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Space-based tracking technology using low-cost miniature tags is now delivering data on fine-scale animal movement at near-global scale. Linked with remotely sensed environmental data, this offers a biological lens on habitat integrity and connectivity for conservation and human health; a global network of animal sentinels of environmental change. Publisher PDF

Quantifying movement and demographic events of free-ranging animals is fundamental to studying their ecology, evolution and conservation. Technological advances have led to an explosion in sensor-based methods for remotely observing these phenomena. This transition to big data creates new challenges for data management, analysis and collaboration. We present the Movebank ecosystem of tools used by thousands of researchers to collect, manage, share, visualize, analyse and archive their animal tracking and other animal-borne sensor data. Users add sensor data through file uploads or live data streams and further organize and complete quality control within the Movebank system. All data are harmonized to a data model and vocabulary. The public can discover, view and download data for which they have been given access to through the website, the Animal Tracker mobile app or by API. Advanced analysis tools are available through the EnvDATA System, the MoveApps platform and a variety of user-developed applications. Data owners can share studies with select users or the public, with options for embargos, licenses and formal archiving in a data repository. Movebank is used by over 3,100 data owners globally, who manage over 6 billion animal location and sensor measurements across more than 6,500 studies, with thousands of active tags sending over 3 million new data records daily. These data underlie >700 published papers and reports. We present a case study demonstrating the use of Movebank to assess life-history events and demography, and engage with citizen scientists to identify mortalities and causes of death for a migratory bird. A growing number of researchers, government agencies and conservation organizations use Movebank to manage research and conservation projects and to meet legislative requirements. The combination of historic and new data with collaboration tools enables broad comparative analyses and data acquisition and mapping efforts. Movebank offers an integrated system for real-time monitoring of animals at a global scale and represents a digital museum of animal movement and behaviour. Resources and coordination across countries and organizations are needed to ensure that these data, including those that cannot be made public, remain accessible to future generations. published

According to migration theory and several empirical studies, long-distance migrants are more time-limited during spring migration and should therefore migrate faster in spring than in autumn. Competition for the best breeding sites is supposed to be the main driver, but timing of migration is often also influenced by environmental factors such as food availability and wind conditions. Using GPS tags, we tracked 65 greater white-fronted geese Anser albifrons migrating between western Europe and the Russian Arctic during spring and autumn migration over six different years. Contrary to theory, our birds took considerably longer for spring migration (83 days) than autumn migration (42 days). This difference in duration was mainly determined by time spent at stopovers. Timing and space use during migration suggest that the birds were using different strategies in the two seasons: In spring they spread out in a wide front to acquire extra energy stores in many successive stopover sites (to fuel capital breeding), which is in accordance with previous results that white-fronted geese follow the green wave of spring growth. In autumn they filled up their stores close to the breeding grounds and waited for supportive wind conditions to quickly move to their wintering grounds. Selection for supportive winds was stronger in autumn, when general wind conditions were less favourable than in spring, leading to similar flight speeds in the two seasons. In combination with less stopover time in autumn this led to faster autumn than spring migration. White-fronted geese thus differ from theory that spring migration is faster than autumn migration. We expect our findings of different decision rules between the two migratory seasons to apply more generally, in particular in large birds in which capital breeding is common, and in birds that meet other environmental conditions along their migration route in autumn than in spring. published

