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At least 271 records · Page 15Linked to original sources
USGS2011

Temporal variation in bird and resource abundance across an elevational gradient in Hawaii

We documented patterns of nectar availability and nectarivorous bird abundance over ~3 years at nine study sites across an 1,800-m elevational gradient on Hawaii Island to investigate the relationship between resource variation and bird abundance. Flower density (flowers ha -1 ) and nectar energy content were measured across the gradient for the monodominant 'Ōhi'a ( Metrosideros polymorpha ). Four nectarivorous bird species were captured monthly in mist nets and surveyed quarterly with point-transect distance sampling at each site to examine patterns of density and relative abundance. Flowering peaks were associated with season but not rainfall or elevation. Bird densities peaked in the winter and spring of each year at high elevations, but patterns were less clear at middle and low elevations. Variability in bird abundance was generally best modeled as a function of elevation, season, and flower density, but the strength of the latter effect varied with species. The low elevations had the greatest density of flowers but contained far fewer individuals of the two most strongly nectarivorous species. There is little evidence of large-scale altitudinal movement of birds in response to 'Ōhi'a flowering peaks. The loose relationship between nectar and bird abundance may be explained by a number of potential mechanisms, including (1) demographic constraints to movement; (2) nonlimiting nectar resources; and (3) the presence of an "ecological trap," whereby birds are attracted by the high resource abundance of, but suffer increased mortality at, middle and low elevations as a result of disease.

Hawai'i↗
USGS2015

Home range, habitat use, and movement patterns of non-native Burmese pythons in Everglades National Park, Florida, USA

Background Studies on the spatial ecology of invasive species provide critical information for conservation managers such as habitat preferences and identification of native species at risk of predation. To understand the spatial ecology of non-native Burmese pythons ( Python molurus bivittatus ), now well-established in Everglades National Park and much of South Florida USA, we radio-tracked 19 wild-caught adult pythons, 16 with VHF tags during 2006 through 2009 and 3 by GPS tags between 2010 and 2011. Our goal was to identify individual core-use areas and quantify home ranges, as well as to explore correlations of python movements with environmental parameters such as the presence of surface water. Results Radio-tracking periods ranged from 87 to 697 days for snakes with VHF tags, with a total of 5,119 tracking days (mean ± 1 SD = 319.9 ± 184.3 days); GPS tracking periods ranged from 12 to 93 days, with a total of 146 tracking days (mean ± 1 SD = 48.7 ± 40.7 days). We observed mean individual radio-tracked python home ranges of 22.5 km 2 (2250 ha) with overall low site fidelity; all home ranges were within the park boundary. Python core-use areas included slough and coastal habitat types, and we delineated 18 common-use areas (that is, areas where individual core-use areas spatially overlapped). Tree islands were a principal feature of common-use areas, even if they were not the predominant habitat type. Multiple common-use areas were in proximity to roads. The longest movements of individual pythons correlated well with presence of surface water, and occurred during both wet and dry seasons. Conclusions High-use areas determined from python habitat-use and movement data may be optimal locations for targeted control efforts and further studies on impacts to native fauna.

Florida↗
USGS2019

Predicting functional responses in agro-ecosystems from animal movement data to improve management of invasive pests

Functional responses describe how changing resource availability affects consumer resource use, thus providing a mechanistic approach to prediction of the invasibility and potential damage of invasive alien species (IAS). However, functional responses can be context dependent, varying with resource characteristics and availability, consumer attributes, and environmental variables. Identifying context dependencies can allow invasion and damage risk to be predicted across different ecoregions. Understanding how ecological factors shape the functional response in agro‐ecosystems can improve predictions of hotspots of highest impact and inform strategies to mitigate damage across locations with varying crop types and availability. We linked heterogeneous movement data across different agro‐ecosystems to predict ecologically driven variability in the functional responses. We applied our approach to wild pigs ( Sus scrofa ), one of the most successful and detrimental IAS worldwide where agricultural resource depredation is an important driver of spread and establishment. We used continental‐scale movement data within agro‐ecosystems to quantify the functional response of agricultural resources relative to availability of crops and natural forage. We hypothesized that wild pigs would selectively use crops more often when natural forage resources were low. We also examined how individual attributes such as sex, crop type, and resource stimulus such as distance to crops altered the magnitude of the functional response. There was a strong agricultural functional response where crop use was an accelerating function of crop availability at low density (Type III) and was highly context dependent. As hypothesized, there was a reduced response of crop use with increasing crop availability when non‐agricultural resources were more available, emphasizing that crop damage levels are likely to be highly heterogeneous depending on surrounding natural resources and temporal availability of crops. We found significant effects of crop type and sex, with males spending 20% more time and visiting crops 58% more often than females, and both sexes showing different functional responses depending on crop type. Our application demonstrates how commonly collected animal movement data can be used to understand context dependencies in resource use to improve our understanding of pest foraging behavior, with implications for prioritizing spatiotemporal hotspots of potential economic loss in agro‐ecosystems.

California. Florida, Georgia, Louisiana, Missouri,↗
USGS2021

Movement, recruitment, and abundance relationships of Prairie Chub: An endemic Great Plains cyprinid

The Prairie Chub Macrhybopsis australis is a poorly studied endemic cyprinid of the upper Red River basin and is listed as threatened in Texas and of greatest conservation need in Oklahoma. Hypothesized mechanisms have been proposed to explain the decline of pelagic broadcast spawning minnows including disrupted spawning cues, reduced recruitment, degraded habitat complexity, and reduced water availability and connectivity. Our study objectives were to evaluate Prairie Chub movement, identify spawn timing, and estimate abundance of Prairie Chub at locations in the upper Red River basin. We assessed Prairie Chub movement using a mark-recapture experiment with multiple tag and recapture occasions during late spring through summer (i.e., May-August) of 2019 and 2020. We tagged 5,771 Prairie Chub during summers of 2019 and 2020 and recaptured 213 fish across both summers. We conducted recapture events at approximately 2-week intervals from late May to August of 2019 and 2020. Movement by Prairie Chub was consistently greater than expected under the restricted movement paradigm. The average expected movement distance of the stationary population component was 2 m in 2019 and 3 m in 2020, whereas the expected average movement distance for the mobile population component was 42 m in 2019 and 75 m in 2020. We found no evidence of upstream bias in adult Prairie Chub movement during our study. We processed otoliths for 2,017 age-0 Prairie Chub across 7 rivers and two spawning seasons (i.e., 2019 and 2020). The likelihood of spawning and frequency of observed hatches per spawning date were higher in 2019 compared to 2020. The probability of spawning increased with increasing scaled discharge and average temperature in both 2019 and 2020. Spawning was more likely to occur earlier in the sample season though substantial spatial and temporal variation in spawning success was evident among rivers. The number of successful hatches observed per spawning day was highest in the Pease and Red rivers and lowest in the Salt Fork and South Wichita rivers for both years. We conducted 104 abundance surveys in 2019 and 2020. Our abundance estimates were consistently lower in upstream reaches, higher in downstream reaches, and more variable in mid reaches. We found Prairie Chub abundance was related to several covariates, but abundance did not vary much between years. Overall, adult Prairie Chub abundance was higher in the eastern portion of their range and increased with increasing discharge and turbidity but decreased at higher water temperatures. Adult Prairie Chub abundance had a quadratic relationship with salinity where Prairie Chub density peaked at a salinity of 10 ppt and then declined by nearly 100% when salinities reached 20 ppt. Our juvenile Prairie Chub abundance model had similar but weaker relationships with covariates compared to the adults; however, juvenile abundance was higher in 2020 compared to 2019. Our results indicate conservation of Prairie Chub and ecologically similar species would benefit from maintaining broadly connected habitats (i.e., for movement and drift). We show substantial variation in spawning patterns among rivers that has important implications for developing conservation actions. If agencies are concerned about abundance of Prairie Chub, then management agencies may want to consider the strong relationship with salinity when desalinization projects are proposed. Considering how salinity may narrow the realized niche of Prairie Chub, agencies interested in Prairie Chub persistence may want to prevent large changes in salinity concentrations in the species’ remaining habitat.

