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The rapid disruption of tropical forests probably imperils global biodiversity more than any other contemporary phenomenon (1-3). With deforestation advancing quickly, protected areas are increasingly becoming final refuges for threatened species and natural ecosystem processes. However, many protected areas in the tropics are themselves vulnerable to human encroachment and other environmental stresses (4-9). As pressures mount, it is vital to know whether existing reserves can sustain their biodiversity. A critical constraint in addressing this question has been that data describing a broad array of biodiversity groups have been unavailable for a sufficiently large and representative sample of reserves. Here we present a uniquely comprehensive data set on changes over the past 20 to 30 years in 31 functional groups of species and 21 potential drivers of environmental change, for 60 protected areas stratified across the world's major tropical regions. Our analysis reveals great variation in reserve 'health': about half of all reserves have been effective or performed passably, but the rest are experiencing an erosion of biodiversity that is often alarmingly widespread taxonomically and functionally. Habitat disruption, hunting and forest-product exploitation were the strongest predictors of declining reserve health. Crucially, environmental changes immediately outside reserves seemed nearly as important as those inside in determining their ecological fate, with changes inside reserves strongly-mirroring those occurring around them. These findings suggest that tropical protected areas are often intimately linked ecologically to their surrounding habitats, and that a failure to stem broad-scale loss and degradation of such habitats could sharply increase the likelihood of serious biodiversity declines., Tropical forests are the biologically richest ecosystems on Earth (1-3). Growing concerns about the impacts of anthropogenic pressures on tropical biodiversity and natural ecosystem services have led to increases in [...]

The main theories explaining the biological diversity of rain forests often confer a limited understanding of the contribution of interspecific interactions to the observed patterns. We show how two-species mutualisms can affect much larger segments of the invertebrate community in tropical rain forests. Aechmea mertensii (Bromeliaceae) is both a phytotelm (plant-held water) and an ant-garden epiphyte. We studied the influence of its associated ant species (Pachycondyla goeldii and Camponotus femoratus) on the physical characteristics of the plants, and, subsequently, on the diversity of the invertebrate communities that inhabit their tanks. As dispersal agents for the bromeliads, P. goeldii and C. femoratus influence the shape and size of the bromeliad by determining the location of the seedling, from exposed to partially shaded areas. By coexisting on a local scale, the two ant species generate a gradient of habitat conditions in terms of available resources (space and food) for aquatic invertebrates, the diversity of the invertebrate communities increasing with greater volumes of water and fine detritus. Two-species mutualisms are widespread in nature, but their influence on the diversity of entire communities remains largely unexplored. Because macroinvertebrates constitute an important part of animal production in all ecosystem types, further investigations should address the functional implications of such indirect effects. Key words: Aechmea mertensii; ant-gardens; biodiversity; brorneliads; Camponotus femoratus; Crematogaster levior; macroinvertebrates; mutualism; Pachycondyla goeldii; phytotelmata; secondary forest, Sinnamary, French Guiana; species interactions.

Different life history strategies among tropical rain forest species are generally related to inherent trade-offs in leaf and crown traits, with early-successional species having traits that facilitate high productivity but a relatively wasteful use of resources and shade-tolerant later-successional species exhibiting the opposite strategy. But the degree to which these trait differences contribute to short-and long-term carbon gain of different species that coexist in natural forest has not been quantitatively scaled. We applied a canopy model in combination with measurements of canopy structure, mass distribution, and leaf photosynthesis to determine whole-plant daily photosynthesis ([P.sub.pl]) of individuals of three short-lived pioneers (SLP), four later-successional species, and three lianas growing together in a 0.5-, 2-, and 3-yr-old secondary tropical forest stand. Whole-plant daffy photosynthesis per unit leaf mass ([P.sub.lfm]) and aboveground mass ([P.sub.m]) were assumed to indicate daily returns on investment at the leaf and crown level. By integrating these calculations with measured leaf longevities, we determined the lifetime carbon gain per unit leaf mass. Vegetation height and leaf area index increased with stand age. Two of the SLPs, Trema and Ochroma, increasingly dominated the top of the vegetation. In the 0.5-yr-old stand, these species also had the highest [P.sub.m] and [P.sub.lfm] values. Whole-plant daily photosynthesis per unit leaf mass tended to decline with stand age but much more strongly so in the later-successional species than in the SLP. Leaf longevity was not significantly correlated with individual leaf traits (e.g., specific leaf area or leaf N content) but was strongly and negatively correlated with [P.sub.lfm] in the youngest stand. Later-successional species had considerably greater leaf longevities than SLP. Lifetime carbon gain per unit leaf mass, however, was relatively similar between the different species. Thus due to the strong negative correlation that exists between daily leaf productivity ([P.sub.lfm]) and longevity, short-lived pioneers and later-successional species achieve similar lifetime carbon gain per unit leaf mass in natural secondary forest. This could help explain why the slower-growing later-successional species are able to persist during the first years of succession. Key words: Bolivian Amazon; canopy model; leaf functional traits, leaf longevity; lianas; light interception; photosynthesis; pioneers: secondary succession; specific leaf area; tropical rain forest.

Neotropical rainforests have a very poor fossil record, making hypotheses concerning their origins difficult to evaluate. Nevertheless, some of their most important characteristics can be preserved in the fossil record: high plant diversity, dominance by a distinctive combination of angiosperm families, a preponderance of plant species with large, smooth-margined leaves, and evidence for a high diversity of herbivorous insects. Here, we report on an [approximately equal to]58-my-old flora from the Cerrejon Formation of Colombia (paleolatitude [approximately equal to]5 [degrees]N) that is the earliest megafossil record of Neotropical rainforest. The flora has abundant, diverse palms and legumes and similar family composition to extant Neotropical rainforest. Three-quarters of the leaf types are large and entire-margined, indicating rainfall >2,500 mm/year and mean annual temperature >25 [degrees]C. Despite modern family composition and tropical paleoclimate, the diversity of fossil pollen and leaf samples is 60-80% that of comparable samples from extant and Quaternary Neotropical rainforest from similar climates. Insect feeding damage on Cerrejon fossil leaves, representing primary consumers, is abundant, but also of low diversity, and overwhelmingly made by generalist feeders rather than specialized herbivores. Cerrejon megafossils provide strong evidence that the same Neotropical rainforest families have characterized the biome since the Paleocene, maintaining their importance through climatic phases warmer and cooler than present. The low diversity of both plants and herbivorous insects in this Paleocene Neotropical rainforest may reflect an early stage in the diversification of the lineages that inhabit this biome, and/or a long recovery period from the terminal Cretaceous extinction. diversity | stability | paleoclimate | paleobotany | Fabaceae www.pnas.org/cgi/doi/10.1073/pnas.0905130106

