Download Biotic Homogenization

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
Remnant fragments
Parks
Baltimore,
1752
Lawns, gardens
Greenhouses
Increasing
human impact
Buildings
Baltimore Ecosystem Study
http://www.beslter.org/
The Losers: Species Rich Taxa
Urban green spaces
Fauna remaining (%)
100
Suburban included
80
Opiliones
60
Isopoda
Diplopoda
40
Araneae
Elateridae
20
Carabidae
Scarabaeidae
0
0
100
200
300
400
500
Regional species pool
rs (urban) = 0.68 0.05<p<0.1
Memorabilia Zoologia 34. 1981
rs (suburban) = 0.86 0.025<p<0.05
Species dominance changes in the city:
Sorø, Denmark
Porcellio scaber
Vilisics et al. 2007
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
Dichogaster bolaui
Buildings: sewer system
Domicole species
Greenhouses in the
temperate regions
Many habitats in the
warmer regions
Csuzdi et al. 2008
Biotic Homogenization
Earthworms
Isopoda
Millipedes
Cities
6
11
6
Species
25
46
62
Homogenizing sp.
8
14
10
30 >
16
%
32 >
Method: biotic element analysis; model based clustering of
species’ ranges
Similarity of soil fauna
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 only
a: number of species in both communities
Similarity is decreasing with increasing geographical distance
Urban explorers:
Urban Vicariance
North America:
Baltimore
Cylindroiulus punctatus,
Atlantic species
Cylindroiulus boleti,
Continental species
Urban Vicariance: Examples
Brachyiulus bagnalli
Continental
Budapest
B. pusillus
Atlantic
Warsaw, Coppenhagen
N Am: Baltimore
Polydesmus complanatus
Continental
Budapest, Moscow
P. inconstans
Atlantic
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