Foraging theory upscaled: the behavioural ecology of herbivore movement

We outline how principles of optimal foraging developed for diet and food patch selection might be applied to movement behaviour expressed over larger spatial and temporal scales. Our focus is on large mammalian herbivores, capable of carrying global positioning system (GPS) collars operating through the seasonal cycle and dependent on vegetation resources that are fixed in space but seasonally variable in availability and nutritional value. The concept of intermittent movement leads to the recognition of distinct movement modes over a hierarchy of spatio-temporal scales. Over larger scales, periods with relatively low displacement may indicate settlement within foraging areas, habitat units or seasonal ranges. Directed movements connect these patches or places used for other activities. Selection is expressed by switches in movement mode and the intensity of utilization by the settlement period relative to the area covered. The type of benefit obtained during settlement periods may be inferred from movement patterns, local environmental features, or the diel activity schedule. Rates of movement indicate changing costs in time and energy over the seasonal cycle, between years and among regions. GPS telemetry potentially enables large-scale movement responses to changing environmental conditions to be linked to population performance.     

基于传感器标记的野生动物追踪技术在中国的应用现状与展望

对动物的标记、定位与追踪是研究其空间运动的重要途径。自20世纪80年代起, 以动物个体佩戴的传感器为核心的野生动物追踪技术被引入我国, 广泛用于野生动物行为与生态研究。为全面地了解中国野生动物追踪技术的应用现状, 本研究系统检索了1970-2022年间在中国开展的野生动物追踪研究论文, 统计并汇总了基于传感器的追踪技术类别、应用动物类群、研究领域及研究地点等信息。本研究共收集到论文519篇, 涵盖了分属7纲32目的共计185个物种。动物追踪研究地点覆盖我国34个省(直辖市、自治区、特别行政区), 其中最为集中的区域主要包括青藏高原东缘及周边山地、长江中下游区域、华东至华南沿海以及东北地区。所使用的技术类别包括5类: 无线电遥测(RT)技术(占总研究数量的47.7%)、无线射频识别(RFID)技术(3.2%)、光敏全球定位传感器(GLS)技术(0.6%)、基于Argos系统(ASS)的卫星追踪技术(9.3%)、基于全球定位导航系统(GNSS)的卫星追踪技术(39.3%)。在各类技术中, 甚高频(VHF) RT技术是我国使用历史较长、数量较大的技术; ASS和GNSS技术引入较晚, 但增长迅速, 其中GNSS技术在近5年来已经成为应用最多的技术。RT技术在大中型哺乳动物、小型哺乳动物、陆禽鸟类以及两栖、爬行动物追踪中应用最多, 游禽与涉禽鸟类的追踪以GNSS技术为主, 鱼类追踪研究中ASS技术应用较多, 而无脊椎动物的追踪研究则主要使用RFID技术。不同的研究领域中所使用的技术类别存在差异, 其中迁徙研究主要应用GNSS和ASS卫星追踪技术。本研究的结果表明, 基于传感器的野生动物标记、定位与追踪技术在我国的应用规模正在快速扩大, 标记动物数量、累积数据量快速增加。今后, 中国的野生动物追踪研究应进一步扩展研究深度和广度, 加强多学科合作与技术创新, 倡导并推动数据共享与合作, 并进一步推动国产追踪设备及技术的研发与完善, 从而为我国野生动物生态研究与资源保护管理提供可靠的科学支持。     

Evolution of community composition in several carnivore palaeoguilds from the European Pleistocene: the role of interspecific competition

This study focuses on ecological processes such as competition or predation from an evolutionary perspective. First, we attempt to test the idea that species with similar feeding requirements tend to coexist by separating morphologically or behaviourally. Then, the Barton–David test was applied to several carnivore communities (felids and canids) separated in time. Although the preservation bias of the fossil record renders our conclusions tentative, the general equal size–ratio pattern in most of the guilds examined indicates that inter-specific competition for prey species seems to be a good candidate to explain the evolution of guild composition and morphological traits throughout the Pleistocene for the two groups considered, felids and canids.     

Homing movements of displaced stream-dwelling brown trout

In April and May of 1993, 12 of 14 brown trout (202–288 mm), tagged with radio transmitters and displaced over 800–3600 m in a natural river system, returned to the areas from which they were captured. Homing was generally directed and rapid (up to 1·22 body lengths s⁻¹ against the flow). Homing commenced within 65 min of displacement for four of five trout displaced downstream, and within 4 days for those displaced above the confluence of a home tributary burn with the main stem of the river.     

Movement activity and habitat use of Carabus ullrichii (Coleoptera: Carabidae): The forest edge as a mating site?

Some carabid species are not restricted to a single habitat only, but use various types of habitats. In these species, relatively little is known about the utilization of occupied habitats and factors affecting their movement within these habitats. In this study, we focus on the movement activity of ubiquitous Carabus ullrichii during its reproductive period at the border of two types of habitats, a meadow and a forest. We tracked 21 adult individuals using radio telemetry and recorded in total 1,687 position fixes. Movement activity was associated with the type of habitat and specific environmental conditions such as time of the day and air temperature. Both sexes activated preferably at dusk and during the night, although males were most active at temperatures around 15°C, while females showed no preference for temperature. Males were able to walk as fast as females, but they were more associated with forest edge. We assume that the inner edge of the forest could be used as a mating site and after mating males stay there and wait for new females with which to mate, while fertilized females disperse into the surroundings. They moved further into the closed forest where they were likely looking for oviposition sites and food resources to support reproduction. Exclusively females were recorded to visit the meadow at a greater distance from the forest edge and their movements there were almost always direct.     

Energetics and space use: intraspecific and interspecific comparisons of movements and home ranges of two Colubrid snakes

1. Energy requirements explain substantial variation in movement and home range size among birds and mammals. This study assesses whether the same is true of snakes by comparing ratsnakes (Elaphe obsoleta) and racers (Coluber constrictor), ecologically similar species whose energy requirements appear to differ substantially (racers > ratsnakes). 2. Over 4 years 22 Elaphe and 16 Coluber were radio-tracked at the same site in Illinois to examine how movement and home ranges varied by sex and season. 3. Coluber moved more often and further per move than Elaphe, resulting in their estimated mean day range being almost four times larger than that of Elaphe (88.0 m day(-1) vs. 23.1 m day(-1)). 4. Both male and female Elaphe moved more frequently early in the season consistent with mate-searching, but mean distances moved did not differ seasonally or by sex. Both sexes of Coluber moved more later in the season and overall males moved further than females. 5. Interspecifically, patterns were consistent with the energetics hypothesis--Coluber had mean home ranges approximately four times larger than those of Elaphe. 6. Intraspecifically, increased movement did not always produce larger home ranges. Male Elaphe had larger home ranges than females despite not moving further, whereas male Coluber had comparable home ranges to females despite moving further. Also, Elaphe home ranges in Illinois were substantially smaller than has been documented in Ontario, despite Ontario Elaphe moving less. 7. Our results generally support the energetics hypothesis, but indicate that knowledge of ecology and energetics increases our understanding of area requirements beyond simple allometric predictions.