We obtained spatially extensive canopy height measurements using airborne remote sensing to characterize the structure and dynamics of a tropical rain forest landscape. Light detection and ranging (LiDAR) is a remote-sensing technology that acquires measurements of canopy height and ground elevation. By recording the return time of laser pulses emitted by aircraft-mounted sensors, LiDAR systems quantify the structure and geometry of individual trees and canopy height and enable estimation of the vertical and horizontal distribution of biomass using millions of accurate height measurements. This data set contains 127 849 839 records from 128 square kilometers of tropical wet forest in the Atlantic lowlands of Costa Rica (mean sampling density is 1.99 observations/[m.sup.2]). The study area includes all 16 square kilometers of mixed-land-use forest at the La Selva Biological Station and the lower flanks of Braulio Carrillo National Park. It contains a mosaic of historical and contemporary land use that is representative of contemporary tropical forest landscapes. Field studies demonstrated that LiDAR measurements were precise and accurate throughout the topographic and structural conditions at the site. Each record includes: easting and northing mapped coordinates (UTM Zone 16 North), height above ground (m), interpolated ground elevation (m), and six remote-sensing descriptors (point classification, the return number, the number of returns for the given pulse, intensity, scan angle, and the time of emission of the laser pulse). The data can be applied to a wide range of questions in basic and applied science, and are a valuable resource from a well-studied tropical rain forest for teaching and education. They also provide a quantitative baseline against which future conditions can be assessed. Key words: biomass,' carbon; Costa Rica; Jbrest structure; landscape; La Selva Biological Station; LiDAR; light detection and ranging; Neotropics; remote sensing; sustainability.

Forest fragmentation may have positive or negative effects on tropical tree populations. Our earlier study of an endemic African tree, Leptonychia usambarensis (Sterculiaceae), in the East Usambara Mountains of Tanzania, found poorer recruitment of seedlings and juveniles in small fragments compared to continuous forest, and concomitant reduction of seed-dispersal agents and seed dispersal. However, the possibility that other biotic or abiotic consequences of the fragmentation process contribute to diminished recruitment in fragments was left open. Here we test whether excessive seed predation, diminished fecundity, low seed quality, or adverse abiotic effects acted independently or in concert with reduced seed dispersal to limit seedling and juvenile recruitment in fragments. Extended observations of disperser activity, a seed placement experiment, seed predator censuses, and reciprocal seedling transplants from forest and fragment sources failed to support the alternative hypotheses for poorer seedling and juvenile recruitment in fragments, leaving reduced seed dispersal as the most plausible mechanism. Poorer recruitment of this species in forest fragments, where high edge-to-area ratios admit more light than in continuous forest, is particularly striking because the tree is an early successional species that might be expected to thrive in disturbed microhabitats. Key words: Africa; doves; Eastern Are Mountains; edge effects; frugivory; habitat fragmentation; inbreeding; mutualism; rodents; seed dispersal; seed predation; tropical forest.

Many plants interact with groups of mutualist pollinators and seed dispersers. A key issue for both basic ecology and conservation is whether the different species within these guilds of mutualist animals are functionally equivalent. Comparing the relative effects of sympatric mutualists is important for understanding the evolution of multispecies mutualisms and for predicting mutualism stability in the face of anthropogenic change. However, empirical comparisons of the population-level impacts of mutualist animals on their host plant are rare, particularly for seed dispersal mutualisms in species-rich ecosystems. We compared the influence of three seed-dispersing tropical mammals, lar gibbons (Hylobates lar), sambar deer (Rusa unicolor), and red muntjac deer (Muntiacus muntjak), on the demography of a shared host tree in Thailand, Choerospondias axillaris (Anacardiaceae). Sambar and muntjac dispersed far more C. axillaris seeds than did gibbons. While sambar deposited many seeds under female tree canopies, muntjac were the only disperser to move seeds to open microhabitats, where C. axillaris seed germination, seedling survival, and initial growth are enhanced. Using stage-based population models, we assessed how disperser-specific seed dispersal, variation in the frequency of canopy gap formation, and their interaction influenced the potential population growth of C. axillaris. Large differences in dispersal quantity and small differences in dispersal quality among sambar and gibbons resulted in similar and negligible impacts on the tree's population dynamics. Muntjac, by taking some of the seeds to open microhabitats, are projected to have a greater positive impact on C. axillaris demography than either sambar or gibbons. Model comparisons of population-level species impacts may allow us to predict which ecological interactions are at risk from loss of critical species. Key words: biodiversity; Choerospondias axillaris; demography; dispersal effectiveness; gap dynamics; gibbons; muntjac deer; mutualism; redundancy; sambar deer; seed dispersal; tropical seasonal forests, Thailand.

There has been considerable recent interest in how human-induced species loss affects community and ecosystem properties. These effects are particularly apparent when a commercially valuable species is harvested from an ecosystem, such as occurs through single-tree harvesting or selective logging of desired timber species in natural forests. In New Zealand mixed-species rain forests, single-tree harvesting of the emergent gymnosperm Dacrydium cupressinum, or rimu, has been widespread. This harvesting has been contentious in part because of possible ecological impacts of Dacrydium removal on the remainder of the forest, but many of these effects remain unexplored. We identified an area where an unintended 40-year 'removal experiment' had been set up that involved selective extraction of individual Dacrydium trees. We measured aboveground and belowground variables at set distances from both individual live trees and stumps of trees harvested 40 years ago. Live trees had effects both above and below ground by affecting diversity and cover of several components of the vegetation (usually negatively), promoting soil C sequestration, enhancing ratios of soil C:P and N:P, and affecting community structure of soil microflora. These effects extended to 8 m from the tree base and were likely caused by poor-quality litter and humus produced by the trees. Measurements for the stumps revealed strong legacy effects of prior presence of trees on some properties (e.g., cover by understory herbs and ferns, soil C sequestration, soil C:P and N:P ratios), but not others (e.g., soil fungal biomass, soil N concentration). These results suggest that the legacy of prior presence of Dacrydium may remain for several decades or centuries, and certainly well over 40 years. They also demonstrate that, while large Dacrydium individuals (and their removal) may have important effects in their immediate proximity, within a forest, these effects should only be important in localized patches containing high densities of large trees. Finally, this study emphasizes that deliberate extraction of a particular tree species from a forest can exert influences both above and below ground if the removed species has a different functional role than that of the other plant species present. Key words: Dacrydium cupressinum; microbial community; New Zealand; removal experiment; rimu; selective logging; single-tree harvesting; species effects.

