The effect of vegetation cover on vigilance and foraging tactics in the fat sand rat Psammomys obesus

The combination of the visual obstruction and protection properties of vegetation is considered to be one of the most important factors determining the trade-off between vigilance and foraging in a prey species. In the Negev desert, diurnal fat sand rats construct their burrows in the ephemeral river beds ("wadis"), under dense and tall shrubs of Atriplex halimus, or on the open first fluvial terrace, covered with scattered low shrubs of Anabasis articulata. We tested the hypothesis that properties of the vegetation would affect the time budget of female sand rats. Sand rats spent more time aboveground, rested more, were less vigilant, and moved more slowly under the dense cover in the wadi than at the open terrace. No differences in the total foraging time were revealed, but foraging tactics varied between habitats: individuals in the wadi mainly fed aboveground, whereas those at the terrace mainly hoarded. Our results indicate that sand rats perceive the dense vegetation cover as good protection despite its visual obstructive nature, and that vigilance in Psammomys obesus is performed at the cost of resting rather than at the cost of foraging. Received: January 15, 2001 / Accepted: April 17, 2001     

新疆准噶尔盆地东部波斑鸨秋季栖息地选择

2000年9月,利用粪便示踪和野外直接观察法对准噶尔盆地东部波斑鸨（Chlamydotis undulata)秋季栖息地进行了采样调查。结果表明：波斑鸨秋季栖息地地热平坦,视野开阔,广泛分布旱生和盐生荒膜植物,植被稀疏、低矮,并镶嵌有相对较高的灌丛块;影响波斑鸨秋季栖息地选择的环境因子是植被密度、物种丰富度和物候;秋季栖息地内的植被密度、草木植物种数、叉毛蓬密度、结实植物密度和物种数都极显著高于对照地内的相应成分;生长植物密度显著高于对照地;而假木贼密度和琵琶柴密度显著低于对照地。     

Density dependence in foraging habitat preference of eastern grey kangaroos

For a free‐ranging forager, the suitability of a patch is dependent on population density, resource supply, resource quality, and the costs of foraging or dispersal. We quantified differences among three foraging habitats and compared this variation to temporal patterns of habitat preference by free‐ranging eastern grey kangaroos, Macropus giganteus. We investigated selection on a fine‐grained spatial scale, and asked whether habitat preference is constrained by density‐dependent mechanisms. Variation in the quantity and quality of resources among habitats was greatest during spring, when biomass and quality were highest, and differences among habitats were most pronounced. However, consistent and discernable differences among habitats were not obtained, indicating that the system fluctuated around an equilibrium state. Using isodar regressions to examine the consumer‐density relationships among habitats, open‐woodland habitat was favoured over the two open‐forest habitats for foraging. Seasonal isodars indicated that density dependence regulated preference between the three foraging habitats during autumn, spring and summer, but not during winter, when variability in resources among habitats was lowest.     

深圳湾不同生境湿地大型底栖动物次级生产力的比较研究

以深圳湾红树林为例,于2010年1—12月每月1次对红树林和3种对照生境(芦苇鱼塘,基围鱼塘和光滩)的大型底栖动物进行了采样调查,并对其次级生产力、P/B值(次级生产力与生物量的比值)、优势种和生物多样性进行了计算与分析。结果表明,不同生境大型底栖动物群落次级生产力和P/B值差异明显,芦苇鱼塘、基围鱼塘、光滩和红树林生境的次级生产力分别为:6.81、147.50、74.70和105.78 g.m-.2a-1;P/B值分别为:1.10、1.53、1.41和3.58 a-1。红树林生境的次级生产力较高,仅次于基围鱼塘,P/B值显著高于其他3种生境,周转速率最快。结合大型底栖动物优势种和生物多样性的季节变化分析表明,红树林生境大型底栖动物生物多样性最丰富,生态系统抵抗力和恢复力最高,生态系统最稳定。由此说明城市化地区红树林生境对大型底栖动物周转速率和物种多样性有明显促进作用,可以增加生态系统营养的保持力和生态系统的稳定性,对于缓解城市化对湿地生态系统造成的威胁具有重要作用。     

Density-dependent habitat selection between maize cropfields and their borders in two rodent species (Akodon azarae and Calomys laucha) of Pampean agroecosystems

