Ecological effects of biodiversity - Wikipedia
These ecological effects of biodiversity in turn are affected by ..
has a less clear importance in community ecology
Ecology and Evolution published by John Wiley & Sons Ltd.AB - Recent investigations have shown that two components of community trait composition are important for key ecosystem processes: (i) the community-weighted mean trait value (CWM), related to the mass ratio hypothesis and dominant trait values in the community, and (ii) functional diversity (FD), related to the complementarity hypothesis and the divergence of trait values.
The vast biodiversity knowledge gap suggests that DNA barcoding applications makes it tempting to consider barcoding data for any onetaxonomic group as valuable information for making predictions about other taxonomic groups. Application of PD to inferred phylogenetic patterns may boost surrogacy in reflecting historical processes and relationships among geographic areas that are shared by many different taxonomic groups. For example, the phylogeny for one taxonomic group may reflect historical processes/relationships among geographic areas that are shared by other taxonomic groups, so that observed differences among areas in PD-complementarity values also reflect the values that would have been calculated for the other groups. Such a surrogacy hypothesis remains largely untested, and requires corroboration assessments (see the section on ).
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A trade-offs perspective based on complementarity suggests that thereis good capacity for balancing different values in setting prioritiesin a given region. Every place has biodiversity, but its contributionto the global option values of biodiversity is indicated by its complementarity value, not its total diversity. It is the comparison of the place's current complementarity value to the other values/opportunities in that place that matters when considering trade-offs at a regional scale. There may be apparent high conflict in a region, in that places with high biodiversity have high values for some other land use opportunity, but in such cases the region maywell be able to satisfy both needs. Trade-offs applications based on complementarity have suggested that other values can be integrated without much penalty to biodiversity goals [an example is A Biodiversity Conservation Plan for Papua New Guinea Based on Biodiversity Trade-offs Analysis in ]. The Millennium Ecosystem Assessment [see ] emphasized trade-offs of this kind to find a balanced provision of the various ecosystem services provided by the world's ecosystems. The assessment also called for further work on developing a calculus of biodiversity, so that these trade-offs approaches could integrate the biodiversity gains from a wide range of conservation instruments (protected areas; payments to private land owners; control of invasive species, etc.)
To further address the mechanisms behind the biodiversity effects in this nitrogen (N)-limited system (), we examine the trends in plant tissue N. This allows us to test the hypothesis that positive complementarity effects are associated with legumes increasing N availability (; ; ; ), and to test for additional mechanisms. Specifically, we test for the effects of four functional groups on the plant N pools, and for the increased efficiency of N use in diverse communities. Increased efficiency of N use in diverse communities is an untested mechanism by which diverse communities may increase productivity. If diverse communities are more competitive, then plants in these communities may have lower tissue N concentrations. Therefore, we test the hypothesis that diverse communities have lower tissue N concentrations (higher biomass: N ratios), which would indicate higher productivity per unit of limiting resource and could partially explain the higher productivity observed at higher diversity.
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Numerous experiments have found a positive relationship between species number and productivity or aboveground biomass in grassland communities (reviewed in ; ; ; , ; ; ; ). however observed no relationship between species number and productivity. These existing studies demonstrate that the short-term net effect of biodiversity is often positive, but that this can be primarily due to either selection or complementarity effects. We suggest that the initial effect of biodiversity may depend upon the relationship between monoculture biomass and relative yield (which determines the selection effect), while the long-term effect of biodiversity may prove to be consistently positive due to complementarity effects. In general, the complementarity effects will increase over time if diverse communities are able to acquire and retain more limiting resource, as found in this experiment.
Corroboration assessment may be an important missing element in this framework. In much the same role it plays for phylogenetic hypotheses, it can allow many different kinds of evidence (suggested by different secondary concepts), all brought to bear on a single species concept. Evidence for a species hypothesis will be some fit of observations to the hypothesis, and corroboration will depend on the improbability of such goodness-of-fit without the hypothesis (Faith and Trueman 2001; Faith, 2004). This supports a unified species concept as something more than just a shifting of the pluralism problem down one level — the inevitable pluralism now properly reflects the various kinds of evidence that may bear on the same concept. There are no a priori restrictions on the formof the evidence for species hypotheses, but assessment of improbability of evidence is important in avoiding an arbitrary, grab-bag, approach. Further, over time, experience in corroboration assessment in different contexts — for example, for different kinds of organisms — may have lessons about the context-dependent pitfalls of certain kinds of evidence. This processwill help evaluate new kinds of evidence, such as that from DNA barcoding, discussed below in the section on .
The term niche differentiation ..
as it applies to the field of ecology, ..
Coexistence of apparently similar species ..
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Spatial Complementarity and the Coexistence of ..
Partitioning Selection and Complementarity in …
The sections above highlighted the role of complementarity — theadditional contribution made by a place (or other entity, such as aspecies) to the overall representation of the hierarchy of variationthat makes up biodiversity. But the true biodiversity complementarityof a place inevitably is unknown and must be estimated using someknown, “surrogate”, information. We may not know enough in a particularcase to consider surrogates that are to reflect a fine scale ofvariation. For example, at a whole country scale, to a firstapproximation all species may be judged equal in comparing biodiversitycontributions of different places. A whole country study may not focusdirectly on variation at the genetic or even species scales, but mightuse ecosystem types or similar as the surrogates to assessrepresentativeness of its protected areas system. If the assessmentreveals that a whole ecosystem type is not represented, then thisdirects priorities for land acquisition. If all types are alreadyrepresented, then variation within these can be the focus, perhaps asindicated by representation of species.
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This example supports the idea that Popperian corroboration for a biodiversity hypothesis arises only if the evidence is judged to be improbable — in spite of attempts to identify background knowledge that suggests that the evidence is probable even without the hypothesis. For biodiversity surrogates, a common hypothesis is that the pattern of species “turnover” over different geographic areas forone taxonomic group will indicate the pattern for all biodiversity. Good evidence for the surrogacy hypothesis is typically claimed when the pattern for the surrogate taxonomic group is congruent with that of some target set of taxa. However, on many occasions such evidence can be explained away as probably arising simply because of a shared bias in the geographic sampling of the surrogate and target taxonomicgroups (for review, see Faith 2003). The evidence based on congruencecan be explained away as a probable result even without the hypothesis. Based on such evidence, corroboration for the surrogacy hypothesis is low.
Tools for the Microbiome: Nano and Beyond - ACS …
JIANG Xiao-Lei, ZHANG Wei-Guo, DUAN Zheng-Hu. EFFECTS OF COMPLEMENTARITY ON DIVERSITY-PRODUCTIVITY RELATIONSHIP. Chinese Journal of Plant Ecology, 2005, 29(4): 523-529.
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