Seed dispersal and seedling recruitment (the transition of seeds to seedlings) set the spatiotemporal distribution of new individuals in plant communities. Many terrestrial rain forest mammals consume post-dispersal seeds and seedlings, often inflicting density-dependent mortality. In part because of density-dependent mortality, diversity often increases during seedling recruitment, making it a critical stage for species coexistence. We determined how mammalian predators, adult tree abundance, and seed mass interact to affect seedling recruitment in a western Amazonian rain forest. We used exclosures that were selectively permeable to three size classes of mammals: mice and spiny rats (weighing Key words: density dependence; maintenance of biodiversity; Manu National Park, Peru; seed dispersal; seed predation, seedling recruitment; Tayassu peccari; tropical rain forest.

Factors affecting survival and recruitment of 3531 individually mapped seedlings of Myristicaceae were examined over three years in a highly diverse neotropical rain forest, at spatial scales of 1-9 m and 25 ha. We found convincing evidence of a community compensatory trend (CCT) in seedling survival (i.e., more abundant species had higher seedling mortality at the 25-ha scale), which suggests that density-dependent mortality may contribute to the spatial dynamics of seedling recruitment. Unlike previous studies, we demonstrate that the CCT was not caused by differences in microhabitat preferences or life history strategy among the study species. In local neighborhood analyses, the spatial autocorrelation of seedling survival was important at small spatial scales (1-5 m) but decayed rapidly with increasing distance. Relative seedling height had the greatest effect on seedling survival. Conspecific seedling density had a more negative effect on survival than heterospecific seedling density and was stronger and extended farther in rare species than in common species. Taken together, the CCT and neighborhood analyses suggest that seedling mortality is coupled more strongly to the landscape-scale abundance of conspecific large trees in common species and the local density of conspecific seedlings in rare species. We conclude that negative density dependence could promote species coexistence in this rain forest community but that the scale dependence of interactions differs between rare and common species. Key words: autologistic regression: community compensatory trend (CCT); Ecuador; Myristicaceae; seedling; spatial autocorrelation; species coexistence; tropical forest; Yasuni.

We investigated the relationship between habitat association and physiological performance in four congeneric species pairs exhibiting contrasting distributions between seasonally flooded and terra firme habitats in lowland tropical rain forests of French Guiana, including Virola and Iryanthera (Myristicaceae), Symphonia (Clusiaceae), and Eperua (Caesalpiniaceae). We analyzed 10-year data sets of mapped and measured saplings (stems [greater than or equal to ]150 cm in height and < 10 cm diameter at breast height [dbh]) and trees (stems [greater than or equal to] 10 cm dbh) across 37.5 ha of permanent plots covering a 300-ha zone, within which seasonally flooded areas (where the water table never descends below 1 m) have been mapped. Additionally, we tested the response of growth, survival, and leaf functional traits of these species to drought and flood stress in a controlled experiment. We tested for habitat preference using a modification of the torus translation method. Strong contrasting associations of the species pairs of Iryanthera, Virola, and Symphonia were observed at the sapling stage, and these associations strengthened for the tree stage. Neither species of Eperua was significantly associated with flooded habitats at the sapling stage, but E. falcata was significantly and positively associated with flooded forests at the tree stage, and trees of E. grandiflora were found almost exclusively in nonflooded habitats. Differential performance provided limited explanatory support for the observed habitat associations, with only congeners of Iryanthera exhibiting divergent sapling survival and tree growth. Seedlings of species associated with flooded forest tended to have higher photosynthetic capacity than their congeners at field capacity. In addition, they tended to have the largest reductions in leaf gas exchange and growth rate in response to experimental drought stress and the least reductions in response to experimental inundation. The corroboration of habitat association with differences in functional traits and, to a lesser extent, measures of performance provides an explanation for the regional coexistence of these species pairs. We suggest that specialization to seasonally flooded habitats may explain patterns of adaptive radiation in many tropical tree genera and thereby provide a substantial contribution to regional tree diversity. Key words: drought tolerance; French Guiana; photosynthetic capacity; phylogenetically independent contrast; relative growth rate; seasonally flooded forest; specific leaf area; torus translation method; tropical forest.

Abstract. It has been hypothesized that tropical trees partition forest light environments through a life history trade-off between juvenile growth and survival; however, the generality of this trade-off across life stages and functional groups has been questioned. We quantified trade-offs between growth and survival for trees and lianas on Barro Colorado Island (BCI), Panama using first-year seedlings of 22 liana and 31 tree species and saplings (10 mm < dbh < 39 mm) of 30 tree species. Lianas showed trade-offs similar to those of trees, with both groups exhibiting broadly overlapping ranges in survival and relative growth rates as seedlings. Life history strategies at the seedling stage were highly correlated with those at the sapling stage among tree species, with all species showing an increase in survival with size. Only one of 30 tree species demonstrated a statistically significant ontogenetic shift, having a relatively lower survival rate at the sapling stage than expected. Our results indicate that similar life history trade-offs apply across two functional groups (lianas and trees), and that life history strategies are largely conserved across seedling and sapling life-stages for most tropical tree species. Key words: growth; liana; life history; ontogenetic shift; sapling; seedling; shade tolerance; survival; trade-offs; tropical forest.

Terrestrial biosphere--atmosphere C[O.sub.2] exchange is dominated by tropical forests, so understanding how nutrient availability affects carbon (C) decomposition in these ecosystems is central to predicting the global C cycle's response to environmental change. In tropical rain forests, phosphorus (P) limitation of primary production and decomposition is believed to be widespread, but direct evidence is rare. We assessed the effects of nitrogen (N) and P fertilization on litter-layer organic matter decomposition in two neighboring tropical rain forests in southwest Costa Rica that are similar in most ways, but that differ in soil P availability. The sites contain 100-200 tree species per hectare and between species foliar nutrient content is variable. To control for this heterogeneity, we decomposed leaves collected from a widespread neotropical species, Brosimum utile. Mass loss during decomposition was rapid in both forests, with B. utile eaves losing >80% of their initial mass in Key words: Brosimum utile; decomposition; dissolved organic carbon (DOC); dissolved organic matter (DOM); fertilization; leaching; nitrogen; nutrient limitation; phosphorus; tropical rain forest.

