Does a trade‐off between growth plasticity and resource conservatism mediate post‐fire shrubland responses to rainfall seasonality?

• Published in: The New phytologist Vol. 230; no. 4; pp. 1407 - 1420
• Main Authors: Blerk, Justin J., West, Adam G., Altwegg, Res, Hoffman, M. Timm
• Format: Journal Article
• Language: English
• Published: England Wiley Subscription Services, Inc 01.05.2021
• Subjects: Availability; climate change; Ecosystem; Fertility; fire; Fires; Fynbos; Growth rate; Mediterranean; Mineral nutrients; Moisture; Nutrient availability; phenotypic plasticity; Plastic properties; Plasticity; Rain; Rainfall; Recovery; Regrowth; resource conservatism; Seasonal variations; Seasonality; shrubland; Shrublands; Soil; Soil conservation; Soil fertility; soil nutrients; Soils; Species; Vegetation regrowth; soil nutrients; Mediterranean; rainfall; shrubland; fire; resource conservatism; phenotypic plasticity; climate change
• ISSN: 0028-646X; 1469-8137
• DOI: 10.1111/nph.17246

Summary Growth plasticity may allow fire‐prone species to maximize their recovery rates during temporary, sporadic periods of rainfall availability in the post‐fire environment. However, moisture‐driven growth plasticity could be maladaptive in nutrient‐limited environments that require tighter control of growth and resource use. We investigated whether a trade‐off between plasticity and conservatism mediates growth responses to altered rainfall seasonality in neighbouring shrubland communities that occupy different soils. We monitored post‐fire vegetation regrowth in two structurally similar, Mediterranean‐type shrublands for 3 years. We investigated the effects of experimentally altered rainfall seasonality on post‐fire species’ growth rates. We found that moisture‐driven growth plasticity was higher among species occupying the fertile soils of the renosterveld site relative to those occupying the nutrient‐poor soils of the fynbos site. This resulted in higher overall responsiveness of post‐fire recovery patterns in renosterveld to experimental shifts in rainfall seasonality. In post‐fire shrubland communities, the trade‐off between moisture‐dependent growth plasticity and resource conservatism could be mediated by soil nutrient availability. Therefore, edaphic differences between structurally similar shrublands could lead to differences in their sensitivity to post‐fire rainfall seasonality.