Alternative pathways to a sustainable future lead to contrasting biodiversity responses

Inês S Martins,Laetitia M Navarro,Henrique M Pereira,Isabel M.D Rosa

doi:10.1016/j.gecco.2020.e01028

Abstract

Land-use change is currently the main driver of biodiversity loss. Projections of land-use change are often used to estimate potential impacts on biodiversity of future pathways of human development. However, such analyses frequently neglect that species can persist in human-modified habitats. Our aim was to estimate changes in biodiversity, considering affinities for multiple habitats, for three different land-use scenarios. Two scenarios focused on more sustainable trajectories of land-use change, based on either technological improvements (Pathway A) or societal changes (Pathway B), and the third reflected the historical or business-as-usual trends (Pathway 0). Using Portugal as a case study, we produced spatially-explicit projections of land-use change based on these pathways, and then we assessed the resulting changes in bird species richness and composition projected to occur by 2050 in each of the scenarios. By 2050, alpha and gamma diversity were projected to decrease, relative to 2010, in Pathway 0 and increase in Pathways A and B. However, different pathways favored different species groups, and presented strong regional differences. In the technological improvement pathway, loss of extensive agricultural areas led to an increase in both natural and extensive forest areas. In this pathway, forest species increase at the expense of farmland species, while in the societal change pathway the reverse occurs, as extensive agricultural areas were projected to increase. We show that while multiple positive pathways (A and B) for biodiversity can be envisioned, they will lead to differential impacts on biodiversity depending on the transformational changes in place and the regional socio-economic context. Our results suggest that considering compositional aspects of biodiversity can be critical in choosing the appropriate regional land-use policies.

Highlights

Species diversity has been declining steadily over the last century (Díaz et al, 2019)
By 2050, and in the business-as-usual scenario (Pathway 0), we projected an increase in the area of both intensive and extensive forest, in the central and north-northeast part of Portugal (Fig. 1b, Table 2)
In the southeast and northeast part of Portugal, such a decrease is projected to be a result of land abandonment and intensification of the agricultural areas, while in the center and northwest of the country agriculture areas are mostly converted to extensive forest areas

Summary

Introduction

Species diversity has been declining steadily over the last century (Díaz et al, 2019). The pressure on land is likely to increase, as global human population is expected to grow from around 7 billion in 2010 to 9 billion by 2050, increasing food consumption by 1.7 times and wood consumption by 1.3 times (van Vuuren et al, 2012). Such increase in consumption is likely to lead to further habitat conversion and associated biodiversity change. Exploratory scenarios tend to examine the consequences of a persistence of ‘business as usual’ trends (i.e., population growth, economic growth, land-use change trends), as opposed to alternative “radical” actions (i.e., change in consumption patterns or land-use practices)

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Conclusion