Alpha and beta diversity of plants and animals along a tropical land-use gradient

Assessing the overall biological diversity of tropical rain forests is a seemingly insurmountable task for ecologists. Therefore, researchers frequently sample selected taxa that they believe reflect general biodiversity patterns. Usually, these studies focus on the congruence of α diversity (the number of species found per sampling unit) between taxa rather than on β diversity (turnover of species assemblages between sampling units). Such approaches ignore the potential role of habitat heterogeneity that, depending on the taxonomic group considered, can greatly enhance β diversity at local and landscape scales. We compared α and β diversity of four plant groups (trees, lianas, terrestrial herbs, epiphytic liverworts) and eight animal groups (birds, butterflies, lower canopy ants, lower canopy beetles, dung beetles, bees, wasps, and the parasitoids of the latter two) at 15 sites in Sulawesi, Indonesia, that represented natural rain forest and three types of cacao agroforests differing in management intensity. In total, we recorded 863 species. Patterns of species richness per study site varied strongly between taxonomic groups. Only 13–17% of the variance in species richness of one taxonomic group could be predicted from the species richness of another, and on average 12–18% of the variance of β diversity of a given group was predicted by that in other groups, although some taxon pairs had higher values (up to 76% for wasps and their parasitoids). The degree of congruence of patterns of α diversity was not influenced by sampling completeness, whereas the indicator value for β diversity improved when using a similarity index that accounts for incomplete sampling. The indication potential of α diversity for β diversity and vice versa was limited within taxa (7–20%) and virtually nil between them (0–4%). We conclude that different taxa can have largely independent patterns of α diversity and that patterns of β diversity can be more congruent. Thus, conservation plans on a landscape scale need to put more emphasis on the high heterogeneity of agroforests and the overarching role of β diversity shaping overall diversity patterns

Can joint carbon and biodiversity management in tropical agroforestry landscapes be optimized?

Managing ecosystems for carbon storage may also benefit biodiversity conservation, but such a potential 'win-win' scenario has not yet been assessed for tropical agroforestry landscapes. We measured above- and below-ground carbon stocks as well as the species richness of four groups of plants and eight of animals on 14 representative plots in Sulawesi, Indonesia, ranging from natural rainforest to cacao agroforests that have replaced former natural forest. The conversion of natural forests with carbon stocks of 227-362 Mg C ha(-1) to agroforests with 82-211 Mg C ha(-1) showed no relationships to overall biodiversity but led to a significant loss of forest-related species richness. We conclude that the conservation of the forest-related biodiversity, and to a lesser degree of carbon stocks, mainly depends on the preservation of natural forest habitats. In the three most carbon-rich agroforestry systems, carbon stocks were about 60% of those of natural forest, suggesting that 1.6 ha of optimally managed agroforest can contribute to the conservation of carbon stocks as much as 1 ha of natural forest. However, agroforestry systems had comparatively low biodiversity, and we found no evidence for a tight link between carbon storage and biodiversity. Yet, potential win-win agroforestry management solutions include combining high shade-tree quality which favours biodiversity with cacao-yield adapted shade levels

Appendix B. Linear and Mantel correlations between study groups.

Linear and Mantel correlations between study groups

Appendix A. An example of the calculation of the six different diversity parameters used in the study.

An example of the calculation of the six different diversity parameters used in the study

Results of Wilcoxon’s tests for matched pairs, comparing (a) the linear correlation (r-)values of the species richness of various study groups against tree species richness with (b) the r-values of the species richness of the same study groups against the species richness of natural forest trees, either in all study plots (upper half of the table) or only in the agroforest study plots (lower half).

<p>W  =  test statistic, P  =  probability.</p

Carbon stocks in natural rainforests and cacao agroforests of varying tree density and shade levels.

<p>Shade levels were defined as: high shade: cacao agroforests with diverse, natural shade trees, retained after thinning of the previous forest cover, underplanted with cacao trees and few fruit trees; medium shade: cacao agroforests with shade tree stands dominated by various species of planted fruit and timber trees; low shade: cacao agroforests with a low diversity of planted shade trees, predominantly non-indigenous, nitrogen-fixing leguminous trees and a few native fruit tree species. Columns show mean carbon stocks (+1 SD) in the above-ground (AG) and below-ground (BG) plant components as well as in the soil. Also shown is the mean stem density (+1 SD) of trees with diameters ≥10 cm at breast height.</p

Efficacy and safety of tenecteplase in combination with enoxaparin, abciximab, or unfractionated heparin: The ASSENT-3 randomised trial in acute myocardial infarction

Background: Current fibrinolytic therapies fail to achieve optimum reperfusion in many patients. Low-molecular-weight heparins and platelet glycoprotein IIb/IIIa inhibitors have shown the potential to improve pharmacological reperfusion therapy. We did a randomised, open-label trial to compare the efficacy and safety of tenecteplase plus enoxaparin or abciximab, with that of tenecteplase plus weight-adjusted unfractionated heparin in patients with acute myocardial infarction. Methods: 6095 patients with acute myocardial infarction of less than 6 h were randomly assigned one of three regimens: full-dose tenecteplase and enoxaparin for a maximum of 7 days (enoxaparin group; n=2040), half-dose tenecteplase with weight-adjusted low-dose unfractionated heparin and a 12-h infusion of abciximab (abciximab group; n=2017), or full-dose tenecteplase with weight-adjusted unfractionated heparin for 48 h (unfractionated heparin group; n=2038). The primary endpoints were the composites of 30-day mortality, in-hospital reinfarction, or in-hospital refractory ischaemia (efficacy endpoint), and the above endpoint plus in-hospital intracranial haemorrhage or in-hospital major bleeding complications (efficacy plus safety endpoint). Analysis was by intention to treat. Findings: There were significantly fewer efficacy endpoints in the enoxaparin and abciximab groups than in the unfractionated heparin group: 233/2037 (11.4%) versus 315/2038 (15.4%; relative risk 0.74 [95% CI 0.63-0.87], p=0.0002) for enoxaparin, and 223/2017 (11.1%) versus 315/2038 (15.4%; 0.72 [0.61-0.84], p&lt;0.0001) for abciximab. The same was true for the efficacy plus safety endpoint: 280/2037 (13.7%) versus 347/2036 (17.0%; 0.81 [0.70-0.93], p=0.0037) for enoxaparin, and 287/2016 (14.2%) versus 347/2036 (17.0%; 0.84 [0.72-0.96], p=0.01416) for abciximab. Interpretation: The tenecteplase plus enoxaparin or abciximab regimens studied here reduce the frequency of ischaemic complications of an acute myocardial infarction. In light of its ease of administration, tenecteplase plus enoxaparin seems to be an attractive alternative reperfusion regimen that warrants further study