Utilize este identificador para referenciar este registo: http://hdl.handle.net/10400.5/2692
Título: Subsidy or stress ? Tree structure and growth in wetland forests along a hydrological gradient in South Europe
Autor: Rodriguez-Gonzalez, Patricia Maria
Stella, John Christopher
Campelo, Filipe
Ferreira, Maria Teresa
Albuquerque, António
Palavras-chave: Alnus glutinosa
functional traits
Salix atrocera
soil waterlogging
vegetative strategy
Data: 2010
Editora: Elsevier
Citação: "Forest Ecology and Management" ISSN 0378-1127. 259 (2010) 2015-2025
Resumo: In forested wetlands, hydrology exerts complex and sometimes compensatory influences on tree growth. This is particularly true in semi-arid ecosystems, where water can be both a limiting resource and a stressor. To better understand these relationships, we studied hydrologic and edaphic controls on the density, growth, tree architecture and overall productivity of forested wetlands dominated by the tree species Alnus glutinosa and Salix atrocinerea in Southern Europe. We sampled 49 plots set within 21 stands in the Atlantic coastal zone of the Iberian Peninsula, and quantified woody composition, size structure (diameter and height), and radial growth using dendrochronology. Plots were grouped into three saturation classes to compare tree growth characteristics (tree density, degree of sprouting, live basal area and productivity) across levels of saturation. We used Principal Component Analysis (PCA) to create integrated explanatory factors of hydrology, soil nutrient status and soil texture for use in linear mixed models to predict stand characteristics. Increased site saturation favoured a shift in species dominance from Alnus to Salix and resulted in a higher degree of multi-stemmed tree architecture (‘shrubbiness’), particularly for Alnus. Radial growth was negatively correlated with long-term soil saturation; however, annual productivity on a per-tree basis varied by species. Alnus growth and tree density were negatively correlated with waterlogging and fine-textured soils, possibly due to anaerobiosis in the rooting zone. In contrast, Salix growth was more influenced by nutrient limitation. Overall site productivity as measured by annual basal area increment decreased with prolonged saturation. In summary, soil saturation appears to act as a chronic stressor for tree species in this ecosystem. However, these species persist and maintain a dominant canopy position in the most permanently flooded patches through increased sprouting, albeit at a reduced rate of overall biomass accumulation relative to well-drained sites. The diversity in functional responses among wetland forest species has important implications for the conservation and management of these ecosystems. The sustainable management of these ecosystems is directly tied to their vulnerability to changing hydrological conditions. Non-equilibrium modifications to the hydrologic regime from land use and climate change, which are particularly severe in semi-arid regions, may further decrease productivity, integrity and resilience in these stress-adapted communities.
Peer review: yes
URI: http://hdl.handle.net/10400.5/2692
ISSN: 0378-1127
Versão do Editor: www.elsevier.com/locate/foreco
Aparece nas colecções:CEF - Artigos de Revistas

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