Habitat fragmentation is linked to cascading effects on soil functioning and CO 2 emissions in Mediterranean holm-oak-forests

PeerJ

article

Dulce Flores-Rentería¹  Ana Rincón³  Teresa Morán-López²  Ana-Maria Hereş⁵  Leticia Pérez-Izquierdo³  Fernando Valladares²  Jorge Curiel Yuste⁶ 

[1] Group of Sustainability of Natural Resources and Energy;LINCGlobal, Department of Biogeography and Global Change;Department of Soil, Plant and Environmental Quality, Instituto de Ciencias Agrarias;Ecotono Lab, INIBIOMA, CRUB, Universidad Nacional del Comahue;Department of Forest Sciences, Transilvania University of Brasov;BC3-Basque Centre for Climate Change, Scientific Campus of the University of the Basque Country;Department of Biology and Geology, Universidad Rey Juan Carlos;IKERBASQUE, Basque Foundation for Science

关键词: Structural equation models;    Quercus ilex;    Soil functioning;    Forest fragmentation;   

DOI  :  10.7717/peerj.5857

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

We studied key mechanisms and drivers of soil functioning by analyzing soil respiration and enzymatic activity in Mediterranean holm oak forest fragments with different influence of the agricultural matrix. For this, structural equation models (SEM) were built including data on soil abiotic (moisture, temperature, organic matter, pH, nutrients), biotic (microbial biomass, bacterial and fungal richness), and tree-structure-related (basal area) as explanatory variables of soil enzymatic activity and respiration. Our results show that increased tree growth induced by forest fragmentation in scenarios of high agricultural matrix influence triggered a cascade of causal-effect relations, affecting soil functioning. On the one hand, soil enzymatic activity was strongly stimulated by the abiotic (changes in pH and microclimate) and biotic (microbial biomass) modifications of the soil environment arising from the increased tree size and subsequent soil organic matter accumulation. Soil CO2 emissions (soil respiration), which integrate releases from all the biological activity occurring in soils (autotrophic and heterotrophic components), were mainly affected by the abiotic (moisture, temperature) modifications of the soil environment caused by trees. These results, therefore, suggest that the increasing fragmentation of forests may profoundly impact the functioning of the plant-soil-microbial system, with important effects over soil CO2 emissions and nutrient cycling at the ecosystem level. Forest fragmentation is thus revealed as a key albeit neglected factor for accurate estimations of soil carbon dynamics under global change scenarios.

【 授权许可】

CC BY