We studied habitat preferences and intra and interspecific density-dependent effects on habitat selection by Akodon azarae and Calomys laucha between maize fields and their adjacent borders, during different developmental stages of the crop. Akodon azarae detected quantitative differences between habitats, using preferentially borders throughout the year, while C. laucha perceived borders and cropfields as quantitatively similar during spring and summer and it detected borders as quantitatively better at the high density period (autumn and winter). These results support the prediction of differential habitat preferences as a model of community organisation at the low density period, while they are consistent with shared habitat preferences during autumn and winter when both species apparently coexist in the better habitat (border). Akodon azarae showed intraspecific density-dependent habitat selection throughout the year, except in spring, while habitat selection by C. laucha was density-dependent in spring, autumn and winter. The effect of interspecific density on habitat selection was detected in both habitats and changed seasonally. The effect of A. azarae over C. laucha by resources exploitation was detected in borders, while competitive effects of C. laucha over A. azarae was observed within cropfields. Both species were more affected by exploitation competition than interference, which was more common in borders than in maize fields. We conclude that seasonally have a profound effect in habitat selection of these species because it changes the intensity of intra and interspecific competition and affects different habitat preferences and basic suitability of habitats. This revised version was published online in November 2006 with corrections to the Cover Date.     

Parental overwintering history affects the responses of Thlaspi arvense to warming winters in the North

The overwintering conditions of northern plants are expected to change substantially due to global warming. For perennial plants, winter warming may increase the risk of frost damage if the plants start dehardening prematurely. On the other hand, evergreen plants may remain photosynthetically active and thereby benefit from milder winters. The positive and negative effects of mild winters on annual plants remain, however, largely unknown. We postulated that summer annuals may be susceptible to frost damage if the seeds germinate during a mild spell in winter. Winter annuals may utilize a warm period for photosynthesis. These questions were addressed in two consecutive experiments in which pot-grown individuals of Thlaspi arvense that overwintered in the field were exposed to an elevated temperature for 8 days in growth chambers in mid-winter. No premature germination was observed in summer annuals. However, in accordance with our hypothesis, winter annuals started photosynthesising very rapidly upon exposure to elevated temperature. The winter warming treatment affected neither the total number of seeds produced nor the mean seed weight. These seeds, possessing divergent parental overwintering histories, were used as starting material for the second experiment. Seeds originating from both summer and winter annual plants germinated both in the autumn and in the following spring. We observed a major parental effect associated with the winter warming treatment. The warm spell experienced by the mother plant (either as a winter annual rosette or as a summer annual seed) reduced the proportion of autumn germination in the next generation. Only 43% of the seeds of summer annuals possessing a parental warming history germinated before the winter, whereas the germination percentage of seeds with no previous winter warming history was 71%. In the case of seeds collected from winter annual plants, 4% of the seeds germinated in autumn if the mother plants experienced the warming treatment during the previous winter, whereas the corresponding value was 37% if the mother plants did not experience warming. Our results show that summer and winter annual individuals show diverse responses to warm spells in winter. Since the responses are not limited only to the generation that actually experiences the warm spell, but also appear in their offspring, long-term studies consisting of several generations are called for.     

Food resources of the wild Barbary macaque (Macaca sylvanus) in high-altitude fir forest, Ghomaran Rif, Morocco

A small geographically isolated population of the Barbary macaque inhabits a high-altitude fir forest habitat ( Abies pinsapo ) in the Ghomaran region of the Rif mountains of northern Morocco. The climate of this region is Mediterranean, but the altitude (1600–2100 m) causes winters to be cold (as low as -8.0 C) with snow occurring from November to May (snowfall as deep as 1.5 m). The primary winter feeding adaptation is the ability to ingest high quantities of fir foliage; in spring, the macaques took a high diversity of leafy food items from all vegetation layers; in summer, the macaques foraged terrestrially for a high diversity of food items including seeds, small fruits, bulbous geophytes, and animal foods (including tadpoles from small streams); in autumn, the macaques returned to arboreal foraging, primarily feeding on oak acorns ( Quercus ilex ), fir seeds and yew fruit ( Taxus baccata ). The macaques were capable of ingesting 100 of 195 (51%) of all identified plant species in the region, although during the four-month winter, the macaques only averaged 12.5 common food items. A comparison of the study area with the prime habitat of the Barbary macaque-the high-altitude cedar forests of the Moroccan Moyen Atlas-indicates that climate and vegetation physiognomy are highly similar in both regions. Correspondingly, there is a high degree of similarity in macaque diet in both regions in terms of feeding behaviour by season, food diversity and specific feeding techniques. In the Ghomara, the winter feeding adaptation of fir foliage eating parallels that of the Barbary macaque in cedar forest (winter foraging for cedar foliage). This enables the Barbary macaque to exploit the Ghomaran fir forest habitat during the cold, snowy winters much the same as it does cedar forest habitat throughout a major portion of its geographical range.     

