Conserving Biodiversity in Brigalow Regrowth - School of ...

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How much vegetation? The main reason so many of our native animals have become rarer, and even threatened with extinction, is because we have removed much of their habitat. Less habitat means fewer individuals, leading to population decline. Smaller populations are at more risk of going extinct through chance events; in many regions, several species have disappeared altogether. So how much habitat do we need to retain in our landscape if we want to keep most of our wildlife? The answer is complicated, because different species need different types and amounts of habitat. However, there are some general patterns that we can use as rules-of-thumb in the absence of detailed, species-specific information. For example, research in southern Australian woodlands suggests that the number of bird species in the landscape declines most rapidly if vegetation cover drops below 10%. Yet work in the brigalow suggests that this threshold might be higher. In brigalow landscapes, more vegetation means more bird species at least up to 30% vegetation cover. Our research has shown that there is no clear target for the amount of woodland necessary to support diverse reptile communities in the brigalow. But we can say that landscapes with less than 20% native vegetation support much lower diversity and abundance of reptiles, particularly species that have limited ability to move across open country. Queensland Department of Environment and Resource Management As with birds, the more brigalow woodland in the landscape, the better the reptile community. This means that every effort to retain vegetation helps to maintain the richness of wildlife communities – and this is especially true in landscapes with less than 30% of the original vegetation remaining. It also means that every small increase in vegetation cover, such as through retention of regrowth vegetation, will help species return to the landscape. Actively encouraging the regeneration of brigalow regrowth in these landscapes is one of the best things that can be done for wildlife, with the aim of returning overall woodland cover to at least 30% wherever possible. All native vegetation contributes to wildlife habitat – and in landscapes with less remaining habitat, every bit is crucial MICHIALA BOWEN 14
CONSERVING BIODIVERSITY IN BRIGALOW LANDSCAPES Regrowth is important Regrowth represents a conservation bargain because regrowth can grow into mature woodlands without the large investment of time and resources associated with tree planting schemes. Brigalow has a remarkable capacity to regrow from root stock in the soil, sometimes even after a decade of cultivation. Long regarded as a nuisance by landholders, brigalow regrowth currently occupies large areas in the Brigalow Belt. In comparison to tree planting, brigalow regrowth offers a cost-effective and less labour-intensive means for conducting broad-scale habitat restoration. This does not mean that restoration of habitat is without costs for the landholder – the choice to allow brigalow regrowth to regenerate could result in lost production. An increasing number of government-funded schemes provide compensation funds to landholders who restore former production lands. The structure and floristic composition of brigalow regrowth vegetation is often very different from the original remnant woodlands. Above: The number of woodland dependent bird species occupying regrowth stands increases with woodland age. After 30 years, regrowth can support as many bird species as remnant woodlands. After clearing, young brigalow regrowth (≤15 years) is low, with no trees and few shrubs (apart from the brigalow itself). Intermediate age regrowth (16 – 30 years) exhibits characteristics overlapping both young and old regrowth, but is often more similar to old regrowth. Old regrowth (> 30 years) is taller, has fewer stems and a more ‘tree-like’ shape than the younger shrubby regrowth. Fallen timber, hollows and a complex ground and shrub layer are still missing from old regrowth and may take more than 100 years to develop. These differences in the characteristics of regrowth woodland compared with remnant brigalow mean that regrowth does not provide identical habitat as the original woodland. Over time, brigalow regrowth can develop into important habitat. Few woodland birds are able to use brigalow regrowth in the first couple of decades of growth, but after 30 years the regrowth can support the same number of species that are found in mature woodlands. This does not mean that only old regrowth is valuable for fauna. Long before it can provide habitat for a diverse range of species, it can provide other benefits such as providing movement pathways for species that cannot cross paddocks and crops. The dense shrubby structure of young regrowth is important breeding habitat and shelter for animals hiding from introduced predators like cats and foxes. Tiny birds like the superb and variegated fairy-wrens love to hide their nests in the young brigalow shrubs. Remnant CleareD Young regrowth (< 15 yrs) intermediate regrowth (15- 30 yrs) OLD regrowth (> 30 yrs) 15
Page 2 and 3: PARTNERS CONTRIBUTORS Associate Pro
Page 4 and 5: Foreword Times change. In 1960 when
Page 6 and 7: Brigalow Landscapes The Brigalow Be
Page 8 and 9: Between the Wars After WWI, develop
Page 10 and 11: threats to brigalow Although the br
Page 12 and 13: Scales of Habitat Management Managi
Page 16 and 17: Managing dense Brigalow regrowth: T
Page 18 and 19: Key habitat features What are the m
Page 20 and 21: Iconic species and their habitat WI
Page 22 and 23: limbs and under loose bark on old t
Page 24 and 25: LIST OF VERTEBRATE SPECIES recorded
Page 26 and 27: QUICK REFERENCE GUIDE 1. How much v

Conserving Biodiversity in Brigalow Regrowth - School of ...

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