The hydraulic resistance of the leaf ([R.sub.1]) is a major bottleneck in the whole plant water transport pathway and may thus be linked with the enormous variation in leaf structure and function among tropical rain forest trees. A previous study found that [R.sub.1] varied by an order of magnitude across 10 tree species of Panamanian tropical lowland rain forest. Here, correlations were tested between [R.sub.1] and 24 traits relating to leaf venation and mesophyll structure, and to gross leaf form. Across species, [R.sub.1] was related to both venation architecture and mesophyll structure. [R.sub.1] was positively related to the theoretical axial resistivity of the midrib, determined from xylem conduit numbers and dimensions, and [R.sub.1] was negatively related to venation density in nine of 10 species. [R.sub.1] was also negatively related to both palisade mesophyll thickness and to the ratio of palisade to spongy mesophyll. By contrast, numerous leaf traits were independent of [R.sub.1], including area, shape, thickness, and density, demonstrating that leaves can be diverse in gross structure without intrinsic trade-offs in hydraulic capacity. Variation in both [R.sub.1]-linked and [R.sub.1]-independent traits related strongly to regeneration irradiance, indicating the potential importance of both types of traits in establishment ecology. Key words: Barro Colorado Island Nature Monument (BCI); biological networks; high pressure flow meter (HPFM); leaf hydraulics; Panama; rain forest trees; shade tolerance; vasculature.

Few studies have directly assessed how rapidly functionally important insect communities recover following rain forest loss and fragmentation. In 1986, B. Klein compared the dung and carrion beetle assemblages of clearcuts, fragmented, and non-fragmented forests in central Amazonia, reporting drastic short-term changes in community composition. Fifteen years later, we resampled the same sites using identical techniques and found that, with the regrowth of secondary vegetation between forest fragments, the initial differences had largely disappeared. As the secondary vegetation itself supports dung beetle assemblages similar to those of continuous forest, we conclude that, from the perspective of the dung beetles, the experimentally fragmented area had returned to a continuous state within approximately one decade. These results offer some good news for the conservation of tropical ecosystems, since they suggest that conditions favorable for functionally important arthropods may be quickly restored by secondary regrowth. They also suggest that the preservation of forest fragments and secondary vegetation may provide an important complement to the conservation of intact mature forest. Key words: Amazonas; Brazil; dung beetle; forest fragmentation; matrix habitat; rain forest; recovery; secondary vegetation.

Plant communities on nutrient-poor soils are thought to use nutrients more efficiently to produce biomass than plant communities on nutrient-rich soils. Yet, increased efficiency with declining soil nutrients has not been demonstrated empirically in lowland tropical rain forests, where plant growth is thought to be strongly limited by soil nutrients, especially phosphorus (P). We tested for higher P uptake and use efficiency across a 16-fold soil P gradient in lowland Borneo by measuring the P content of aboveground net primary productivity (fine litter production plus new tree growth; ANPP) for 24 months. Extractable soil P was positively related to litter production, tree growth, and ANPR Efficiency of P response (ANPP/available soil P), uptake (P uptake/available soil P), and use (ANPP/P uptake) increased monotonically with declining soil P and was significantly higher on P-rich soil than P-poor soil. Increased P uptake and use efficiency with declining soil P enabled higher than expected plant productivity on low P soils and thus strongly influenced spatial patterns of aboveground productivity throughout this lowland landscape. A complementary P use efficiency index, the integrated canopy P ([P.sub.c]) use efficiency of production (ANPP/[P.sub.c] x residence time of [P.sub.c]), was similar across the P gradient, but underlying dynamics varied significantly with soil P: on rich soils, ANPP/[P.sub.c] was high and [P.sub.c] residence time was low, while the converse held on poor soils. These contrasting strategies enabled rapid tree growth on nutrient-rich soils, where P limitation is relatively weak, and higher P conservation on nutrient-poor soils, where P limitation is relatively strong. The occurrence of contrasting P use strategies on high and low P soils has important implications for understanding spatial patterns of aboveground productivity, P cycling, and canopy tree species composition across the P gradient. Key words: ANPP; Dipterocarpaceae; ectomycorrhizae; Indonesia; Kalimantan; parent material; phenotypic plasticity; phosphorus; response, uptake and use efficiency; trade off.

Isolation of remnant forest patches, coupled with anthropogenic changes in the surrounding landscape, often leads to changes in the population density of forest-dwelling mammals. At Pasoh Forest Reserve in Peninsular Malaysia, densities of native wild pigs (Sus scrofa) are 10-100 times greater than historical levels due to the local extinction of feline predators and the presence of abundant food sources in areas adjacent to the forest. Female pigs build reproductive nests out of understory vegetation; at Pasoh these nests are constructed primarily of woody saplings several meters tall that pigs snap or uproot, causing substantial local damage. We documented the prevalence of nest building by pigs at Pasoh within a 25-ha area from 1995 to 1998 and investigated the impacts of this mammalian behavior on the understory plant community. In total, 643 pig nests were enumerated, providing an estimate that 6.0 nests x [ha.sup.-1] x [yr.sup.-1] were constructed in the survey area. Pigs avoided constructing nests adjacent to trails but otherwise built nests throughout the 25-ha survey area. A single pig nest contained, on average, 267 [+ or -] 86 (mean [+ or -] 1 SD) woody saplings, of which 45% had been uprooted and 55% had the main stem snapped. The understory area affected by the construction of a single pig nest averaged 244 [+ or -] 112 [m.sup.2], with 53% of all flee-standing woody plants [greater than or equal to] 70 cm tall and Key words: Dipterocarpaceae; lowland rain forest; Malaysia; pig nests; sapling damage; Sus scrofa; tree demography; tropical forests.

The role of herbivores in nutrient cycling in tropical forest ecosystems remains poorly understood. This study investigates several aspects of nutrient cycling along a gradient in herbivore (Alouatta seniculus, red bowler monkey) density among small landbridge islands in Lago Guri, Venezuela. Specifically, two contrasting hypotheses were addressed: (1) herbivores increase the availability of soil nutrients and subsequently primary productivity, and (2) herbivores decrease nutrient availability and primary productivity because they increase the dominance of non-preferred, nutrient-poor, tree species. Although C:N increased with herbivore density, the annual increase in basal area (an indicator of aboveground productivity) increased with herbivore density. According to an analysis of the tree communities on the study islands, herbivory may also be causing a shift in the tree community toward non-preferred species, and thus. over a longer time scale, both nutrient availability and productivity are expected to decline. The influence of herbivores on nutrient cycling and plant productivity has important implications for conservation and rates of carbon sequestration in tropical forests. Key words: Alouatta seniculus; herbivory; Lago Guri, Venezuela; nutrient availability; red howler monkey; tree growth rates; tropical forest fragments.

