Dispersing brush mice prefer habitat like home

During natal dispersal, young animals leave their natal area and search for a new area to live. In species in which individuals inhabit different types of habitat, experience with a natal habitat may increase the probability that a disperser will select the same type of habitat post-dispersal (natal habitat preference induction or NHPI). Despite considerable interest in the ecological and the evolutionary implications of NHPI, we lack empirical evidence that it occurs in nature. Here we show that dispersing brush mice (Peromyscus boylii) are more likely to search and settle within their natal habitat type than expected based on habitat availability. These results document the occurrence of NHPI in nature and highlight the relevance of experience-generated habitat preferences for ecological and evolutionary processes.     

Spawning habitat selection and suitability for Japanese dace, Tribolodon hakonensis

We have investigated the effects of three current velocities and three substrate sizes (gravel to cobble) on the spawning behavior of Japanese dace, Tribolodon hakonensis, in spawning-induction and habitat-selection experiments. In the spawning-induction experiment under laboratory conditions the number of females induced to spawn was significantly fewer at low current velocity (ca. 5 cm s^–1) than at medium (ca. 30 cm s^–1) or high (ca. 50 cm s^–1) current velocity. Females spawned independently of substrate size in the experimental tank, and did not bury their eggs in the substrate bed. In the habitat-selection experiment under field conditions, females selected the substrate microhabitat and spawned more frequently at a site with medium substrate size (very coarse gravel; major axis ca. 40 mm) than at sites with small (fine gravel; ca. 8 mm) or large (cobble; ca. 70 mm) substrate size. We conclude that Japanese dace select spawning sites at least partly on the basis of current velocity and substrate size, which affects the survival rate of eggs.     

Density-dependent habitat selection: Testing the theory with fitness data

Summary According to density-dependent habitat selection theory, reproductive success should decline with increased density. Fitness should be similar between habitats if habitat selection follows an ideal free distribution; fitness should be dissimilar between habitats if habitat selection is modified by territorial behavior. I tested these assumptions by examining a variety of fitness estimates obtained from white-footed mice living in nest boxes in forest, forest edge and fencerow habitats in southwestern Ontario. As expected, mean litter size declined with increased population density. Litter sizes, adult longevity and the proportion of adult animals in breeding condition were not significantly different among the three habitats. The success at recruiting at least one offspring to the adult population and the number of recruits per litter were much greater in the forest than in either of the other two habitats. Fitness was thus unequal among habitats and the results confirm both assumptions of density-dependent habitat selection theory for territorial white-footed mice.     

Life histories and habitat selection in Daphnia: divergent life histories of D. magna clones differing in phototactic behaviour

To test the hypothesis of co-adaptation of life histories and daytime vertical distribution (vertical migration behaviour) in Daphnia, life history characteristics were analysed for two positively, three negatively, and four intermediately phototactic Daphnia magna clones. Clones with different phototactic behaviour were found to have divergent life history strategies, with positively phototactic clones being good exploiters under the non-limiting conditions provided in the laboratory, i.e. low density (1 ind./1), high food concentration (6,5–7 10⁵ Scenedesmus cells/ml, restored daily) and high temperature (20° C). They realized a high intrinsic rate of increase at a small adult body size through rapid development, at a cost of producing small neonates. Negatively and intermediately phototactic clones had larger adult body sizes, and produced larger neonates that were more starvation-resistant than those of positively phototactic clones. Selection for high intrinsic rate of increase in intermediately phototactic clones was mediated through the production of large clutches.     

Environmental constraints on life histories in Antarctic ecosystems: tempos, timings and predictability

Knowledge of Antarctic biotas and environments has increased dramatically in recent years. There has also been a rapid increase in the use of novel technologies. Despite this, some fundamental aspects of environmental control that structure physiological, ecological and life-history traits in Antarctic organisms have received little attention. Possibly the most important of these is the timing and availability of resources, and the way in which this dictates the tempo or pace of life. The clearest view of this effect comes from comparisons of species living in different habitats. Here, we (i) show that the timing and extent of resource availability, from nutrients to colonisable space, differ across Antarctic marine, intertidal and terrestrial habitats, and (ii) illustrate that these differences affect the rate at which organisms function. Consequently, there are many dramatic biological differences between organisms that live as little as 10 m apart, but have gaping voids between them ecologically.Identifying the effects of environmental timing and predictability requires detailed analysis in a wide context, where Antarctic terrestrial and marine ecosystems are at one extreme of the continuum of available environments for many characteristics including temperature, ice cover and seasonality. Anthropocentrically, Antarctica is harsh and as might be expected terrestrial animal and plant diversity and biomass are restricted. By contrast, Antarctic marine biotas are rich and diverse, and several phyla are represented at levels greater than global averages. There has been much debate on the relative importance of various physical factors that structure the characteristics of Antarctic biotas. This is especially so for temperature and seasonality, and their effects on physiology, life history and biodiversity. More recently, habitat age and persistence through previous ice maxima have been identified as key factors dictating biodiversity and endemism. Modern molecular methods have also recently been incorporated into many traditional areas of polar biology. Environmental predictability dictates many of the biological characters seen in all of these areas of Antarctic research.     

