|09:00 am - Novel Ecologies|
Between human disturbance and climate change, every environment on the planet is being affected by humanity. Will we ever get out from under all the weeds we’ve introduced? As the scope of our effect on the planet becomes larger, biologists and ecologists have begun to talk about “novel ecologies.” a concept that would accept some level of disturbance in order to bring successful restoration within reach.
Ecological restoration is the act of taking a degraded landscape and restoring it to a fully-functioning ecosystem. Examples of degraded landscapes would be a mine site, an estuary that was used as farmland, or decommissioned alpine trails and camping sites. In North Beach Park, we’re working on a patch of degraded urban forest and wetlands. It’s considered “degraded” because, when we started restoration, there was a lot of trash from the ravine being used as a dump, the canopy cover was mostly short-lived alders and big leaf maples, and the groundcover was becoming increasingly dominated by English ivy and blackberry.
Restoration in this urban park is largely being done by removing invasive plants and introducing native plants, hopefully resembling a pre-disturbance plant community well enough that it will restore the functions that it lost. North Beach Park lost diversity and functions in at least four areas: (1) root structure which holds the soil and filters water for the stream and wetlands in the park; (2) bloom times to provide food for birds, bees, and insects and those who eat them; and (3) canopy structure which provides habitat for different birds; (4) carbon sequestration provided by long-lived conifers.
But what is invasive, what is native? Whenever humans arrive in a new place, we begin introducing new species and making things less hospitable for plants and animals that lived there before us. Do we want to restore an urban park to a status it had before any human disturbance? In the Pacific Northwest, the Salish people were living here as soon as the glaciers retreated – following the glaciers north, in fact. Later, Europeans brought a whole slew of disturbances.
The Washington Native Plant Society defines a native plant as:
“…those species that occur or historically occurred within the state boundaries before European contact based upon the best available scientific and historical documentation.”
The scientific and historical documentation happened in the early and middle 19th century, but there had already been two disruptions: Beaver trapping had already greatly reduced the beaver population, disrupting river cycles; and smallpox had already reduced the human population, disrupting such cultural practices as burning to maintain open prairies. However, neither of these disruptions had nearly the impacts that occurred with settlement, agricultural development, and logging, which started around 1850.
The 19th century botanical documentation was done with an eye toward finding new plants for the British horticulture industry, not towards understanding plant interactions and communities. We get that understanding from late 20th and early 21st century practices of looking back through the historical records or studying relict patches that, as best we can determine, exist in nearly untouched conditions.
Noteworthy examinations of relict patches in the Pacific Northwest were done by Christopher Chapell (forest plants) and Linda Kunze (low-lying freshwater wetlands). Examination of the historical record was done by Ray Larson in his MS thesis, which examined the botanical records of the federal land surveyors.
Establishing nativeness for plants is difficult. Sometimes, introduced plants that “play well with others,” or are useful or attractive to humans, are considered “native.” Sometimes a species that was growing in an area prior to human disturbance is released from competitive pressure, expands its range, and we decide it’s “invasive.” You’ll never see stinging nettle or western dock on a planting list, for instance.
The documentation of historic conditions in Washington was more recent and the disruption less drastic than in other areas. In many other places in the United States, the disruption by European immigrants happened quickly and with no records at all of pre-existing conditions.
The difficulty of knowing pre-disruption conditions and uncertainty of the nativeness of plants and wildlife, and the difficulty of eradicating all the invasive species (honeybees and earthworms would be impossible to eradicate in the Pacific NW, let alone ivy and blackberry), has led some biologists to propose the concept of “novel ecologies”. That concept has since been a point of contention among invasion biologists for about 20-30 years. The idea is that some areas are so disrupted or degraded from their original conditions that they could never be restored to pre-disturbance states. Novel ecologies would allow restorationists to set some reasonable level of acceptable disturbance that would bring successful restoration within reach.
But, in my opinion, the idea of novel ecologies is too broad and too facile.
Too broad because, wherever humans are, we create a novel ecology compared to pre-settlement conditions. Too facile, because it can too easily serve short-term human purposes. Does the government want to widen river buffers from 50 to 100 yards, which would take away acres of your Christmas tree farm? You, the tree farmer, would then show that your farm is a “novel ecology” and thus protected from change.
However, we can use the idea of novel ecologies to examine our restoration efforts. If all cities are novel ecologies, should we accept them as they are or engage in restoration? What can we do to restore, rehabilitate, or reintegrate some of the functions that we’ve disrupted? Cities were built in forests; we turned the forests into areas of dense buildings interspersed with islands of parks and gardens with pretty but non-native plants. Do we want more of a forest here in the city? What can we do to allow the city to have viable forests within its perimeter?
Two books that talk about novel ecologies from a general perspective:
Rambunctious Garden: Saving Nature in a Post-Wild World, Emma Marris. (My review here.)
Where Do Camels Belong?: Why Invasive Species Aren’t All Bad, Ken Thompson.
Two articles that look at the concept as well:
‘New normal’ approach to conservation comes under fire by Jose Hong. This article discusses a peer-reviewed critique of the idea of novel ecologies.
Thoughts on the “New Nature”: Are Collared-Doves dangerous invaders or just birds? by Alan de Queiroz. Another article that looks at the idea of novel ecologies, discussing “Where Do Camels Belong?”, “The Urban Bestiary” (Haupt) and other books.
This article was edited by Jean Davis. All mistakes and infelicities remain with the author, me.
Mirrored from Nature Intrudes. Please comment over there.