Using seasonal landscape models to predict space use and migratory patterns of an arctic ungulate

Abstract Background Caribou in the Western Arctic Herd undertake one of the longest, remaining intact migrations of terrestrial mammals in the world. They are also the most important subsistence resource for many northern rural residents, who rely on the caribou’s migratory movements to bring them n...

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Main Authors: A. P. Baltensperger, K. Joly
Format: Article
Language:English
Published: BMC 2019-06-01
Series:Movement Ecology
Subjects:
Online Access:http://link.springer.com/article/10.1186/s40462-019-0162-8
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author A. P. Baltensperger
K. Joly
author_facet A. P. Baltensperger
K. Joly
author_sort A. P. Baltensperger
collection DOAJ
description Abstract Background Caribou in the Western Arctic Herd undertake one of the longest, remaining intact migrations of terrestrial mammals in the world. They are also the most important subsistence resource for many northern rural residents, who rely on the caribou’s migratory movements to bring them near for harvest. Migratory geography has never been static, but subsistence harvesters have reported recent shifts in migration away from areas where they traditionally occurred. The reasons behind these changes are not well-understood, but may be related to rapid climate change and anthropogenic disturbances. Methods To predict changes in distribution and shifting migratory areas over the past decade, we used GPS telemetry data from adult females to develop predictive ecological niche models of caribou across northwestern Alaska. We employed the machine-learning algorithm, TreeNet, to analyze interactive, multivariate relationships between telemetry locations and 37 spatial environmental layers and to predict the distributions of caribou during spring, calving season, insect-harassment season, late summer, fall, and winter from 2009 to 2017. Model results were analyzed to identify regions of repeated predicted use, quantify mean longitude, predict land cover selection, and track migratory changes over time. Results Distribution models accurately predicted caribou at a spatially-explicit, 500-m scale. Model analyses identified migratory areas that shifted annually across the region, but which predicted 4 main areas of repeated use. Niche models were defined largely by non-linear relationships with coastally-influenced, climatic variables, especially snow-free date, potential evapo-transpiration, growing season length, proximity to sea ice, winter precipitation and fall temperature. Proximity to roads and communities were also important and we predicted caribou to generally occur more than 20–100 km from these features. Conclusions Western Arctic Herd caribou were predicted to occur in warmer, snow-free and treeless areas that may provide conditions conducive for efficient travel and foraging. Rapidly changing seasonal climates and coastal influences that determine forage availability, and human impediments that slow or divert movements are related to geographically and phenologically dynamic migration patterns that may periodically shift caribou away from traditional harvest areas. An enhanced understanding of the geographic behavior of caribou over time could inform traditional harvests and help conserve important Western Arctic caribou migratory areas.
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spelling doaj.art-330fe3b330024f2da79647fdfe7f8dfe2022-12-21T18:58:51ZengBMCMovement Ecology2051-39332019-06-017111910.1186/s40462-019-0162-8Using seasonal landscape models to predict space use and migratory patterns of an arctic ungulateA. P. BaltenspergerK. JolyAbstract Background Caribou in the Western Arctic Herd undertake one of the longest, remaining intact migrations of terrestrial mammals in the world. They are also the most important subsistence resource for many northern rural residents, who rely on the caribou’s migratory movements to bring them near for harvest. Migratory geography has never been static, but subsistence harvesters have reported recent shifts in migration away from areas where they traditionally occurred. The reasons behind these changes are not well-understood, but may be related to rapid climate change and anthropogenic disturbances. Methods To predict changes in distribution and shifting migratory areas over the past decade, we used GPS telemetry data from adult females to develop predictive ecological niche models of caribou across northwestern Alaska. We employed the machine-learning algorithm, TreeNet, to analyze interactive, multivariate relationships between telemetry locations and 37 spatial environmental layers and to predict the distributions of caribou during spring, calving season, insect-harassment season, late summer, fall, and winter from 2009 to 2017. Model results were analyzed to identify regions of repeated predicted use, quantify mean longitude, predict land cover selection, and track migratory changes over time. Results Distribution models accurately predicted caribou at a spatially-explicit, 500-m scale. Model analyses identified migratory areas that shifted annually across the region, but which predicted 4 main areas of repeated use. Niche models were defined largely by non-linear relationships with coastally-influenced, climatic variables, especially snow-free date, potential evapo-transpiration, growing season length, proximity to sea ice, winter precipitation and fall temperature. Proximity to roads and communities were also important and we predicted caribou to generally occur more than 20–100 km from these features. Conclusions Western Arctic Herd caribou were predicted to occur in warmer, snow-free and treeless areas that may provide conditions conducive for efficient travel and foraging. Rapidly changing seasonal climates and coastal influences that determine forage availability, and human impediments that slow or divert movements are related to geographically and phenologically dynamic migration patterns that may periodically shift caribou away from traditional harvest areas. An enhanced understanding of the geographic behavior of caribou over time could inform traditional harvests and help conserve important Western Arctic caribou migratory areas.http://link.springer.com/article/10.1186/s40462-019-0162-8AlaskaCaribouClimateEcological niche modelInfrastructureMachine learning
spellingShingle A. P. Baltensperger
K. Joly
Using seasonal landscape models to predict space use and migratory patterns of an arctic ungulate
Movement Ecology
Alaska
Caribou
Climate
Ecological niche model
Infrastructure
Machine learning
title Using seasonal landscape models to predict space use and migratory patterns of an arctic ungulate
title_full Using seasonal landscape models to predict space use and migratory patterns of an arctic ungulate
title_fullStr Using seasonal landscape models to predict space use and migratory patterns of an arctic ungulate
title_full_unstemmed Using seasonal landscape models to predict space use and migratory patterns of an arctic ungulate
title_short Using seasonal landscape models to predict space use and migratory patterns of an arctic ungulate
title_sort using seasonal landscape models to predict space use and migratory patterns of an arctic ungulate
topic Alaska
Caribou
Climate
Ecological niche model
Infrastructure
Machine learning
url http://link.springer.com/article/10.1186/s40462-019-0162-8
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