Ecological Restoration in a Changing Biosphere

If you were at the MBG Fall Symposium, we want to hear from you! How did the symposium change your perception of restoration? Send us an email at leighton.reid@mobot.org.

On October 8th, Missouri Botanical Garden hosted its 63rd annual Fall Symposium. This year’s theme was Ecological Restoration in a Changing Biosphere. Author and journalist Paddy Woodworth moderated the day, and seven speakers presented contemporary perspectives on a core challenge in modern restoration ecology. Namely: in the post-COP21 world, when all three UN conventions call for scaling up and mainstreaming of restoration, it is clear that restoration will affect hundreds of millions of hectares – and as many people – over the coming decade. At the same time, we find ourselves in an era of unprecedented change where climate, ecological baselines, and future land-use changes are highly uncertain. This raises the question: What should large-scale restoration look like in the remainder of the 21st century?

symposium_group-photo_01

2016 Fall Symposium speakers. From left to right: Peter Wyse Jackson, Curt Meine, Robin Chazdon, James Aronson, Leighton Reid, Pedro Brancalion, Karen Holl, Don Falk, Paddy Woodworth, and Jim Miller. Photo by Andrea Androuais.

Talks during the morning focused on tropical forests, where much of the international restoration dialogue is focused.

  • Leighton Reid (Missouri Botanical Garden) opened with a presentation on restoration longevity – the idea that some restoration projects create ecosystems that persist for more than a century (e.g., Floresta da Tijuca), while other projects fail quickly. Dr. Reid argued that how long restored ecosystems persist is quantifiable, predictable, and manipulable, opening the possibility for more ambitious restoration planning.
  • Robin Chazdon (University of Connecticut and beyond) then spoke about forest landscape restoration, an approach that aims to regain ecological integrity and enhance human well-being in deforested, human-impacted, or degraded forest landscapes. Drawing on a wealth of large-scale studies, Dr. Chazdon made the case that natural forest regeneration is the most ecologically effective and economically feasible approach to forest restoration globally.
  • Karen Holl (University of California Santa Cruz) presented her take on research priorities for forest restoration in the Neotropics. She highlighted that researchers could make an impact by studying forest restoration at larger spatial scales, at longer temporal scales, and in collaboration with stakeholders. Improving information exchange and standardizing monitoring protocols were also among her top priorities. (Graduate students, take note!)
  • Dr. Pedro Brancalion (University of São Paulo) completed the morning session with a TED talk-style discussion of the linkages between science, technology, policy, and best practice in Brazilian Atlantic Forest restoration. Using Thomas Kuhn’s structure of scientific revolutions, Dr. Brancalion argued that restoration ecology is in a crisis period, in part because disciplinary research has predominantly created solutions at smaller spatial scales than the (growing) problems the discipline seeks to address. Perhaps restoration is ripe for a paradigm shift?
rc_pedro

Dr. Pedro Brancalion (right) asks whether restoration ecology is ready for a new paradigm shift, as Paddy Woodworth (left) moderates. Photo by Robin Chazdon.

After lunch, the conversation turned towards a major academic debate in restoration ecology. Has global change outpaced the restoration approach? And is a new approach needed?

  • Curt Meine (The Aldo Leopold Foundation) drew on his long experience in the upper Midwest, and, in particular, his studies of author and environmentalist Aldo Leopold (1887-1948). He argued that Leopold avoided the simple polarities through which some contemporary restoration debates are framed. He viewed nature in a relative way, neither entirely wild, nor entirely domesticated in any given landscape. Although he practiced ecological restoration in some contexts, he also advocated soil conservation and sustainable agriculture – activities motivated by his core values, as expressed in The Land Ethic (1949).
  • James Aronson (Missouri Botanical Garden) followed with an elucidation of the reference ecosystem concept. Reference ecosystems, he noted, help determine the social and ecological vision for a restoration project or program – a critical issue for restoring historic continuity in degraded landscapes. Dr. Aronson described a family of restorative actions for achieving progress towards the reference system, drawing on examples from Jordan and South Africa. He argued we need to look deeper into the past and ponder our choices from many angles as we decide how to do more effective restoration at the landscape and larger scales.
  • Donald Falk (University of Arizona) delivered the keynote address. He painted a disturbing portrait: rapid climate change is driving a massive forest-to-non-forest transition in the southwestern United States. In particular, many ponderosa pine forests will not be able to persist in the future where they have been in the recent past and present. Perhaps restoration ecologists should transition too. Rather than “chasing the ambulance”, maybe we could get out ahead of disasters and ease transitions between stable ecosystem states. Anticipating ecosystem transitions could mitigate the loss of ecosystem functioning that accompanies major climate-driven forest fires, but it would require a shift in restoration thinking. Importantly, Dr. Falk noted that ecosystems do not care what words we use – ecosystems respond to actions.

