Comparisons of microhabitat use of Schlegel’s Japanese gecko (Gekko japonicus) among three populations and four land cover types

Abstract

Background: The effective use of habitats is essential for the successful adaptation of a species to the local environment. Although habitats exhibit a hierarchical structure, including macro-, meso-, and microhabitats, the relationships among habitats of differing hierarchy have not been well studied. In this study, we studied the quantitative measures of microhabitat use of Gekko japonicus from three field populations in Japan: one at Tsushima Island, one at Nishi Park, Fukuoka, and one at Ohori Park, Fukuoka. We investigated whether land cover type, a higher hierarchical habitat component, was associated with quantitative microhabitat use, a lower hierarchical component, in these populations. Results: The substrate temperature where we located geckos (SubT) and the distance from the ground to the gecko (Height) were significantly different among the three populations. In particular, SubT on Tsushima Island was lower than it was in the other two populations. Irradiance at gecko location and Height were significantly different among the land cover types. In particular, Height in evergreen needleleaf forest was significantly lower than that in deciduous broadleaf forest. Furthermore, significant interactions between population and land cover type were observed for the SubT and Height variables. Conclusions: The quantitative measures of microhabitat use of G. japonicus varied with population and land cover type, which exhibited significant interaction effects on microhabitat use variables. These results suggest that higher hierarchical habitat components can affect the quantitative measures of lower hierarchical microhabitat use in nocturnal geckos.

Patterns of morphological variation in the Schlegel’s Japanese gecko (Gekko japonicus) across populations in China, Japan, and Korea

“…For those variables, some may be important for local morphological adaptation to given environments. In urban habitats, G. japonicus may encounter different food sources, refuge types, wall conditions, and individual competition levels compared to their natural forest habitats (McKinney 2002;Parris 2016;Kim et al 2018), which facilitates the adaptive differentiation of particular morphological features. At the moment, although exactly related previous results are not available in geckos, there is a growing body of evidence showing significant causal relationships between morphological variation and specific environmental components.…”

“…Although three populations in Busan were geographically close to each other, the populations are considered independent based on the home range (~140 m 2 ) of G. japonicus (Park 2019) and urban barriers. We only used adult geckos with a snout-vent length (SVL) over 45 mm to compare similar age groups and reduce possible developmental effects on the morphology (Kim et al 2018). We determined the sex of each individual based on the relative size of the cloacal spurs (Tokunaga 1984).…”

“…Based on results indicating high within-population genetic variation and little divergence among populations, the authors suspected that extensive gene exchange occurred among local populations. In Korea, studies were recently performed on G. japonicus's distribution and habitat use (Kim et al 2018(Kim et al , 2019, mitochondrial genome (Kim et al 2016), and shelter selection in an indoor vivarium (Park et al 2018). Nevertheless, it remains a mystery how G. japonicus populations were established across Korea.…”

Prediction of present and future distribution of the Schlegel’s Japanese gecko (Gekko japonicus) using MaxEnt modeling

“…The five environmental variables used in the model were selected based on previous studies and our expert knowledge from field survey of G. japonicus: altitude, slope, land cover type, Normalized Difference Vegetation Index (NDVI), and distance to the nearest urban and built-up area (Fattahi et al 2014;Zhang et al 2014;Acheson and Kerr 2018;Kim et al 2018;Ribeiro et al 2018). The altitude and slope for each location were extracted from the WorldClim database (ver.…”

“…In Korea, populations are only found in southern coastal cities such as Busan, Changwon, and Mokpo (Lee et al 2004;Kim et al 2017). Only few basic ecological and genetic studies have been done on G. japonicus (Toda et al 2003;Zhang et al 2009;Kim et al 2018Kim et al , 2019Park et al 2019). Recent concerns regarding area of origin and gentic relationships among populations are growing due to range expansions of G. japonicus in Korea and Japan, possibly due to anthropogenic factors or climate change (Toda et al 2003;Kim et al 2017).…”