolopacidae,subfamily Calidridinae) shows four major patterns. In a majorityof the species (15), populations are dispersed through a stronglydeveloped territorial system, with strong monogamous pair bondsand only minor yearly fluctuations in numbers. The second patternis seen in three species in which the female of a pair may laytwo sets of eggs in quick succession, one for each member ofthe pair to incubate. This opens opportunities for facultativepolygyny or polyandry (‘serial polygamy’) and forthe evolutionary weakening of the strong pair bond seen in thefirst pattern. The third and fourth patterns are those of polygyny(three species) and promiscuity (three species). These six speciesshow clumped dispersions; their year-to-year fluctuations tendto be strong; the males defend compressible, often small, territories;and high densities can occur locally. It is suggested that thepattern of overdispersion and monogamy represents a conservativemode of adapting to high-latitude environments, while the patternof clumped dispersion with polygyny or promiscuity representsan opportunistic mode in that the birds are concentrated intobreeding areas where and when weather, food, and/or some otherenvironmental factors are particularly favorable. Apparentlyfalling evolutionarily between these two basic patterns areseveral species conservative in their life-styles, but polygamousat least occasionally and showing some features of opportunism.There is thus a striking diversity of social systems in calidridinesandpipers, that is, in the styles of habitat exploitation theyhave evolved in the arctic and subarctic habitats to which theirbreeding is confined. A graphic model suggesting paths of evolutionarydevelopment and of interplay among factors considered criticalin the evolution of these systems is proposed.  相似文献   

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Space availability is essential to grant the welfare of animals. To determine the effect of space availability on movement and space use in pregnant ewes (Ovis aries), 54 individuals were studied during the last 11 weeks of gestation. Three treatments were tested (1, 2, and 3 m2/ewe; 6 ewes/group). Ewes'' positions were collected for 15 minutes using continuous scan samplings two days/week. Total and net distance, net/total distance ratio, maximum and minimum step length, movement activity, angular dispersion, nearest, furthest and mean neighbour distance, peripheral location ratio, and corrected peripheral location ratio were calculated. Restriction in space availability resulted in smaller total travelled distance, net to total distance ratio, maximum step length, and angular dispersion but higher movement activity at 1 m2/ewe as compared to 2 and 3 m2/ewe (P<0.01). On the other hand, nearest and furthest neighbour distances increased from 1 to 3 m2/ewe (P<0.001). Largest total distance, maximum and minimum step length, and movement activity, as well as lowest net/total distance ratio and angular dispersion were observed during the first weeks (P<0.05) while inter-individual distances increased through gestation. Results indicate that movement patterns and space use in ewes were clearly restricted by limitations of space availability to 1 m2/ewe. This reflected in shorter, more sinuous trajectories composed of shorter steps, lower inter-individual distances and higher movement activity potentially linked with higher restlessness levels. On the contrary, differences between 2 and 3 m2/ewe, for most variables indicate that increasing space availability from 2 to 3 m2/ewe would appear to have limited benefits, reflected mostly in a further increment in the inter-individual distances among group members. No major variations in spatial requirements were detected through gestation, except for slight increments in inter-individual distances and an initial adaptation period, with ewes being restless and highly motivated to explore their new environment.  相似文献   

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A comparative and longitudinal ecological analysis is used to explore agricultural sources of variation in child nutritional status in the Taita Hills, Kenya. National policies, formal institutions, the natural environment, and the local-level social organization of agricultural resource access define the agrarian context within which distinct production strategies emerge. The effects of alternative production choices on child nutrition are neither consistent nor unidimensional, arguing for a rethinking of conventional approaches to food policy decision making.  相似文献   