With moderator Paddy Woodworth’s help, we finished the day with a panel discussion, inviting questions from the audience. Among the thoughts and questions that we were left with:

  • Is ecological restoration more difficult in places with greater population density?
  • Should restoration focus on policy, economic, or cultural motivations for engaging people?
  • Are values a better guide for land management than ecological history? Are the two complementary?
  • How can the reference ecosystem concept accommodate rapid biome changes, as we are seeing in the Southwestern USA?
  • What is the way forward to mainstream serious, multisectorial monitoring and evaluation with all these new factors to consider? Who will fund it?
  • To what extent can we move from restoring degraded ecosystems to avoiding degradation in the first place?
  • Can forest landscape restoration and natural forest regeneration bridge the gap between small-scale, past restoration experience and present, large-scale restoration needs?
rc_lelandricardo

PhD candidates Ricardo Cesar (University of São Paulo) and Leland Werdan (University of Minnesota) compare notes on seedling functional traits in dry tropical forest restoration. Leland was the recipient of the annual Delzie Demaree award. Photo by Robin Chazdon.

mbg63-registrants

More than 150 people registered for the symposium. They came from three continents, five countries, and seven US states.

Environmental determinants of plant community change during restoration at Shaw Nature Reserve

Olivia Hajek spent 10 weeks this summer studying woodland restoration at Shaw Nature Reserve with CCSD scientist Leighton Reid. She participated in MBG’s NSF-funded Research Experience for Undergraduates (REU) program.

WildFlowers

Wildflowers in the restored Dana Brown Woods: purple milkweed (Asclepias purpurescens; left) and buffalo clover (Trifolium reflexum; right).

During my ten weeks in Missouri, I completed a research project evaluating the role environmental conditions play in restoration at Shaw Nature Reserve.  Specifically, I worked in the Dana Brown Woods management unit, a part of the Missouri Ozark foothills that features diverse plant communities across its heterogeneous landscape.  Sixteen years ago, the Dana Brown Woods was a closed-canopy woodland highly invaded by eastern red cedar.  However, restoration practices including reintroduction of fire and mechanical removal of woody shrubs like eastern red cedar have dramatically changed plant communities since 2000.  I was very fortunate coming into this project because there was extensive data about the plant communities in the Dana Brown Woods from 2001-2012 while restoration was occurring.  A local botanist, Nels Holmberg, monitored understory plants beginning a year before the first fire, creating complete information about the plant community before restoration and as it changed over time.

We wanted to see how different environmental conditions affect how plant communities change over time in response to restoration.  To answer this question, we visited 300 points across the woodland and measured several environmental parameters, including aspect, slope, rockiness, elevation, and juniper stump density (juniper stumps decay slowly, so many of the trees cut in 2006 were still visible).

IMG_0049

Fieldwork in Dana Brown Woods. Olivia makes friends with a hog peanut (Amphicarpaea bracteata).

Just from field observations, we could see noticeable differences in the environment and plant community composition across the woodland.  Higher slopes were rockier, covered in old juniper stumps, and rich in sunflowers, whereas the lower regions near the Meramec River floodplain had deeper soil and more mesic plant species, like spicebush.

Data analysis confirmed that environmental gradients moderated plant community change over time. Higher, rockier areas experienced greater plant species turnover and greater increases species richness and abundance from 2001-2012, whereas shaded valleys changed relatively little.

