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Hendriks, Thomas. Rainforest Capitalism: Power and Masculinity in a Congolese Timber Concession. Durham, NC: Duke University Press, 2022. Dedicated to 'loggers, wherever they are,' Thomas Hendriks's Rainforest Capitalism examines the [...]

Taxa with smaller individuals tend to have shorter generation times and higher local abundance and diversity. The scaled specialization hypothesis (SSH) posits that taxocenes of smaller individuals should differentiate more rapidly and thoroughly along physiochemical gradients of a given age and extent. In a Panama rainforest, we evaluated how bacteria, fungi, and ants responded to two such gradients: one topographic and the other arising from nine years of NPK fertilization. Terminal restriction fragment length polymorphism (T-RFLP) delineated bacteria and fungi operational taxonomic units (OTUs); traditional taxonomy delineated the ants. Bacteria had higher local species richness than fungi and ants (averaging 48 vs. 30 vs. 60TUs in Key words: ants; bacteria; biogeochemistry; diversity; fungi; niche; species composition.

We examine the evidence for the possibility that 21st-century climate change may cause a large-scale 'dieback' or degradation of Amazonian rainforest. We employ a new framework for evaluating the rainfall regime of tropical forests and from this deduce precipitation-based boundaries for current forest viability. We then examine climate simulations by 19 global climate models (GCMs) in this context and find that most tend to underestimate current rainfall. GCMs also vary greatly in their projections of future climate change in Amazonia. We attempt to take into account the differences between GCM-simulated and observed rainfall regimes in the 20th century. Our analysis suggests that dry-season water stress is likely to increase in E. Amazonia over the 21st century, but the region tends toward a climate more appropriate to seasonal forest than to savanna. These seasonal forests may be resilient to seasonal drought but are likely to face intensified water stress caused by higher temperatures and to be vulnerable to fires, which are at present naturally rare in much of Amazonia. The spread of fire ignition associated with advancing deforestation, logging, and fragmentation may act as nucleation points that trigger the transition of these seasonal forests into fire-dominated, low biomass forests. Conversely, deliberate limitation of deforestation and fire may be an effective intervention to maintain Amazonian forest resilience in the face of imposed 21st-century climate change. Such intervention may be enough to navigate E. Amazonia away from a possible 'tipping point,' beyond which extensive rainforest would become unsustainable. carbon dioxide | drought | fire | tropical forests | adaptation doi/10.1073/pnas.0804619106

The 51.9 Ma Laguna del Hunco (LH) and 47.5 Ma Rio Pichileufu (RP) floras from Patagonia, Argentina are unusually rich, angiosperm-dominated assemblages with living relatives in the low-latitude West Pacific, neotropics, and temperate southern latitudes. The diverse gymnosperms in these floras are important for Gondwanan biogeographic history and paleoclimatic interpretations. 'Libocedrus' prechilensis Berry 1938 (Cupressaceae), previously known only from the holotype (RP), a vegetative branch, is revised here based on new material from both localities, including a seed cone attached to a shoot with cuticle (LH). Characters of these fossils are diagnostic of monotypic Papuacedrus (highlands of New Guinea and Moluccas). Living P. papuana is most abundant in cloud forests receiving up to 4 m rainfall annually, whereas Austrocedrus (Libocedrus) chilensis, the basis of comparison when the fossil species was named, inhabits dry, cold steppe margins to mediterranean climates in southern South America. We establish Papuacedrus prechilensis comb. nov., which simultaneously invalidates a southern South American connection for the fossil floras and reveals a link to West Pacific montane rainforests. Combined evidence indicates a biome similar to extant subtropical, or tropical montane, rainforests that persisted for at least 4.4 Myr, linking elevated floral richness to abundant rainfall. Key words: Austrocedrus; Cupressaceae; Eocene; Laguna del Hunco; Libocedrus; paleoclimate; Papuacedrus; Patagonia; Rio Pichileufu; subtropical rainforest. doi: 10.3732/ajb.0900085

The idea that the Pennsylvanian tropical lowlands were temporally dominated by rainforest (i.e., the Coal Forest) is deeply ingrained in the literature. Here we challenge two centuries of research by suggesting that this concept is based on a taphonomic artifact, and that seasonally dry vegetation dominated instead. This controversial finding arises from the discovery of a new middle Pennsylvanian (Moscovian) fossil plant assemblage in southeast Illinois, United States. The assemblage, which contains xerophytic walchian conifers, occurs in channels incised into a calcic Vertisoi below the Baker Coal. These plants grew on seasonally dry tropical lowlands inferred to have developed during a glacial phase. This xerophytic flora differs markedly from that of the typical clubmoss-dominated Coal Forest developed during deglaciation events. Although preserved only very rarely, we argue that such xerophytic floras were temporally as dominant, and perhaps more dominant, than the iconic Coal Forests, which are overrepresented in the fossil record due to taphonomic megabias. These findings require the iconography of Pennsylvanian tropical lowlands to be redrawn.

