Assessing the utility of conserving evolutionary history

Abstract

It is often claimed that conserving evolutionary history is more efficient than species‐based approaches for capturing the attributes of biodiversity that benefit people. This claim underpins academic analyses and recommendations about the distribution and prioritization of species and areas for conservation, but evolutionary history is rarely considered in practical conservation activities. One impediment to implementation is that arguments related to the human‐centric benefits of evolutionary history are often vague and the underlying mechanisms poorly explored. Herein we identify the arguments linking the prioritization of evolutionary history with benefits to people, and for each we explicate the purported mechanism, and evaluate its theoretical and empirical support. We find that, even after 25 years of academic research, the strength of evidence linking evolutionary history to human benefits is still fragile. Most – but not all – arguments rely on the assumption that evolutionary history is a useful surrogate for phenotypic diversity. This surrogacy relationship in turn underlies additional arguments, particularly that, by capturing more phenotypic diversity, evolutionary history will preserve greater ecosystem functioning, capture more of the natural variety that humans prefer, and allow the maintenance of future benefits to humans. A surrogate relationship between evolutionary history and phenotypic diversity appears reasonable given theoretical and empirical results, but the strength of this relationship varies greatly. To the extent that evolutionary history captures unmeasured phenotypic diversity, maximizing the representation of evolutionary history should capture variation in species characteristics that are otherwise unknown, supporting some of the existing arguments. However, there is great variation in the strength and availability of evidence for benefits associated with protecting phenotypic diversity. There are many studies finding positive biodiversity–ecosystem functioning relationships, but little work exists on the maintenance of future benefits or the degree to which humans prefer sets of species with high phenotypic diversity or evolutionary history. Although several arguments link the protection of evolutionary history directly with the reduction of extinction rates, and with the production of relatively greater future biodiversity via increased adaptation or diversification, there are few direct tests. Several of these putative benefits have mismatches between the relevant spatial scales for conservation actions and the spatial scales at which benefits to humans are realized. It will be important for future work to fill in some of these gaps through direct tests of the arguments we define here.

Formal Links between Feature Diversity and Phylogenetic Diversity

“…Efficient algorithms for finding maximum PD sets are available (Bordewich et al (2008)), the metric has been extended to networks (Minh et al (2009)), and there are countless case studies that both measure and optimize PD for conservation (see, e.g., Pollock et al (2017)); Faith’s original paper has been cited in excess of 2000 times. A recent review (Tucker et al, 2019) considered the literature concerning both the empirical correlations between PD and feature diversity, and the expected relationship between PD and various conservation values.…”

Nitrogen alters effects of disturbance on annual grassland community diversity: Implications for restoration

“…Understanding the consequences of disturbance and changing resource supply for community phylogenetic diversity can also support managers conducting ecosystem restoration (Barak et al, ; Hipp et al, ). Conserving evolutionary information is an important aspect of biodiversity conservation (Faith, ; ) and phylogenetic diversity of plant communities can identify mechanisms linking diversity with ecosystem function (Cadotte, Cardinale, & Oakley, ; Cadotte et al, ), ecosystem stability (Cadotte, Dinnage, & Tilman, ) and diversity of other trophic levels (Cadotte et al, ; Dinnage, Cadotte, Haddad, Crutsinger, & Tilman, ). Phylogenetic diversity can thus be an important metric in addition to taxonomic diversity for quantifying restoration outcomes and meeting the key goal of functioning and resilient ecosystems (Barak et al, ; Hipp et al, ; Thorpe & Stanley, ).…”

Global priorities for conservation of reptilian phylogenetic diversity in the face of human impacts

“…Prioritising species which represent large amounts of unique PD can potentially conserve more phylogenetic and trait diversity than phylogenetically uninformed prioritisations 19,20 , though the relationship between PD and trait diversity is complex and variable 20 . Phylogenetically informed prioritisations are used to direct conservation efforts on the ground, the most notable example of which is the Zoological Society of London's EDGE of Existence programme.…”