In dense cities, bird richness tracked habitat area and connectivity more than urban form type
WHAT THE EVIDENCE SAYS
Researchers monitored birds across 30 Gothenburg sites in spring 2024: 19 sites representing three dense/compact urban form types and 11 greener reference areas. They recorded 61 species. Median species richness was lower in the dense/compact group than in reference areas (24 versus 33 species; p<0.001), but richness and composition did not differ significantly among the three urban form types themselves. Within the dense/compact sites, larger local natural-habitat area and greater structural connectivity were positively associated with species richness; in the best-supported model, a one-standard-deviation increase in local habitat area corresponded to about 16% higher expected richness and connectivity to about 10% higher richness.
WHY IT MATTERS / OUR READ
The planning signal is not that density is ecologically neutral. Dense and compact sites still underperformed greener reference areas. But within dense urban fabric, the broad form category was less informative than the amount of usable habitat retained locally and its connection to surrounding habitat. That shifts the design question from 'dense or compact?' toward how much habitat survives inside the fabric and whether it remains part of a functioning network.
CAVEATS / UNCERTAINTY
This is a 30-site observational study from one city and one spring season, focused on birds. Structural connectivity is a landscape proxy rather than measured movement, and the strongest 1.8-km scale is likely specific to Gothenburg's landscape. Passive acoustic/occurrence methods can miss infrequently vocalizing species. The associations should not be treated as universal design thresholds or proof that denser development causes the reported differences.
SOURCE
npj Urban Sustainability
View original evidence ↗
Across 30 Gothenburg sites, dense and compact neighborhoods had fewer bird species than greener reference areas, but the three urban form types did not differ significantly from one another; local natural habitat area and connectivity were the stronger within-city signals.
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