The evolution of parental care in shorebirds: life histories, ecology, and sexual selection

Parental care is expected to evolve according to a trade-offbetween the benefits of increased survival of offspring andcosts of reduced survival and future reproduction of adults.Here we investigate the components of this life-history trade-offin shorebirds (Charadriides, excluding Laroidea), an avian infraorderdisplaying an unusual diversity in extent of care by each sex.We show that evolutionary increases in the duration of carein one sex are associated with decreased care by the other.We found no evidence that various hypothesised benefits of careprovide a general explanation for the duration of care by eitheror both sexes, although parental feeding of the young was tooconservative for comparisons. Sexual dimorphism in body sizehad a similar relationship to parental care in both sexes: reductionsin duration of care by either sex were matched by increasesin the size of that sex relative to the other. Whereas thispattern could be explained by sexual selection in males, itwas retained within socially monogamous females. Reduced carein males (but not in females) appears to have facilitated theevolution of greater migration distances. These results suggestthat parental care has had different causes and consequencesin each sex. Benefits of desertion due to sexual selection aremore clearly demonstrable for males, whereas correlates of careare less clear for females     

Different growth responses to temperature and resource limitation in three fly species with similar life histories

Growth responses to temperature and resource limitation in three dipteran species with similar life histories were compared. With respect to current life history theory, two points are raised. First, growth rate in real time increased steeply with temperature in all species, following the standard pattern. However, when expressed in physiological time growth rate increased as temperature decreased in the yellow dung fly Scathophaga stercoraria, remained approximately constant in Sepsis cynipsea, and increased in Drosophila melanogaster. These responses can be understood as adaptations to climate and seasonality. It is concluded that some patterns of adaptation may be more easily interpreted if, and some may even go undetected unless, they are analysed in physiological time. Second, a decrease in body size, development rate and growth rate when resources are limited is believed to be nearly universal and generally predicted by life history models. Despite their similar life histories, the three species investigated showed qualitatively different growth responses to larval food shortage. At unlimited resources, yellow dung flies showed the fastest initial larval body mass gain per unit time, while those of S. cynipsea and D. melanogaster were lower and about equal. The period of no body mass gain at the end of larval development was longest in S. stercoraria and shortest in S. cynipsea. When facing resource limitation, S. stercoraria emerged smaller but earlier (thus nearly maintaining their growth rate), S. cynipsea smaller after the same development period, and D. melanogaster smaller and later (showing reduced and much reduced growth, respectively). It is concluded that whether growth really slows when resources are limited depends on the precise ecological circumstances of the species in question. More refined models, particularly those where mortality costs are independent of time, and more experiments are necessary to account for the variation in growth and size and age at maturity present in nature. This revised version was published online in July 2006 with corrections to the Cover Date.     

