10.5061/DRYAD.1758MF7B
Minckley, Thomas A.
University of Wyoming
Shriver, Robert K.
University of Wyoming
Shuman, Bryan N.
Shuman, B
University of Wyoming
Data from: Resilience and regime change in a southern Rocky Mountain
ecosystem during the past 17000 years
Dryad
dataset
2012
Pinus contorta
Lake Level
Abies bifolia
Regime Change
Holocene
Picea engelmannii
Artemisia
Charcoal
2012-02-14T16:58:03Z
2012-02-14T16:58:03Z
en
https://doi.org/10.1890/11-0283.1
119923 bytes
1
CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
Paleoecological records indicate that subalpine forests in western North
America have been resilient in response to multiple influences, including
severe droughts, insect outbreaks, and widely varying fire regimes, over
many millennia. One hypothesis for explaining this ecosystem resilience
centers on the disruption of forest dynamics by frequent disturbance and
climatic variability, and the resulting development of non- steady-state
regimes dominated by early-succession conifers with broad climatic
tolerances, such as lodgepole pine (Pinus contorta var. latifolia Engelm.
ex Wats.). To evaluate this hypothesis, we independently reconstructed the
vegetation, fire, and effective-moisture histories of a small, forested
watershed at 2890-m elevation in southeastern Wyoming, using sedimentary
pollen and charcoal counts in conjunction with sedimentary lake-level
indicators. The data indicate that prominent vegetation shifts (from
sagebrush steppe to spruce-fir parkland at ca. 10.7 ka and spruce-fir
parkland to pine-dominated forest at ca. 8.5 ka) coincided with changes in
effective moisture. However, after lodgepole pine forests established at
ca. 8.5 ka, similar hydroclimatic changes did not produce detectable
vegetation responses. Fire history data show that other aspects of the
ecosystem were responsive to changes in effective moisture at centennial
timescales with prolonged fire-free episodes coinciding with periods of
low effective moisture ca. 7.2-5.6 and 3.7-1.6 ka. Throughout our record,
the ratio of ecosystem perturbation time (i.e., fire frequency and changes
in effective moisture) to recovery time (assuming 200-600 year
successional processes) falls within estimates of the ratio for non-steady
state ecosystems. Frequent perturbations, therefore, may have prevented
this ecosystem from reaching compositional equilibrium with the varied
climatic conditions over the past 8.5 ka. Equilibrium states could have
included more abundant spruce (Picea spp.) and fir (Abies spp.) than
presently observed based on brief increases in pollen abundances of these
taxa during prolonged dry, fire-free intervals. Our results show that
although current climate changes favor widespread disturbance in Rocky
Mountain forests, the composition of these ecosystems could be highly
resilient and recover through successional dynamics over the next few
decades to centuries.
LWHPollen09Excel file with depths and ages of samples, and percentage
values for all taxa identified. Data may also be found on the NOAA
paleclimatology website for fossil and modern pollen:
http://www.ncdc.noaa.gov/paleo/pollen.htmlLWH CHAR RAWExcel File
containing raw charcoal counts for Little Windy Hill Pond. Data are
related to drive depth (of core), absolute depth, age of sample, charcoal
counts, and macrofossils identified.
Rocky Mountains