基于MAXENT模型的古田山保护区黑麂生境适宜性评价

浙江开化古田山国家级自然保护区是黑麂（Muntiacus crinifrons）的集中分布区之一。近年来,保护区内黑麂面临着生境丧失和破碎化的威胁。本研究应用MAXENT模型,结合古田山保护区2014-2017年的红外相机监测数据和主要环境变量数据,对保护区内黑麂生境适宜性的季节变化特征及影响因素进行了评价与分析。结果表明：距阔叶林距离、海拔两个变量对黑麂生境适宜性的季节性变化影响最为显著。古田山保护区不同季节黑麂的适宜生境面积为：春季2086.38 hm²、夏季2608.74 hm²、秋季2502.27 hm²和冬季1746.27 hm²,分别占保护区总面积的25.74%、32.18%、30.87%和21.54%。从空间分布来看,黑麂适宜生境主要分布在保护区的核心区和北部区域。建议加强对保护区的核心区和北部区域自然植被的保护与恢复,以及对保护区人为干扰活动的监督和管理。     

Brown bear habitat selection in relation to anthropogenic structures in the Bieszczady Mountains,Poland

In Europe, brown bear Ursus arctos habitats frequently overlap with human settlements and infrastructure. We tested whether anthropogenic structures played an important role in habitat selection by brown bears in the Bieszczady Mountains, Poland. We analysed 668 signs of brown bear presence recorded during 6 counts along 246 km of transects (total 1,476 km) in spring, summer and autumn of 1993 and 1994. Habitat selection of bears was more related to habitat and altitude than to human factors. Avoidance of roads, settlements and forest clearings influenced habitat selection by brown bears in spring but less in summer and autumn.     

Local and seasonal variations of roe deer diet in relation to food resource availability in a Mediterranean environment

Feeding behaviour patterns of European roe deer are well known but not in their southern range, where in contrast to Central and northern Europe the climate is characterised by mild winters, but hot and dry summer months. Spatial and temporal variations of the roe deer diet were investigated by analyses of 597 faecal samples in a coastal area in Italy. The aim was to evaluate the adaptive strategies of dietary intake to seasonal availability of different forage types in areas of fairly natural Mediterranean scrubwood and different areas dominated by agricultural habitats. A wide range of plant taxa (151 species/genera) was used, belonging to eight categories. A gradient was found from a diet dominated by woody plants and fruits in natural habitats to one characterised by cultivated plants in the agricultural areas. Usage of forage categories in areas dominated by woodland was proportional to their availability, whereas diet selection was found in the agricultural habitats, particularly marked in summer, the time at which food quantity and quality decreased due to harvest and drought. As to seasonal variation, the summer and autumn diets included more deciduous browse, whereas the winter diet was characterised by an increasing use of cereals and grass. In most areas, half-woody browse and fruit were preferred; grass and cereals were used less than expected by their availability. Most probably, selective behaviour patterns are linked to the difference of quality between plants together with their variable abundance, which is more evident in agricultural areas than in the woodland.     

云南大中山黑颈长尾雉栖息地选择周年变化

采用比较利用和可利用栖息地的方法,分别对云南大中山黑颈长尾雉秋冬季、春季和夏季栖息地展开调查。检验和Bonferroni置信区间分析结果表明,黑颈长尾雉不同季节均偏向选择常绿阔叶林,偏向选择或回避选择的乔木、灌木和草本的种类不尽相同。利用和可利用样方差异性检验显示,不同季节对地形因素的选择性不明显,仅夏季距水源距离一个因子差异显著;植被因子中,春季差异显著的仅有乔木层盖度因子,夏季有乔木密度、乔木层盖度、落叶层盖度和草本层盖度等4个因子,秋冬季有乔木层盖度、草本层盖度和藤本密度等3个因子。主成分分析表明,不同季节利用样方负荷绝对值较大的因子在各主成分中的序位不尽相同,即栖息地选择的主要生态因子随季节发生变化。单因素方差分析和逐步判别分析表明,秋冬季与春季栖息地特征较接近,而与夏季差别较大。χ2     

