The Value of Countryside Elements in the Conservation of a Threatened Arboreal Marsupial Petaurus norfolcensis in Agricultural Landscapes of South-Eastern Australia—The Disproportional Value of Scattered Trees

Abstract

Human activities, particularly agriculture, have transformed much of the world's terrestrial environment. Within these anthropogenic landscapes, a variety of relictual and semi-natural habitats exist, which we term countryside elements. The habitat value of countryside elements (hereafter termed ‘elements’) is increasingly recognised. We quantify the relative value of four kinds of such ‘elements’ (linear roadside remnants, native vegetation patches, scattered trees and tree plantings) used by a threatened Australian arboreal marsupial, the squirrel glider (Petaurus norfolcensis). We examined relationships between home range size and the availability of each ‘element’ and whether the usage was relative to predicted levels of use. The use of ‘elements’ by gliders was largely explained by their availability, but there was a preference for native vegetation patches and scattered trees. We found home range size was significantly smaller with increasing area of scattered trees and a contrasting effect with increasing area of linear roadside remnants or native vegetation patches. Our work showed that each ‘element’ was used and as such had a role in the conservation of the squirrel glider, but their relative value varied. We illustrate the need to assess the conservation value of countryside elements so they can be incorporated into the holistic management of agricultural landscapes. This work demonstrates the disproportional value of scattered trees, underscoring the need to specifically incorporate and/or enhance the protection and recruitment of scattered trees in biodiversity conservation policy and management.

The importance of scattered trees for biodiversity conservation: A global meta‐analysis

“…Scattered trees have many ecological functions in landscapes, for example, offering shelter and food sources for animals, enhancing landscape connectivity by acting as stepping stones, and functioning as nuclei for plant regeneration in disturbed landscapes (Crane, Lindenmayer, & Cunningham, ; Derroire et al., ; Fischer & Lindenmayer, ; Rossi, Garcia, Roques, & Rousselet, ). Moreover, scattered trees may enhance the provision of ecosystem services that might benefit farmers and owners of rural properties, such as pollination of crops, shading for cattle, regulation of nitrogen dynamics and carbon sequestration, herbaceous production, and wood provision (Barton et al., ; Belsky, ; Cottee‐Jones, Bajpai, Chaudhary, & Whittaker, ; Frost & McDougald, ; Hartel, Réti, & Craioveanu, ; Jackson, Strauss, Firestone, & Bartolome, ; Sanchez & Lindsell, ).…”

Do nest boxes in restored woodlands promote the conservation of hollow‐dependent fauna?

“…Indeed, revegetated areas often lack key attributes of vegetation structure like large old hollow‐bearing trees that take a long time to develop (Vesk et al ) and which provide crucial habitat structures that biota depend on for survival (e.g. hollows, fallen woody debris, and decorticating bark microhabitat) (Gibbons et al ; Fischer et al ; Crane et al ). A paucity of these key resources may mean that a significant proportion of the fauna that might otherwise inhabit areas of natural vegetation in agricultural areas will be absent (Flaquer et al ; Cunningham et al ).…”

Conserving and restoring endangered southern populations of the Squirrel Glider (Petaurus norfolcensis) in agricultural landscapes

“…Work by Crane et al . () in the south‐western slopes of NSW showed this was the case for the Squirrel Glider and found that only elements containing woody vegetation were used. Crane et al .…”

“…These landscape features are often termed countryside elements (Haslem & Bennett ; Crane et al . ). The role that different countryside elements play in the conservation of particular species varies (Haslem & Bennett ).…”

“…Crane et al . () recognized four distinct elements ‘linear roadside remnants’, ‘native vegetation patches’, ‘scattered trees’ and ‘tree plantings’. Countryside elements containing old growth Eucalyptus are particularly important.…”