Aim Tropical forests store 25% of global carbon and harbour 96% of the world's tree species, but it is not clear whether this high biodiversity matters for carbon storage. Few studies have teased apart the relative importance of forest attributes and environmental drivers for ecosystem functioning, and no such study exists for the tropics. Location Neotropics. Methods We relate aboveground biomass (AGB) to forest attributes (diversity and structure) and environmental drivers (annual rainfall and soil fertility) using data from 144,000 trees, 2050 forest plots and 59 forest sites. The sites span the complete latitudinal and climatic gradients in the lowland Neotropics, with rainfall ranging from 750 to 4350 mm year−1. Relationships were analysed within forest sites at scales of 0.1 and 1 ha and across forest sites along large‐scale environmental gradients. We used a structural equation model to test the hypothesis that species richness, forest structural attributes and environmental drivers have independent, positive effects on AGB. Results Across sites, AGB was most strongly driven by rainfall, followed by average tree stem diameter and rarefied species richness, which all had positive effects on AGB. Our indicator of soil fertility (cation exchange capacity) had a negligible effect on AGB, perhaps because we used a global soil database. Taxonomic forest attributes (i.e. species richness, rarefied richness and Shannon diversity) had the strongest relationships with AGB at small spatial scales, where an additional species can still make a difference in terms of niche complementarity, while structural forest attributes (i.e. tree density and tree size) had strong relationships with AGB at all spatial scales. Main conclusions Biodiversity has an independent, positive effect on AGB and ecosystem functioning, not only in relatively simple temperate systems but also in structurally complex hyperdiverse tropical forests. Biodiversity conservation should therefore be a key component of the UN Reducing Emissions from Deforestation and Degradation strategy.

No abstract

A severe hurricane affected Jamaican montane rain forests in 1988. We made local and widespread measurements of tree condition in three periods: prehurricane 1974–1984 (preh.); hurricane 1984—1989 (h.); and post—hurricane 1989—1992 (post—h.). In the h. period, 7.22% of stems and 4.72% of the total basal area died; crown loss was the most frequent cause of mortality. Among individual tree species, the hurricane caused a large range in mortality (0—26%) and non—fatal damage. Post—h. mortality was greater than mortality in the h. period, and varied among species. Post—h. stem growth rates (all species combined) were more than double the prehurricane rates, but species showed a considerable range from no significant increase to eight times greater. We classified 20 common tree species using damage scores (normalized h. mortality, plus normalized change in mortality from preh. to post—h., plus normalized complete crown loss in h.) and response scores (normalized change, preh. to post—h., in recruitment to the ≥ 3 cm dbh size class, plus normalized change in growth rate from preh. to post—h., plus normalized frequency of sprouts). Species were assigned to one of four groups: resistant (11 species), with low damage and low response; susceptible (5 species), with high damage and low response; resilient (1 species), with high damage and high response; and usurpers (3 species), with low damage and high responsiveness. The grouping of species was broadly related to their regeneration requirements. Most species with seedlings usually found under closed canopy were resistant; three of the four species with seedlings usually found on landslides were also resistant. Species with seedlings most frequently found in gaps included resilient, susceptible, and usurper species, but were not usually resistant. It is likely that the three species classified as usurpers will increase their relative abundance in the forest in the next decades and that Cyathea pubescens, which was very susceptible, will decrease in relative abundance of adults. Most of the other species are likely to have small changes in their relative abundances. Thus, at present, hurricanes have few long—term effects on the forests, although a change in the disturbance regime may alter this.

Background and aimRecycled sources of phosphorus (P), such as struvite extracted from wastewater, have potential to substitute for more soluble manufactured fertilisers and help reduce the long-term threat to food security from dwindling finite reserves of phosphate rock (PR). This study aimed to determine whether struvite could be a component of a sustainable P fertiliser management strategy for arable crops.MethodsA combination of laboratory experiments, pot trials and mathematical modelling of the root system examined the P release properties of commercial fertiliser-grade struvite and patterns of P uptake from a low-P sandy soil by two different crop types, in comparison to more soluble inorganic P fertilisers (di-ammonium phosphate (DAP) and triple super phosphate (TSP)).ResultsStruvite had greatly enhanced solubility in the presence of organic acid anions; buckwheat, which exudes a high level of organic acids, was more effective at mobilising struvite P than the low level exuder, spring wheat. Struvite granules placed with the seed did not provide the same rate of P supply as placed DAP granules for early growth of spring wheat, but gave equivalent rates of P uptake, yield and apparent fertiliser recovery at harvest, even though only 26 % of struvite granules completely dissolved. Fertiliser mixes containing struvite and DAP applied to spring wheat have potential to provide both optimal early and late season P uptake and improve overall P use efficiency.ConclusionsWe conclude that the potential resource savings and potential efficiency benefits of utilising a recycled slow release fertiliser like struvite offers a more sustainable alternative to only using conventional, high solubility, PR-based fertilisers.Electronic supplementary materialThe online version of this article (doi:10.1007/s11104-015-2747-3) contains supplementary material, which is available to authorized users.

Global financial donors have invested billions of dollars in “Sustainable Forest Management” to conserve forests and the ecosystem services they provide. A major contributing mechanism, community forest management (CFM), aims to provide global environmental benefits (reduce deforestation, maintain biodiversity), while also improving local human welfare (alleviate poverty). We have systematically reviewed available evidence of CFM effectiveness and consider the implications of our findings for future investment in CFM programs. There is evidence of CFM being associated with greater tree density and basal area but not with other indicators of global environmental benefits. We found no data on local human welfare amenable to meta‐analysis. Poor study design, variable reporting of study methodology or context, and lack of common indicators make evidence synthesis difficult. Given the policy interest in and the planned donor expenditure on CFM, evaluation must be improved so that informed decisions can be made about appropriate investment in this approach.