| Literature DB >> 30151046 |
Abstract
Despite wide acceptance that conservation could benefit from greater attention to principles and processes from evolutionary biology, little attention has been given to quantifying the degree to which relevant evolutionary concepts are being integrated into management practices. There has also been increasing discussion of the potential reasons for a lack of evolutionarily enlightened management, but no attempts to understand the challenges from the perspective of those making management decisions. In this study, we asked conservation managers and scientists for their views on the importance of a range of key evolutionary concepts, the degree to which these concepts are being integrated into management, and what would need to change to support better integration into management practices. We found that while managers recognize the importance of a wide range of evolutionary concepts for conservation outcomes, they acknowledge these concepts are rarely incorporated into management. Managers and scientists were in strong agreement about the range of barriers that need to be overcome, with a lack of knowledge reported as the most important barrier to better integration of evolutionary biology into conservation decision-making. Although managers tended to be more focused on the need for more training in evolutionary biology, scientists reported greater engagement between managers and evolutionary biologists as most important to achieve the necessary change. Nevertheless, the challenges appear to be multifaceted, and several are outside the control of managers, suggesting solutions will need to be multidimensional.Entities:
Keywords: adaptation; conservation management; gene flow; genetic diversity; inbreeding depression; outbreeding depression
Year: 2018 PMID: 30151046 PMCID: PMC6099810 DOI: 10.1111/eva.12631
Source DB: PubMed Journal: Evol Appl ISSN: 1752-4571 Impact factor: 5.183
Areas of environmental management in which evolutionary principles and processes could be used to inform management actions
| Evolutionary principle or process | Threatened species management | Restoration and revegetation | Invasive species management | Protected area design | Wildlife disease management |
|---|---|---|---|---|---|
| Genetic diversity | |||||
| Genetic diversity provides the variation through which adaptation and evolution can occur. Genetic diversity increases effective population size, which is critical to the viability of populations. Small, fragmented populations are more vulnerable to the loss of genetic diversity |
Threatened species tend to have small, fragmented populations, with low effective population sizes and vulnerability to loss of genetic diversity through genetic drift and inbreeding depression (Ellstrand & Elam, | To ensure the long‐term viability of restoration efforts, seed should be sourced from multiple populations (Broadhurst et al., |
When managing invasive species, the goal is to minimize genetic diversity. Biosecurity measures can be used to avoid multiple introductions that increase the genetic diversity of invasive populations (Simberloff, |
Ensure protected areas can support sufficiently large populations to maintain genetic diversity (Mace & Purvis, |
Disease can reduce the size of affected populations, which will reduce genetic diversity. |
| Adaptation | |||||
| Adaptation is the process by which selection acts on standing genetic diversity to enable species to respond to environmental change |
Threats that drive species to become threatened are acting as selection pressures that can lead to changes, some of which may be maladaptive, for example, changes in flowering time in response to warming climates that disrupt mutualisms with pollinators (Merila & Hendry, | Current conditions may not represent future conditions, so ensuring revegetated areas have a mixture of locally adapted seed, and seed from populations adapted to conditions similar to those expected to arise under climate change scenarios could improve the adaptive potential and therefore resilience of revegetated areas (Sgrò et al., |
Management activities function as a selection pressure on invasive populations, which could lead to adaptations that reduce management effectiveness (Neve et al., | The same considerations as for genetic diversity |
Ensure treatment of pathogens is performed in a way to reduce adaptations that reduce the effectiveness of control measures (Smith et al., |
| Evolution | |||||
|
Evolution is the result of changes in allele frequency within a population over generations. It is important to understand which populations will be able to adapt and which risk extinction. | Maintaining or increasing genetic diversity, and therefore adaptive potential, is critical to rapid or contemporary evolution, which can enable species to respond to rapidly changing conditions under a range of anthropogenic pressures (Hendry, Farrugia, & Kinnison, | The same consideration as for adaptation |
Management actions should consider how to limit the adaptive capacity of invasive populations and to reduce directional selection that leads to adaptations that resist control efforts (Hendry et al., | The same consideration as for genetic diversity | Pathogens can evolve resistance to treatments. Costs of adaptation can be used to manipulate evolutionary trajectories through the design of treatments that slow the evolution of resistance (Levin, Perrot, & Walker, |