Volant organisms are adapted to atmospheric patterns and processes. Understanding the lives of animals that inhabit this aerial environment requires a detailed investigation of both the animal’s behavior and its environmental context—i.e., the environment that it encounters at a range of spatial and temporal scales. For aerofauna, it has been relatively difficult to observe the environment they encounter while they move. Large international efforts using satellite and weather model reanalysis now provide some of the environmental data on atmospheric environments throughout the globe. Track annotation—the approach of merging the environmental data with the movement track measured via telemetry—can be conducted automatically using online tools such as Movebank-Env-DATA or RNCEP. New parameterization approaches can use environmentally annotated tracks to approximate specific atmospheric conditions, such as uplift and tail wind, which are not typically observed at the exact locations of the movement, but are critical to movement. Reducing the complexity of movement to single-dimensional characteristic (such as flight speed, elevation, etc.) and defining the temporal scope of the movement phenomenon in the focus of the analysis (seasonal, daily, minutely, etc.) makes it possible to construct empirical models that explain the movement characteristic as driven by the environmental conditions during flight, despite the highly dynamic, complex, and scale-dependent structures of both the flight path and atmospheric variables. This chapter will provide several examples for such empirical movement models from different species of birds and using several resources for atmospheric data.

1. The Argos System is used worldwide to satellite-track free-ranging animals, but location errors can range from tens of metres to hundreds of kilometres. Low-quality locations (Argos classes A, 0, B and Z) dominate animal tracking data. Standard-quality animal tracking locations (Argos classes 3, 2 and 1) have larger errors than those reported in Argos manuals.2. The Douglas Argos-filter (DAF) algorithm flags implausible locations based on user-defined thresholds that allow the algorithm's performance to be tuned to species' movement behaviours and study objectives. The algorithm is available in Movebank – a free online infrastructure for storing, managing, sharing and analysing animal movement data.3. We compared 21,044 temporally paired global positioning system (GPS) locations with Argos location estimates collected from Argos transmitters on free-ranging waterfowl and condors (13 species, 314 individuals, 54,895 animal-tracking days). The 95th error percentiles for unfiltered Argos locations 0, A, B and Z were within 35·8, 59·6, 163·2 and 220·2 km of the true location, respectively. After applying DAF with liberal thresholds, roughly 20% of the class 0 and A locations and 45% of the class B and Z locations were excluded, and the 95th error percentiles were reduced to 17·2, 15·0, 20·9 and 18·6 km for classes 0, A, B and Z, respectively. As thresholds were applied more conservatively, fewer locations were retained, but they possessed higher overall accuracy.4. Douglas Argos-filter can improve data accuracy by 50–90% and is an effective and flexible tool for preparing Argos data for direct biological interpretation or subsequent modelling. published

Birds migrate over vast distances at substantial costs. The highly dynamic nature of the air makes the selection of the best travel route difficult. We investigated to what extent migratory birds may optimise migratory route choice with respect to wind, and if route choice can be subject to natural selection. Following the optimal route, calculated using 21 years of empirical global wind data, reduced median travel time by 26.5% compared to the spatially shortest route. When we used a time-dependent survival model to quantify the adaptive benefit of choosing a fixed wind-optimised route, 84.8% of pairs of locations yielded a route with a higher survival than the shortest route. This suggests that birds, even if incapable of predicting wind individually, could adjust their migratory routes at a population level. As a consequence, this may result in the emergence of low-cost flyways representing a global network of aerial migratory pathways. published

We present a karyotypic survey of the European freshwater planarian Dugesia polychroa, detailing frequencies of diploid and polyploid forms from 35 localities in seven countries. In this hermaphroditic species, diploids reproduce sexually and polyploids by pseudogamous parthenogenesis. Previous laboratory studies have shown that the two reproductive modes can interbreed, which may lead to new tri-, tetra-, and pentaploid lineages. We found four pure sexual, 25 pure parthenogenetic, and six mixed populations. Although some polyploid populations consisted entirely of triploids, most contained triploid and tetraploid individuals. Pentaploids were rare and reported for the first time from the field. In most populations, the higher ploidy levels were represented by fewer individuals. Our results indicate that occasional fertilisation of parthenogenetic eggs leading to genome addition is responsible for the maintainance of polyploid forms in natural populations of D. polychroa.

