Connectivity of stormwater ponds impacts Odonata abundance and species richness

I C Richmond; M C Perron; S P Boyle; F R Pick

doi:10.1007/s10980-024-01817-z

Connectivity of stormwater ponds impacts Odonata abundance and species richness

Landsc Ecol. 2024;39(3):63. doi: 10.1007/s10980-024-01817-z. Epub 2024 Feb 28.

Authors

I C Richmond^{1

2}, M C Perron^{1

3}, S P Boyle⁴, F R Pick¹

Affiliations

¹ Department of Biology, University of Ottawa, 30 Marie Curie Private, Ottawa, ON K1N 6N5 Canada.
² Department of Biology, Concordia University, 7141 Sherbrooke St. W., Montreal, QC H4B 1R6 Canada.
³ St. Lawrence River Institute of Environmental Sciences, 2 St. Lawrence Drive, Cornwall, ON K6H 4Z1 Canada.
⁴ School of Science and the Environment, Memorial University of Newfoundland - Grenfell, 20 University Dr, Corner Brook, NL A2H 5G5 Canada.

Abstract

Context: The successful dispersal of an animal depends, partly, on landscape connectivity. Urbanization poses risks to dispersal activities by increasing hostile land cover types.

Objectives: We investigated how connectivity of urban ponds impacted Odonata communities (dragonflies and damselflies), an order of semi-aquatic insects that actively disperse.

Methods: We sampled 41 constructed stormwater ponds and 8 natural ponds in a metropolitan area. The effect of connectivity and the quantity of available adjacent habitats was tested at different scales for dragonflies (900 m) and damselflies (300 m), determined by a literature analysis, to account for differences in suborder dispersal capabilities.

Results: Lower levels of connectivity and fewer nearest neighbours negatively impacted abundance, species richness, and composition of dragonflies (p values < 0.01, R² = 0.18-0.70). Adult dragonfly abundance had a stronger positive relationship with connectivity than species richness. In particular, the abundance of adult dragonfly Leucorrhinia frigida, found almost exclusively at natural ponds, had a positive relationship with connectivity. Connectivity and the number of nearest neighbours had no significant impact on damselflies apart from a slight negative relationship between connectivity and species richness (p value = 0.02, R² = 0.11). Natural ponds had significantly higher levels of connectivity when compared to stormwater ponds.

Conclusions: Our results suggest that dragonflies are positively affected by increased connectivity in an urban landscape, with no benefit of connectivity to damselflies at the scale measured. We recommend intentional planning of urban stormwater pond networks, where individual ponds can act as stepping stones, incorporated with strategic inclusion of beneficial land cover types.

Supplementary information: The online version contains supplementary material available at 10.1007/s10980-024-01817-z.

Keywords: Anisoptera; Circuitscape; Dispersal; Fragmentation; Urban ecology; Zygoptera.