Nigel I.J. Tucker

Bio: Nigel I.J. Tucker is an academic researcher. The author has contributed to research in topics: Biodiversity & Rainforest. The author has an hindex of 4, co-authored 5 publications receiving 121 citations.

Quantifying the biodiversity values of reforestation: perspectives, design issues and outcomes in Australian rainforest landscapes

Abstract: Following two centuries of land clearing, the past two decades have seen growing efforts to reestablish forest on formerly-cleared sites. While the immediate goals of reforestation vary, there is also a widespread expectation that one of its effects will be an improvement in “biodiversity value”. However, agreed standards concerning how this can be measured, and against what benchmarks it should be judged, are lacking. This paper describes a study of biodiversity development in different types of rainforest reforestation in tropical and subtropical eastern Australia. It provides information on the responses of rainforest fauna and also discusses key issues of survey design and methodology that, if ignored, may limit the effectiveness of monitoring programs. The nature of rainforest, its history within Australia, and its role as fauna habitat are briefly reviewed. Modern deforestation and human land use, and various reforestation pathways (including regrowth, timber plantation, and ecological restoration projects) are described. Then, design principles, biodiversity measurements, and issues relating to their choice are discussed. These include: spatial scale; site selection and replication in relation to environmental variation; reference sites; the array of potentially measurable biotic and process variables, and spatio-temporal measurement scales. Finally we explore analytical options and present selected findings, using univariate and multivariate approaches, and comparing simple species richness, functional groupings, and analyses of taxonomic composition. Rainforest biodiversity value is defined as the development of a rainforest-like set of biota and ecological processes. Reforested sites were generally intermediate between pasture and rainforest reference sites in the measured components of rainforest biodiversity value. Many components had been rapidly (by around 10 years) acquired by ecological restoration sites, although it is clear that some components will take decades or longer to develop. The results also show: (1) the existence of production/ biodiversity trade-offs, in that sites managed for timber production acquired less biodiversity value than those planted for ecological restoration; (2) moderate correspondence across different indicator taxa when they are analysed for assemblage composition; (3) very little agreement among indicator taxa when overall richness is used; (4) a likelihood of important landscape and context effects. Long-term conservation of rainforest fauna will require rainforest restoration over substantial areas of currently denuded land. However, although rainforest restoration may often show reasonable success, it should not be viewed as an alternative to conserving existing remnants and advanced regrowth.

Biodiversity values of timber plantations and restoration plantings for rainforest fauna in tropical and subtropical Australia

Abstract: It has been suggested that timber plantations could play an important role in the conservation of biodiversity in cleared rainforest landscapes, not only because of their potential to cost-effectively reforest large areas of land, but also because they may provide habitat for rainforest plants and animals. However, this last claim is largely untested. In this study, we surveyed the occurrence of a range of animal taxa in monoculture and mixed species timber plantations and restoration plantings in tropical and subtropical Australia. We used the richness of ‘rainforest-dependent’ taxa (i.e., birds, lizards and mites associated with rainforest habitats) in reforested sites as our measure of their ‘biodiversity value’. We also examined whether the biodiversity value of reforested sites was correlated with habitat attributes, including plant species richness and vegetation structure and, further, whether biodiversity value was affected by the proximity of reforested sites to intact rainforest.

Conservation strategy for Lumholtz's tree-kangaroo on the Atherton Tablelands.

Abstract: Lumholtz’s tree-kangaroo (Dendrolagus lumholtzi) is a large (10 kg max.) arboreal marsupial endemic to the rainforests of north Queensland, Australia. According to museum records, community surveys and spotlighting data, the species is most abundant in higher elevation rainforests (above 700 – 800 m a.s.l.) on the Atherton Tablelands, particularly on fertile basalt soils (Newell 1999; Kanowski et al. 2001a, b). Clearing has reduced the area of this prime habitat for D. lumholtzi from approximately 66 000 ha to 25 000 ha. Extensive areas of prime habitat are now restricted to the Herberton Range on the western edge of the Tablelands (Fig 1).

Development of forest structure on cleared rainforest land in eastern Australia under different styles of reforestation

Abstract: Rainforests in eastern Australia have been extensively cleared over the past two centuries In recent decades, there have been increasing efforts to reforest some of these cleared lands, using a variety of methods, to meet a range of economic and environmental objectives However, the extent to which the various styles of reforestation restore structure, composition and ecological function to cleared land is not presently understood In this study, we develop and apply a method for quantifying the structural attributes of reforestation sites in tropical and subtropical Australia The types of reforestation studied were plantation monocultures, mixed species cabinet timber 2 plots, diverse restoration plantings and unmanaged regrowth Two age classes of reforestation were examined: ‘young’ (5 – 22 years), incorporating sites from all categories, and ‘old’ (30 – 70 years), in which only monoculture plantations and regrowth were represented A total of 104 sites were surveyed including reference sites in intact rainforest and pasture Intact rainforest was characterised by a suite of complex structural features including abundant special life forms (vines, epiphytes, hemi-epiphytes and strangler figs), a dense stand of trees in a range of size classes, a closed canopy, a shrubby understorey and a well-developed ground layer of leaf litter and woody debris These features were lost on conversion to pasture While all types of reforestation returned some elements of structural complexity to cleared land, young plantation monocultures, cabinet timber plots and young regrowth had a relatively simple structure These sites typically had a low density of woody stems, a relatively open canopy and grassy ground cover, and lacked large trees, coarse woody debris and most special life forms Restoration plantings and old regrowth were more complex, with a high density of woody stems, a relatively closed canopy and shrubby understorey Old monoculture plantations in the tropics had acquired many of the structural attributes of intact forest, however this was not the case in the subtropics, where plantations were subject to more intensive management The marked differences in structural complexity between sites suggest that the different types of reforestation practiced in eastern Australia are likely to vary considerably in their value as habitat for rainforest biota

Faunal response to revegetation in agricultural areas of Australia: A review

Abstract: Summary We reviewed the literature on fauna in revegetation in Australian agricultural areas. Of 27 studies, 22 examined birds, with few studies focusing on other faunal groups (four to six studies for each remaining group) and nine examined multiple groups. Existing evidence suggests that revegetation provides habitat for many species of bird and some arboreal marsupials. Species richness of birds was greater in revegetated areas that were large, wide, structurally complex, old and near remnant vegetation. Bats, small terrestrial mammals, reptiles and amphibians did not appear to benefit significantly from revegetation in the short term. Evidence to date suggests that revegetation is not a good replacement of remnant vegetation for many species. Key information gaps exist in the faunal response to (i) revegetation as it ages; (ii) different structural complexities of revegetation; (iii) revegetation that is composed of indigenous vs. non-indigenous plant species; and (iv) revegetation that is in riparian vs. non-riparian locations. In addition, little is known on the value of revegetation for declining or threatened fauna, or of the composition of fauna in revegetation. There is a need to better understand the balance between quantity of revegetation in the landscape, and the quality or complexity of revegetation at the patch scale. Based on current evidence, we recommend revegetation be conducted in patches that are large, wide and structurally complex to maximize the benefits to fauna.

Growing Plantation Forests

Abstract: 1 Plantation Forests.- 2 Biology of Plantation Growth.- 3 Growth Rates and Wood Quality.- 4 Choosing the Species and Site.- 5 Establishment.- 6 Nutrient Management.-7 Stand Density and Initial Spacing.- 8 Thinning.- 9 Pruning.- 10 Pests.- 11 Diseases.- 12 Tree Breeding.- 13 Mixed-species Plantations.- 14 Conclusion.- References.