Rainforest—eucalypt forest interactions and the relevance of the biological nomad concept

Transects across the margins of rainforests with eucalypt forests at two sites in New South Wales are described. At Girard State Forest along ten transects it was consistently found that pure rainforest occurs where there is no evidence of past burning; and that rainforest tree species appear to be invading and replacing eucalypt forest through a formerly burned ecotone area. A similar pattern was found at Barrington Tops. It is suggested that adaptations shown by species of tall open forests which enable them to regenerate rapidly after burning may have evolved initially in a fire free, prehuman rainforest environment in response to other types of disturbance.     

Without management interventions,endemic wet‐sclerophyll forest is transitioning to rainforest in World Heritage listed K’gari (Fraser Island), Australia

Wet‐sclerophyll forests are unique ecosystems that can transition to dry‐sclerophyll forests or to rainforests. Understanding of the dynamics of these forests for conservation is limited. We evaluated the long‐term succession of wet‐sclerophyll forest on World Heritage listed K'gari (Fraser Island)—the world's largest sand island. We recorded the presence and growth of tree species in three 0.4 hectare plots that had been subjected to selective logging, fire, and cyclone disturbance over 65 years, from 1952 to 2017. Irrespective of disturbance regimes, which varied between plots, rainforest trees recruited at much faster rates than the dominant wet‐sclerophyll forest trees, narrowly endemic species Syncarpia hillii and more common Lophostemon confertus. Syncarpia hillii did not recruit at the plot with the least disturbance and recruited only in low numbers at plots with more prominent disturbance regimes in the ≥10 cm at breast height size. Lophostemon confertus recruited at all plots but in much lower numbers than rainforest trees. Only five L. confertus were detected in the smallest size class (<10 cm diameter) in the 2017 survey. Overall, we find evidence that more pronounced disturbance regimes than those that have occurred over the past 65 years may be required to conserve this wet‐sclerophyll forest, as without intervention, transition to rainforest is a likely trajectory. Fire and other management tools should therefore be explored, in collaboration with Indigenous landowners, to ensure conservation of this wet‐sclerophyll forest.     

Water,land, fire,and forest: Multi‐scale determinants of rainforests in the Australian monsoon tropics

The small rainforest fragments found in savanna landscapes are powerful, yet often overlooked, model systems to understand the controls of these contrasting ecosystems. We analyzed the relative effect of climatic variables on rainforest density at a subcontinental level, and employed high‐resolution, regional‐level analyses to assess the importance of landscape settings and fire activity in determining rainforest density in a frequently burnt Australian savanna landscape. Estimates of rainforest density (ha/km²) across the Northern Territory and Western Australia, derived from preexisting maps, were used to calculate the correlations between rainforest density and climatic variables. A detailed map of the northern Kimberley (Western Australia) rainforests was generated and analyzed to determine the importance of geology and topography in controlling rainforests, and to contrast rainforest density on frequently burnt mainland and nearby islands. In the northwestern Australian, tropics rainforest density was positively correlated with rainfall and moisture index, and negatively correlated with potential evapotranspiration. At a regional scale, rainforests showed preference for complex topographic positions and more fertile geology. Compared with mainland areas, islands had significantly lower fire activity, with no differences between terrain types. They also displayed substantially higher rainforest density, even on level terrain where geomorphological processes do not concentrate nutrients or water. Our multi‐scale approach corroborates previous studies that suggest moist climate, infrequent fires, and geology are important stabilizing factors that allow rainforest fragments to persist in savanna landscapes. These factors need to be incorporated in models to predict the future extent of savannas and rainforests under climate change.     

African rainforests: past,present and future

The rainforests are the great green heart of Africa, and present a unique combination of ecological, climatic and human interactions. In this synthesis paper, we review the past and present state processes of change in African rainforests, and explore the challenges and opportunities for maintaining a viable future for these biomes. We draw in particular on the insights and new analyses emerging from the Theme Issue on ‘African rainforests: past, present and future’ of Philosophical Transactions of the Royal Society B. A combination of features characterize the African rainforest biome, including a history of climate variation; forest expansion and retreat; a long history of human interaction with the biome; a relatively low plant species diversity but large tree biomass; a historically exceptionally high animal biomass that is now being severely hunted down; the dominance of selective logging; small-scale farming and bushmeat hunting as the major forms of direct human pressure; and, in Central Africa, the particular context of mineral- and oil-driven economies that have resulted in unusually low rates of deforestation and agricultural activity. We conclude by discussing how this combination of factors influences the prospects for African forests in the twenty-first century.     

