白枕鹤的领域防御行为

1986—1988年,作者就白枕鹤(Grus vipio)的领域防御行为在黑龙江省扎龙自然保护区进行初步调查。 每年4月中旬,营巢期间白枕鹤的巢区限界已经十分明显,巢区面积不超过10平方公里,多在常年积水的芦苇沼泽之中,其间均有小片耕地作为主要采食地。 除直接观察外,我们按白枕鹤对入侵者的反应程度不同,划分为5个不同等级:无明显反应(R_0);振翅鸣叫(R_1);起飞逼近入侵者(R_2):将入侵者逐出巢区(R_3);啄斗(R_4)。试图以定量的方法研究领域鹤对入侵者的反应。     

鄱阳湖越冬白枕鹤活动区面积与水位和气温的关系

2014年11月至2015年3月,以及2015年11月至2016年3月,利用卫星跟踪技术对6只越冬于鄱阳湖的白枕鹤(Grus vipio)活动区面积进行了研究,利用广义线性混合模型(GLMM)分析了水位、气温、年份、年龄及个体差异对活动区面积的影响,利用Pearson相关分析将对活动区面积影响较大的因子与活动区面积进行了相关性分析。结果发现,两个越冬期内白枕鹤平均周活动区面积,2014至2015越冬期为(57.85±94.67)km~2,2015至2016越冬期为(12.01±17.74)km~2。在两个越冬期内,活动区面积均呈显著下降趋势(2014~2015年,t=﹣2.831,P0.01;2015~2016年,t=﹣3.422,P0.01);气温对活动区面积的影响不显著(P0.05),而水位对活动区面积具有极显著影响(P0.01);2014~2015年水位高度(14.92±0.65)m,2015~2016年水位高度(15.39±0.70)m,周活动区面积与同期水位高度显著正相关(2014~2015年,r=0.370,P0.01;2015~2016年,r=0.380,P0.01)。推测水位的变化影响越冬白枕鹤主要食物的生长及可获得性,进而导致越冬期白枕鹤活动区面积的相应变化。     

浙江省新近耕地动态及其驱动因素

利用RS和GIS技术对2000、2005和2008年遥感影像数据进行人机交互解译,建立了2000-2008年浙江省耕地动态数据库,并运用岭回归分析法研究了耕地变化的驱动力及其特征.结果表明：2000-2008年间,浙江省耕地变化较剧烈,2000-2005、2005-2008年,研究区耕地年动态度分别为-1.42%和-1.46%,耕地主要流向城乡工矿居民用地.非农人口比例、房地产开发投资、城市绿化面积和果园面积构成了浙江省乃至我国东部发达地区耕地变化的主要驱动因素.     

丹顶鹤与白枕鹤的领域比较研究

丹顶鹤与白枕鹤的领域比较研究ＡＣＯＭＰＡＲＡＴＩＶＥＳＴＵＤＹＯＮＴＥＲＲＩＴＯＲＩＥＳＯＦＷＨＩＴＥＮＡＰＥＤＣＲＡＮＥＡＮＤＲＥＤＣＯＲＯＷＮＥＤＣＲＡＮＥ关键词丹顶鹤白枕鹤领域ＫｅｙｗｏｒｄｓＲｅｄｃｒｏｗｎｅｄｃｒａｎｅ,Ｗｈｉｔｅｎ...     

扎龙国家级自然保护区冬季笼养丹顶鹤与白枕鹤种间适合度的比较

通过比较黑龙江扎龙国家级自然保护区冬季笼养丹顶鹤Grus japonensis与白枕鹤Grus vipio的适合度,以期为拟定不同的保护对策提供参考。本文以保护区冬季1月(4周)单笼饲养的丹顶鹤(5♀、7♂)和白枕鹤(3♀、5♂)为研究对象,对其体质量变化、摄食量和摄食比例、摄入能量需求及能量收支进行种间比较。结果发现,丹顶鹤的体质量下降(9.35%)显著而白枕鹤体质量下降(3.02%)不显著。丹顶鹤和白枕鹤的摄食比例(鲫鱼/玉米)分别为12.70/1和0.93/1。丹顶鹤摄入能量和排出水热能散失实测值均极显著高于白枕鹤(P0.001)。丹顶鹤与白枕鹤单位体质量(/kg)能量收支比较,摄入能量种间差异无统计学意义(P0.05),而丹顶鹤的排出水热能散失极显著高于白枕鹤(P0.01)。另外,低温和短光照的胁迫使可摄食鲫鱼和玉米的时间分别在5.5 h和9.5 h以内。结果表明,冬季相同生境中丹顶鹤和白枕鹤的摄入能量需求水平相同,但其能量收支因摄食偏好而出现显著变化。总之,从食性偏好、食物可获得性和能量收支来看,保护区冬季笼养白枕鹤的适合度应该高于丹顶鹤。     

