A history of hubris – Cautionary lessons in ecologically sustainable forest management

Logging is one of the most important forms of native-forest exploitation and can have substantial impacts on biodiversity and key ecosystem services. Here we briefly contrast logging operations in temperate and tropical forests and then highlight several challenges for understanding the ecological impacts of logging. We argue that many logging studies are conducted at small spatial scales or over inadequate time periods, and are biased against finding significant negative impacts. This is because of confounding environmental differences between logged and unlogged forests as well as the prolonged nature of forest stand development. Human perceptions of logging also can be biased by the ‘shifting baseline’ phenomenon, and by an incorrect perception that logging operations approximate natural disturbance regimes. We argue that the ecological impacts of logging can be more challenging to detect than is often appreciated, and that forest managers and decision-makers should be cautious when weighing the arguments of pro-logging lobbies.     

Regrowth forests on abandoned agricultural land: A review of their habitat values for recovering forest fauna

Human land use has modified the structure and function of terrestrial landscapes throughout much of the world, with cropping and livestock grazing the major drivers of landscape change. In many tropical, sub-tropical, temperate and Mediterranean regions, regrowth forests regenerate naturally on abandoned agricultural land if human disturbance declines. With the exception of some tropical forest literature, the broader ecological and conservation literature has largely ignored the potential of regrowth forests to facilitate passive landscape restoration and the recovery of fauna communities in fragmented agricultural landscapes. This paper addresses this deficiency by reviewing the available global evidence of fauna recovery in regrowth forest from 68 papers, identifying the main gaps in current knowledge, and providing directions for further research. The majority of reviewed studies focus on regrowth in tropical regions, which often contain large areas of mature forest. Species’ utilisation of regrowth forest is highly variable and is particularly influenced by land-use history, an important determinant of the structural and compositional characteristics of regrowth forests. While site-scale (<1 ha) forest structure and floristic diversity were frequently studied, only 11 studies considered the spatial configuration and context of habitat patches and just two studies explicitly considered landscape structure. Based on this review, six key research questions are posed to direct future research on this important issue. We conclude that a broader perspective of the role of regrowth forest in the landscape is required if we are to realise the potential benefits of regrowth forest for passive landscape restoration and fauna conservation and recovery.     

Effects of land management on the abundance and richness of spiders (Araneae): A meta-analysis

Human land use, through forest management and conversion of natural habitats into agroecosystems, has often resulted in loss of biodiversity. Spiders are important predators in terrestrial ecosystems, biological control agents against pests in agroecosystems and forests, and useful indicators due to their sensibility to changes in habitat structure and microclimate. Effects of land use on spiders have been reviewed several times but existing reviews are narrative and usually focused on one single kind of management. We summarize the impacts of land use on spider abundance and species richness using meta-analysis. The main ecosystems where the effect of management on spiders has been studied were forests, agroecosystems and rangelands (including meadows and grasslands). Although our survey retrieved studies from all parts of the world and climatic zones, a dominance of studies from temperate habitats in Europe and North America was evident. The meta-analysis showed negative effects on spider species richness and abundance for agroecosystems and rangelands, but were less evident for forests. From 10 kinds of land management identified, all but forest plantation showed effects on spider richness or abundance. These land management scenarios affected either species richness (forest fragmentation and logging, farmland abandonment, and miscellaneous management including plowing, cutting and fire), or spider abundance (forest fragmentation, forest fire, conventional farming, insecticides, grazing, and farmland abandonment), but not both. Edge effects had contrasting effects depending on the ecosystem, affecting spider species richness in agroecosystems and abundance in rangelands and forests. Direct destruction of spiders or negative effects on habitat heterogeneity or prey populations were the most likely causes of the negative effects detected.     