I examined the effect of repeated long-fallow shifting cultivation on biomass accumulation in a rain-forest landscape occupied for over 200 years in West Kalimantan, Indonesia. The diameters of stems >5 cm dbh were measured in nine secondary forests using a stratified random design of nested plots (3000 [m.sup.2] per site). The stands were 9-12 years old and had experienced from 1 to 10 or more cycles of shifting cultivation. Accounting for differences in soil fertility, analysis of covariance (ANCOVA) demonstrated that aboveground live biomass increment (ABI, in megagrams per hectare per year) was significantly greater after four cycles than after six or more cycles. ABI was lowest after two cycles, highest after one or four cycles and intermediate after 6-10 cycles. Differences were driven by the density and biomass of trees >10 cm dbh, which followed a similar pattern. Although the diameter increment and contribution to total biomass of trees >10 cm dbh increased significantly with inherent soil fertility, variation in the rate of biomass accumulation depended primarily on the number of prior cultivation cycles. An ANCOVA with soil fertility as the main effect was not significant. One hypothesis to explain observed patterns of ABI associated with changes in tree density is a shift, over many cycles, in the dominance of seed-banking vs. resprouting species. Previous work has shown that total phosphorus did not decline after six or more cycles: however, a shift from available to occluded forms may be related to lower ABI in sites with the longest cultivation history. An 11% decline in ABI could substantially alter the carbon-sequestration value of secondary tropical forests as they enter their second century of persistent human disturbance. Key words: biomass accumulation; carbon sequestration: cultivation history; deforestation; life-history turnover; phosphorus: shifting cultivation: tropical secondary rain forest: West Kalimantan, Indonesian Borneo.

1 In 1998, the forests of Lambir Hills National Park experienced a severe drought. Between late January and mid-April, less than one-fifth of the normal expected rainfall was received. To investigate the effects of the drought, survival among 6993 trees ([greater than or equal to] 1 cm d.b.h.) in the drought period (1997-98) was compared with survival among 7270 trees in the same area before the drought (1993-97). 2 Mortality rates for the pre-drought and drought periods were calculated using maximum likelihood techniques. Forest wide mortality rates during the drought were 7.63% [year.sup.-1] as compared to 2.40% [year.sup.-1] during the pre-drought period. Logistic regression was used to investigate habitat effects. During the pre-drought period, soil type was the most important predictor of tree survival, while during the drought period, slope was the most important. 3 The mortality rate of large ([greater than or equal to] 10 cm d.b.h.) rare trees (< 2 individuals [greater than or equal to] 1 cm d.b.h. [ha.sup.-1]) did not differ between pre-drought and drought periods, while that of large common trees (> 35 individuals [greater than or equal to] 1 cm d.b.h. [ha.sup.-1]) increased 6.5 fold in response to the drought suggesting a possible compensatory mechanism maintaining the persistence of rare species. Mortality of large common and rare species however, did not differ significantly during the drought due to small sample sizes. 4 The results of a comparative analysis of the impacts of droughts in four tropical forest sites provide evidence in support of the Intermediate Disturbance hypothesis. Key-words: compensatory mechanisms, diversity, drought, rain forest, Intermediate Disturbance hypothesis

Leaf-cutting ants (Atta spp.) often increase in abundance following deforestation and may have an important effect on forest succession on abandoned land. In this study, we evaluated the effects of leaf-cutting ant (Atta sexdens) activity on physical and chemical properties of soil, root distribution, and tree growth in a 17-yr-old secondary forest in eastern Amazonia, Brazil. We compared the soil properties and root distribution in shafts excavated into five mature nests and at 15 m distanced from each nest mound. We evaluated the nest effects on vegetation measuring the stem diameter growth of nine tree species and predawn leaf water potential of the tree species, Banara guianensis, along a gradient of increasing distance from the nest mounds. The growth of seedlings (Cecropia sp.) in pots containing different proportions of mineral soil and organic matter removed from nest refuse chambers was also compared. The deep soil beneath A. sexdens nests at different depths (100, 200, and 300 cm) presented a low (fivefold, P < 0.01) resistance to penetration and was rich in Ca (three- to fourfold, P = 0.06-0.02), K (7-14-fold, P < 0.05), and Mg (two- to threefold, P = 0.09 for 200 cm depth) when compared to non-nest soil. These changes in nest soil properties were accompanied by increases in coarse root biomass (>2 mm diameter, three- to fourfold) and fine root biomass ( Key words: Amazon basin; bioturbation; forest succession; tropical forest; tropical soil.

Climatically sensitive tropical ecosystems provide important information that may help us to fill the gaps in our knowledge concerning the evolution of rainforests during periods of full glaciation. Small changes in precipitation in the Amazon Basin have immediate consequences for the survival of the Andean cloud forest, because its dominant source of moisture today is the Atlantic Ocean. A 40 k.y. lacustrine record from the Eastern Cordillera in Bolivia in an endemic species-rich and ecologically threatened region shows a dry Last Glacial Maximum, indicating a drastic decrease of the Amazonian moisture source. To explain this aridity, we infer steep temperature gradients between the pole and equator in both hemispheres that would have reduced considerably the size and displacement of the Intertropical Convergence Zone and the austral summer precipitation. This major change in water supply induced a dramatic reduction in species diversity and suggests that the Andean cloud forest did not provide refugia for tropical lowland taxa during full glacial times. Keywords: Andes, lacustrine sediments, palynology, Last Glacial Maximum, cloud forest, Bolivia.

