Time lags in provision of habitat resources through revegetation
Introduction
In many regions including Europe, North America and parts of Australia, de-intensification of land use and rehabilitation of agricultural lands is occurring with allocation of much human, biological and economic resources (Madsen, 2002, Stanturf and Madsen, 2002, Vallejo et al., 2006). Most effort has been directed towards restoration and afforestation using woody vegetation. While passive restoration (management to encourage recruitment from persistent mature individuals or from seed banks) is often desirable, active replanting with seed or seedlings is frequently required (Honnay et al., 2002, Vallejo et al., 2006, Vesk and Dorrough, 2006). In Australia, recent years have seen significant replanting of native trees and shrubs in rural landscapes (National Heritage Trust, 2005). In 2006, the community-based organization Greening Australia planted 2.6 million seedlings and direct seeded 1776 km of rows of native species (Greening Australia, 2007). While most revegetation is multifunctional in purpose, and control of soil salinity and provision of shelter for stock have been primary aims for much Australian revegetation, a key goal has been the conservation of native biodiversity. However, little is known about the ecological benefits of revegetation (Vesk and Mac Nally, 2006), information that is crucial for effective revegetation planning. Frequently, monitoring focuses on implementation, with tenuous links to ecological outcomes (Lake, 2001, Freudenberger et al., 2004, Vesk and Mac Nally, 2006). More useful are monitoring of fauna occupancy and abundance or using space-for-time substitutions of sites revegetated at differing but relatively short time frames (5–25 yr) (Biddiscombe, 1985, Ryan, 1999, Fisher, 2001, Martin et al., 2004, Cunningham et al., 2007, Kavanagh et al., 2007, Loyn et al., 2007). Both approaches fail to provide robust predictions of the long-term responses (50–200 yr) because most revegetation activities are recent.
There is scope for exploring development of revegetation over longer timeframes. Historical plantations date back to the late 1800s in Victoria (Bannear, 1997), albeit not intended specifically for biodiversity benefits. One approach is survey fauna in these plantations to assess the ecological outcomes of current revegetation efforts. However, this assumes that such plantations are a good proxy for current revegetation such that faunal responses would be expected to be similar between the historic and current revegetation at equivalent ages. There are reasons why this may not be valid. Some of the ways in which historical plantations differ from contemporary ones include: intention (shelter, woodlots); landscape context (isolated versus adjacent to remnants); tree species (many early plantings were Eucalyptus cladocalyx, which has a highly restricted natural range); planting designs (stem densities, understorey, spatial configuration). For these reasons, historical plantations may make for poor habitat that is unlikely to support populations of fauna. Many plantings, both historical and contemporary, are small, isolated from remnant native vegetation and have high perimeter to area ratios (Freudenberger et al., 2004, Radford and Bennett, 2007), properties commonly associated with low probabilities of occupancy (Mac Nally et al., 2000b, Westphal et al., 2003a), population persistence (Fahrig and Merriam, 1994, Mac Nally, 2007b), and dominance by aggressive, territorial species (e.g. noisy miners, Manorina melanocephala) (Clarke and Oldland, 2007, Maron, 2007).
An alternative is to focus on change in vegetation structure, with the eventual aim of modelling habitat resources, independent of spatial configuration of the planting and the surrounding landscape (Dennis et al., 2003). Many fauna are known to have strong associations with habitat resources such as boughs or hollows for nesting (Sedgwick and Knopf, 1986, Gibbons and Lindenmayer, 2002), flowers for nectar provision (Mac Nally and McGoldrick, 1997, Wilson and Bennett, 1999), and fallen timber for both foraging and shelter (Mac Nally, 2006, Mac Nally and Horrocks, 2007a). There is extensive literature on provision of timber resources in relation to time and silvicultural practices in managed forests (Smith et al., 1997). However, there has been limited research on the habitat resources provided for fauna by revegetation (Hobbs et al., 2003) and none has examined how these resources may change as vegetation matures. Knowledge about the provision of habitat resources over time can be incorporated into habitat suitability models for the purpose of projecting suitability beyond the ages of empirical datasets of faunal occupancy in revegetation (Mac Nally, 2007a). Here, we present results of a survey of habitat resources within revegetated areas of known age ranging from about 5–130 yr. We have three main aims: to demonstrate the timelags in the process of habitat restoration; to assess the effects of management, namely planting density, on this process; and to assess the functionality of the replanted habitat.
Section snippets
Study location and site selection
Surveys were conducted on the inland slopes and adjacent plains of the Great Dividing Range in south-eastern Australia from October 2005 to August 2006. The area lies within the 300–700 mm annual rainfall zone (Fig. 1). All sites were on sedimentary soils. Sites affected by past mining disturbance were avoided. Sites <1 ha and shelter-belt style plantings (linear strips) were excluded.
Site selection was based primarily on replanting age. We aimed to sample representatively with respect to age of
Results
Planting tubestock has been the most common method of active revegetation and direct seeding also has long been employed (Fig. 2). Sites ranged in size from 0.3 to 235 ha (median 2.9 ha, mean 13.8 ha).
Discussion
Our data extends to much older sites than any other published study of revegetation in Australia. The three major contributions are: (1) documentation of the time course of provision of habitat resources necessary for faunal (specifically birds and mammals) occupation of these sites; (2) analysis of the effect of management, through planting density, on this time course; and (3) analysis of the functionality of planted sites in terms of recruitment and life form diversity.
Acknowledgements
Sites were located following extensive consultation with the North-Central, Goulburn-Broken, North-East and Mallee Catchment Management Authorities, the Victorian Departments of Sustainability and Environment, Primary Industries and Education, Parks Victoria, the University of Melbourne School of Forestry, Trust for Nature, Landcare, Greening Australia, farm forestry organizations, and a number of private landholders. Thanks to the many landholders who allowed access to their properties and
References (74)
- et al.
Evaluating simultaneous effects of three anthropogenic effects on a floodplain-dwelling marsupial Antechinus flavipes
Biological Conservation
(2007) - et al.
Eucalypt plantings on farms: use by insectivorous bats in south-eastern Australia
Biological Conservation
(2006) - et al.
Eucalypt plantations as habitat for birds on previously cleared farmland in south-eastern Australia
Biological Conservation
(2007) - et al.
Scattered trees in rural landscapes: foraging habitat for insectivorous bats in south-eastern Australia
Biological Conservation
(2005) Longer-term response to experimental manipulation of fallen timber on forest floors of floodplain forest in south-eastern Australia
Forest Ecology and Management
(2006)- et al.
Landscape-scale conservation of an endangered migrant: the Swift Parrot Lathamus discolor in its winter range
Biological Conservation
(2000) - et al.
The conservation value of mesic gullies in dry forest landscapes: avian assemblages in the box-ironbark ecosystem of southern Australia
Biological Conservation
(2000) - et al.
Forecasting the impacts of habitat fragmentation. Evaluation of species-specific predictions of the impact of habitat fragmentation on birds in the box-ironbark forests of central Victoria, Australia
Biological Conservation
(2000) The Danish afforestation programme and spatial planning: new challenges
Landscape and Urban Planning
(2002)Threshold effect of eucalypt density on an aggressive avian competitor
Biological Conservation
(2007)
A conceptual model of land use effects on the structure and function of herbaceous vegetation
Agriculture, Ecosystems & Environment
Diameter-basal area ratio as a practical stand density measure for pruned plantations
Forest Ecology and Management
The clock is ticking – revegetation and habitat for birds and arboreal mammals in rural landscapes of southern Australia
Agriculture, Ecosystems & Environment
Tree hollows as a resource for wildlife in remnant woodlands: spatial and temporal patterns across the northern plains of Victoria, Australia
Pacific Conservation Biology
Bird populations of farm plantations in the Hotham River valley
W. A. Western Australian Naturalist
Landscape equivalency analysis: methodology for estimating spatially explicit biodiversity credits
Environmental Management
Penetration of remnant edges by noisy miners (Manorina melanocephala) and implications for habitat restoration
Wildlife Research
Reptile and arboreal marsupial response to replanted vegetation in agricultural landscapes
Ecological Applications
Towards a functional resource-based concept for habitat: a butterfly biology viewpoint
Oikos
Conservation of fragmented populations
Conservation Biology
Avifauna changes along a Eucalyptus regeneration gradient
Emu
Foraging and aggressive behaviour of the Regent Honeyeater Xanthomyza phrygia in northern New South Wales
Emu
Predicting the biodiversity benefits of the Saltshaker Project, Boorowa, NSW
Ecological Management and Restoration
Prior distributions for variance parameters in hierarchical models
Bayesian Analysis
Posterior predictive assessment of model fitness via realized discrepancies
Statistica Sinica
No net loss of fish habitat: a review and analysis of habitat compensation in Canada
Environmental Management
Faunal use of bluegum (Eucalyptus globulus) plantations in southwestern Australia
Agroforestry Systems
Ecological perspectives for the restoration of plant communities in European temperate forests
Biodiversity and Conservation
Eucalypt plantings on farms benefit woodland birds in south-eastern Australia
Austral Ecology
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Present address: CSIRO Sustainable Ecosystems, Canberra, ACT, Australia.