DataPlot

Plant composition change from 2001-2012 increased with elevation, particularly during spring surveys. BC = Bray-Curtis dissimilarity, which measures the difference in plant species composition between a plot in 2001 and itself in 2012. Juniper, red oak, and white oak were subjectively determined habitat classifications at the outset of the study.

Our observations were likely driven by differential fire behavior across the woodland. Historically, fires were a frequent disturbance in the Ozark foothills. Four prescribed fires from 2001-2012 probably had larger impacts on the drier upland areas than in the wet lowlands, which would not have burned as well.

Quantifying how ecological restoration practices, like prescribed fire, vary across environmental gradients is important for land management planning, especially in the Ozark foothills where the landscape is so heterogeneous.

Poster

Leighton stood by while Olivia presented her research to the public at Sensational Summer Nights.

Seed Banking for Conservation and Restoration

Meg Engelhardt is Missouri Botanical Garden’s Seed Bank Manager. She describes her ex situ conservation program and its applications for ecological restoration.

Seeds have been stored for food since the dawn of agriculture, but in recent decades seed banks have become an increasingly relied upon tool for plant conservation. Ideally we would conserve all plants in their natural habitats, or in situ. After all, when plant populations remain intact so do the relationships with other organisms in their ecosystems. Intact plant populations also maintain gene flow within the species, helping populations continually adapt to their surrounding environments. Unfortunately, it is not always possible to maintain wild plant populations. Even when resources are available, maintaining natural plant populations may be impossible due to habitat fragmentation or destruction, range shifts due to climate change, pollinator loss, or any list of known or unknown factors resulting in population decline. This is where seed banking, or ex situ conservation, may play a supporting role.

FranklinCountySeedCollection

Collecting seeds from a dolomite glade in Franklin County, Missouri

Seed banks are long term storage facilities designed to keep seed viable for years and even decades. Those seeds can then be used for research, restoration, reintroduction, or education.

Maybe you have heard of the Svalbard “doomsday” Seed Vault, where seeds of more than 4000 plant species are stored deep below the permafrost near the north pole. Or perhaps the Millennium Seed Bank, which holds 13% of the world’s wild plant species and continues to collect the world’s threatened flora. Here in the United States we have the Native Plant Germplasm System, a network of 20 storage facilities across the country that store over 15,000 species, with a focus on agriculturally important species. On a more local scale, many small seed banks are used to conserve regionally important, threatened species.

NationalCenterGeneticResourcesPres

Inside a very large freezer at the National Center for Genetic Resources Preservation in Ft. Collins, Colorado

The Missouri Botanical Garden has been seed banking for over thirty years. In 1984 the Center for Plant Conservation (CPC) was founded with Missouri Botanical Garden as a founding member. CPC is a network of 40 botanical institutions focused on ex situ conservation of rare plant material while also ensuring material is available for restoration and recovery efforts. Our CPC collection is currently maintained by staff who are actively seed banking, researching, and restoring populations of extremely rare native plants throughout southeastern US (Solidago ouachitensis, for example).

Additionally, seed collecting and short term seed storage has been going on for at least 25 years at Missouri Botanical Garden’s Shaw Nature Reserve. Horticulture staff at the Reserve are focused on local ecotype native plant horticulture and have been collecting seed from regional wild sources for use in small scale greenhouse propagation, use in the Whitmire Wildflower Garden, restoration projects throughout the Reserve, and various other partnerships that encourage native plant horticulture.

SNRSeedCloset

The Shaw Nature Reserve “seed closet” currently houses almost 500 different taxa ‒ most of which are local wild source (i.e., seed collected from plants growing in the wild) or second generation seeds (i.e., the first descendants of plants growing in the wild).

In 2013 the Missouri Botanical Garden Seed Bank was created with two main goals. First to advance seed banking at an institutional level by providing support and facilities. A new seed lab space was created at Shaw Nature Reserve which includes lab benches and space for processing collected seed and cleaning for storage as well as a refrigerator and freezer storage space. The second goal is to collect and store samples of Missouri’s entire flora, which includes roughly 2,055 taxa. Continually collecting and storing samples of all local species will ensure long term genetic conservation that can be made available for research, restoration, and recovery should the need arise.