Report↗
USGS2026

A 2.5 km movement by a potentially ill white-tailed deer along Nantasket Beach in suburban Massachusetts, USA

White-tailed deer ( Odocoileus virginianus ) ecology has received significant research attention, yet there is a need for further synthetic work on the species across environmental contexts and research areas. Opportunistic natural history accounts can help identify new conceptual links and research directions by offering new observations and ideas, synthesizing context from the literature, and highlighting gaps in understanding. We provide an opportunistic account of a 2.5 km movement of a white-tailed deer walking, wading, and swimming along Nantasket Beach in a suburban context in Massachusetts, USA. The deer displayed behaviors that could potentially be reflective of trauma, disorientation, or illness, including possibly symptomatic head movements and crouching behavior. The behavior of the deer may also have been influenced by the coastal and suburban context in which the observation took place. Our account explores swimming, deer behavior, and possible illness in a coastal, suburban context. We highlight the need for additional research on the ecology and management of white-tailed deer, including swimming and disease in coastal, marine, and developed contexts, and intersections across these areas.

Massachusetts↗
USGS2015

Crocodylus acutus (American Crocodile). Long distance juvenile movement

Crocodylus acutus (American Crocodile) is the most widely distributed New World crocodilian species with its range extending from Peru in the south to the southern tip of peninsular Florida in the north. Crocodylus acutus occupies primarily coastal brackish water habitat, however it also occurs in freshwater to hypersaline habitats (Thorbjarnarson 2010. In Crocodiles. Status Survey and Conservation Action Plan. [Third Edition], American Crocodile Crocodylus acutus, pp. 46–53 S.C. Manolis and C. Stevenson. Crocodile Specialist Group, Darwin). There is limited literature on long distance movements of juvenile crocodilians worldwide and no literature on juvenile crocodiles in Florida. However, adult C. acutus in Florida have been documented to make seasonal movements of 5–15 km from preferred foraging habitat to nesting beaches (Mazzotti 1983. The Ecology of Crocodylus acutus in Florida. PhD Dissertation. The Pennsylvania State University, University Park, Pennsylvania. 161pp), and one adult was documented making a 35 km trip from her nest site to preferred foraging habitat (Cherkiss et. al. 2006. Herpetol. Rev. 38:72–73). Rodda (1984. Herpetologica 40:444–451) reported on juvenile C. acutus movement in Gatun Lake, Panama, and found that juveniles stayed within 1 km of their nest site for the first month. Movements of juvenile Crocodylus porosus (Saltwater Crocodile) in a river system in Northern Australia showed a maximum movement of 38.9 km from a known nest site, with the majority of the crocodiles staying within 15.6 km downstream to 6.8 km upstream (Webb and Messel 1978. Aust. Wildlife Res. 5:263–283). Juvenile movement of Crocodylus niloticus (Nile Crocodile) in Lake Ngezi, Zimbabwe showed crocodiles restricted their movements from 1.0 km up to 4.5 km through the wet and dry seasons (Hutton 1989. Am. Zool. 29:1033–1049). Long distance movements of alligators were recorded for sizes ranging from 28 cm to 361 cm in a coastal refuge in Louisiana, where the distance traveled ranged from 0.3 km to 90.2 km. The data showed that the smaller alligators moved greater distance than larger ones (Lance et al. 2011. Southeast Nat. 10:389–398). An ongoing 30 year mark and recapture study for Crocodylus acutus in Florida allowed us to look at long distance movement (>30 km) of juveniles (30km). Initial and most recent captures as a juvenile were used to analyze distances moved (Fig. 1). These distances were measured linearly between capture locations. Maximum linear distances of 76.3 km and 69.6 km were recorded for animals 4838 and 6662. All crocodiles moved from nesting habitat through potentially optimal nursery habitat prior to reaching their recapture locations. These juvenile long distance movements could be due to larger crocodiles facilitating their dispersal from the nest location (Lance et al. 2011. op. cit.). These data (Table 1.) support that there is exchange of individuals among the nesting colonies and our ongoing efforts to monitor this threatened species allow us to make observations of how juvenile crocodiles are moving throughout the landscape in an ecosystem currently undergoing restoration.

