Diversity of habitats and bacterial communities support landscape-scale multifunctionality differently across seasons
- Published
- Accepted
- Subject Areas
- Biodiversity, Ecology, Ecosystem Science, Environmental Sciences, Marine Biology
- Keywords
- Biodiversity, Structural equation modelling, Sediment habitats, Ecosystem functioning
- Copyright
- © 2016 Alsterberg et al.
- Licence
- This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ Preprints) and either DOI or URL of the article must be cited.
- Cite this article
- 2016. Diversity of habitats and bacterial communities support landscape-scale multifunctionality differently across seasons. PeerJ Preprints 4:e2036v1 https://doi.org/10.7287/peerj.preprints.2036v1
Abstract
In this study, we demonstrate how changes in the diversity of habitat and bacterial communities affect landscape multifunctionality. Habitat diversity may beget species diversity by increasing niche availability and resource complementarity. Species diversity, in turn, generally promotes multifunctionality, i.e. the simultaneous performance of multiple ecosystem functions. However, the relationship between habitat diversity and functioning remains to be explicitly explored. In order to test the relationship between habitat diversity and multifunctionality we constructed experimental landscapes of four different habitats common in shallow-water sediment ecosystems: cyanobacterial mats, Ruppia maritima meadows, silty mud and sandy beach. We manipulated the diversity of these habitats over three consecutive seasons and measured bacterial diversity, benthic microalgal diversity and four functions related to marine nitrogen cycling (gross primary production, nitrogen fixation, denitrification and uptake of dissolved inorganic nitrogen). Our results showed that higher habitat and bacterial diversity, but not benthic microalgal diversity, increased landscape multifunctionality. However, the relative importance of habitat and bacterial diversity varied with season. Habitat diversity was generally the strongest driver, affecting multifunctionality directly in summer and indirectly via bacterial diversity in autumn. In spring, neither of the two aspects of diversity was important. Our study demonstrates the importance of considering temporal differences in both habitat and species diversity for landscape multifunctionality, and the importance of direct and indirect effects in mediating ecosystem functions. Habitat homogenization in concert with loss in biodiversity can thus be a driving force of declining ecosystem functioning and the services they underpin.
Author Comment
This is a preprint submission to PeerJ Preprints
Supplemental Information
Table S1: Linear model of bacterial diversity ~ habitat diversity × season
Table S2: Linear model of microalgal diversity ~ habitat diversity × season
Table S3: Linear model of multifunctionality ~ habitat diversity × season
Table S4: Linear model of multifunctionality ~ bacterial diversity × season
Table S5: Linear model of multifunctionality ~ algal diversity × season
Table S6: Standardized total, direct and indirect effects for the group spring
‘Total effects’ are the sum of all direct and indirect effects. ‘Direct effects’ are the direct effects of one variable to another variable and ‘Indirect effects’ are sum of all products affecting one variable (e.g., the indirect effect of Habitat diversity on Multifunctionality is the product of the path between Habitat diversity à Bacterial diversity, and Bacterial diversity à Multifunctionality).
Table S7: Standardized total, direct and indirect effects for the group summer
‘Total effects’ are the sum of all direct and indirect effects. ‘Direct effects’ are the direct effects of one variable to another variable and ‘Indirect effects’ are sum of all products affecting one variable (e.g., the indirect effect of Habitat diversity on Multifunctionality is the product of the path between Habitat diversity à Bacterial diversity, and Bacterial diversity à Multifunctionality).
Table S8: Standardized total, direct and indirect effects for the group autumn
‘Total effects’ are the sum of all direct and indirect effects. ‘Direct effects’ are the direct effects of one variable to another variable and ‘Indirect effects’ are sum of all products affecting one variable (e.g., the indirect effect of Habitat diversity on Multifunctionality is the product of the path between Habitat diversity à Bacterial diversity, and Bacterial diversity à Multifunctionality).
Table S9: Linear model of GPP ~ habitat diversity × season
Table S10: Linear model of N2 fixation ~ habitat diversity × season
Table S11: Linear model of DIN uptake ~ habitat diversity × season
Table S12: Linear model of Denitrification ~ habitat diversity × season
Table S13: <!--[if !supportAnnotations]--> <!--[endif]--> Environmental data for each habitat during summer
PW DIN, total concentration of NH4+, NO3-+NO2- in the pore water (μM). Percent dry weight of total nitrogen (N tot) and organic carbon (C org) in the sediment. Porosity, water content in sediment (%). Density, density of sediment. Chl b, concentration of sediment chlorophyll b (mg m-2). Echi, concentration of sediment echinenone (mg m-2). Fuco, concentration of sediment fucoxanthin (mg m-2). Ruppia, dry weight of Ruppia maritima (mg m-2).
