Abstract
Background and aims: Investments in restoring native vegetation must increasingly allow for likely impacts of climate change, requiring re-evaluation of limits to ecological recovery and persistence. Nutrient enrichment and weed invasion are significant limits to restoration in mesic ecosystems, but in a drying climate, limits could shift towards more fundamental ecosystem functions. We used a state and transition framework to identify landuse-related changes in topsoil biophysical characteristics likely to influence climate resilience in mesic temperate eucalypt woodlands.
Methods: We compared topsoil condition in little-modified ‘reference’ states of the native ground-layer (dominated by tall tussock grasses) with four degraded ground-layer states identified in our state and transition framework. We hypothesized that ‘nutrient-depleted’ states (dominated by short tussock grasses) and ‘nutrient-enriched’ states (dominated by exotic annuals) would exhibit characteristics reflecting increased and decreased ecosystem vulnerability to a drying climate respectively.
Results: Our hypothesis that nutrient-depleted states are more vulnerable to a drying climate was supported by their significantly slower soil-water infiltration rates and significantly lower levels of topsoil carbon, clay, micro-invertebrates, microbial activity and modeled water holding capacity than reference states. However, degradation was less pronounced beneath trees, and our prediction regarding enriched states was supported only for carbon.
Conclusions: Topsoil biophysical characteristics associated with different ground-layer states are predictable using a state and transition framework. Climate resilience of nutrient-depleted states appears compromised by topsoil biophysical degradation, indicating increasing need for attention in mesic ecosystems predicted to become drier under climate change.
Original language | English |
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Pages (from-to) | 231-244 |
Number of pages | 14 |
Journal | Plant and Soil |
Volume | 383 |
Issue number | 1-2 |
DOIs | |
Publication status | Published - Oct 2014 |
Externally published | Yes |