Lessons from invasive species
by Shefali Mehta and Elena Tsakakis
Invasive species are a major environmental and human health threat. While they seem innocuous (e.g., who fears a plant or a domesticated cat?), they cause significant damage, especially on natural systems and species. Invasive species have led to a massive loss of global biodiversity, weakening our ecosystems and creating human health problems. We have repeatedly witnessed the adverse impacts of introduced species to new ecosystems such as early European colonialists introducing rats or goats to islands that effectively wiped out spades of native species, especially native bird populations like dodo birds. As a result of this, some island countries have incredibly staunch policies and screening for preventing new species from entering their ecosystems. Animal and Plant Health Inspection Services (APHIS), the U.S. agencies under the U.S. Department of Agriculture (USDA) tasked with managing controls, provides a spectrum of management from port inspections to monitoring human transport, like at airports to prevent travelers from tacitly bringing new species into the country on food and plants.
As a former invasive species researcher, I am particularly focused on the significant impact of climate change on invasive species and furthers the problems despite the multitude of practices put in place historically. As the attention on climate change grows, we should also address the cascade impact on existing environmental problems. Increased temperature shifts and climatic shocks exacerbate the adverse impacts of invasive species, even in areas where they were being managed effectively. This occurs due to numerous complex ecological shifts such as reducing the resilience of an ecosystem and its existing species to setting off native species on population bursts that it becomes an invasive problem entering areas where it previously could not survive or falling out of balance within the ecosystem where it evolved (e.g., the mountain pine beetle). Most, if not all, of invasive species are introduced by human activity - travel, transport, intentional release. The good news is that with this understanding of how species spread, we can reduce the damages by being mindful of what and how we are moving species.
By taking quick, intentional action, we have the power to contain the spread of invasive species and protect our existing ecosystems from dangerous outsiders. While all invasive species management starts with preventing introductions in the first place, prevention is quite costly (and somewhat impossible depending on the situation) and does not address the myriad of invasive species already present in our countries. Once a species enters and enters a new ecosystem, they can establish. Ideally, the species is detected in the new geography, allowing us to utilize the appropriate control mechanisms, if they are available. For example, emerald ash borer came through Detroit and spread has been extensive across eastern North America. The main control during the nascent stages was removal of ash trees. Now, if detected early, other mechanisms and controls exist. Once a species takes a foothold, their growth could be exponential, creating greater costs and reducing the efficacy of our control mechanisms. Dr. Robert Venette, Researcher at the U.S. Forest Service, Professor of Entomology, Director of the Minnesota Invasive Terrestrial Plants and Pests Center at the University of Minnesota, and one of my co-authors in our invasive species detection research, highlights, “There are numerous stages and mechanisms to manage invasive species. State and federal managers charged with invasive species are generally concerned about numerous species at the same time, all in a different stage of invasion with varying damages. In addition, proactive managers are increasingly concerned about species that are not in their jurisdiction yet and how to keep them out. It’s all incredibly complex.”
As a statistician, understanding spread is a fascinating problem. With invasive species, we do not have prior information on the majority of the key variables that impact decision-making, e.g., which new species will enter an ecosystem, how it will respond to a new environment, how it will interact with all the other species and the impact of human decisions around it. However, we do know that the process is not random and that with the right use of models, we can prepare and anticipate the spread of invasive species. There are three key variables that determine invasive species spread and the decision-making on the optimal time and type of management: the growth rate, the spread factor and the relative damages. Dr. Venette explains, “Invasive species pose significant challenges but they also provide numerous examples of how we can manage spread, use our resources better, collaborate across sectors, space and over time in the face of the great uncertainty that comes with invasive species.” By carefully tracking these three variables, we could mitigate some of the risk and uncertainty associated with invasive species spread, while identifying optimal management strategies and interventions when it is not possible to contain the species or prevent introductions to new ecosystems.