老爷岭南部狍冬季移动、卧息生境选择及其适宜性评价

在动物生境研究中,移动生境和卧息生境是生境研究的焦点。开展移动生境和卧息生境选择,并在此基础上进行生境评价,有利于深入了解动物对移动和卧息生境条件的需求,制定科学合理的栖息地保护计划。以东北虎（Panthera tigris altaica）的主要猎物物种之一-狍（Capreolus pygargus）为研究对象,于2017-2019年冬季积雪覆盖期在老爷岭南部通过随机布设28个大样方和84条用于足迹链跟踪的样线收集狍的移动点和卧息点信息,再结合近年来收集的东北虎出现点,利用广义可加模型（GAM）和最大熵模型（MaxEnt）进行狍移动、卧息生境选择及评价研究。移动生境选择研究表明,狍在移动的过程中偏好选择坡度小、距农田距离>500 m、远离道路、居民点和低海拔或较高海拔的区域;移动生境评价分析表明,移动适宜和次适宜生境面积之和为1318.16 km²,占研究区域面积的51.28%,当加入虎活动点影响因子后,狍移动适宜和次适宜生境面积之和为901.52 km²,适宜和次适宜生境面积之和减少了31.61%。狍卧息生境选择研究表明,水源、农田、道路和雪深是影响狍卧息的关键因素,其中雪深对狍卧息生境选择的贡献率达到70.13%;卧息生境评价表明,卧息适宜和次适宜生境面积之和为1243.77 km²,占研究区域面积的48.39%,当加入虎出现点因子后,适宜生境和次适宜生境面积之和减少了61.00%,仅为485.02 km²。研究认为,虎的出现对狍移动和卧息生境选择均产生影响,虎的活动及捕食行为可能会减少狍的活动范围和频次,狍远离虎活动区域卧息休息,压缩了狍适宜卧息的空间。     

Concurrent habitat and life history influences on effective/census population size ratios in stream-dwelling trout

Lower effective sizes (N(e)) than census sizes (N) are routinely documented in natural populations, but knowledge of how multiple factors interact to lower N(e)/N ratios is often limited. We show how combined habitat and life-history influences drive a 2.4- to 6.1-fold difference in N(e)/N ratios between two pristine brook trout (Salvelinus fontinalis) populations occupying streams separated by only 750 m. Local habitat features, particularly drainage area and stream depth, govern trout biomass produced in each stream. They also generate higher trout densities in the shallower stream by favoring smaller body size and earlier age-at-maturity. The combination of higher densities and reduced breeding site availability in the shallower stream likely leads to more competition among breeding trout, which results in greater variance in individual reproductive success and a greater reduction in N(e) relative to N. A similar disparity between juvenile or adult densities and breeding habitat availability is reported for other species and hence may also result in divergent N(e)/N ratios elsewhere. These divergent N(e)/N ratios between adjacent populations are also an instructive reminder for species conservation programs that genetic and demographic parameters may differ dramatically within species.     

Selection for biennial life histories in plants

The applicability of traditional models of life-history evolution is restricted because models assume constant environments without density-dependence. In these models the geometric growth rate () of a lineage is the natural choice for the fitness criterion. Because in growing populations is very sensitive to changes in generation time, biennials appear at a disadvantage when compared to species with annual reproduction. We propose an alternative fitness criterion for the situation in which recruitment is limited by both the availability of seeds and the (constant) rate at which safe sites for establishment are created by small-scale disturbances. Under the assumptions of the model the evolutionarily stable strategy is to maximize expected seed production, irrespective of the length of the life cycle. For monocarpic plants, this implies that delay of flowering is favourable if the increased seed production compensates for the death of rosettes.Publication of the Meijendel comité, New series No. 89.Nomenclature follows Heukels & van der Meijden (1983), Flora van Nederland, Wolters Noordhoff, Groningen.We would like to thank Prof. K. Bakker, Dr Nora Croin Michielsen, Dr E. van der Meijden and Dr M. Sabelis for their comments on a number of previous drafts. We are indebted to the Netherlands Foundation for Fundamental Research (B.I.O.N.) and to the Netherlands Organization for the Advancement of Pure Research (Z.W.O.) for research grants to T. J. de Jong and P. G. L. Klinkhamer, and to J. A. J. Metz, respectively.     

Population size, distribution and habitat selection of the white-tailed eagle Haliaeetus albicilla in the alluvial wetlands of Croatia

From 2003–2006, research on the breeding distribution of the white-tailed eagle (Haliaeetus albicilla) was conducted in Croatia in order to assess the size of the national population. In 125 locations, clear signs of breeding activity were found. An additional 10 presumably active territories were detected but it was not possible to locate the exact position of the nests and confirm the breeding. Based on this, it is concluded that the national breeding population is not less than 135 breeding pairs. The present distribution can be compared with previous reports with the exception of the area along the Ilova and Lonja rivers that have never been reported as an important breeding site. Analysis of the characteristics of 138 nest positions as well as preferences/avoidance of specific structural features were performed. The results showed that white-tailed eagles prefer to build their nests on pedunculate oaks, narrow-leafed ash and white poplars with the greatest preference for mature trees with a diameter above 92.5 cm. The minimal distance between two active pairs was 348 meters. More than 50% of the national population breed less than two km from a large water area and 95% of the population less than four km. More than 95% of the population breed at altitudes lower than 140 m above sea level and are further than one km away from the nearest human settlement, regardless of the availability of forests. According to several parameters (distance to a large water area, elevation, forest presence, distance to the nearest settlement, distance to highways and railways) geographic information system (GIS) helped to determine potential white-tailed eagle breeding areas.     

