Old field colonization by native trees and shrubs following land use change: Could this be Victoria’s largest example of landscape recovery?

Abstract

Summary Natural regeneration of farmland areas following landuse change has the potential to reinstate native vegetation and landscape processes across larger scales than intentional works. However, few examples of large‐scale natural regeneration have been reported from southern Australia. In this study we use historical air photos to document the rate of establishment of natural regeneration in central Victoria following a change from agricultural to rural residential land use. In 2009, regrowth patches occupied 8185 ha, or 12.3% of the cleared landscape in the study region, mostly on relatively low fertility soils. Most of this area (6216 ha) supported Cassinia shrubland, with eucalypts encroaching as patches get older. On average, native vegetation has regenerated over nearly 1800 ha every decade since the mid‐1960s. If this trend continues, regrowth will occupy 20% of infertile soils on private land by 2025. This region now appears to support one of the largest examples of old field succession recorded from south‐eastern Australia. Regrowth patches are likely to provide many conservation benefits, although little information exists on habitat values provided by regrowth shrublands. Since regeneration is on private land, perceptions of whether regrowth is ‘good’ or ‘bad’ will vary according to landholder goals, as will future management of regrowth patches. Consequently, considerable ecological and social research is required to understand the ecosystem services and disservices which regrowth provides to both landholders and biota.

Trajectory of change in land cover and carbon stocks following European settlement in Tasmania, Australia

“…In south eastern Australia and other 'neo-European' regions, biomass has increased in remnant forests and woodlands (Birdsey et al, 1993;Asner et al, 2003;Gibbons et al, 2008;Geddes et al, 2011;Prior et al, 2013). This trend was not evident in our study, but we did detect high density of Acacia species with small diameters in the understory of open forests.…”

Empirically validating a dense woody regrowth ‘problem’ and thinning ‘solution’ for understory vegetation

“…Prolific recruitment of one or few woody plant species commonly occurs where agricultural production or intensive resource extraction has ceased on land formerly occupied by woodlands and forests (Doherty, 1998;Geddes et al, 2011;Gifford and Howden, 2001;Lunt, 1998;Lunt et al, 2006;Rumpff et al, 2011;Wallin et al, 2004). Hereafter we refer to this phenomenon as ''dense woody regrowth''.…”

“…The negative impacts of high stand density may include suppression of understory floristic richness and cover (Aguiar et al, 1996;Briggs et al, 2005;Harrington and Edwards, 1999;Hobbs and Mooney, 1986;Lett and Knapp, 2003;McHenry et al, 2006;Price and Morgan, 2008;Wienk et al, 2004), reduction in stand growth rate (Dwyer et al, 2010a;Kenkel, 1988;McHenry et al, 2006;Sala et al, 2005;Vesk et al, 2008), delayed provision of desirable habitat features such as large boughs and hollows (Vesk et al, 2008), reduced stand fecundity (Vesk et al, 2010), and increased risks of fire, pathogens and insect attack (Sala et al, 2005;Wallin et al, 2004) and soil degradation (McHenry et al, 2006). There is also concern that regrowth stands may stabilise as degraded novel ecosystems (Cramer et al, 2008;Fensham, 2008;Geddes et al, 2011). Eventually, dense stands will self-thin (Kenkel, 1988;Olson et al, 2014;Westoby, 1984).…”

“…states predating European arrival (Eyre et al, 2011;Gibbons et al, 2010;Gibbons and Freudenberger, 2006;Jackson et al, 2000;Parkes et al, 2003;Wallin et al, 2004). In Australia for example, spontaneous woody regrowth is positively received while the plants are young but there is concern about the biodiversity and habitat value of these simplified stands as they age (e.g., Geddes et al, 2011;Kyle and Duncan, 2012). Dense woody regrowth is considered problematic because it is presumed to retard or exclude desirable biodiversity and habitat values.…”

Learning from agri-environment schemes in Australia: Investing in biodiversity and other ecosystem services on farms

“…Another possibility is that positive changes in the extent of native ecosystems, consistent with the objectives of agri-environment schemes, are occurring spontaneously due to declining extent of agricultural production and land use changes (Kyle and Duncan 2012;Geddes et al 2011). Government investment in agri-environment schemes may have only marginal benefit over the improving background trend (e.g.…”