This holistic approach to invasive species management is relevant outside of the ecological world and perhaps most relevant today as we face the Covid-19 pandemic. Conceptually, the spread of new viruses, especially zoonotic ones like SARS-CoV-2 (COVID-19; from bats or other species), H1N1pdm09 (the 2009 swine flu pandemic; from pigs), H2N2 and H3N2 (the 1957 and 1968 avian flu pandemics; from birds), human immunodeficiency virus (HIV; from chimpanzees), etc., are the same as the underlying mechanism of invasive species - a new species (the virus) is introduced to a new ecosystem (from another species to humans) wreaking incredible havoc.
Invasive species management rests on the ability to prevent, detect and manage the species spread in various areas without suffering economic loss - much like management of the coronavirus. Humans began with the ability to control the spread of Covid-19 by quickly quarantining and preventing the spread to new populations. However, once quick and timely quarantining and prevention was missed, that control mechanism was lost, thus we are facing an even greater challenge: exponential growth, quick and far-reaching spread, and increasingly expensive solutions in the face of enormous human health costs and unknown future impacts. Similar to how climate change is presenting new opportunities for invasive species to spread, our early decisions, coupled with our incredible volume of human movement, enabled the coronavirus to move freely throughout the populations with no real solutions for control since we knew little about this virus and how to manage it within our own species.
As we reflect on the impact and spread of Covid-19 to the majority of the world’s countries, our ability to fully bring our expertise and human brainpower to the problem were inhibited by several problems, shared by invasive species management- however, in these problems lies the solution, not only to such issues as disease spread or invasive species management, but societal responses to catastrophic shocks that impact the environment and our society:
Increase upfront action and investment such as detection. We cannot manage what we do not know. For example, when managing forests, we can not know what species are there if we do not actively engage in detection activities. Similarly, with limited and generally low coronavirus testing, every known case of the virus represents a number of unknown cases that exist in the population. Low or infrequent detection has been partially addressed after 6+ months of Covid but still remains a major obstacle in most geographies. Cancer treatments effectiveness increased as our ability to detect cancer earlier improved. Detection is directly linked to effective management and reducing damages.
Ability to quickly scale sufficiently diverse data. We face not only an epidemiological problem, but a massive data problem of incomplete data, censored data, truncated data and further worsened by a lack of coherent and consistent data gathering protocols so researchers and medical staff across geographies can gather and share data to allow us to fully and quickly understand how the virus interacts with different variables such as age, diseases, different treatments, even different genetics. This is a massive data problem thus our ability to coordinate, collect and share data are critical. The lack of clear and structured rules on data gathering and sharing prevents us from meaningful progress on a global scale.
Full and complete sharing and coordination of global research. Science only works when we come together and share. Our podcast repeatedly highlights the importance of sharing knowledge globally from ice to climate to biodiversity to agriculture. Although there are political and geographic boundaries influencing our response to Covid-19, there is no value in having boundaries on research. Cross-pollination and communicating across disciplines is incredibly important. Accelerated innovation often comes on the heels of combining divergent perspectives and insights. Research works only when we share it - it gains value from its practical implications for people living outside the research world.
Much of the work that Open Rivers has focused and collaborated on has centered around issues related to optimizing investment in research and action at the right time. This includes work such as identifying and scaling diverse data that fuels models to work focused on engaging in knowledge and tech transfer across industries, sectors and geographies. Our network fuels our ability to overcome data problems, coordinate across disciplines and tackle problems beyond the traditional scope.
It was personally frustrating to watch the early and on-going political and societal responses to the coronavirus pandemic given my personal experiences with global invasive species research and work. Even during my graduate research days, I connected to and worked with researchers through the U.S., the U.K., Australia, Canada and beyond, experiencing the vast knowledge and benefits of global sharing. A network of knowledge and experts existed for these spread and management models. We have been studying them, using them and learning from them for decades. They have been applied in human health, agriculture, livestock and many more fields. It was unclear why there was limited focus on optimizing clear global data sharing and communication to effectively leverage that wealth of knowledge. However, I remain grateful for this network and community that I continue to build and work with through our on-going efforts to improve agricultural health, the environment and our communities. I hope that now, more than ever, we see the criticality of detecting and understanding an issue, collecting and sharing complete data and global, multidisciplinary scientific collaboration to meet the growing challenges facing us today.