We (me, Vinicius and Fernando Ascensão) have just recently pusblished a new preprint (currently submitted elsewhere) which makes me really proud! In this paper, entitled “Wildlife-vehicle collisions simplify regional food webs” we demonstrate that, for example, in areas surrounding major cities there might be a drastic loss of trophic interactions (about 90%).
A total of 186 species faced significant risks of local extinction due to direct roadkill effects, while 190 species had trophic interaction losses due to indirect effects, such as the loss of their prey species.
Apex predators exhibited lower direct roadkill impacts while basal-level species are more exposed to direct effects, potentially triggering a cascade of interaction disruptions. This is probably because top-level species were already affected by the effects of roads, and that effect is already present in the occurrence data.
Our findings underscore the necessity for tailored conservation measures to reduce roadkill risk, targeting different trophic levels, to preserve ecological network integrity amidst road development programs.
* This post has been written by Vinicius Bastazini, Larissa Oliveira Gonçalves,Andreas Kindel andFernanda Zimmermann Teixeira
A once borderless world occupied by vast extensions of natural habitats of all sorts and shapes has become shredded into pieces with the increase of human activities in the past centuries, especially after the Industrial Revolution (United Nations Environment Programme 2019). Habitat fragmentation, a process in which contiguous habitats are divided into smaller and somewhat isolated patches, has become a ubiquitous result of human activities, threatening species both on land and in the oceans. Dampening the effects of habitat fragmentation on biodiversity has become a conservation priority across the globe, with much effort put forward in order to maintain or restore the connectivity of habitat patches scattered on human-dominated landscapes.
Ecological connectivity can be broadly defined as the degree of connection among patches of habitats distributed in a landscape, facilitating the movement of species and the provision of ecological functions and services on which we depend upon (we have published a series of posts in our blog with analytical tools and issues related to ecological connectivity, see them here and here). Changes in ecological connectivity have profound effects on population abundance and persistence. These effects can scale up across levels of biological organization, altering patterns of species composition, richness and interspecific interactions, ultimately affecting ecosystem functioning. Thus, due to its paramount importance in safeguarding biodiversity in the present and in the near future, ecological connectivity is considered an essential component of climate change adaptation (Torres et al. 2022).
Despite its importance, changes in ecological connectivity are usually ignored in Environmental Impact Assessments (EIAs). EIAs are one of the most important instruments used worldwide to avoid or reduce the impacts of anthropogenic developments on biodiversity at the national or regional levels. They include the process of identifying, predicting, evaluating and mitigating impacts prior to the implementation of development proposals and, as such, they are the best opportunity to avoid the loss of ecological connectivity.
In a recent paper led by Larissa O. Gonçalves, we show ways of overcoming the existing gaps and obstacles in the assessment of ecological connectivity loss in EIAs of transport infrastructure projects, namely roads and railways. We also identify directions for future research programs that can contribute to integrating ecological connectivity into EIA practice and suggest how to improve mitigation design and implementation. Our paper is part of a special issue featuring seven articles, which resulted from a session titled ‘Prioritizing landscape connectivity in environmental impact assessment’ that took place in the 2021 International Conference of the International Association for Impact Assessment.
We also suggest 14 basic steps, summarized in Figure 1, that would improve connectivity assessments in EIAs and contribute to better mitigation planning for the negative effects of human developments on biodiversity and ecological functions (for a detailed description of these steps, please refer to the original paper, or see a summary here).
Figure 1: Steps to improve connectivity analyses and assessment in Environmental Impact Assessment for road projects. Although each step can be applied independently from one another, they should be progressively included into the EIA practice.
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