Distribution and abundance of hollow-bearing trees in urban forest fragments

Abstract

a b s t r a c tHabitat structures, such as hollow-bearing (i.e. cavity-bearing) trees, are globally recognised as important forest features for wildlife conservation and for providing important structural heterogeneity in natural and modified landscapes. The depletion of structural resources, such as hollow-bearing trees, within a landscape, may therefore be limiting to biota where no other functional substitutes exist. We surveyed 45 natural forest remnants across the rapidly urbanising City of Gold Coast, south-east Queensland, Australia to quantify the distribution and abundance of hollow-bearing trees. Tree and tree-hollow variables were quantified within the selected 91 plots. In total 6048 trees from 34 eucalypt species were sampled and 916 hollow-bearing trees containing 2159 hollows were recorded. The average hollow-bearing tree density (37.5 ± 3.13/ha) was much higher than those found in other studies within Australia. Hollows were more prevalent in large trees and the majority (50.4%) of hollows were bayonets (10 cm). Dead and decaying trees also had a greater likelihood of having a hollow than healthy trees. Our results highlight the value of urban forest remnants in maintaining the functional capacity of urban landscapes for biodiversity by protecting hollow-bearing trees as habitat resources. This information will assist conservation managers and planners to establish sound adaptive management plans to conserve biodiversity and ecosystem function in natural and modified landscapes.

“Set and forget” does not work when it comes to fissure roosts carved into live trees for bats

“…We conducted a field trial to test the efficacy of carved fissures, which had entrances designed to replicate natural cracks and crevices that develop in the trunks and branches of live trees (Lindenmayer et al 2000; Treby & Castley 2015), and are commonly used by bats (Kunz & Lumsden 2003). We found that the entrances to all 174 of the carved fissures across 83 trees were closed by wound wood growth within 1–5 years of installation, while some were closed by kino flow within as little as 3 months.…”

Charting the Research Terrain for Large Old Trees: Findings from a Quantitative Bibliometric Examination in the Twenty-First Century

“…The research aims to support the conservation and sustainable management of old trees by assessing their abundance, distribution, and diversity across forest ecosystems and landscapes to identify hotspots and declines [7,30]. In addition, quantifying diverse habitat associations helps to locate and protect large, old, hollow-bearing trees [53]. Furthermore, analyzing the causes of mortality informs the stewardship of vulnerable heritage trees [39].…”

Arborists and Urban Foresters Support for Urban Wildlife and Habitat Sustainability: Results of an Urban Ecology-Focused Survey of Arborists

“…While this method directly contrasts with general conceptions of tree risk reduction in the urban forest [36], the retainment of hollows on both live and dead trees is understood to be a primary dependent factor in wildlife selection of habitat trees [68]. In urban ecology, a focused concern of wildlife habitat loss surrounds hollows and cavities [69,70]. If arborists are retaining wildlife snags that do not contain hollows/cavities or other beneficial tree features (nesting roosts, open branching structures, peeling bark), wildlife snags can miss key opportunities to provide benefits to urban wildlife [71,72].…”