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

http://www.beslter.org/

Baltimore Ecosystem Study

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

Species dominance changes in the city:

Sorø, Denmark

Vilisics et al. 2007

Porcellio scaber

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