基于土地利用/覆被变化的荒漠绿洲碳储量动态评估

以典型的荒漠绿洲区为研究对象,基于不同时期土地利用/覆被类型图,运用Bookkeeping模型,结合土壤、植被碳密度基础资料及调查数据,评估了近30年临泽绿洲土地利用/覆被变化特征及其对碳储量的影响。结果表明:(1)临泽荒漠绿洲区的土地利用/覆被变化特征主要表现为:居民及建设用地、耕地、林地呈增加趋势,增幅分别为90.2%、75%、46.5%;盐碱地、水体、沙地、荒漠草地则呈减少趋势,减幅分别为73.9%、67.8%、46.2%、5.5%。(2) 30 a耕地面积增加了269.38 km~2,其中耕地开垦面积为372.57 km~2,开垦主要来源于盐碱地、荒漠草地和沙地,分别占耕地开垦面积的24.7%、24.4%和21.05%。耕地转变为其他土地覆被类型的面积为103.19 km~2,转变后的主要去向分别是居民及建设用地、盐碱地和荒漠草地,分别占耕地转变为其他土地覆被类型面积的32.78%、17.8%和15.37%。(3)土地利用/覆被变化导致总碳储量增加5.89×10~5t,其中土壤碳储量增加量为4.02×10~5t,植被碳储量增加量为1.86×10~5t;耕地变化使碳储量增加4.91×10~5t,其中使碳储量增加的转变分别是荒漠草地-耕地、沙地-耕地、盐碱地-耕地、耕地-林地,相反的转变则使碳储量减少。总体来看,临泽荒漠绿洲土地利用/覆被面积和结构均发生了变化,耕地开垦为最主要的土地利用/覆被变化,土地利用/覆被变化导致碳储量总体呈增加趋势,耕地变化是影响碳储量变化的主要因素。     

黑龙江扎龙自然保护区白枕鹤巢址选择特征

为了探讨白枕鹤Grusvipio的巢址选择特征,2007～2009年的4～5月,在黑龙江省扎龙自然保护区采用定点观察法、样方调查法、因子调查法和因子分析及显著性检验等,对白枕鹤的营巢生境类型和营巢生境特征进行了调查。结果表明,白枕鹤对营巢生境类型的要求比较单一,仅选择芦苇沼泽;巢址生境特征具有明显的偏好,即(1)距干扰区的距离多在1.5km以上(86.36%),(2)巢周的水深多小于16cm(95.45%),(3)巢周明水面面积多小于200m2(90.90%),(4)巢距火烧地的距离以1.0～2.5km居多(63.64%),(5)剩余苇丛面积多小于200m2(86.37%)、距剩余苇丛距离多大于30m(81.82%)、剩余苇丛密度多小于500株/m2(77.27%)、剩余苇丛高度以大于1.5m的居多(72.73%)。进一步分析表明,白枕鹤对营巢生境特征的要求具有普遍性和特殊性,表现出一定的适应能力,火烧地、剩余苇丛、干扰区和水是其营巢的主要环境特征。     

从固原县的恶性循环看生态失调的危害性

固原县位于宁夏回族自治区南部,面积6,413.75平方公里,是黄土高原138个水土流失重点县之一。全县有37个公社,1个镇,413个大队,3,364个生产队。总人口55万,每平方公里平均80多人。现有农耕地419万亩,人均耕地8亩,每个劳动力负担24亩。林地316,000亩,     

岷江上游汶川县耕地景观变化及空间驱动力

基于遥感影像和地理信息系统技术,应用景观指数和Kappa指数系列方法对岷江上游耕地景观变化进行研究,并引入二项Logistic逐步回归模型,选择海拔、坡度、坡向、到道路、河流和居民点距离为驱动因子对汶川县耕地景观变化的空间驱动力进行分析.结果表明: 研究期间耕地景观面积一直处于增长趋势,1974—1986年间耕地景观面积增幅最大.1986—2000年间耕地面积增加不明显,但是耕地景观与其它景观类型相互转换频繁,空间位置变化剧烈,特别是1994—2000年期间.耕地景观面积变化的驱动力主要为政策变化.耕地景观变化的空间驱动力在不同时间段内存在较大差异.     

