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Across the western United States, many ungulate herds must migrate seasonally to access resources and avoid harsh winter conditions. Because these migration paths cover vast landscapes (in other words migration distances up to 150 miles [241 kilometers]), they are increasingly threatened by roads, fencing, subdivisions, and other development. Over...
Contexts in source publication
Context 1
... Flat mule deer inhabit the foothills southwest of Challis, adjacent to the Salmon River in winter ( fig. 8). After the snow melts, mule deer migrate to the southwest. The western migration crosses rural areas of the Salmon River Mountains, with some deer traveling through the Sawtooth Valley to summer range in the Sawtooth Mountains. On average, Centennial Flat mule deer migrate more than 30 mi (48 km) between summer and winter ranges. The ...
Context 2
... deer in the southern Wyoming Range population winter north of Evanston in the relatively low mountains between Kemmerer, Wyoming, and Woodruff Narrows Reservoir along the Utah border ( fig. 38). Many deer in this population migrate north more than 100 mi (161 km) to summer ranges in the Wyoming Range surrounding Afton, Wyoming. Migrations in this population are not limited to Wyoming, with at least one deer summering in the Caribou Range in Idaho. Challenges for this population include highway and train mortality, especially ...
Citations
... Using and citing publicly available data is not required by NEPA but helps build trust and understanding with stakeholders in land-use planning processes (Sayer et al. 2013). In Colorado, terrestrial wildlife (eg mule deer [Odocoileus hemionus]) was the most commonly analyzed resource in BLM EAs, highlighting the importance of having current, publicly available spatial data on the presence and condition of big game populations and habitats (eg CPW 2020; Kauffman et al. 2020). For many other resources, publicly available data were cited infrequently (eg in one of 33 invasive plant sections). ...
Public land management agencies in the US are committed to using science‐informed decision making, but there has been little research on the types and topics of science that managers need most to inform their decisions. We used the National Environmental Policy Act to identify four types of science information needed for making decisions relevant to public lands: (1) data on resources of concern, (2) scientific studies relevant to potential effects of proposed actions, (3) methods for quantifying potential effects of proposed actions, and (4) effective mitigation measures. We then used this framework to analyze 70 Environmental Assessments completed by the Bureau of Land Management in Colorado. Commonly proposed actions were oil and gas development, livestock grazing, land transactions, and recreation. Commonly analyzed resources included terrestrial wildlife, protected birds, vegetation, and soils. Focusing research efforts on the intersection of these resources and actions, and on developing and evaluating the effectiveness of mitigation measures to protect these resources, could strengthen the science foundation for public lands decision making.
... Moreover, spatial memory of the migration route had an extraordinary influence on migration, affecting movements manifold stronger than tracking spring green-up or autumn snow depth [56], and was characterized by strong fidelity [13,44,58]. Such spatial memory along with resource tracking allowed deer to repeatedly use the same migratory routes of 820 km round-trip [56,59]. Consequentially, the loss of migratory traditions will thus expunge generations of knowledge about the locations of high-quality forage and likely suppress population abundance [10,12], and leave pockets of potential habitat unoccupied because of the lost memory of viable migratory routes [13]. ...
The huemul (Hippocamelus bisulcus) is endangered, with 1500 deer split into >100 subpopulations along 2000 km of Andes. Currently occupied areas are claimed-erroneously, to be critical prime habitats. We analyzed historical spatiotemporal behavior since current patterns represent only a fraction of pre-Columbian ones. Given the limited knowledge, the first group (n = 6) in Argentina was radio-marked to examine spatial behavior. Historically, huemul resided year-round in winter ranges, while some migrated seasonally, some using grasslands >200 km east of their current presence, reaching the Atlantic. Moreover, huemul anatomy is adapted to open unforested habitats, also corroborated by spotless fawns. Extreme naivety towards humans resulted in early extirpation on many winter ranges—preferentially occupied by humans, resulting in refugee huemul on surrounding mountain summer ranges. Radio-marked huemul remained in small ranges with minimal altitudinal movements, as known from other subpopulations. However, these resident areas documented here are typical summer ranges as evidenced by past migrations, and current usage for livestock. The huemul is the only cervid known to use mountain summer ranges year-round in reaction to anthropogenic activities. Losing migratory traditions is a major threat, and may explain their presently prevalent skeletal diseases, reduced longevity, and lacking recolonizations for most remaining huemul subpopulations.