Ecological generalism and resilience of tropical island mammals to logging: A 23 year test

Tropical forest disturbance is a key driver of global biodiversity decline. On continents, the effects of logging are greatest on endemic species, presumably because disturbance is more likely to cover narrower distributions (the “cookie cutter” model). Islands hold disproportionate biodiversity, and are subject to accelerating biotic homogenization, where specialist endemics are lost while generalists persist. We tested responses of tropical island mammals to logging at multiple spatial scales, using a long‐term experimental test in a Pacific archipelago. The most widely distributed ecological generalists did not decline after logging, and we detected no overall changes in relative abundance or species diversity. However, endemics with small ranges did decline in response to logging. The least mobile and most range‐restricted species declined even at the smallest spatial scale, supporting the cookie cutter model for sedentary species, and suggesting that habitat change due to selective logging is contributing to biotic homogenization on islands.     

Factors influencing species selection for littoral rainforest restoration: Do environmental gradients matter?

Summary Littoral rainforest in northern New South Wales, Australia, has been severely reduced in area and is now extremely limited in extent. Factors influencing the floristics, species richness and abundance, and relationship of this coastal rainforest community type to other lowland rainforests are explored. The purpose of the study was to provide ecological information to support (i) the development of management recommendations and assist habitat expansion and restoration planning for a coastal site at Lennox Head, in northern New South Wales, and (ii) the implementation of recovery actions for an endangered ecological community and an endangered tree species. Multivariate analysis techniques were used to classify and ordinate sampled sites relative to environmental variables to provide an explanation for current floristic assemblages. Eight locations at varying distances to the coast, and representing a range of soil types, were chosen to test the influence of selected environmental variables. At the broad scale, the results show that proximity to the coast and altitude were generally correlated and represented the most influential variables; soil depth, topographic position and slope were broadly correlated but markedly less influential; disturbance was a significant but independent influence on floristics; and soil type and aspect had the least influence. The study provided insight into the ecological parameters of a range of species suited to the habitat rehabilitation and restoration project, and identified finer‐scale floristic patterns at the Lennox site that appear to reflect the influence of environmental variables. In that case, areas in closer proximity to the ocean are dominated by several littoral rainforest and disturbance‐related species, and species richness increases relative to distance from the ocean. This highlights the need to be sensitive to landscape variation, and the influence of environmental variables on plant species distributions, and population dynamics and structure, to guide final selection of appropriate plant material for littoral rainforest restoration projects.     

Effects of landscape disturbance on mosquito community composition in tropical Australia

Emerging infectious diseases are considered to be a growing threat to human and wildlife health. Such diseases might be facilitated by anthropogenic land-use changes that cause novel juxtapositions of different habitats and species and result in new interchanges of vectors, diseases, and hosts. To search for such effects in tropical Australia, we sampled mosquito populations across anthropogenic disturbance gradients of grassland, artificial rainforest edge, and rainforest interior. From >15,000 captured mosquitoes, we identified 26 species and eight genera. Surprisingly, there was no significant difference in community composition or species richness between forest edges and grasslands, but both differed significantly from rainforest interiors. Mosquito species richness was elevated in grasslands relative to the rainforest habitats. Seven species were unique to grasslands and edges, with another 13 found across all habitats. Among the three most abundant species, Culex annulirostris occurred in all habitat types, whereas Verrallina lineata and Cx. pullus were more abundant in forest interiors. Our findings suggest that the creation of anthropogenic grasslands adjacent to rainforests may increase the susceptibility of species in both habitats to transmission of novel diseases via observable changes and mixing of the vector community on rainforest edges.     

