Land Cover Limits Birds’ Escape Routes in Iberia
New modelling study shows that northern Iberian bird species face dramatic habitat losses under climate change, with land cover playing a crucial role in constraining their ability to shift ranges
Climate change and habitat in tandem
A new study published in Ecology and Evolution by Laura Cardador and colleagues highlights that climate change cannot be considered in isolation when forecasting the future of Iberia’s birds. Analysing 32 northern species at the southern edge of their European ranges, the researchers found that while rising temperatures are a dominant driver of range contractions, land cover strongly modifies the extent to which species can respond.
Using ecological niche models, the team compared scenarios where climate, land cover, or both were allowed to change. When only climate was altered, predicted range shifts were larger, but when land cover changes were included, the scope for movement contracted sharply. This demonstrates that habitat availability - from forests to grasslands and croplands - constrains whether species can track shifting climate envelopes.
Severe habitat losses for mountain specialists
The findings are starkest for high-altitude specialists. Species such as the Tengmalm's Owl, Eurasian Treecreeper, Ptarmigan, White-winged Snowfinch, Alpine Accentor and Ring Ouzel are projected to lose between 79 and 85 per cent of suitable habitat in northern Iberia by 2055 under combined climate and land cover scenarios. Already existing in small, fragmented populations, these birds face heightened extinction risk in the region.
Even under the more optimistic emissions pathway, reductions remain dramatic, underscoring that limiting warming alone will not prevent biodiversity loss if habitats are degraded or fail to expand into newly suitable areas.
North-east shifts versus habitat traps
Overall, most species are predicted to shift their potential ranges north-eastwards as climates warm and precipitation declines. Yet when land cover constraints were factored in, some species showed little capacity to move, and in some cases, range shifts even trended southwards. This mismatch reveals how landscapes can act as traps, preventing birds from reaching newly suitable climates.
Temperature, particularly maximum summer heat, emerged as the single most important factor shaping current distributions, while land cover modulated whether species could persist or relocate.
Conservation implications
The study reinforces the importance of coupling climate adaptation with land management. “Our results highlight the need to incorporate land cover alongside climate adaptation strategies in conservation planning,” the authors write. While climate trajectories are global, land use is subject to regional planning, offering opportunities for proactive interventions.
Conserving open alpine habitats, restoring forests, and avoiding land-use changes that fragment natural areas could help buffer species against climate stress. Even under the best-case scenario, declines are expected - but targeted management could soften the blow.
A warning beyond Iberia
Although focused on northern Iberia, the findings carry broader weight for conservation science. Climate-driven range shifts, long assumed to be the dominant story, may be severely curtailed by habitat realities. For birds perched at the edge of their ranges, climate change and land use together determine survival prospects - reminding us that conservation requires action on both global and local scales.
September 2025
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