Carbon pools recover more quickly than plant biodiversity in tropical secondary forests

Abstract

Although increasing efforts are being made to restore tropical forests, little information is available regarding the time scales required for carbon and plant biodiversity to recover to the values associated with undisturbed forests. To address this knowledge gap, we carried out a meta-analysis comparing data from more than 600 secondary tropical forest sites with nearby undisturbed reference forests. Above-ground biomass approached equivalence to reference values within 80 years since last disturbance, whereas below-ground biomass took longer to recover. Soil carbon content showed little relationship with time since disturbance. Tree species richness recovered after about 50 years. By contrast, epiphyte richness did not reach equivalence to undisturbed forests. The proportion of undisturbed forest trees and epiphyte species found in secondary forests was low and changed little over time. Our results indicate that carbon pools and biodiversity show different recovery rates under passive, secondary succession and that colonization by undisturbed forest plant species is slow. Initiatives such as the Convention on Biological Diversity and REDDþ should therefore encourage active management to help to achieve their aims of restoring both carbon and biodiversity in tropical forests.

Factors explaining variability in woody above-ground biomass accumulation in restored tropical forest

“…We did not observe any changes over time nor effects of our different restoration treatments on soil C. This result is not surprising given (1) the relatively short interval of time between our measurements (five years); (2) the fact that soil C changes more slowly than aboveground biomass, particularly in higher elevation rain forests (Paul et al, 2002;Marín-Spiotta and Sharma, 2013;Martin et al, 2013); and (3) the large size of the existing C pool makes it difficult to detect changes (Marín-Spiotta et al, 2008). Past reviews have reported inconsistent changes in soil C with transitions from pasture to broad-leaved tree plantations (Guo and Gifford, 2002;Martin et al, 2013). This may be due to the fact that pasture grasses, which are shaded out in plantations and secondary forests, can have a strong positive effect on soil C (Silva et al, 2013).…”

“…Given that tropical forest clearing comprises at least 12% of carbon emissions (van der Werf et al, 2009), there is an increasing focus on the role that forest recovery may play in sequestering carbon as part of efforts to reduce emissions from deforestation and forest degradation (REDD+, Edwards et al, 2010;Elias and Lininger, 2010;Harvey et al, 2010). This interest is clearly demonstrated by the large number of studies that have monitored the amount of C sequestered in both aboveground biomass and soil carbon in both tropical forest plantations and naturally regenerating tropical forests (Bonner et al, 2013;Marín-Spiotta and Sharma, 2013;Martin et al, 2013).…”

Restoring forests: What constitutes success in the twenty-first century?

“…Many areas that had been converted to agriculture have since been afforested while intensive management practices, such as surface mining and road construction, yield extremely harsh environments that make restoration difficult. Increasing public concern about ecological sustainability requires that restoration counteract environmental impacts, while simultaneously restoring forest species, rehabilitating structure and function, and enhancing carbon sequestration capacity and other ecosystem services of the land (SER 2004;Martin et al 2013;IUCN and WRI 2014;Cunningham et al 2015).…”

Lecciones ecológicas de la historia amazónica: impacto diferencial del uso del suelo en las estructuras y biomasas aéreas de bosques secundarios en Napo, Ecuador

“…Pero (c): la densidad puede recuperarse con cierta rapidez gracias a la colonización desde la matriz circundante y la formación de claros (comparando con Pitman et al 2001y Baker et al 2004. Todo eso puede ayudar a explicar por qué hay ecosistemas forestales tropicales cuyo recobro tarda 50-80 años (Martin et al 2014), en lugar de aprox. 25 años (Guariguata y Ostertag 2001): los disturbios recurrentes por el uso probablemente retardaron la acumulación de área basal y biomasa detectados por Martin et al (2014).…”

“…Todo eso puede ayudar a explicar por qué hay ecosistemas forestales tropicales cuyo recobro tarda 50-80 años (Martin et al 2014), en lugar de aprox. 25 años (Guariguata y Ostertag 2001): los disturbios recurrentes por el uso probablemente retardaron la acumulación de área basal y biomasa detectados por Martin et al (2014).…”