Differences In Movement Rates Research Articles

Seasonality in daily movement patterns of mandrills revealed by combining direct tracking and camera traps.

Movement is a fundamental characteristic of animals, but challenging to measure noninvasively. Noninvasive methods for measuring travel have different weaknesses, so multiple techniques need to be applied multiple techniques for reliable inferences. We used two methods, direct tracking and camera trapping, to examine the variation in time and seasonal differences in movement rates of mandrills (Mandrillus sphinx), an elusive primate that lives in large groups in central Africa. In a 400-km2 rainforest area in Moukalaba-Doudou National Park, Gabon, we tracked unidentified groups 46 times from 2009 to 2013. We systematically placed 157 terrestrial camera traps in the same area from 2012 to 2014 and recorded groups 309 times. Generalized additive mixed models (GAMMs) of the tracking data indicated that the group travel speed varied with time and season. In the fruiting season, the movement rate fluctuated with time in a bimodal pattern, whereas in the nonfruiting season, it increased monotonously with time. The predicted day range was longer in the fruiting season (6.98 km) than in the nonfruiting season (6.06 km). These seasonal differences suggest responses to changes in food resources and temperature. Camera-trap detection rates showed similar temporal and seasonal patterns to the tracking data, allowing us to generalize our findings to the population level. Moreover, cameras never detected mandrills at night, and we observed that they slept high in trees and hardly moved until the next morning, all suggesting their strict avoidance of nighttime movement. This study demonstrated the significance of the multiple-method approach in drawing robust conclusions on temporal patterns of animal movement.

Resource selection of mule deer in a shrub‐steppe ecosystem: influence of woodland distribution and animal behavior

AbstractUngulates inhabiting arid ecosystems are reliant on productive forb and shrub communities during summer months to meet nutritional demands for survival and reproduction. In the western United States, expansion of woodland vegetation into shrub‐dominated communities and the potential loss of habitat are of concern with regard to animal populations reliant on robust sagebrush shrub and forb vegetation. We used mixed‐effects logistic regression to model resource selection of female mule deer (Odocoileus hemionus) during the summers of 2005–2008. We considered selection at two spatial scales, and during three daily activity periods (night, crepuscular, and mid‐day) corresponding to resting and foraging. We evaluated habitat variables related to vegetation type, site productivity, terrain attributes, and fine‐scale abundance of pinyon–juniper cover. Those attributes allowed us to account for variation in site productivity and animal behaviors that could obscure the true relationship between density of pinyon–juniper woodland and habitat use by mule deer. We detected observable differences in habitat use by mule deer among the three activity periods with significant differences in movement rates. Deer were most active during crepuscular periods corresponding with foraging activity, and least active mid‐day when temperatures were highest. Summer habitat consisted of sites with high potential productivity, greater shrub abundance, and greater proximity to riparian areas. Deer avoided high levels of tree cover (>40% coverage) at all spatial and temporal scales, and in general selection declined with increasing pinyon–juniper cover, particularly during foraging periods. Nonetheless, mule deer selected areas with low to intermediate tree cover (10% to 40%) during resting periods and avoided areas of productive shrub and forb vegetation and riparian areas, when surrounded by denser stands of pinyon–juniper cover. These results emphasize the importance of productive shrub and forb vegetation to mule deer inhabiting semi‐arid regions and suggest that low levels of tree cover are beneficial, especially during resting periods. Nevertheless, dense pinyon–juniper cover was generally avoided even in areas of high site productivity. These relationships lend support to the concern that increases in large, dense stands of pinyon–juniper reduce availability of summer habitat and alter patterns of resource selection for mule deer, a shrub‐dependent ungulate.