The distribution of the diversity and abundance of life on Earth is thought to be shaped by the patterns of plant growth (net primary production, NPP) in the oceans and on land. The well-known latitudinal gradient of species diversity reaches its maximum in tropical rain forests, which are considered to be the most productive ecosystems on the planet. However, this high tropical productivity on land is the opposite of the well-documented distribution of marine productivity, which is greatest in the high-latitude oceans around the poles. This paradox can be resolved by a reevaluation of the terrestrial productivity gradient. Compilations of direct measurements of forest NPP show that annual NPP in tropical forests is no different than annual NPP in temperate forests, contrary to recent syntheses and to the output of global vegetation models. Other properties of forest ecosystems, such as basal area of trees, wood density, and the ratio of wood to leaf production, as well as animal properties such as body size, population density, and reproductive rates, support the conclusion that ecologically relevant terrestrial productivity is actually highest in the temperate latitudes, reaching a maximum between 30[degrees] and 50[degrees] before declining toward the poles. This 'reversal' of the latitudinal productivity gradient, if substantiated by a systematic global sampling effort, will necessitate a major reevaluation of ecological and evolutionary theory, as well as conservation strategies and international development policies. Key words: biomass; forest; gradients; latitude; marine; net primary production; NPP; secondary production; species diversity; terrestrial.

Amazon forests are a key but poorly understood component of the global carbon cycle. If, as anticipated, they dry this century, they might accelerate climate change through carbon losses and changed surface energy balances. We used records from multiple long-term monitoring plots across Amazonia to assess forest responses to the intense 2005 drought, a possible analog of future events. Affected forest lost biomass, reversing a large tong-term carbon sink, with the greatest impacts observed where the dry season was unusually intense. Relative to pre-2005 conditions, forest subjected to a 100-millimeter increase in water deficit lost 5.3 megagrams of aboveground biomass of carbon per hectare. The drought had a total biomass carbon impact of 1.2 to 1.6 petagrams (1.2 x [10.sup.15] to 1.6 x [10.sup.15] grams). Amazon forests therefore appear vulnerable to increasing moisture stress, with the potential for large carbon losses to exert feedback on climate change.

Plant root simulator (PRS) probes, a resin membrane technology, are increasingly used to measure soil nutrient availability in agricultural and nonagricultural systems. Like other resin technologies, the charged surface is meant to sorb nutrients until saturation; however, there is evidence that it acts as a dynamic exchanger in soils with low nutrient availability. This study compared the nutrient sorption dynamics of PRS probes during an 8-wk period in a young Andisol forest soil on the island of Hawaii with and without P fertilization. Resin bags, a more established technology, were used to measure nutrient availability as a comparison. The PRS probe sorption dynamics differed for the six nutrients measured. Except for N[O.sub.3], nutrient sorption appeared to reach equilibrium with the soil labile pools after 4 wk. Resin bags acted as an infinite sink for N[H.sub.4.sup.+], N[O.sub.3.sup.-], and P[O.sub.4.sup.3-] and sorbed more than the PRS probes. Both technologies detected an increase in P availability due to fertilization. A comparison of nutrient availability from PRS probes and resin bags correlated poorly. Isolation of the PRS probes and resin bags from root activity did not improve measurements of labile nutrients. More research is required to understand the processes behind the apparent desorption of nutrients from the PRS probes in acidic forest soils. If used for a minimum of 4 wk, however, the PRS probes appear to provide an equilibrium measure of labile soil nutrients with high sensitivity to treatment differences. Abbreviations: PRS, plant root simulator.