Table S14: Environmental data for each habitat during spring
PW DIN, total concentration of NH4+, NO3-+NO2- in the pore water (μM). Percent dry weight of total nitrogen (N tot) and organic carbon (C org) in the sediment. Porosity, water content in sediment (%). Density, density of sediment. Chl b, concentration of sediment chlorophyll b (mg m-2). Echi, concentration of sediment echinenone (mg m-2). Fuco, concentration of sediment fucoxanthin (mg m-2). Ruppia, dry weight of Ruppia maritima (mg m-2).
Table S15: Environmental data for each habitat during autumn
PW DIN, total concentration of NH4+, NO3-+NO2- in the pore water (μM). Percent dry weight of total nitrogen (N tot) and organic carbon (C org) in the sediment. Porosity, water content in sediment (%). Density, density of sediment. Chl b, concentration of sediment chlorophyll b (mg m-2). Echi, concentration of sediment echinenone (mg m-2). Fuco, concentration of sediment fucoxanthin (mg m-2). Ruppia, dry weight of Ruppia maritima (mg m-2).
Figure 1S
Pictures describing the experimental design used to manipulate the diversity of habitats within landscapes. The habitats ‘Sandy beach’, ‘Silty mud’, ‘Cyanobacterial mats’ and ‘Ruppia meadows’ were collected from shallow-water sediment ecosystems by sampling intact cores in the field and then arrange them randomly into landscapes to form a diversity gradient including one, two, three, and four habitat types. Each replicate landscape was placed in a greenhouse with continuous water flow of coastal surface water.
Figure 2S
Bacterial diversity for each individual habitat (habitat diversity = 1; ‘Sandy beach’, ‘Silty mud’, ‘Cyanobacterial mats’ and ‘Ruppia sp. meadows’) and for each habitat diversity combination, i.e. habitat diversity 2 – 4 expressed as effective phylogenetic diversity of order q = 1 during spring, summer and autumn, n = 84.
Figure 3S
Benthic microalgal diversity (effective number of taxa) for each individual habitat (habitat diversity = 1, ‘Sandy beach’, ‘Silty mud’, ‘Cyanobacterial mats’ and ‘Ruppia sp. meadows’) and for each habitat diversity combination, i.e. habitat diversity 2 – 4 during spring, summer and autumn, n = 42.
Figure 4S
Linear function of relationships between habitat diversity and benthic microalgal diversity (effective number of taxa) during spring, summer and autumn. Shaded areas indicate ± 95% confidence interval, n = 42.
Figure 5S
Linear models of individual functions used to calculate multifunctionality against habitat diversity during spring, summer and autumn. A) Gross Primary Production (mmol O2 m-2 day-1), B) nitrogen fixation (mmol m-2 day-1), C) DIN, dissolved inorganic nitrogen (ammonium and nitrate + nitrite) (mmol m-2 day-1), and D) denitrification (nmol N g wet sed-1 h-1). Shaded areas indicate ±95% confidence interval, n = 84.
Figure 6S
The net habitat diversity effect on landscape multifunctionality in the treatments with all four habitat types. ‘Expected’ is the expected multifunctionality in the treatment based on each of the single habitats and ‘observed’ is the observed multifunctionality. The points are slightly spread on the x-axis (grouped by season) and jittered (within season) for clarity. The triangles represent group means.
Figure 7S
Light intensity (PAR; photosynthetically active radiation) at the research station where the experiments was performed and recorded surface water temperatures in the nearby shallow bay where water was collected for the flow-through system and. The timing of each performed experiment is indicated as ‘spring’, ‘summer’ and ‘autumn’.
Figure 8S
Concentrations of inorganic nutrients (ammonium, nitrate+nitrite and phosphate) in the inflowing water supporting the flow-through system during spring, summer and autumn, n = 168.
Figure 9S
Percent dry weight of organic content in the sediment habitats. A) total nitrogen and B) organic carbon in the sediment of the four habitat types ‘Sandy beach’, ‘Silty mud’, ‘Cyanobacterial mats’ and ‘Ruppia sp. meadows’ during spring, summer and autumn, n = 48.