Talk given at IALE UK meeting, 1-3 September 2014. I discuss how to define an urban pond (more difficult than you'd think) and some preliminary data characterising urban pond ecology across multiple published and unpublished studies.

1. A comparative analysis of biodiversity in
urban ponds in the UK
Christopher Hassall1, David Gledhill2, Paul Wood3, Jeremy Biggs4
1Univ Leeds, 2Univ Salford, 3Univ Loughborough, 4Freshwater Habitats Trust
@katatrepsis
c.hassall@leeds.ac.uk

2. Acknowledgements
Institutional support Funders
Field assistants
Andrew Noble
Nicole Barber
Denny Moyers
Surveyors
Jonathan Guest
David Bentley

3. What is an “urban pond”?
urban pond

4. What is an “urban pond”?
© Crown Copyright 2014. An Ordnance Survey/EDINA supplied service.

5. What is an “urban pond”?
© Crown Copyright 2014. An Ordnance Survey/EDINA supplied service.

6. What is an “urban pond”?
© Crown Copyright 2014. An Ordnance Survey/EDINA supplied service.
Run-off
from dense
residential
Low connectivity
to other water
bodies
Industrial
run-off
Concrete edge,
poor vegetation
© 2014 Google

7. What is an “urban pond”?
Different design
Different context
Different management
Different priorities
JR P, CC-BY-NC 2.0, http://bit.ly/1rzf3RX; Nick M, CC-BY 2.0, http://bit.ly/VQmQM9; Reinhold Behringer,
CC-BY-NC-SA 2.0, http://bit.ly/1ATkvjn; Loz Pycock, CC-BY-SA 2.0, http://bit.ly/1wB04Jj
Hassall C (2014) The ecology and biodiversity of urban ponds. WIREs Water, 1, 187-206.

8. Management of urban ponds
2
5
3
2
1
3
2
2
1
2
1
1
1
1
Hassall C (2014) The ecology and biodiversity of urban ponds. WIREs Water, 1, 187-206.

9. A comparative analysis of urban ponds
Dataset N ponds
Moyers & Hassall (unpub) 11
Noble & Hassall (in review) 21
Barber & Hassall (unpub) 10
Hassall et al. (2011) 425
Wood et al. (2000) 36
Gledhill et al. (2008) 37
FHT (NPS) 153
FHT (TP) 76
FHT (ROPA) 179
TOTAL 938
186 urban ponds
751 non-urban ponds
Noble A, Hassall C (in review) Urban Ecosystems; Hassall C, Hollinshead J, Hull A (2011) Biodiversity and Conservation, 20, 3189-3222; Wood PJ, Barker S (2000) Applied
Geography, 20, 65-81; Gledhill DG, James P, Davies DH (2008) Landscape Ecology, 23, 1219-1230; Williams PJ, Biggs J, Barr CJ et al. (1998) Lowland Pond Survey, London,
DETR.

10. “Urban” vs “non-urban” ponds
Three main hypotheses:
1. Urban ponds exhibit biotic homogenisation
PREDICTION: urban communities are more
similar than rural communities
2. Urban landscapes are less permeable
PREDICTION: urban communities show stronger
spatial structuring than rural communities
3. Urban stressors reduce diversity
PREDICTION: urban ponds contain lower family
richness and diversity than rural ponds

11. Hypothesis 1: Biotic homogenisation
Urban
Compare samples of
Mahalanobis distances
between urban and non-urban
Non-urban

12. Hypothesis 1: Biotic homogenisation
Environment
W = 16514, p= 0.312
(Northing, altitude,
shade, pH, emergent
plants, area)
Biological community
W = 50282, p= 0.008

13. Hypothesis 1: Biotic homogenisation

14. Hypothesis 2: Landscape permeability
Urban
Non-urban
Distance between sites
Correlation between communities
Expect high autocorrelation at small
spatial scales in urban sites due to
low permeability, with negligible
correlation beyond that due to biotic
homogenisation
Expect low-moderate autocorrelation
across spatial scales with non-urban
ponds

15. Hypothesis 2: Landscape permeability
Urban ponds show greater fine-scale spatial autocorrelation, with
negative autocorrelation at intermediate (inter-city?) distances

16. Hypothesis 3: Urban biodiversity
Prevalence in non-urban Prevalence in urban
Taxon 1
Taxon 2
Taxon 3
Taxon 4
Taxon 5
Taxon 6
Taxon 7
Taxon 8
Taxon 9
Taxon10
Taxon 11
Taxon 12
Taxon 13
Taxon 14
Taxon 15
Taxon 16
Rapid drop-off in prevalence
as stress-tolerant species are
passed
Stress-tolerant species are
present, along with other
species with lower tolerance
to disturbance

17. Hypothesis 3: Urban biodiversity
1-1 0-0..88 0-0..66 0-0..44 0-0..22 00 0 0 0.2 0.2 0.4 0.4 0.6 0.6 0.8 0.8 1
1
Dytiscidae
Corixidae
Asellidae
Limnephilidae
Coenagrionidae
Gerridae
Haliplidae
Aeshnidae
Erpobdellidae
Sphaeriidae
Gammaridae
Physidae
Hydrometridae
Hydraenidae
Pisidiidae
Noteridae
Gyrinidae
Polycentropodidae
Naucoridae
Crambidae
Dugesidae
Nemouridae
Tipulidae
Acroloxidae
Pyralidae
Pleidae
Hirudidae
Ostracoda
Dryopidae
Culicidae
Psychodidae
Limacidae
Helodidae
Dixidae
Cladocera
Viviparidae
Stratiomyidae
Simuliidae
Paguroidea
Leuctridae
Hydroptilidae
Glossosomatiidae
Ephemeridae
Ceratopogonidae
Astacidae
Ancylidae
Tortricoidea
Sericostomatidae
Potamanthidae
Perlodidae
Niphargidae
Limnichidae
Heteroceridae
Hebridae
Gastrodontidae
Ephemerellidae
Dreissenidae
Calopterygidae
Bibionidae
Argulidae
Anthribidae
W = 10835, p = 0.886
103 taxa 91 taxa

18. Summary of hypotheses
Three main hypotheses:
1. Urban ponds exhibit biotic homogenisation
PREDICTION: urban communities are more
similar than rural communities
2. Urban landscapes are less permeable
PREDICTION: urban communities show stronger
spatial structuring than rural communities
3. Urban stressors reduce diversity
PREDICTION: urban ponds contain lower family
richness and diversity than rural ponds




19. Implications for management
Regardless of function, urban ponds
promote aquatic biodiversity
The diversity of urban pond types
may be key to this role, so diversity
of types must also be conserved
Biodiversity may persist despite
conflicting management priorities
Easy-wins could further enhance
this resource (revegetation,
strategic pond creation, pollution
reduction)

20. Take Home Messages
1. To find out what an urban site is, compare
with non urban
2. Synthetic approaches provide additional
insights (meta-analyses often not possible)
3. Ecological theories about urban environments
may not hold for ponds
4. Urban ponds may have a high biodiversity
value which justifies protection, but might not
need it!

22. A comparative analysis of urban ponds
© Crown Copyright 2014. An Ordnance Survey/EDINA supplied service.

23. Three measures of “urbanness”
In/out Distance to edge 1km buffer