Photo: Salt cedar & giant cane, along Rio Grande, Chihuahuan Desert, Big Bend National Park. © 2017 Delena Norris-Tull
Rehabilitation of rangelands: Working with novel ecosystems
Summaries of the research and commentary by Dr. Delena Norris-Tull, Professor Emerita of Science Education, University of Montana Western,
September 2020.
In rangelands and public lands, some researchers have advocated for recognizing that eradication of invasive species may not be a feasible goal, in restoration or reclamation plans. And that we must consider how to live with a certain level of invasive species, within an ecosystem. What factors leads to this recommendation?
DiTomaso, et al., 2017, describe the detrimental effects invasive plants have had in rangeland and natural ecosystems. Invasive plants “can reduce biological diversity, threaten rare and endangered species, reduce wildlife habitat and forage, alter fire frequency, increase erosion, and deplete soil moisture and nutrient levels.” They point out that “invasive plants have been estimated to decrease range productivity by 23-75%..., native plant diversity by 44%, and abundance of animal species by 18%.” In the U.S., “it is estimated that there are over 3000 non-native plant species that have become naturalized and are able to maintain self-sustaining populations within rangelands… However, only 37-60 non-native species are considered of major [detrimental] economic and ecological importance.”
But DiTomaso, et al., 2017, also have found that “in many situations invasive plants provide benefits to the ecosystem.” They propose that, “Such changes [caused by invasive plants] can result in novel ecosystems where the focus of restoration efforts has shifted from preserving the historic species assemblages to conserving and maintaining a resilient, functional system that provides diverse ecosystem service, while supporting many human livelihoods.”
DiTomaso, et al., 2017, point out that “there are trade-offs between positive and negative impacts of invasive plants. This is most apparent in highly altered and degraded landscapes where abiotic conditions [may be] so degraded that native species are unable to naturally recover… even when mediated by restoration efforts.” In those conditions, it may be impossible to restore the ecosystem to an historic ecosystem, assuming that we know what that ecosystem looked like. In those circumstances, invasive plants “may provide a number of beneficial services, including [reducing] soil erosion, regulation of pests and disturbance regimes, purification of air and water, increasing habitat for pollinators and other species, providing nurse sites for native plant establishment, and facilitating phytoremediation…. [Additional services include] livestock or wildlife forage, wildlife habitat,… and medicinal or ornamental value.” Some invasive plant species also help improve soil nutrients.
DiTomaso, et al., 2017, propose that restoration managers “consider other tools, such as state-and-transition models and adaptive management, which provide holistic and flexible approaches for controlling invasive plants, favor more desirable plant species, and lead to ecosystem resilience.” They state that “restoration programs should focus on managing for future change that emphasizes ecosystem function, goods, and services…, maintaining genetic and species diversity, and encouraging biogeochemical processes that favor desirable species… Restoration options that remove the requirement of attaining a historic ecosystem may reduce both the effort and costs, yet may still achieve a desired outcome.”
DiTomaso, et al., 2017, go on to point out that “invasive plant management has often focused on the control of a single species without regard for the unintended consequences of the control method” and without regard for the impact of the control method on the rest of the ecosystem. It is important to examine three primary factors that enable invasive success: “prevailing environmental conditions, traits of the resident species, and traits of the invading species.”
DiTomaso, et al., 2017, suggest that rehabilitating degraded lands may be more beneficial and economically feasible than either restoration (which attempts to restore the ecosystem to some presumed historic condition) or reclamation (which often results in a “monoculture of a highly productive species”). Restoration focuses on increasing biodiversity while reclamation focuses on increased production. DiTomaso, et al., 2017, advocate for attempting the delicate balance between increased biodiversity and increased production.
DiTomaso, et al., 2017, propose that, when dealing with novel ecosystems, rehabilitation, restoration, or reclamation plans be based on intervention ecology, reducing the negative impacts of invasive species through the systematic use of multiple, combined tactics, which may include:
Indigenous ways of knowing
In her book Braiding Sweetgrass, Dr. Robin Wall Kimmerer, a plant ecologist and a tribal member of the Citizen Potawatomi Nation, provides a glimpse of indigenous ways of knowing about nature and about ecological restoration.
