Data

Data used for analysis and graph

Community Biomass and Bottom up Multivariate Nutrient Complementarity Mediate the Effects of Bioturbator Diversity on Pelagic Production

<div><p>Tests of the biodiversity and ecosystem functioning (BEF) relationship have focused little attention on the importance of interactions between species diversity and other attributes of ecological communities such as community biomass. Moreover, BEF research has been mainly derived from studies measuring a single ecosystem process that often represents resource consumption within a given habitat. Focus on single processes has prevented us from exploring the characteristics of ecosystem processes that can be critical in helping us to identify how novel pathways throughout BEF mechanisms may operate. Here, we investigated whether and how the effects of biodiversity mediated by non-trophic interactions among benthic bioturbator species vary according to community biomass and ecosystem processes. We hypothesized that (1) bioturbator biomass and species richness interact to affect the rates of benthic nutrient regeneration [dissolved inorganic nitrogen (DIN) and total dissolved phosphorus (TDP)] and consequently bacterioplankton production (BP) and that (2) the complementarity effects of diversity will be stronger on BP than on nutrient regeneration because the former represents a more integrative process that can be mediated by multivariate nutrient complementarity. We show that the effects of bioturbator diversity on nutrient regeneration increased BP via multivariate nutrient complementarity. Consistent with our prediction, the complementarity effects were significantly stronger on BP than on DIN and TDP. The effects of the biomass-species richness interaction on complementarity varied among the individual processes, but the aggregated measures of complementarity over all ecosystem processes were significantly higher at the highest community biomass level. Our results suggest that the complementarity effects of biodiversity can be stronger on more integrative ecosystem processes, which integrate subsidiary “simpler” processes, via multivariate complementarity. In addition, reductions in community biomass may decrease the strength of interspecific interactions so that the enhanced effects of biodiversity on ecosystem processes can disappear well before species become extinct.</p> </div

Summary of the factorial (for species richness and biomass) and nested (for species composition) analyses of variance (ANOVA) for nutrient fluxes and bacterioplankton production.

<p>The analyses were performed independently considering invertebrate biomass and invertebrate richness as fixed orthogonal factors, whereas invertebrate species composition was nested under invertebrate species richness irrespective of biomass. Brackets indicate the nesting factor. Bold <i>P</i>-values indicate a statistically significant effect (<i>P</i><0.05).</p

Appendix B. Pearson’s correlations between the coefficients of determination (R²) of the species richness–ecosystem processes regressions and the F values for the nested effects of species composition with the nontransgressive overyielding (Dmax) and transgressive overyielding (DT) values for the four ecosystem processes analyzed in this study.

Pearson’s correlations between the coefficients of determination (R²) of the species richness–ecosystem processes regressions and the F values for the nested effects of species composition with the nontransgressive overyielding (Dmax) and transgressive overyielding (DT) values for the four ecosystem processes analyzed in this study

Isopleths showing changes in bacterial production (BP) as a function of dissolved inorganic nitrogen (DIN) and total dissolved phosphorus (TDP) fluxes in microcosms inhabited by benthic bioturbators.

<p>Isopleths showing changes in bacterial production (BP) as a function of dissolved inorganic nitrogen (DIN) and total dissolved phosphorus (TDP) fluxes in microcosms inhabited by benthic bioturbators.</p

Effects (mean ±1 SE) of invertebrate biomass, species richness and taxonomic composition on (a, d) dissolved inorganic nitrogen (DIN) flux, (b, e) total dissolved phosphorus (TDP) flux and (c, f) bacterioplankton production (BP).

<p>Left-hand panels show the interactive effects of invertebrate biomass and species richness on ecosystem processes. Right-hand panels show the overall effects (irrespective of biomass) of species richness and composition (nested factor) on the magnitude of ecosystem processes analyzed. The overall linear effect of species richness was calculated by regressing ecosystem process data from all individual microcosms (<i>n</i> = 84, controls not included) as a function of species richness across all biomass levels. The overall effects of taxonomic composition are shown by nested comparisons among mean values across all biomass levels for each individual species and 2-species mixtures. Treatments marked with different letters within the same species richness level differ significantly from one another (Tukey test, <i>P</i><0.05). <i>C</i>sp. = <i>Chironomus</i> sp., <i>Hs</i> = <i>Heteromastus similis</i>, <i>Ha</i> = <i>Heleobia australis</i>.</p

Transgressive overyielding for the ecosystem processes analyzed.

<p>Diversity effect sizes (ln response ratios) and their ±95% bootstrapped CI were estimated from the weighted integration, throughout 9999 iterations, of the effect sizes calculated from the proportional response of 2- and 3-species mixtures to their respective best constituent monoculture for each biomass level. Significant overall transgressive overyielding occurs if the value of <i>LR_trans</i> and its confidence interval are greater than zero (dashed line). Abbreviations for ecosystem processes are as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0044925#pone-0044925-g002" target="_blank">figure 2</a>.</p

Appendix A. A list of faunal taxa (excluding bacteria) recorded in four different species of bromeliads at Macaé, RJ, Brazil.

A list of faunal taxa (excluding bacteria) recorded in four different species of bromeliads at Macaé, RJ, Brazil

Correlates of Zooplankton Beta Diversity in Tropical Lake Systems

<div><p>The changes in species composition between habitat patches (beta diversity) are likely related to a number of factors, including environmental heterogeneity, connectivity, disturbance and productivity. Here, we used data from aquatic environments in five Brazilian regions over two years and two seasons (rainy and dry seasons or high and low water level periods in floodplain lakes) in each year to test hypotheses underlying zooplankton beta diversity variation. The regions present different levels of hydrological connectivity, where three regions present lakes that are permanent and connected with the main river, while the water bodies of the other two regions consist of permanent lakes and temporary ponds, with no hydrological connections between them. We tested for relationships between zooplankton beta diversity and environmental heterogeneity, spatial extent, hydrological connectivity, seasonality, disturbance and productivity. Negative relationships were detected between zooplankton beta diversity and both hydrological connectivity and disturbance (periodic dry-outs). Hydrological connectivity is likely to affect beta diversity by facilitating dispersal between habitats. In addition, the harsh environmental filter imposed by disturbance selected for only a small portion of the species from the regional pool that were able to cope with periodic dry-outs (e.g., those with a high production of resting eggs). In summary, this study suggests that faunal exchange and disturbance play important roles in structuring local zooplankton communities.</p></div

Zooplankton beta diversity for each studied region.

<p>(A) Zooplankton beta diversity (as the mean Jaccard distance to group centroid) for each region, sampling time (for each region, the different data points in the X-axis represent the different sampling times) and lake categories (permanent connected, permanent isolated and temporary isolated). (B) Environmental heterogeneity for each region, sampling time and lake categories.</p