Prospects for biodiversity conservation in the Atlantic Forest: Lessons from aging human-modified landscapes

Recent global assessments have shown the limited coverage of protected areas across tropical biotas, fuelling a growing interest in the potential conservation services provided by anthropogenic landscapes. Here we examine the geographic distribution of biological diversity in the Atlantic Forest of South America, synthesize the most conspicuous forest biodiversity responses to human disturbances, propose further conservation initiatives for this biota, and offer a range of general insights into the prospects of forest species persistence in human-modified tropical forest landscapes worldwide. At the biome scale, the most extensive pre-Columbian habitats across the Atlantic Forest ranged across elevations below 800 masl, which still concentrate most areas within the major centers of species endemism. Unfortunately, up to 88% of the original forest habitat has been lost, mainly across these low to intermediate elevations, whereas protected areas are clearly skewed towards high elevations above 1200 masl. At the landscape scale, most remaining Atlantic Forest cover is embedded within dynamic agro-mosaics including elements such as small forest fragments, early-to-late secondary forest patches and exotic tree monocultures. In this sort of aging or long-term modified landscapes, habitat fragmentation appears to effectively drive edge-dominated portions of forest fragments towards an early-successional system, greatly limiting the long-term persistence of forest-obligate and forest-dependent species. However, the extent to which forest habitats approach early-successional systems, thereby threatening the bulk of the Atlantic Forest biodiversity, depends on both past and present landscape configuration. Many elements of human-modified landscapes (e.g. patches of early-secondary forests and tree monocultures) may offer excellent conservation opportunities, but they cannot replace the conservation value of protected areas and hitherto unprotected large patches of old-growth forests. Finally, the biodiversity conservation services provided by anthropogenic landscapes across Atlantic Forest and other tropical forest regions can be significantly augmented by coupling biodiversity corridor initiatives with biota-scale attempts to plug existing gaps in the representativeness of protected areas.     

Sustaining biodiversity conservation in human-modified landscapes in the Western Ghats: Remnant forests matter

Human-modified tropical landscapes under semi-natural or agro-ecosystems often harbor biodiversity of significant conservation value. In the Western Ghats of India, these ecosystems also provide connectivity between protected areas and other remnant forests. We investigated the conservation value of these landscapes and agro-ecosystems using results from 35 studies covering 14 taxonomic groups. Large, conspicuous taxonomic groups and tree-covered land-use types have received much focus in this area of research in the Western Ghats. We computed a response ratio defined as the log ratio of species richness in human land use to species richness in forest control site from 17 studies. In a meta-analysis, we investigated variation of this ratio across studies with respect to three variables: taxonomic group, the land-use type sampled and the extent of forest cover within the study landscape. Higher forest cover within the landscape emerged as a major positive influence on biodiversity in human-modified landscapes for vertebrates and vegetation while no patterns emerged for invertebrates. Our results suggest that loss of remnant forest patches from these landscapes is likely to reduce biodiversity within agro-ecosystems and exacerbate overall biodiversity loss across the Western Ghats. Conservation of these remnant forest patches through protection and restoration of habitat and connectivity to larger forest patches needs to be prioritized. In the densely populated Western Ghats, this can only be achieved by building partnerships with local land owners and stakeholders through innovative land-use policy and incentive schemes for conservation.     

A multi-taxa assessment of nestedness patterns across a multiple-use Amazonian forest landscape

Understanding how biodiversity is partitioned among alternative land-uses is an important first step for developing effective conservation plans in multiple-use landscapes. Here, we analysed nestedness patterns of species composition for nine different taxonomic groups [dung beetles, fruit-feeding butterflies, orchid bees, scavenger flies, leaf-litter amphibians, lizards, bats, birds and woody plants (trees and lianas)] in a multiple-use forestry landscape in the Brazilian Amazon containing primary, secondary and Eucalyptus plantation forests. A formal nestedness analysis was performed to investigate whether species-poor land-uses were comprised of a subset of species from more diverse forests, and the extent to which this pattern varied among taxa. At the landscape-scale the species-by-sites matrices were significantly nested for all nine taxonomic groups when both sites and species were sorted to maximally pack the species/occurrence matrix and, except for orchid bees when sorted by land-use intensity (primary forest to Eucalyptus plantation). Different patterns emerged when we conducted pairwise analyses of nestedness between the three forest types: (a) most of the taxonomic groups were nested in accordance with increased land-use intensity; (b) neither orchid bees nor leaf-litter amphibians from secondary forest made up a significant nested subset of primary forest species, although species found in Eucalyptus plantation sites were nested within secondary forest communities; and (c) lizards from Eucalyptus plantations were not a nested subset of either primary or secondary forest. Our findings emphasize the complex nature of patterns of species occupancy in tropical multiple-use forestry landscapes, and illustrate that there may be no easy solutions to questions regarding the conservation value of secondary and exotic plantation forests.     