Kuku—Yalanji Rainforest Aboriginal People and Carbohydrate Resource Management in the Wet Tropics of Queensland, Australia

Carbohydrate food sources have emerged as a critical factor limiting occupation of rainforests by hunter—gatherer peoples globally. In the wet tropics bioregion of northeastern Australia, Kuku–Yalanji aboriginal people occupied the rainforests through a hunter–gatherer subsistence economy prior to European occupation. Collaborative environmental research between a researcher at the James Cook University and Kuku–Yalanji people has established that their fire management protected carbohydrate resources in the fire-sensitive rainforests and their margins, and ensured ongoing access to the critical dry season carbohydrate resource, Cycas media, growing in patches of fire-prone open forest on each clan estate. Carbohydrate resources in the wet season were obtained predominantly from seeds of rainforest tree nuts, a high proportion of which are wet tropics endemic species. Several of the genera utilized by aboriginal people in the wet tropics bioregion also occur in the rainforests of eastern Cape York Peninsula, where they were not utilized as foods. It is hypothesized that use of rainforest seeds for carbohydrate is a cultural adaptation that occurred in the wet tropics bioregion, stimulated by the unique availability of the substantial number of large-seeded rainforest trees that are wet tropics endemics. The implications of these data for concepts about the impact of aboriginal fires on Australian rainforests are considered. Aboriginal fires imposed a fine patterning on the vegetation at the local scale, with little effect on the vegetation at the regional scale, which is determined by environmental factors.     

Disturbance and forest dynamics along a transect from Andean rain forest to Patagonian shrubland

Abstract. At ca. 40° S in northern Patagonia, Andean rain forests are replaced eastwards by woodlands and shrublands and eventually by steppe. Along this gradient we examined stand dynamics by analyzing tree population age structures and tree growth patterns. We also examined spatial and temporal characteristics of disturbance regimes by dating disturbances and mapping stands of differing disturbance history. From west to east, the ecological importance of earthquake-related disturbance decreases, whereas that of fire, logging, and livestock increases. Abrupt changes in rates of tree growth correspond with earthquakes in 1837, 1939 and 1960. In the mesic western forests earthquakes can result in massive new tree establishment on landslide-affected sites and increased rates of treefall. Fire, however, is the more pervasive disturbance over most of the gradient and creates extensive even-aged patches dominated by the regionally dominant trees, Nothofagus and Austrocedrus. Although some lightning-ignited and aboriginal-set fires occurred in these forests prior to European settlement, much of the present forest structure may be attributed to the massive burning associated with European settlement of this area near the turn of the present century. In contrast to the settlement-related increase in fire frequency in the western forested district, at the woodland/steppe ecotone the demise of the native American population resulted in a decrease in fire frequency. Heavy browsing and grazing following fire can seriously impede post-fire tree regeneration. These preliminary results document the important influences of varying disturbance regimes along a major environmental gradient in creating landscape-scale vegetation patterns.     

Exotic vine invasions following cyclone disturbance in Australian Wet Tropics rainforests: A review

The Australian Wet Tropics region extends for almost 900 000 ha along the coastline of north‐east Queensland. The rainforests in this region have a rich and unique biodiversity and are World Heritage listed by UNESCO. Disturbance from tropical cyclones is a significant driver of the rainforest dynamics in this area, and when frequent or intense can facilitate the recruitment and expansion of exotic invasive species. Exotic vines are of particular concern for forest conservation as they can be highly competitive with native vegetation and may prevent forest regeneration. This literature review found evidence that fragmented forests, which are very common in the Australian Wet Tropics, are vulnerable to post‐cyclone vine invasion. In particular, although the diversity and abundance of herbaceous vines tend to decline as the canopy closes 2 years post‐cyclone disturbance, woody exotic vines and scramblers may persist for much longer or even increase in numbers. Since forest recovery in these systems is influenced by the severity and recurrence of disturbance, an increase in cyclone intensity under climate change may cause rapid changes in rainforest structure, composition and diversity, and increase exotic vine invasion. Post‐cyclone management of vines appears to require direct intervention, with manual cutting being currently the most effective method. However, there are a number of difficulties to its wide implementation in Australia, and further study on options for control is needed. Abstract in Spanish is available with online material.     

Functional trait differences influence neighbourhood interactions in a hyperdiverse Amazonian forest

As distinct community assembly processes can produce similar community patterns, assessing the ecological mechanisms promoting coexistence in hyperdiverse rainforests remains a considerable challenge. We use spatially explicit neighbourhood models of tree growth to quantify how functional trait and phylogenetic similarities predict variation in growth and crowding effects for the 315 most abundant tree species in a 25‐ha lowland rainforest plot in Ecuador. We find that functional trait differences reflect variation in (1) species maximum potential growth, (2) the intensity of interspecific interactions for some species, and (3) species sensitivity to neighbours. We find that neighbours influenced tree growth in 28% of the 315 focal tree species. Neighbourhood effects are not detected in the remaining 72%, which may reflect the low statistical power to model rare taxa and/or species insensitivity to neighbours. Our results highlight the spectrum of ways in which functional trait differences can shape community dynamics in highly diverse rainforests.     