1 Past work on tropical rain forest tree seedlings has been dominated by contrasts between strongly light-demanding and strongly shade-tolerant species. We examined patterns of growth and mortality among shade-tolerant tree seedlings in response to light, and investigated the morphological and physiological correlates of high seedling growth and survival rates across species. 2 Seedlings of 15 tree species from Australian tropical lowland forest were grown for up to 1 year in neutral-density shadehouses at three light levels (10%, 0.8% and 0.2% full daylight). All species showed negligible mortality in the 10% and 0.8% shadehouses, but survival was significantly reduced in 0.2% daylight. 3 Seedling survival rate in 0.2% daylight showed no significant relationship with either the dry mass of seed reserves (embryo plus endosperm), or relative growth rates in dry mass ([RGR.sub.M]) in 0.8% and 10% light. 4 The [RGR.sub.M] values in 0.8% and 10% daylight were strongly positively correlated, and showed a strong negative correlation with the dry mass of seed reserves. Interspecific variation in low-light [RGR.sub.M] was driven by unit leaf rate (rate of accumulation of dry mass per unit area of leaf), whereas interspecific variation in high-light [RGR.sub.M] was most closely correlated with leaf area ratio (leaf area per total plant dry mass). 5 Variation in seedling characters in response to light may have important implications for the coexistence of shade-tolerant tropical tree species. Key-words: Australia, relative growth rate, trade-off, tree seedlings, tropical rain forest

We take advantage of a fortuitous local extinction and recolonization of white-lipped peccaries (WLPs) at the Cocha Cashu Biological Station in southeastern Peru to assess the impact of this high-biomass seed predator on the recruitment of a dominant member of the tree community, the palm Astrocaryum murumuru. WLPs were common at Cocha Cashu in the mid-1970s. In 1978, the species vanished from the entire region and did not reappear until 1990. To assess the impacts of the presence-absence of WLPs on Astrocaryum recruitment, we conducted transect counts of both the number and spatial distribution of palm seedlings in 1978 (when WLPs were present), in 1990 (after a 12-yr absence of WLPs), and in 1999 (after 10 yr of recovery). Other factors affecting recruitment, such as climate variability, differences in tree fecundity, and fluctuations of vertebrate and invertebrate seed predators were also examined as alternative hypotheses for any changes in seedling spatial distribution and abundance. In the absence of WLPs, the density of Astrocaryum seedlings increased 1.7-fold, and the spatial distribution of seedlings with respect to safe sites was significantly altered. After the return of WLPs to the study area, seedling density dropped to its former level, and the spatial distribution of seedlings with respect to safe sites returned to the same pattern found 21 yr earlier in 1978. None of the other factors investigated varied systematically with the census intervals. These results demonstrate that the absence of a single, albeit important, member of a diverse seed predator guild can have a major impact on the demography of a common tree species. We infer that individual seed predators can play central roles in regulating the demography of tropical trees, as envisioned many years ago by Janzen and Connell, and that their extirpation or extinction can have cascading effects in tropical ecosystems. Key words: Astrocaryum murumuru; Cocha Cashu, Peru; ecosystem experiment; El Nino; extinction; keystone; population regulation; regeneration; seed predation; Tayassu pecari; trophic cascade; tropical rain forest.

The abundances and spatial distribution of species is central to biogeography and conservation. Several theories have been offered to explain landscape-scale species distribution patterns. The verification of biogeographic theories, as well as conservation decisions, must be based upon empirical data gathered from necessarily restricted censuses. It is necessary, therefore, to understand the relationship between an underlying landscape-scale pattern and the corresponding pattern it produces upon sampling small subregions. The similarity of species composition between two samples depends not only on the species composition of the underlying landscape from which the samples are drawn, but also on the underlying distribution of species abundances, the degree of conspecific spatial clustering, and sample size. In this paper, we investigate how sampling expectations change depending upon species abundance distributions and upon spatial distributions. We derive analytical results for the expected species overlap between two sampled regions under a wide range of conditions. We compare these results with data from a 50-ha tropical forest census. These methodologies provide useful tools for assessing beta diversity, for testing macro-ecological theory, and for designing landscape-scale sampling schemes. Key words: beta diversity; landscape-scale species distribution; negative binomial; sampling diversity; similiarity indices; spatial aggregation; tropical forest.

1 The simultaneous use of fruits and seeds by invertebrate seed predators and vertebrate seed dispersers produces complex ecological interactions that reduce the predictability of seed fate. 2 Cocosoid palm seeds in the Neotropics are subject to high mortality by bruchid beetle infestation and such attack is the major cause of mortality for seeds of the palm Attalea maripa at our study site in the northern Brazilian Amazon. 3 The exocarp and mesocarp of 1400 fruits were manipulated in different ways to simulate handling by vertebrates. No eggs of the bruchid beetle, Pachymerus cardo, were laid on intact control fruits, while the highest numbers of eggs were received by fruits whose exocarp and mesocarp had been partially removed, as if by primates and rodents (mean of 15.9 and 18.9 eggs [fruit.sup.-1], respectively, during the peak fruiting season). Fruits with intact mesocarp but no exocarp, and fruits with all mesocarp and exocarp removed, received low numbers of eggs (mean of 4.6 and 6.6 eggs per fruit, respectively, during the peak fruiting season). Thus both exocarp and mesocarp deter oviposition, and removal of these fruit structures increases fruit susceptibility to infestation. 4 Oviposition rates declined as the fruiting season progressed, but oviposition preferences remained the same. Seed mortality was high for any fruit on which eggs were laid. 5 Large rodents and primates, which have been considered among the most effective seed dispersers for large-seeded Neotropical trees such as palms, actually increased the susceptibility of seeds to bruchid beetle attack. Removal of (intact) seeds by other dispersers may be necessary to ensure seed survival. 6 These results indicate that the reliability of seed dispersers cannot be gauged without a complete understanding of variables that affect seed viability. Key-words: Attalea maripa, frugivory, fruit traits, seed dispersal, tropical forests

We inventoried two Amazonian tree communities separated by ~1400 km of continuous lowland tropical forest, in an effort to understand why one was more diverse than the other. Yasuni National Park, near the equator in eastern Ecuador, has one of the most diverse tree communities in the world. Manu National Park, at 12[degrees] S in Peru's Madre de Dios region, is only moderately diverse by upper Amazonian standards. Following the field inventories, a database of morphological, ecological, and other traits was compiled from the taxonomic literature for 1039 species from the plots. Our goal were (1) to describe how terra firme tree communities at the two sites differed in compositions, diversity, and structure; (2) to characterize the 'extra' species responsible for the higher diversity at Yasuni; and (3) to assess, in the light of those observations, some explanations for why forests near the equator are so diverse. Yasuni has ~1.4 times as many tree species as Manu at all three spatial scales we examined: local (1 ha), landscape ( Several models that offer explanations for geographic variation in tropical tree species diversity are assessed in light of these data. Most do a poor job of accounting for the patterns revealed by the inventories. We speculate that the most important factor in producing the higher diversity in Yasuni is its rainier, aseasonal climate, and we discuss two specific rainfall-related mechanisms that appear to be supported by the data: (1) year-round water availability allowing more species to persist in the understory at Yasuni and (2) a newly described 'mixing effect' related to the higher stem density there. Key words: Amazon basin; Ecuador; Manu National Park, Peru; Peru; species diversity; tropical forests; tropical trees; Yasuni National Park, Ecuador.

