Global Study Reveals Urbanization and Agriculture Threatening Bird Diversity, Ecosystem Resilience
November 26, 2025
Functional redundancy acts as ecological insurance; when redundancy declines, ecosystems become more vulnerable to shocks and biodiversity loss.
A global study across nearly 3,700 bird species at 1,200 sites finds that land-use changes, including urbanization and agricultural expansion, reduce bird functional diversity and weaken ecosystem stability and resilience.
Management implications stress protecting functionally distinct specialists in intact ecosystems, since their loss lowers ecological insurance against disturbances and reduces resilience.
The study highlights trait-based approaches for understanding biodiversity resilience and urges conservation planning to explicitly include functional diversity.
Spatial analyses show the strongest losses in functional diversity and redundancy in tropical and lower-latitude regions, where frugivores and insectivores are most vulnerable, threatening seed dispersal and pest control in disturbed habitats.
Functional vulnerability metrics combine disturbance sensitivity with each species’ redundancy, revealing declines in both trait-based and rarity-based vulnerability, especially in young secondary vegetation and agricultural landscapes.
Unexpectedly, greatest instability arises from reduced functional trait redundancy in moderately to heavily disturbed environments rather than in untouched primary forests.
Future work should explore how specific trait combinations affect functions under different disturbances and integrate socio-economic factors to guide sustainable land-use decisions.
(Note: No content provided in this point.)
Secondary forests and lightly disturbed habitats can retain functional redundancy similar to pristine forests, underscoring restoration and semi-natural vegetation as key to maintaining ecosystem functions.
Published in Nature, the research shows how agricultural expansion, urbanization, and intensification alter bird communities and diminish functional diversity, compromising pollination, seed dispersal, and pest control.
Weeks and colleagues sampled bird assemblages across forests, croplands, and cities worldwide to assess how land-use shifts affect avian functional diversity and ecological stability.
The Nature article, dated today, introduces a framework for assessing ecosystem fragility and offers tools to guide conservation policy by focusing on vital ecological roles rather than sheer species counts.
Computer-based extinction simulations show land-use change erodes this ecological buffer, increasing the risk of cascading effects like reduced forest regeneration, lower carbon storage, and higher pest pressures.
Sensitivity analyses indicate functional stability generally declines with increasing land-use intensity when considering climate-related traits, passive extinction, and alternative extinction metrics.
In disturbed landscapes, reduced redundancy lowers resilience to future shocks; simulations reveal a net decline in functional resistance and stability, especially in agricultural and urban areas.
Functional redundancy may briefly rise moving from pristine to disturbed primary vegetation but drops sharply in croplands and highly urbanized zones, signaling weakened resilience with intensified land use.
Although some disturbed assemblages appear less vulnerable due to prior filtering of sensitive species, simulated extinctions show that resilience declines as trait redundancy diminishes.
Land-use changes can erode not just species richness but also the distribution of functional traits, making ecosystems more vulnerable to further disturbances.
Conservation should protect functional trait space and redundancy, not merely species counts, to sustain services like pollination networks, nutrient cycling, and trophic interactions.
Overall, the study presents a holistic view of how land-use change threatens biodiversity and ecosystem stability, urging urgent conservation and restoration.
Key authors include Thomas Weeks and Joseph Tobias of Imperial College London, with collaboration from David Edwards of the University of Cambridge.
Anthropogenic land-use change is a major driver of biodiversity shifts, making it essential to study functional diversity and its stability.
Note: All points reflect the article’s emphasis on functional diversity, redundancy, and resilience in response to land-use change.
In pristine ecosystems, rare species with unique trait combinations create high functional vulnerability under human pressure, underscoring the importance of preserving natural refuges.
Birds with specific traits (body size, beak shape, diets) are more likely to disappear, weakening the insurance effect that helps ecosystems cope with losses.
Disturbed habitats are dominated by disturbance-tolerant species occupying similar niches, reducing functional diversity and key ecosystem services.
Specialists displaced by generalists in modified habitats lead to lower functional diversity and reduced trait redundancy, weakening resilience.
FD and redundancy declines are uneven across trophic guilds, with frugivores and invertivores showing steep losses, while some generalists may persist.
The study calls for urgent policy action to preserve functional diversity to sustain essential ecosystem services for human well-being and economic stability.
Carmona notes the piece references related studies and datasets, reinforcing its conclusions on ecology, trait-based approaches, and biodiversity stability.
Across landscapes, large-bodied and narrowly niche species are disproportionately lost in disturbed areas; mature secondary forests recover some FD, but urban disturbance leads to substantial FD declines.
The article advocates shifting conservation priorities toward preserving functional integrity and redundancy to bolster resilience amid ongoing land-use change.
Summary based on 4 sources
Get a daily email with more Science stories
Sources

Nature • Nov 26, 2025
Land-use change undermines the stability of avian functional diversity
Nature • Nov 26, 2025
Land-use changes threaten the safety net for birds
Phys.org • Nov 26, 2025
Global bird study reveals declining ecosystem resilience
BIOENGINEER.ORG • Nov 26, 2025
Land-Use Change Threatens Bird Diversity Stability