A meta‐analysis of functional group responses to forest recovery outside of the tropics

Abstract

Both active and passive forest restoration schemes are used in degraded landscapes across the world to enhance biodiversity and ecosystem service provision. Restoration is increasingly also being implemented in biodiversity offset schemes as compensation for loss of natural habitat to anthropogenic development. This has raised concerns about the value of replacing old‐growth forest with plantations, motivating research on biodiversity recovery as forest stands age. Functional diversity is now advocated as a key metric for restoration success, yet it has received little analytical attention to date. We conducted a meta‐analysis of 90 studies that measured differences in species richness for functional groups of fungi, lichens, and beetles between old‐growth control and planted or secondary treatment forests in temperate, boreal, and Mediterranean regions. We identified functional‐group–specific relationships in the response of species richness to stand age after forest disturbance. Ectomycorrhizal fungi averaged 90 years for recovery to old‐growth values (between 45 years and unrecoverable at 95% prediction limits), and epiphytic lichens took 180 years to reach 90% of old‐growth values (between 140 years and never for recovery to old‐growth values at 95% prediction limits). Non‐saproxylic beetle richness, in contrast, decreased as stand age of broadleaved forests increased. The slow recovery by some functional groups essential to ecosystem functioning makes old‐growth forest an effectively irreplaceable biodiversity resource that should be exempt from biodiversity offsetting initiatives.

Quantifying the impacts of grassland restoration on biodiversity and ecosystem services in China: A meta-analysis

“…In the meantime, conflicts can arise over the recovery process (Spake et al, 2015). As shown in our results, grassland restoration was partially successful in achieving reference conditions, as the biodiversity was 17.34% lower than the reference state and ecosystem services were 28.07% lower than that of reference grassland.…”

Species turnover (β‐diversity) in ectomycorrhizal fungi linked to uptake capacity

“…Ectomycorrhizal fungal species recruitment into these mid‐age stands will also likely continue for some decades (Spake et al . ), and stochastic processes may also govern the inclusion of late‐seral EcM fungal species (Gao et al . ).…”

Meta‐analysis of management effects on biodiversity in plantation and secondary forests of Japan

“…Although functional groups within broad taxonomic groupings vary in their responses to forest management impacts (Spake et al, 2015), low sample sizes forced their grouping into broad taxonomic classifications, which may have obscured differences in responses of finer classifications. Although functional groups within broad taxonomic groupings vary in their responses to forest management impacts (Spake et al, 2015), low sample sizes forced their grouping into broad taxonomic classifications, which may have obscured differences in responses of finer classifications.…”

“…Whilst their strict protection represents a conservation priority in the face of forest loss and degradation worldwide, the biodiversity potential of disturbed planted and secondary forests is widely acknowledged (Putz et al, 2012). Although several syntheses of this vast literature exist, they have limited potential for practicable recommendations across a range of contexts, because of their tendency towards narrative synthesis over quantitative metaanalysis and a focus on charismatic taxa and tropical regions (Spake, Martin, Ezard, Newton, & Doncaster, 2015), or their inclusion of studies published only in English (Amano, González-Varo, & Sutherland, 2016). Although several syntheses of this vast literature exist, they have limited potential for practicable recommendations across a range of contexts, because of their tendency towards narrative synthesis over quantitative metaanalysis and a focus on charismatic taxa and tropical regions (Spake, Martin, Ezard, Newton, & Doncaster, 2015), or their inclusion of studies published only in English (Amano, González-Varo, & Sutherland, 2016).…”

“…Planted forest area is increasing globally, having risen from 4 to 7% of total forest area between 1990 and 2015. Principal management interventions for enhancing biodiversity in temperate plantations include disturbance by stand thinning to enhance the natural regeneration of native trees, and rotation age extension, on the premise that many species are dependent on later successional stages (Spake et al, 2015). Plantations generally lack the continuity and structural attributes typical of old-growth forests, giving rise to the moniker of "green deserts" (Koh & Gardner, 2010); however, their habitat quality can vary in relation to management activities (Humphrey, 2005).…”