We studied monthly and annual variation in density estimates of nine forest bird species along an elevational gradient in an east Maui rainforest. We conducted monthly variable circular-plot counts for 36 consecutive months along transects running downhill from timberline. Density estimates were compared by month, year, and station for all resident bird species with sizeable populations, including four native nectarivores, two native insectivores, a non-native insectivore, and two non-native generalists. We compared densities among three elevational strata and between breeding and nonbreeding seasons. All species showed significant differences in density estimates among months and years. Three native nectarivores had higher density estimates within their breeding season (December-May) and showed decreases during periods of low nectar production following the breeding season. All insectivore and generalist species except one had higher density estimates within their March-August breeding season. Density estimates also varied with elevation for all species, and for four species a seasonal shift in population was indicated. Our data show that the best time to conduct counts for native forest birds on Maui is January-February, when birds are breeding or preparing to breed, counts are typically high, variability in density estimates is low, and the likelihood for fair weather is best. Temporal variations in density estimates documented in our study site emphasize the need for consistent, well-researched survey regimens and for caution when drawing conclusions from, or basing management decisions on, survey data. Key words: bird counts, density estimation, Hawaiian honeycreepers, phenology, rainforest, variable circular-plot.

Theories accounting for the maintenance of high tree diversity in tropical rain forests range from those proposing that tropical trees are highly co-evolved niche specialists, to those proposing that they are mostly generalist, undergoing random drift. We test these hypotheses at a meaningful, community-wide scale using data on the spatial patterns and habitat preferences of all species of Aporosa (Euphorbiaceae) growing on two large rain forest plots in Malaysia. Second-order spatial pattern analyses using a method based on Ripley's K function showed that Aporosa species formed spatially distinct assemblages, and a randomization procedure suggested that these assemblages were explained by biases in their distributions in relation to habitat types. Soil type, as determined by parent material, was an important determinant of habitat preferences, although topography and forest structure also accounted for some variation. We conclude that niche differentiation is an important mechanism contributing to the coexistence of Aporosa species at the community scale. However, spatial separation due to these differential habitat biases accounted for only a portion of the high species richness observed in this genus, so other mechanisms must also be sought to account fully for the maintenance of tropical tree species richness. Key words: Aporosa; coexistence; habitat preference; Malaysia; niche; rain forest; random drift; Ripley's K function; spatial pattern; species diversity; tropical forest.

We investigated patterns of mammal assemblage structure on the Atherton Tableland in the Wet Tropics biogeographic region of northeastern Australia. We used live trapping and quantitative estimates of stratified vegetation density to examine the relationships between the structure of the mammal assemblage and habitat structure over three nested spatial scales across a natural vegetation gradient from rain forest to dry, open forest. The narrow transition zone enabled us to examine the relationships between mammal assemblage structure and habitat structure while minimizing the confounding effects of distance, climate, and biogeographic history. The structure of the mammal assemblages was closely related to vegetation structure across and within habitats, and over all spatial scales examined. Vegetation complexity and heterogeneity both influenced assemblage structure, but the relationships varied with spatial scale. Species richness was highest in the open forest and decreased across the gradient into the rain forest. Point diversity was only weakly explained by vegetation structure, whereas >80% of the variation in species richness at the local scale could be explained by vegetation structure. Local-scale species richness of ground-dwelling mammals was mostly a product of the spatial variability in assemblage structure ([beta] diversity), which was associated with the spatial variability in vegetation structure. Local-scale habitat heterogeneity thus promoted local-scale species richness via the close ecological interaction between mammals and habitat structure. The multiscale approach used here, and the nesting of spatial variability in within-habitat vegetation structure, enabled us to demonstrate the scale-dependent effects of spatial habitat heterogeneity and complexity on the structure and diversity of the small-mammal assemblage. Key words: assemblage structure; Australia; diversity; ecotone; gradients; habitat complexity; habitat heterogeneity; patchiness; rain forest; small mammals; spatial scale; vegetation structure.

The effects of neighbor vegetation during succession were studied in old-field and rain forest sites of central Amazonia. We investigated how plant litter and the availability of soil nutrients (P and K) influenced interactions between neighbor vegetation and colonizing species. We monitored the establishment and growth of seedlings of four tree species, sown in old-field and forest plots in which vegetation, plant litter, and soil P and K were experimentally manipulated. In the old field, removal of vegetation significantly decreased seedling establishment of Oenocarpus bataua, Socrathea exorrhiza, and Aspidosperma discolor (suggesting facilitation in these late successional species) but had no effect on Inga edulis (a mid successional species). In contrast, neighboring vegetation inhibited the growth of all sown species: removal significantly increased biomass. In the forest site, removal of forest vegetation had no effect on establishment but significantly increased seedling mass, suggesting inhibition. Plant litter removal significantly decreased seedling establishment of all species in the old field, and of S. exorrhiza and I. edulis in the forest, suggesting positive effects. A significant interaction between plant litter and vegetation removal for O. bataua and S. exorrhiza in the old field showed that litter may also contribute to facilitation. Seedling mass of the three late-successional species was consistently not enhanced by P and K addition. In I. edulis, however, mass increased 2.5 times after P and K addition when vegetation was removed but did not vary in intact old-field vegetation. Seedling establishment in the old field was significantly higher in S. exorrhiza and A. discolor compared to the forest, while plant biomass in S. exorrhiza, A. discolor, and I. edulis was significantly higher. Neither plant litter nor P and K addition could account for these differences. We conclude that facilitation and competition may operate during the early stages of forest succession in Amazonia, that plant litter contributes to the facilitation process, and that soil P and K do not influence the inhibition process, suggesting that light competition may be important. As succession proceeds, the effects of neighbor vegetation switch from positive to negative. Key words: Aspidosperma discolor; Amazonia; competition and facilitation; Inga edulis; Oenocarpus bataua; old-field succession; plant litter; root: shoot allocation; seedling establishment; Socratea exorrhiza; soil fertility; succession; tropical rain forest.

