From Plant Press Vol. 16 no. 3, July 2013
By Gary A. Krupnick
The National Museum of Natural History (NMNH) and the United States Botanic Garden (USBG) jointly hosted the 2013 Smithsonian Botanical Symposium in Washington, DC, this past spring, featuring the theme “Avoiding Extinction: Contemporary Approaches to Conservation Science.” With presentations from seven invited speakers, a poster session, and an award for excellence in tropical botany, the attendees were presented with history, practices, and lessons in modern conservation biology.
The Symposium kicked off on April 19 with a poster session and opening reception at the U.S. Botanic Garden. Fourteen posters presented by professors, students, horticulturists, land managers, and citizen scientists graced the Conservatory at the Garden. The posters featured a wide-range of botanical and conservation topics, such as the history of a federally-listed species, the propagation and restoration of rare plants, best practices for classroom education, and lessons in interpretative displays of endangered species.
The José Cuatrecasas Medal for Excellence in Tropical Botany was presented by Laurence Dorr to Ana Maria Giulietti Harley of Universidade Estadual de Feira de Santana, Bahia, Brazil. Giulietti was recognized for her expertise in her research of the flora of Brazil. She remarked that she was “happy and proud to be chosen among so many other botanists that contribute to tropical botany.” She accepted the award “in the name of the taxonomists and students of Brazil.”
Symposium moderator, Gary Krupnick, head of the Plant Conservation Unit in the Department of Botany introduced the first speaker. Scott Wing, Curator of Fossil Plants in the Department of Paleobiology, NMNH, gave a talk entitled “What Does Past Global Warming Tell Us about Future Plant Conservation?” Wing explained that the most comparable past event to today’s current global warming occurrence is the Paleocene-Eocene Thermal Maximum (PETM), an extreme spike of warmth 55.8 million years ago at the beginning of the Eocene epoch. During the PETM, an enormous sudden release of carbon resulted in the rising of global temperatures 4 to 8°C over a period of 10,000 years and lasted 200,000 years. Possible causes for the carbon increase are methane release, burning of peat, volcanic activity, and permafrost thawing. During his presentation he showed examples of the effect of the PETM on terrestrial ecosystems by looking at the fossil record from the Bighorn Basin in northwestern Wyoming. He explained that leaf margin analysis on fossilized plants shows that the proportion of species with smooth margins to toothed margins increased with temperature. Leaf area also increased with increasing precipitation.
The PETM floristic change included four distinct groups: (1) plant species that went extinct at the beginning of the PETM; (2) plants that were present only during the PETM interval; (3) plants that appeared right after the PETM event; and (4) plants that were common before and after the PETM, but not during the event. At the onset of the PETM, there were local and regional extirpations of temperate deciduous plants (e.g., dawn redwood, birch, sycamore, katsura), and immigration of Fabaceae and other dry tropical plants. At the PETM recovery, there were local and regional extirpations of Fabaceae and other families (i.e., return of the “natives”), and intercontinental immigration of temperate plants. What was surprising, according to Wing, is that there is little evidence of massive extinction. Wing concluded his talk with a few lessons from the PETM story as it relates to the current events of today: Global warming is happening and will continue for many millennia to come – the world will never be the way it was, even in the recent past. Local floristic changes will be severe. Many plant populations might survive a large temperature increase if the rate of dispersal is high relative to the rate of warming. Wing urged that more records of past climate and floristic change are needed with much finer time-resolution.
The next two speakers tackled the subject of invasive species, with very different conclusions. First was Stephen Weller, University of California at Irvine, whose talk was entitled, “Conservation on Oceanic Islands: Interactions between Introduced Ungulates and Invasive Plants.” Weller began by explaining why island endemic species are highly susceptible to the threat of invasive species. Hypothesized reasons include that native species are highly susceptible to grazing, unlikely to withstand pathogens, and have an increased palatability. He then shared his experiences using two different conservation approaches: a focus on a particular species, and a study at the community level.
Weller presented his work with Schiedea adamantis, a species that occurs in a single population on Diamond Head Crater in the middle of Honolulu. His interest in this species stems from his work on the population biology and evolution of breeding systems in Schiedea—a diverse lineage endemic to the Hawaiian Islands. In the past 15 years he has seen the S. adamantis population decline from 267 flowering individuals in 1987 to four flowering plants and 19 smaller plants in 2012. After one unsuccessful restoration attempt, he tried again, transplanting seedlings grown in a greenhouse to a site with remnant native vegetation and a source of water for irrigation. The plants have done well. The next question is whether habitats into which these plants have been placed can sustain a dense enough population.
