Nanangroe Plantation Plot Network: The Value of Countryside Elements in the Conservation of the Threatened Arboreal Marsupial Squirrel Glider Petaurus norfolcensis in Agricultural Landscapes of South-eastern Australia - the Disproportional Value of Scattered Trees, 2005

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 (‘elements’) is increasingly recognised. In association with the Nanangroe Plot network in the South-West Slopes of New South Wales, 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 actual usage was relative to predicted levels of usage. The usage of ‘elements’ by gliders was largely explained by their availability, however 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. (Crane, M.J., Lindenmayer, D.B., Cunningham, R.B., 2014. 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. PLOS One. 9(9): e107178 DOI: 10.1371/journal.pone.0107178).

人类活动，尤其是农业活动，已重塑了全球绝大多数陆地生态环境。在这些人为景观中，存在多种残存半自然生境，我们将其统称为乡村生境要素（countryside elements）。乡村生境要素（以下简称“要素”）的生境价值正日益受到学界认可。本研究依托新南威尔士州西南坡的Nanangroe样地网络，针对一种受威胁的澳大利亚树栖有袋类——松鼠滑翔负鼠（Petaurus norfolcensis）所利用的四类乡村生境要素，量化其相对价值：包括路边线性残遗植被、本土植被斑块、散生树木以及人工栽植林木。本研究分析了家域（home range）面积与各类要素可获得性之间的关联，同时验证了松鼠滑翔负鼠对要素的实际利用是否与理论预期利用水平相符。松鼠滑翔负鼠对各类要素的利用程度在很大程度上取决于其可获得性，但研究发现它们更偏好本土植被斑块与散生树木。我们发现，随着散生树木覆盖面积的增加，松鼠滑翔负鼠的家域面积会显著缩小；而路边线性残遗植被或本土植被斑块覆盖面积的增加则会产生相反的效应。本研究证实，所有四类乡村生境要素均被松鼠滑翔负鼠所利用，因此均在该物种的保护中发挥着作用，但其相对价值存在差异。本研究表明，有必要对乡村生境要素的保护价值进行评估，从而将其纳入农业景观的整体管理框架之中。本研究证实了散生树木具有不成比例的高生态价值，强调了在生物多样性保护政策与管理实践中，需专门纳入并强化散生树木的保护与自然更新工作。（引自：Crane MJ, Lindenmayer DB, Cunningham RB, 2014. 澳大利亚东南部农业景观中乡村生境要素对濒危树栖有袋类松鼠滑翔负鼠的保护价值——散生树木的不成比例高价值. PLOS ONE, 9(9): e107178. DOI: 10.1371/journal.pone.0107178）