Christopher Lean

The introduction of new genetic material into wild populations, using novel biotechnology, has the potential to fortify populations against existential threats, and, controversially, create wild genetically modified populations. The introduction of new genetic variation into populations, which will have an ongoing future in areas of conservation interest, complicates long-held values in conservation science and park management. I discuss and problematize, in light of genetic intervention, what I consider the three core goals of conservation science: biodiversity, ecosystem services, and wilderness. This uneasy relationship, however, does not forgo the use of such interventions. I argue there is a case for the application of this technology within some interpretations of the moral frameworks of wilderness and biodiversity, despite apparent conflict between these values and the technology, and the possibility that this technology's use displays some limitations of the ecosystem services framework. Ultimately, the advent of biotechnology assisted restoration highlights the need for us to reevaluate our ethical concepts of conservation at times of global environmental and technological change.

Two or more independent species lineages can fuse through an evolutionary transition to form a single lineage, such as in the case of eukaryotic cells, lichens, and coral. The fusion of two or more independent lineages requires intermediary steps of increasing selective interdependence between these lineages. We argue a precursory selective regime of such a transition can be Multilevel Selection 1 (MLS1). We propose that intraspecies MLS1 can be extended to ecological multispecies arrangements. We develop a trait group selection (MLS1) model applicable to multispecies mutualistic interactions. We then explore conditions under which such a model could apply to mutualistic relationships between pollinators and plants. We propose that MLS1 could drive transitions towards higher interdependency between mutualists and stabilise obligate mutualisms in the face of invasion by cheater variants. This represents a radical extension of multilevel selection theory, applying it to the evolution of multispecies populations, and indicating new avenues for researching ecological community evolution.

Understanding community-level selection using Lewontin’s criteria requires both community-level inheritance and community-level heritability, and in the discipline of community and ecosystem genetics, these are often conflated. While there are existing studies that show the possibility of both, these studies impose community-level inheritance as a product of the experimental design. For this reason, these experiments provide only weak support for the existence of community-level selection in nature. By contrast, treating communities as interactors (in line with Hull’s replicator-interactor framework or Dawkins’s idea of the “extended phenotype”) provides a more plausible and empirically supportable model for the role of ecological communities in the evolutionary process.

Eric Katz in Zombie Arguments defends the thesis authenticity is indispensable to conservation. I agree. However, I argue authenticity appears in degrees and can be reclaimed by populations through their continuing evolutionary responses to the world. This means that interventions that diminish the value of a population through reducing their authenticity can be permitted in limited cases. When our actions retain the remaining authentic features in a threatened population we should allow such a diminishment as authenticity can be reclaimed in time.

Some critics of invasion biology have argued the invasion of ecosystems by nonindigenous species can create more valuable ecosystems. They consider invaded communities as more valuable because they potentially produce more ecosystem services. To establish that the introduction of nonindigenous species creates more valuable ecosystems, they defend that value is provisioned by ecosystem services. These services are derived from ecosystem productivity, the production and cycling of resources. Ecosystem productivity is a result of biodiversity, which is understood as local species richness. Invasive species increase local species richness and, therefore, increase the conservation value of local ecosystems. These views are disseminating to the public via a series of popular science books. Conservationists must respond to these views, and I outline a method of rejecting such arguments against controlling invasive species. Ecological systems are valuable for more than local productivity and biodiversity is not accurately described by a local species count.

If ecological systems are functionally organised, they can possess functions or malfunctions. Natural function would provide justification for conservationists to act for the protection of current ecological arrangements and control the presence of populations that create ecosystem malfunctions. Invasive species are often thought to be malfunctional for ecosystems, so functional arrangement would provide an objective reason for their control. Unfortunately for this prospect, I argue no theory of function, which can support such normative conclusions, can be applied to large scale ecosystems. Instead ecological systems have causal structure, with small clusters of populations achieving functional arrangement. This, however, does not leave us without reason to control invasive species. We can look at the causal arrangement of ecological systems for populations that support ecological features that we should preserve. Populations that play a causal role in reducing biodiversity should be controlled, because biodiversity is a good all prudent agents should want to preserve.

If ecological systems are functionally organised, they can possess functions or malfunctions. Natural function would provide justification for conservationists to act for the protection of current ecological arrangements and control the presence of populations that create ecosystem malfunctions. Invasive species are often thought to be malfunctional for ecosystems, so functional arrangement would provide an objective reason for their control. Unfortunately for this prospect, I argue no theory of function, which can support such normative conclusions, can be applied to large scale ecosystems. Instead ecological systems have causal structure, with small clusters of populations achieving functional arrangement. This, however, does not leave us without reason to control invasive species. We can look at the causal arrangement of ecological systems for populations that support ecological features that we should preserve. Populations that play a causal role in reducing biodiversity should be controlled, because biodiversity is a good all prudent agents should want to preserve.

I will entertain and reject three arguments which putatively establish that the individuals produced through de-extinction ought to be the same species as the extinct population. Forms of these arguments have appeared previously in restoration ecology. The first is the weakest, the conceptual argument, that de-extinction will not be de-extinction if it does not re-create an extinct species. This is misguided as de-extinction technology is not unified by its aim to re-create extinct species but in its use of the remnants of extinct populations as a resource. The second is the argument from authenticity; the populations produced by de-extinction technologies will be inauthentic if they are not of the extinct species and, therefore, will not be valuable. I argue authenticity is not required in conservation as the value of authenticity varies between people and cultures, and the novelty of de-extinct species will be equally desirable in many cases. The third argument is from retributive justice; we need the de-extinct population to have the same species identity as we owe a moral debt to the extinct population. I find the case for retributive justice unconvincing and argue that acting as if we have a duty to resurrect extinct species will result in a world with less species. Ultimately all the arguments that connect de-extinction technology to species identity fail, leaving us to consider a more complex calculus for the justification of de-extinction in conservation.

