Landscape configuration and habitat complexity shape arthropod assemblage in urban parks

Abstract

The urbanization process systematically leads to the loss of biodiversity. Only certain arthropods are resilient to the urbanization process and can thrive in the novel conditions of urbanized landscapes. However, the degree to which arthropod communities survive in urban habitats depends on landscape and local effects and biological interactions (e.g., trophic interactions). In the present study, we examined the relative importance of various factors at landscape (isolation, edge density and area of surrounding greenery) and local (size of park, canopy cover, understory vegetation cover, defoliation depth, weight of dried leaves, soil temperature, soil moisture, and soil pH) spatial scales on the diversity of ants, beetles and spiders in urban parks. Our results indicated that park edge density was negatively correlated with diversity metrics in ants, beetles, and spiders in urban parks relative to the degree of proximity with the peri-urban forest. In other words, parks that located adjacent to the peri-urban forest may not necessarily have high biodiversity. The results suggested that man-made structures have been effective dispersal barriers that limit the spillover effects of ants and spiders but not the spillover of comparatively strong fliers, such as beetles. However, the area of surrounding greenery may have facilitated the colonization of forest-dependent taxa in distant parks. Large parks with reduced edge density supported a higher arthropod diversity because of the minimal edge effect and increased habitat heterogeneity. Vegetation structure consistently explained the variability of ants, beetles, and spiders, indicating that understory plant litter is crucial for providing shelters and hibernation, oviposition, and foraging sites for the major taxa in urban parks. Therefore, efforts should focus on the local management of ground features to maximize the conservation of biological control in urban landscapes.

Figure 1

Redundancy analysis (RDA) biplot (a) showing the distribution of ant community composition (solid arrows) in relation to in-situ environmental variables (empty arrows). Canonical correlation analysis (CCA) biplot (b,c) showing the relationship between beetle and spider community (empty triangles) and in-situ environmental variables (empty arrows) in survey parks. Ant genera: Te, Tetramorium; Mo, Monomorium; Phe, Pheidologeton; Pa, Paratrechina; Ph, Pheidole; Ta, Tapinoma; Pac, Pachycondyla; Tec, Technomyrmex; So, Solenopsis; Cr, Crematogaster; Pl, Plagiolepis; Ca, Cardiocondyla; Ano, Anoplolepis; Oc, Ochetellus; Ce, Cerapachys; Cam, Camponotus; Po, Polyrhachis; Ny, Nylanderia; Fo, Formica; St, Strumigenys; An, Anochetus; Re, Recurvidris. Beetle families: Car carabidae; Anb anobiidae; Ly lymexylidae; Si silvanidae; Cu curculionidae; Cer ceratocanthidae; El elateridae; Cup cupedidae; Ch chrysomelidae; Sc scarabaeidae; Hy hybosoridae; Ant anthicidae; Di diphyllostomatidae; Mon monotomidae. Spider families: Sa salticidae; At atypidae; Pi pisauridae; Lyc lycosidae; Ox oxyopidae; Oo oonnopidae; Any anyphaenidae; Gn gnaphosidae; Phi philodromidae; Th thomisidae; Zo zodariidae. In-situ environmental variables: Size size of park; CanpCovr canopy cover; UndVegCv understory vegetation cover; DeflDept defoliation depth; WeigOfDr weight of dried leaves; SoilTemp soil temperature; SoilMois soil moisture; SoilPH soil pH.

Figure 2

The similarity of community composition of ants (a,d), beetles (b,e), and spiders (c,f) in four park size groups (XS, extra small; S, small; M, medium; L, large) and seven isolation categories (I, < 1.0 km; II, 1.0–1.9 km; III, 2.0–2.9 km; IV, 3.0–3.9 km; V, 4.0–4.9 km; VI, 5.0–5.9 km; VII, > 6.0 km). Dendrograms of group-averaged clustering of test taxa are based on means of Bray–Curtis distance. Solid lines represent significant difference among groups based on SIMPROF (p < 0.05). Color scale represent mean abundance in each size of park. Abbreviations for ant genera: Te, Tetramorium; Mo, Monomorium; Phe, Pheidologeton; Pa, Paratrechina; Ph, Pheidole; Ta, Tapinoma; Pac, Pachycondyla; Tec, Technomyrmex; So, Solenopsis; Cr, Crematogaster; Pl, Plagiolepis; Ca, Cardiocondyla; Ano, Anoplolepis; Oc, Ochetellus; Ce, Cerapachys; Cam, Camponotus; Po, Polyrhachis; Ny, Nylanderia; Fo, Formica; St, Strumigenys; An, Anochetus; Re, Recurvidris; The beetle families are: Car carabidae; Anb anobiidae; Ly lymexylidae; Si silvanidae; Cu curculionidae; Cer ceratocanthidae; El elateridae; Cup cupedidae; Ch chrysomelidae; Sc scarabaeidae; Hy hybosoridae; Ant anthicidae; Di diphyllostomatidae; Mon monotomidae; The spider families are: Sa salticidae; At atypidae; Pi pisauridae; Lyc lycosidae; Ox oxyopidae; Oo oonnopidae; Any anyphaenidae; Gn gnaphosidae; Phi philodromidae; Th thomisidae; Zo zodariidae.