History
The notion that ecosystems' functions can be affected by their constituent parts has its origins in the 19th century.Functional Diversity
Functional diversity is widely considered to be "the value and the range of those species and organismal traits that influence ecosystem functioning" In this sense, the use of the term "function" may apply to individuals, populations, communities, trophic levels, or evolutionary process (i.e. considering the function of adaptations). Functional diversity was conceived as an alternative classification to schemes using genetic diversity or physiological diversity to measure the ecological importance of species in an environment, as well as a way to understand how biodiversity affects specific ecosystem functions, where in this context, 'biodiversity' refers to the diversity of ecosystem functions present in a given system. Understanding ecosystems via functional diversity is as powerful as it is broadly applicable and gives insight into observable patterns in ecosystems, such as species occurrence, species competitive abilities, and the influence of biological communities on ecosystem functioning.Impact on Ecosystem Health
A key interest of modern research in Functional Ecology is the impact of functional diversity on ecosystem health. Unsurprisingly, biodiversity has a positive impact on the productivity of an ecosystem. Increased functional diversity increases both the capacity of the ecosystem to regulate the flux of energy and matter through the environment (Ecosystem Functions) as well as the ecosystem's ability to produce resources beneficial to humans such as air, water, and wood (Ecosystem Services). Ecosystem Functions are drastically reduced with decreases in the diversity of genes, species and functional groups present within an ecosystem. In fact, reductions in functional diversity broadly impact the survivability of organisms in an environment regardless of functional group, trophic level, or species, implying that the organization and interaction of communities in an ecosystem has a profound impact on its ability to function and self-sustain. Furthermore, diversity improves environmental stability. The greater an ecosystem's diversity, the more resilient it is to changes in species composition (e.g. extinction events or invasive species) and extraneous changes to environmental conditions (e.g. logging, farming, and pollution). Moreover, the benefits that diversity provides to an environment scale non-linearly with the amount of diversity. Unfortunately, this relationship also acts in the opposite direction. The ''loss'' of diversity non-linearly disrupts ecosystems (even stable ones); this negative impact is especially detrimental when the loss is across trophic levels. For, example, the loss of a single tertiary predator can have cascading effects on the food chain, resulting in reduction of plant biomass and genetic diversity. This in turn can alter the "vegetation structure, fire frequency, and even disease epidemics in a range of ecosystems". The effects of diversity on ecosystems are so powerful, that they can rival the impact of climate change and other global ecosystem stressors. Alternatively, in rare situations, diversity has been shown to retard ecological productivity. In experimentally concocted microscopic environments, a diverse culture of bacteria was unable to out-produce a homogeneous culture of an 'efficient' control strain. However, the statistical validity and setup of these experiments have been questioned, and require further investigation to carry substantial merit. In general, the current consensus that diversity is beneficial to ecosystem health has much more theoretical and empirical support and is more widely applicable.Scaling
Most models of complex functional diversity are only effective in a small range of spatial scales. However, by defining the functional trait probability density as a "function representing the distribution of probabilities of observing each possible trait value in a givenApplications of Functional Ecology
A functional approach to understanding and dealing with environments provides numerous benefits to our understanding of biology and its applications in our lives. While the concept of functional ecology is still in its infancy, it has been widely applied throughout biological studies to better understand organisms, environments, and their interactions.Species Detection and Classification
The notions of functional ecology have beneficial implications for species detection and classification. When detecting species, ecologically important traits, such as plant height, influence the probability of detection during field surveys. When holistically analyzing an environment, the systematic error of imperfect species detection can lead to incorrect trait-environment evolutionary conclusions as well as poor estimates of functional trait diversity and environmental role. For example, if small species of insects are less likely to be detected, researchers may conclude that they are much more scarce (and thus less impactful) in the environment than larger species of insects. This 'detection filtering' has major consequences on functional packaging and the defining functional groups in an ecosystem. Thankfully, correlations between environmental change and evolutionary adaptation are much larger than the effects of imperfect species detection. Nevertheless, approaching ecosystems with theoretical maps of functional relationships between species and groups can reduce the likelihood of improper detection and improve the robustness of any biological conclusions drawn.Functional traits