Theoretical models on the costs and benefits of sexual reproduction usually assume that sexual and parthenogenetic individuals coexist and are identical, except for their mode of reproduction. Empirical studies, however, show that conspecific sexuals and parthenogens can differ in ecological preferences and geographical distribution, which complicates the investigation of the costs and benefits of sex. The freshwater planarian Schmidtea polychroa exists in a sexual and a sperm-dependent, parthenogenetic form. The latter produce fertile sperm and mate, but received sperm is used only to induce parthenogenetic embryo development. We compared the spatial and ecological distribution between forms within a lake from which both had been reported. Forty samples showed large differences in the relative frequencies of sexuals and parthenogens. Nineteen samples contained both biotypes. All but one of the 13 ecological parameters that we measured, could not explain a significant part of the variance in relative abundance of each type. Only leech abundance had a significant, negative effect on the presence of sexual individuals. The causes of this effect remained unclear. We also estimated the amount of genetic isolation between sites and between reproductive modes, using body coloration as a genetic marker. Large differences were found between sites, suggesting isolation of local populations by migration barriers. There were smaller differences between sexuals and parthenogens within sites, suggesting that genetic exchange between biotypes may be limited. We conclude that there appears to be weak niche differentiation between sexuals and parthenogens in Lago di Caldonazzo in late summer. Fluctuations in relative frequency appears to be a consequence of low dispersal between local populations and stochastic effects within them.

Background Understanding how environmental conditions, especially wind, influence birds' flight speeds is a prerequisite for understanding many important aspects of bird flight, including optimal migration strategies, navigation, and compensation for wind drift. Recent developments in tracking technology and the increased availability of data on large-scale weather patterns have made it possible to use path annotation to link the location of animals to environmental conditions such as wind speed and direction. However, there are various measures available for describing not only wind conditions but also the bird's flight direction and ground speed, and it is unclear which is best for determining the amount of wind support (the length of the wind vector in a bird’s flight direction) and the influence of cross-winds (the length of the wind vector perpendicular to a bird’s direction) throughout a bird's journey. Results We compared relationships between cross-wind, wind support and bird movements, using path annotation derived from two different global weather reanalysis datasets and three different measures of direction and speed calculation for 288 individuals of nine bird species. Wind was a strong predictor of bird ground speed, explaining 10-66% of the variance, depending on species. Models using data from different weather sources gave qualitatively similar results; however, determining flight direction and speed from successive locations, even at short (15 min intervals), was inferior to using instantaneous GPS-based measures of speed and direction. Use of successive location data significantly underestimated the birds' ground and airspeed, and also resulted in mistaken associations between cross-winds, wind support, and their interactive effects, in relation to the birds' onward flight. Conclusions Wind has strong effects on bird flight, and combining GPS technology with path annotation of weather variables allows us to quantify these effects for understanding flight behaviour. The potentially strong influence of scaling effects must be considered and implemented in developing sampling regimes and data analysis. Electronic supplementary material The online version of this article (doi:10.1186/2051-3933-1-4) contains supplementary material, which is available to authorized users.

Soaring raptors can fly at high altitudes of up to 9000 m. The behavioural adjustments to high-altitude flights are largely unknown. We studied thermalling flights of Himalayan vultures (Gyps himalayensis) from 50 to 6500 m above sea level, a twofold range of air densities. To create the necessary lift to support the same weight and maintain soaring flight in thin air birds might modify lift coefficient by biophysical changes, such as wing posture and increasing the power expenditure. Alternatively, they can change their flight characteristics. We show that vultures use the latter and increase circle radius by 35% and airspeed by 21% over their flight altitude range. These simple behavioural adjustments enable vultures to move seamlessly during their annual migrations over the Himalaya without increasing energy output for flight at high elevations.

