Major dams and the challenge of achieving “No Net Loss” of biodiversity in the tropics

Abstract

Dam construction is booming across tropical regions critical for global biodiversity and ecosystem service provision. The principle of “No Net Loss” (NNL)—under which biodiversity impacts of development projects are quantified and fully mitigated—is being increasingly applied to large infrastructure development worldwide, including dams. We discuss the impacts of major tropical dams and associated implementation of NNL policies and outline three major challenges in achieving NNL: (1) overcoming practicalities implementing NNL in highly connected river systems over large spatio‐temporal scales; (2) the stakes are high if NNL fails because tropical regions are hyper‐diverse, rich in species endemism, and difficult to restore; and (3) inclusion of ecosystem services in NNL design is necessary due to the importance of tropical biodiversity for ecosystem service provision at multiple spatial scales. Overcoming these challenges is crucial when hundreds of dams are planned and under construction across the tropics, many potentially subject to NNL policies.

The Role of “No Net Loss” Policies in Conserving Biodiversity Threatened by the Global Infrastructure Boom

“…74 Application of avoidance can also be suppressed by governments if they perceive strong geopolitical incentives to promote infrastructure development. For example, dam construction in the Brazilian Amazon cannot be reconciled with achieving NNL in biodiversity; 12,76,77 however, the government perceives access to hydroelectric energy to be a geopolitical priority that supersedes avoiding impacts to irreplaceable biodiversity. 78,79 Once the avoidance and minimization steps of the mitigation hierarchy have been applied, any residual impacts of infrastructure on biodiversity are then mitigated through offset policy, with any failures to apply the first two stages of the hierarchy adequately manifesting in additional residual impacts.…”

“…93 NNL may be intrinsically unfeasible for projects that damage invaluable or irreplaceable biodiversity. 26 NNL policies thus need to define ''no-go'' situations and ensure that these are integrated with, and do not undermine, existing strict protections (although in practice such protections are often over-ridden when projects are considered economic or political imperatives, e.g., dams in megadiverse tropical forest regions 76 ). It is necessary to enhance macro-scale avoidance through strengthening strategic environmental assessment by integrating development objectives and systematic conservation planning to clearly highlight where impacts to biodiversity must be avoided, such as in South Africa's planning policy and biodiversity offsetting implementation strategy.…”

Fires Drive Long-Term Environmental Degradation in the Amazon Basin

“…Despite its environmental importance, the Amazon has been exploited and degraded for decades as a result of the public policies imposed by the governments of the countries that share it. The forest and animals are being displaced by livestock, soybean plantations [5][6][7][8], land-reform projects [9], mining [10], hydroelectric constructions [11,12], and urbanization [13]. These rapid land use and land cover changes in the Amazon have recently been associated with an increase in greenhouse gas (GHG) emissions, mainly due to deforestation [14], in addition to the consequence of land use change on soil quality [15], such as declining soil organic carbon (SOC) [16,17].…”

Evaluating watershed health in Costa Rican national parks and protected areas

“…Corcovado NP alterations (Gierszewski et al 2020;Anderson et al 2006;Dynesisus and Nilsson 1994). It is also well documented that dams affect the distribution and abundance of aquatic biota, especially migratory species (Jones and Bull 2020;Pereira et al 2020). Additionally, an alarming and highly referenced climate model created by the University of Massachusetts-Climate System Research Center predicts that the Costa Rican high elevation Pacific slopes and the Caribbean lowlands are likely to receive 30% less precipitation within the next 50-100 years (Stan et al 2020;Castillo et al 2017;Karmalkar et al 2008).…”