Impact of urban developments on the functional connectivity of forested habitats: a joint contribution of advanced urban models and landscape graphs

Abstract

International audienceThe impacts of urban growth on biodiversity vary according to the form and the intensity of urbanisation.However, there is a lack of knowledge about the consequences of the type of urban structure (e.g. mono-centric vs polycentric), the shape of urban boundaries, the local density of residential development, on the habitats of wildlife species. In this context, this paper focuses on the relationship between forms ofurbanisation and functional connectivity of ecological habitats. In the urban region of Besanc¸ on (easternFrance), three emblematic protected species were selected to represent forest mammals. From the initialstate describing current land cover, five prospective residential development scenarios were simulated,corresponding to the form currently most commonly found (e.g. compact development, transit-orienteddevelopment, polycentric development). For each scenario, we also simulate the volume of traffic on theroad network to allow for the barrier effect of roads on habitat connectivity. Then, for each developmentscenario, we model the functional connectivity of habitats of the various target species using landscapegraphs. Results show that compact city maintains more functional connectivity for all the species con-sidered whereas urban sprawl leads to much more marked impacts. Moderately compact and regulatedperiurban scenarios have intermediate levels of impact. The transit-oriented development scenario pro-duces specific impact values according to the species. An interesting point is that the decline in functionalconnectivity of forest habitats is more due to increased traffic than residential development proper. Thisoutlines the relevance of integrated models for simulating both land use and transport at a fine scale

Metapopulation modelling of long-term urban habitat-loss scenarios

“…Our workflow can, however, be applied to any level of complexity in scenario or model design. For example, the IFM could be adapted to incorporate the increased complexity in functional connectivity found in urban landscapes (Tannier et al 2016) instead of Euclidean distance between patches (e.g. Watts and Handley 2010).…”

Modelling in the Context of an Environmental Mobilisation: A Graph-Based Approach for Assessing the Landscape Ecological Impacts of a Highway Project

“…However, this kind of fragmentation (sprawl) can be partially mitigated by the possibility of species movement in the interstitial zones of the urban development. The barrier effect depends on the shape and intensity of urbanisation (Alberti, 2005) and is generally intensified in the case of compact and dense cities (Tannier et al, 2016). In terms of transport infrastructure, fragmentation occurs by disconnection and reinforces the barrier effect, often over several tens of kilometres (Forman, Alexander, 1998;Fu et al, 2010;Girardet et al, 2013).…”

“…Some studies have focused on a retrospective approach by assessing connectivity losses caused by the construction of major transport infrastructures (e.g., Fu et al, 2010;Clauzel et al, 2013;Girardet et al, 2013). Other studies have used a prospective approach by assessing the potential impact of different land-use planning scenarios, such as the construction of a new highway (Vasas et al, 2009) or new residential development areas (Tannier et al, 2012(Tannier et al, , 2016. These studies have focused on the overall impact of a development or major transport infrastructure on a regional scale (calculation of a global connectivity metric) or habitat patches (calculation of a local metric).…”

Environmental impact assessment of development projects improved by merging species distribution and habitat connectivity modelling

“…Studies combining SDM and spatial graphs showed the relevance of both modelling approaches (Duflot et al, 2018;Rödder et al, 2016), but further research is required to better incorporate them into environmental assessment of development projects and to guide decision-making. In addition, these approaches have been mostly applied to large urban project (Tannier et al, 2016) or to major transportation infrastructure projects (Clauzel et al, 2013;Mimet et al, 2016), but not to smaller development projects also subject to EIA (like residential neighborhoods, industrial and commercial areas, sports and leisure facilities, housing developments, etc.). However, these smaller projects and their multiplication severely impact the habitats of some suburban species, hence decreasing their moves and populations (Ayram et al, 2017).…”