Integrating the influence of weather into mechanistic models of butterfly movement

BackgroundUnderstanding the factors influencing movement is essential to forecasting species persistence in a changing environment. Movement is often studied using mechanistic models, extrapolating short-term observations of individuals to longer-term predictions, but the role of weather variables such as air temperature and solar radiation, key determinants of ectotherm activity, are generally neglected. We aim to show how the effects of weather can be incorporated into individual-based models of butterfly movement thus allowing analysis of their effects.MethodsWe constructed a mechanistic movement model and calibrated it with high precision movement data on a widely studied species of butterfly, the meadow brown (Maniola jurtina), collected over a 21-week period at four sites in southern England. Day time temperatures during the study ranged from 14.5 to 31.5 °C and solar radiation from heavy cloud to bright sunshine. The effects of weather are integrated into the individual-based model through weather-dependent scaling of parametric distributions representing key behaviours: the durations of flight and periods of inactivity.ResultsFlight speed was unaffected by weather, time between successive flights increased as solar radiation decreased, and flight duration showed a unimodal response to air temperature that peaked between approximately 23 °C and 26 °C. After validation, the model demonstrated that weather alone can produce a more than two-fold difference in predicted weekly displacement.ConclusionsIndividual Based models provide a useful framework for integrating the effect of weather into movement models. By including weather effects we are able to explain a two-fold difference in movement rate of M. jurtina consistent with inter-annual variation in dispersal measured in population studies. Climate change for the studied populations is expected to decrease activity and dispersal rates since these butterflies already operate close to their thermal optimum.

Using maternal mule deer movements to estimate timing of parturition and assist fawn captures

ABSTRACTMovement patterns of maternal ungulates have been used to determine parturition dates and aid in locating fawns, which may be important for understanding reproductive rates (e.g., pregnancy and fetal), but such methods have not been validated for mule deer (Odocoileus hemionus). We first determined timing of parturition using vaginal implant transmitters (VITs) and then predicted timing of parturition using VITs in conjunction with Global Positioning System collar data in the Piceance Basin of northwestern Colorado, USA, during 2012–2014. We examined daily movement rate to determine differences in movement rate among days (7 days pre‐ and postpartum) and for movement patterns indicative of parturition. Mean daily movement rate (m/day) of 102 maternal deer decreased by 46% from 1 day preparturition ( = 1,253, SD = 1,091) to parturition date ( = 682, SD = 574), and remained at this low rate 1–7 days postpartum. We applied an independent data set to validate predicted parturition dates based on daily movement rate. We estimated day of parturition correctly (i.e., day 0), within 1–3 days postparturition, and ≥4 days postparturition of field‐reported dates for 10 (29%), 21 (60%), and 4 (11%) maternal females, respectively. For novel data sets, we predict that a mule deer female whose daily movement rate decreases by ≥46% and remains low ≥3 days postparturition particularly when preceded by a sudden increase in movement—has given birth. However, we caution that disturbance of deer by field crews should be minimized, and if birth sites are not found, neonatal mortality will be underestimated. Our results can help determine timing and general location of parturition as an aid in capturing fawns when the use of VITs is not feasible, with the ultimate objective of estimating pregnancy, fetal, and fawn survival rates if birth sites are found. © 2018 The Wildlife Society.

Movement responses of roe deer to hunting risk

ABSTRACTLarge herbivores respond to fluctuations in predation and hunting risk. The temporal scale of risk heterogeneity affects behavioral responses and determines the usefulness of metrics to quantify them. We present a conceptual framework to link anti‐predator responses to risk fluctuations and appropriate metrics, based on temporal scale. We applied this framework to investigate movement responses of roe deer (Capreolus capreolus) to hunting risk, measured using movement rate and home range size. Because movements are also affected by reproductive phases, we considered potential effects of the rut in parallel to hunting risk. We compared movements of male and female roe deer in a protected site versus 2 hunted sites during and outside the hunting season and rut. We detected differences in movement rates in response to different hunting management practices. We did not detect effects for hunting regimes or between sexes during the rut when using home range size as the response variable. During the hunting season, movement rates were lower in the hunted sites than in the protected site, irrespective of sex. We did not observe differences in movement rates among sites outside of the hunting season. Males had higher movement rates than females during the rut in only 1 site. Our findings supported the hypothesis that roe deer decrease movements when exposed to high hunting risk. The effect of the rut on movements was negligible except for 1 study site. We suggest that movement rate is a more useful metric than home range size for assessing movement responses to hunting. © 2018 The Wildlife Society

Sharing the same slope: Behavioral responses of a threatened mesocarnivore to motorized and nonmotorized winter recreation.