Tropical rain forests represent some of the most diverse ecosystems on earth, yet mechanistic links between tree species identity and ecosystem function in these forests remains poorly understood. Here, using free-living nitrogen (N) fixation as a model, we explore the idea that interspecies variation in canopy nutrient concentrations may drive significant local-scale variation in biogeochemical processes. Biological N fixation is the largest 'natural' source of newly available N to terrestrial ecosystems, and estimates suggest the highest such inputs occur in tropical ecosystems. While patterns of and controls over N fixation in these systems remain poorly known, the data we do have suggest that chemical differences among tree species canopies could affect free-living N fixation rates. In a diverse lowland rain forest in Costa Rica, we established a series of vertical, canopy-to-soil profiles for six common canopy tree species, and we measured free-living N fixation rates and multiple aspects of chemistry of live canopy leaves, senesced canopy leaves, bulk leaf litter, and soil for eight individuals of each tree species. Free-living N fixation rates varied significantly among tree species for all four components, and independent of species identity, rates of N fixation ranged by orders of magnitude along the vertical profile. Our data suggest that variations in phosphorus (P) concentration drove a significant fraction of the observed species-specific variation in free-living N fixation rates within each layer of the vertical profile. Furthermore, our data suggest significant links between canopy and forest floor nutrient concentrations; canopy P was correlated with bulk leaf litter P below individual tree crowns. Thus, canopy chemistry may affect a suite of ecosystem processes not only within the canopy itself, but at and beneath the forest floor as well. Key words: Costa Rica; ecosystem function; free-living; nitrogen fixation; phosphorus; tree species; tropical rain forest.

A well-known, but largely untested, prediction in plant reproductive ecology is that dioecious taxa should produce larger, more, higher-quality, or better-defended seeds than cosexual taxa. Using a data set composed of 972 species in 104 families, representing the flora of the Tambopata Wildlife Reserve (Madre de Dios, Peru), we evaluated the first component of this prediction, examining ecological and evolutionary relationships between breeding system and mean seed size with two kinds of tests. First, we conducted cross-species analyses to determine whether species with different breeding systems differed significantly with respect to mean individual seed size. Second, we used a hypothesized phylogeny to identify pairs of the most closely related taxa or clades within the Tambopata community that differed with respect to breeding system. Comparing pair members allowed us to determine whether evolutionary divergence in breeding system (between taxa with unisexual vs. cosexual individuals) was consistently associated with evolutionary change in seed size. In both analyses, we controlled for potentially confounding effects of growth form by examining these relationships within woody and nonwoody taxa. Cross-species analyses revealed that dioecious species produced larger seeds than cosexual species among woody species, shrubs, lianas (each growth form analyzed separately), and all species pooled, but not among trees. Phylogenetically independent contrasts upheld the significant association between breeding system and seed size among woody taxa, lianas, and all taxa pooled, but not among shrubs. We discuss the implications of our findings for evolutionary hypotheses regarding associations between dioecy and seed size. Key words: angiosperms, breeding system, dioecy; monoecy; plant growth forms; rain forest; seed size.

According to neutral quantitative genetic theory, population bottlenecks are expected to decrease standing levels of additive genetic variance of quantitative traits. However, some empirical and theoretical results suggest that, if nonadditive genetic effects influence the trait, bottlenecks may actually increase additive genetic variance. This has been an important issue in conservation genetics where it has been suggested that small population size might actually experience an increase rather than a decrease in the rate of adaptation. Here we test if bottlenecks can break a selection limit for desiccation resistance in the rain forest-restricted fly Drosophila bunnanda. After one generation of single-pair mating, additive genetic variance for desiccation resistance increased to a significant level, on average higher than for the control lines. Line crosses revealed that both dominance and epistatic effects were responsible for the divergence in desiccation resistance between the original control and a bottlenecked line exhibiting increased additive genetic variance for desiccation resistance. However, when bottlenecked lines were selected for increased desiccation resistance, there was only a small shift in resistance, much less than predicted by the released additive genetic variance. The small selection response in the bottlenecked lines was no greater than that observed in the control lines. Thus bottlenecks might produce a statistically detectable change in additive genetic variance but this change has no impact on the response to selection.