The first study system at the community level is the dry forest community in the Ka`upulehu Preserve on the island of Hawai`i, which has been invaded by the competitive and fire-promoting fountain grass, Cenchrus setaceus. Weller asked whether restored ecosystems are sustainable through natural successional processes and without continued human intervention. After a baseline survey of the preserve to measure change, Weller’s team studied the effects of fountain grass removal. They found that the removal of key alien species may have beneficial effects for native species, but they also found the rapid expansion of additional alien species. Weller concluded that the dry forest ecosystem has been altered to the extent that an equilibrium is no longer possible, which will require ongoing preservation efforts. In the second study system, the removal of introduced ungulates in the mesic forest of Mahanaloa Gulch reduced the mortality of both native and alien species, but alien species increased in frequency relative to natives. Ungulate exclusion favored mat-forming alien species that impede germination of native plants. Weller’s studies suggest that active restoration is necessary to conserve rare understory native species.
Scott Carroll, Director, Institute for Contemporary Evolution and an ecologist in the Department of Entomology at the University of California at Davis spoke afterwards. Carroll introduced the concept of “Conciliation Biology: The Eco-evolutionary Management of Permanently Invaded Biotic Systems.” Conciliation biology is an integrated approach to the management of biological systems that incorporates invasive species by predicting and managing the outcomes of dynamic native-nonnative interactions. In this strategy, invasive species that provide benefits should not be eradicated, which contrasts with Weller’s study of active restoration.
He began his case by explaining how rapid evolution should be a part of conservation planning, using as examples insects that have adapted to insecticides and plants that have developed resistance to herbicides. Carroll argued that many nonnative organisms are present throughout the world, that these nonnatives often provide services, that eradication of these nonnatives is not a simple fix, and that rapid evolution generated by the native-nonnative interaction offers solutions. He then discussed several case studies of complex consequences of eradication efforts, such as the attempted removal of European rabbits from Australia with the myxoma virus.
Then he described rapid evolutionary assessment programs by speaking about soapberry bugs, which are seed predators on the Neotropical balloon vine, Cardiospermum grandiflorum (Sapindaceae). In the past 30 years, the balloon vine has spread throughout eastern Australia, leading to the rapid evolution of beak lengths in soapberry bugs as a response to their exploitation of the introduced sapinds. Immediate eradication of the invasive vine would have diverse unintended consequences on the bugs, since they have adapted to the exotic species. Carroll therefore argues for a focus shift from acute to chronic effects and management, using proactive, experimental, and process-oriented approaches.
The afternoon session began with Andrea Kramer, Executive Director, Botanic Gardens Conservation International and conservation scientist at Chicago Botanic Garden. Her presentation, entitled “Getting Plant Conservation Right: Successes, Challenges, and Opportunities for the Future,” provided a comparison of the national framework of the Plant Conservation Alliance (PCA) with the targets set by the Global Strategy for Plant Conservation (GSPC). PCA is an association of ten U.S. federal land-managing agencies and nearly 300 non-government organizations. GSPC is a program of the Convention on Biological Diversity aimed at halting the continuing loss of plant diversity. Both programs are not just about threatened species, she explained, but about building policy, funding, training, research, and infrastructure that will prevent a common species from also becoming rare.
Kramer organized her presentation around eight priorities: species inventory, species distribution data, conservation status of species, plant conservation research and policy (e.g., CITES, Endangered Species Act), in situ conservation, ex situ conservation, and education. With each priority, she presented various challenges and opportunities to overcome those challenges. For instance, limited funding is available to maintain and update the conservation status of plant species; however, an opportunity exists in citizen science and rare plant monitoring. In terms of conservation policy, plants listed under the Endangered Species Act are only protected on federal lands (not private lands), and even though they make up to 60 percent of the species listed, plants only receive 4 percent of federal funding. An opportunity does exist in which 32 states have some level of additional protection for listed plant species.
Kramer concluded her talk by acknowledging the great strides that the U.S. has made in describing the flora, assessing the flora’s conservation status, banking seeds, and creating infrastructure for scientific research. She also highlighted the shrinking plant conservation capacity, plant blindness, and a lack of funding that compromises our ability to effectively conserve the country’s botanical resources.
Shifting from a U.S. flora focus to that of a single plant family, the next speaker, Dennis Whigham, Senior Botanist at the Smithsonian Environmental Research Center, spoke about the “North American Orchid Conservation Center – A Continental Scale Public-Private Effort to Establish a Model to Assure the Survival of Native Orchids.” North American terrestrial orchids pose a problem for conservation, Whigham explained, due to their complex life cycle involving fungi and animals, and their high sensitivity to environmental change. He provided a few examples from Australia of successful terrestrial orchid conservation programs, such as studies on Caladenia huegelii and Drakaea glyptodon. Yet in North America, very little is known on how to successfully conserve terrestrial native orchids.