Winter recreation is a widely popular activity and is expected to increase due to changes in recreation technology and human population growth. Wildlife are frequently negatively impacted by winter recreation, however, through displacement from habitat, alteration of activity patterns, or changes in movement behavior. We studied impacts of dispersed and developed winter recreation on Canada lynx (Lynx canadensis) at their southwestern range periphery in Colorado, USA. We used GPS collars to track movements of 18 adult lynx over 4 years, coupled with GPS devices that logged 2,839 unique recreation tracks to provide a detailed spatial estimate of recreation intensity. We assessed changes in lynx spatial and temporal patterns in response to motorized and nonmotorized recreation, as well as differences in movement rate and path tortuosity. We found that lynx decreased their movement rate in areas with high‐intensity back‐country skiing and snowmobiling, and adjusted their temporal patterns so that they were more active at night in areas with high‐intensity recreation. We did not find consistent evidence of spatial avoidance of recreation: lynx exhibited some avoidance of areas with motorized recreation, but selected areas in close proximity to nonmotorized recreation trails. Lynx appeared to avoid high‐intensity developed ski resorts, however, especially when recreation was most intense. We conclude that lynx in our study areas did not exhibit strong negative responses to dispersed recreation, but instead altered their behavior and temporal patterns in a nuanced response to recreation, perhaps to decrease direct interactions with recreationists. However, based on observed avoidance of developed recreation, there may be a threshold of human disturbance above which lynx cannot coexist with winter recreation.

Effects of Nesting Bald Eagles (<i>Haliaeetus leucocephalus</i>) on Behaviour and Reproductive Rates in a Great Blue Heron (<i>Ardea herodias</i>) Colony in Ontario

Bald Eagles (Haliaeetus leucocephalus) and Great Blue Herons (Ardea herodias) are known to occasionally nest in mixed colonies, even though the former is one of the primary predators of the latter. I observed the two species in four heron colonies near Lake Simcoe, Ontario during two field seasons to assess whether rates of heron chick mortality or nest abandonment were greater in a colony that supported a nesting pair of Bald Eagles than in three nearby single-species colonies. I assessed the effects of eagle presence on heron behaviour using heron movement rates, the number of heron sentries left in colonies during the nesting period, heron nest mortality rates, and the average number of successfully fledged herons per nest. There was no statistically significant difference in movement rate among the four colonies, proportion of birds remaining as sentries, nor nest mortality rates. However, nests in the mixed colony successfully fledged significantly more heron young per nest than did nests in the single-species colonies. The mixed colony was located in a wetland and open lake system that provided extensive foraging habitat and an abundance of the preferred fish prey species of both Great Blue Herons and Bald Eagles, thus reducing predation pressure on the herons.

Physiological preparedness and performance of Atlantic salmon Salmo salar smolts in relation to behavioural salinity preferences and thresholds.

This study investigated the relationships between behavioural responses of Atlantic salmon Salmo salar smolts to saltwater (SW) exposure and physiological characteristics of smolts in laboratory experiments. It concurrently described the behaviour of acoustically tagged smolts with respect to SW and tidal cycles during estuary migration. Salmo salar smolts increased their use of SW relative to fresh water (FW) from April to June in laboratory experiments. Mean preference for SW never exceeded 50% of time in any group. Preference for SW increased throughout the course of smolt development. Maximum continuous time spent in SW was positively related to gill Na(+), K(+)-ATPase (NKA) activity and osmoregulatory performance in full-strength SW (measured as change in gill NKA activity and plasma osmolality). Smolts decreased depth upon reaching areas of the Penobscot Estuary where SW was present, and all fish became more surface oriented during passage from head of tide to the ocean. Acoustically tagged, migrating smolts with low gill NKA activity moved faster in FW reaches of the estuary than those with higher gill NKA activity. There was no difference in movement rate through SW reaches of the estuary based on gill NKA activity. Migrating fish moved with tidal flow during the passage of the lower estuary based on the observed patterns in both vertical and horizontal movements. The results indicate that smolts select low-salinity water during estuary migration and use tidal currents to minimize energetic investment in seaward migration. Seasonal changes in osmoregulatory ability highlight the importance of the timing of stocking and estuary arrival.

