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Data from: Collapse, reorganization, and regime identity: breaking down past management paradigms in a forest-grassland ecotone

Citation

Donovan, Victoria et al. (2021), Data from: Collapse, reorganization, and regime identity: breaking down past management paradigms in a forest-grassland ecotone, Dryad, Dataset, https://doi.org/10.5061/dryad.mw6m905wm

Abstract

The identity of an ecological regime is central to modern resilience theory and our understanding of how systems collapse and reorganize following disturbance. However, resilience-based models used in ecosystem management have been criticized for their failure to integrate disturbance outcomes into regime identity. Assessments are needed to understand how well these classifications represent ecosystem responses that occur over management relevant time scales. We tracked post-wildfire forest and grassland dynamics 27 years after wildfire in eastern ponderosa pine savanna. We tested for differences between the assigned identity of a site (forest or grassland) versus classifications based on the site's disturbance history (burned/unburned and fire severity). Under current ecosystem models used to manage these forest-grassland ecotones, forests that experience high severity fire are expected to resemble an unburned grassland following fire, while forests and grasslands that experience low severity fire are expected to resemble unburned forests and grasslands, respectively. Twenty-seven years after wildfire, burned forests and grasslands displayed a high degree of departure from their expected regime identity. Plant and bird communities deviated significantly on sites that experienced low severity fire from undisturbed sites classified under the same ecological regime (grassland or forest). Forest sites that experienced high severity fire were the most unique of all disturbance history classes. Our results demonstrate that structures and communities predicted under resilience-based models used for eastern ponderosa pine management do not emerge over management relevant time scales following disturbance. Over 20% of variation in ecological structures and communities was explained by a single, 27-year-old disturbance. Integrating disturbance legacies will help improve applied models of ecosystem dynamics.

Methods

Data were measured across and adjacent to a mixed severity wildfire perimeter that occurred in 1989 in western Nebraska in a matrix of eastern ponderosa pine forest and grassland. Sampled sites included unburned grassland, burned grassland, unburned ponderosa pine forest, ponderosa pine forest that burned at low severity, and ponderosa pine forest that burned at high severity, indicated in the data set by the 'Burn_Class' column. Sampling locations were distributed in a stratified-random design. A full and detailed description of sampling techniques and design can be found in the data's corresponding manuscript.

Usage Notes

This data set contains:

(1) Live ponderosa pine tree data (Live_PP_Data), including the number of trees per site and tree diameter at breast height (DBH)

(2) Snag data, including the number of snags per site, snag decay class, and DBH

(3) Bird community data

(4) Shrub data, including species cover and height

(5) Coarse Woody Debris (CWD) data recorded as the length of a transect line covered by CWD

(6) Herbaceous Community data, including species cover

 

Funding

USDA NIFA, McIntire Stennis, Award: 1008861

USDA NIFA, McIntire Stennis, Award: 1008861