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.

土地利用变化目前是生物多样性丧失的主要驱动力。土地用途变化的预测经常被用来估计人类发展未来途径对生物多样性的潜在影响。但是，此类分析经常忽略了物种可以在人类改造过的栖息地中持续存在的情况。我们的目标是在三种不同的土地利用情景下，考虑多个生境的亲和力，估算生物多样性的变化。基于技术改进（途径A）或社会变化（途径B），两种情况着眼于更可持续的土地利用变化轨迹，第三种情况反映了历史趋势或照常发展趋势（途径0）。以葡萄牙为例，我们根据这些途径得出了土地利用变化的空间明晰预测，然后我们评估了每种情况下预计到2050年禽类物种丰富度和组成发生的变化。到2050年，相对于2010年，途径0的alpha和γ多样性预计会减少，而途径A和B的alpha和γ多样性则会增加。但是，不同的途径有利于不同的物种组，并表现出强烈的区域差异。在技​​术改进途径中，大面积农业面积的减少导致自然和大面积森林面积的增加。在这一途径中，森林物种的增加以农田物种为代价，而在社会变革途径中，情况则相反，因为预计广泛的农业面积将增加。我们表明，虽然可以设想到生物多样性的多种积极途径（A和B），它们将导致对生物多样性的不同影响，这取决于当地的转型变化和区域社会经济背景。我们的结果表明，在选择适当的区域土地使用政策时，考虑生物多样性的组成部分可能至关重要。