Between-watershed movements of two anadromous salmonids in the Arctic

A long-term study in the River Halselva in the Arctic region of Norway demonstrated that movements between watersheds were considerably higher in anadromous brown trout (Salmo trutta) than anadromous Arctic char (Salvelinus alpinus). Fourteen smolt year classes of both species were captured in a fish trap, individually tagged, and thereafter registered each time they passed the trap during their migration between the sea and fresh water every summer. Annual mean survival (i.e., recovery rate) after the first entry to sea as smolts was estimated as 31.4% in Arctic char and 26.6% in brown trout. Most surviving Arctic char returned to the River Halselva to overwinter after the same summer that they migrated to sea as smolts. However, several brown trout overwintered one to four times in other watersheds, mainly the considerably larger River Altaelva, before most eventually returned to the River Halselva upon maturation. The substantial difference in movement rate between watersheds between Arctic char (2.2%) and brown trout (39.6%) is expected to be a consequence of local geographic conditions combined with different habitat preferences of the two species.

Towed-float satellite telemetry tracks large-scale movement and habitat connectivity of myliobatid stingrays

Batoids are important mesopredators whose high mobility and extensive migrations can link seemingly distant food webs in coastal ecosystems. Despite this recognition, our knowledge of the movement patterns of many species is limited due to the logistical challenge of tracking these animals on multiple scales. Smart Positioning or Temperature (SPOT) satellite-linked transmitters allow for precise, multi-scale tracking of species that regularly use surface waters. To date, SPOTs have been predominantly used on sharks, with only a single application to a batoid. Given the epipelagic nature of myliobatid stingrays, we examined the potential for towed-float SPOT transmitters to monitor large-scale movements of two representative species: the Cownose Ray (Rhinoptera bonasus; n = 15) and Spotted Eagle Ray (Aetobatus narinari; n = 9). Tracking data identified several consistent outmigration patterns of Cownose Rays along the Mississippi-Alabama shelf and seasonal variation in movement rates along barrier island habitats. We also documented sex-related differences in movement rates and habitat use of Spotted Eagle Rays along the Bermuda platform, where males exhibited significantly higher movement rates than females and more transient behavior between inshore lagoons and outer coral reefs. Both Cownose and Spotted Eagle Rays were shown to exhibit connectivity among several habitat types along continental shelves in their respective locales, demonstrating future challenges to the management of these species over large spatial scales. While reductions in tag size and improved tethering techniques would undoubtedly broaden the applicability of towed-float satellite telemetry to other species and sizes, our work highlights the strong potential for this technology to provide insights into the spatial ecology and habitat use of myliobatid rays.

Spawning related movement of shovelnose sturgeon in the Missouri River above Fort Peck Reservoir, Montana

Summary The hypotheses of this study were (i) that shovelnose sturgeon would make upstream movements to spawn, (ii) movement of spawning fish would be greater in a year with higher discharge, and (iii) that spawning fish would have greater movements than reproductively inactive fish. Shovelnose sturgeon Scaphirhynchus platorynchus (Rafinesque, 1820) in five reproductive categories (e.g. males, confirmed spawning females, potentially spawning females, atretic females, and reproductively inactive females) were tracked in 2008 and 2009. All reproductive categories, except reproductively inactive females, exhibited large-scale movements and had omnidirectional movements. No differences in movement rates were observed in confirmed spawning females between years despite a 45% higher peak discharge in 2008 (839 m3 s−1) than in 2009 (578 m3 s−1). A peak discharge was obtained at a faster rate in 2008 (165 m3 s−1 day−1) than in 2009 (39 m3 s−1 day−1), and high discharge was of greater duration in 2008. Reproductively inactive females did not exhibit large-scale movements and their movement rate differed from other reproductive categories. Shovelnose sturgeon spawned in both years, despite highly varying hydrographs between years.