华北农田生态系统景观格局的演变特征

基于华北6 省(市)2000、2005、2010 年三期土地覆盖遥感数据, 通过计算农田景观格局指数和农田景观转移矩阵, 在省域范围的大空间尺度上分析了2000-2010 年农田生态系统景观格局的变化特征。结果表明, 2000 年至2010年华北6 省(市)的农田景观格局变化主要表现为: 耕地景观的面积在减少, 破碎化程度在加大, 斑块形状趋于简单化;园地景观的面积在增加, 破碎化程度在降低, 斑块形状趋于复杂化。耕地减少的面积主要转变为城镇, 增加的面积主要来自水体; 园地减少的面积主要转变为耕地, 增加的面积主要来自耕地, 园地景观主要与耕地景观相互转化。城镇化等人类活动加剧了耕地的减少和破碎化, 应加强耕地保护, 特别是耕地的集约化布局, 降低农田破碎化程度, 促进农田的可持续发展。     

丹顶鹤与白枕鹤的领域比较

有７种濒危鹤类受到现代人的威胁［２０］,丹顶鹤（Ｇｒｕｓｊａｐｏｎｅｎｓｉｓ）和白枕鹤（Ｇｒｕｓｖｉｐｉｏ）是其中两种,分别为我国的Ⅰ、Ⅱ级保护动物。在中国丹顶鹤主要在黑龙江省的乌裕尔河下游和三江平原等地繁殖,数量在４８２～５０２之间［７］。吉林省的向海也有４０余只繁殖鹤［８,９］。它们在长江中下游的江苏盐城、高邮湖、洪泽湖,安徽省的城东湖、石臼湖、菜子湖越冬［５］。白枕鹤繁殖区在中国东北的乌裕尔河下游、向海、达里诺尔湖以及乌苏里江以东俄罗斯的沿海边区［２０］。我国已知的繁殖区内数量不多［１］,…     

Causes and consequences of individual variation in territory size in the American red squirrel

For most territorial species that defend food or other resources, territory size is inversely related to resource density. However, in some food-based territorial species, larger territories are known to contain greater absolute resource availability. For these latter species, both the specific determinants of territory size, and the relationship between territory size and fitness, remain unclear. We predicted that in American red squirrels ( Tamiasciurus hudsonicus ), where larger territories tend to hold increased food resources, survival should be correlated positively with territory size and that both individual (body mass, sex, duration of territory ownership) and habitat-specific (population density) attributes would contribute to variation in territory size. We monitored survival and territory size of 58 squirrels during a two-year period using live-trapping and radio-telemetry. Survival and territory size were correlated positively, with each 0.1 ha decrease in territory size typically resulting in a 16.6% increase in mortality risk; mortality risk for squirrels with the smallest versus largest territories differed by up to 23-fold. Territory size was negatively related to local population density, but not to any attributes of individual squirrels, implying that, in this species, territory size may not be influenced strongly by individual quality. We conclude that while larger territories may confer a survival advantage to squirrels, territory size is unrelated to individual physical attributes, likely because costs associated with the acquisition of a larger or richer territory outweigh potential benefits of increased food access.     

Territory quality determines social group composition in Ethiopian wolves Canis simensis

1. We contrast the value of four different models to predict variation in territory size as follows: resource density (the ideal free distribution), population density, group size and intruder pressure (relative resource-holding potential). In the framework of the resource dispersion hypothesis, we test the effect of resource abundance and spatial variation in resource distribution on the age/sex composition of social groups. 2. We explore these drivers of territory size and group size/composition in Ethiopian wolves Canis simensis in the Bale Mountains, Ethiopia, using fine-scale distribution maps of their major prey species based on satellite-derived vegetation maps. 3. The number of adult males is correlated with territory size, while prey density, wolf population density and intruder pressure are not associated with territory size. On average, each additional adult male increases territory size by 1.18 km(2). 4. Prey abundance increases with territory size (average biomass accumulation of 6.5 kg km(-2)), and larger territories provide greater per capita access to prime foraging habitat and prey. 5. The age/sex composition of wolf packs is more closely related to territory quality than territory size. Subordinate adult females are more likely to be present in territories with greater proportions of prime giant molerat Tachyoryctes macrocephalus habitat (i.e. >80% of Web Valley territories and >20% in Sanetti/Morebawa), and more yearlings (aged 12-23 months) occur in territories with greater overall prey biomass. 6. Wolf packs with restricted access to good foraging habitat tend to defend more exclusive territories, having a lower degree of overlap with neighbouring packs. 7. The greater per capita access to prey in large groups suggests a strong evolutionary advantage of collaborative territorial defence in this species, although the relative costs of territorial expansion vs. exclusion depend upon the spatial distribution of resources. We propose a model whereby territory size is determined by the number of adult males, with the presence of subordinate females and yearlings dependent on the quality of habitat, and the abundance and distribution of prey, incorporated within territory boundaries.     

