Dimensionality of Biodiversity

by

Carlos Henrique Libório, Gisele Moreira dos Santos

• LAST MODIFIED: 12 January 2023
• DOI: 10.1093/obo/9780199830060-0240

Introduction

Although biodiversity is multidimensional, analyses of biodiversity variation were, for a long time, based only on metrics that reflect the number of taxa and the distribution of relative abundance among these taxa. However, in recent decades, functional, genetic, and phylogenetic diversity indices have been used to describe the variation in biodiversity in a complementary way. Diversity metrics have been formulated to understand this multifaceted phenomenon for conservation purposes and assessment of ecosystem processes. Diversity metrics capture the variation in the dimensions of biodiversity, although they also tend to lead to a subdivision of the diversity, affecting the holistic concept of biodiversity. One way to solve this confusion is the use of the dimensionality approach. An analysis of the dimensionality of biodiversity (i.e., number of complementary components of biodiversity represented by measures of diversity) can help in understanding which dimensions best represent biodiversity in a set of diversity measures and the reasons why different diversity metrics may be weak or strongly correlated. The dimensionality of biodiversity refers to the number of diversity measures and their respective importance necessary to assess biodiversity (i.e., the number of orthogonal axes). To that end, a unified way of analyzing all dimensions necessary for an effective understanding of biodiversity has recently been proposed (see General Overviews). This new way of analyzing the different aspects of biodiversity can improve our understanding of how ecological and evolutionary processes shape biodiversity.

General Overviews

The first ideas about the variation of biodiversity metrics, especially taxonomic diversity, date back to the seventies with the seminal article Whittaker 1972. This work presents the basic metrics of biodiversity, such as richness, evenness, Shannon and Simpson index, and how each of them can contribute to community structuring. The relationships between these measures are well described in Ricotta 2005. In recent years, studies that investigate dimensionality have received attention as potential tools to characterize the variation of biodiversity. Therefore, the books and papers presented in this section provide an introductory overview of the concept of dimensionality of biodiversity, as described in Lyashevska and Farnsworth 2012 and Stevens, et al. 2013, in addition to the metrics used to calculate it. Magurran and McGill 2011 is an excellent introductory book covering the different ways to measure biological diversity as well as the properties of each of these measures. Much about how to operationalize the proof of the concept of dimensionality of biodiversity is presented in Stevens and Tello 2014, and this article demonstrates how to determine dimensionality through a set of diversity measures that make up the dimensions of biodiversity. Although empirical tests are rare, Nakamura, et al. 2018 is an excellent empirical study that evaluates the variation in the dimensionality of biodiversity in fish communities in Brazil. Stevens and Tello 2018 is another empirical assessment that analyzes the spatial variation in the dimensionality of biodiversity in New World bat communities, finding a latitudinal gradient in the dimensionality patterns of biodiversity, which tended to decrease with increasing latitude. Different contributions of species richness to explain biodiversity in space reinforce the idea that many questions about biodiversity variation remain open, as seen in Devictor, et al. 2010. Barreto, et al. 2019 is an excellent article that analyzes the relationships between different facets of diversity without using the term “dimensionality of biodiversity” (functional and taxonomic, functional and phylogenetic, or taxonomic and phylogenetic). Finally, Tucker and Cadotte 2013 describes the theoretical reasons why we can expect mismatch or congruence between the diversity metrics.

• Barreto, E., C. H. Graham, and T. F. Rangel. 2019. Environmental factors explain the spatial mismatches between species richness and phylogenetic diversity of terrestrial mammals. Global Ecology and Biogeography 28:1855–1865.

  DOI: 10.1111/geb.12999

  A global analysis in which the authors examine the spatial variation in the relationships between phylogenetic diversity and species richness, and also present the mechanisms underlying diversity patterns in different regions of the globe.

• Devictor, V., D. Mouillot, C. Meynard, F. Jiguet, W. Thuiller, and N. Mouquet. 2010. Spatial mismatch and congruence between taxonomic, phylogenetic and functional diversity: The need for integrative conservation strategies in a changing world: Spatial mismatch between diversity facets. Ecology Letters 13:130–140.

  DOI: 10.1111/j.1461-0248.2010.01493.x

  Proposes the first analytical framework to map areas of congruence and mismatch between taxonomic, functional, and phylogenetic diversity.

• Lyashevska, O., and K. D. Farnsworth. 2012. How many dimensions of biodiversity do we need? Ecological Indicators 18:485–492.

  DOI: 10.1016/j.ecolind.2011.12.016

  A crucial reference for understanding the dimensionality of biodiversity, as well as an attempt to reduce biodiversity to more important variables.

• Magurran, A. E., and B. J. McGill. 2011. Biological diversity: Frontiers in measurement and assessment. Oxford: Oxford University Press.

  Accessible and fundamental book that provides the theoretical basis for understanding the different approaches used to measure biodiversity.

• Nakamura, G., W. Vicentin, and Y. R. Suarez. 2018. Functional and phylogenetic dimensions are more important than the taxonomic dimension for capturing variation in stream fish communities. Austral Ecology 43.1: 2–12.

  DOI: 10.1111/aec.12529

  Excellent empirical assessment that demonstrates that phylogenetic and functional diversity metrics may be more important for characterizing community variation than taxonomic diversity metrics.

• Ricotta, C. 2005. Through the jungle of biological diversity. Acta Biotheoretica 53.1: 29–38.

  DOI: 10.1007/s10441-005-7001-6

  Provides an overview of biodiversity and points out the main knowledge gaps in each facet of biodiversity.

• Stevens, R. D., and J. S. Tello. 2014. On the measurement of dimensionality of biodiversity. Global Ecology and Biography 23:1115–1125.

  DOI: 10.1111/geb.12192

  Presents the methodological tools to operationalize the tests on the dimensionality of biodiversity.

• Stevens, R. D., and J. S. Tello. 2018. A latitudinal gradient in dimensionality of biodiversity. Ecography 41:2016–2026.

  DOI: 10.1111/ecog.03654

  Fundamental paper wherein the authors explicitly test the concept of dimensionality of biodiversity.

• Stevens, R. D., J. S. Tello, and M. M. Gavilanez. 2013. Stronger tests of mechanisms underlying geographic gradients of biodiversity: Insights from the dimensionality of biodiversity. PLoS ONE 8:746–853.

  DOI: 10.1371/journal.pone.0056853

  Presents for the first time the theoretical bases of the concept of dimensionality of biodiversity.

• Tucker, C. M., and M. W. Cadotte. 2013. Unifying measures of biodiversity: Understanding when richness and phylogenetic diversity should be congruent. Diversity and Distributions 19:845–854.

  DOI: 10.1111/ddi.12087

  Fundamental article for understanding the reasons why there may be a congruence and noncongruence between species richness and phylogenetic diversity.

• Whittaker, R. H. 1972. Evolution and measurement of species diversity. Taxon 21:213–251.

  DOI: 10.2307/1218190

  Discusses the ecological niche concept, the division of resources between species, and how diversity indices can help to understand the community dynamic.