Steps to improve connectivity consideration in EIAs for road projects
Written By Larissa Oliveira Gonçalves, Andreas Kindel, Vinicius Augusto Galvão Bastazini & Fernanda Zimmermann Teixeira
24th November 2022
Road projects affect ecological connectivity for many species and ecosystems
One of the main effects of roads is the change in ecological connectivity. Road networks often pose barriers to the movement of organisms within and between populations, decreasing their access to resources and, consequently, their fitness. Roads can affect population abundance and persistence, and these effects can ripple through ecological communities, altering patterns of species composition, richness, and the interactions among them, ultimately affecting ecosystem functioning. Roads can also act as corridors by facilitating the movement of native species and the undesirable spread of invasive species.
Potential impacts on connectivity need to be better assessed in EIA
Environmental Impact Assessment (EIA) is one of the most important instruments to avoid or reduce the impacts of human infrastructure on wildlife. Unfortunately, landscape-scale effects are regularly neglected in EIAs of road projects worldwide, and even in countries that have regulation for EIA, ecological connectivity is assessed only superficially. While the maintenance of ecological corridors is usually briefly mentioned, there are no proper quantitative predictions and assessments of connectivity.
How to improve the connectivity evaluation in EIAs
In a recently published letter, we highlight 14 steps to advance the consideration of ecological connectivity in EIAs for road projects:
Recognize the importance of Strategic Environmental Assessments (SEA): ecological connectivity should be considered in multiple tiers.
Perform cumulative effects assessment: even a small and localized project can break regional connectivity and additive and synergic impacts from multiple activities and stressors should be recognized.
Recognize that sites with higher road mortality are not always located in sites with higher landscape connectivity: the proper recognition of the mechanisms behind the effect of interest is essential to recommend appropriate mitigation measures. Both reduced connectivity and increased mortality should be measured in distinct or associated ways
Move connectivity analyses from single species toward a multi-species approach: multi-species connectivity is important to safeguard complex networks of species interactions, ecosystem functioning, and biodiversity maintenance. There is a demand for the development of analytical methods capable of considering concomitantly the connectivity needs of multiple species of concern.
Select target species or groups as surrogates for assessing connectivity: these species can be used as indicators to infer how the loss of ecological connectivity caused by road projects will affect other species or biodiversity values.
Choose an appropriate spatial extent to perform ecological connectivity modelling: scale should be determined based on target groups and on the relevance of impacts of the road project. We encourage the consideration of multiscale and scale optimization analyses.
Recognize temporal scale and landscape dynamics: movement and connectivity patterns are not constant over time.
Validate connectivity models to ensure the use of the best decision-making tool: models that are not validated can result in inaccurate management decisions.
Follow the mitigation hierarchy, i.e., limit the negative impacts of development projects on biodiversity and ecosystem services by iteratively addressing four key actions: ‘avoid’, ‘minimize’, ‘restore’ and ‘offset’.
Target the principle of ‘no-net-loss’: residual losses should be counterbalanced. This requires the definition of what reference comparison for connectivity is being considered, what ecological outcomes should be monitored, and what should be targeted and acceptable in no-net policies.
Improve the follow-up stage: post-construction monitoring is paramount to validate model predictions, to assess mitigation effectiveness and to inform maintenance and adjustments needed in mitigation.
Follow the principles of adaptive management: decisions and adjustments should be made in response to new information including changes within the current project and in future projects.
Intensify the cooperation among researchers, EIA practitioners, road constructors, regulators, and other stakeholders: cooperation and co-production are essential to accelerate the implementation and adaptation of connectivity analyses to the complex process of EIAs at the project level.
Improve requirements and enforcement from different state and private agencies financing road building and network expansion.
The planning stage of new roads and other linear infrastructure needs to include more adequate assessments of effects on connectivity, especially in regions where road construction is rampant. This includes most of the tropical regions, that comprise most of the planet’s biodiversity. Although EIA is formally adopted in most of these countries, like Brazil (from where our experience comes), these steps need to be urgently followed to prevent or minimise connectivity losses caused by present and future road projects.
Author information:
Larissa Oliveira Gonçalves - Road and Railroad Ecology Center - Núcleo de Ecologia de Rodovias e Ferrovias (NERF/UFRGS), Federal University of Rio Grande do Sul, Brazil
Andreas Kindel - Road and Railroad Ecology Center - Núcleo de Ecologia de Rodovias e Ferrovias (NERF/UFRGS), Federal University of Rio Grande do Sul, Brazil and Ecology Graduate Program, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
Vinicius Augusto Galvão Bastazini - Rui Nabeiro Biodiversity Chair, University of Évora, Évora, Portugal and MED - Mediterranean Institute for Agriculture, Environment and Development, & CHANGE–Global Change and Sustainability Institute, Institute for Advanced Studies and Research, University of Évora, Portugal
Fernanda Zimmermann Teixeira - Road and Railroad Ecology Center - Núcleo de Ecologia de Rodovias e Ferrovias (NERF/UFRGS), Federal University of Rio Grande do Sul, Brazil and Ecology Graduate Program, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
Source:
Larissa Oliveira Gonçalves, Andreas Kindel, Vinicius Augusto Galvão Bastazini & Fernanda Zimmermann Teixeira (2022) Mainstreaming ecological connectivity in road environmental impact assessments: a long way to go, Impact Assessment and Project Appraisal, DOI: 10.1080/14615517.2022.2099727
Editor:
Jochen Jaeger
Cite this summary:
Larissa Oliveira Gonçalves, Andreas Kindel, Vinicius Augusto Galvão Bastazini & Fernanda Zimmermann Teixeira (2022). Steps to improve connectivity consideration in EIAs for road projects. Edited by Jaeger, J., TransportEcology.info, Accessed at: https://transportecology.info/research/connectivity-importance-in-EIAs[Date accessed].