Trait-mediated responses of native plant diversity to combined urban and alien pressures in wastelands.
Yang J, Yin J, Lin X, He M, Zhang B
Urban Ecology
That overgrown lot down the street — full of weeds and cracked concrete — is quietly losing its native wildflowers not just to pavement, but to the nitrogen-saturated soil that invasive plants and urban runoff create together.
When city development and invasive plants both move into an abandoned or neglected piece of land, native plants don't just face one problem — they face two at once, and the combination is worse than either alone. Too much nitrogen in the soil, largely from urban pollution and invasive plant litter, acts like a lever that tips the balance against native species. The natives that survive shift their growth strategy toward fast, leafy, nutrient-grabbing growth — which sounds adaptive but actually makes them weaker and more vulnerable over time.
Key Findings
Native plant diversity was highest only when both urbanization levels and invasive plant diversity were simultaneously low — suggesting either pressure alone can undermine natives, but together the effect compounds.
Soil nitrogen emerged as the key mediating factor: elevated nitrogen driven by urban inputs and invasive species disrupted native plant communities more than any other soil variable measured.
Surviving native plants shifted toward 'acquisitive' leaf traits — longer leaves, higher leaf nitrogen, lower dry matter and carbon-to-nitrogen ratio — indicating a stress response that trades long-term resilience for short-term resource capture.
chevron_right Technical Summary
Urban wastelands where city sprawl meets invasive plants are a double blow for native wildflowers: together, urbanization and alien species drive native plant diversity down, with soil nitrogen overload as the key culprit pushing survivors toward fast-and-fragile growth strategies.
Abstract Preview
Urban wastelands, noval anthropogenic ecosystems, remain understudied using integrative frameworks linking community assembly to ecosystem management. Current research of these systems largely trea...
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