Author: Emy Tran

A Critical Review of

Posted on by Emy Tran

Invasive Species in Penguin Worlds:

An Ethical Taxonomy of Killing for Conservation

Within this study, Van Dooren (2011) evaluates numerous different conservation strategies used on an endangered population of small penguins (Eudyptula minor) living in Sydney’s North Harbour, to explore which types of intervention, both human and non-human, are acceptable, and assess the ways in which we justify these interventions. Van Dooren (2011) explores many of the reasons that the term “invasive” has been deemed so problematic. Specifically, this article focuses on investigating much of the conservation legislation and practice within New South Wales, and the somewhat unusual methods that are employed to classify these various organisms. This article highlights the need to reconsider current invasive species management strategies, as opposed to being innately attracted to the “easiest” solution, instead prompting open and inclusive conversations about the goals, values, and priorities of all parties involved to create more multifaceted management solutions.  

Van Dooren (2011) explores various attempts to manage predation threats to an endangered population of little penguins (Eudyptula minor) living in Sydney’s North Harbour. Van Dooren (2011) begins by introducing the first threat to the small penguins, in the form of the exotic red fox (Vulpes vulpes). The solution offered for this species of concern was total eradication through baited poison traps. This practice was conducted widely, not only within the Sydney Harbour National Park, a known area of habitat for the small penguins, but also throughout many local councils as they engage in intensive red fox control. While consuming the poison does eventually result in death, it first causes the foxes to engage in ‘manic running, yelping, shrieking, and then collapse and convulsions’, all of which usually lasts several hours” (Van Dooren, 2011). This very controversial, lethal control method was allowed to continue largely as a result of the simplistic divide that exists between native and exotic species within conservation legislation in New South Wales. This mass slaughtering continued even after biologists had raised significant ecological concerns with the eradication of the foxes, as removal had been known to lead to increased mortality among some native birds and animals throughout the area. Additionally, without the foxes, rabbit populations have on occasion exploded, resulting in additional problems for valued native herbivores and plant species. 

Van Dooren (2011) goes on to discuss a considerable native threat to the little penguin population, the New Zealand fur seal (Arctocephalus forsteri). When proposing solutions for this issue, the fur seals were approached very differently than the foxes, largely in that they are presented as ‘native’ to the area, and therefore engaged in ‘natural predation’ of this colony. It is also highlighted that it is important to recognize that fur seals differ from foxes in that not every fur seal will eat the little penguin species, as a species. These seals are certainly not small penguin specialists; however, there are documented examples of New Zealand fur seal populations that relied quite significantly on them for a large part of their diet. The solution introduced to deal with this threat to the little penguin colony was essentially to ignore this issue. There was no mention of this native fur seal species in the protection and restoration plans for the small penguin population, indicating that since they are native to the ecosystem as the species of concern, there is no need to prevent their killing of the already shrinking population, an obvious double standard.

This article juggles with the problematic idea of coining the species’ “invasiveness” as it applies to the various predators of these small penguins. Van Dooren (2011) also uses these case studies to explore the influence of these rhetorical distinctions in determining species as threats, not only in the context of the continuity of this penguin colony, but also in a broader ecological sense. Additionally, Van Dooren (2011) mentions that in certain cases, native species have been referred to as “invasive pests,” largely when they induce prolonged substantial damage to other native species. Van Dooren (2011) argues that along with these “invasive” natives frequently comes a recent history of human actions altering their population or distribution, resulting in their destructive title. So we ask, in the absence of the convenient simplification of harmful being synonymous with invasive, how do we determine appropriate regulatory actions to take against these species, or if we should act at all? What kinds of interventions, either from humans or nonhumans, are warranted, and which are deemed too extreme? Van Dooren (2011) argues that by placing a binary divide between native and exotic species, experts fail to acknowledge the dynamic and ever-changing nature of the ecological systems these species exist in. These divides frequently act as a justification for which species should be protected or destroyed, as their values are intrinsically tied to the terminology

One critique that I have of this article is just how heavily it leans into critique. While Van Dooren (2011) does a great job at pointing out several of the extremely problematic aspects of designing and enacting invasive species management plans, both on an ecological and ethical level, he falls flat in describing any specific actionable solutions for these issues. Furthermore, Van Dooren (2011) creates his narrative through very rose colored glasses, leaning very heavily into the idea that killing should be a last resort. While I do not necessarily disagree with the fact that killing should be taken very seriously, and every other option should first be examined, it is willfully ignorant to state that there is never a case where it is the most practical solution. Finally, on an accessibility level, this article is written in a form that relies very heavily on jargon. This article discusses various aspects of invasive species management that must take place in highly human-dominated, urban, and suburban areas. As a result, Van Dooren (2011) has structured this article in a way that is more palatable to the general public; however, he did not translate that same consideration to the vocabulary of the article. This article could definitely be improved upon by relying less on jargon and making the language more accessible to a multitude of audiences. 

