“Ecological Restoration and Environmental Change”

Green Oaks, Knox College
Green Oaks, Knox College

Restoration and Environmental Change:  Renewing Damaged Ecosystems was written by Stuart Allison.  He is Professor of Biology and Director of Green Oaks Field Study Center at Knox College in Illinois.  His perspective on ecological restorations is unique because he is both a scientist and actively engaged in ecological restoration. 

There is a predictable tension between applied and theoretical science.  Ecology is particularly susceptible to this tension because its application is usually considered the immediate goal of the theoretical science that is intended to inform and guide it.  Therefore, we were very interested in Professor Allison’s viewpoint and we were intrigued by the suggestion of his title that his book would take into consideration the rapidly changing environment.

Although the restoration goal at Green Oaks is the re-creation of the tall grass prairie that is the historical landscape, Allison’s Ph.D. degree from UC Berkeley in Integrative Biology suggested that he is also familiar with our local ecology in the San Francisco Bay Area.  In fact, he mentions our controversy regarding the desire of native plant advocates to eradicate eucalyptus in California and he uses it to illustrate his opinion of novel ecosystems.

“When I was a graduate student at the University of California, Berkeley there was (and still is) a magnificent grove of blue gum (Eucalyptus globulus) outside of the Life Sciences Building.  It was rumored that they were some of the tallest blue gums in the world, growing so tall because they lacked any herbivores and diseases.  Eucalyptus trees grow beside roads all along California’s coastal highways and in the inland valleys of the coast ranges.  In fact, I cannot imagine California without eucalyptus trees.  But, of course, eucalyptus are not native to California–the first eucalyptus was introduced to California by Australian miners coming to the Gold Rush in the 1850s.  Today eucalyptus are so well established that many people think they are native to California, and even if they know they are not native, they don’t want to see them removed because to them, like me, eucalyptus are a central part of their experience of California.  Some people also fear that removal of eucalyptus will lead to erosion on steep hillsides and a decline in biodiversity.  In contrast, native plant enthusiasts in California would love to see eucalyptus permanently removed.  The dominance of eucalyptus in California is hardly unusual for a novel ecosystem, but it stands out because the trees came from Australia and because they are so striking in appearance and aroma that they can’t be missed.” (1)

Professor Allison then acknowledges that some scientists are now interested in and respectful of novel ecosystems such as the eucalyptus forest.  However, he is worried “that novel ecosystems will lead to a homogenized world in which the same species…are found everywhere.”   That debate is not the central theme in his book.  His primary objective is to take the pulse of his colleagues in ecological restoration and report the changes in their objectives in the past 20 years, given the rapid changes that have occurred in the environment.

What is the goal of ecological restoration?

The Society for Ecological Restoration (SER) is the professional organization recognized by most restorationists.  Its Policy Working Group claims that “an ecosystem is fully restored and the project has been completed when the restoration ‘contains sufficient biotic and abiotic resources to continue its development without further assistance or subsidy.’”

Annual Prairie Burn, Green Oaks, Knox College
Annual Prairie Burn, Green Oaks, Knox College

Professor Allison tells us that the restoration in which he has been engaged for over 20 years will never achieve that standard:  “The tall grass prairie and savanna restorations I work with are all based on a return to historical pre-Euro-American disturbance, but all require perpetual management and human intervention to maintain them on the desired ecological trajectory.  Without regularly applied fire, those ecosystems would soon become dominated by many woody species and grow into a woodland lacking prairie or savannah characteristics.”  Professor Allison describes the annual “Prairie Burn” at Green Oaks which is considered an important social event by students at Knox College.

This is one of many ironies about ecological restorations.  Many projects are attempting to re-create an historical landscape at a specific period of time, which was not the result of natural succession.  In the case of grassland prairie, it was largely the result of periodic fires set by Native Americans.  Left to its natural devices, grassland would soon be “invaded” by shrubs and over time it would become a forest if soil and climate conditions were suitable.  In that sense, it is an artificial landscape, as unnatural as any manmade garden.  That the humans who created that historical landscape were indigenous, as opposed to European settlers, seems to us a meaningless, legalistic quibble.

The “field of dreams” theory

Most restoration projects focus almost entirely on plants.  Little explicit attention is paid to the animals that are the desirable inhabitants of the restoration.  Restorationists believe that if the habitat is made available, the animals will quickly follow.  This is the “field of dreams” theory, i.e., if we build it, the animals will come.   This is magical thinking.