MOEveningPrimrose

Missouri Evening Primrose, Oenothera macrocarpa

Vegetation changes at Shaw Nature Reserve

CCSD scientists Leighton Reid, Matthew Albrecht, and Quinn Long are teaming up with restoration ecologist James Trager and botanist Nels Holmberg to learn how ecological restoration has affected herbaceous plant communities in an eastern Missouri woodland.

What happens to Missouri’s grasses and forbs when you remove invasive shrubs? When you return prescribed fire to a degraded woodland? How do restoration impacts differ for summer-blooming plants and spring ephemerals? For dry hilltops versus mesic hollows? These are a few of the questions that we hope to address with a long-term dataset from Shaw Nature Reserve.

IMG_0101-001

Nels Holmberg (left) and Quinn Long (right) discuss the finer points of blackberry identification at Shaw Nature Reserve.

Shaw Nature Reserve encompasses 10 km2 of woodlands and glades along the Meramec River in eastern Missouri. Missouri Botanical Garden purchased the land in 1925 when coal pollution in Saint Louis was so bad that it was killing plants; the garden decided to move its collections to the country where the air was pure. Ultimately the city cleaned up, the collections stayed in Saint Louis’s Tower Grove neighborhood, and the property along the Meramec became a nature reserve and popular hiking area.

Like other ecosystems in the Missouri Ozark foothills, Shaw Nature Reserve changed considerably during the last century. Fire, once a regular disturbance, became scarce, allowing junipers to crowd in on the glades. Invasive species, like Amur honeysuckle, spread into the woodlands and created dense, understory thickets.

blue wood aster (Symphyotrichum cordifolium)

Blue wood aster (Symphyotrichum cordifolium) – a late bloomer in the Dana Brown Woods.

Twenty five years ago, Shaw Nature Reserve began to counteract these changes through ecological restoration. Staff and volunteers cleared invasive shrubs and began to periodically burn the landscape.

In 2000, restoration ecologist James Trager and botanist Nels Holmberg designed a study to monitor restoration effects on herbaceous vegetation. Holmberg surveyed 30 transects twice per year from 2000-2012, recording the abundances of more than 360 plant species. Restoration in this area started in 2003, so the first two years of Holmberg’s transects represent a pre-restoration baseline against which we can compare data from the subsequent decade.

OLYMPUS DIGITAL CAMERA

Holmberg’s dataset contains more than 50,000 rows. Thanks to Christian Schwarz for digitizing them!

Recently, we plotted Holmberg’s transects on Google Earth. The images show clear changes since restoration began almost 15 years ago.

DBW1995

Holmberg’s transects transposed on a 1995 aerial photo of Shaw Nature Reserve – zoomed in on the Dana Brown Woods. This photo was taken in early spring before most trees leafed out. Dark vegetation is predominantly eastern red cedar (Juniperus virginiana). Holmberg originally grouped the transects into three classes based on the dominant vegetation.

NelsAug2005

Juniper clearing began in 2006. This is what the summer-time forest looked like the year before…

DBW2006

…and after juniper clearing. By 2006 the Dana Brown Woods had been burned twice with prescribed fires, and a lot of the junipers had been cut out. Compare the open/brown areas in this photo with the solid green canopy in 2005.

DBW2014

The most recent imagery, from October 2014, shows some fall color. Note that “red oak” mostly refers to upland Shumard oak, Quercus shumardii.

Our plan for 2016 is to analyze changes in understory vegetation composition over twelve years. Stay tuned for more information in this ongoing project!

Can the Ozark chinquapin successfully re-colonize interior highland forests?

Jenn Rosen is an undergraduate at the University of Missouri – Saint Louis. This summer, she participated in the Missouri Botanical Garden’s Research Experience for Undergraduates (REU) program. She spent eight weeks working with scientists in the Center for Conservation and Sustainable Development. Here, Jenn writes about her field experiment at Shaw Nature Reserve.