Forest fragmentation and selective logging have inconsistent effects on multiple animal-mediated ecosystem processes in a tropical forest

Forest fragmentation and selective logging are two main drivers of global environmental change and modify biodiversity and environmental conditions in many tropical forests. The consequences of these changes for the functioning of tropical forest ecosystems have rarely been explored in a comprehensive approach. In a Kenyan rainforest, we studied six animal-mediated ecosystem processes and recorded species richness and community composition of all animal taxa involved in these processes. We used linear models and a formal meta-analysis to test whether forest fragmentation and selective logging affected ecosystem processes and biodiversity and used structural equation models to disentangle direct from biodiversity-related indirect effects of human disturbance on multiple ecosystem processes. Fragmentation increased decomposition and reduced antbird predation, while selective logging consistently increased pollination, seed dispersal and army-ant raiding. Fragmentation modified species richness or community composition of five taxa, whereas selective logging did not affect any component of biodiversity. Changes in the abundance of functionally important species were related to lower predation by antbirds and higher decomposition rates in small forest fragments. The positive effects of selective logging on bee pollination, bird seed dispersal and army-ant raiding were direct, i.e. not related to changes in biodiversity, and were probably due to behavioural changes of these highly mobile animal taxa. We conclude that animal-mediated ecosystem processes respond in distinct ways to different types of human disturbance in Kakamega Forest. Our findings suggest that forest fragmentation affects ecosystem processes indirectly by changes in biodiversity, whereas selective logging influences processes directly by modifying local environmental conditions and resource distributions. The positive to neutral effects of selective logging on ecosystem processes show that the functionality of tropical forests can be maintained in moderately disturbed forest fragments. Conservation concepts for tropical forests should thus include not only remaining pristine forests but also functionally viable forest remnants.     

Dirt roads and fire breaks produce no edge effects on litter-dwelling arthropods in a tropical dry-forest: a case study

Edge effects threaten organisms and ecological processes in habitat remnants, but they have been poorly studied in non-humid forests such as cerradão, a tropical dry forest sometimes derived from fire-suppressed savanna in Brazil. The diverse ecosystem functions performed by arthropods may be disrupted by edge effects, and there is pressing need for more studies on this subject. We sampled fragments of cerradão facing either a road or fire breaks, assessing edge effects in: beta diversity and community composition of epigaeic (litter-dwelling) arthropod orders, ant species, and ant functional groups; ant species richness and diversity; leaf litter depth; and colony residence time of a predatory ground-dwelling ant, Odontomachus chelifer (Ponerinae). None of the variables measured differed between edge and interior of the sites sampled. Dry forests have high micro-climatic variations caused by discontinuities in the canopy cover and, as such, changes in abiotic variables in cerradão edges might not be as clear as those observed in tropical rainforests. Our study demonstrates that edge effects may not be so prevalent in cerradão facing roads or fire breaks, which possibly increases the chances of survival of a higher fraction of the original arthropod fauna compared to rainforest fragments.     

Vertebrate herbivores are the main cause of seedling mortality in a logged African rainforest—implications for forest restoration

High seedling mortality can limit tropical forest regeneration after disturbance, such as selective logging. However, causes of seedling mortality are often poorly understood although this information is critical for designing appropriate restoration methods. We studied seedling mortality in a rainforest in Uganda where natural recovery has failed after selective logging carried out 40 years earlier and the sites are dominated by herbaceous vegetation. We established an experiment where seeds of 12 indigenous tree species were sown into different‐sized logging gaps in order to capture factors that cause early seedling mortality. We examined whether seedling mortality was influenced by vegetation cover (VC), vertebrate herbivores (VHs), gap size, or forest compartment and recorded causes of mortality. We found that seedling mortality was in general high but showed high tree species‐specific variation (ranging from 19 to 92% six months after emergence). VHs, particularly rodents, were the most important cause of mortality. Rotting caused mortality particularly in smaller gaps, but elephant trampling, drying, being washed away by rain and falling debris were only minor mortality causes. Dense VC was not a considerable barrier to seedling survival, but by providing shelter for rodents, it indirectly increased seedling herbivory. Our results show that high seedling mortality on logged sites can limit forest regeneration and rodents in particular can be a significant factor causing high seedling mortality.     