Functional responses, seasonal variation and thresholds in behavioural responses of moose to road density

SummaryUnderstanding the consequences of environmental change on populations is an essential prerequisite for informed management of ecosystems and landscapes. In lieu of quantifying fitness effects directly, which is often difficult, behavioural functional responses provide insight into how animals balance trade‐offs, and into thresholds in responses to environmental change.Here, we explore this principle using the response of mooseAlces alcesL. to roads and restricted‐access tracks as a case study. Because roads are associated with the conversion of conifer to mixed deciduous–conifer forest that provides better foraging opportunities, moose in Ontario favour areas of moderate road density at a landscape scale. At a finer scale, however, moose avoid roads. These opposing effects indicate a cost–benefit trade‐off. We quantified behavioural responses of moose to roads using road‐crossing rate. An expected distribution of crossing rates was derived from correlated random walk null model simulations.Moose exhibited a seasonally variable, nonlinear functional response in road‐crossing rate at the within seasonal range scale. A pronounced response to roads was observed when road density reached approximate thresholds of 0·2 and 0·4 km kmin summer and winter respectively. Road‐crossing rate was proportional to road density, though crossing rates were higher in summer than winter. Crossing rates were best explained by the interaction between mean movement rate and road density. Seasonal differences in road‐crossing rate arise from seasonal differences in movement rate and seasonal range area, but not road density within seasonal ranges. Within the protected park, moose did not appear to respond to tracks. Our analysis implies that for the majority of the landscape outside of protected areas the response of moose to roads is pronounced.Synthesis and applications. Identifying thresholds in nonlinear responses to landscape modification is a key management objective as they represent transition zones where small changes can have disproportionately large effects on wildlife populations. We establish these thresholds for moose and roads, but find no response to tracks, implying that the effects of tracks can be mitigated by restricting access to them. We discuss the implications of this work on the problem of moose–vehicle collisions.

A Common Marking Technique Affects Tadpole Behavior and Risk of Predation

AbstractIn many studies, it is necessary for researchers to mark individual animals for later identification. It is often assumed in the interpretation of these studies that marks have no effects on the biology of the animals. This assumption is insufficiently tested, and, when it is, coarse assessments of negative effects are often used, such as survival and growth under simplified laboratory conditions. We examined the consequences of a common larval amphibian marking technique (staining with methylene blue) for wood frog tadpole behavior and survival in an ecologically realistic scenario (predation). We measured a number of tadpole behavioral variables, under baseline conditions and in the presence of olfactory cues of a predator, for marked and unmarked tadpoles. We then exposed pairs of tadpoles (one marked and one unmarked) to one of two predators and tested for the effects of marking on the susceptibility of tadpoles to predation. We found that marking suppressed the increase in movement rate that typically occurred in (unmarked) tadpoles in the presence of predator cues. Marked tadpoles were significantly more likely to be captured by predators, an effect that could not be attributed to this difference in movement rate. These results raise concern about the use of this staining method and highlight the need for studies involving marked animals to thoroughly address any relevant effects the marks may have on the biology of the subjects.

Human selection of elk behavioural traits in a landscape of fear

Among agents of selection that shape phenotypic traits in animals, humans can cause more rapid changes than many natural factors. Studies have focused on human selection of morphological traits, but little is known about human selection of behavioural traits. By monitoring elk (Cervus elaphus) with satellite telemetry, we tested whether individuals harvested by hunters adopted less favourable behaviours than elk that survived the hunting season. Among 45 2-year-old males, harvested elk showed bolder behaviour, including higher movement rate and increased use of open areas, compared with surviving elk that showed less conspicuous behaviour. Personality clearly drove this pattern, given that inter-individual differences in movement rate were present before the onset of the hunting season. Elk that were harvested further increased their movement rate when the probability of encountering hunters was high (close to roads, flatter terrain, during the weekend), while elk that survived decreased movements and showed avoidance of open areas. Among 77 females (2-19 y.o.), personality traits were less evident and likely confounded by learning because females decreased their movement rate with increasing age. As with males, hunters typically harvested females with bold behavioural traits. Among less-experienced elk (2-9 y.o.), females that moved faster were harvested, while elk that moved slower and avoided open areas survived. Interestingly, movement rate decreased as age increased in those females that survived, but not in those that were eventually harvested. The latter clearly showed lower plasticity and adaptability to the local environment. All females older than 9 y.o. moved more slowly, avoided open areas and survived. Selection on behavioural traits is an important but often-ignored consequence of human exploitation of wild animals. Human hunting could evoke exploitation-induced evolutionary change, which, in turn, might oppose adaptive responses to natural and sexual selection.