General management principles and a checklist of strategies to guide forest biodiversity conservation

Many indicators and criteria have been proposed to assess the sustainable management of forests but their scientific validity remains uncertain. Because the effects of forest disturbances (such as logging) are often specific to particular species, sites, landscapes, regions and forest types, management “shortcuts” such as indicator species, focal species and threshold levels of vegetation cover may be of limited generic value. We propose an alternative approach based on a set of five guiding principles for biodiversity conservation that are broadly applicable to any forested area: (1) the maintenance of connectivity; (2) the maintenance of landscape heterogeneity; (3) the maintenance of stand structural complexity; and (4) the maintenance of aquatic ecosystem integrity; (5) the use of natural disturbance regimes to guide human disturbance regimes.We present a checklist of measures for forest biodiversity conservation that reflects the multi-scaled nature of conservation approaches on forested land. At the regional scale, management should ensure the establishment of large ecological reserves. At the landscape scale, off-reserve conservation measures should include: (1) protected areas within production forests; (2) buffers for aquatic ecosystems; (3) appropriately designed and located road networks; (4) the careful spatial and temporal arrangement of harvest units; and (5) appropriate fire management practices. At the stand level, off-reserve conservation measures should include: (1) the retention of key elements of stand structural complexity (e.g., large living and dead trees with hollows, understorey thickets, and large fallen logs); (2) long rotation times (coupled with structural retention at harvest); (3) silvicultural systems alternative to traditional high impact ones (e.g., clearcutting in some forest types); and (4) appropriate fire management practices and practices for the management of other kinds of disturbances.Although the general ecological principles and associated checklist are intuitive, data to evaluate the effectiveness of many specific on-the-ground management actions are limited. Considerable effort is needed to adopt adaptive management “natural experiments” and monitoring to: (1) better identify the impacts of logging operations and other kinds of management activities on biodiversity, and; (2) quantify the effectiveness of impact mitigation strategies; and (3) identify ways to improve management practices.     

Assessing landscapes: a case study of tree and shrub diversity in the seasonally dry tropical forests of Oaxaca, Mexico and southern Honduras

Tropical dry forests, with their distinct and economically important diversity, are acknowledged conservation priorities because of alarming rates of forest conversion. Whilst it is realised that terrestrial conservation requires an understanding of landscape level patterns of diversity, forests are rarely assessed accordingly. Here we demonstrate that, in the case of the seasonally dry tropical forests of the Pacific watershed of Mesoamerica, landscape level assessment of woody diversity can inform decision making relevant to both between-landscape and within-landscape prioritisation. We report floristic surveys of dry forest landscapes in Oaxaca, Mexico and southern Honduras. It is noted that these forests are floristically similar to other seasonally dry tropical forests in the neotropics. By calculation of Genetic Heat Indices, a relative measure of the concentration of restricted range species in a sample, we determine that the conservation of the tree diversity of the coastal lowlands of Oaxaca should be prioritised over that of southern Honduras. The current conservation status of forested areas in Oaxaca is briefly described. We suggest that the greater degree of anthropogenic disturbance in southern Honduras may explain the relative lack of restricted range species there. We argue that some forest fallows can act as analogues of mature forest and therefore landscape elements other than mature forest need to be included in forest conservation assessments. We conclude that diversity sampling of any forest type should not be limited to mature forests, but extended to other elements of forested landscapes.     

