Barking up the right tree: comparative use of arboreal and terrestrial artificial refuges to survey reptiles in temperate eucalypt woodlands

Abstract

Context Artificial refuges (cover boards) are a popular method to survey and monitor herpetofauna worldwide. However, one limitation of using artificial refuges in terrestrial environments is the low detection rates of arboreal species. Furthermore, destructive search techniques can damage critical microhabitat such as exfoliating rock or flaking bark of mature trees. Aim We tested a non-destructive, passive method of sampling arboreal reptiles in fragmented agricultural landscapes in south-eastern Australia. Methods We installed 84 artificial bark refuges consisting of strips of non-toxic, closed-cell foam attached to eucalypt trees in 13 patches of remnant vegetation. We used Bayesian statistics to compare differences in detection rates among artificial bark refuges, terrestrial artificial refuges and active searches of natural habitat over a 4-year period. Key results Active searches combined with terrestrial artificial refuges detected the highest number of reptile species, including several cryptic fossorial species. Artificial bark refuges detected, on average, 132 times more individuals of the arboreal southern marbled gecko, Christinus marmoratus, than did terrestrial refuges. Gecko abundance patterns were related to tree characteristics such as tree size, bark thickness and stand basal area, as well as survey year. Conclusions Traditional survey methods such as terrestrial cover boards, in combination with active searches of natural habitat, may significantly underestimate counts for arboreal gecko species. Implications Artificial bark refuges provide a cost-effective, non-destructive and durable method for surveying and monitoring arboreal reptiles in woodland environments over short to medium time frames. Foil-backed, closed-cell foam has broad application for use in spatial capture–recapture studies and long-term monitoring of arboreal reptiles. This method also may be effective for procuring records of threatened arboreal geckos or as a solution for providing temporary habitat in ecological restoration projects.

Temporal trends in reptile occurrence among temperate old-growth, regrowth and replanted woodlands

“…For example, C . marmoratus is arboreal and often found on large trees with flaking bark [ 12 , 20 ]–attributes more likely to occur in old-growth woodland relative to other broad structural vegetation types [ 28 ]. More detections of individual species would be required to allow construction of complex statistical models that included measures of detailed vegetation structure and analyses beyond ours of broad vegetation structure types (i.e., old growth woodland, regrowth woodland, and replantings).…”

“…This is likely to be closely linked with the habitat requirements of those species. For example, C. marmoratus is arboreal and often found on large trees with flaking bark [12,20]-attributes more likely to occur in old-growth woodland relative to other broad structural vegetation types [28]. More detections of individual species would be required…”

“… 18 , 19 ]. Negative impacts of land clearing would be expected given the loss of key components of habitat in temperate woodland environments such as large old trees [and associated bark habitats; see 20 ], and fallen timber [ 8 , 21 ]. Threats from agriculture in general are estimated to affect over 12% of Australian reptiles [ 3 ] and more than 45% of species listed under IUCN threat categories [ 22 ].…”

Ornamental Phoenix palm trees as habitat for fauna in the Mediterranean Region – results from a full year monitoring

“…Artificial refuges for reptiles (arboreal and terrestrial refuges) were installed on tree trunks and on the ground between palm trees. Arboreal refuges consisted of squares of synthetic fibre mats (size 1 m x 1 m), placed around the trunk and tied with a string (following Michael et al (2018) ). Terrestrial refuges consisted of squares of roofing cardboard (size 0.5 m x 0.5 m), placed on the ground and fixed in corners, for example, with stones (following Vlašín and Mikátová (2015) ).…”