Variability in movement dynamics of topminnow (Fundulus notatusandF. olivaceus) populations

Abstract – Movement and dispersal patterns are key biological processes across a range of organisational levels. TheFundulus notatusspecies complex includes several species with similar ecological niches that exhibit broadly overlapping ranges. We conducted a mark–recapture study on two of the most widely distributed members of this species complex to improve our understanding of their movement and habitat use. A population ofF. notatuswas studied between June and August of 2008 and 2009 in Cahokia Creek, a small tributary of the Mississippi River in Illinois, along with a parallel study ofFundulus olivaceusbetween May and July of 2009 in Big Creek, a tributary of the Pascagoula River in Mississippi. Fish were recaptured approximately weekly, and habitat variables were measured. Estimated daily movement rates varied significantly both between locations and between years.Fundulus olivaceusin Big Creek moved <1 m per day, whileF. notatusin Cahokia Creek in 2009 moved nearly 23 m per day. The distribution of movements was strongly leptokurtic in all three data sets. Differences in movement rates were attributed to significant differences in population size and habitat characteristics. Our data did not support the hypothesis that populations consist of distinct mobile and resident components. Instead, individual fish went through periods of little or no movement followed by extensive movement (consistent with the home range shift model of fish movement). We discuss the implications these results have for contact zone dynamics between these two species.

A Spatial Dimension of Ecology: Ilkka Hanski Crafoord Laureate in 2011

The Finnish ecologist Ilkka Hanski is awarded the Crafoord Prize in Biosciences for 2011 for his pioneering studies of how spatial variation affects the dynamics of animal and plant populations. Earlier Crafoord laureates in Biosciences include Robert L. Trivers (2007), Carl R. Woese (2003), John Maynard Smith, Ernst Mayr and George C. Williams (1999), Robert May (1996), Seymour Benzer and William T. Hamilton (1993), Paul R. Ehrlich and Edward O. Wilson (1990), Eugene P. Odum and Howard T. Odum (1987) and Daniel H. Janzen (1984). A common textbook defines ecology as the study of the mechanisms behind species abundance and distribution where each species can be characterized by the size and location of its populations. Ecological populations are rarely constant over time and space but vary due to factors both intrinsic to the system and extrinsic environmental variation. Even in a spatially homogeneous environment, populations of predator and prey may show patchy distributions due to, for example, differences in movement rates. In most cases, variation in population sizes over space (and time) is, however, a result of spatial variation in the distribution of suitable habitats, and it is in this context that Ilkka Hanski has made his major contributions. Inspired by a short paper by Richard Levins published in the late 1960s, Hanski initiated a development of both theory and empirical research that has now grown to become a major research area in ecology. Baptized as Metapopulation Ecology (Hanski 1999), this research now engages ecologists all over the world in studies in many different kinds of environments. Although animals and plants are most common, the metapopulation theories are used for all major groups of organisms. As in most scientific breakthroughs, the basic idea is quite simple. Each population is seen as an “individual”, which is born (the population is founded by colonization of a site) and ultimately dies (the population goes extinct). The likelihood of colonization is dependent on the presence of other populations in the surroundings (the isolation of the site) and the risk of extinction is dependent in the population size (the area of the site). From this simple basis of habitat area and isolation, Hanski has developed more complex theory to deal with the realism that makes ecological studies such a challenge. These extensions consider aspects such as population dynamics in local populations and stochastic variation. Along with the theoretical development, Hanski has also performed outstanding field studies, the most important being done on a butterfly (Melitaea cinxia) and its host plants in the Aland archipelago. For conservation biologists, Hanski’s studies have provided a tool box for analyzing how species are affected by habitat change and fragmentation. As habitat loss is considered as the major factor behind biodiversity decline and species extinction, the metapopulation theory has become a cornerstone of conservation biology. One major insight for conservation biology is the concept of “extinction debt” relating to the time delay between habitat loss and the extinction of a species which is particularly long when it is close to its extinction threshold. Metapopulation theory has also led to further developments of ecological theory concerned with spatial aspects of whole communities and ecosystems—metacommunityecology and meta-ecosystemecology—no doubt providing us with important new insights on the spatial dimension of the dynamics of ecological systems. In particular, metacommunity theory has developed into a rich theory studying the effects of trade-offs related to colonization and competitive ability, species-specific responses to environmental heterogeneity, stochastic demographic processes and dispersal limitation on species diversity in heterogeneous landscapes.