Aspects of habitat selection in the mosquitofish gambusia affinis

Laboratory experiments were performed to determine behavioral preferences of Gambusia affinis for habitat variables in partitioned aquaria. The fish preferred calm water, dark-colored substrates and subsurface vegetation providing lateral concealment. Floating cover, which obstructed access to the surface, was avoided. Lack of preference for real over plastic plant cover indicates that visual rather than chemical cues are involved. These laboratory preferences correspond to the reported microhabitat distribution of G. affinis in nature and indicate the presence of an active habitat preference, as opposed to passive habitat correlation, in this species. Species-specific habitat preferences, which may be narrower where a species occurs sympatrically with its congeners, probably form part of a reproductive isolating mechanism.     

Adaptation and habitat selection in the eco-evolutionary process

The struggle for existence occurs through the vital rates of population growth. This basic fact demonstrates the tight connection between ecology and evolution that defines the emerging field of eco-evolutionary dynamics. An effective synthesis of the interdependencies between ecology and evolution is grounded in six principles. The mechanics of evolution specifies the origin and rules governing traits and evolutionary strategies. Traits and evolutionary strategies achieve their selective value through their functional relationships with fitness. Function depends on the underlying structure of variation and the temporal, spatial and organizational scales of evolution. An understanding of how changes in traits and strategies occur requires conjoining ecological and evolutionary dynamics. Adaptation merges these five pillars to achieve a comprehensive understanding of ecological and evolutionary change. I demonstrate the value of this world-view with reference to the theory and practice of habitat selection. The theory allows us to assess evolutionarily stable strategies and states of habitat selection, and to draw the adaptive landscapes for habitat-selecting species. The landscapes can then be used to forecast future evolution under a variety of climate change and other scenarios.     

Ontogenetic shifts in habitat use by the endangered Roanoke logperch (Percina rex)

1. Conservation of the federally endangered Roanoke logperch (Percina rex, Jordan and Evermann) necessitates protection of habitat that is critical for all age classes. We examined habitat use patterns of individual logperch to determine: (1) if age classes of logperch in the Nottoway and Roanoke Rivers exhibit habitat selectivity, (2) if age classes differ in habitat use, and (3) if ontogenetic patterns of habitat use differ between the Roanoke and Nottoway river populations. 2. In the summers of 2000 and 2001, we observed 17 young‐of‐year (YOY) logperch [<4 cm total length (TL)], 13 subadult logperch (4–8 cm TL), and 49 adult logperch (>8 cm TL) in the upper Roanoke River, and 40 subadult and 39 adult logperch in the Nottoway River, Virginia. 3. All size classes of Roanoke logperch demonstrated habitat selectivity and logperch used a wide range of habitats in the Roanoke and Nottoway rivers during ontogeny. Habitat use by logperch varied among age classes and between rivers. 4. In the Roanoke River, adult and subadult logperch primarily preferred run and riffle habitat, often over gravel substrate. Subadults were found in lower water velocities and slightly more embedded microhabitats than adults. YOY logperch were found in shallow, stagnant backwaters and secondary channels. In the Nottoway River, both adult and subadult logperch were found over sand and gravel in deep, low‐velocity pools and runs. Subadults were observed in slightly more silted, lower velocity habitat than adults. Shifts in habitat use were more distinct between age classes in the Roanoke River than the Nottoway River. 5. Successful conservation of this species will involve sound understanding of spatial variation in habitat use over logperch life history and preservation of the ecological processes that preserve required habitat mosaics.     

