Biodiversity and Conservation 29: 2343–2359 (2020) DOI:10.1007/s10531-020-01977-9

Environmental determinants of diving assemblages in an urban landscape

廖文翡 史蒂芬·文 雅礼·尼耶梅莱 Wenfei Liao, Stephen Venn, Jari Niemelä Urban Ecology Research Group EcoEnv Science Day 18th Sept 2020 Helsinki As urban landscapes are highly fragmented, dispersal capacity will affect the distributions of different invertebrates …

Passive dispersers Active dispersers As urban landscapes are highly fragmented, dispersal capacity will affect the distributions of different taxa …

Passive dispersers Active dispersers

The diving beetle is suggested as an indicator taxon of aquatic invertebrate diversity (Bilton et al 2006) Only two papers about urban diving published almost 20 years ago  Diving beetles () are predaceous …

To sample diving beetles, we set activity traps in pond marginsand operated in water for 48h (Elmberg et al 1992)

Activity traps We found 39 species in 25 ponds at 10 sites during summer 2018, which is over 40% of dytiscid species in Uusimaa Region External feature Open land use data (HSY 2016)

• Percentage of impermeable surfaces Habitat features Internal features • Water depth to estimate margin steepness

• The presence or absence of fish Species Richness & Abundance

Site 1 Site 10 Site 2

Pond 7 Pond 1 Pond 1 Pond 1 Pond 2 Pond 2

Trap 5 Trap 1 Trap 8 Trap 7 Trap 10 Trap 2 Trap 6 Trap 15 So we fitted 2-way nested generalised linear mixed models (GLMM)…

Random effects: • Sites • Ponds Fixed effects: • Percentage of impermeable surfaces External feature • Margin steepness Internal features • Presence or absence of fish How does habitat fragmentation affect diving beetle diversity? Habitat fragmentation has negative effects on dytiscid species richness but NOT on their abundance….

Liao, Venn, Niemelä (2020) DOI:10.1007/s10531-020-01977-9 Active dispersers have their limitations in dispersal capacity

Most species couldn’t cope with 36% impermeable surfaces

Liao, Venn, Niemelä (2020) DOI:10.1007/s10531-020-01977-9 Active dispersers have their limitations in dispersal capacity

Most species couldn’t cope with 36% impermeable surfaces

Liao, Venn, Niemelä (2020) DOI:10.1007/s10531-020-01977-9 What features are important to make ponds as good habitats? Diving beetles prefer pond margins with gentle slopes… • Shelters from predators (Juliano 1991) • Habitats for pupation (Dolmen & Solem 2002)

Liao, Venn, Niemelä (2020) DOI:10.1007/s10531-020-01977-9 Ponds with fish had fewer species and individuals than ponds without fish Diving beetles prefer pond margins with gentle slopes… • Shelters from predators (Juliano 1991) • Habitats for pupation (Dolmen & Solem 2002)

Liao, Venn, Niemelä (2020) DOI:10.1007/s10531-020-01977-9 The presence of predatory fish not only decreases diving beetle diversity but also affects their species composition

Medium to large-sized species are more tolerant to fish than small species 

Liao, Venn, Niemelä (2020) DOI:10.1007/s10531-020-01977-9 Take-home messages

Urban wetlands can support a diversity of diving beetles

To support invertebrates in urban wetlands: • Make some wetlands free from predatory fish • Design some gentle sloping margins

Liao, W., Venn, S., & Niemelä, J. (2020). Environmental determinants of diving beetle assemblages (Coleoptera: Dytiscidae) in an urban landscape. Biodiversity and Conservation 29: 2343–2359 DOI:10.1007/s10531-020-01977-9 Thank you!

@wenfeiliao @wenfeiliao References

• Bilton, D. T., Mcabendroth, L., Bedford, A. L. A. N., & Ramsay, P. M. (2006). How wide to cast the net? Cross‐taxon congruence of species richness, community similarity and indicator taxa in ponds. Freshwater Biology, 51(3), 578-590. • Dolmen, D., & Solem, J. O. (2002). Life history of Ilybius fenestratus (Fabricius)(Coleoptera, Dytiscidae) in a central Norwegian lake. Aquatic , 24(3), 199-205. • Elmberg, J., Nummi, P., Pöysä, H., & Sjöberg, K. (1992). Do intruding predators and trap position affect the reliability of catches in activity traps?. Hydrobiologia, 239(3), 187-193. • Juliano, S. A. (1991). Changes in structure and composition of an assemblage of Hydroporus species (Coleoptera: Dytiscidae) along a pH gradient. Freshwater Biology, 25(2), 367-378. • Liao, W., Venn, S., & Niemelä, J. (2020). Environmental determinants of diving beetle assemblages (Coleoptera: Dytiscidae) in an urban landscape. Biodiversity and Conservation 29: 2343–2359 http://doi.org/10.1007/s10531-020-01977-9 Image Sources

• Asellus: https://www.flickr.com/photos/micks-wildlife-macros/3373465689 • Copepoda: https://lv.m.wikipedia.org/wiki/Att%C4%93ls:Copepodkils.jpg • Crussian carps: https://commons.wikimedia.org/wiki/File:CarassiusCarassius8.JPG • Dragonfly larvae: https://www.flickr.com/photos/davemedia/5886193050/in/photostream/ • Eurasian water shrew: https://www.flickr.com/photos/drinkermoth/8904617564 • Mayfly: https://www.pexels.com/photo/fly-insect-mayfly-1131422/ • Mosquito larvae: https://en.wikipedia.org/wiki/File:Culex_sp_larvae.png

• Skylines: https://www.facebook.com/veryFinnishproblems/photos/a.670924783048112/1661511980656049/?type=3&theater • Water Mite: https://commons.wikimedia.org/wiki/File:Водяной_клещ.jpg Image Sources

• Acilius canaliculatus: https://twitter.com/KarjalainenSami/status/673199542746116097/photo/1 • sturmii: http://www.eakringbirds.com/eakringbirds4/insectinfocusagabussturmii.htm • Dytiscus marginalis: https://www.naturepl.com/stock-photo-great-diving-beetle-dytiscus-marginalis- and-dragonfly-nymph-aeshnidae-nature-image01648586.html • Hydroporus pubescens: http://www.eakringbirds.com/eakringbirds4/insectinfocushydroporuspubescens.htm • Hydroporus striola: http://www.biopix.com/hydroporus-striola_photo-85542.aspx • Hyphydrus ovatus: http://www.eakringbirds.com/eakringbirds4/insectinfocushyphydrusovatus.htm

Other photos were taken by Wenfei Liao 