In the chapter, “The Sacred and the Superfund,” Dr. Kimmerer describes the destruction of the land surrounding, and the waters within Onondaga Lake, next to Syracuse, New York. For over 100 years, tons of industrial wastes, sewage, and other sources of runoff, poured into the lake. And she describes the gradual regeneration of the lake, by plants, the waters, and the earth.
“But how can we submit to despair while the land is saying ‘Help’? Restoration is a powerful antidote to despair. Restoration offers concrete means by which humans can once again enter into positive, creative relationship with the more-than-human world, meeting responsibilities that are simultaneously material and spiritual. It's not enough to grieve. It's not enough to just stop doing bad things” (Kimmerer, 2013, p. 328).
“How we approach restoration of land depends, of course, on what we believe that ‘land’ means. If land is just real estate, then restoration looks very different than if land is the source of a subsistence economy and a spiritual home. Restoring land for production of natural resources is not the same as renewal of land as cultural identity. We have to think about what land means” (Kimmerer, 2013, p. 328).
“Restoration is imperative for healing the earth, but reciprocity is imperative for long-lasting, successful restoration. Like other mindful practices, ecological restoration can be viewed as an act of reciprocity in which humans exercise their caregiving responsibility for the ecosystems that sustain them. We restore the land, and the land restores us. As writer Freeman House cautions, ‘We will continue to need the insights and methodologies of science, but if we allow the practice of restoration to become the exclusive domain of science, we will have lost its greatest promise, which is nothing less than a redefinition of human culture’” (Kimmerer, 2013, p. 336).
“A 1994 statement from the Indigenous Environmental Network put it best: ‘Western science and technology, while appropriate to the present scale of degradation, is a limited conceptual and methodological tool - it is the ‘head and hands’ of restoration implementation. Native spirituality is the ‘heart’ that guides the head and hands... Cultural survival depends on healthy land and a healthy, responsible relationship between humans and the land. The traditional care-giving responsibilities which maintained healthy land needs to be expanded to include restoration. Ecological restoration is inseparable from cultural and spiritual restoration, and is inseparable from the spiritual responsibilities of care-giving and world-renewal’” (Kimmerer, 2013, p. 336-337).
Dr. Kimmerer is the founding Director of the Center for Native Peoples and the Environment.
References:
Links to Rangeland Restoration:
Links to more Innovative Solutions:
Rehabilitation of rangelands: Working with novel ecosystems
Summaries of the research and commentary by Dr. Delena Norris-Tull, Professor Emerita of Science Education, University of Montana Western,
September 2020.
In rangelands and public lands, some researchers have advocated for recognizing that eradication of invasive species may not be a feasible goal, in restoration or reclamation plans. And that we must consider how to live with a certain level of invasive species, within an ecosystem. What factors leads to this recommendation?
- Many invasive plants were intentionally introduced into the United States. Humans likely will continue to introduce non-native plants into ecosystems, both intentionally and accidentally.
- We may be foolhardy in assuming that we can restore a damaged ecosystem to some idealized historic state, in a manner that does not do further damage. Ecosystems do not sit still. They are constantly changing, and have been changing for eons. We may be mistaken if we assume that we know what a particular ecosystem was like prior to human intervention, or what it would be like now, if humans never had intervened.
- Some plants that we view today as “invasive” or “noxious” have potential benefits for our economy in the future. A number of grasses and forbs were intentionally introduced to the U.S. as livestock forage or as crops. Kudzu is a vine from Japan and Indochina that, in its native lands, is highly valued for food, fiber, and paper production. It was introduced into the Southeastern U.S. as an ornamental vine and for livestock fodder and pasturage. In the 1930s, the U.S. Soil Conservation Service promoted it as a soil binder for use on farmland that had suffered severe soil loss. It has become invasive in much of the Southeast and now covers over one million acres, even growing over forests and obstructing trees from sunlight. But it has potential as an important source of paper and various food and fiber products in the U.S. It may be time to rethink our practice of growing trees to produce paper, rather than using faster growing plants such as kudzu.
