Data from: Recovery of a boreal ground-beetle (Coleoptera: Carabidae) fauna 15 years after variable retention harvest
Wu, Linhao; He, Fangliang; Spence, John (2020), Data from: Recovery of a boreal ground-beetle (Coleoptera: Carabidae) fauna 15 years after variable retention harvest, Dryad, Dataset, https://doi.org/10.5061/dryad.msbcc2fvq
1. Retention harvests are preferred over traditional clear-cuts for sustainable forest management because maintenance and re-establishment of native forest biodiversity is a priority. However, few studies have examined long-term responses of biotic assemblages to retention harvest at particular sites.
2. We studied the effects of decreasing initial harvest intensities (clear-cut, 10, 20, 50, and 75% dispersed green tree retention) on carabid beetle assemblages relative to assemblage changes in un-harvested control stands in four successionally ordered cover-types of boreal mixedwood forest. We also studied temporal effects by comparing assemblages over a 16-year pre- and post-harvest period, using data collected through monitoring of the EMEND (Ecosystem Management Emulating Natural Disturbance) experiment in NW Alberta, Canada.
3. Retention harvests affected assemblages differently across cover-types. Assemblages in compartments harvested in the earlier forest successional stages of ‘deciduous’ or ‘deciduous with spruce understory’ converged toward the pre-harvest structure of corresponding controls over time. In contrast, beetle assemblages in ‘mixed’ or ‘conifer’ compartments, that represent later successional forest, moved steadily away from their pre-harvest structures during the first post-harvest decade. These latter assemblages became strikingly more similar to those under deciduous canopies by 15 years post-harvest. Synthesis and applications. Variable retention harvests will promote and maintain biodiversity better than clear-cutting. Higher retention levels promote faster recovery, but toward fauna typical of early successional forest in all cover-types. Carabids associated with conifer habitats are less resistant to impact from harvesting than are those from broadleaf deciduous forest. Therefore, conifer dominated stands present the most significant management challenge and higher retention levels are required to promote rapid and effective faunal recovery in such late successional stands.
Ground-beetles were collected at the same sites in all EMEND compartments using pitfall traps in 1999, 2000, 2004, 2009 and 2014, with these years corresponding to 1, 2, 5, 10 and 15 years post-harvest, respectively. Pre-harvest sampling (1998) was more limited, but ground-beetles were also sampled more widely across the stands originally designated as replicate blocks for each cover-type.
Ground-beetles were pooled by compartment across each year's collection. Catches were standardized to number of individuals per 100 trap-days to minimize effects of occasional trap disturbance on the data.
Canonical Redundancy Analysis (RDA; Legendre and Legendre 2012) was used to assess the response of ground-beetle assemblage composition to three factors (time, cover-type, harvest treatment and their interactions).
EMEND Carabids abundance data (1998-2014)