Abstract
Global climate warming is one of the key forces driving plant community shifts, such as range shifts of temperate species into boreal forests. As plant community shifts are slow to observe, ecotones, boundaries between two ecosystems, are target areas for providing early evidence of ecological responses to warming. The role of soil fauna is poorly explored in ecotones, although their positive and negative effects on plant species can influence plant community structure. We studied nematode communities in response to experimental warming (ambient, +1.7, +3.4 °C) in soils of closed and open canopy forest in the temperate-boreal ecotone of Minnesota, USA and calculated various established nematode indices. We estimated species-specific coverage of understory herbaceous and shrub plant species from the same experimental plots and tested if changes in the nematode community are associated with plant cover and composition. Individual nematode trophic groups did not differ among warming treatments, but the ratio between microbial-feeding and plant-feeding nematodes increased significantly and consistently with warming in both closed and open canopy areas and at both experimental field sites. The increase in this ratio was positively correlated with total cover of understory plant species, perhaps due to increased predation pressure on soil microorganisms causing higher nutrient availability for plants. Multivariate analyses revealed that temperature treatment, canopy conditions and nematode density consistently shaped understory plant communities across experimental sites. Our findings suggest that warming-induced changes in nematode community structure are associated with shifts in plant community composition and productivity in the temperate-boreal forest ecotones.
Original language | English (US) |
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Pages (from-to) | 713-723 |
Number of pages | 11 |
Journal | Oecologia |
Volume | 175 |
Issue number | 2 |
DOIs | |
State | Published - Jun 2014 |
Bibliographical note
Funding Information:Acknowledgments We thank cindy buschena for the logistic help. We also thank Winfried Voigt for his suggestions in multivariate analysis. nico eisenhauer acknowledges funding by the Deutsche Forschungsgemeinschaft (DFG; ei 862/1). Madhav P. Thakur and nico eisenhauer acknowledge funding by the DFG in the framework of the emmy noether research group (ei 862/2). The b4WarmeD project has been funded by the Us Department of energy (grant no. De-FG02-07er64456), the college of Food, agricultural and natural resource sciences at the University of Minnesota, and the Minnesota environment and natural resources Trust Fund. We acknowledge helpful reviewer comments which improved our paper considerably.
Keywords
- Climate change
- Plant parasitic index
- Plant-soil feedback
- Range shifts
- Trophic groups