Restoration projects rarely monitor the results of their projects sufficiently to test this theory.  In the San Francisco Bay Area, native plant advocates claim there are more birds and animals occupying restoration sites, but these are anecdotal observations that cannot be verified.  Nor do they seem credible to skeptics of the projects, who often think the habitat that has been eradicated actually supported more wildlife. 

Evolving goals of restoration projects

Here in the San Francisco Bay Area we have observed the changing objectives of ecological restorations.  Over fifteen years ago, local projects were touted as “sustainable.”  The public was told that once restored to historical equilibrium conditions, the projects would be capable of sustaining themselves without further resources. 

Comparson of pesticides used by San Francisco's "Natural Areas Program" compared to landscaped areas of San Francisco's parks
Comparson of pesticides used by San Francisco’s “Natural Areas Program” compared to landscaped areas of San Francisco’s parks. Photo courtesy of SF Forest Alliance.

We no longer hear that claim.  Now we are told that our “natural areas” must be managed in perpetuity.  More herbicides are used in San Francisco’s “natural areas” than landscaped portions of the parks, with the exception of a professional tournament golf course.  And if we want the animals that historically occupied those areas, they must be reintroduced, using labor-intensive methods.

Professor Allison observes the same “mission creep” amongst his colleagues.  The goal of replicating an historical landscape is no longer the dominant theme of ecological restorations.  Now the goal is more commonly defined in terms of increasing “biodiversity” and improving “ecological functions.”

New buzz words

If the new goal of ecological restorations is greater biodiversity and improved ecological functions, it seems reasonable to ask what these terms mean.  Unfortunately, we were unable to find the answer to that question in Professor Allison’s book.  Those terms are used as though their meanings are intuitively obvious.  They are not.  These terms are jargon that has little intrinsic meaning and they probably mean different things to different people.

When scientific studies quantify biodiversity, they count species of both native and non-native plants and animals.  Since there are now far more species of non-native plants and animals and far fewer extinctions of native plants and animals, biodiversity has increased virtually everywhere in the world.  So, as far as science is concerned, how could a restoration project that eradicates all non-native species result in greater biodiversity?

Obviously native plant advocates are defining the word “biodiversity” differently than traditional science.  Native plant advocates seem to define biodiversity as exclusively native.  Furthermore, the nativist ideology believes that the mere existence of non-native plants and animals will inevitably result in the extinction of native plants and animals.  There is little scientific evidence to support this assumption.  Few extinctions have been attributed to the existence of non-native plants and no extinctions blamed on non-native plants have occurred in the continental United States.

The term “ecological functions” is even more mysterious as it relates to ecological restorations.  It could mean almost anything:  production of biomass, soil composition, photosynthesis, carbon sequestration and storage, nutrient cycling, fire regime, hydrologic cycle, etc. 

Professor Allison does not provide us with his definition of this term, so we will make an assumption based on our knowledge of ecological scientific literature.  We told our readers about a study in Hawaii which compared native and non-native forests with respect to the ecological functions they are performing.  In that study, three such functions were measured and reported:  carbon sequestration, production of biomass, and nutrient cycling.  The study concluded that non-native forests were performing these ecological functions as well as native forests. 

We can also compare treeless grassland prairie with a native or non-native forest with respect to those ecological functions.  Forests—whether native or non-native– will fulfill these and other functions at least as well as the grassland prairie.  If we add the factor that the grassland prairie must be burned annually to maintain it, clearly the grassland prairie is an ecological deficit because it releases pollutants and greenhouse gases into the atmosphere when it is burned.

The moving target

The goals of ecological restoration are a moving target.  The original goals of re-creating an historical landscape that would be sustainable without continual maintenance are now widely acknowledged to be unrealistic. 

The new goals are equally elusive.  The new goals are described in obscure ways that will be impossible to measure or evaluate.  That suits the purposes of native plant advocates perfectly.  They can continue to do whatever they want and the public can’t hold them accountable because the public is not provided with a practical method of measuring success or failure.  

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(1)    Stuart K. Allison, Ecological Restoration and Environmental Change:  Renewing Damaged Ecosystems, Routledge, UK, USA, Canada, 2012