Broadening the migratory portfolio of altitudinal migrants

Denryter, Kristin; Stephenson, Thomas R.; Monteith, Kevin L.

doi:10.1002/ecy.3321

Cited by 11 publications

(41 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Trajectories encompassed either one, multiple, or no round-trips. Making one or more round-trips away from the summer range might allow animals to better exploit resources or avoid unfavorable conditions [ 47 ]. However, leaving a familiar range is inherently risky, and the risk increases with the number of round-trips taken [ 48 ].…”

Section: Methodsmentioning

confidence: 99%

“…Deer that visited the same range during each of their trips were classified as commuters , whereas poly-migrants traveled to different ranges. Commuting between two ranges might allow animals to optimally exploit resources in both ranges, whereas making multiple round-trips to different ranges allow the animal to use resources in even more ranges, but at the cost of traversing more unfamiliar and potentially riskier terrain [ 47 ].…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Variation in movement patterns of mule deer: have we oversimplified migration?

et al. 2021

View full text Add to dashboard Cite

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.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Variation in movement patterns of mule deer: have we oversimplified migration?

et al. 2021

View full text Add to dashboard Cite

show abstract

“…Variation in the timing of SNBS migration between years (Spitz et al, 2018) suggests that SNBS are responding to inter-annual environmental variability based on proximate cues. The existence of vacillating migration in SNBS, where individuals undertake 2-4 movements between seasonal ranges during the migratory window (Denryter et al, 2021b), also suggests that migration is a response to observed intraannual variability. Memory may be the cognitive mechanism that underlies migration in predictable environments, while perception facilitates migration when the timing and location of resources, risks, and conditions is variable.…”

Section: Perception and Memorymentioning

confidence: 99%

“…We integrated multiple sources of positional data into our analysis including GPS, VHF, visual survey and capture information. Spitz et al (2018) also used elevation-based net squared displacement to classify migration and chose to categorize individuals that exhibit vacillating or abbreviated migration (Denryter et al, 2021b) as residents. These same individuals are classified as migrants in our study because of their presence below the elevational cutoff during the migratory window.…”

Section: Individual Historymentioning

confidence: 99%

“…In species such as mule deer (Odocoileus hemionus) (Sawyer et al, 2019) and caribou (Rangifer tarandus) (Dalerum et al, 2007), migration is a fixed, innate behavior arising from genetics or maternal effects (Møller et al, 2011;Pulido, 2011). However, migration can also be a conditional strategy with individuals exhibiting behavioral plasticity in response to changes in their internal state and external environment, as observed in moose (Alces alces) (Ball et al, 2001;Singh et al, 2012), roe deer (Capreolus capreolus) (Cagnacci et al, 2011), pronghorn (Antilocapra americana) (White et al, 2007), and bighorn sheep (Spitz et al, 2018;Denryter et al, 2021b). Behaviorally plastic migrants make a series of choices with respect to their migratory movements.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Seeing Is Be-Leaving: Perception Informs Migratory Decisions in Sierra Nevada Bighorn Sheep (Ovis canadensis sierrae)

et al. 2022

Self Cite

View full text Add to dashboard Cite

Seasonal migration is a behavioral response to predictable variation in environmental resources, risks, and conditions. In behaviorally plastic migrants, migration is a conditional strategy that depends, in part, on an individual’s informational state. The cognitive processes that underlie how facultative migrants understand and respond to their environment are not well understood. We compared perception of the present environment to memory and omniscience as competing cognitive mechanisms driving altitudinal migratory decisions in an endangered ungulate, the Sierra Nevada bighorn sheep (Ovis canadensis sierrae) using 1,298 animal years of data, encompassing 460 unique individuals. We built a suite of statistical models to partition variation in fall migratory status explained by cognitive predictors, while controlling for non-cognitive drivers. To approximate attribute memory, we included lagged attributes of the range an individual experienced in the previous year. We quantified perception by limiting an individual’s knowledge of migratory range to the area and attributes visible from its summer range, prior to migrating. Our results show that perception, in addition to the migratory propensity of an individual’s social group, and an individual’s migratory history are the best predictors of migration in our system. Our findings suggest that short-distance altitudinal migration is, in part, a response to an individual’s perception of conditions on alterative winter range. In long-distance partial migrants, exploration of migratory decision-making has been limited, but it is unlikely that migratory decisions would be based on sensory cues from a remote target range. Differing cognitive mechanisms underpinning short and long-distance migratory decisions will result in differing levels of behavioral plasticity in response to global climate change and anthropogenic disturbance, with important implications for management and conservation of migratory species.

show abstract

Diverse migratory portfolios drive inter‐annual switching behavior of elk across the Greater Yellowstone Ecosystem

et al. 2023

View full text Add to dashboard Cite

A growing body of evidence shows that some ungulates alternate between migratory and nonmigratory behaviors over time. Yet it remains unclear whether such short‐term behavioral changes can help explain reported declines in ungulate migration worldwide, as opposed to long‐term demographic changes. Furthermore, advances in tracking technology reveal that a simple distinction between migration and nonmigration may not sufficiently describe all individual behaviors. To better understand the dynamics and drivers of ungulate switching behavior, we investigated 14 years of movement data from 361 elk in 20 herds across the Greater Yellowstone Ecosystem (GYE). First, we categorized yearly individual behaviors using a clustering algorithm that identified similar migratory tactics across a continuum of behaviors. Then, we tested seven hypotheses to explain why some ungulates switch behaviors, and we evaluated how behavioral changes affected the proportions of different behaviors across the system. We identified four distinct behavioral tactics: residents (4.8% of elk‐years), short‐distance migrants (53.7%), elevational migrants (21.9%) and long‐distance migrants (19.6%). Of the 20 herds, 18 were partially migratory, and 5 had all four movement tactics present. We observed switches between migratory tactics in all sets of consecutive years during our study period, with an average of 22.5% of individual elk changing movement tactics from one year to the next. Elk in herds with higher movement tactic diversity were significantly more likely to switch tactics and often responded more effectively to adverse environmental conditions, compared to those in herds with low movement tactic diversity. During our study period, switching increased the prevalence of both short‐ and long‐distance migrants, decreased the prevalence of elevational migrants, and had no effect on the prevalence of residents. Our findings suggest that rather than contributing to the declining migratory behavior found in the GYE, switching behavior may enable greater resiliency to continuously changing environmental and anthropogenic conditions.

show abstract

Broadening the migratory portfolio of altitudinal migrants

Cited by 11 publications

References 16 publications

Variation in movement patterns of mule deer: have we oversimplified migration?

Variation in movement patterns of mule deer: have we oversimplified migration?

Seeing Is Be-Leaving: Perception Informs Migratory Decisions in Sierra Nevada Bighorn Sheep (Ovis canadensis sierrae)

Diverse migratory portfolios drive inter‐annual switching behavior of elk across the Greater Yellowstone Ecosystem

Contact Info

Product

Resources

About