Is it possible to individually identify mammals with no natural markings using camera-traps? A controlled case-study with lowland tapirs

Estimating population size or density and its trendsthroughout time is one of the main goals in conservationresearch. This basic information is critical to defineconservation priorities (Mackenzie 2005), or to evaluateeffectiveness of management policies. Several methodshave been used to estimate the absolute abundance ofmammals, such as capture-mark-recapture (Nichols andPollock 1983); line transect (Peres and Palacios 2007);aerial counts (Moura˜o et al. 2000); defecation rates(Plumptre and Harris 1995) and footprints measure-ments (Lizcano and Cavelier 2000).Camera traps are acknowledged as important toolsfor monitoring cryptic species and further developmentof their use has led to population estimation of naturalmarked animals by means of well consolidated cap-tured-recapture models (Karanth 1995; Karanth andNichols 1998). Singular species that can be individuallyidentified through photographs, though, account foronly a small fraction of the total species assemblageregistered in the majority of the camera trapping studies(Carbone et al. 2001).In this context, two different approaches have beenproposed to apply abundance estimations with cameratrapping data for a wider range of species. First,in a simple and direct way, trapping rates (photographrecords/trapping effort) became a widely used piece ofinformation presented in most studies (Carbone et al.2001; Trolle and Ke´ry 2005). Its usage as a relative indexof abundance has been supported by evidence of theexistence of significant correlation between trappingrates and independent density estimations in a numberof species (Carbone et al. 2001; O’brien et al. 2003). Thisprocedure has been criticized (Jennelle et al. 2002) sinceit does not consider the effects of the probability ofdetection in the trapping rate and ignores that differ-ences in movement rates also influences the trapping.Second, the broadening of what would be consideredindividually identifiable species to include cases of non-spotted or non-striped ones has been an alternative toestimate densities in a wider range of species, such asmanned wolf (Crysocyon brachyurus)(Trolle et al. 2006),cougars (Puma concolor)(Kelly et al. 2008) and tapirs(Tapirus spp.)(Holden et al. 2003; Noss et al. 2003;Trolle et al. 2008). Yet, conventional methods foranalysis of capture-recapture data do not account forerrors in identification of individuals and whether theassumption of recognition of individuals has beenfulfilled or not was never properly tested in most ofthese studies.Therefore, we aimed to test the ability of researchersto identify individuals of lowland tapir (Tapirusterrestris) in a set of photographs of a population withknown size. Camera trapping was conducted in thesemi-captive area (200ha) located in the coastal plain ofthe Serra do Tabuleiro State Park (STSP), southern

