The effects of dispersal and recruitment limitation on community structure of odonates in artificial ponds

Abstract

I examined the effects of isolation on the structure of both adult and larval dragonfly (Odonata: Anisoptera) communities forming at physically identical artificial ponds over two years. Isolation, whether measured by distance to the nearest source habitat or by connectivity to multiple sources, was significantly negatively related to the species richness of dragonflies observed at and collected in these ponds. These results indicate that dispersal and recruitment limitation acted as filters on the richness of communities at these artificial ponds. The richness of larval recruits in artificial ponds was lower than the richness of adult dispersers observed at ponds, and distance from a source habitat explained a greater fraction of the variation in larval than adult richness (83 and 50%, respectively). These results and a male biased sex-ratio in adults observed at artificial ponds suggest that isolated habitats may be more recruitment limited than observations of dispersers would suggest. A Mantel test indicated there was a spatial component to the composition of communities forming in tanks, and that distance between tanks and community dissimilarity (1-Jaccard's) were significantly positively related (r 0/0.52). This pattern suggests that their position with respect to alternative source environments influenced the composition of the communities that recruited into these ponds. These results provide further evidence of recruitment limitation in this system. Results from this study highlight the importance behavior ally limited dispersal may have in taxa morphologically capable of broad dispersal and suggest that the role of dispersal and recruitment limitation may be critical in shaping community structure across habitat gradients that include variation in habitat duration. S. J. McCauleyDept of Ecology and Evolutionary Biology, Univ. of Michigan, Ann Arbor, MI 48109-1048, USA Factors that affect community structure are often dispersal and recruitment, may also affect species divided into two general categories, local (niche-composition within local sites, by placing an upper assembly) processes and regional (dispersal-assembly) boundary on species richness and by limiting the processes (Ricklefs 1987). Both sets of processes can numbers of species arriving at sites suitable for local act as filters on the composition of local communities establishment (MacArthur and Wilson 1967, Cornell (Poff 1997). Local processes, including species interac-and Lawton 1992, Srivastava 1999). Understanding the tions and abiotic tolerances, can determine whether extent to which communities may be structured by species are able to establish and maintain populations processes at either level is a critical question in ecology once they have reached a habitat. Regional factors, and is central to the field of metacommunity ecology including the size of the species pool as well as (Leibold et al. 2004).

The influence of habitat integrity and physical-chemical water variables on the structure of aquatic and semi-aquatic Heteroptera

“…They increase the typical flow of the Cerrado rivers, which is associated with group plasticity, causing an intermediate disturbance response such as the one predicted by CONNELL (1978). Furthermore, communities are also subject to local processes, which may determine whether or not species are fit to settle and keep their population once they have found a habitat (MCCAULEY 2006). Nevertheless, the HII has shown a mild, yet positive relationship with the estimated richness of Gerromorpha species.…”

Habitat isolation moderates the strength of top‐down control in experimental pond food webs

“…Here, we experimentally examined the 1 E-mail: jchase@wustl.edu effects of habitat isolation on the diverse food web that assembles in small fishless pond communities. Habitat isolation is known to influence the diversity and abundance of several groups of pond organisms, including many species (e.g., diving beetles, dragonflies) that are top predators in these food webs (Wilcox 2001, McCauley 2006, 2007, Shulman and Chase 2007. We used mesocosms to simulate pond habitats and manipulated isolation among mesocosms.…”

Evaluating the effects of landscape configuration on site occupancy and movement dynamics of odonates in Iowa

“…The decision to disperse involves a trade-off between potentially living longer at an already-occupied site with competition for limited resources or risking survival to disperse and colonize a new, unoccupied site (Angelibert and Giani 2003). Odonates are believed to be philopatric (McPeek 1989, Angelibert andGiani 2003), and individuals won't disperse if it is too risky (McCauley 2006) or if they currently occupy suitable breeding habitat (Corbet 1999). Distance to the nearest suitable habitat is the primary factor limiting odonate dispersal (Conrad et al 1999;McCauley 2006).…”

“…Odonates are believed to be philopatric (McPeek 1989, Angelibert andGiani 2003), and individuals won't disperse if it is too risky (McCauley 2006) or if they currently occupy suitable breeding habitat (Corbet 1999). Distance to the nearest suitable habitat is the primary factor limiting odonate dispersal (Conrad et al 1999;McCauley 2006). Iowa has lost >98% of its original wetland and grassland habitats to agricultural development resulting in an extremely fragmented landscape leaving remaining habitats highly isolated.…”