The question of whether there are laws of nature in ecology has developed substantially in the last 20 years. Many have attempted to rehabilitate ecology’s lawlike status through establishing that ecology possesses laws that robustly appear across many different ecological systems. I argue that there is still something missing, which explains why so many have been skeptical of ecology’s lawlike status. Community ecology has struggled to establish what I call a General Unificatory Theory. The lack of a GUT causes problems for explanation as there are no guidelines for how to integrate the lower-level mathematical and causal models into a larger theory of how ecological assemblages are formed. I turn to a promising modern attempt to provide a unified higher-level explanation in ecology, presented by ecologist Mark Vellend, and advocate for philosophical engagement with its prospects for aiding ecological explanation.

Lynch et al. propose an extremely useful framework to assess microbiome research. By utilising advances in the causation literature, they argue that many of the claims in microbiome research are ‘weak or misleading’ as these claims lack stability, specificity, or proportionality. In the final paragraph before the conclusion they entertain and rapidly dismiss the ‘ecological version’ of microbiomes, in which microbiome properties are emergent from their constituent populations and can fulfil Koch’s postulates. I assess the possibility of microbiomes having emergent causal efficacy on host health and suggest they can.

Conservation has often been conducted with the implicit internalization of Aldo Leopold’s claim: “A thing is right when it tends to preserve the integrity, stability and beauty of the biotic community.” This position has been found to be problematic as ecological science has not vindicated the ecological community as an entity which can be stable or coherent. Ecological communities do not form natural kinds, and this has forced ecological scientists to explain ecology in a different manner. Individualist approaches to ecological systems have gained prominence. Individualists claim that ecological systems are better explained at the population level rather than as whole communities. My thesis looks at the implications of the current state of ecological science on conservation biology and emphasizes the importance of biodiversity as assessed at the population level. I defend the position that biodiversity should represent taxonomy and be quantified in reference to phylogenetic structure. This is a defence of biodiversity realism, which conceives of biodiversity as a natural quantity in the world which is measurable, valuable to prudent agents, and causally salient to ecological systems. To address how biodiversity at the population level relates to larger ecological systems I create a methodology designed to identify the relevant ecological system which biodiversity maintains and is maintained by biodiversity. This is done through the context dependent modelling of causal networks indexed to populations. My causal modelling methodology is then utilized to explicate ecological functions. These chapters together provide a framework for conservation science, which can then be applied to novel problems. The final section of the thesis utilises this framework to address whether de-extinction is a worthwhile conservation technique.

Ecological communities are seldom, if ever, biological individuals. They lack causal boundaries as the populations that constitute communities are not congruent and rarely have persistent functional roles regulating the communities’ higher-level properties. Instead we should represent ecological communities indexically, by identifying ecological communities via the network of weak causal interactions between populations that unfurl from a starting set of populations. This precisification of ecological communities helps identify how community properties remain invariant, and why they have robust characteristics. This respects the diversity and aggregational nature of these complex systems while still vindicating them as units worthy of investigation.

Biodiversity is a key concept in the biological sciences. While it has its origin in conservation biology, it has become useful across multiple biological disciplines as a means to describe biological variation. It remains, however, unclear what particular biological units the concept refers to. There are currently multiple accounts of which biological features constitute biodiversity and how these are to be measured. In this paper, I draw from the species concept debate to argue for a set of desiderata for the concept of “biodiversity” that is both principled and coheres with the concept’s use. Given these desiderata, this concept should be understood as referring to difference quantified in terms of the phylogenetic structure of lineages, also known as the ‘tree of life’.

This chapter explores the idea that phylogenetic diversity plays a unique role in underpinning conservation endeavour. The conservation of biodiversity is suffering from a rapid, unguided proliferation of metrics. Confusion is caused by the wide variety of contexts in which we make use of the idea of biodiversity. Characterisations of biodiversity range from all-variety-at-all-levels down to variety with respect to single variables relevant to very specific conservation contexts. Accepting biodiversity as the sum of a large number of individual measures results in an empirically intractable framework. However, large-scale decisions cannot be based on biodiversity variables inferred from local conservation imperatives because the variables relevant to the many systems being compared would be incommensurate with one another. We therefore need some general conception of biodiversity that would make tractable such large-scale environmental decision-marking. We categorise the large array of strategies for the measurement of biodiversity into four broad groups for consideration as general measures of biodiversity. We compare common moral justifications for the conservation of biodiversity and conclude that some form of instrumental value is the most plausible justification for biodiversity conservation. Although this is often interpreted as a reliance on option value, we opt for a broadly consequentialist characterisation of biodiversity conservation. We conclude that the best justified general measure of biodiversity will be some form of phylogenetic diversity.

One of the major developments in cancer research in recent years has been the construction of models that treat cancer as a cellular population subject to natural selection. We expand on this idea, drawing upon multilevel selection theory. Cancer is best understood in our view from a multilevel perspective, as both a by-product of selection at other levels of organization, and as subject to selection at several levels of organization. Cancer is a by-product in two senses. First, cancer cells co-opt signaling pathways that are otherwise adaptive at the organismic level. Second, cancer is also a by-product of features distinctive to the metazoan lineage: cellular plasticity and modularity. Applying the multilevel perspective in this way permits one to explain transitions in complexity and individuality in cancer progression. Our argument is a reply to Germain’s scepticism towards the explanatory relevance of natural selection for cancer. The extent to which cancer fulfills the conditions for being a paradigmatic Darwinian population depends on the scale of analysis, and the details of the purported selective scenario. Taking a multilevel perspective clarifies some of the complexities surrounding how to best understand the relevance of evolutionary thinking in cancer progression