A functional approach to defining traits can even help species classification. Trait focused schemes of taxonomy have long been used to classify species, but the number and type of 'trait' to consider is widely debated. Considering more traits in a classification scheme will separate species into more specific functional groups, but may lead to an overestimation of total functional diversity in the environment. However, considering too few traits runs the risk of classifying species as functionally redundant, when they are in fact vital to the health of the ecosystem. So, before one can classify organisms by traits, the definition of 'trait' must be settled. Rather than define traits as proxies for organism performance, as Darwin did, modern ecologists favor a more robust definition of traits often referred to as "functional traits". Under this paradigm, functional traits are defined as morpho-physiophenological traits which impact fitness indirectly via their effects on growth, reproduction and survival. Notice that is definition is not specific to species. Since larger biological organizations grow, reproduce and sustain just as individual organisms do, functional traits can be used to describe ecosystem processes and properties as well. To distinguish between functional traits at different scales, the classification scheme adopts the following nomenclature. Individual organisms have Ecophysiological traits and life-history traits; populations have demographic traits; communities have response traits; and ecosystems have effect traits. At each level, functional traits can directly and indirectly influence functional traits in the levels above or below them. For example, when averaged over an ecosystem, individual plants' heights can contribute to ecosystem productivity or efficiency.Genomics
Functional Ecology is closely intertwined with genomics. Understanding the functional niches that organisms occupy in an ecosystem can provide clues to genetic differences between members of a genus. On the other hand, discovering the traits/functions that genes encode for yields insight into the roles that organisms perform in their environment. This kind of genomic study is referred to as genomic ecology or ecogenomics. Genomic ecology can classify traits on cellular and physiological levels leading to a more refined classification system. In addition, once genetic markers for functional traits in individuals are identified, predictions about the functional diversity and composition of an ecosystem can be made from the genetic data of a few species in a process called "reverse ecology". Reverse ecology can contribute to better taxonomy of organisms as well. Rather than defining species by genetic proximity alone, organisms can be additionally classified by the functions they serve in the same ecology. This application of reverse ecology has proven especially useful in the classification of bacteria. Researchers were able to identify the correspondence between genetic variation and ecological niche function in the genus ''Agrobacterium'' and their greater biological implication on species distinction and diversity in the ecosystem. The researchers found that 196 genes specific to ''Agrobacterium fabrum'' coded for metabolic pathways specific to plants which allowed for the use of plant-specific compounds and sugars to avoid iron deficiency. This trait, unique to ''Agrobacterium fabrum,'' allowed it to avoid competition with closely related bacteria in ''Agrobacterium'' found within the same environment. Thus, understanding the genetics of ''Agrobacterium fabrum'' allowed researchers to infer that it evolved into the niche (i.e. ecological role) of a plant so that it could avoid competing with its close relatives. If this process can be shown to generalize, then the ecological functions of other organisms can be inferred simply from genetic information. However, reverse ecology and genomic ecology face several hurdles before they can be accepted as rigorous and mainstream approaches to taxonomy or ecology. One of the major challenges is that technologies for the sequencing and comparison of transcriptomic data do not exist, making the acquisition of transcriptomic data dependent on environmental conditions. Additionally, as studied environments increase in complexity, transcriptomic data becomes harder to collect. Furthermore, the functions that many discovered genes encode for are still unknown making it difficult if not impossible to infer ecological function from a genome. Testing hypotheses concerning what functions given genes encode for is difficult experimentally and is expensive and time-consuming.De-extinction
Functional ecology also has broad applications to the science of and debate overJournals
The scientific journal '' Functional Ecology'' is published by theSee also
*References
{{modelling ecosystems, expanded=other Subfields of ecology