Stand structure of the emergent conifer Araucaria laubenfelsii) in maquis and rainforest,Mont Do,New Caledonia

Abstract Despite its small size, New Caledonia has a flora which includes 43 endemic species of conifer. This study examines the stand structure of the New Caledonian conifer, Araucaria laubenfelsii Corbasson, a species which occurs on ukramafic soils as an emergent tree in rainforest and in an unusual structural association with maquis vegetation. Fire and cyclone blow-down are the primary disturbances in the maquis, but fire is infrequent in the rainforests which is evident from the low proportion of fire scarred trees. Preliminary results show abundant seedlings and saplings of A. laubenfelsii both in maquis and forest. Size class distributions of individuals suggest that the species is continuously regenerating in the maquis and immature forests. Variability in the stand structure in maquis communities reflects the probable patchy nature of disturbance from small-scale fires and blow-down from tropical cyclones. In mature forests, Nothofagus codonandra (Baillon) Steenis is the dominant canopy species and ‘other tree species’ are continuously regenerating, while the size class distributions and basal area of A. laubenfelsii suggest that there is, at present, limited regeneration of this species. Tree ring counts indicate that individuals in forest areas grow at a slower rate than those in maquis, but attain greater age, probably as a result of greater protection from fire.     

Impacts of Intensive Logging on the Trophic Organisation of Ant Communities in a Biodiversity Hotspot

Trophic organisation defines the flow of energy through ecosystems and is a key component of community structure. Widespread and intensifying anthropogenic disturbance threatens to disrupt trophic organisation by altering species composition and relative abundances and by driving shifts in the trophic ecology of species that persist in disturbed ecosystems. We examined how intensive disturbance caused by selective logging affects trophic organisation in the biodiversity hotspot of Sabah, Borneo. Using stable nitrogen isotopes, we quantified the positions in the food web of 159 leaf-litter ant species in unlogged and logged rainforest and tested four predictions: (i) there is a negative relationship between the trophic position of a species in unlogged forest and its change in abundance following logging, (ii) the trophic positions of species are altered by logging, (iii) disturbance alters the frequency distribution of trophic positions within the ant assemblage, and (iv) disturbance reduces food chain length. We found that ant abundance was 30% lower in logged forest than in unlogged forest but changes in abundance of individual species were not related to trophic position, providing no support for prediction (i). However, trophic positions of individual species were significantly higher in logged forest, supporting prediction (ii). Consequently, the frequency distribution of trophic positions differed significantly between unlogged and logged forest, supporting prediction (iii), and food chains were 0.2 trophic levels longer in logged forest, the opposite of prediction (iv). Our results demonstrate that disturbance can alter trophic organisation even without trophically-biased changes in community composition. Nonetheless, the absence of any reduction in food chain length in logged forest suggests that species-rich arthropod food webs do not experience trophic downgrading or a related collapse in trophic organisation despite the disturbance caused by logging. These food webs appear able to bend without breaking in the face of some forms of anthropogenic disturbance.     

Initial response of understorey vegetation to fire severity and salvage‐logging in the southern boreal forest of Québec

Abstract. In this study we compared the effects of fire on understorey vegetation in the Québec southern boreal forest with effects of salvage‐logging (clear‐cutting after fire). All 61 400‐m² sampling sites were controlled for overstorey composition (Deciduous, Mixed and Coniferous) and disturbance type, which consisted of three fire impact severity (FIS) classes (Light, Moderate and Extreme) and two harvesting techniques (Stem‐only and Whole‐tree Harvesting). Percent‐cover data of vegetation and post‐disturbance environmental characteristics were recorded in the field during the first two years after fire as well as soil texture. Ordination of fire alone demonstrated that, on Coniferous sites, fire initiates a succession whereby the understorey Coniferous sites approaches that of Deciduous‐Mixed sites, due to the release of the understorey from Sphagnum spp. dominance, this pattern being a function of FIS. On Deciduous‐Mixed stands, increased FIS resulted in a transition from herb to shrub dominance. Ordination of all five disturbance types showed that the impact of salvage‐logging on understorey composition was within the range of fire, but marginalized to the extreme end of the FIS spectrum. Variance partitioning demonstrated that overstorey and soil texture were the most important explanatory variables of fire alone, while disturbance type explained the largest independent fraction of understorey variation when salvage‐logging was introduced. Salvage‐logging also results in significant reductions in understorey abundance, richness and diversity, while indicator species analysis suggests that it favours mesoxerophytic to xeric species. Results are interpreted in light of shade‐tolerance dynamics, forest floor disturbance and soil moisture regimes. Implications for sustainable forest management are discussed.     

