Looking beneath apparent abundance
The team collected 245 Oxyopes sertatus from 17 sites along an urban-rural gradient in central Taiwan. They measured land use at local and landscape scales, then compared mitochondrial DNA with genome-wide single-nucleotide polymorphisms generated by RAD sequencing.
Genome-wide diversity declined as urbanization increased. Urban populations were also more genetically differentiated from one another than rural populations, consistent with roads and built areas reducing movement and gene flow.
A barrier, not complete isolation
Population-structure analyses did not separate the spiders into fully distinct genetic clusters, so dispersal has not stopped entirely. The result is therefore not “city spiders are a different species,” but evidence of rapid erosion and redistribution of genetic variation across a fragmented landscape.
Why green connections matter
The authors argue that urban planning should maintain habitat connectivity. For invertebrates, connected vegetation can matter even when a familiar species still appears common in individual parks or gardens.