Importance Of Functional Diversity Research Articles

Disentangling multiple relationships of species diversity, functional diversity, diatom community biomass and environmental variables in a mountainous watershed

Biodiversity and ecosystem functioning (BEF) relationships are important research issues in the context of biodiversity loss. However, most studies only explored BEF relationships using species richness as a proxy for biodiversity without considering the effects of species evenness and importance of functional diversity on ecosystem functioning. In the present study, we explored multiple relationships among in-stream environmental variables, species diversity (species richness and species evenness), functional diversity (functional richness, functional evenness and Rao’s quadratic entropy index) and biomass of benthic diatom communities from a Chinese mountainous river network. We tested two hypotheses: (1) species richness and evenness affect community biomass independently, and (2) species diversity directly affects community biomass and also indirectly affects community biomass by influencing functional diversity. We found that benthic diatom diversity and biomass were influenced by wetted width, conductivity, and pH. Species richness and evenness had positive and negative effects on community biomass, respectively; while, the effect of richness (with a pathway coefficient of 0.39) was stronger than that of evenness (−0.28). However, we have not found an interaction pathway between species richness and species evenness in structural equation models, indicating that the two effects on community biomass were independent of each other. Both functional richness and Rao’s quadratic entropy index had positive effects on community biomass, although effects of other variables blurred the relationship between functional richness and community biomass in structural equation modeling. Besides direct effects, species diversity also indirectly affected community biomass through influencing Rao’s quadratic entropy index, with direct effects (0.27) were more than twice stronger than indirect effects (0.12). Our findings imply that the selection effect played a dominant role in the relationship between diatom diversity and biomass, indicated by the negative species evenness and biomass relationship; meanwhile, the complementarity effect was also important. The inclusion of more diversity indices to explore the biodiversity-biomass relationship would help to provide a deeper and more comprehensive understanding of this relationship and its driving mechanisms. We suggest carrying out more studies on BEF relationships in streams and rivers to support protection practices for sustaining biodiversity and their ecosystem functions in natural lotic ecosystems.

The importance of functional diversity in regulating forage biomass and nutrition: evidence from mowing in semiarid grasslands

Mowing removes plant photosynthetic organs, thus decreasing plant biomass and nutrients in the community. Responses of community functional diversity, biomass, and nutrient status to mowing play a crucial role in the restoration and sustainable use of degraded grasslands, but have not been well studied. Our study linked functional diversity with forage biomass and nutrition in a semiarid grassland. We found that annual mowing reduced community biomass, in particular significantly reduced the dominant plants biomass, which was maintained with biennial mowing. In addition, this study showed that functional diversity could be maintained at a high level under biennial mowing compared to unmowed, but significantly decreased under annual mowing. Structural equation modeling indicated that annual mowing reduced dominant plants biomass by reducing community functional diversity. Mowing decreased dominant plants nutrients by decreasing community functional diversity and soil nutrients, but had no significant effect on nutrients of community and nondominant plants. Furthermore, there was a strong positive correlation between community functional diversity with forage production and nutrition. In conclusion, our study demonstrated that biennial mowing increases community biomass, litter mass, and dominant plant nutrition by regulating functional diversity. Therefore, biennial mowing can provide better conservation of grassland ecosystems and is a suitable grassland management practice in semiarid grasslands.

Monitoring Plant Functional Diversity Using the Reflectance and Echo from Space

Plant functional diversity (FD) is an important component of biodiversity. Evidence shows that FD strongly determines ecosystem functioning and stability and also regulates various ecosystem services that underpin human well-being. Given the importance of FD, it is critical to monitor its variations in an explicit manner across space and time, a highly demanding task that cannot be resolved solely by field data. Today, high hopes are placed on satellite-based observations to complement field plot data. The promise is that multiscale monitoring of plant FD, ecosystem functioning, and their services is now possible at global scales in near real-time. However, non-trivial scale challenges remain to be overcome before plant ecology can capitalize on the latest advances in Earth Observation (EO). Here, we articulate the existing scale challenges in linking field and satellite data and further elaborated in detail how to address these challenges via the latest innovations in optical and radar sensor technologies and image analysis algorithms. Addressing these challenges not only requires novel remote sensing theories and algorithms but also urges more effective communication between remote sensing scientists and field ecologists to foster mutual understanding of the existing challenges. Only through a collaborative approach can we achieve the global plant functional diversity monitoring goal.