... Widespread use of GPS collars, through programs like those associated with the US Department of the Interior Secretarial Order 3362, has made ungulate migration routes and key seasonal ranges widely available. For example, the US Geological Survey is now collaborating with state wildlife agencies to collate and provide access to ungulate migration and winter range data for the western US (Kauffman et al. 2020). Armed with these types of data, solar developers and regulators could improve USSE siting and design layouts to minimize impacts to ungulates. ...
Utility‐scale solar energy (USSE) has become an efficient and cost‐effective form of renewable energy, with an expanding footprint into rangelands that provide important habitat for many wild ungulate populations. Using global positioning system data collected before and after construction, we documented the potential impacts of USSE on pronghorn (Antilocapra americana), including direct habitat loss, indirect habitat loss, and barrier effects to both resident and migratory population segments. Our case study highlights the challenges that USSE poses to ungulate conservation, including (1) impermeable security fencing that blocks access to and reduces connectivity between formerly available habitats, and (2) the lack of guidelines for minimizing USSE impacts on ungulates. Improved siting and ungulate‐specific best management practices would help to minimize habitat loss and retain landscape connectivity. Ungulate biodiversity and ecosystem services (for example, services provided by long‐distance migratory species) in arid rangelands are important considerations when balancing the global benefits of renewable energy with local wildlife impacts.
... Data/Analysis/Ace) that informs, for example, conservation funding priorities (Wildlife Conservation Board 2019). Similarly, the Wyoming Migration Initiative created an atlas and database of ungulate migration routes throughout the state (Kauffman et al. 2020) to inform connectivity conservation action. ...
Ecosystem management and governance of cross-scale dependent systems require integrating knowledge about ecological connectivity in its multiple forms and scales. Although scientists, managers, and policymakers are increasingly recognizing the importance of connectivity, governmental organizations may not be currently equipped to manage ecosystems with strong cross-boundary dependencies. Managing the different aspects of connectivity requires building social connectivity to increase the flow of information, as well as the capacity to coordinate planning, funding, and actions among both formal and informal governance bodies. We use estuaries in particular the San Francisco Estuary, in California, in the United States, as examples of cross-scale dependent systems affected by many intertwined aspects of connectivity. We describe the different types of estuarine connectivity observed in both natural and human-affected states and discuss the human dimensions of restoring beneficial physical and ecological processes. Finally, we provide recommendations for policy, practice, and research on how to restore functional connectivity to estuaries.
... winter ranges [1][2][3]. The loss of migration routes can be detrimental to population and community structures as well as plant-herbivore dynamics [4]. ...
... Our results are mostly descriptive in nature and several patterns of movement illustrated herein lack a clear linkage to ecological significance. Based on previous examinations of migration in mule deer [2,23,32,36] and hypothesized patterns of cultural transmission from adult to offspring [5], we were expecting animals to use mostly typical patterns of movement (e.g., resident, onetime migrant, or one-time migrant with stop overs) and be consistent among years. Our results illustrate that there is considerable variation among individuals and plasticity within individuals that is not explained by a single overarching idea or concept (e.g., access to high quality food or reducing the risk of predation [4]). ...
... Variation and plasticity in migration strategies may be a mechanism to avoid a mismatch with weather conditions in fall and plant phenology in spring [23]. Although the tracking of plant phenology in spring, also known as green wave surfing [2], has mostly been studied in the context of typical migration, atypical patterns may emerge when migrants are unable to track phenology closely due to landscape barriers (such as rivers and roads), discontinuities in resources, or risks such as vulnerability to predation. However, Bischof et al. [8] point out that any appropriately timed movement between ranges with different phenological development can provide a nutritional benefit, even without exploiting the full potential of the green wave. ...
Background
Conservation and management of migratory animals has gained attention in recent years, but the majority of research has focused on stereotypical ‘migrant’ and ‘resident’ behaviors, often failing to incorporate any atypical behaviors or characterize migratory behaviors beyond distance and timing of the migration. With migration threatened by anthropogenic development and climate change, it is crucial that we understand the full range of migratory behaviors. Our objective was to demonstrate and characterize the variation in migration strategies, including typical and atypical migratory behaviors for mule deer (Odocoileus hemionus) in Utah, USA.
Methods
Because calculation of common metrics such as distance, timing, and use of stopovers during migration did not adequately describe the variation we observed in migratory behavior for this species—particularly when animals visited multiple (> 3) ranges for extended lengths of time—we developed additional methods and categories to describe observed variation in migratory behavior. We first categorized trajectories based on the number of discrete, separate ranges and range shifts between them. Then, we further characterized the variation in migration strategies by examining the timing, duration, and distance traveled within each of the categories. We also examined if and how frequently individual deer switched among categories from year to year.