Determinants of territory size in the pomacentrid reef fish,Parma victoriae

Summary Factors governing the size of territories defended by the pomacentrid reef fish, Parma victoriae, were investigated, prompted by contradictory predictions in the literature concerning the effects of food supply and competitors. Observations were carried out over the non-breeding period (March–October) on a medium density population in which territories were partially contiguous. The territory size of adult fish varied between 3 and 26 m², and was inversely correlated with local densities of conspecifics. The same range in territory size was found for both males and females, which did not differ in the time they spent on territory defence and foraging activities. No correlation existed between territory size and the abundance of algal food, body size, age or time spent on territory defence. Also, there was little variation in territory size over time, despite seasonal changes in the abundance of food algae.Experimental reduction of food supplies on isolated territories of males and females had no effect on territory size. In a higher density habitat an experiment was carried out in which population density and food abundance were simultaneously manipulated. This showed that territory size was primarily determined by intraspecific interactions, as territories exhibited considerable increases in size upon removal of neighbours. No changes in the size of defended areas resulted from either artificial increases or decreases of food levels. There were also no changes in the time spent on defence of territories, foraging time or feeding rates associated with food manipulations or territory expansion, which suggested that food was not a limited resource. This conflicted with current theories proposed to explain territory defence and expansion. It is hypothesized that intraspecific interactions constrain territory size well below the optimum in terms of the abundance of preferred food algal species.     

Group size and composition are correlated with population density in the group-territorial blue korhaan (Eupodotis caerulescens)

The blue korhaan (Eupodotis caerulescens) is a poorly known bird endemic to the grasslands of southern Africa. It lives in permanently held territories defended by groups of individuals. During 2001 and 2002, 61 transects were carried out along 544 km of roads in Mpumalanga province (South Africa) to collect data on territory density and group size and composition in this species. Habitat, altitude and topography variables were measured to evaluate their influence on population density. Average territory density was 1.56 ± 0.19 (SE) territories per 5 km and maximum densities attained 5.6 territories per 5 km. Within its area of occurrence, higher densities occurred along transects with larger proportion of short grassland (either burned or grazed) and flatter topography. Mean group size was 3.03 ± 0.11 birds (n = 119), with 87.4% of the groups having one to four birds. Most common group composition was one male and one female‐like (34.5%), followed by two male and one female‐like (17.2%) and two male and two female‐like (13.8%). Single individuals were always males, and the male/female‐like ratio peaked at a group size of three and decreased thereafter. Mean group size increased with territory density (r_s = 0.42, P = 0.007, n = 41). There were no differences in group size across habitat types. The occurrence of habitat saturation and cooperative breeding in this species could explain the observed results.     

Density and productivity of breeding Skylarks Alauda arvensis in relation to crop type on agricultural lands in western France

Capsule Small field size and the maintenance of set-aside and lucerne are important to ensure high breeding pair densities and productivity.

Aims To investigate the effects of crop types and their attributes on density and productivity of breeding Skylark.

Methods At each of four selected study sites in western France, territory density, vegetation height, vegetation cover and field size was estimated by field and attempts were made to find nests. Crop types included winter and spring cereals, oilseed rape, sunflower, maize, grass, lucerne, set-aside, and bare ground.

Results About 80% of Skylark territories included more than one crop type. Birds preferred small fields and territory density decreased with increasing field size. Density was highest in crops with low vegetation height and cover. Set-aside, lucerne and grass supported highest territory density. Fledging productivity was highest in set-aside and lucerne, and was zero on bare ground. Skylark density decreased throughout the breeding season (-26% in 1999 and -29% in 2000), suggesting an instability in territory distribution or activity in intensive farmland.

Conclusions Farming systems that decrease field size and increase set-aside and lucerne instead of oilseed rape, maize and sunflower will benefit Skylark and other declining farmland species.     