Importance of functional diversity in assessing the recovery of the microbial community after the Hebei Spirit oil spill in Korea

Over 10 years after the Hebei Spirit oil spill (HSOS), the concentrations of pollutants, such as TPH and PAHs, in spilled crude oil have recovered to background levels, but in some areas, the environment has not fully recovered. In particular, PAHs were more resistant to degradation, and their persistence could have deleterious impacts on the sediment ecosystem. This study aimed to evaluate the microbial recovery of coastal sediments from the HSOS by analyzing the structure and diversity of the microbial community and its functional contribution to PAHs degradation. High-throughput sequencing on the MiSeq platform was conducted using tidal flat sediments collected in 2014 and 2016 from the area contaminated by the HSOS. The microbial recovery was evaluated by various diversity factors, including microbial composition and structure and functional diversity based on PICRUSt analysis. The abundance of microbial taxa associated with TPH degradation was higher in 2014 than that in 2016, but the taxa associated with PAHs degradation were similar between years. These results are consistent with the dynamics of microbes associated with the fate of pollutants, and they also showed similar tendency in functional profiles. That is, even if the pollutants are completely degraded, the microbial community has not yet completely recovered from the HSOS. The evaluation of microbial ecosystems in contaminated environments should consider both the fate of pollutants and the dynamics of microbial species that make functional contributions to the degradation of pollutants.

Evidence that emergent Nothofagus dombeyi do not depress carbon sequestration rates of canopy species in an old-growth Chilean temperate forest

ABSTRACTThe influence of functional diversity on ecosystem productivity has practical implications for the carbon sequestration potential of forest ecosystems. Vertical stratification may be one key aspect of functional diversity that influences stand productivity through differential resource use. Although additive basal area of canopy and emergent species has been reported in some forests, it is unclear whether this represents significant additive productivity, or mainly a reflection of the great longevity of the emergent trees. We asked if the presence of emergent Nothofagus dombeyi influences carbon sequestration in wood of the associated canopy species in an old-growth temperate forest in south-central Chile, the canopy species all being more shade-tolerant than N. dombeyi. We estimated wood volume increment of all trees on four pairs of plots in old-growth stands in Parque Nacional Puyehue, each pair consisting of one 25×25 m plot with emergent trees and another lacking emergents. Heights and diameters of all trees were measured, and increment cores were extracted to permit back-estimation of the same variables 2 years earlier. Published data on density and carbon content of wood were then used to convert wood volume production to carbon sequestration rates. Rates of carbon sequestration in wood of the canopy species were very similar on plots with and without N. dombeyi, showing that productivity of the emergent trees was additive to that of the canopy species. As a result, the average total carbon sequestration rate of plots with emergents was nearly twice that of plots lacking emergents (2.8 versus 1.5 T C ha−1 yr−1). The occurrence of additive productivity highlights the importance of functional diversity and vertical stratification for forest management and carbon sequestration. Conservation of vertical stratification is desirable when complementary light-use characteristics of the dominant species optimise carbon sequestration.

The importance of functional diversity in the stability of Mediterranean shrubland communities after the impact of extreme climatic events

13 paginas.-- 5 figuras.-- 1 tabla.-- referencias.-- Supplementary material is available at Journal of Plant Ecology online. https://doi.org/10.1093/jpe/rtw027

Functional dissimilarity across trophic levels as a driver of soil processes in a Mediterranean decomposer system exposed to two moisture levels

The role of biodiversity for soil processes remains poorly understood. Existing evidence suggests that functional diversity rather than species richness is relevant for soil functioning. However, the importance of functional diversity has rarely been assessed simultaneously at more than one trophic level, critically limiting the prediction of consequences of biodiversity loss for soil functioning. In a laboratory microcosm experiment, we tested the hypothesis that increasing functional dissimilarity of both litter‐feeding soil fauna and litter mixtures interactively affects the rates of five different soil processes related to litter decomposition. We created trait‐based functional dissimilarity gradients using five assemblages of two detritivore species and five mixtures of two plant litter species commonly found in Mediterranean shrubland ecosystems of southern France. With increasing drought periods predicted for Mediterranean ecosystems in the future, we additionally included two different watering frequencies to evaluate the impact of drought on soil processes and how drought interacts with functional dissimilarity. The different fauna assemblages and litter mixtures showed strong effects on litter mass loss, soil organic carbon and nitrogen leaching, as well as on soil microbial activities. Up to 20% of the variation in response variables was explained by functional dissimilarity, suggesting an ecologically relevant impact of functional diversity on soil process rates. Detritivore functional dissimilarity tended to have stronger effects when combined with increasingly dissimilar litter mixtures, suggesting that trait dissimilarity interacts across trophic levels. Drought affected several soil processes but did not modify the relationships between functional dissimilarity and process rates. Our results indicate that trait diversity of detritivore assemblages and litter mixtures is an important predictor of soil process rates. The common and easily measurable traits used in our study suggest straightforward application across different types of ecosystems and environmental conditions.

