Renato Crouzeilles

A global meta-analysis on the ecological drivers of forest restoration success

Two billion ha have been identified globally for forest restoration. Our meta-analysis encompassing 221 study landscapes worldwide reveals forest restoration enhances biodiversity by 15–84% and vegetation structure by 36–77%, compared with degraded ecosystems. For the first time, we identify the main ecological drivers of forest restoration success (defined as a return to a reference condition, that is, old-growth forest) at both the local and landscape scale. These are as follows: the time elapsed since restoration began, disturbance type and landscape context. The time elapsed since restoration began strongly drives restoration success in secondary forests, but not in selectively logged forests (which are more ecologically similar to reference systems). Landscape restoration will be most successful when previous disturbance is less intensive and habitat is less fragmented in the landscape. Restoration does not result in full recovery of biodiversity and vegetation structure, but can complement old-growth forests if there is sufficient time for ecological succession.

Moment of truth for the Cerrado hotspot

Despite projections of a severe extinction event, a window of opportunity is now open for a mix of policies to avoid biodiversity collapse in the Cerrado hotspot.

Ecological restoration success is higher for natural regeneration than for active restoration in tropical forests

Natural forest recovery is an effective ecological alternative to tree planting in tropical forests under certain conditions. Is active restoration the best approach to achieve ecological restoration success (the return to a reference condition, that is, old-growth forest) when compared to natural regeneration in tropical forests? Our meta-analysis of 133 studies demonstrated that natural regeneration surpasses active restoration in achieving tropical forest restoration success for all three biodiversity groups (plants, birds, and invertebrates) and five measures of vegetation structure (cover, density, litter, biomass, and height) tested. Restoration success for biodiversity and vegetation structure was 34 to 56% and 19 to 56% higher in natural regeneration than in active restoration systems, respectively, after controlling for key biotic and abiotic factors (forest cover, precipitation, time elapsed since restoration started, and past disturbance). Biodiversity responses were based primarily on ecological metrics of abundance and species richness (74%), both of which take far less time to achieve restoration success than similarity and composition. This finding challenges the widely held notion that natural forest regeneration has limited conservation value and that active restoration should be the default ecological restoration strategy. The proposition that active restoration achieves greater restoration success than natural regeneration may have arisen because previous comparisons lacked controls for biotic and abiotic factors; we also did not find any difference between active restoration and natural regeneration outcomes for vegetation structure when we did not control for these factors. Future policy priorities should align the identified patterns of biophysical and ecological conditions where each or both restoration approaches are more successful, cost-effective, and compatible with socioeconomic incentives for tropical forest restoration.

Increasing strict protection through protected areas on Brazilian private lands

A key strategy to reduce habitat loss and fragmentation involves the establishment of protected areas (PAs). Worldwide, c. 13% of land lies within PAs, but only 6% is subject to the more restrictive International Union for the Conservation of Nature (IUCN) categories I-IV. Private PAs may contribute to this figure, but require general guidance principles for their management. The Brazilian ‘Private Natural Heritage Reserves’ (RPPNs) constitute an example of good PA management, employing seven principles that should guide the creation of all private PAs. RPPNs have legal status and long-term security, allow only for indirect human uses, and provide a strategic conservation role in highly fragmented landscapes by improving connectivity. However, RPPNs are virtually absent from the World Database on Protected Areas, and given Brazils continental size, and the considerable and increasing number of RPPNs in Brazil, this omission has the potential to skew accurate quantification of the area of land subject to strict protection. The RPPN model can make an important contribution to the discussion of the role of private PAs in conservation, especially in the tropics.

The use of native vegetation as a proxy for habitat may overestimate habitat availability in fragmented landscapes

ContextNative vegetation is often used as a proxy for habitat to estimate habitat availability in landscapes. This approach may lead to incorrect estimates of the impacts of habitat loss and fragmentation on species, which have not been thoroughly quantified so far.ObjectivesWe quantified to what extent the loss of native vegetation reflect actual habitat loss by native species in landscapes. We tested the hypothesis that habitat availability declines at greater rates than native vegetation and thus is overestimated when it is quantified on the basis of native vegetation.MethodsUsing simulations, we quantified how the loss of native vegetation in artificial and real landscapes affects habitat availability for species with different habitat requirements. We contrasted a generalist species, which uses all native vegetation, with 10 habitat-specialist species classified into three categories (interior, patchy and riparian species).ResultsHabitat availability generally declined at greater rates than native vegetation for all specialist species. This pattern was apparent for different specialist species in a broad range of landscape types. Interior species always lost habitat availability more rapidly than the generalist species. Most riparian species lost habitat availability more rapidly than the generalist species. Responses of patchy species were more complex, depending on their dispersal abilities and landscape structure.ConclusionsHabitat availability is likely to be overestimated when native vegetation is used as proxy for habitat, because habitat availability will generally decline at greater rates than native vegetation. Therefore, a species-centered approach should be adopted when estimating habitat availability in landscapes.