The challenge is that mycorrhizal fungal partners are important at all life history stages of terrestrial orchids. A successful conservation program for these orchid species will require an understanding of the plant-fungi interaction; however, many fungi species that are necessary for orchid germination and dormancy have never been identified. Whigham argues for a continental-scale conservation effort that focuses on all aspects of orchid ecology to assure the survival of native terrestrial orchids. Using the small-whorled pogonia, Isotria medeoloides, as an example, Whigham explained the difficulty in understanding how to germinate the plant, and the threat of climate change leading to a changing distribution.
Then he presented the goals of the North American Orchid Conservation Center (NAOCC), a coalition of organizations dedicated to ensuring the survival of orchids native to the U.S. and Canada. The group’s aim is to overcome many of the challenges to conserving terrestrial orchids: protecting natural orchid populations; restoring populations; developing and maintaining national collections of seeds and mychorrhizal fungi; and cultivating native orchids in botanic gardens and arboretums for restoration and education purposes. NAOCC serves as a model for a national and integrated approach to conserving biodiversity. If successful, NAOCC will be the first attempt to assure the survival of an entire family of plants at a continental scale.
The next speaker, Stuart Pimm, the Doris Duke Chair of Conservation Ecology at the Nicholas School of the Environment at Duke University, spoke about threatened species in fragmented environments. His talk was entitled, “Most Threatened Plants are in Fragmented Habitats, So What Can We do to Reconnect Them?” He began his talk by discussing the big unanswered questions such as “how many plant species are there, where are they located, and what can we do to protect them?” Pimm explained that “missing” undescribed species tend to be rare. Are they in harm’s way? Where are they—in the tropics, moist tropics, or hotspots? He explained that in Brazil the greatest numbers of still missing species are not in the Amazon rain forest, but in the heavily impacted coastal Atlantic forest.
If most undescribed species are rare and in places where destruction of tropical biomes are high, then what is the best method to prevent their extinction? Pimm argues for large landscape-scale actions. He showed how the Brazilian coastal forest is riddled with small isolated patches, which typically support fewer species than the larger forests. He then went into a case study about his non-profit organization called SavingSpecies. They purchased land in southeastern Brazil, removed the cattle from the land, and restored the habitat by planting native trees. The cattle pastures that separated the fragments have been restored to reconnect the patches. He concluded by discussing the evidence he found of ecological healing – golden lion tamarins and pumas have been seen moving between previously isolated fragments. The solution to reconnecting these fragments, Pimm urged, is by raising money to pay for reforestation.
The last lecture of the Symposium was delivered by Chris Thomas from the University of York, who spoke about “The End of Trying to Re-create the Past.” Thomas began by saying that habitat changes are globally universal—from Europe, where all habitats have been modified, to the New World Tropics, which experienced pre-Columbian shifting cultivation. The traditional logic of conservation biology, explained Thomas, is to protect habitats, manage them traditionally, and recreate by restoring the habitats by referring to past biodiversity. The presence of climate change, however, may force a new strategy. Thomas provided data on the northern movement of British southern species, which have an average northward shift of their range margin of about 20 centimeters per hour (or about 5 meters per day). He showed an example of how the Greenland collared lemming has no overlap between its current distribution and the projected future distribution.
Climate change also complicates management decisions about invasive species. Thomas asked, “when is a species an invader?” He explained that Rhododendron ponticum, a species from the Iberian Peninsula, is considered an invasive species in the British Isles. Yet, the fossil record shows that the species occurred in the British Isles 200,000 years ago. If the Iberian subspecies is driven extinct within its current native distribution by climate change, should conservation biologists accept Britain as its future distribution? Thomas states that conservation biologists should change their philosophy from a situation where they want to stop the clock to a new paradigm where they should manage and adapt to the change. He concluded his talk by saying, “defining all change as negative dooms conservation to persistent failure.”
After the formal lectures, participants enjoyed a reception and dinner. The reception included a private tour of the exhibit “Orchids of Latin America,” featuring orchids from the Smithsonian Gardens Orchid Collection. This exhibit highlighted the importance of orchids in Latin American folklore and cultural traditions, explored how that region is a hotbed for scientific research on orchid biology and evolution, and examined conservation efforts to preserve them and their habitats for future generations. The reception was followed by dinner in the museum’s rotunda.
Next year, the Smithsonian Botanical Symposium will explore the topic of biogeography, the study of species across geographic space and through geological time, with an emphasis on patterns, islands, evolution, phylogenetics, endemism, and climate change. The date is set for Thursday, April 24 and Friday, April 25, 2014. Differing from years past, the 2014 symposium will be free to attend, but registration will be required. All are invited to attend.