A multi-region assessment of tropical forest biodiversity in a human-modified world

The fate of much of the world’s terrestrial biodiversity is linked to the management of human-modified forest landscapes in the humid tropics. This Special Issue presents the first pan-tropical synthesis of research on the prospects for biodiversity in such systems, with eight individual regional summaries covering Mesoamerica, Amazonia, Atlantic forest of South America, West Africa, Madagascar, Western Ghats, Southeast Asia and Oceania. Two additional papers compare the state of conservation science in tropical forests with both temperate forests and savannah systems. This overview paper provides a comparative analysis of the threats and opportunities facing tropical forest biodiversity, thereby helping to identify the most pressing areas of future research and region-specific factors that contribute towards the effectiveness of individual conservation initiatives. While many of the threats facing tropical forest biodiversity are commonplace they vary markedly in their relative importance across different regions. There is a critical lack of comparable data to understand scale dependent processes, or the relative importance of varying geographic and historical contexts in determining present-day patterns. Conservation science has a key role to play in safeguarding the future of tropical forest biodiversity, but needs to become more effectively embedded in the context of real-world conservation challenges and opportunities. Significant progress can be achieved by improving the cost-effectiveness of research as well as the exchange of ideas and data amongst scientists working in different, often isolated parts of the world. We hope this special issue goes some way top achieving this exchange of knowledge.     

Recovery of woody plant diversity in tropical rain forests in southern China after logging and shifting cultivation

Logging and intense shifting cultivation have caused major degradation of tropical forests and loss of biodiversity. Understanding the direct and indirect effects of those land uses on plant biodiversity is essential to the restoration of tropical forests. We compared the species diversity, community composition and basal area of all stems ?1 cm dbh among 18 1-ha tropical lowland and montane rain forest plots with a well-recorded long-term history of shifting cultivation and logging on Hainan Island, south China. We also explored the relative importance of disturbance and environmental factors in determining forest recovery. We found that the species density and diversity in old growth forests were higher than in shifting cultivation fallows (55 years old) but lower than in logged forests (35–40 years since logging). The species composition of shifting cultivation fallows was distinct from other forest types but logged forests were similar to old growth forests, especially in lowland forests. Disturbance intensity was the most frequently important factor in determining species composition, species density, diversity, and basal area accumulation. Soil nutrient availability explained some of the variation in species composition and diversity. Stem density was related to multiple factors including disturbance history, soil nutrients, and distance to old-growth forest. In general, we found that disturbance intensity was a better predictor of forest structure and diversity than edaphic environmental variables, highlighting the importance of human impacts in shaping tropical forest successional pathways.     

Mapping community change in modified landscapes

Habitat loss is not randomly distributed across modified landscapes, yet spatial patterns of habitat cover are not routinely combined with biodiversity data when assessing or predicting the biodiversity impacts of land use change. Here, we convert point observations of more than 28,000 beetles from 851 species into a continuous biodiversity surface representing the similarity of ecological communities relative to that of pristine forest, effectively integrating on-the-ground biodiversity data with remotely sensed land cover data to predict the magnitude of community change in a modified landscape. We generated biodiversity surfaces for both present-day and pre-human landscapes to map spatial patterns of change in a diverse ecological community to calculate the combined biodiversity impacts of habitat loss and fragmentation that accounts for the exact spatial pattern of deforestation. Our spatially-explicit, landscape-scale index of community change shows how the fine-scale configuration of habitat loss sums across a landscape to determine changes in biodiversity at a larger spatial scale. After accounting for naturally occurring within-forest heterogeneity, we estimate that the conversion of 43% of forest to grassland in a 1300 km² landscape in New Zealand resulted in a 47% change to the beetle community.     

Landscape-level effects on avifauna within tropical agriculture in the Western Ghats: Insights for management and conservation