- Some invasive species may add resilience to an ecosystem, particularly as changes to the global climate force us to rethink what agricultural products we grow, and where we can grow them.
- It has become increasingly obvious that “eradication,” except in small invasions or on small acreages, is not feasible. We need to ask ourselves the question, how can we co-exist with the non-native plants that we have introduced?
- Attempting to control invasive plants, using herbicides, increased soil disruption, and in some cases, even biocontrol agents, can have unintended consequences that create more problems, and can degrade rangelands and wildlands even more than the invasive species themselves.
DiTomaso, et al., 2017, describe the detrimental effects invasive plants have had in rangeland and natural ecosystems. Invasive plants “can reduce biological diversity, threaten rare and endangered species, reduce wildlife habitat and forage, alter fire frequency, increase erosion, and deplete soil moisture and nutrient levels.” They point out that “invasive plants have been estimated to decrease range productivity by 23-75%..., native plant diversity by 44%, and abundance of animal species by 18%.” In the U.S., “it is estimated that there are over 3000 non-native plant species that have become naturalized and are able to maintain self-sustaining populations within rangelands… However, only 37-60 non-native species are considered of major [detrimental] economic and ecological importance.”
But DiTomaso, et al., 2017, also have found that “in many situations invasive plants provide benefits to the ecosystem.” They propose that, “Such changes [caused by invasive plants] can result in novel ecosystems where the focus of restoration efforts has shifted from preserving the historic species assemblages to conserving and maintaining a resilient, functional system that provides diverse ecosystem service, while supporting many human livelihoods.”
DiTomaso, et al., 2017, point out that “there are trade-offs between positive and negative impacts of invasive plants. This is most apparent in highly altered and degraded landscapes where abiotic conditions [may be] so degraded that native species are unable to naturally recover… even when mediated by restoration efforts.” In those conditions, it may be impossible to restore the ecosystem to an historic ecosystem, assuming that we know what that ecosystem looked like. In those circumstances, invasive plants “may provide a number of beneficial services, including [reducing] soil erosion, regulation of pests and disturbance regimes, purification of air and water, increasing habitat for pollinators and other species, providing nurse sites for native plant establishment, and facilitating phytoremediation…. [Additional services include] livestock or wildlife forage, wildlife habitat,… and medicinal or ornamental value.” Some invasive plant species also help improve soil nutrients.
DiTomaso, et al., 2017, propose that restoration managers “consider other tools, such as state-and-transition models and adaptive management, which provide holistic and flexible approaches for controlling invasive plants, favor more desirable plant species, and lead to ecosystem resilience.” They state that “restoration programs should focus on managing for future change that emphasizes ecosystem function, goods, and services…, maintaining genetic and species diversity, and encouraging biogeochemical processes that favor desirable species… Restoration options that remove the requirement of attaining a historic ecosystem may reduce both the effort and costs, yet may still achieve a desired outcome.”
DiTomaso, et al., 2017, go on to point out that “invasive plant management has often focused on the control of a single species without regard for the unintended consequences of the control method” and without regard for the impact of the control method on the rest of the ecosystem. It is important to examine three primary factors that enable invasive success: “prevailing environmental conditions, traits of the resident species, and traits of the invading species.”
DiTomaso, et al., 2017, suggest that rehabilitating degraded lands may be more beneficial and economically feasible than either restoration (which attempts to restore the ecosystem to some presumed historic condition) or reclamation (which often results in a “monoculture of a highly productive species”). Restoration focuses on increasing biodiversity while reclamation focuses on increased production. DiTomaso, et al., 2017, advocate for attempting the delicate balance between increased biodiversity and increased production.
