Old and new challenges in using species diversity for assessing biodiversity

Abstract

Although the maintenance of diversity of living systems is critical for ecosystem functioning, the accelerating pace of global change is threatening its preservation. Standardized methods for biodiversity assessment and monitoring are needed. Species diversity is one of the most widely adopted metrics for assessing patterns and processes of biodiversity, at both ecological and biogeographic scales. However, those perspectives differ because of the types of data that can be feasibly collected, resulting in differences in the questions that can be addressed. Despite a theoretical consensus on diversity metrics, standardized methods for its measurement are lacking, especially at the scales needed to monitor biodiversity for conservation and management purposes. We review the conceptual framework for species diversity, examine common metrics, and explore their use for biodiversity conservation and management. Key differences in diversity measures at ecological and biogeographic scales are the completeness of species lists and the ability to include information on species abundances. We analyse the major pitfalls and problems with quantitative measurement of species diversity, look at the use of weighting measures by phylogenetic distance, discuss potential solutions and propose a research agenda to solve the major existing problems.

Phylogenetic diversity as a window into the evolutionary and biogeographic histories of present-day richness gradients for mammals

“…At local scales, patterns of phylogenetic over-and under-dispersion are frequently used to infer ecological processes structuring community composition; for example, competition or environmental filtering [108]. Recent efforts have moved towards incorporating evolutionary history within diversity metrics relevant at ecological scales [21,109,110]. While PD is complementary to other species' diversity metrics [21], applying PD to inform local conservation strategies can be problematic.…”

“…While many challenges remain in accurately characterizing species diversity [21], the inclusion of phylogenetic information is providing additional insight into diversity gradients. Here, we demonstrate how phylogenetic information can be applied to infer the dynamics of diversity gradients through time.…”

“…Palmer [61] recognizes over 120). Explanations can be variously categorized, with ecological explanations linked to species coexistence and assembly rules, the focus at finer spatial scales, and biogeographic processes, including species-area relationships and environmentrichness gradients, the focus at larger regional scales [21]. Here, we consider evolutionary explanations, which fall into two broad classes, (i) a longer time for speciation [62][63][64], and (ii) faster net diversification (speciation-extinction) [65,66].…”

“…water purification, erosion control or crop pollination). Because it is difficult to partition contribution to ecosystem services across multiple habitats and biomes, at larger spatial scales, counting species remains the most common approach to quantifying diversity, and even then there remain many challenges (see [21]). However, if we assume that more closely related species are also more functionally similar, phylogenetic metrics can allow us to consider both richness and function simultaneously [22][23][24][25].…”

Plant biodiversity of beech forests in central-northern Italy: a methodological approach for conservation purposes

“…Quando q=0, allora D=S, quindi D sarà uguale al numero di specie, quando q=1 allora D assumerà il valore dell'esponenziale dell'indice di Shannon-Weiner, e quando q=2 allora D sarà uguale all'inverso dell'indice di Simpson (Chiarucci et al 2011).…”