A critical handicap to tropical biodiversity conservation efforts in agroecosystems is the unknowns regarding the influence of landscape-scale factors on the persistence of species. To address these uncertainties, we explored two essential landscape-scale questions, within India’s biologically-rich Western Ghats, examining two nearby human-dominated landscapes that dramatically differed in their pattern of land cover. First, how does the proximity of intact forest patches affect bird community composition within agricultural landscapes? Second, can simple remote sensing-derived measures (brightness, wetness, and NDVI) be used to estimate native bird species composition within those landscapes? In both landscapes, as distance to intact forest decreased, the similarity in bird community composition between agricultural areas and intact forest increased. This suggests that the retention of tropical forest bird communities within human-dominated landscapes critically depends on the maintenance of nearby intact forest. In an answer to the second question, the remote sensing measures correlated with forest-affiliated avian species richness in only one of the two landscapes, reflecting an ecological difference between the two in the response of forest bird species to local agricultural conditions. In the landscape where a correlation was found, there was high variation in vegetative structure, which strongly impacted both the remote sensing measures and forest bird species richness. In the other landscape, forest species richness strongly correlated with changes in tree species composition in the agriculture, a factor that could not be detected by the remote sensing metrics. In order to successfully conserve biodiversity in tropical agricultural landscapes, our findings show that it is essential to conserve intact forest within those landscapes and to understand the effect of local agricultural practices on species.     

Changes in Collembola richness and diversity along a gradient of land-use intensity: A pan European study

Changes in Collembola richness and diversity along a land-use intensity gradient were studied in eight European countries (Portugal, Spain, France, Switzerland, Hungary, UK, Ireland and Finland). In each country a set of six 1 km² land-use units (LUUs) were selected forming a gradient ranging from natural forest to agricultural dominated landscapes, passing through mixed-use ones. In addition to data on Collembola, detailed information regarding landscape diversity and structure was collected for each LUU. A total of 47,774 individuals were identified from 281 species. Collembola reacted not only to changes in the diversity of the landscape, but also to the composition of that diversity and the area occupied by each land-use type at each LUU. Although species richness patterns were not concordant among the different countries, the total number of species per LUU (landscape richness) was generally higher in natural forests and mixed-used landscapes, and lower in agricultural dominated landscapes. Moreover, high richness and diversity of Collembola at each LUU were associated with a diverse landscape structure, both in terms of number of patches and patch richness. Despite this comparable species richness between mixed-use landscapes and those dominated by natural forests, average species richness on forested areas (local richness) decreased along the gradient, showing that forest patches on mixed-use landscapes support a lower richness than in landscapes dominated by forest. This aspect is important when addressing the role of native forests in structuring biodiversity in disturbed and fragmented landscapes. Although a diverse landscape can support a high biodiversity, the results suggest that intensive fragmentation should be avoided with the risk of collapsing local species richness with the consequent result for regional biodiversity.     

Conserve or convert? Pan-tropical modeling of REDD–bioenergy competition

The land competition between tropical bioenergy plantations and payments for forest carbon conservation (e.g., through an international scheme for Reduced emissions from deforestation and forest degradation, REDD+) is modeled using spatially explicit data on biofuel feedstock (oil palm and sugar cane) suitability and forest biomass carbon stocks. The results show that a price on the (avoided) carbon emissions from deforestation at the same level as those from fossil fuel use makes clearing for high yielding bioenergy crops unprofitable on about 60% of the tropical evergreen forest area. For the remaining 40% deforestation remains the most profitable option. Continued profitability of forest clearing is most pronounced for oil palm bioenergy systems in Latin America and Africa, with REDD+ making deforestation for sugar cane plantations unprofitable on 97% of evergreen forest land. Results are shown to be relatively robust to assumptions regarding potential yields and to the addition of a ‘biodiversity premium’ on land use change emissions. While REDD+ may play an important role in stemming biodiversity loss and reducing carbon emissions from tropical deforestation in the near future, in the longer run reliance on a system that values forests solely for their carbon retention capacities poses a serious risk. It is imperative that the institutions and policies currently being established as part of REDD+ readiness activities are resilient to future changes in the incentive structures facing tropical forest countries due to, e.g., climate policy induced demand for biofuels.     