DiTomaso, et al., 2017, propose that, when dealing with novel ecosystems, rehabilitation, restoration, or reclamation plans be based on intervention ecology, reducing the negative impacts of invasive species through the systematic use of multiple, combined tactics, which may include:
- Identifying the causes of an invasion
- Monitoring the various species that are invading, or potentially invading, the system to assess the cumulative risk, and to prevent invasions where feasible (Early Detection and Rapid Response)
- Integrated pest management (IPM) focused on attention to the impact of the invasion on the entire ecosystem (including biotic and abiotic factors)
- Reduced use of herbicides and tillage (and implementation of other agricultural best practices)
- A holistic approach that recognizes that management of rangeland and public lands requires both short- and long-term planning (which must include collaboration between various State, local, and Federal Agencies)
- Use of successional theory (such as that described by Sheley, et al., 1996)
- Resilience-based management, to “provide physical and ecological conditions that allow the system to be self-sustainable,” and to insure biodiversity
- Study of the interactions between species (native and non-native), to determine the role of groups of species (functional groups), rather than individual species, in sustaining both ecosystems and production
- State-and-transition models (STMs), to identify “potential alternative stable vegetation states…, and the existence of restoration pathways that may potentially reverse transitions between states”
- Flexibility in planning, in the highly likely event that not everything goes as planned
- Reliance on a selection of desired species (both native and non-native) that increase the production value of the ecosystem (e.g., increased forage value), as well as enhancing biodiversity. This is a delicate balance, as increased production may reduce biodiversity, and vice versa.
Indigenous ways of knowing
In her book Braiding Sweetgrass, Dr. Robin Wall Kimmerer, a plant ecologist and a tribal member of the Citizen Potawatomi Nation, provides a glimpse of indigenous ways of knowing about nature and about ecological restoration.
In the chapter, “The Sacred and the Superfund,” Dr. Kimmerer describes the destruction of the land surrounding, and the waters within Onondaga Lake, next to Syracuse, New York. For over 100 years, tons of industrial wastes, sewage, and other sources of runoff, poured into the lake. And she describes the gradual regeneration of the lake, by plants, the waters, and the earth.
“But how can we submit to despair while the land is saying ‘Help’? Restoration is a powerful antidote to despair. Restoration offers concrete means by which humans can once again enter into positive, creative relationship with the more-than-human world, meeting responsibilities that are simultaneously material and spiritual. It's not enough to grieve. It's not enough to just stop doing bad things” (Kimmerer, 2013, p. 328).
“How we approach restoration of land depends, of course, on what we believe that ‘land’ means. If land is just real estate, then restoration looks very different than if land is the source of a subsistence economy and a spiritual home. Restoring land for production of natural resources is not the same as renewal of land as cultural identity. We have to think about what land means” (Kimmerer, 2013, p. 328).
“Restoration is imperative for healing the earth, but reciprocity is imperative for long-lasting, successful restoration. Like other mindful practices, ecological restoration can be viewed as an act of reciprocity in which humans exercise their caregiving responsibility for the ecosystems that sustain them. We restore the land, and the land restores us. As writer Freeman House cautions, ‘We will continue to need the insights and methodologies of science, but if we allow the practice of restoration to become the exclusive domain of science, we will have lost its greatest promise, which is nothing less than a redefinition of human culture’” (Kimmerer, 2013, p. 336).
“A 1994 statement from the Indigenous Environmental Network put it best: ‘Western science and technology, while appropriate to the present scale of degradation, is a limited conceptual and methodological tool - it is the ‘head and hands’ of restoration implementation. Native spirituality is the ‘heart’ that guides the head and hands... Cultural survival depends on healthy land and a healthy, responsible relationship between humans and the land. The traditional care-giving responsibilities which maintained healthy land needs to be expanded to include restoration. Ecological restoration is inseparable from cultural and spiritual restoration, and is inseparable from the spiritual responsibilities of care-giving and world-renewal’” (Kimmerer, 2013, p. 336-337).
Dr. Kimmerer is the founding Director of the Center for Native Peoples and the Environment.
References:
- DiTomaso, J.M., Monaco, T.A., James, J.J., Firn, J. (2017). Invasive plant species and novel rangeland systems. In D. Briske (Ed.), Rangeland Systems: Processes, Management & Challenges: 429-465. Springer Series on Environmental Management. Cham, Switzerland: Springer.
- Kimmerer, R.W. (2013). Braiding Sweetgrass. Minneapolis: Milkweed Editions.
Links to Rangeland Restoration:
- Federal Goals for Rangelands
- Prairie Restoration
- Sagebrush Steppe Restoration
- Revegetation with Native Plants
- Dogs as detectors of noxious weeds
Links to more Innovative Solutions: