Evaluating the relative importance of patch quality and connectivity in a damselfly metapopulation from a one‐season survey

Abstract

The area‐and‐isolation paradigm, which has been the primary focus of metapopulation research, may not hold in some animal metapopulations if within‐patch preference is more important than patch area or connectivity. Recently, regression analyses have been used to evaluate the effect of patch connectivity and various patch qualities including area. However, their relative importance is not easy to determine, because patch qualities and connectivity are often spatially autocorrelated. In this paper, we try to evaluate the relative importance of within‐patch quality, patch connectivity and spatial autocorrelation using variation partitioning methods from community ecology. We constructed three regression models: within‐patch quality, PCNM (principal coordinates of neighbor matrices) and patch connectivity based on a one‐season survey of a damselfly Copera annulata metapopulation. The contribution of within‐patch quality was larger than that of connectivity. There was no prominent effect of patch area. We conclude that the area‐and‐isolation paradigm is not applicable to this C. annulata metapopulation. The spatial autocorrelation extracted by PCNM had the largest contribution; it contained almost all of the variation of connectivity and overlapped with variation explained by within‐patch quality. Connectivity corresponded most closely to medium‐scale spatial structure captured by PCNM (ca 640 m). The mean effective dispersal scale was estimated to be 53 m. Within‐patch quality, debris accumulation and vegetation cover in the pond corresponded with the medium and small (ca 201 m) spatial scales from PCNM, though we could not clearly explain the cause of this correspondence. We believe that our method will contribute to quick and effective evaluation of spatial and non‐spatial aspects of metapopulation.

Effects of landscape and patch-level attributes on regional population persistence

“…Previous research characterizing the independent or interactive influences of patch quality indicated that this variable can exert significant effects on local population performance, with some studies demonstrating that local habitat quality can have the highest independent effect on local population dynamics (Betzholtz, Ehrig, Lindeborg, & Dinnétz, 2007;Jaquiery et al, 2008;Mortelliti et al, 2010;Pöyry, Paukkunen, Heliölä, & Kuussaari, 2009;Root, 1998;Yamanaka et al, 2009). Similarly, across the patch attribute gradients present in this study, the independent effects of patch quality had a greater influence on the risk of regional extinction than the common indices of patch size and proximity.…”

Taxonomic uncertainty of a highly endangered brook damselfly, Copera tokyoensis Asahina, 1948 (Odonata: Platycnemididae), revealed by the mitochondrial gene genealogy

“…Exact test of population differentiation showed significant difference (P \ 0.05) among three C. tokyoensis populations that are closely located (\20 km). For the dispersal ability of C. annulata, Yamanaka et al (2009) estimated the generational mean dispersal distance to be 53 m. This very short dispersal behavior connects neighboring patches and the patches make clusters at the scale of the medium spatial category (640 m; Yamanaka et al 2009). If these two Copera species shows similar tendency of small range dispersion, the genetic differentiation of C. tokyoensis might be explained by the low-dispersal ability of females.…”

Environmental Characteristics accounting for Odonate Assemblages in Rural Reservoir Ponds in Japan

“…The colonization of odonates in isolated habitat patches is limited by the dispersal capability and behavior of each species 1,8,15 . It is also limited by the differences in landscape structure among the habitats 16,28,41 . The effect of the differences in connectivity and landscape structure among ponds on regional odonate populations is an important area of future research.…”

“…Previous field studies on factors affecting odonate species have identified the importance of aquatic and riparian vegetation 7,31 , predatory fish 21,22,25,27 , water quality 3,4 , landscape structure 16,20,29,41 , and spatial autocorrelation 15 . However, these studies have investigated either a single or several environmental factors.…”