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空间利用是野生动物对环境资源的利用模式和活动格局,影响着种群之间的基因交流和生存发展。我们于2010~2012年在四川卧龙国家级自然保护区的“核桃坪”及其附近区域,采用GPS颈圈跟踪技术对分布和放养于该区域的野生大熊猫和放牧家畜—马群进行了定位监测和样地调查。分别选择了3只大熊猫和3个马群的代表性个体的GPS颈圈数据,在地理信息系统(GIS)中通过数字高程模型(DEM)、动物移动模块等工具提取和计算了它们活动区域的地形地势、巢域大小、日移动距离和核域数量,并检验了野生大熊猫和放牧家畜空间利用的差异性。结果表明:野生大熊猫和放牧家畜不同月份和整体之间在海拔高度、坡度坡向、巢域面积、日移动距离和核域数量等方面都具有显著性的差异。野生大熊猫表现为随季节和食物类型(竹笋、竹秆、枝叶)丰度的变化分别活动于拐棍竹林、短锥玉山竹林和冷箭竹林中,活动空间较大(海拔范围、巢域大小)、日移动距离较短和核域数量多等特征的随机扩散模式,且不同个体和月份之间波动性较大;放牧家畜则因初始放养于不同区域的竹林(拐棍竹林、冷箭竹林)和人为干涉程度的大小差异,显示出不同的空间利用格局,但与大熊猫相比,总体而言都具有巢域面积小、日移动距离略大、核域数量极少等“步步为营”空间利用模式的特征,且不同畜群和不同时间之间的变化幅度也小于大熊猫。不同的空间利用格局对环境资源的影响强度截然不同,大熊猫的利用模式有利于竹子资源的更新恢复和生境结构的持续发展,而放牧家畜的利用模式将造成竹子资源的死亡衰败和生境结构的破坏退化。因此,加强放牧家畜的管控,有效协调社区经济发展和生物多样性保护成为卧龙自然保护区(特区)今后工作和管理的当务之急。  相似文献   

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Der Klippspringer (Oreotragus oreotragus) wurde in drei Gebieten in Athiopien beobachtet. Meist leben ein ♂ und ein bis zwei ♀♀ zusammen. Die Gruppe hat ein kleines Wohngebiet (etwa 8 ha), das sie gegen andere Gruppen verteidigt. Klippspringer fressen meist Gras und Blätter von Büschen. Klippspringer haben viele Feinde. Das ♂ steht meist Wache, während das ♀ gesichert frißt. Das ♀ führt Ortswechsel an. Die Jungen werden nach der Regenzeit im November geboren. Im folgenden Jahr verlassen die männlichen Jungen ihre elterliche Gruppe; die weiblichen Jungen bleiben länger darin, und einige paaren sich mit ihrem Vater. Stabile Paarbindungen werden als Anpassung an offene Landschaft gedeutet; das ♂ kann ♀♀ und Junge beschiitzen.  相似文献   

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ABSTRACT. Planktonic sarcodines, suspended in the water column, are conveniently grouped into three categories based on functional morphology: (1) gymnamoebae and their relatives, which lack major living or nonliving compartmentalizing barriers, (2) foraminifera, and testate amoebae enclosed by a test or shell with one or more major openings, but lacking extensive cytoplasmic compartmentalizing barriers, and (3) radiolaria, which exhibit distinct compartmentalization of the cytoplasm into functional zones. Differences in feeding strategies and trophic activity of members in the three groups reflect in part these differences in functional morphology. Members of all three groups form symbiotic associations with Monera and protists, including algae, thus partially offsetting interspecific trophic competition among species occupying the same water mass. Physiological and morphological adaptations supporting a symbiotic association are presented. C14-labeling studies of endosymbiotic radiolarian species show a substantial contribution of carbon to the host. Rates of calcification (planktonic foraminfera) and silica deposition (radiolaria) are reported, based on morphometric analyses and isotopic labeling studies. Major distributional patterns in space and time for each of the three groups, and some ecological principles explaining these regularities, are presented as related to population growth dynamics, niche differentiation, water-mass properties, and the role of symbionts in supporting highly diverse communities of species within the same locale in the water column.  相似文献   

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Approximately 45 species of kangaroos and their smaller relativesoccupy virtually every terrestrial habitat in Australia. Themost social macropod is the whiptail wallaby, which lives inpermanent, discrete mobs of up to 50 individuals of mixed ageand sex. Group formation is facilitated by their grazing habits,open forest and pasture habitat, partly diurnal activity, andlow level of intraspecific aggressiveness. Pressure from cursorialpredators, plus the whiptail's non-seasonal breeding and briefestrus, make group living adaptive. Ancestral macropods arebelieved to have been rabbit-sized inhabitants of dense forest,omnivorous, nocturnal, and essentially solitary. The major evolutionarytrends in the family have been toward larger size and grazinghabits; the trends toward diurnality and group living have hadmore modest results. Progressive stages in macropod social evolutionmay be represented by the present-day musk rat-kangaroo, thequokka, and the whiptail wallaby.  相似文献   

