Functional responses and resilience of boreal forest ecosystem after reduction of deer density

PLoS One. 2014 Feb 28;9(2):e90437. doi: 10.1371/journal.pone.0090437. eCollection 2014.

Abstract

The functional trait-based approach is increasingly used to predict responses of ecological communities to disturbances, but most studies target a single taxonomic group. Here, we assessed the resilience of a forest ecosystem to an overabundant herbivore population by assessing changes in 19 functional traits for plant, 13 traits for ground beetle and 16 traits for songbird communities after six years of controlled browsing on Anticosti Island (Quebec, Canada). Our results indicated that plants were more responsive to 6 years of reduced browsing pressure than ground beetles and songbirds. However, co-inertia analysis revealed that ground beetle communities responded in a similar way than plant communities with stronger relationships between plant and ground beetle traits at reduced deer density, a pattern not detected between plant and songbird. High deer density favored plants species that reproduce vegetatively and with abiotic pollination and seed dispersal, traits implying little interaction with animal. On the other hand, traits found at reduced deer density mostly involved trophic interaction. For example, plants in this treatment had fleshy fruits and large seeds dispersed by birds or other animals whereas ground beetle species were carnivorous. Overall, our results suggest that plant communities recovered some functional components to overabundant herbivore populations, since most traits associated with undisturbed forests were reestablished after six years of deer reduction. The re-establishment of functional plant communities with traits involving trophic interaction induces changes in the ground-beetle trait community, but forest structure remains likely insufficiently heterogeneous to shift the songbird trait community within six years.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Analysis of Variance
  • Animal Distribution / physiology
  • Animals
  • Coleoptera / physiology*
  • Deer / physiology*
  • Ecosystem
  • Islands
  • Plant Dispersal / physiology
  • Population Dynamics
  • Quebec
  • Reproduction
  • Seeds / anatomy & histology
  • Seeds / physiology*
  • Songbirds / physiology*
  • Trees / physiology*

Grants and funding

Funding for this research was provided by the Natural Sciences and Engineering Research Council of Canada (NSERC)-Produits Forestiers Anticosti Industrial Chair (SDC), the Québec Ministry of Natural Resources and Wildlife, NSERC discovery grants (MP, SP), as well as NSERC and Québec Centre for Biodiversity Science (QCBS) scholarships (MB). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.