Herpetological Review↗
USGS2015

Plethodon cinerius (eastern red-backed salamander) movement

Lungless salamanders (family Plethodontidae) are relatively sedentary and are presumed to have limited dispersal ability (Marsh et al. 2004. Ecology 85:3396–3405). Site fidelity in Plethodontidae is high, and individuals displaced 90 m return to home territories (Kleeberger and Werner 1982. Copeia 1982:409–415). Individuals defend territories (Jaeger et al. 1982. Anim. Behav. 30:490–496) and female home ranges have been estimated to be 24.34 m2 (Kleeberger and Werner 1982, op. cit.). Females may seek out suitable subsurface habitat to oviposit eggs, yet little is known about their maximum movement distances (Petranka 1998. Salamanders of the United States and Canada. Smithsonian Institution Press, Washington. 587 pp.). On 18 September 2014, a female P. cinereus (lead back morphotype; SVL = 44.68 mm; 0.89 g) was found under a coverboard during a standard sampling event and uniquely marked using visual implant elastomer at the S.O. Conte Anadromous Fish Research Center, Massachusetts, USA (42.59280°N, 72.58070°W, datum WGS84; elev. 74 m). This individual was subsequently recaptured at ~1500 h on 8 October 2014 under a coverboard within 3 m of the original capture location and then again ~1430 h on 16 October 2014 under a log, within the same forest patch, though in a 50 x 150 m area adjacent to the original study area. Because we found the marked salamander while collecting multiple individuals for a laboratory study, the exact recapture location of the marked individual is not known. However, the distance between the 8 October capture location and the nearest edge of the 16 October search area (i.e. 50 x 150 m) was 143 m, indicating a minimum movement distance. As far as we are aware, this is the longest recorded movement for P. cinereus by more than 53 m (Kleeberger and Werner 1982, op. cit.). This finding followed a rain event of 1.63 cm within 24 h and the second largest sustained rain event during October. The movement we observed may have been due to disturbance from handling and marking, although this was minimized in the field.

Herpetological Review↗
USGS2015

Home in the heat: Dramatic seasonal variation in home range of desert golden eagles informs management for renewable energy development

Renewable energy is expanding quickly with sometimes dramatic impacts to species and ecosystems. To understand the degree to which sensitive species may be impacted by renewable energy projects, it is informative to know how much space individuals use and how that space may overlap with planned development. We used global positioning system–global system for mobile communications (GPS-GSM) telemetry to measure year-round movements of golden eagles ( Aquila chrysaetos ) from the Mojave Desert of California, USA. We estimated monthly space use with adaptive local convex hulls to identify the temporal and spatial scales at which eagles may encounter renewable energy projects in the Desert Renewable Energy Conservation Plan area. Mean size of home ranges was lowest and least variable from November through January and greatest in February–March and May–August. These monthly home range patterns coincided with seasonal variation in breeding ecology, habitat associations, and temperature. The expanded home ranges in hot summer months included movements to cooler, prey-dense, mountainous areas characterized by forest, grasslands, and scrublands. Breeding-season home ranges (October–May) included more lowland semi-desert and rock vegetation. Overlap of eagle home ranges and focus areas for renewable energy development was greatest when eagle home ranges were smallest, during the breeding season. Golden eagles in the Mojave Desert used more space and a wider range of habitat types than expected and renewable energy projects could affect a larger section of the regional population than was previously thought.

California↗
USGS2020

Hierarchical computing for hierarchical models in ecology

Bayesian hierarchical models allow ecologists to account for uncertainty and make inference at multiple scales. However, hierarchical models are often computationally intensive to fit, especially with large datasets, and researchers face trade-offs between capturing ecological complexity in statistical models and implementing these models. We present a recursive Bayesian computing (RB) method that can be used to fit Bayesian models efficiently in sequential MCMC stages to ease computation and streamline hierarchical inference. We also introduce transformation-assisted RB (TARB) to create unsupervised MCMC algorithms and improve interpretability of parameters. We demonstrate TARB by fitting a hierarchical animal movement model to obtain inference about individual- and population-level migratory characteristics. Our recursive procedure reduced computation time for fitting our hierarchical movement model by half compared to fitting the model with a single MCMC algorithm. We obtained the same inference fitting our model using TARB as we obtained fitting the model with a single algorithm. For complex ecological statistical models, like those for animal movement, multi-species systems, or large spatial and temporal scales, the computational demands of fitting models with conventional computing techniques can limit model specification, thus hindering scientific discovery. Transformation-assisted RB is one of the most accessible methods for reducing these limitations, enabling us to implement new statistical models and advance our understanding of complex ecological phenomena.