Seasonality and edge effect determine herbivory risk according to different plant association models

We report evidence of hierarchical resource selection by large herbivores and plant neighbouring effects in a Mediterranean ecosystem. Plant palatability was assessed according to herbivore foraging decisions. We hypothesize that under natural conditions large herbivores follow a hierarchical foraging pattern, starting at the landscape scale, and then selecting patches and individual plants. A between- and within-patch selection study was carried out in an area formed by scrubland and pasture patches, connected by habitat edges. With regard to between-patch selection, quality-dependent resource selection is reported: herbivores mainly consume pasture in spring and woody plants in winter. Within-patch selection was also observed in scrub habitats, influenced by season, relative patch palatability and edge effect. We defined a Proximity Index (PI) between palatable and unpalatable plants, which allowed verification of neighbouring effects. In spring, when the preferred food resource (i.e. herbs) is abundant, we observed that in habitat edges large herbivores basically select the relatively scarce palatable shrubs, whereas inside scrubland, unpalatable shrub consumption was related to increasing PI. In winter, a very different picture was observed; there was low consumption of palatable species surrounded by unpalatable species in habitat edges, where the latter were more abundant. These outcomes could be explained though different plant associations described in the literature. We conclude that optimal foraging theory provides a conceptual framework behind the observed interactions between plants and large herbivores in Mediterranean ecosystems.     

Lapwings Vanellus vanellus on aerodromes and the birdstrike hazard

Habitat selection by Lapwings Vanellus vanellus varies seasonally, with aerodromes comprising a preferred habitat in late summer and again in late autumn and winter. The presence of flocks of Lapwings on aerodromes poses a flight safety problem but management of the aerodrome habitat, especially the grass areas, combined with scaring, can minimize the hazard. The consequences of displacing large numbers of Lapwings from aerodromes to other habitats are reviewed in relation to the declines in breeding populations that have occurred as a result of changes in agricultural practices.     

Effects of predation-risk on habitat use by Himalayan Snowcocks

Summary When given a choice, animals often prefer foraging habitats where predation risk is low, even if such habitats provide reduced foraging opportunities. We evaluated foraging rates of tame but free-ranging Himalayan Snowcocks (Tetraogallus himalayensis) in 16 types of alpine habitats. Foraging rate was highest on level or slightly-sloping terrain and where grasses were relatively abundant. We also observed 102 wild snowcocks and found they were most nervous about raptorial predators when on level or slightly-sloping terrain and in small coveys. Snowcocks face a dilemma: they are most vulnerable to raptors in areas where they can forage most efficiently. During summer snowcocks trade off higher foraging efficiency on level terrain for lower predation risk on steeper terrain. During winter, when raptor numbers are lower, snowcocks apparently revert to using level or slightly-sloping, high-efficiency foraging habitats. Risk of predation plays an important role in habitat selection and resource utilization by snowcocks.     

The habitat use and diet of Black Grouse Tetrao tetrix in the Pennine hills of northern England

The habitat and dietary preferences of Black Grouse were studied from 1989 to 1991 in a largely treeless habitat within a 17 km² area of the Pennine hills of northern England using radiotelemetry. Grassland habitats were preferred by 84% of 19 birds for much of the year and heather moorland was selected in winter; the other birds, all females, remained in heather habitats all year. Most females reared broods in damp, rushy grass moorlands, but one of six broods used hay fields. Diet closely reflected seasonal plant availability in selected habitats and the leaves, flowers, fruits and seeds of a wide variety of plants were eaten. Cotton-grass Eriophorum vaginatum was important in spring, grassland herbs, grasses, sedges and rushes in summer and autumn and Ling Heather Calluna vulgaris in late autumn and winter. Males fed substantially more on heather in winter than females which partially replaced heather in their diet with the leaves of grasses and herbs. Young chicks showed considerable preference for Sawfly (Symphyta) larvae. Suggested management recommendations include the regulation of sheep-grazing, encouragement of wet flush areas and the late cutting of hay fields.     

