Biological Trait Analysis
This article should be read in conjunction with the articles Functional groups, Functional traits and Biodiversity, ecosystem functioning and ecosystem function.
Biological Trait Analysis (BTA) describes ecological communities using characteristics of the organisms they contain, such as body size, longevity, mobility, feeding mode and reproductive strategy, rather than only their taxonomic identity[1]. These characteristics, or biological traits, can indicate how organisms respond to environmental conditions and how they contribute to ecological processes.
Contents
Aim of Biological Trait Analysis (BTA)
BTA provides a method to describe the functional composition of a community from the traits represented by its species[2]. Biological traits are properties of individual organisms and include morphological, physiological, life-history and behavioral characteristics such as body size, longevity, mobility, feeding mode and reproductive strategy[3].
Communities with different species can be functionally similar if their species share similar traits, while communities with similar numbers of species can differ strongly in functional characteristics. BTA can therefore be used to assess functional diversity, but it can also identify which particular traits dominate or change along environmental gradients. Functional diversity describes the variety and distribution of functional characteristics within the community and is therefore only one aspect that can be derived from BTA.
The trait composition revealed by BTA can provide information on the potential functioning of ecological communities and, where relevant response traits are included, on their sensitivity or resilience to environmental change. BTA does not measure ecosystem processes such as productivity, nutrient cycling or sediment mixing directly, but can help infer how changes in community composition may affect these processes.
Traits used in BTA are commonly distinguished as response traits and effect traits[4][2][5]. Response traits influence how organisms respond to environmental conditions or disturbance, whereas effect traits influence ecosystem processes. Some traits can have both roles, depending on the ecological question.
Biological Trait Analysis differs from conventional taxonomic measures of biodiversity. Taxonomic analyses distinguish communities according to the species present and their relative abundance, whereas BTA describes communities according to the traits represented by those species. It can therefore reveal functional similarities or differences between communities that are not apparent from taxonomic composition alone [6].
Performing Biological Trait Analysis
A BTA generally combines a 'species-by-site matrix', containing the abundance, biomass or occurrence of species, with a 'species-by-trait matrix' describing the traits of those species[1].
Traits are usually divided into categories, often termed 'modalities'. For example, feeding mode can include suspension feeding, deposit feeding, grazing and predation, while mobility can range from sessile to highly mobile. Because organisms do not always belong exclusively to a single category, BTA often uses 'fuzzy coding', in which a species can be assigned affinities to several modalities of the same trait[1].
The trait scores are combined with species abundance or biomass to determine the relative representation of the different traits in each assemblage. Multivariate statistical methods can then be used to identify patterns in trait composition among sites or along environmental gradients[1].
Environmental conditions and biological traits
An important theoretical basis for BTA is 'habitat template theory', which proposes that environmental conditions favor organisms whose traits enable them to colonize, survive and reproduce under those conditions[7]. Community trait composition therefore reflects environmental conditions and disturbance history. Response traits can consequently provide information on how communities react to pressures such as physical disturbance, pollution or habitat modification. For example, frequent disturbance may favor small, mobile and rapidly reproducing organisms over large, long-lived species with slow recovery[2].
Effect traits provide complementary information on the potential consequences of community change for ecosystem processes. In benthic communities, for example, feeding mode, burrowing depth, sediment reworking and bio-irrigation can influence nutrient cycling, sediment mixing and benthic-pelagic exchange[5].
Changes in response traits should, however, not automatically be interpreted as changes in ecosystem functioning. Such conclusions require traits that are actually related to the ecosystem processes under consideration[5].
Applications and limitations
Biological Trait Analysis has been widely applied to investigate how environmental pressures such as disturbance, pollution, fishing and habitat change alter the functional composition and functional diversity of ecological communities[8][2].
The outcome of BTA depends on the traits selected. Traits should therefore be chosen according to the ecological question: traits used to assess sensitivity to disturbance are not necessarily the traits most informative about ecosystem processes[5].
Comparisons among studies can also be complicated by differences in trait terminology, definitions and classification schemes. Recent reviews therefore emphasize standardization and transparent reporting of trait definitions and coding[9].
BTA thus complements taxonomic analysis. Taxonomic data show 'which species are present and how their abundances change', whereas BTA helps reveal 'which functional characteristics change and what these changes may imply for ecosystem functioning'.
References
- ↑ 1.0 1.1 1.2 1.3 Bremner, J., Rogers, S.I. and Frid, C.L.J. 2006. Methods for describing ecological functioning of marine benthic assemblages using Biological Trait Analysis (BTA). Ecological Indicators 6: 609–622. Cite error: Invalid
<ref>tag; name "Bremner06" defined multiple times with different content - ↑ 2.0 2.1 2.2 2.3 De Juan, S., Bremner, J., Hewitt, J., Törnroos, A., Mangano, M.C., Thrush, S. et al. 2022. Biological traits approaches in benthic marine ecology: Dead ends and new paths. Ecology and Evolution 12: e9001.
- ↑ Violle, C., Navas, M-L., Vile, D., Kazakou, E., Fortunel, V., Hummel, I. and Garnier, E. 2007. Let the concept of trait be functional! Oikos 116: 882–892
- ↑ Lavorel, S. and Garnier, E. 2002. Predicting changes in community composition and ecosystem function from plant traits: revisiting the Holy Grail. Func. Ecol. 16: 545–556
- ↑ 5.0 5.1 5.2 5.3 Beauchard, O. 2023. The importance of trait selection on the meaning of functional diversity in benthic studies. Frontiers in Marine Science 10: 1195595.
- ↑ Nemani, S., Bowden, D.A., Rowden, A.A., Clark, M.R. and Probert, P.K. 2024. Incorporating functional traits with habitat maps: patterns of benthic functional diversity across spatial scales. Frontiers in Marine Science 11: 1141737.
- ↑ Southwood, T.R.E. 1977. Habitat, the templet for ecological strategies? Journal of Animal Ecology 46: 337-365.
- ↑ Bremner, J. 2008. Species' traits and ecological functioning in marine conservation and management. Journal of Experimental Marine Biology and Ecology 366: 37–47.
- ↑ Susini, I., Tillin, H.M., Anderson, L., Robertson, C.M., Rees, S. and Howell, K.L. 2025. Towards greater standardization in benthic trait research to support application to environmental management. Ecology and Evolution 15: e71072.
Related articles
- Functional groups
- Functional traits
- Functional diversity
- Measurements of biodiversity
- Marine Biodiversity
- Biodiversity, ecosystem functioning and ecosystem function
- Disturbances, biodiversity changes and ecosystem stability
- Ecological niche
References
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