Differences in bird diversity between two swidden agricultural sites in mountainous terrain, Xishuangbanna, Yunnan, China

This study took a comparative look at the relationship between human-altered landscapes and bird diversity in two mountainous swidden (slash and burn) agricultural sites in Xishuangbanna, Yunnan, China. Over the course of 3 years (1998-2000) the authors used line-transect identification surveys in the two regions, Mengsong and Jinuo, where four different habitats were surveyed: 6-year fallow fields; traditional economic forests; monsoon evergreen broadleaf forests; and montane rain forests. Data were analyzed for species diversity, richness (family, genera, species), co-occurrence (family, genera, species), characterization of migratory status and feeding habits. Both of these study areas are inhabited by minority groups (Hani and Jinuo) that employ swidden agriculture as their main form of economic activity. The forest landscape in the Jinuo ethnic region is quickly transforming due to changing agricultural practices, and as a result bird diversity and richness are declining, while the Hani ethnic region (Mengsong), with a stable form of traditional swidden agriculture, is maintaining a high diversity and richness of birds. The greatest differences in bird diversity between the two sites occurred in the traditional economic forests and the 6-year fallow fields where the Hani region had a much greater richness and diversity. The two natural forest types (monsoon evergreen broadleaf forests and montane rain forests) were more similar in richness and diversity and also maintained the greatest richness and diversity of the four forest types analyzed. The transformation of healthy forests into degraded landscapes is one of the major impacts of human activity on the natural environment, which is posing a great threat to biodiversity. This study looks at the bird diversity of the two regions and tries to take into account how humans can extract economic benefits while preserving ecological benefits, such as a landscape that allows biodiversity to thrive.     

Impacts of selective logging on canopy and ground assemblages of tropical forest butterflies: Implications for sampling

Commercial selective logging is a major cause of habitat disturbance in Southeast Asian rainforests, yet despite much research there is little consensus on impacts of disturbance on biodiversity. There is also little consensus on the most appropriate methods for sampling tropical species, making it difficult to draw general conclusions from published studies. For example, many studies have used butterflies to assess impacts of selective logging but sampling has usually been conducted at ground level and the canopy fauna has often been ignored. In this study, we investigate the importance of sampling in the canopy by using fruit-baited traps to investigate impacts of selective logging on Nymphalid butterflies in primary forest and forest selectively logged 15 years previously in Sabah (Malaysian Borneo). Analysing combined data from canopy (≈25 m above ground level) and ground-level traps showed significantly lower diversity in selectively logged forest. However, this difference was not observed when data from only ground traps were analysed. Primary forest supported a butterfly assemblage comprising species with more restricted geographical ranges, and thus higher conservation value, compared with selectively logged forest. This result was observed regardless of whether or not canopy data were included in this analysis. We conclude that sampling in the canopy is critical when producing species inventories, but of little importance when determining the impacts of selective logging on restricted-range species.     

Rapid deforestation and fragmentation of Chilean Temperate Forests

The temperate forests of Chile are classified a biological “hotspot” as a result of their high species diversity and high endemism. However, they are being rapidly destroyed, with significant negative impacts on biodiversity. Three land-cover maps were derived from satellite imagery acquired over 25 years (1975, 1990 and 2000), and were used to assess the patterns of deforestation and forest fragmentation in the coastal range of south-central Chile. Between 1975 and 2000, there was a reduction in natural forest area of 67% in the study area, which is equivalent to an annual forest loss rate of 4.5% per year using a compound-interest-rate formula. Forest fragmentation was associated with a decrease in forest patch size, which was associated with a rapid increase in the density of small patches (<100 ha), and a decrease in area of interior forest and in connectivity among patches. Since the 1970s, native forest loss was largely caused by an expansion of commercial plantations, which was associated with substantial changes in the spatial configuration of the native forests. By 2000, most native forest fragments were surrounded by highly connected exotic-species plantations. The assessment of forest loss and fragmentation provides a basis for future research on the impacts of forest fragmentation on the different component of biodiversity. Conservation strategies and land use planning of the study area should consider the spatial configuration pattern of native forest fragments and how this pattern changes over time and space at landscape level.     