贵州草海越冬黑颈鹤觅食栖息地选择的初步研究

本文报道了利用Friedman非参数统计方法,研究越冬黑颈鹤(Grus nigricollis)在贵州草海对其觅食栖息地选择的结果。在草海的黑颈鹤越冬觅食栖息地可分为5种——莎草草甸、浅水沼泽、草地、玉米地和蔬菜地。黑颈鹤对莎草草甸的选择性最高,对玉米地的选择性最差,对其余类型栖息地的选择随地点的不同而不同。草海的人为活动很多,是影响黑颈鹤利用和选择栖息地的一个重要因素。本文也对改善黑颈鹤越冬栖息地的管理和保护提出了一些建议。     

短尾猴栖息地的季节变化

本文阐述了短尾猴栖息地的季节变化。春季,主要利用海拔570-1600米的常绿阔叶林、常绿、落叶阔叶混交林和落叶阔叶林;夏季,限于海拔1000米以上的落叶阔叶林。秋季的栖息地,在海拔650-1200米常绿阔叶林和常绿、落叶阔叶混交林;冬季仅利用海拔600-900米的常绿阔叶林。此外还报道了短尾猴四季的食物组成。并对栖息地的变化原因,做了初步探讨。     

Nocturnal foraging habitats of French and bluestriped grunts,Haemulon flavolineatum and H. sciurus,at Tobacco Caye,Belize

Synopsis Nocturnal foraging habitats of Haemulon flavolineatum and H. sciurus were investigated in the backreef habitat around Tobacco Caye, Belize. Grunts leave the reef at dusk to forage in the grass beds and sand flats surrounding the reef. The hypothesis that French and bluestriped grunts use separate foraging habitats was examined by following tagged fishes from their diurnal territories or schooling sites to nocturnal foraging grounds. The tag consisted of a small, glowing Cyalume light stick sutured to the dorsal musculature of the fish, next to the first dorsal fin. Surveys of foraging habitats were done to support the tracking study. Large quadrats (225 m²) were set out over the sand flats and grass beds during the day. The numbers of French and bluestriped grunts feeding in each habitat were counted one hour after dark. Foraging French grunts used sand flats, whereas bluestriped grunts usually fed in grass beds. Repeated sightings of two French grunts and one bluestriped grunt in the same individual night-time locations support the hypothesis that nocturnal foraging sites may be used repeatedly by the same individuals.     

Habitat use and selection by Red-crowned Crane Grus japonensis in winter in Yancheng Biosphere Reserve, China

We report the distribution and habitat selection by the Red-crowned Crane Grus japonensis in winter in the Yancheng Biosphere Reserve, China. Including original wetlands and artificial habitats, six types of habitat are used by the species: saltworks (salinas), fish ponds, reed beds, Wormwood Artemisia halodendron beaches, tidal grasslands and wheat fields. We compared the habitat availability with habitat use in each type. In winter, Red-crowned Crane preferentially used tidal grasslands and fish ponds. Saltworks, Wormwood beaches and wheat fields were avoided. The distribution of Red-crowned Crane in different types of habitat changed with the distribution of freshwater and with human activities.     

Multi-scale habitat selection and foraging ecology of the eurasian hoopoe (<Emphasis Type="Italic">Upupa epops</Emphasis>) in pine plantations

Bird conservation can be challenging in landscapes with high habitat turnover such as planted forests, especially for species that require large home ranges and juxtaposition of different habitats to complete their life cycle. The eurasian hoopoe (Upupa epops) has declined severely in western Europe but is still abundant in south-western France. We studied habitat selection of hoopoes in pine plantation forests using a multi-scale survey, including point-counts at the landscape level and radio-tracking at the home-range scale. We quantified habitat use by systematically observing bird behaviour and characterized foraging sites according to micro-habitat variables and abundance of the main prey in the study area, the pine processionary moth (Thaumetopoea pityocampa). At the landscape scale, hoopoes selected habitat mosaics of high diversity, including deciduous woods and hedgerows as main nesting sites. At the home-range scale, hoopoes showed strong selection for short grassland vegetation along sand tracks as main foraging habitats. Vegetation was significantly shorter and sparser at foraging sites than random, and foraging intensity appeared to be significantly correlated with moth winter nest abundance. Hoopoe nesting success decreased during the three study years in line with processionary moth abundance. Thus, we suggest that hoopoes need complementation between foraging and breeding habitats to establish successfully in pine plantations. Hoopoe conservation requires the maintenance of adjacent breeding (deciduous woods) and foraging habitats (short swards adjacent to plantation edges), and consequently depends on the maintenance of habitat diversity at the landscape scale.