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Abstract: Remote cameras are an increasingly important tool in management and wildlife studies. However, we often do not know if they provide an unbiased sample of populations. Using a marked, radiocollared population of coyotes (Canis latrans) of known social status, we evaluated the influence of temporal (daily and seasonal) and spatial (distance between units, habitat, and proximity to human structures) factors on vulnerability to photo-captures. During 8 unbaited camera sessions of 6 weeks each, we obtained 158 coyote photographs at a photo-capture success rate of 1.6%. We were able to identify not only marked individuals, but also a number of uncollared adults through variation in their pelage. Photo-capture of adults peaked 2 weeks after we established camera stations. Annual success for photographing adult coyotes was greatest during March and April, which corresponded with the dispersal season. The majority of photo-captures occurred at night, and adult photo-captures peaked around midnight, with smaller peaks at dawn and dusk. Rather than reflecting a circadian activity pattern, nighttime captures seemed to reflect when adult coyotes were most vulnerable to photo-capture. Characteristics of camera locations, such as amount of human activity, being on roads versus trails, and habitat type, also influenced the number of photo-captures. We conclude that remote cameras do not always provide an unbiased sample of populations and that animal behavior is important to consider when using these systems. Researchers using camera techniques need to carefully consider when, where, and how cameras are placed to reduce this bias.  相似文献   

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Biological control can be considered an intentional induction of a trophic cascade, whereby the addition of herbivores’ natural enemies or other habitat manipulations effectively enhance natural enemy populations, lead to reduced herbivore populations or feeding damage, and indirectly improve or protect plant health, agricultural yield, or the condition of some other biotic population or community of interest to man. The following set of papers (Denno et al., 2008; Ram et al., 2008; Stuart and Duncan, 2008; Spence et al. 2008) offer insights into the broad- and fine-scale factors that ultimately contribute to the success of biological control efforts. Many of the ideas herein were presented and discussed during a special session at the 2007 Annual Meeting of the Society of Nematologists. The goal of this session was to examine explicitly the ramifications of spatial and temporal heterogeneity in the context of effective biological control. The biological focus was primarily on interactions involving entomopathogenic nematodes (EPN), although many of the authors’ conclusions are applicable to other types of nematodes, soil fauna and natural enemies in general.  相似文献   

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Primate Behavioral Ecology: From Ethnography to Ethology and Back   总被引:1,自引:0,他引:1  
Nonhuman primates occupy a special niche in anthropology because of the comparative insights into humans they provide. Initial anthropological interest in primates targeted the apes for their close phylogenetic relationships with humans, and the semiterrestrial Old World monkeys for their ecological similarities with hominids adapting to life on the ground. From the earliest anecdotal reports of tool use and hunting to more contemporary quantitative analyses of local "cultural" traditions, nonhuman primates have challenged deep-rooted concepts of human uniqueness and redefined the boundaries between us and other animals. Yet, despite the long-standing influence of primate studies in anthropology, approaches to studying primates began diverging from those of earlier ethnographers. Advances in primatology, particularly during the 1990s, have included a much deeper understanding of how ecology, phylogeny, and demography affect behavior. Insights into intraspecific, population-level variation represent an important area of convergence between primatology, other areas of anthropology, and conservation biology. [Keywords: primate behavioral ecology, anthropocentrism, evolutionary theory, systematic methods, biology]  相似文献   

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Governments and non-govermental organizations (NGOs) that plan projects to conserve the environment and alleviate poverty often attempt to modify rural livelihoods by halting activities they judge to be destructive or inefficient and encouraging alternatives. Project planners typically do so without understanding how rural people themselves judge the value of their activities. When the alternatives planners recommend do not replace the value of banned activities, alternatives are unlikely to be adopted, and local people will refuse to participate. Human behavioral ecology and behavioral economics may provide useful tools for generating and evaluating hypotheses for how people value economic activities in their portfolios and potential alternatives. This is demonstrated with a case example from southwestern Madagascar, where plans to create a Mikea Forest National Park began with the elimination of slash-and-burn maize agriculture and the encouragement to plant labor-intensive manioc instead. Future park plans could restrict access to wild tuber patches, hunting small game, and fishing. The value of these activities is considered using observational data informed by optimal foraging theory, and experimental data describing people’s time preference and covariation perception. Analyses suggest that manioc is not a suitable replacement for maize for many Mikea because the two crops differ in terms of labor requirements, delay-to-reward, and covariation with rainfall. Park planners should promote wild tuber foraging and stewardship of tuber patches and the anthropogenic landscapes in which they are found. To conserve small game, planners must provide alternative sources of protein and cash. Little effort should be spent protecting lemurs, as they are rarely eaten and never sold.  相似文献   

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