| Gene flow | |||||
| Gene flow through the movement of individuals between populations can introduce new alleles that increase the genetic diversity of populations. Gene flow can benefit populations by increasing effective population size, counteracting genetic drift, reducing inbreeding depression and introducing favourable alleles. Gene flow can also be negative if it works to disrupt local adaptation or facilitates adaptation of pest species |
The small, often fragmented nature of threatened populations means that gene flow is important to maintain or restore genetic diversity (Weeks et al., |
Sourcing seed from populations that occur along an environmental gradient can maximize the adaptive capacity and resilience of restoration effects (Prober et al., |
Restrict gene flow between populations to limit genetic diversity and adaptive potential (Hendry et al., |
Ensure protected areas are well connected to facilitate gene flow among populations (Ridley & Alexander, | Gene flow can serve to increase the adaptive capacity of pathogens, but can also be used to disrupt the evolution of resistance by increasing gene flow from susceptible populations (Alphey, Coleman, Donnelly, & Alphey, |
| Inbreeding depression | |||||
| Inbreeding depression, the decreased fitness of offspring due to increased levels of homozygosity leading to the expression of deleterious recessive alleles, leads to loss of genetic diversity and demographic suppression |
Small, isolated populations are prone to inbreeding depression, which can increase extinction risk (Hedrick & Kalinowski, | Where local populations are small and fragmented, sourcing seed locally can lead to low levels of genetic diversity, and therefore a higher risk of inbreeding depression (Prober et al., | Keeping populations small and isolated will increase the chance of inbreeding depression. This can be achieved through population reduction, limiting gene flow and prioritizing management early in the invasion process before species become widespread (Simberloff, | Protected areas should be large enough and/or sufficiently connected to avoid the risk of inbreeding depression associated with small, fragmented populations | Impact of novel diseases can reduce wildlife populations to the point they are vulnerable to inbreeding depression |
| Outbreeding depression | |||||
| Outbreeding between individuals from genetically distinct populations can lead to reduced fitness through genetic incompatibility and/or maladaptation | The risk of outbreeding depression should be considered when planning translocations, using available risk assessment frameworks (Frankham et al., | The risk of outbreeding depression should be considered when selecting seed for restoration efforts, using available risk assessment frameworks (Frankham et al., | Not currently being discussed in the literature | Not currently being discussed in the literature | Not currently being discussed in the literature |
| Mating system | |||||
| Different mating systems are associated with different levels of genetic diversity and impact the relationship between census and effective population size |
Different mating systems are associated with different levels of risk of inbreeding and outbreeding depression (Weeks et al., |
Mating systems should be considered when selecting how many populations to source seed from (e.g., genetic diversity is lower in populations of selfing or asexual reproducers; Frankham, | Mating systems influence genetic diversity (e.g., lowest in asexual reproducing species) and therefore the adaptive capacity of invasive species (Frankham, | Not currently being discussed in the literature | Not currently being discussed in the literature |
| Life history strategy | |||||
| Life history traits, such as generation time, play a critical role in how quickly species can adapt to environmental change. Life history strategy also impacts the relationship between census and effective population size (e.g., when individuals reach sexual maturity) |
Life history traits influence the ability of species to adapt to changing environmental conditions (Hendry et al., | It can take a long time to realize the impact of low genetic diversity in revegetation efforts for species with long generation times (e.g., tree species; Prober et al., | Biosecurity measures should target species that can produce large numbers of propagules because they are most likely to become invasive (Simberloff, | Protected areas can be used as refuges for exploited species to reduce the impacts of life history evolution driven by selective harvesting (Baskett, Levin, Gaines, & Dushoff, | Understanding life history strategy can inform the timing of treatments because those that act after first reproduction will slow the evolution of resistance in pathogens (Hendry et al., |
Key concepts relevant to integrating evolutionary theory into conservation practice
| Concept | Definition |
|---|---|
| General concepts | |
| Genetic diversity | Genetic differences between individuals of the same species |
| Adaptation | The condition where the phenotype of individuals is well suited to the environmental conditions, such that the individuals have higher reproductive fitness. |
