Evaluating forest subcanopy response to moderate severity disturbance and contribution to ecosystem-level productivity and resilience

FOREST ECOLOGY AND MANAGEMENT

卷:376

Article

Fahey, Robert T.^1,2  Stuart-Haentjens, Ellen J.³  Gough, Christopher M.³  De La Cruz, Aubrie⁴  Stockton, Elizabeth⁴  Vogel, Christoph S.⁴  Curtis, Peter S.⁵ 

[1] Univ Connecticut, Dept Nat Resources & Environm, Storrs, CT USA

[2] Ctr Environm Sci & Engn, Storrs, CT USA

[3] Virginia Commonwealth Univ, Dept Biol, Richmond, VA 23284 USA

[4] Univ Michigan, Biol Stn, Ann Arbor, MI 48109 USA

[5] Ohio State Univ, Dept Evolut Ecol & Organismal Biol, Columbus, OH 43210 USA

关键词: Intermediate disturbance;    Northern hardwood;    Ecological silviculture;    Quercus rubra;    Acer rubrum;    Great Lakes region;   

DOI  :  10.1016/j.foreco.2016.06.001

来源: Elsevier

【 摘 要 】

North American temperate forests have functioned as a terrestrial carbon (C) sink for more than a century, but the future of this sink is highly uncertain as disturbance frequency increases and regrown forests approach maturity. The subcanopy is integral to the functional recovery of forests, supporting short-term resilience of primary production and longer-term shifts in tree species composition and diversity. However, the factors that contribute to variation in forest subcanopy response to disturbance are not well understood. In this study, we investigated subcanopy shifts in aboveground wood net primary productivity (ANPP(w)) and composition following experimental moderate severity disturbance emulating natural canopy mortality from age-related senescence. We assessed the importance of variation in disturbance severity, site fertility, and community composition on subcanopy disturbance response and contribution to total (canopy and subcanopy) ANPPP(w) response. We also assessed the effect of the moderate severity disturbance on species composition and diversity, and competitive patterns within the subcanopy layer. Subcanopy aboveground biomass and ANPP(w) increased substantially relative to pre-disturbance levels by a factor of 1.4 and 22.7, respectively. The subcanopy (stems <8 cm DBH) made up a large component of overall (canopy plus subcanopy) post disturbance ANPP(w) (16.2%) and disturbance response (post-disturbance ANPP(w)/pre-disturbance ANPP(w); 54.1%). Subcanopy ANPP(w), subcanopy post-disturbance ANPP(w) response, and subcanopy contribution to total post-disturbance ANPP(w) response were all most strongly predicted by subcanopy community composition in combination with canopy composition and site fertility. Variation in disturbance severity was not a strong predictor of subcanopy ANPP(w) response to disturbance. Subcanopy compositional trends and growth patterns both indicate likely increased heterogeneity in canopy composition (greater beta diversity) and a potential shift toward greater dominance by mid-tolerant Quercus rubra (northern red oak). Our results illustrate the importance of the subcanopy in the response of forest productivity to moderate severity disturbance and illustrate that composition of the subcanopy layer exerts a strong influence on the growth response both of the subcanopy and the forest as a whole. Our findings highlight the unique role of moderate severity disturbance, relative to more severe disturbances, in promoting biological and structural heterogeneity in forest ecosystems and favoring underrepresented mid-tolerant species. (C) 2016 Elsevier B.V. All rights reserved.

【 授权许可】

Free