DOI: 10.5061/dryad.tx95x69tq
title: Science to inform policy: linking population dynamics to habitat for a threatened species in Canada

description: Abstract 1. Boreal forests provide numerous ecological services, including
 the ability to store large amounts of carbon, and are of significance to
 global biodiversity. Increases in industrial activities in boreal
 landscapes since the mid-20th century have added to concerns over
 biodiversity loss and climate change. Boreal forests are home to dwindling
 populations of boreal caribou (Rangifer tarandus caribou) in Canada, a
 species at risk that requires large, undisturbed landscapes for
 persistence. In 2012, the Canadian government defined critical habitat for
 boreal caribou by relating calf recruitment to disturbances. Some have
 questioned whether the recruitment-relationship can be extrapolated beyond
 the environmental conditions represented in the analysis. 2. We examined
 the effects of human disturbances and fire (alone and in combination) on
 variation in recruitment and adult female survival using data from 58
 study areas in Canada. Top models were used in aspatial scenarios of
 landscape change to evaluate the efficacy of the critical habitat
 definition in achieving the recovery objectives for boreal caribou in two
 contrasting landscapes: Little Smoky, dominated by high levels of human
 disturbances, and SK1, dominated by fire. 3. The top recruitment model
 suggested the negative effect of fire was 3-4 times smaller than human
 disturbances. The top adult female survival model included human
 disturbances only. These results re-affirm that human disturbances are the
 primary factor contributing to boreal caribou declines. 4. Our aspatial
 scenarios suggested that undisturbed habitat would have to increase to
 ≥68% for Little Smoky to maintain a self-sustaining population of boreal
 caribou with some degree of certainty. In contrast, the SK1 population was
 self-sustaining with 40% undisturbed habitat when fire disturbance
 predominates, but could become vulnerable with increases in human
 disturbances (8–9%). 5. Policy implications: Our results suggest that the
 65% undisturbed critical habitat designation may serve as a reasonable
 proxy for achieving boreal caribou recovery in landscapes dominated by
 human disturbances. However, some populations may be less or more
 vulnerable, as illustrated by the SK1 scenarios. Continued population
 monitoring will be essential to assessing the effectiveness of land
 management strategies developed for boreal caribou recovery, especially
 with climate change.
description: Estimates of disturbance were calculated for 58 study areas with
 demographic data on boreal caribou. We derived estimates of anthropogenic disturbances,
 buffered by 500 m, from maps prepared by Environment and Climate Change
 Canada (Environment Canada, 2011; Pasher et al., 2013; Environment and
 Climate Change Canada, 2018). Provincial and territorial jurisdictions
 provided the fire data. Fire disturbance was characterized as unbuffered
 areas burnt 40 years prior to the first year of available demographic data
 used in the analyses.
description: Variable names correspond to those described in Table 1 of the
 journal article.