Hard times for the Brazilian environment

To the Editor — In the midst of a severe political and ethical crisis, Brazil has suffered several setbacks for environmental conservation. Over the past few months, eagerness to climb out of recession through short-term economic gains combined with the political need to accommodate the powerful Agribusiness Parliamentary Front (40% of the Brazilian Congress) has resulted in a set of bills that will soften environmental licensing1, suspend the ratification of indigenous lands2, and reduce protection of 600,000 ha of Amazon and Atlantic Forest3. Additionally, on 11 July, President Michel Temer passed a law that permits ‘land thieves’ to legalize their land holdings easily and cheaply4. These changes could not come at a worse time. Data produced in the past two months show that Brazil has experienced an alarming increase in annual deforestation rates. Despite efforts in the past decade to reduce deforestation, high-resolution remote-sensing-derived land-cover classifications5 estimate that between 2006 and 2015 Brazil has lost 30 Mha of natural vegetation — aggregation of 13 land cover classes of forests, savannahs, native grasslands and wet ecosystems, covering all six Brazilian biomes. Between 2015 and 2016 deforestation in the Atlantic Forest biodiversity hotspot, already 88% deforested, reached the highest level in 10 years (29,100 ha), an increase of 60% over the last year6, while in the Amazon it increased 29% (789,800 ha), the highest in the past eight years7. This picture is even worse within the other Brazilian biodiversity hotspot, the Cerrado tropical savannah, which has already lost 88 Mha (46%) of its native vegetation. On 25 July, the government quietly announced that the Cerrado lost 948,300 ha of native vegetation in 2015, which was 52% higher than the Amazon deforestation for the same year8. If deforestation maintains the same rate (~1% per year), the Cerrado could lose 1,140 plant species in the next 30 years, a number eight times more species than the number known to have gone extinct worldwide since 15009. These alarming deforestation rates across Brazilian biomes have generated consequences that go beyond biodiversity loss and reduction in the provision of ecosystem services, such as carbon storage. On 22 June, the Norwegian Government, the major financier of the Amazon Fund, which is the main funder of actions to prevent, monitor, and combat deforestation in the Amazon, officially informed Brazil that they will halve investment in 2017 or even suspend financial assistance if the new upward trend of deforestation is confirmed in the coming months10. Now that the US has announced it will withdraw from the Paris Climate Agreement, Brazil is expected to play a leading role in environmental negotiations, together with China, South Africa and India. However, while Brazil is starting to build policies to implement its climate commitments, such as recovering 12 Mha of native vegetation11, these recent environmental setbacks go against global environmental policies Brazil ratified and puts its chances of combatting deforestation at risk. Brazil will only overcome these hard times when environmental conservation becomes a public policy priority again.

Planning protected areas network that are relevant today and under future climate change is possible: the case of Atlantic Forest endemic birds

Background A key strategy in biodiversity conservation is the establishment of protected areas. In the future, however, the redistribution of species in response to ongoing climate change is likely to affect species’ representativeness in those areas. Here we quantify the effectiveness of planning protected areas network to represent 151 birds endemic to the Brazilian Atlantic Forest hotspot, under current and future climate change conditions for 2050. Methods We combined environmental niche modeling and systematic conservation planning using both a county and a regional level planning strategy. We recognized the conflict between biodiversity conservation and economic development, including socio-economic targets (as opposed to biological only) and using planning units that are meaningful for policy-makers. Results We estimated an average contraction of 29,500 km2 in environmentally suitable areas for birds, representing 52% of currently suitable areas. Still, the most cost-effective solution represented almost all target species, requiring only ca. 10% of the Atlantic Forest counties to achieve that representativeness, independent of strategy. More than 50% of these counties were selected both in the current and future planned networks, representing >83% of the species. Discussion Our results indicate that: (i) planning protected areas network currently can be useful to represent species under climate change; (ii) the overlapped planning units in the best solution for both current and future conditions can be considered as “no regret” areas; (iii) priority counties are spread throughout the biome, providing specific guidance wherever the possibility of creating protected area arises; and (iv) decisions can occur at different administrative spheres (Federal, State or County) as we found quite similar numerical solutions using either county or regional level strategies.