Differential responses of three Agriotes click beetle species to pheromone traps

Abstract1 Previous work had suggested that adult male click beetles (Agriotes spp.) show differential responses to species specific pheromone traps. This hypothesis was tested using mark–release–recapture methods to estimate the maximum sampling range and the effective sampling area of traps for three species.2 Captured beetles of the species Agriotes lineatus, Agriotes obscurus and Agriotes sputator were marked to show the direction of release, the distance of the release point from the trap and the replicate. Analysis of variance showed that there were significant differences in recapture rates between species and release distances. There were no significant differences between release direction and replicates.3 Calculated linear speeds suggested differences in movement rates in the order: A. lineatus > A. obscurus > A. sputator. There were also substantial differences between the species in the maximum sampling ranges and effective sampling areas of the traps. These placed the species in the same order.4 The results are used to estimate the minimum cost of mass trapping programmes to prevent males from mating, giving values of €165/ha/year (A. lineatus), €247.5/ha/year (A. obscurus) and €2343/ha/year (A. sputator).5 Implications for the use of pheromone traps in wireworm pest management are discussed. It is concluded that current U.K. recommendations based on the cumulative total catch of the three species over a sampling season can be improved by considering the spatial relationships between the adult trapping system and larval distribution. The current constraint to this is the general inability to separate wireworms into species.

Poststocking Movements and Habitat Use of Hatchery‐Reared Juvenile Pallid Sturgeon in the Missouri River below Fort Randall Dam, South Dakota and Nebraska

AbstractTelemetry was used to evaluate seasonal and diel movement patterns, general habitat use, survival, and spatial distributions of hatchery‐reared juvenile pallid sturgeon Scaphirhynchus albus stocked in the Missouri River below Fort Randall Dam, South Dakota and Nebraska. Sampling occurred at about 2‐week intervals during spring through fall. Of 22 ultrasonically tagged fish, 13 were intensively followed to assess hourly diel movement rates. A total of 258 relocations were made for the 22 tagged fish; 19 fish were relocated at least once, and 16 were relocated multiple times. At least 68% of tagged fish survived for 2.5 years. In 2000, fish were found mainly upstream of the stocking site, whereas in 2001 and 2002 the entire reach was used. Juveniles were found primarily in the main channel at depths exceeding 80% of the maximum channel cross‐section depth, where bottom current velocities ranged from 0.1 to 0.9 m/s. Clusters of juvenile pallid sturgeon (i.e., two or more fish) within 750 m of each other were observed on 15 dates, and clusters of juveniles within 500 m of each other were observed on 10 dates. Clusters were observed during all seasons. Mean (±2 SE) range of movement was significantly less in 2000 (8.3 ± 5.8 km) than in 2001 (29.3 ± 8.8 km) and 2002 (28.9 ± 15.0 km). We detected no significant differences in movement rates among years, seasons, or diel periods (i.e., dawn, daytime, dusk, and night). Our study indicates that range of movements of juvenile pallid sturgeon based on shorter studies (i.e., ≤1 year) should be interpreted cautiously because hatchery‐reared fish may not have acclimated to the riverine environment until the second year after stocking. Based on survival and distribution of juvenile pallid sturgeon throughout the study area, we conclude that this reach is suitable for recovery efforts.

Radiotelemetry reveals differences in individual movement patterns between outbreak and non‐outbreak Mormon cricket populations

Abstract. 1. Outbreaks of insect pest populations are common and can have devastating effects on natural communities and on agriculture. Little is known about the causes of these outbreaks or the causes ofen massemigrations during outbreaks.2. Flightless Mormon crickets (Anabrus simplex) were the focus of this study. They are a katydid species that forms large, dense, mobile groups (migratory bands) during outbreak periods, eating vegetation in their path.3. Radiotelemetric methods were used to measure differences in movement rate and directionality in outbreak and non‐outbreak populations, testing the hypothesis that these populations differ in their travel rate and consistency of direction.4. Daily individual movement in outbreak populations differs substantially from non‐outbreak populations that are at much lower density. In addition to large differences in distances travelled (1.6 km as compared with 1 m) and rates of travel, there is evidence for collective movement among individual Mormon crickets travelling in migratory bands.5. These data suggest that the direction of group movement may be influenced by local environmental conditions such as wind direction and movement of nearby band members. This work forms the basis for ongoing work testing hypotheses about mass migrations in outbreak populations.