Results
We classified 1218 movement trajectories from 722 adult female mule deer, and found that 54.4% were dual-range migrants, who made one round-trip to one distinct range. Multi-range migrants (23.6%) made one round-trip during which they stayed at multiple discrete ranges. Commuters (1.0%) traveled to the same range multiple times, and poly migrants (1.5%) made multiple round-trips to different ranges. Gradual movers (2.5%) did not show a discrete range shift but moved gradually between ranges, whereas residents (12.6%) never left their home ranges, and dispersers (4.4%) left but never returned. Of the deer that we monitored for multiple years, 51.2% switched among categories.
Conclusion
We conclude that the substantial number of atypical migratory strategies, as well as the number of deer that switched categories, underlines the importance of studying these less-stereotyped behaviors that may be exhibited by large proportions of populations. Acknowledging and investigating the full complexity and diversity in migratory strategies might uncover unknowns with respect to underlying factors and drivers of migration, and can help shape effective conservation strategies.
The Grand Portage Band of Lake Superior Chippewa manages for sustainable subsistence harvests of moose (mooz; Alces alces ) and white‐tailed deer (waawaashkeshi; Odocoileus virginianus ). Moose populations in northern Minnesota, USA, are declining, which may necessitate alterations to Indigenous subsistence practices. Moose and deer exhibit seasonal behaviors such as altered space use and movement strategies, to which gray wolves (ma'iingan; Canis lupus ) and humans may adapt, resulting in seasonal mortality patterns. Identifying periods of increased moose and deer vulnerability is important for achieving tribal conservation objectives. We assessed seasonal cause‐specific mortality of adult moose (2010–2021) and deer (2016–2022) fitted with global positioning system collars on and near the Grand Portage Indian Reservation (Gichi Onigaming; GPIR) in Minnesota and hypothesized mortality risk would be influenced by species‐specific space use patterns and weather. We estimated survival rates and mortality risk using time‐to‐event models. We recorded 42 moose mortalities (17 health issues, 8 predations, 4 subsistence harvests, 13 unknown causes) and 49 deer mortalities (26 predations, 13 harvests, 4 other causes, 6 unknown causes). Mean annual moose survival was 83.2%, and mortality risk peaked during late winter (~25 April) and fall (~8 October). Mean annual deer survival was 48.0%, and mortality risk peaked during late winter (~25 March) and during their fall migration period (~11 November). Mortality timing coincided with transitions between space use states (i.e., periods of spatial stability), suggesting ungulates are at greater risk during these transitional periods, though movement strategy (i.e., resident vs. migratory) did not influence mortality risk. Further, increased winter severity corresponded with increased deer mortality. We observed similar temporal peaks in mortality risk when harvest mortalities were censored, suggesting our observed seasonal mortality peaks occur naturally despite harvest comprising most fall deer mortality. Our results can inform population models and harvest regulations by identifying periods of mortality risk on GPIR under Anishinaabe principles of seventh‐generation conservation planning.
Conserving migratory ungulates relies on the analysis of GPS collar data and associated maps of migration corridors to inform management and policy actions. Current methods for identifying migratory corridors use complex statistical models designed to account for movement uncertainty rather than estimating the amount of space required by animals to migrate. Furthermore, such methods can complicate conservation efforts by producing highly variable corridor widths and non‐contiguous corridors that do not fully connect seasonal ranges.
To remedy, we propose an intuitive line buffer approach for delineating individual migration corridors that is simple to implement and focuses on the functional corridor widths needed by migratory ungulates.
By buffering a line that connects successive GPS locations, we can delineate individual migration corridors with consistent widths that are robust to variable parameters (GPS fix rate, travel speed, tortuosity) and provide contiguous connection between seasonal ranges. Using a combination of expert knowledge, simulation and 10‐min GPS collar data collected from mule deer (Odocoileus hemionus) and pronghorn (Antilocapra americana), we suggest 400–600 m are reasonable estimates of functional migration corridor widths for individuals of those species.
Synthesis and applications. Our line buffer approach is intended to simplify migration corridor delineation, improve transparency and encourage a broader discussion of functional corridor widths. These considerations help advance efforts to conserve habitat within migration corridors and prioritize conservation efforts within a single corridor or across multiple corridors.