Species richness is an important characteristic of ecological communities, but it is difficult to quantify. We report here a thorough inventory of a tropical rain forest ant fauna and use it to evaluate species richness estimators. The study was carried out in ~1500 ha of lowland rain forest at La Selva Biological Station, Costa Rica. Diverse methods were used, including canopy fogging, Malaise traps, Berlese samples, Winkler samples, baiting, and manual search. Workers of 437 ant species were encountered. The abundance distribution was clearly lognormal, and the distribution emerged from a veil line with each doubling of sampling effort. Three richness estimates were calculated: the area under the fitted lognormal distribution, the asymptote of the Michaelis-Menten equation fit to the species accumulation curve, and the Incidence-based Coverage Estimator (ICE). The performance of the estimators was evaluated with sample-based rarefaction plots. The inventory was nearly complete because the species accumulation curve approached an asymptote, the richness estimates were very close to the observed species richness, and the uniques and duplicates curves were both declining. None of the richness estimators was stable in sample-based rarefaction plots, but regions of stability of estimators occurred. The explanation of rarity is one key to understanding why richness estimates fail. Fifty-one species (12% of the total) were still uniques (known from only one sample) at the end of the inventory. The rarity of 20 of these species was explained by 'edge effects': 'methodological edge species' (possibly abundant at the site but difficult to sample because of their microhabitat), and 'geographic edge species,' known to be common in habitats or regions outside of La Selva. Rarity of 31 species remained unexplained. Most of the 51 rare species were known from additional collections outside of La Selva, either in other parts of Costa Rica or in other countries. Only six species were 'global uniques,' known to date from only one sample on Earth. The study demonstrates that patterns of species occurrence early in an inventory may be inadequate to estimate species richness, but that relatively complete inventories of species-rich arthropod communities are possible if multiple sampling methods and extensive effort are applied. Key words: abundance distribution; ants; biodiversity; Costa Rica; Formicidae; incidence-based coverage estimator; inventories, species; La Selva; lognormal; Michaelis-Menten: richness estimation; species accumulation curves; tropical rain forest.

We examined 11 species in four genera of rattans (Calamus, Daemonorops, Korthalsia, Plectocomia) growing in their native rainforest habitat in Singapore. Using aqueous safranin dye, we found that >95% of all vascular bundles at the base of a mature stem were functioning to transport water. We determined the frequency of vessel lengths in the long stems of these climbing palms by infiltration with dilute latex paint. Separate length distributions were made for metaxylem and protoxylem vessels; in both, there were many short and a few long vessels. The longest protoxylem vessels ranged from 7.5 to 62 cm in length, but one stem had an exceptional protoxylem vessel measuring 3.0 m. Maximum metaxylem vessel diameters were positively correlated to maximum vessel lengths in these species. The longest metaxylem vessel was found in K. rigida and was 3.96 m in length and was constructed from ~1200 vessel elements (cells). The widest vessel in that same stem was 532 [micro]m in diameter. Long, wide vessels decrease resistance and increase water transport efficiency. In addition, we suggest that wide metaxylem vessels may have an important function in water storage. Key words: Arecaceae; Calamoideae; Calamus; Daemonorops; Korthalsia; Palmae; Plectocomia; vessels; xylem.

The `Akohekohe (Palmeria dolei) is an endangered Hawaiian honeycreeper endemic to the montane rain forests of east Maui in the Hawaiian Islands. We investigated `Akohekohe nesting ecology using color-banded birds for the first time as a background to understanding the species' conservation. From 1994-1997 we color-banded 78 individuals, located and monitored 46 active nests, and took behavioral data during 534 hr of nest observation at Hanawi Natural Area Reserve, near the center of the species' range. `Akohekohe nesting behavior and life history closely resembled that of `Apapane (Himatione sanguinea) and related honeycreepers. The birds were monogamous within and among years, and we found no evidence of polyandry, polygyny, or helpers at the nest. The nesting season extended from November to early June. Females performed all incubation and brooding. Males provisioned females and nestlings, and they were more active than females in feeding fledglings during the two-week period of parental dependency. Modal clutch size, as determined from egg counts at three nests and by counting begging chicks at other nests, was two eggs, and parents frequently fledged two chicks. We found an overall nest success rate of 68% by the Mayfield method, a high rate compared with other Hawaiian honeycreepers and continental passerines. An average of 1.1 chicks fledged per active nest, and at least 42% of nesting pairs made two or more nesting attempts per season. Rats (Rattus spp.) were abundant at the study site, and we confirmed their depredating some `Akohekohe nests, so we did not expect to find such a high rate of nest success. The estimated annual probability of adult survival was also high, at 0.95 [+ or -] 0.10 (SE). Key words: `Akohekohe, breeding success, demography, endangered, Hawaiian honeycreepers, nest success, Palmeria dolei.

Research indicates that the tropical tree species Mimosoideae are reliant on the seed dispersal roles of frugivores to maintain plant genetic diversity, abundance, and fitness ability. In regions where seed dispersers such as the spider monkey have been eradicated due to subsistence hunting, Mimosoid saplings were found to be self-incompatible, and a fewer number of saplings were found under parent trees.

Research indicates that both bats and birds play important roles in seed dispersal, particularly in pasture regions. Since they disperse seeds of primary and pioneer species such as herbs, shrubs and trees, bats and birds may make significant contributions to woody vegetation recovery in disturbed regions of tropical forests.

Studies on bat species near Chiapas, Mexico, show that bat species diversity, richness and numbers of rare bat species are positively correlated with vegetation scores, making them a reliable indicator species. Other advantages include easy sampling, quick results and low costs.

Research is presented on the impact of three different types of human settlements on the surrounding environment, using as examples indigenous Maya villages, mestizo villages, and mixed-composition villages near Campeche, Mexico, and the effects of the hunting practices of each type of village. Data showed that the indigenous village had minimal impact on species number and biodiversity than the other two village types.

An overview is presented on the effects of human encroachment on rain forest mammal survival and biodiversity. Harmful activities include logging, hunting and overharvesting, colonization of frontier regions, and roads, which threaten wildlife through physical threats posed by traffic and by increasing human access to pristine areas.

A assessment is presented on the value of historical and ecological biogeography and molecular genetics on rain forest research, particularly concerning historical prescribed burnings. These methods are expected to delineate the effects of early human settlement and latter-day colonization on Australia's landscape.

An analysis is presented on identifying and defining rain forests in Australia. Topics include the types of trees which constitute a rain forest, historical prescribed burnings by Aborigines, paleobotanical records, nutrient cycling, topography and climatic parameters.