EUROPEAN JOURNAL OF ENTOMOLOGYENTOMOLOGY ISSN (online): 1802-8829 Eur. J. Entomol. 113: 217–232, 2016 http://www.eje.cz doi: 10.14411/eje.2016.027 REVIEW Dragonfl ies and damselfl ies (Odonata) in urban ecosystems: A review GIOVANNA VILLALOBOS-JIMÉNEZ, ALISON M. DUNN and CHRISTOPHER HASSALL School of Biology, University of Leeds, Woodhouse Lane, LS2 9JT, Leeds, United Kingdom; e-mails: [email protected], [email protected], [email protected] Key words. Odonata, urban ecology, city, anthropogenic stressors, odonates, dragonfl ies, damselfl ies, biodiversity, ecotoxicology, behaviour, life history, phenotypic variation, ecological traps, bioindicators Abstract. The expansion of urban areas is one of the most signifi cant anthropogenic impacts on the natural landscape. Due to their sensitivity to stressors in both aquatic and terrestrial habitats, dragonfl ies and damselfl ies (the Odonata) may provide in- sights into the effects of urbanisation on biodiversity. However, while knowledge about the impacts of urbanisation on odonates is growing, there has not been a comprehensive review of this body of literature until now. This is the fi rst systematic literature review conducted to evaluate both the quantity and topics of research conducted on odonates in urban ecosystems. From this research, 79 peer-reviewed papers were identifi ed, the vast majority (89.87%) of which related to studies of changing patterns of biodiversity in urban odonate communities. From the papers regarding biodiversity changes, 31 were performed in an urban-rural gradient and 21 of these reported lower diversity towards built up city cores. Twelve of the cases of biodiversity loss were directly related to the concentrations of pollutants in the water. Other studies found higher concentrations of pollutants in odonates from built-up catchments and suggested that odonates such as Aeshna juncea and Platycnemis pennipes may be candidate indicators for particular contaminants. We conclude by identifying current research needs, which include the need for more studies regarding behavioural ecology and life-history traits in response to urbanisation, and a need to investigate the mechanisms behind diversity trends beyond pollution. INTRODUCTION gate current research on the impacts of urbanisation using Urbanisation is one of the main drivers of ecosystem odonates as a model group. First, we will present a brief change. The expansion of urban areas is a main cause of overview on the impacts of urbanisation on terrestrial and many environmental stressors: (i) removal of native vege- freshwater ecosystems, then we conduct a systematic lite- tation leading to degradation and fragmentation of the nat- rature review regarding odonates in urban environments ural landscape, (ii) modifi cation of hydrological systems and outline the plausible effects on odonates, followed by through water extraction for human use, (iii) increase of the use of odonates as bioindicators, the conservation value local minimum temperature creating a “heat island” effect, of urban wetlands for odonates, a summary of evolution- and (iv) accumulation of pollutants to a point at which the ary strategies for species to cope with urban stressors, and environment cannot fully process and degrade them, caus- fi nally we conclude by identifying research needs. ing eutrophication and affecting biogeochemical cycles THE EFFECTS OF URBAN STRESSORS ON (Grimm et al., 2008; McDonald, 2008). Moreover, the es- TERRESTRIAL AND FRESHWATER ECOSYSTEMS timated percentage of the world population living in urban areas now exceeds 50% (Grimm et al., 2008) and almost The wide range of impacts associated with urbanisation 60% will be living in urban areas by the year 2030 (Seto et indicates that it exerts a considerable effect on terrestrial al., 2012; Güneralp & Seto, 2013). Given the range of im- biodiversity. Most studies show that species richness and pacts and rapid growth of urban development, it is essen- evenness is reduced in highly urbanised regions, depend- tial that we understand in depth the implications for natural ing on the taxonomic group observed, degree of urbanisa- systems both in and around cities. Dragonfl ies and dam- tion, and spatial scale of analysis (McKinney, 2002, 2008). selfl ies (the Odonata) have been suggested as barometers For example, butterfl ies (Ruszczyk, 1987; Ruszczyk & for environmental change due to their sensitivity to other De Araujo, 1992; Blair & Launer, 1997) and ground ar- anthropogenic stressors such as climate change (Hassall, thropods (McIntyre et al., 2001) show this tendency. The 2015) and variation in habitat quality (Clark & Samways, general pattern of biodiversity decrease in cities is prob- 1996). However, the impacts of urbanisation on odonates ably due to the fact that over 80% of land in city cores remain poorly understood. In this review, we will investi- is covered by buildings and pavements, with the remain- Final formatted article © Institute of Entomology, Biology Centre, Czech Academy of Sciences, České Budějovice. An Open Access article distributed under the Creative Commons (CC-BY) license (http://creativecommons.org/licenses/by/4.0/). 