| Evolution | The process by which populations or species change over successive generations. |
| Specific concepts | |
| Gene flow | Movement of alleles between populations through mating between individuals from different populations |
| Inbreeding depression | Mating between closely related individuals that leads to a loss of genetic diversity and corresponding reduction in reproductive fitness |
| Outbreeding depression | Mating between genetically distinct individuals that introduces new alleles that disrupt local adaptation and lead to reduced reproductive fitness |
| Mating system | The way in which a population is structured in relation to sexual behaviour |
| Life history strategy | The way in which individuals invest in growth, reproduction and survivorship |
The 5‐point Likert scale used by respondents to score their responses to the questionnaire
| Importance | Integration | Coding |
|---|---|---|
| Not at all important | Never | 1 |
| Somewhat important | Rarely | 2 |
| Neither important nor unimportant | Sometimes | 3 |
| Important | Often | 4 |
| Very important | All the time | 5 |
| Unsure | Unsure | Missing value |
Figure 1The mean (±) importance score for different evolutionary concepts as reported by managers (black circles) and scientists (grey circles). Asterisk indicates significant difference between groups
Figure 2The mean (±) importance score for each of the evolutionary concepts based on (a) the level of education of respondents (black circles = certificate/diploma; grey circles = bachelor; open black circles = postgraduate) and (b) the level of exposure to evolutionary biology during their training (black circles = evolution and genetics; grey circles = evolution only; open black circles = genetics only; open grey circles = none)
Figure 3The mean (±) integration score for each of the evolutionary concepts as reported by (a) managers (black circles) and scientists (grey circles), and (b) the level of exposure to evolutionary biology during their training (black circles = evolution and genetics; grey circles = evolution only; open black circles = genetics only; open grey circles = none)
Figure 4The (a) barriers to and (b) opportunities for greater integration of evolutionary theory into conservation management as reported by scientists (black bars) and managers (grey bars)
Description of the barrier to better integration of evolutionary theory reported by managers and scientists
| Category Code | Description |
|---|---|
| Barriers to better integration | |
| Lack of education | A lack of training and basic understanding of the relevant concepts, their importance and/or how they should be applied to management |
| Conservation not prioritized | A lack of support for conservation from governments and the broader community, and a shift in emphasis to towards visitor management rather than conservation management |
| Lack of resources | Declines in the resources for conservation management mean funds are inadequate for on‐ground management. There are competing priorities for resources, and funding is uncertain and short‐term. Too few managers. |
| Lack of communication with scientists | A lack of engagement by scientists means there is poor translation of primary research into management programmes |
| Short‐term not long‐term | The focus of management is on dealing with immediate problems, not long‐term outcomes. There is poor understanding of how concepts can be applied to short management time frames. Evolution and management occur over different time horizons. |
| Benefit not demonstrated | There is little evidence for the application of relevant concepts to conservation management. There are no case studies that show chances are beneficial. |
| Research and monitoring | Not enough research or funding for necessary research. Research is generally academic and not focused on conservation management. Unclear what to monitor. |
| Legislation, policy and guidelines | Legislation is interpreted too narrowly and provides impediments (e.g., managing across borders) to including evolutionary processes. There is no mandate within policy to change management practices. Managers do not know how to integrate these ideas into their practices. |
| Other | Conflict between evolutionary theory and religious beliefs. Need to engage other landholders and managers for integrated management. |
| Mismatch in spatial scale | Management occurs at small scales (e.g., small, isolated areas), but evolutionary process often need to be managed at a landscape scale. |
| None | There is currently nothing preventing greater integration. |
| Concept | Not at all important | Somewhat unimportant | Neither important nor unimportant | Somewhat important | Very important | Unsure |
|---|---|---|---|---|---|---|
| Evolution | ||||||
| Adaptation | ||||||
| Genetic diversity | ||||||
| Inbreeding depression | ||||||
| Gene flow | ||||||
| Outbreeding depression | ||||||
| Mating system | ||||||
| Life history |
| Concept | Never | Rarely | Sometimes | Most of the time | Always | Unsure |
|---|---|---|---|---|---|---|
| Evolution | ||||||
| Adaptation | ||||||
| Genetic diversity | ||||||
| Inbreeding depression | ||||||
| Gene flow | ||||||
| Outbreeding depression | ||||||
| Mating system | ||||||
| Life history |