Source: 

Van Dooren, T. (2011). Invasive species in penguin worlds: An ethical taxonomy of killing for 

conservation. Conservation and Society, 9(4), 286. https://doi.org/10.4103/0972-4923.92140

A Review of Dupuis-Desormeaux et al.’s (2022) “Re-evaluating invasive species in degraded ecosystems: a case study of red-eared slider turtles as partial ecological analogs”

Posted on by Emy Tran

In this article, Dupuis-Desormeaux et al. (2022) discuss the manner in which introduced species are frequently labeled as “bad,” without first considering their potential to promote the ecological functions of degraded ecosystems. This paper is extremely significant in the world of conservation work, as it asks its audience to completely reevaluate what an invasive species means for an ecosystem, and for most conservation biologists, that would mean considering an invasive species as beneficial. The species that Dupuis-Desormeaux et al. (2022) ask their audience to reconsider is the red-eared slider (Trachemys scripta elegans), but the idea presented by this paper goes much further than just the red-eared slider. The paper suggests that under certain circumstances, some invasive species may be beneficial to an ecosystem, or at least contribute to some ecosystem function. This idea is relatively foreign to most, as we are taught on a large scale that invasive species are damaging to ecosystems. This paper introduces that invasive species may not just be bad for ecosystems, and that they could even be used methodologically to repair damaged ecosystems. 

Dupuis-Desormeaux et al. (2022) ask audiences to completely reevaluate how they view the red-eared slider, considering beyond the many threats that they pose, and instead assessing how they may perform as “contributors to ecosystem functions in degraded” habitat. Turtle species globally provide paramount ecosystem functions. This article classifies these functions into six categories: biomass contributions, energy flow and scavenging value, mineral cycling and bioaccumulation, trophic status, seed dispersal and germination enhancement, and bioturbation in soil dynamics. Like most turtle species, red-eared sliders perform all six of these ecosystem services; however, as Dupuis-Desormeaux et al. (2022) highlight, this species is deemed extremely undesirable, even in habitats where native turtles have been eradicated and are no longer able to perform such services. It is important to note that this article does not advocate for the further release of red-eared sliders into wild and natural spaces; however, it offers that in the current ecosystem of turtle populations declining precipitously as a result of increased anthropogenic pressures, especially overutilization and habitat destruction, red bearded slides, being the prolific species that it is, may be able to provide ecosystem restoration services in habitats that have become to degraded for native species to occupy. 

While reading this paper, I began to question whether red-eared sliders have been studied sufficiently to warrant their classification as an invasive species. In several sections discussing the ecological effects of red-eared sliders in non-native habitats, the author notes that many of the proposed impacts remain inconclusive due to a lack of comprehensive research. This raises an important question: what criteria must be met for a species to be officially designated as “invasive”? If, as the author hints, the red-eared slider has never been proven to have all of the suggested negative impacts on ecosystems, what is distinguishing the turtle as an invasive species rather than an introduced species? However, this species has been proven and is largely known as a prolific invasive species. Given the red-eared slider’s listing as one of the top 100 worst invasive species by the IUCN due to its significant global ecological impacts, allowing populations to remain unchecked poses a legitimate risk of rapid and uncontrolled population growth.

The author suggests that in some cases, it may be beneficial to allow red-eared sliders to remain in their non-native environments, as they may be filling vacant ecological niches. While this idea may seem reasonable in the short term, the paper also highlights that more habitats are becoming suitable for these turtles, potentially allowing their populations to expand further. If their numbers continue to increase, it is plausible that they may enter ecosystems where they could have detrimental effects. Additionally, if red-eared sliders are allowed to persist in non-native areas, there is the possibility of hybridization with native turtle species, such as the yellow-bellied slider. This poses further issues concerning the significance of said hybridization, and its potential to be used to increase genetic diversity rather than eradicate local existing species. This case is also quite interesting as although hybridization is a natural phenomenon, the global span of this species could have broader implications, contributing to the creation of several hybrid species.

