Restoration of ecosystem services in tropical forests: A global meta-analysis

Abstract

To reverse the effects of deforestation, tropical areas have expanded restoration efforts in recent years. As ecological restoration positively affects the structure and function of degraded ecosystems, understanding to what extent restoration recovers ecosystem services (ES) is an important step in directing large-scale restoration actions. We evaluated the effect of restoration in increasing the provision of ES in tropical forests. We performed a global meta-analysis of ecological indicators of the ES provided in restored areas, degraded areas and reference ecosystems. We tested for the effects of different restoration strategies, different types of degradation and for the effects of restoration over time. Overall, restoration actions contributed to a significant increase in levels of ecological indicators of ES (carbon pool, soil attributes and biodiversity protection) compared to disturbed areas. Among the restoration strategies, the natural regeneration was the most effective. Biodiversity protection and carbon recovered better than soil attributes. All other restoration strategies recovered ES to a substantially lesser degree, and reforestation with exotics decreased the ES of areas degraded by agriculture. In areas degraded by pasture, restoration was more effective in recovering the biodiversity protection, whereas in areas degraded by agriculture, the restoration recovered mainly the carbon pool. Our results show that by choosing the correct strategy, restoration can recover much of the ES lost by the degradation of tropical forests. These results should be considered for large-scale conservation and management efforts for this biome.

Fig 1. Flow diagram of database searching and article screening.

The checklist of the total Prisma 2009 requirements is in S2 Table.

Fig 2. Effect size (average and bootstrap CI) of ecosystem services recovered in restoration areas, according to restoration strategies.

(A) All ecosystem degradation types; (B) Degradation by pasture; (C) Degradation by agriculture. The vertical line represents the null hypothesis. Positive effect size means that the amount of ES in restored areas is higher than in degraded area.

Fig 3. Effect size (average and bootstrap CI) of ecosystem services recovered in restoration areas, according to different types of services (soil attributes, carbon pool and biodiversity protection).

(A) All ecosystem degradation types; (B) Degradation by pasture; (C) Degradation by agriculture. The vertical line represents the null hypothesis. Positive effect size means that the amount of ES in restored areas is higher than in degraded area.

Fig 4. Meta-regression of age of restored ecosystem and the effect size of different ecosystem services.

(A) Soil attributes (n = 150); (B) Carbon pool (n = 13); (C) Biodiversity protection (n = 71). Positive effect size means that the amount of ES in restored areas is higher than in degraded area. Three outlier was removed from (B).