217 Villalobos-Jiménez et al., Eur. J. Entomol. 113: 217–232, 2016 doi: 10.14411/eje.2016.027 ing area used for lawns, trees, and shrubs (Blair & Launer, sensitivity to a range of urban stressors means that odo- 1997), thus fragmenting the landscape and homogenising nate communities have the potential to act as barometers vegetation composition (Blair & Launer, 1997; Faeth et al., of environmental change in urban areas, as has been dem- 2011; Faeth et al., 2012; McKinney, 2002). However, plant onstrated successfully in South Africa for habitat quality biodiversity peaks at intermediate levels of urbanisation, (Clark & Samways, 1996) and as has been suggested for perhaps due to the high numbers of species associated with climate change (Hassall, 2015). In this review we outline suburban gardens (McKinney, 2008). the stressors associated with urban environments that have Urban freshwaters have not been explored as much as the potential to affect odonates considerably across their terrestrial urban ecosystems, despite the high degree of life cycle. vulnerability that freshwaters exhibit to the pressures of DRAGONFLIES AND DAMSELFLIES AS A MODEL urbanisation (Paul & Meyer, 2001; Dudgeon et al., 2006). SYSTEM Urban streams, for example, are usually modifi ed to carry out storm water into natural streams, washing away in- Dragonfl ies and damselfl ies (the Odonata) are highly dustrial and human wastes, as well as road runoff (For- suitable model organisms for the study of urban ecosys- man, 2014). Streams are subjected to toxins, temperature tems because (a) they are sensitive to different stressors, change, siltation, organic pollutants, and the replacement such as pollutants (Ferreras-Romero et al., 2009) and tem- of riparian vegetation and substrate for rocks or concrete perature changes (Hassall & Thompson, 2008), therefore and, consequently, insects, molluscs, crustaceans, and an- can be a powerful tool to assess the general conditions of nelids tend to have decreased species richness and abun- the city environment; (b) they are aquatic as larvae and ter- dance (Paul & Meyer, 2001; Forman, 2008, 2014; Vaughan restrial as adults, hence can be used as bioindicators in both & Ormerod, 2012). The presence of organic pollution has aquatic and terrestrial habitats (Oertli, 2008); (c) they have been associated with increased abundance of chironomids an important role as predators, hence have a wide range and oligochaetes, making them the dominant members of of interactions with different organisms in both aquatic urban stream communities (Campbell, 1978; Seager & and terrestrial ecosystems (Knight et al., 2005); (d) they Abrahams, 1990; Paul & Meyer, 2001). are ideal for studying movement through the landscape, as Ponds are very frequent in parks and gardens for aes- their adult stage exhibits a high dispersal ability and are thetic purposes and to improve human well-being (For- very conspicuous (Conrad et al., 1999), and (e) their bio- man, 2014; Hassall, 2014), and are greatly infl uenced by a diversity, ecology and evolutionary biology is well-docu- variety of factors such as the land use of the surroundings, mented, providing a robust foundation for drawing general the runoff to the pond, subsurface groundwater fl ow, and conclusions (Córdoba-Aguilar, 2008). shoreline conditions (Forman, 2014). Parks and gardens are LITERATURE REVIEW heavily managed and fertilisers are commonly used, and due to their limited capacity for the processing of pollut- We conducted a literature review of the prior work re- ants and nutrients, ponds often suffer from eutrophication garding urbanisation and odonates, in order to evaluate with an accompanying decline in biodiversity (Forman, the potential of odonates as a model system for studying 2014). However, the relative isolation of urban ponds gen- urbanisation. During January–April 2014, we used stand- erates a substantial degree of habitat heterogeneity. Each ardised search terms with three online databases: Web of pond possesses its own physical, chemical, and hydrologi- Science, Scopus and ScienceDirect. The words “urban” cal features, facilitating the presence of a range of species and “Odonata OR dragonfl * OR damselfl *” were searched of specialised habitat requirements, hence increasing the in title, keywords and abstract (except in Web of Science, differentiation among these ecosystems and the