DOI: 10.5061/dryad.g6g3416
title: Data from: Regional variation in interior Alaskan boreal forests is driven by fire disturbance, topography, and climate

description: High latitude regions are warming rapidly with important ecological and
 societal consequences. Utilizing two landscape-scale datasets from
 interior Alaska, we compared patterns in forest structure in two regions
 with sharply differing fire disturbance, topography, and climate. Our goal
 was to evaluate a set of hypotheses concerning possible warming-driven
 changes in forest structure suggested by recent literature. We found
 essentially consistent habitat associations for the tree flora across two
 disparate study areas concomitant with considerable differences in
 observed patterns of forest structure and composition. Our results
 confirmed expected increases in broadleaved species occupancy and
 abundance in the warmer, more fire-affected study region along with
 considerably higher tree occupancy and abundance in high elevation areas
 there. However, contrary to our predictions, we found no evidence of
 expected reductions in conifer occupancy or increases in non-fire related
 tree mortality. Instead, both individual and combined tree species
 occupancy, density, abundance, and richness were considerably higher in
 the warmer, more fire-influenced region, except in the warmest, driest
 areas (steep and south-facing slopes at low elevation). Our comparison of
 two landscape-scale datasets suggests that changes in tree distribution
 and forest structure in interior Alaska will proceed unevenly, governed by
 a mosaic of site-dependent influences wherein forest community composition
 and species dominance will shift along different trajectories and at
 different rates according to variation in underlying landscape attributes.
 Although there were clear differences in forest structure between the two
 areas that were likely attributable to differences in growing season
 warmth and fire disturbance, we found scant support for the concept of an
 incipient, ongoing biome shift in interior Alaska resulting from impending
 diminution of boreal forest cover over the short to medium term. Indeed,
 we suggest that (depending on severity of disturbance dynamics and the
 rapidity of future warming) cooler areas of interior Alaska’s forest may
 reasonably be expected to sustain marginal increases in forest cover with
 additional warming, at least in certain topographic positions (such as
 poorly drained basins and cool treeline sites) and/or geographic regions,
 prior to any landscape-scale diminution of forest cover due to warming.
description: YCNP_tree_model_data_1This MS Excel file contains primary response and covariate data used to build models of tree species occupancy and abundance in Yukon-Charley Rivers National Preserve.YCNP_tree_model_2This MS Excel file contains additional covariate data used to build models of tree species live occupancy and abundance in Yukon-Charley Rivers National Preserve.Mortality_data_for_models_YCNP_vs_DNPPThis MS Excel file contains primary response and covariate data used to build models of tree species morality patterns in Yukon-Charley Rivers National Preserve and Denali National Park and Preserve, Alaska.