The influence of food abundance,food dispersion and habitat structure on territory selection and size of an Afrotropical terrestrial insectivore

Most tropical insectivorous birds, unlike their temperate counterparts, hold and defend a feeding and breeding territory year-around. However, our understanding of ecological factors influencing territory selection and size in tropical insectivores is limited. Here we examine three prominent hypotheses relating food abundance, food dispersion (spatial arrangement of food items), and habitat structure to territoriality in the Usambara Thrush Turdus roehli. We first compared leaf-litter macro-invertebrate abundance and dispersion, and habitat structure between territories and random sites. We then examined the relation between these same ecological factors and territory size. Invertebrate abundance and dispersion were sparsely and evenly distributed across our study system and did not vary between territories and random sites. In contrast, habitat structure did vary between territories and random sites indicating the Usambara Thrush selects territories with open understorey and closed overstorey habitat. Invertebrate abundance and dispersion within territories of the Usambara Thrush were not associated with habitat structure. We believe the most likely explanation for the Usambara Thrush’s preference for open understorey and closed overstorey habitat relates to foraging behavior. Using information-theoretic model selection we found that invertebrate abundance was the highest-ranked predictor of territory size and was inversely related, consistent with food value theory of territoriality.     

Space and resource use by brown hyenas Hyaena brunnea in the Namib Desert

Two clans of brown hyenas were studied on the arid chilly Namib Desert coast where very large seal colonies are present. Carcasses from seals were abundant during summer and autumn following the seal pupping season, and scarce in winter and spring. Hyenas fed predominantly on carcasses. Members of one clan of three hyenas obtained most of their food along 3 km of coastline adjacent to the seal colonies. The other clan of nine individuals obtained food from an area along 6 km of coastline north of the seal colonies. Although carcasses were usually scavenged, seal pups were seen to be killed on occasions. Time spent foraging was not affected by carcass availability. Territories of the two clans overlapped and individual home-range size varied from 31.9 to 220 km². Food availability apparently had no influence on foraging activities but the dispersal of food affected territory and group sizes. Over abundance of food results in the maintenance of territories extending beyond the distribution of food. The shape and area of these territories may result from the cultural inheritance of space.     

Prior residence, territory quality and life-history strategies in juvenile Atlantic salmon (Salmo salar L.)

Three groups of juvenile salmon were introduced sequentially into an artificial stream to investigate the effects of prior residence on behaviour and territory choice. Almost half of the first group obtained and defended distinct territories, the other half being constrained to an area approximately the size of one large territory. All of the fish in the subsequent groups, bar one, were also constrained to the same site. Since the fish were of similar size, prior residence alone seemed to influence which individuals obtained territories. However, within the first group, the fish that obtained territories were larger and more aggressive. The territorial fish did not appear to choose the most profitable territories, although they had the greatest opportunity to do so. Since juvenile salmon emerge from their gravel nests fairly synchronously, a time constraint on site sampling is hypothesised: there may be a risk in taking time to sample sites, since these same sites may become occupied with conspecifics. However, fish with territories fed at faster rates than non-territorial fish, possibly because of reduced competition for prey items. Consequently, fish from the first group (containing most of the territorial fish) grew faster than the other two groups. Moreover, most of the territory holders, but only one of the non-territorial fish, reached the threshold size that increases their probability of smolting the following year. This suggests that ability to obtain a defensible territory, primarily through prior residence, influences the age at which juvenile salmon can migrate to sea.     

Prey availability affects territory size,but not territorial display behavior,in green anole lizards

The availability of food resources can affect the size and shape of territories, as well as the behaviors used to defend territories, in a variety of animal taxa. However, individuals within a population may respond differently to variation in food availability if the benefits of territoriality vary among those individuals. For example, benefits to territoriality may differ for animals of differing sizes, because larger individuals may require greater territory size to acquire required resources, or territorial behavior may differ between the sexes if males and females defend different resources in their territories. In this study, we tested whether arthropod abundance and biomass were associated with natural variation in territory size and defense in insectivorous green anole lizards, Anolis carolinensis. Our results showed that both male and female lizards had smaller territories in a habitat with greater prey biomass than lizards in habitats with less available prey, but the rates of aggressive behaviors used to defend territories did not differ among these habitats. Further, we did not find a relationship between body size and territory size, and the sexes did not differ in their relationships between food availability and territory size or behavioral defense. Together, these results suggest that differences in food availability influenced male and female territorial strategies similarly, and that territory size may be more strongly associated with variation in food resources than social display behavior. Thus, anole investment in the behavioral defense of a territory may not vary with territory quality.