City of Darebin Heritage Study Volume 1 Draft Thematic

DAREBIN HERITAGE STUDY STAGE 28 DAREBIN’S NATURAL HERITAGEIntroductionThis chapter provides an overview of Darebin’s natural heritage in the present, in contrast tothe picture provided in Chapter 1 Creating Darebin, before the time of European arrival. Therange of activities and processes that have altered the environment are described in 4.5 Alteringthe environment. Moves to protecting and managing the environment are discussed in 5.5Creating public landscapes and 7.6 Appreciating and defending the environment. This chapterfollows the themes in the Australian Natural Heritage Charter of ecosystems, biodiversity andgeodiversity and provides a summary of Darebin’s natural heritage.8.1 Ecosystem valuesAccording to the Natural Heritage Charter, Ecosystem means a dynamic complex of organismsand their non-living environment, interacting as a functional unit.Most of Darebin falls into the Victorian Volcanic Plain bioregion, but the higher parts ofBundoora Park and Mount Cooper, and the LaTrobe University and Bundoora sections of themunicipality are part of the Gippsland Plain bioregion.Landscape structure and connectivityThe process of settlement of Darebin has changed the landscape from having multidirectionalconnections between a mosaic of ecosystems that extended across the whole municipality (andfurther) to one where small fragments of ecosystems remain, many completely surrounded bysuburbia.This fragmentation of the landscape has reduced its habitat values even more than suggested bythe massive reduction in the total area of natural ecosystems to an estimated 2%. According toBennett (1999):Habitat fragmentation is a dynamic process that has three main components: an overall loss ofhabitat in the landscape, reduction in the size of remaining blocks, and increased isolation bynew forms of land use. Changes to the pattern of habitats in the landscape result in changes toecological processes that in turn affect the status of the flora and fauna. Effects of habitatfragmentation on wildlife include: loss of species in fragments, changes to the composition offaunal assemblages, and changes to ecological processes that involve animals. Isolation of habitatsis a fundamental consequence of fragmentation. A range of evidence shows that isolation, and thedegree of spatial isolation, have negative impacts on many populations and communities. Thenegative effects of isolation are attributed to the decreased opportunity for movement of animalsto and from other habitats.While there is not a lot of evidence to demonstrate how effective habitat corridors can be, it issafer to assume that a connected landscape with corridors is preferable to a fragmentedlandscape. Anderson & Jenkins (2006) identify two basic types of corridors - the landscapecorridor which provides multidirectional connections between a mosaic of ecosystems thatextend over an area of tens to thousands of square kilometres, and linear or habitat movementcorridors which provide a single continuous (or near continuous) link between two or moreusually larger habitat blocks. The landscape corridor that Darebin was is no more. Manyremnant habitats are poorly connected if at all to other habitat areas, reducing their ability tomaintain animal and plant populations, especially over time. Some linear corridors remain, andthese should be protected and enhanced. There is much scope to re-create linear corridors atleast along the main waterways.Strategies to enhance the connectedness of habitats in Darebin should form part of Stage 5 ofthe Heritage Study.132