The value of forest strips for understorey birds in an Amazonian plantation landscape

Remnant forest strips are frequently proposed as valuable conservation tools in fragmented tropical landscapes, yet we currently lack evidence to evaluate their potential conservation value for native biota. We examined the potential value for understorey forest birds of 30-year-old riparian and terra firme (unflooded) primary forest strips within a large silvicultural landscape in the north-east Brazilian Amazon, where the matrix is dominated by Eucalyptus plantations. We conducted mist-netting in eight forest strips connected to continuous forest (four of each forest type), with a total of 24 replicate sampling sites located near to (<1 km), far from (2.5-9 km), and within undisturbed forest controls (i.e. 16 samples within the strips, and 8 in controls). Bird communities in both strip types changed with increasing distance along forest remnants into the plantation matrix. Matrix-embedded samples were characterised by a higher representation of birds typical of secondary growth forest but not those typical of the Eucalyptus-dominated matrix. While the long-term viability of the bird populations in these remnants remains unclear, our data demonstrate that forest strips can provide important habitat for many bird species that are otherwise rarely found outside primary forest. Forest strips therefore provide an important tool to enhance biodiversity conservation in plantation landscapes. The relative practical ease with which these areas can be selected and maintained means that the protection of forest strips as part of a wider conservation strategy is likely to have particular appeal to policy makers and landscape managers working in the human-dominated tropics.     

Fauna conservation in Australian plantation forests - a review

A review of the value for fauna of conifer and eucalypt plantations in Australia is presented. Five key reasons highlight a need for wildlife conservation as part of plantation management. These are: (1) The plantation estate in Australia is set to triple in the coming decades, and where new plantations are located and how they are managed will influence the biota that currently exist in such landscapes. This is particularly critical in many semi-cleared former grazing landscapes where the establishment of new plantations is focused. This is because: (1) (a) native vegetation communities in these areas are poorly represented in the existing reserve system, and, (b) uses such as wood and pulp production need to be balanced with other management values such as wildlife conservation. (2) The maintenance of some elements of the biota within plantations could have benefits for key ecosystem processes like pest control. (3) Although some species cannot be conserved in plantation-dominated landscapes, many species can be through the adoption of (sometimes minor) modifications to forest management. (4) The maintenance (or loss) of biota in plantations is relevant for moves toward ecological standards and the certification of plantations in many parts of the world. And, (5) simple plantation forestry which has a narrow and intensive management focus on producing a forest crop for a limited array of purposes, may not meet societal demands for a range of outputs from plantations in addition to wood and pulp. It also may not be congruent with the principles of ecological sustainability.Our review showed that almost all research undertaken in Australian plantations, both in conifers and eucalypts, highlighted the importance of landscape heterogeneity and stand structural complexity for fauna conservation. At the landscape level, patches of retained native vegetation, strips of riparian vegetation, dams, open and clearing areas can significantly increase the number of native species that occur within plantations. Some species that occur in these areas can also use adjacent planted areas, a result common to conifer and eucalypt plantations. The spatial juxtaposition of stands of varying ages throughout plantation landscapes also can contribute to the maintenance of some populations of native taxa. At the stand level, structural complexity is also important for fauna with many species responding positively to the presence of native understorey plants, the presence of windrowed logs, and logging slash left on the forest floor.The management of plantations to promote landscape heterogeneity and stand structural complexity will, in many cases, involve trade-offs that will influence wood and pulp production. The extent to which this occurs will be dependent on the objectives of plantation management and how far they extend toward the complex plantation forestry model to incorporate social and environmental values in addition to wood and pulp production.     

Beyond the forest edge: Ecology, diversity and conservation of the grassy biomes

Forests and grassy vegetation (savannas and grasslands) are alternative ecosystem states in many tropical landscapes. Relative to forests the grassy ecosystems are poorly known and poorly conserved, partly because they were thought to be products of forest clearance. However many grasslands have proved to be ancient. Commensurate with their antiquity, grassy biomes have distinct suites of plant and animal species that contribute a large fraction of the diversity of forest-grassland mosaics. Grasslands differ strikingly from forests in their ecology and in the nature of threats to their future. Here we highlight the high biodiversity value of grassy biomes and, in contrast to tropical forests, we illustrate the importance of fire in maintaining these systems. We discuss the major threats to, and consequences for, biodiversity in these regions including land clearance and elevated CO₂-driven forest expansion. Finally we focus on the difficulties of grassland restoration. A new approach to understanding and conserving grassy ecosystems, free from cultural prejudices of the past, is long overdue.