Coexistence of white-footed mice and deer mice may be mediated by fluctuating environmental conditions

White-footed mice, Peromyscus leucopus noveboracensis, and deer mice, P. maniculatus nubiterrae, occur sympatically throughout much of the Appalachian Mountains of the eastern United States. Previous studies have shown that these two species are behaviorally and ecologically similar and do not partition food or microhabitat. In this paper I use a 14-year data set to demonstrate that the two species have differential population growth and survival rates in response to food abundance and season, which may mediate their coexistence. The ratio of white-footed mice to deer mice ranged from 0.5:1 to 6:1. During summer and times of tood abundance, white-footed mice gained a numerical advantage over deer mice in 10 of 14 years, whereas following winter and poor food production, deer mice had higher survival in 9 of 13 years. The major decline in white-foote mice, but not deer mice, was associated with poor mast (acorn) production in autumn. Differential survival of deer mice may be due to their physiological adaptations to cold temperature and efficient use of torpor during food shortage. Inter-year variance in food production and climatic conditions appear to change the competitive advantage of each species often enough to permit coexistence. Coexistence of these two ecologically similar species may be maintained by different physiological limitations in a fluctuating environment.     

官山自然保护区白颈长尾雉季节性生境选择

2009年10月至2010年11月,2015年7月至11月在江西官山自然保护区对白颈长尾雉不同生活史阶段的(繁殖期、育雏期、繁殖后期)生境选择进行了比较研究。调查了6条样线上的126个样方,选取与其生境相关的17个因子进行了观察与测量。研究结果表明,不同生活史阶段各生境选择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,即生境选择的主要生态因子随生活史阶段而变化。卡方检验及单因素方差分析,结果显示,各生活史阶段,白颈长尾雉对林型、坡向、坡度、灌木高度、草本高度和水源距离6个生态因子上无显著差异(P≥0.05),其余11个生态因子两两之间存在显著差异或极显著差异。典则判别结果显示,白颈长尾雉在不同生活史阶段在生境选择上存在一定程度的重叠,又有较为明显的差异。逐步判别表明,在不同生活史阶段,白颈长尾雉生境选择差异上有一系列的生态因子发挥作用,依照贡献值的大小依次为草本数量、落叶层盖度、乔木盖度、海拔和乔木数量,由这5个变量构成的方程对生境选择差异的正确区分率为80.3%。繁殖期和越冬期食物条件是影响白颈长尾雉生境选择的主要因素,而育雏期则为隐蔽条件。     

The cost of habitat selection in prairie voles: an empirical assessment using isodar analysis

The ideal free distribution assumes that habitat selection is without cost and predicts that fitness should be equal in different habitats. If habitat selection has a cost, then individuals should only move to another habitat when potential fitness in the new habitat exceeds that in the source habitat by an amount greater than the cost of habitat selection. We used isodar techniques to assess the cost of habitat selection. In an experimental landscape, we monitored density, movement, and reproductive success of adult female prairie voles, Microtus ochrogaster, in adjacent paired habitats with low and high cover. We tested the following hypotheses: (1) adult female prairie voles exhibited density-dependent habitat selection; (2) the cost of habitat selection was density-independent. Habitat quality based on population density and fitness of adult females was higher in high cover habitats. Net movement was from low cover to high cover habitats. The results indicated that adult female prairie voles exhibited density-dependent habitat selection. Furthermore, there was a significant cost of habitat selection, and the cost was density-independent.     

Life history strategies and habitat templets of tropical butterflies in north-eastern Australia

Three multivoltine species of satyrine butterflies in the genus Mycalesis (Lepidoptera: Nymphalidae) are narrowly sympatric in the wet–dry tropics of north-eastern Australia. They show a range of ecological strategies and adaptations associated with contrasting habitats and varying selective pressures. Two abiotic factors, namely favorability (the reciprocal of seasonal adversity) and predictability (broadly the reciprocal of disturbance), were examined as potential environmental selective forces in shaping their life histories. Comparison of several key life history traits of the wet-season form revealed that the life histories of each species corresponded well with their habitat characteristics. M. perseus, which lives in habitats which are less favorable (i.e. adverse) and more unpredictable (i.e. temporary), shows many traits of an r-type strategy: smaller size, faster development, earlier maturation, higher fecundity, smaller egg size, and rapid population increase. By contrast, M. sirius and M. terminus, which live in more favorable and predictable (i.e. permanent) habitats, have many life history attributes and other characteristics in common which link them closer to K-type strategies. The only discrepancy is lower potential reproductive effort of M. perseus, which may be accounted for in terms of an evolutionary trade-off, such as with dispersal or dormancy. Other correlates associated with the M. perseus life history tactic include higher sex-size dimorphism, greater dispersal ability, better tolerance to adverse conditions, stronger phenotypic variation, greater degree of polyandry, and a more flexible breeding strategy. The life history patterns of these species are discussed in the context of evolutionary life history models, particularly the Southwood–Greenslade habitat templet.