Animal movement is the mechanism connecting landscapes to fitness, and understanding variation in seasonal animal movements has benefited from the analysis and categorization of animal displacement. However, seasonal movement patterns can defy classification when movements are highly variable. Hidden Markov movement models (HMMs) are a class of latent-state models well-suited to modeling movement data. Here, we used HMMs to assess seasonal patterns of variation in the movement of pronghorn (Antilocapra americana), a species known for variable seasonal movements that challenge analytical approaches, while using a population of mule deer (Odocoileus hemionus), for whom seasonal movements are well-documented, as a comparison. We used population-level HMMs in a Bayesian framework to estimate a seasonal trend in the daily probability of transitioning between a short-distance local movement state and a long-distance movement state. The estimated seasonal patterns of movements in mule deer closely aligned with prior work based on indices of animal displacement: a short period of long-distance movements in the fall season and again in the spring, consistent with migrations to and from seasonal ranges. We found seasonal movement patterns for pronghorn were more variable, as a period of long-distance movements in the fall was followed by a winter period in which pronghorn were much more likely to further initiate and remain in a long-distance movement pattern compared with the movement patterns of mule deer. Overall, pronghorn were simply more likely to be in a long-distance movement pattern throughout the year. Hidden Markov movement models provide inference on seasonal movements similar to other methods, while providing a robust framework to understand movement patterns on shorter timescales and for more challenging movement patterns. Hidden Markov movement models can allow a rigorous assessment of the drivers of changes in movement patterns such as extreme weather events and land development, important for management and conservation.
Highly mobile and migratory wildlife are ecologically, culturally, and economically important because they provide ecosystem services across heterogenous landscapes. Migratory ungulates (hoofed mammals) are particularly influential because of their large body size, seasonal movement across vast distances, and ties to human society. Ungulate migrations are widely declining in the face of habitat alteration, and initiatives across the globe seek to conserve them. However, migratory herds can generate significant costs or disservices for landowners and communities, complicating management and conservation. We demonstrate how a comprehensive assessment of the ecosystem services and disservices (ESDs) provided by mobile wildlife can enable conservation policy that facilitates coexistence across multi-use landscapes. Our mixed-methods approach applies the widely recognized Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) ESD categories as a framework to combine formal scientific knowledge spanning multiple disciplines with experiential knowledge gathered from local stakeholders through interviews. We apply this methodology in the context of the Greater Yellowstone Ecosystem (GYE), which harbors long-distance migrations of six ungulate species that move between public protected areas and private working lands. We discuss how stakeholder knowledge corroborates or contradicts scientific literature and characterize stakeholder groups and their perspectives. We suggest that formal assessments of ESDs within their ecological and socioeconomic contexts could mobilize resources for conservation, increase returns on conservation spending, and support conflict resolution amongst groups seeking to manage wildlife for different objectives.
Ungulates (hooved mammals) have a broad distribution across the western United States and play an important role in maintaining predator-prey dynamics, affecting vegetation communities, and providing economic benefits to regional communities through tourism and hunting. Throughout the diverse landscapes they occupy, many ungulate populations undertake seasonal migrations to exploit spatially and temporally variable resources and to avoid predation or other threats. As the human footprint continues to expand across the western United States, ungulates increasingly face more obstacles on their migratory journeys. These obstacles threaten the long-term persistence of existing migrations. As a result, wildlife management agencies across the western United States have worked to identify and protect (or enhance) ungulate migration corridors and seasonal ranges identified from global positioning system (GPS) collar data. These efforts garnered additional support through the U.S. Department of the Interior Secretarial Order (SO) 3362, which was initiated in 2018 and provided Federal support for enhancing habitat quality of big-game winter ranges and migration corridors across the western states.
Further, SO 3362 prompted the U.S. Geological Survey (USGS) to establish the Corridor Mapping Team (CMT): a collaboration between USGS and participating State and Federal wildlife management agencies, as well as numerous Tribal Nations. The CMT works collaboratively to map ungulate migrations and seasonal ranges throughout the western United States within the Ungulate Migrations of the Western United States report series. Volume 1 of the series was published in 2020 and contained migrations and winter ranges from 42 herds across 5 states. Volume 2 was published in 2022 and contained migrations and seasonal ranges from an additional 65 herds. This report, Volume 3 in the series, details migrations and seasonal ranges from an additional 45 herds throughout most western states. In aggregate, the report series has detailed and mapped the migrations and seasonal ranges of 152 ungulate herds and serves as a map-based inventory of the documented ungulate migrations across the western United States. The data layers for most of the herds included in the report series are also available to the public by the USGS. In addition to the included herd maps, this volume provides an overview of the many ways the mapping efforts associated with the CMT are being integrated into local conservation, management, and policy throughout the western United States.