Article↗
USGS2013

Intra-population variation in activity ranges, diel patterns, movement rates, and habitat use of American alligators in a subtropical estuary

Movement and habitat use patterns are fundamental components of the behaviors of mobile animals and help determine the scale and types of interactions they have with their environments. These behaviors are especially important to quantify for top predators because they can have strong effects on lower trophic levels as well as the wider ecosystem. Many studies of top predator movement and habitat use focus on general population level trends, which may overlook important intra-population variation in behaviors that now appear to be common. In an effort to better understand the prevalence of intrapopulation variation in top predator movement behaviors and the potential effects of such variation on ecosystem dynamics, we examined the movement and habitat use patterns of a population of adult American alligators ( Alligator mississippiensis ) in a subtropical estuary for nearly four years. We found that alligators exhibited divergent behaviors with respect to activity ranges, movement rates, and habitat use, and that individualized behaviors were stable over multiple years. We also found that the variations across the three behavioral metrics were correlated such that consistent behavioral types emerged, specifically more exploratory individuals and more sedentary individuals. Our study demonstrates that top predator populations can be characterized by high degrees of intra-population variation in terms of movement and habitat use behaviors that could lead to individuals filling different ecological roles in the same ecosystem. By extension, one-size-fits-all ecosystem and species-specific conservation and management strategies that do not account for potential intra-population variation in top predator behaviors may not produce the desired outcomes in all cases.

Estuarine, Coastal and Shelf Science↗
USGS2016

Winter and summer home ranges of American White Pelicans (Pelecanus erythrorhynchos) captured at loafing sites in the southeastern United States

Satellite telemetry was used to investigate summer and winter home ranges for resident and migrant American White Pelicans ( Pelecanus erythrorhynchos ) captured in the southeastern United States between 2002 and 2007. Home range utilization distributions were calculated using 50% and 95% kernel density estimators with the plug-in bandwidth selector. Mean summer home ranges (95%) varied from 177 to 4,710 km 2 and mean winter home ranges (95%) ranged from 185 to 916 km 2 . Mean 50% and 95% home ranges of adult American White Pelicans during summer tended to be larger than those during winter, whereas mean 50% and 95% home ranges of immature pelicans during summer tended to be smaller than those during winter. Home ranges for all American White Pelicans encompassed the latitude range of 24°–55° N, including wintering, stop over, and nesting habitat. These data provide baseline movement and home range data for future studies of American White Pelican ecology.

Alabama, Arkansas, Louisiana, Mississippi↗
USGS2026

Seasonal migrations and other movements

In the past 25 years new information has been obtained on the migrations and movements of mountain sheep (bighorn [Ovis canadensis], thinhorn [Ovis dalli]). This chapter provides a comprehensive overview of mountain sheep migration and other movements across their broad distribution in western North America. Across the range of mountain sheep, migrations and other seasonal movements define a complex movement portfolio that relates to and supports all aspects of mountain sheep ecology. Bighorn and thinhorn species have examples of migratory behaviors that span the continuum between annual residents and long-distance migrants. Migratory behaviors can be characterized as low- or high-elevation residents; elevational migrations and other variants; and geographic migrants. Native populations that have been extant on the landscape without notable human intervention have greater migratory propensity and more diverse migratory portfolios due to the maintenance of migration through cultural learning and social transmission. Restored and augmented populations, where the population-level knowledge of migration has been lost or greatly reduced, are largely nonmigratory, although translocations show some ability to restore short-distance elevational migrations. Seasonal spring and fall migrations are less common in desert bighorn sheep (O. canadensis spp.) or bighorn sheep living in canyon or prairie breaks landscapes. Mineral lick visitation is important and common across the range of mountain sheep. Managing for migratory diversity can help to sustain migratory behavior in the face of climate change and other anthropogenic pressures, which can limit landscape connectivity between seasonal ranges or alter the spatiotemporal dynamics of regional phenology with cascading effects to other biotic and abiotic interactions such as the need to balance forage and predation risk or the spatial refugia with increased temperatures.

Book chapter↗
USGS1989

National Research Program of the Water Resources Division, U.S. Geological Survey: Fiscal Year 1988

The National Research Program (NRP) of the US Geological Survey 's Water Resources Division (WRD) had its beginnings in the late 1950 's when ' core research ' was added as a line item to the Congressional budget. Since that time, the NRP has grown to encompass a broad spectrum of scientific investigations. The sciences of hydrology, mathematics, chemistry, physics, ecology, biology, geology, and engineering are used to gain a fundamental understanding of the processes that affect the availability, movement, and quality of the Nation 's water resources. The NRP is located principally in Reston, VA, Denver, CO, and Menlo Park , CA. The NRP is subdivided into six disciplines as follows: (1) Ecology; (2) Geomorphology and Sediment Transport; (3) Groundwater Chemistry; (4) Groundwater Hydrology; (5) Surface Water Chemistry; and (6) Surface Water Hydrology. The report provides current information about the NRP on an annual basis. Organized by the six research disciplines, the volume contains a summary of the problem, objective, approach, and progress for each project that was active during fiscal year 1988.

Open-File Report↗
USGS2021

Informed breeding dispersal following stochastic changes to patch quality in a pond-breeding amphibian

The unidirectional movement of animals between breeding patches (i.e. breeding dispersal) has profound implications for the ecological and evolutionary dynamics of spatially structured populations. In spatiotemporally variable environments, individuals are expected to adjust their dispersal decisions according to information gathered on the environmental and/or social cues that reflect the fitness prospects in a given breeding patch (i.e. informed dispersal). A paucity of empirical work limited our understanding of the ability of animals to depart from low-quality breeding patches and settle in high-quality breeding patches. We examined the capacity of individuals to respond to stochastic changes in habitat quality via informed breeding dispersal in a pond-breeding amphibian. We conducted a 5-year (2015–2019) capture–recapture study of boreal toads Anaxyrus boreas boreas ( n = 1,100) that breed in beaver ponds in western Wyoming, USA. During early spring of 2017, an extreme flooding event destroyed several beaver dams and resulted in the loss of breeding habitat. We used multi-state models to investigate how temporal changes in pond characteristics influenced breeding dispersal, and determine whether movement decisions were in accordance with prospects for reproductive fitness. Boreal toads more often departed from low-quality breeding ponds (without successful metamorphosis) and settled in high-quality breeding ponds (with successful metamorphosis). Movement decisions were context-dependent and associated with pond characteristics altered by beaver dam destruction. Individuals were more likely to depart from shallow ponds with high vegetation cover and settle in deep ponds with low vegetation cover. The probability of metamorphosis was related to the same environmental cues, suggesting that boreal toads assess the fitness prospects of a breeding patch and adjust movement decisions accordingly (i.e. informed breeding dispersal). We demonstrated that stochastic variability in environmental conditions and habitat quality can underpin dispersal behaviour in amphibians. Our study highlighted the mechanistic linkages between habitat change, movement behaviour and prospects for reproductive performance, which is critical for understanding how wild animals respond to rapid environmental change.

Wyoming↗
USGS2016

DNA and dispersal models highlight constrained connectivity in a migratory marine megavertebrate

Population structure and spatial distribution are fundamentally important fields within ecology, evolution, and conservation biology. To investigate pan-Atlantic connectivity of globally endangered green turtles ( Chelonia mydas ) from two National Parks in Florida, USA, we applied a multidisciplinary approach comparing genetic analysis and ocean circulation modeling. The Everglades (EP) is a juvenile feeding ground, whereas the Dry Tortugas (DT) is used for courtship, breeding, and feeding by adults and juveniles. We sequenced two mitochondrial segments from 138 turtles sampled there from 2006-2015, and simulated oceanic transport to estimate their origins. Genetic and ocean connectivity data revealed northwestern Atlantic rookeries as the major natal sources, while southern and eastern Atlantic contributions were negligible. However, specific rookery estimates differed between genetic and ocean transport models. The combined analyses suggest that post-hatchling drift via ocean currents poorly explains the distribution of neritic juveniles and adults, but juvenile natal homing and population history likely play important roles. DT and EP were genetically similar to feeding grounds along the southern US coast, but highly differentiated from most other Atlantic groups. Despite expanded mitogenomic analysis and correspondingly increased ability to detect genetic variation, no significant differentiation between DT and EP, or among years, sexes or stages was observed. This first genetic analysis of a North Atlantic green turtle courtship area provides rare data supporting local movements and male philopatry. The study highlights the applications of multidisciplinary approaches for ecological research and conservation.

Florida↗
USGS2023

Grizzly bear movement models predict habitat use for nearby populations

Conservation planning and decision-making can be enhanced by ecological models that reliably transfer to times and places beyond those where models were developed. Transferrable models can be especially helpful for species of conservation concern, such as grizzly bears ( Ursus arctos ). Currently, only four grizzly bear populations remain in the contiguous United States. We evaluated transferability of previously derived individual-based, integrated step selection functions (iSSFs) developed from GPS-collared grizzly bears in the Northern Continental Divide Ecosystem by applying them within the nearby Selkirk (SE), Cabinet-Yaak (CYE), and Greater Yellowstone Ecosystems (GYE). We simulated 100 replicates of 5000 steps for each iSSF in each ecosystem, summarized relative use into 10 equal-area classes for each sex, and overlaid GPS locations from bears in the SE, CYE, and GYE on resulting maps. Spearman rank correlations between numbers of locations and class rank were ≥ 0.96 within each study area, indicating models were highly predictive of grizzly bear space use in these nearby populations. Assessment of models using smaller subsets of data in space and time demonstrated generally high predictive accuracy for females. Although generally high across space and time, predictive accuracy for males was low within some watersheds and in summer within the SE and CYE, potentially due to seasonal effects, vegetation, and food assemblage differences. Altogether, these results demonstrated high transferability of our models to landscapes in the Northern Rocky Mountains, suggesting they may be used to evaluate habitat suitability and connectivity throughout the region to benefit conservation planning.

Idaho, Montana, Washington, Wyoming↗
USGS2017

High value of ecological information for river connectivity restoration

Context Efficient restoration of longitudinal river connectivity relies on barrier mitigation prioritization tools that incorporate stream network spatial structure to maximize ecological benefits given limited resources. Typically, ecological benefits of barrier mitigation are measured using proxies such as the amount of accessible riverine habitat. Objectives We developed an optimization approach for barrier mitigation planning which directly incorporates the ecology of managed taxa, and applied it to an urbanizing salmon-bearing watershed in Alaska. Methods A novel river connectivity metric that exploits information on the distribution and movement of managed taxon was embedded into a barrier prioritization framework to identify optimal mitigation actions given limited restoration budgets. The value of ecological information on managed taxa was estimated by comparing costs to achieve restoration targets across alternative barrier prioritization approaches. Results Barrier mitigation solutions informed by life history information outperformed those using only river connectivity proxies, demonstrating high value of ecological information for watershed restoration. In our study area, information on salmon ecology was typically valued at 0.8–1.2 M USD in costs savings to achieve a given benefit level relative to solutions derived only from stream network information, equating to 16–28% of the restoration budget. Conclusions Investing in ecological studies may achieve win–win outcomes of improved understanding of aquatic ecology and greater watershed restoration efficiency.

Alaska↗
USGS2016

Predicting animal home-range structure and transitions using a multistate Ornstein-Uhlenbeck biased random walk

The home‐range concept is central in animal ecology and behavior, and numerous mechanistic models have been developed to understand home range formation and maintenance. These mechanistic models usually assume a single, contiguous home range. Here we describe and implement a simple home‐range model that can accommodate multiple home‐range centers, form complex shapes, allow discontinuities in use patterns, and infer how external and internal variables affect movement and use patterns. The model assumes individuals associate with two or more home‐range centers and move among them with some estimable probability. Movement in and around home‐range centers is governed by a two‐dimensional Ornstein‐Uhlenbeck process, while transitions between centers are modeled as a stochastic state‐switching process. We augmented this base model by introducing environmental and demographic covariates that modify transition probabilities between home‐range centers and can be estimated to provide insight into the movement process. We demonstrate the model using telemetry data from sea otters ( Enhydra lutris ) in California. The model was fit using a Bayesian Markov Chain Monte Carlo method, which estimated transition probabilities, as well as unique Ornstein‐Uhlenbeck diffusion and centralizing tendency parameters. Estimated parameters could then be used to simulate movement and space use that was virtually indistinguishable from real data. We used Deviance Information Criterion (DIC) scores to assess model fit and determined that both wind and reproductive status were predictive of transitions between home‐range centers. Females were less likely to move between home‐range centers on windy days, less likely to move between centers when tending pups, and much more likely to move between centers just after weaning a pup. These tendencies are predicted by theoretical movement rules but were not previously known and show that our model can extract meaningful behavioral insight from complex movement data.

Ecology↗