Background The movement of animals is strongly influenced by external factors in their surrounding environment such as weather, habitat types, and human land use. With advances in positioning and sensor technologies, it is now possible to capture animal locations at high spatial and temporal granularities. Likewise, scientists have an increasing access to large volumes of environmental data. Environmental data are heterogeneous in source and format, and are usually obtained at different spatiotemporal scales than movement data. Indeed, there remain scientific and technical challenges in developing linkages between the growing collections of animal movement data and the large repositories of heterogeneous remote sensing observations, as well as in the developments of new statistical and computational methods for the analysis of movement in its environmental context. These challenges include retrieval, indexing, efficient storage, data integration, and analytical techniques. Results This paper contributes to movement ecology research by presenting a new publicly available system, Environmental-Data Automated Track Annotation (Env-DATA), that automates annotation of movement trajectories with ambient atmospheric observations and underlying landscape information. Env-DATA provides a free and easy-to-use platform that eliminates technical difficulties of the annotation processes and relieves end users of a ton of tedious and time-consuming tasks associated with annotation, including data acquisition, data transformation and integration, resampling, and interpolation. The system is illustrated with a case study of Galapagos Albatross (Phoebastria irrorata) tracks and their relationship to wind, ocean productivity and chlorophyll concentration. Our case study illustrates why adult albatrosses make long-range trips to preferred, productive areas and how wind assistance facilitates their return flights while their outbound flights are hampered by head winds. Conclusions The new Env-DATA system enhances Movebank, an open portal of animal tracking data, by automating access to environmental variables from global remote sensing, weather, and ecosystem products from open web resources. The system provides several interpolation methods from the native grid resolution and structure to a global regular grid linked with the movement tracks in space and time. The aim is to facilitate new understanding and predictive capabilities of spatiotemporal patterns of animal movement in response to dynamic and changing environments from local to global scales. Electronic supplementary material The online version of this article (doi:10.1186/2051-3933-1-3) contains supplementary material, which is available to authorized users.

Variation is key to the adaptability of species and their ability to survive changes to the Earth's climate and habitats. Plasticity in movement strategies allows a species to better track spatial dynamics of habitat quality. We describe the mechanisms that shape the movement of a long-distance migrant bird (turkey vulture, Cathartes aura ) across two continents using satellite tracking coupled with remote-sensing science. Using nearly 10 years of data from 24 satellite-tracked vultures in four distinct populations, we describe an enormous amount of variation in their movement patterns. We related vulture movement to environmental conditions and found important correlations explaining how far they need to move to find food (indexed by the Normalized Difference Vegetation Index) and how fast they can move based on the prevalence of thermals and temperature. We conclude that the extensive variability in the movement ecology of turkey vultures, facilitated by their energetically efficient thermal soaring, suggests that this species is likely to do well across periods of modest climate change. The large scale and sample sizes needed for such analysis in a widespread migrant emphasizes the need for integrated and collaborative efforts to obtain tracking data and for policies, tools and open datasets to encourage such collaborations and data sharing.

Parthenogenetic lineages that arise in a hermaphroditic, sexual population will inherit the male function from their sexual progenitors. Natural selection then acts to reduce male allocation of the parthenogens, freeing resources presumably for the female function. Depending on age and the available genetic variation, one therefore expects to find reduced male allocation in naturally occurring parthenogenetic lineages. We investigated the allocation to sperm production in the hermaphroditic flatworm Dugesia polychroa in three lakes containing a sexual (S), a (pseudogamous) parthenogenetic (P), and a mixed sexual-parthenogenetic population (M). Parthenogenetic lineages from M were assumed to be relatively young due to recurrent origins from the coexisting sexuals, whereas those from P were assumed to be older on biogeographical grounds. As predicted, we found drastically reduced sperm production in parthenogens compared to sexuals, even in the parthenogenetic lineages from M, which may be younger. M parthenogens did not have more testes, but produced more sperm than individuals from the purely parthenogenetic population (P). However, the latter result could not be reproduced with laboratory-raised animals and therefore may be a consequence of different ecological conditions in the different lakes, for example, differences in mating rates. To study the behavioral component of male allocation, copulation frequencies were recorded for sexuals from M and for parthenogens from P. Compared to the drastic reduction in sperm production, copulation frequency was less reduced in parthenogens. This may be a consequence of allosperm limitation in pseudogamous parthenogenetic populations.

In hermaphrodites, the cost of sexuality can favor the spread of parthenogenesis in two ways. First, it can promote higher female fecundity in parthenogens that have reduced allocation to the male function. Second, if parthenogens have retained a fertile male function, they can spread genes for parthenogenesis into a coexisting sexual population. We present evidence for both effects in a natural population of the flatworm Schmidtea polychroa. Parthenogens, which have a reduced male function, had 42% higher female fecundity than coexisting sexuals. New, presumably parthenogenetic, triploids arose out of the diploid sexual population at a frequency of 1.3%, probably as a result of gene flow from parthenogens to sexuals. However, we could also identify a strong compensating fitness benefit for sexuals: they had substantially higher female fertility than coexisting parthenogens, both in terms of cocoon fertility (93% and 74% respectively) and offspring per fertile cocoon (3.6 and 2.8 respectively). Additional key words: evolution of sex, sex allocation, Platyhelminthes, Dugesia, Schmidtea Evolutionary theory predicts that strong counteracting selective forces act on sexual and parthenogenetic reproduction. On the one hand, it is widely accepted that sex pays the high "cost of male allocation" (Maynard Smith 1978) or "cost of meiosis" (Williams 1975). On the other hand, benefits of sexual reproduction have been postulated such as advantages in hostparasite coevolution, reduced accumulation of mutations, reduced competition among sexuals, and the opportunity to repair physical DNA damage (Bell 1982; Vrijenhoek 1984; Stearns 1987; Kondrashov 1988; Michod & Levin 1988; Weeks 1993). Some predictions of these theories have been the focus of experimental studies (Lively 1987; Mogie & Ford 1988; Michaels & Bazzaz 1989; Hamilton et al. 1990; Lively et al. 1990; Moritz et al. 1991; Vrijenhoek 1994), but relatively little effort has been put into quantifying the costs and benefits of sex. The only available field estimate of the benefit of sex is the 1.43-fold higher fitness of sexually derived offspring that was found in an experimental study of the grass Anthoxanthum odoratum (Kelley et al. 1988). Estimating the cost of sex in hermaphrodites is not as easy as in outcrossing gonochoristic species, and has been the subject of several theoretical studies (Charlesworth 1980; Lloyd 1988; Joshi & Moody a Author for correspondence. Present address: Institut fiir Spezielle Zoologie, University of Muenster, Huefferstrasse 1, D-48149 Muenster, Germany. E-mail: michiels @ uni-muenster.de 1995). Briefly summarized, it depends on the sex allocation of the coexisting sexual and parthenogenetic hermaphrodites, as well as on the ability of the male function of the parthenogens to generate parthenogenetic offspring in sexual partners. If the latter is not possible, the male function of a parthenogen is effectively "sterile" for the parthenogenetic sub-population, as it makes no contribution to the next generation of parthenogens. Selfing rate and inbreeding depression are also important, but not relevant for our model system and are therefore not mentioned here. Let us first consider a newly arisen parthenogenetic lineage with the same sex allocation as its sexual ancestor, but with a sterile male function (e.g., parthenogens are polyploid and so are their sperm). Such individuals will produce the same number of maternal offspring and make the same genetic contribution to the next generation as sexuals. Hence, the cost of sex is zero and additional changes are needed to offer an advantage to parthenogenetic hermaphrodites (see also Mogie 1996). On the one hand, parthenogens may reduce male allocation rparth and increase female allocation (1-rparth). Only when rse=0.5 in the sexual ancestor, and by complete elimination of the male function in parthenogens, can the latter obtain a 2-fold advantage. In all other cases (rsex O), the cost of sex [1/(1-rsex)] will be less than 2-fold. On the other hand, parthenogenetic hermaphrodites may generate new parthenogenetic lineages by fatherThis content downloaded from 157.55.39.45 on Thu, 01 Sep 2016 04:44:16 UTC All use subject to http://about.jstor.org/terms Weinzierl, Schmidt, & Michiels ing eggs of sexual partners. Assuming a simple genetic system, and all else being equal between sexuals and parthenogens, this will result in a (maximum) 3/2 advantage for parthenogens (Charlesworth 1980). This advantage will be lower when some partners of parthenogens are not sexual, but parthenogenetic as in sperm-dependent parthenogens (Beukeboom & Vrijenhoek 1998). Loss of eggs and sperm from sexuals to parthenogenetic partners should also be included in the cost of sex. Hence, in order to reveal the cost of sex in a natural population of hermaphrodites one has to consider (1) reallocation of resources to the female function in parthenogens and (2) the production of parthenogenetic offspring through gene flow from parthenogens to sexuals. Many examples of reduced male function in parthenogenetic hermaphrodites are known (Christensen et al. 1978; Nogler 1984; 0 Foighil & Eernisse 1988; 0 Foighil & Thiriot-Quievereux 1991; Weinzierl et al. 1998), but the reduction has never been shown to lead to a substantial increase in female reproductive success. This may be explained by the fact that male allocation is low in some sexual hermaphrodites (Bell 1984a,b). Yet, it is clearly high in others (e.g., Rameau & Gouyon 1991). Gene flow from parthenogens to sexuals is possible in a number of hermaphrodites (Suomalainen et al. 1987; Asker & Jerling 1992) and can result in new parthenogenetic lineages (Menken et al. 1995). The hermaphroditic freshwater planarian Schmidtea polychroa BALL (=Dugesia polychroa (SCHMIDT); Tricladida, Paludicola) consists of a diploid sexual and several polyploid parthenogenetic biotypes (Benazzi 1957). Individuals of both modes produce cocoons that contain 1-10 eggs embedded in a common yolk mass. Parthenogenetic reproduction is pseudogamous, i.e., egg development is stimulated by a sperm cell that does not contribute genetically (Benazzi 1950; Benazzi & Benazzi Lentati 1976; Beukeboom & Vrijenhoek 1998). Despite being polyploid, parthenogenetic animals have functional, haploid sperm (Benazzi Lentati 1970), but, like sexuals, always need allosperm from a sexual or parthenogenetic partner in order to produce maternal offspring (Benazzi & Benazzi Lentati 1992). Parthenogens mate frequently, with each other and with sexuals (Peters et al. 1996; M. Storhas, pers. comm.). In S. polychroa, as in other planarians (Hyman 1951), testes in sexual individuals are numerous and occupy significant portions of the body. Parthenogens of S. polychroa, in contrast, have very few testes (Weinzierl et al. 1998). Parthenogenetic worms also appear to have a lower mating rate than sexuals (Weinzierl et al. 1998), which again saves resources that can be reallocated to the female function. We tested whether parthenogens of S. polychroa have higher female fecundity than their coexisting sexual conspecifics. Flexible reallocation is likely in planarians, because they are known to adjust cocoon production in response to fluctuating resource availability (Reynoldson 1964, 1977; Reynoldson & Young 1965; Boddington & Mettrick 1977; Calow & Woolhead 1977). By fertilizing sexual eggs, parthenogens of S. polychroa can "inject" genes for parthenogenesis into the coexisting sexual population, and this can generate new parthenogenetic lineages in laboratory crosses (Benazzi Lentati 1966). We investigated whether sexual individuals taken directly from our study population produced parthenogens among their offspring. One balancing selective force favoring sexual reproduction is female fertility, which is known to be reduced in a number of parthenogenetic insects (Lamb & Willey 1979). We compared fertility of cocoons produced by sexual and parthenogenetic worms.