A guest post from PLOS Ecology Reporting Fellow, Liz Kimbrough, on research from the Ecological Society of America Scientific Meeting in Ft. Lauderdale, Florida, August 7-11, 2016.
To the novice, restoration may sound like a gentle term. A child’s tiny hand holds a tender green seedling before placing it in the ground. A kindly old farmer leaves a corner of his pasture to time where it grows into a shady oasis for birds and butterflies. But researchers and land managers involved in on the ground restoration projects paint an entirely different picture: one that often involves intense, almost drastic measures–large scale herbicide treatments, heavy logging, stirring the soil with machines, and trial by fire. At the Restoration Ecology I session of the 2016 Ecological Society of America conference, a theme emerged: the sheer intensity of work required to transform and often to maintain a restored landscape.
South of this year’s ESA conference, in the Florida Everglades, Dr. Sue Newman of South Florida Water Management and her team battle a dense onslaught of invasive cattail (Typha) that are fertilized by agricultural runoff. While cattails choke out the native ecosystem, they also provide a service. “In these enriched areas where soils have high phosphorus concentrations,” says Newman, “cattail grow rapidly and take up nutrients, protecting the areas downstream.”
Newman and her team set out to determine whether restoration could be “jumpstarted” removing just enough cattail to create open plots while retaining a cattail buffer. Plots were burned, sprayed, and kept open for years. The results: the dissolved oxygen content rose and birds began to visit the plots, drawn in by the fish, which thrive in these more open areas. Her team concluded that an alternate regime has been created and can be “sustained” but only with careful management.
The theme of this year’s ESA conference, “Novel Ecosystems in the Anthropocene” came across clearly in this session; as novel ecosystems have long been an outcome of restoration projects. One category of land ripe for the creation of novel ecosystems are abandoned agricultural lands which, according to Nash Turley of Michigan State University, cover 747 Rhode Islands worth of the earth’s surface. It is well established that agriculture leaves a legacy. After 2000 years, we can still see effects from Roman agricultural practices. So Turley wondered, how do these agricultural legacies influence biodiversity?
In a recent Ecology paper, Turley and Brudvig posed an equally interesting question: how should we measure biodiversity in the first place? Traditionally, species richness (the number of different kinds of species) and community composition are used by restoration ecologists, but Turley and Brudvig make a strong case that phylogenetic diversity is also an important and overlooked component of biodiversity analyses.
Turley and Brudvig examined remnant, longleaf pine savannas as well restored, post-agricultural plots and found that the two land types were equally species rich, but the composition and phylogenetic diversity were vastly different. The restored site, says Turley had “255 million years less diversity then what you would expect given richness.” Their conclusion: post-agricultural legacies are stubborn.
Dr. Paul A. Schmalzer of NASA found that 23 years after the restoration of a citrus grove in Florida, his study site has shifted to become a place where native scrub oaks are important, but exotic grasses still dominate, yet another case of the novel ecosystem.
Restoration studies can also yield surprising results. During her master’s research at the University of Waterloo, Patricia Huynh found that in southern Ontario, cattle exclusion (building fences to keep cows out of streams) did not correlate with improved water quality. And Dr. Ryan P. Walsh, of The Toledo Zoo found that the endangered Karner blue butterfly (Plebejus melissa samuelis) is dependent on, of all things, site temperature.
Sometimes, the surprising result is ending up with a clear recommendation for land mangers. For the blue butterflies, Walsh was able to say that high mature Lupin density is usually associated with butterfly occupancy so land managers can be on the lookout for these areas. For Dr. Betsy Von Holle of the University of Central Florida and her team it was an answer to the question: when should we burn?
The heathlands of the Cape Cod region depend on fire to regenerate and Dr. Holle tested the efficacy of burning during different seasons. Their prescription to land managers: burning in the spring in areas with continuous ground cover and transplanting seedlings into plots.
The management of invasive species is also a monumental issue in restoration. Amanda Knauf, of University of Hawaii at Manoa investigated a restoration technique that aims to give native plants a competitive edge by lowering soil nutrients (invasives typically fare better in high nutrient environments) by adding sawdust to the soil. Though uses for this restoration technique may be species or community dependent, her greenhouse work yielded good results for natives. Her recommendation to land managers wanting to implement this on a larger scale is to remove the invasive species, turn them into sawdust and apply to the ground.
Back on the mainland in the Albany Pine Bush preserve of New York, by the 1990’S, black locust (Robinia pseudoacacia) trees had invaded and only a few isolated stands of native pine bush habitat remained. In 1999, an intensive restoration project was launched and all of the locust trees were cut. Because black locust trees are nitrogen-fixers (meaning the put nitrogen, an essential element and plant nutrient, back into the soil), Dr. Jeffrey Corbin of Union College and his colleagues were curious about what happened to nitrogen dynamics after this land was restored. Using the Up-Goer Five challenge (a technique which uses the 100 most commonly used words to explain big ideas) Dr. Corbin delivered his results: “Getting rid of trees that don’t belong can make dirt less rich.”
So how do we go about restoring these brave new landscapes? One technique discussed by presenter Dr. Leighton Reid of the Missouri Botanical Garden used applied nucleation. In this technique, clusters of trees are planted across the site in clumps instead of covering the deforested area in a grid. These “tree islands” serve as an activation energy of sorts. The growing trees shade out competing plants and attract frugivorous (fruit-eating) birds that disperse more tree seeds. During his talk, Reid discussed his research on epiphytes (plants that live on plants). He wondered, what landscapes and configurations of trees are better for epiphyte restoration? Not surprisingly, his team found that Tropical forest restoration enriches vascular epiphyte recovery. Tree planting doubled epiphyte richness. Interestingly, the plots replanted using applied nucleation techniques were as equally effective as plantation style planting covering the entire plots. Reid plan to discuss this and much more during a symposium this October titled: Ecological restoration in a changing biosphere.
This #ESA2016 session made it clear that Restoration Ecology is a diverse, dynamic field ripe with possibilities for novel research and planet changing potential.
Liz Kimbrough is a PhD student in the Van Bael lab at Tulane University. You can find her in New Orleans studying the microbial communities of bald cypress trees, writing about science, and playing her washboard. Though she hails from Alabama, Liz earned her Bachelor’s in botany amongst the redwood trees at Humboldt State University. Liz discovered a passion for bringing science and environmental news to the public when she began writing for mongabay.org in 2012. Liz is currently a NSF Graduate Research Fellow and is excited to continue communicating science to the public and working in coastal and tropical ecosystems. (Follow Liz on Twitter @lizkimbrough_ )