The distribution of vascular epiphytes over gradients of light and humidity in north‐east Australian rainforest

Microclimatic conditions have a strong influence on the distribution of vascular epiphytes, among which orchids often occur in sunnier and more drought‐prone situations than ferns. However, very few studies have looked at the distribution of ferns and orchids in Australian tropical rainforests. By using transmitted light measurements at the locations of individual epiphytes and vapour pressure deficit from the canopy and base of host trees, we were able to determine the patterns of light and humidity in the rainforest environment, and the responses of ferns and orchids to variation in the physical environments. We surveyed five sites, ranging from 800 to 1180 m in elevation in the lower montane rainforests of north‐east Australia. Data loggers recorded the vapour pressure deficit (VPD) at the forest floor and canopy of each site. Light was correlated with height within the host tree and VPD differed significantly over position in the host tree and elevation. There was a strong partitioning of taxonomic groups over the light and VPD gradients. Orchids occurred in environments that had higher mean light levels and mean daily maximum VPD (27% and 0.43 kPa, respectively) than ferns (21% and 0.28 kPa). There was also strong microclimatic partitioning of species within taxonomic groups, suggesting that microclimatic factors play an important role in the realized niche spaces of epiphytes within the tropical Australian rainforest. Thus, the tested ecological generalizations made on tropical rainforest epiphytes apply in Australia.     

A pantropical analysis of the impacts of forest degradation and conversion on local temperature

Temperature is a core component of a species' fundamental niche. At the fine scale over which most organisms experience climate (mm to ha), temperature depends upon the amount of radiation reaching the Earth's surface, which is principally governed by vegetation. Tropical regions have undergone widespread and extreme changes to vegetation, particularly through the degradation and conversion of rainforests. As most terrestrial biodiversity is in the tropics, and many of these species possess narrow thermal limits, it is important to identify local thermal impacts of rainforest degradation and conversion. We collected pantropical, site‐level (<1 ha) temperature data from the literature to quantify impacts of land‐use change on local temperatures, and to examine whether this relationship differed aboveground relative to belowground and between wet and dry seasons. We found that local temperature in our sample sites was higher than primary forest in all human‐impacted land‐use types (N = 113,894 daytime temperature measurements from 25 studies). Warming was pronounced following conversion of forest to agricultural land (minimum +1.6°C, maximum +13.6°C), but minimal and nonsignificant when compared to forest degradation (e.g., by selective logging; minimum +1°C, maximum +1.1°C). The effect was buffered belowground (minimum buffering 0°C, maximum buffering 11.4°C), whereas seasonality had minimal impact (maximum buffering 1.9°C). We conclude that forest‐dependent species that persist following conversion of rainforest have experienced substantial local warming. Deforestation pushes these species closer to their thermal limits, making it more likely that compounding effects of future perturbations, such as severe droughts and global warming, will exceed species' tolerances. By contrast, degraded forests and belowground habitats may provide important refugia for thermally restricted species in landscapes dominated by agricultural land.     

Climate change and tropical biodiversity: a new focus

Considerable efforts are focused on the consequences of climate change for tropical rainforests. However, potentially the greatest threats to tropical biodiversity (synergistic interactions between climatic changes and human land use) remain understudied. Key concerns are that aridification could increase the accessibility of previously non-arable or remote lands, elevate fire impacts and exacerbate ecological effects of habitat disturbance. The growing climatic change literature often fails to appreciate that, in coming decades, climate-land use interactions might be at least as important as abiotic changes per se for the fate of tropical biodiversity. In this review, we argue that protected area expansion along key ecological gradients, regulation of human-lit fires, strategic forest-carbon financing and re-evaluations of agricultural and biofuel subsidies could ameliorate some of these synergistic threats.