Despite their narrow distribution, Australian rainforests still contain considerable levels of diversity and include many ancient, but often rare, lineages. Very little is known about the general biology of rainforest species, yet their long-term management depends on a better understanding of the main factors leading to rarity. For instance, are they highly endemic taxa, at the early stages of expansion, nearing the end of a period of decline, or persisting at low numbers over the long term? In this study we combine molecular, environmental, and ecological data to identify the factors responsible for the narrow distribution of a paleoendemic rainforest tree: Elaeocarpus sedentarius (Elaeocarpaceae). Between-population and between-generation comparisons of genetic diversity across all known populations of E. sedentarius show evidence of mutation--drift equilibrium rather than evidence of a recent bottleneck. Similarly, floristic and environmental data negate the hypothesis of rarity as a consequence of highly specialized habitat requirements. Instead, genetic structure and the available ecological data support the hypothesis of dispersal limitation as the main cause of endemism and that the species may have attained genetic equilibrium without realizing its full niche potential. We suggest that these factors are likely to explain narrow endemism in a broader range of taxa. Key words: dispersal; endemism; Elaeocarpaceae; Elaeocarpus; genetic structure; microsatellites; persistence; rarity.

The long-term trend in tropical forest area receives less scrutiny than the tropical deforestation rate. We show that constructing a reliable trend is difficult and evidence for decline is unclear, within the limits of errors involved in making global estimates. A time series for all tropical forest area, using data from Forest Resources Assessments (FRAs) of the United Nations Food and Agriculture Organization, is dominated by three successively corrected declining trends. Inconsistencies between these trends raise questions about their reliability, especially because differences seem to result as much from errors as from changes in statistical design and use of new data. A second time series for tropical moist forest area shows no apparent decline. The latter may be masked by the errors involved, but a 'forest return' effect may also be operating, in which forest regeneration in some areas offsets deforestation (but not biodiversity loss) elsewhere. A better monitoring program is needed to give a more reliable trend. Scientists who use FRA data should check how the accuracy of their findings depends on errors in the data. global environmental monitoring | sustainability indicators | tropical deforestation

Integral Ecology uses multiple perspectives to analyze environmental problems. Four of Integral Ecology's major analytical perspectives (known as the quadrants) correspond to the four divisions of the liberal arts and sciences: fine arts, natural science, social science, and humanities. Integral Ecology also utilizes the analytical perspective provided by the idea of cultural moral development. This perspective helps to reveal how stakeholders at different developmental stages disclose a phenomenon, in this case, a tropical forest that loggers propose to clear-cut. Integral Ecology takes into account all pertinent perspectives, in order to arrive at the best possible solution to environmental problems and conflicts. KEYWORDS: Environmental problems. Integral Ecology, Integral Theory, perspectivalism, vMemes.

Tree architecture determines a tree's light capture, stability, and efficiency of crown growth. The hypothesis that light demand and adult stature of tree species within a community, independently of each other, determine species' architectural traits was tested by comparing 53 Liberian rain forest tree species. We evaluated whether species differed in their tree height, crown depth, and crown diameter, when compared at a standardized size of 15-cm diameter at breast height; and how their architecture changed early during ontogeny. Tree height was positively correlated with adult stature and light demand. By producing a relatively slender stem, large-stature species are able to rapidly reach their reproductive size, at a low cost for construction and support. Light-demanding species need a slender stern to be able to attain or maintain a position in the canopy. Both crown depth and crown diameter were negatively correlated with adult stature, but not with light demand. This is in contrast with the hypothesis that shade-tolerant species should have a shallow crown to reduce self-shading in a light-limited environment. Investing energy in height growth rather than lateral crown growth allows a rapid vertical stem extension, but crown diameter has to be sufficiently small to reduce the risk of mechanical failure. All architectural patterns were maintained during ontogeny. The key factors driving interspecific differences in tree architecture are the costs of height extension and mechanical stability. In general, light demand and adult stature represent independent axes of architectural differentiation, affecting tree architecture in different ways. Key words: crown traits; Liberia; plant strategy; shade tolerance; tree architecture; light demand vs. adult stature; tree height; tropical rain forest.

Recent global-scale analyses indicate that climate variability affects net carbon storage but regard temperature and precipitation to be the main contributors. Seasonal and interannual variation in light availability may also limit C[O.sub.2] uptake. As an experimental test of light limitation by cloud cover during tropical rainy seasons and by the unusually heavy cloud cover associated with La Nina, we installed high-intensity lamps above the forest canopy to augment light for Luehea seemannii, a tropical canopy tree species, during cloudy periods of 1999-2000. Light augmentation only partially compensated for the reduction in photosynthetic photon flux density caused by clouds. Nonetheless, leaves acclimated to the augmented irradiance, and photosynthesis, vegetative growth, and reproduction increased significantly. Light, rather than water, temperature, or leaf nitrogen, was the primary factor limiting C[O.sub.2] uptake during the rainy season. El Nino | canopy | photosynthesis | light limitation