Interactions between Climate and Nutrient Cycles on Forest Response to Global Change: The Role of Mixed Forests

Abstract

Forest ecosystems are undergoing unprecedented changes in environmental conditions due to global change impacts. Modification of global biogeochemical cycles of carbon and nitrogen, and the subsequent climate change are affecting forest functions at different scales, from physiology and growth of individual trees to cycling of nutrients. This review summarizes the present knowledge regarding the impact of global change on forest functioning not only with respect to climate change, which is the focus of most studies, but also the influence of altered nitrogen cycle and the interactions among them. The carbon dioxide (CO 2 ) fertilization effect on tree growth is expected to be constrained by nutrient imbalances resulting from high N deposition rates and the counteractive effect of increasing water deficit, which interact in a complex way. At the community level, responses to global change are modified by species interactions that may lead to competition for resources and/or relaxation due to facilitation and resource partitioning processes. Thus, some species mixtures can be more resistant to drought than their respective pure forests, albeit it depends on environmental conditions and species' functional traits. Climate change and nitrogen deposition have additional impacts on litterfall dynamics, and subsequent decomposition and nutrient mineralization processes. Elemental ratios (i.e., stoichiometry) are associated with important ecosystem traits, including trees' adaptability to stress or decomposition rates. As stoichiometry of different ecosystem components are also influenced by global change, nutrient cycling in forests will be altered too. Therefore, a re-assessment of traditional forest management is needed in order to cope with global change. Proposed silvicultural systems emphasize the key role of diversity to assure multiple ecosystem services, and special attention has been paid to mixed-species forests. Finally, a summary of the patterns and underlying mechanisms governing the relationships between diversity and different ecosystems functions, such as productivity and stability, is provided.Human appropriation of land and water for agriculture and other purposes; emission of extraneous compounds to the atmosphere and water, extraction of food, fuel, and fiber from natural ecosystems; and transport of species around the globe, have pervasively influenced Earth's climate, hydrology, biogeochemistry, land cover, and species diversity [6,7]. The Earth and its ecosystems are undergoing rapid global change, driven by natural and human-induced factors, that is expected to influence plant species' dominance and distribution, primary productivity, and nutrient cycles worldwide [5,8]. Demographic, economic, socio-political, cultural, scientific, and technological factors (i.e., indirect drivers) cause physical and biological changes (i.e., direct drivers) in ecosystems. Global change involves the simultaneous and rapid alteration of several key environmental parameters that control the dynamics of forests [9,1...

Neighbourhood diversity mitigates drought impacts on tree growth

“…Conversely, biodiversity has a positive effect on forest productivity (Duffy, Godwin, & Cardinale, ), as mixed‐species forest communities have been demonstrated to be more productive (Huang et al, ; Liang et al, ) and more consistent in productivity over time than monocultures (del Río et al, ; Jucker, Bouriaud, Avacaritei, & Coomes, ; Morin, Fahse, de Mazancourt, Scherer‐Lorenzen, & Bugmann, ; Schnabel et al, ), resulting in higher amounts of carbon stored above‐ and below‐ground in species‐rich forests (Liu et al, ). Yet, despite advances in our understanding of biodiversity–productivity relationships (BPRs), the role of biodiversity in mitigating adverse effects of climate change on the functioning of forest ecosystems remains controversial (Ammer, ; González de Andrés, ; Grossiord, ; Hisano, Chen, Searle, & Reich, ; Hisano, Searle, & Chen, ), making predictions of ecosystem responses to climate change challenging. For example, it has been shown that the strength of BPRs at the community scale was higher in forest types or at forest sites associated with adverse climatic conditions (Jucker et al, ; Paquette & Messier, ), but the opposite response was revealed for forest sites along a global precipitation gradient (Jactel et al, ).…”

Adaptation of Forest Trees to Rapidly Changing Climate

“…It is therefore important to determine whether the mortality of trees in drought-affected areas will be concentrated in specific competitive and climatic conditions because this determination will enable forest managers to effectively identify areas that are more vulnerable to drought. Large-scale, consistent monitoring of forest ecosystems plays a key role in preparing for the impact of extreme events on the stability of forests [18].…”

Coarse Woody Debris’ Invertebrate Community is Affected Directly by Canopy Type and Indirectly by Thinning in Mixed Scots Pine—European Beech Forests

“…In addition, modifying litterfall composition and production rate with thinning or changes in canopy type [20,56] could also modify CWD mesofauna communities, as they are also directly connected to litter communities and vice versa [57]. Under the current paradigm of moving from pure to mixed Scots pine-European beech forests in Europe [15,16], our results should be taken into account both from the biodiversity perspective and from the carbon and nutrient cycling perspective [2], as invertebrate communities influence CWD decay rates [9,[57][58][59]. Consequently, we recommend considering the ecological role of CWD mesofauna when planning silvicultural practices, particularly in mixed forests.…”