Reference: Dupuis-Desormeaux, M., Lovich, J.E. & Whitfield Gibbons, J. Re-evaluating invasive species in degraded ecosystems: a case study of red-eared slider turtles as partial ecological analogs. Discov Sustain 3, 15 (2022). https://doi.org/10.1007/s43621-022-00083-w

Critical Review of Crowley et al.’s “Conflict in invasive species management”

Posted on by Emy Tran

Crowley, S. L., Hinchliffe, S., & McDonald, R. A. (2017). Conflict in invasive species management. Frontiers in Ecology and the Environment, 15(3), 133–141. https://doi.org/10.1002/fee.1471

The introduction and establishment of invasive species are leading causes in global biodiversity loss. These species not only actively outcompete native and endemic species that inhabit similar environments, but can also disrupt and alter their new habitat, completely shifting the ecological dynamics that exist within all components, both biotic and abiotic, of the system. The establishment of an invasive species can cause significant damage to the population of many native species, and can even lead to local and species extinctions.

Invasive species exist within the context of their environments. This means that just because a species may be considered invasive in one area, it is not by default deemed invasive in all locations. Additionally, not all introduced or non-native species are considered invasive. In fact, a majority of non-native and introduced species are not considered invasive to their introduced range. For an introduced species to be considered invasive, it had to produce some sort of harm, generally economically, environmentally, or to human health. This harm can be realized through a multitude of ways, including damaging agricultural fields and crops. Many invasive species have been known to negatively impact agriculture and farmland, costing both farmers and governments hundreds of millions of dollars annually. Additionally, invasive species can negatively impact human health by spreading diseases. An introduced species, acting as a vector, can spread pathogens to numerous individuals, resulting in the spread of both existing diseases and potentially new illnesses. If the introduced vector species fits the criteria of an invasive species, its ability to spread disease would be greater, resulting in an increased infection rate in the human population. This would result in significant economic damage, as governments would be required to develop treatments, medications, and vaccines, and mitigate the impacts of the invasive species. 

These species also disrupt ecological systems and cause significant environmental damage. Invasive species are often extreme generalist species, meaning that they thrive in a large variety of conditions; because of this, these species frequently outcompete native species for resources such as food, nesting locations, growing spaces, etc. Invasive species are also quite efficient at reproducing and spreading, allowing them to further establish and extend their range. These species also cause economic damage this way, as governments will frequently make efforts to combat the impacts of an invasive species once it has been established. These efforts are quite economically intensive and can cost governments millions of dollars.

This study, published by Crowley et al. in 2017, evaluated the patterns in which conflicts arise within invasive species management, as well as identifying some of the more divisive management strategies, and why some of these conflicts arise initially. Sociopolitical issues are a common ignition of conflict, as management strategies have differing impacts on different individuals, communities, and cultures. Another common cause of conflict is the typically used top-down control approach, as this method often fails to recognize the more minute details of the issue; this approach also isolates the general public from the issue, as centralized authorities are making the decisions. Once a conflict has been inflicted, Crowley et al. (2017) suggest that there are two main drivers in accelerating conflict: polarization, often driving discussions to feel black and white, and escalation, which occurs as the conflict and number of involved parties grow. Escalated conflicts are self-perpetuating and can often reach a point where “winning” becomes more prominent than the initial invasive species issue. This study suggests making shifts in our existing invasive species management practices by promoting more openness in communication, placing emphasis on the context of the ecosystem, and fostering early public involvement to generate more productive management strategies. 

Figure 1. 

This study recognises its own complexities by acknowledging that each situation is entirely unique and each of the variables within these situations is unpredictable. It, however, does not offer any solutions for how to account for this variability. Instead, it offers that individuals, when engaged in conflict, tend to behave in predictable ways, allowing researchers to identify these behaviors. One potential avenue for improvement would be to explore the correlation that exists between the number of variables involved in a situation and the unpredictability of the conflict. This would allow researchers to understand more specifically how these conflicts arise and accelerate. Furthermore, this study only briefly considers actual case studies. As a result, we can only consider invasive species management strategies and their consequential conflicts, hypothetically. Due to the constraints of this study, the authors were not able to observe these species and these practices in the field. A future study may benefit by assessing these conflicts and behavior patterns firsthand, with an actively invasive population currently undergoing management practices. Overall conclusions of the study suggest that wildlife managers and officials should put more energy into proactive and anticipatory invasive species management approaches, such as monitoring programs and preventive outreach initiatives. While this would be ideal when it comes to avoiding conflict within invasive species management, as you would have to interact with fewer stakeholders, it does not account for situations in which the invasive species are already established in a new habitat. The article goes on to explain the steps that Crowley et al. (2017) identified one should take in order to minimize the risk of conflict when planning and applying invasive species management strategies; however, I propose a further study that focuses only on established invasive species populations within a given area that are managed in different ways. This study would assess how conflict arises in similar settings, and would offer a more controlled version of the study, allowing us to identify ways to minimize conflict when managing already established invasive species.