Landscape conservation forecasting to evaluate ecological condition and wildlife habitat suitability in Eastern Nevada, USA

Introduction: Cooperation among managers of protected areas and federal
multiple use lands with private inholdings to increase restoration success
and economies of scale creates ecological and regulatory complexity best
studied with state-and-transition simulation models (STSM). Objectives:
Project partners asked whether (1) agency budgets are sufficient to lower
the dissimilarity between current vegetation and the reference condition,
(2) prescribed burning improves bighorn sheep habitat without excess
reduction of older subalpine forest classes, (3) vegetation treatments
reduce uncharacteristic fire activity, and (4) climate scenarios affect
vegetation treatments and bighorn sheep habitat? Methods: Spatial STSMs
were run for a 161,569-ha remote-sensed vegetation map. Partners selected
two management scenarios crossed with three 50-year climate projections
applied to 22 focal ecological systems with defined objectives, budgets,
treatments cost and success rates, and metrics for vegetation and bighorn
sheep. Results: Drier climate suppressed fire but its greater
precipitation variability increased fire and avalanche frequency.
Treatments decreased area burned at lower elevations where non-native
annual fuels facilitated fires. Ecological departure (vegetation
dissimilarity) from reference conditions was unchanged when lower
elevation seedings included introduced species, but ecological departure
decreased with native species seeding. Prescribed fire and increased
avalanche frequency increased bighorn sheep habitat suitability.
Implications for Practice: Treatment effectiveness increases by focusing
treatment resources on <15 ecological systems per landscape;
otherwise no single system is sufficiently funded. Prescribed fire at
subalpine elevation can be used to increase young forage for and habitat
suitability of bighorn sheep while temporally causing slight departure
from reference conditions. Reduction of heavy woody fuels and non-native
annual fuels at lower elevation followed by plant seedings reduced fire
frequency at lower elevations. Traditional ecological departure might not
be the best metric of success when introduced (i.e., non-native) species
seedings replace vegetation classes not found during pre-European
settlement as both equally contribute to ecological departure. Three
systems might not require treatments because they increased ecological
departure.