Conservationists and ecologists have recently sought to restore an ecologically important tree, the Ozark chinquapin (Castanea ozarkensis), that became threatened not by the effects of clear-cutting, but instead due to an incurable parasitic fungus called chestnut blight (Chyphonectria parasitica). After devastating its cousin (American chestnut) in eastern forests, the fungal disease moved west and began infecting chinquapin trees in the Ozark and Ouachita Mountains. The blight is presumed to have been brought into the United States by accident in the early 1900s when Chinese chestnuts (C. mollissima) were imported into the country. What makes the Ozark chinquapin and the American chestnut so susceptible to the disease is that the fungus’ wind-borne ascospores can easily enter through small cavities in their bark where they then grow and spread to neighboring trees. The blight causes Ozark chinquapin trees to die back to the roots, from which multiple stems resprout to form a large shrub-like growth form. Once a widely dispersed canopy tree in upland Interior Highland forests, chinquapins declined in abundance and are now often found as multi-stemmed, blight-infected subcanopy shrubs.

Castanea ozarkensis seeds from two maternal lines. One group's seeds are twice the size of the others. Large seeds hold more resources, which can give seedlings a head start. But larger seeds also face a higher risk of being preyed upon by rodents.

Castanea ozarkensis seeds, with white radicles, from two maternal lines. One group’s seeds are twice the size of the others. Large seeds hold more resources, which can give seedlings a head start. But larger seeds also face a higher risk of being preyed upon by rodents.

Chinquapins were prized by many folks of the Ozarks for the nutrient-rich nuts they produced, and its rot-resistant woods were used to make furniture, railroad ties, and fence posts, among other products. Additionally, large mammals such as black bears were known to forage in the Ozarks in search for the nutritious nuts to help replenish their fat reserves for the upcoming breeding season. There is a collaborative effort among groups to restore the chinquapin throughout its’ former range once blight-resistant seeds become widely available, estimated to take approximately 20 – 30 years.

Once blight-resistant seed becomes available, understanding how chinquapin trees successfully regenerate in the wild will be the key to successfully restoring this species. Unfortunately, little is known about the ecology of the tree prior to blight infection. Like other nut-bearing trees in Ozark woodlands (e.g., oaks), we suspect that there may be several limiting factors to chinquapin seedling recruitment, such as seed predation, poor soil quality and/or poor light availability. In order to test these predictions, we planted 320 chinquapin seeds (from two distinct maternal origins from the wild) across ten experimental replicates at the Shaw Nature Reserve (Gray Summit, Missouri). The criteria for each replicate was that there had to be a shrub microhabitat, which was dominated by the common understory tree, eastern redbud (Cercis canadensis), and an open habitat, separated by at least three meters. Like other Ozark woodlands, prescribed fire is currently being used to restore woodlands at the Shaw Nature Reserve and will likely be a key component to successfully reintroducing chinquapins back into the wild. After enduring many scrapes and pricks from constructing mammal exclusion cages for half of the seeds, roughly two weeks after planting the seeds we had a bounty of little chinquapin seedlings emerge.

Castanea ozarkensis seedling, protected from marauding rodents by a wire cage.

Castanea ozarkensis seedling, protected from marauding rodents by a wire cage.

We found that consumer treatment and microhabitat structure, as expected, influenced the rates of Ozark chinquapin seed emergence. Nearly all of the seeds that were exposed to small mammals were eaten or removed, even though seeds were buried a few centimeters in the soil. Interestingly, small mammals consumed seed at greater rates in shrub than open microhabitats. These results imply that understory vegetation structure determines where chinquapin seedlings can successfully recruit through its influence on small mammal behavior. Also, small mammals removed larger, and presumably more nutritious, seed at greater rates than smaller seed. Environmental factors, like light availability, did not affect seedling growth, but the short duration of the study may not have been adequate for the potential influence of these factors to become apparent.

Our work contributes to a larger ongoing project by the Ozark Chinquapin Foundation to restore and conserve Ozark chinquapins. Given the high rates of seed removal, future restorationists will have to transplant chinquapin seedlings as opposed to seeds to successfully reestablish this species in the wild. However, once reintroduced seedlings grow to maturity and produce seed, our study suggests that microhabitat structure in Ozark woodlands will play a key role in determining the recruitment and growth rates of restored populations.