Patterns in Urban Soil Biodiversity:
Biotic Homogenization and Urban Vicariance
Katalin Szlávecz, Elisabeth Hornung
Csaba Csuzdi, Zoltán Korsós, Ferenc Vilisics,
Péter Sólymos, Richard Pouyat
Questions and Challenges
• Are there general patterns among cities?
– Different land use history, management, population
– Different sampling methodology
• What are the similarities and differences among soil invertebrate taxa?
– Different natural history
– Difficulties in zoogeographical evaluation
Landscape Heterogeneity
Baltimore, 1752
Remnant fragments
Parks
Lawns, gardens
Greenhouses
Buildings
Increasinghuman impact
The Losers: Species Rich Taxa
rs (urban) = 0.68 0.05<p<0.1
rs (suburban) = 0.86 0.025<p<0.05
0
20
40
60
80
100
0 100 200 300 400 500
Regional species pool
Fa
un
a r
em
ain
ing
(%
)
Urban green spaces
Suburban included
AraneaeCarabidae
Scarabaeidae
Elateridae
Diplopoda
Isopoda
Opiliones
Memorabilia Zoologia 34. 1981
Novel Habitats: Greenhouses
• Percentage of fauna:– Earthworms 7.8%– Isopods 7.3%– Diplopods 5%
• Origin: – SE Asia, Africa, Tropical America, Canary
Islands, Iberian region
Novel Habitats: Buildings
Csuzdi et al. 2008
Dichogaster bolaui
Greenhouses in the temperate regions
Buildings: sewer system Domicole species
Many habitats in the warmer regions
Biotic Homogenization
Method: biotic element analysis; model based clustering of species’ ranges
Earthworms
Isopo
da
Millipede
s
Cities 6 11 6
Species 25 46 62
Homogenizing sp. 8 14 10
% 32 > 30 > 16
Similarity of soil fauna
Similarity is decreasing with increasing geographical distance
Homogenizing sp.
All species
Native species
Betasim = pmin(b,c)/(pmin(b,c)+a)b and c : number of species in one or the other community onlya: number of species in both communities
Urban explorers: Urban Vicariance
Cylindroiulus punctatus, Atlantic
species
Cylindroiulus boleti, Continental species
North America:
Baltimore
Urban Vicariance: Examples
Brachyiulus bagnalli B. pusillus Continental Atlantic Budapest Warsaw, Coppenhagen
N Am: Baltimore
Polydesmus complanatus P. inconstans Continental AtlanticAtlantic
Budapest, Moscow Hamburg, Lublin, Warsaw
N Am: Baltimore
Summary
• All three groups have species adapted to novel habitats, but proportion and significance of exotics is taxon dependent
• Local fauna is still present, but with varying success
• Both relative and absolute density changes along the urban-rural gradient
• Earthworms showed the highest tendency for homogenization
Acknowledgements
National Science Foundation
USDA Forest Service
Hungarian Science Foundation (OTKA)
Hungarian Natural History Museum
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