Managing tree species diversity and ecosystem functions through coexistence mechanisms

Abstract

& Key message A better transfer to managers of studies examining the functional role of tree species diversity would be achieved by explicitly addressing two missing links: the effect of management interventions on coexistence mechanisms and the relationships between coexistence mechanisms and ecosystem functions. & Context Plant species diversity has been shown to promote a wide array of ecosystem functions and ecosystem services. However, scientific results concerning relationships between species diversity or species mixing and ecosystem functions have not been well transferred to management practices so far. Part of the problem lies in the difficulty of assessing whether interesting species mixtures can persist over the long term and how management influences ecosystem functions. & Aims We argue that a better transfer of knowledge to managers would be achieved by addressing two missing links: (i) the effect of management interventions on coexistence mechanisms and (ii) the relationships between coexistence mechanisms and ecosystem functions. & Methods To do so, we first provide a brief overview of the recent scientific results on relations between tree diversity (or twospecies mixing) and ecosystem functions, focusing on studies dealing with productivity and stability in forests. We further introduce the key question of whether mixed stands are transient or permanent. We then briefly present key elements of modern coexistence theory and illustrate them with three examples in forest ecosystems. We finish by discussing how management interventions in forests can affect coexistence mechanisms and by addressing some methodological perspectives. & Results We provide examples of management actions (e.g. gap-based silviculture, preferentialselection of the most frequent species, preferential selection of the most competitive species, plantingweakly competitive species) that may increase the strength of coexistence mechanisms. & Conclusion Analysing long-term management impacts on species coexistence and ecosystem functions with a combination of long-term monitoring of large permanent plots and mechanistic dynamic model simulations will be useful to develop relevant practices favouring mixed forests in the long term.

Bias in the detection of negative density dependence in plant communities

“…CNDD is also reported to be generally stronger than HNDD in forests and grasslands, which would facilitate coexistence (Adler et al ). The growing prominence and maturation of this work has now led to the first call to develop forest management practices that take advantage of CNDD (Cordonnier et al ).…”

Managing mixed stands can mitigate severe climate change impacts on ecosystem functioning

“…One interesting conclusion of our study is that the targeted composition was not necessarily the final composition, indicating that some mixed stands are more difficult to manage than others (Bauhus et al, 2017;Cordonnier et al, 2018). For example, in "stable management", a significant part of simulations did not reach the targeted species composition after 150 years (Fig.…”

“…With simulation-based studies, it is possible to have a comprehensive view of the stand development over time and on processes driving observed patterns, in the range of applicability of the model of course. More generally, to deal with the high uncertainty characterizing future climate, forest models appear as a key tool to test various scenarios (Cordonnier et al, 2018, Morin et al, 2020, complementing empirical and experimental approaches.…”

“…Stand management can be an efficient tool to mitigate the negative impacts of intensive droughts and promoting forest adaptation (Millar et al, 2007), through controlling density (Trouvé et al, 2017) or structural heterogeneity (Cordonnier et al, 2018a) including species mixing. It is however difficult to anticipate the combined effect of climate change and management on the long-term maintenance of species mixing in forest stands as well as the resulting effect on forest functioning (Cordonnier et al, 2018).…”

Traços funcionais e <i>performance</i> de espécies arbóreas em uma Floresta Ombrófila Mista no Planalto Sul-Catarinense

“…Estudos ao longo do tempo que procuram compreender a demografia de espécies arbóreas são subsídio para a adoção de estratégias silviculturais e de manejo de florestas naturais, com enfoque na conservação, recuperação e uso sustentável (CORDONNIER et al, 2018). Neste sentido, dentre as abordagens que permitem um maior entendimento sobre o tema, destacam-se aquelas que investigam como a performance das espécies arbóreas, representadas por suas taxas demográficas, são influenciadas por seus respectivos traços funcionais (POORTER et al, 2008).…”