Termite Mounds Increase Functional Diversity of Woody Plants in African Savannas

Fine-scale spatial heterogeneity influences biodiversity and ecosystem productivity at many scales. In savanna systems, Macrotermes termites, through forming spatially explicit mounds with unique woody plant assemblages, emerge as important sources of such heterogeneity. Despite a growing consensus regarding the importance of functional diversity (FD) to ecosystem processes, no study has quantified how termite mounds affect woody plant FD. We address whether termite mounds alter the distribution of functional traits, and increase FD of woody plant communities within Africa’s largest savanna woodland, the 2.7 million km2 miombo system. Using plant traits that change according to soil resources (for example, water and nutrients), and disturbance (for example, fire and elephant herbivory), we identified response functional groups and compared relative representation of these groups between mound and matrix habitats. We also asked whether mound and matrix habitats differed in their contribution to FD within the system. Although species representing most functional groups were found in both mound and matrix habitats, relative abundance of functional groups differed between mound and matrix. Mound plant assemblages had greater response diversity to soil resources than matrix plots, but there was no difference in response diversity to disturbance. High trait values on mounds included tree height, leaf nitrogen, phosphorus, and palatability. Species with root ectomycorrhizae dominated the matrix. In conclusion, these small patches of nutrient-enriched substrate emerge as drivers of FD in above-ground woody plant communities.

Original Articles: Plant Attribute Diversity, Resilience, and Ecosystem Function: The Nature and Significance of Dominant and Minor Species

This study tested an hypothesis concerning patterns in species abundance in ecological communities. Why do the majority of species occur in low abundance, with just a few making up the bulk of the biomass? We propose that many of the minor species are analogues of the dominants in terms of the ecosystem functions they perform, but differ in terms of their capabilities to respond to environmental stresses and disturbance. They thereby confer resilience on the community with respect to ecosystem function. Under changing conditions, ecosystem function is maintained when dominants decline or are lost because functionally equivalent minor species are able to substitute for them. We have tested this hypothesis with respect to ecosystem functions relating to global change. In particular, we identified five plant functional attributes— height, biomass, specific leaf area, longevity, and leaf litter quality—that determine carbon and water fluxes. We assigned values for these functional attributes to each of the graminoid species in a lightly grazed site and in a heavily grazed site in an Australian rangeland. Our resilience proposition was cast in the form of three specific hypotheses in relation to expected similarities and dissimilarities between dominant and minor species, within and between sites. Functional similarity—or ecological distance—was determined as the euclidean distance between species in functional attribute space. The analyses provide evidence in support of the resilience hypothesis. Specifically, within the lightly grazed community, dominant species were functionally more dissimilar to one another, and functionally similar species more widely separated in abundance rank, than would be expected on the basis of average ecological distances in the community. Between communities, depending on the test used, two of three, or three of four minor species in the lightly grazed community that were predicted to increase in the heavily grazed community did in fact do so. Although there has been emphasis on the importance of functional diversity in supporting the flow of ecosystem goods and services, the evidence from this study indicates that functional similarity (between dominant and minor species, and among minor species) may be equally important in ensuring persistence (resilience) of ecosystem function under changing environmental conditions.

Expression, purification, and characterization of protein kinase C-epsilon.

Of the recently described members of the protein kinase C (PKC) family (-delta, -epsilon, -zeta), no detailed properties of the purified enzymes have been presented. Here we describe the expression of PKC-epsilon in insect cells using a baculovirus vector. The recombinant enzyme has been purified to homogeneity by sequential chromatography on DEAE-cellulose, serine-Sepharose, Mono Q, and Superose 12; the protein shows a molecular mass of 90 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. PKC-epsilon is dependent upon phospholipid and diacylglycerol (or phorbol esters) for activity and displays a pattern of specificity for these effectors similar to other PKC isotypes. Similarly, inhibition of PKC-epsilon by staurosporine and H-7 parallels inhibition of other PKC isotypes. However, unlike PKC-alpha, -beta, and -gamma, PKC-epsilon shows no dependence upon Ca2+. Furthermore, the substrate specificity of PKC-epsilon is quite different from other characterized PKCs. The importance of functional diversity within the PKC family is discussed.