Data from: Predation risk shaped by habitat and landscape complexity in urban environments

1. Habitat loss and modification are hallmarks of anthropogenic
ecosystems, but the consequences for ecosystem functions and services
often remain unclear. Understanding these links in cities is complicated
by strong but fine-scale differences in habitat structure among green
space patches, and a high variance in habitat amount across urban
landscapes. 2. We used airborne laser scanning (ALS) data to disentangle
the effects of 3D woody habitat heterogeneity of urban home gardens, and
woody habitat amount at four landscape spatial scales (50, 100, 250, 500
m), on the predation risk of artificial sentinel prey by birds and
arthropods. 3. In both predator groups, and at all the investigated
spatial scales, cross-scale interactive effects between garden habitat
heterogeneity and habitat amount in the urban landscape were the main
drivers of predation. Risk of bird predation by birds was highest in
heterogeneous garden habitats, but only in densely built urban landscapes
where habitat amount was low to intermediate (10-20%) at large spatial
scales (250-500 m). It dropped independently of garden habitat
heterogeneity when habitat amount became too low (<10%) at small
(50-100 m) spatial scales. In contrast, risk of predation by arthropods
mostly peaked in homogenous garden habitats when habitat amount was
intermediate (20%) at large spatial scales. 4. Our findings show that the
ability of urban green space patches to sustain ecosystem functions in
cities mainly depends on cross-scale interactive effects with larger-scale
habitat amount. In birds, predation risk can increase when high
patch-scale habitat heterogeneity contrasts with reduced larger-scale
habitat amount, suggesting concentration effects. Yet thresholds exist
under which ecosystem functioning drops independently of habitat
structure. 5. Synthesis and applications. The potential of small-scale
interventions to enhance habitat heterogeneity (e.g. by planting native
trees with understory shrubs) for restoring ecosystem functions such as
bird predation in urban areas is dependent on wider landscape habitat
structure. Urban planning should therefore adopt a multi-scale approach to
sustain and restore ecosystem functions and services; a simple but still
not broadly recognized finding. Airborne laser scanning is a useful tool
to infer habitat structure across a hierarchy of scales in spatially
heterogeneous anthropogenic ecosystems.