Current Fellows

Betsabe Castro-Escobar

University of California, Berkeley (Calif.)

On the Trail of the Calabash Trees: Understanding the Evolution, Geography, Domestication and Uses of Crescentia Species in Caribbean Islands

Plants provide us with raw materials to sustain human life. Over time, depending on how plants are used, they could be selected for particular traits that are both desirable to people and favorable for the plants success and evolution, thus promoting variation within a group of plants. The plants explored for my study are the calabash trees, also known as higüeros or güiras. Of the six species, three are from the continental Americas and three are of island origin. Of these species, five are present across the Caribbean. The plants are moderate-size trees that produce round fruits that greatly vary in shape and size, with a thin hard shell and soft white pulp. Crescentia cujete (the most widely spread) seems to be the most commonly used of all calabash trees. By conducting a multi-sited study among Caribbean islands in the Major Antilles, I aim to understand: how local people select, prepare, and consume these calabash plants; why they choose these plants and not others; how these practices might be shared or be different across the Caribbean landscape; where did these plants originate and how have they spread across the Caribbean. By studying the variation of the calabash trees in the Caribbean Basin, my interest is to understand how people have promote the evolution and conservation of these medicinal, material, and culturally significant plants.

Reasearch Advisors: Dr. Paul V. A. Fine, Department of Integrative Biology, University of California, Berkeley and Dr. Thomas J. Carlson, Department of Integrative Biology, University of California, Berkeley

Current Fellows

Toby Liss

State University of New York College of Environmental Science and Forestry (New York)

The Role of Plant Assemblage Diversity in Evapotranspiration: A Novel Application to Enhance Green Roof Function

Each year as cities grow, the areas covered by hard materials like rooftops, asphalt, and concrete grow too. These surfaces, although great for walking, driving, biking, and staying dry, are impervious – that is, they don’t allow water to soak in. Many cities have storm drains that take the stormwater from urban hard surfaces to the local rivers and lakes. Unfortunately, stormwater sometimes carries oil, gas, and other contaminants with it from the city to the local waters. When there is a large storm, the stormwater can mix with sewage and end up in your local lake or river. Green roofs are one way to help this problem. By putting soil and plants on a roof, we can slow down the rainwater or even stop it from running off at all. The plants send the water back into the atmosphere in a process called transpiration. But living on a green roof is really tough for plants! So we need to pick species that are adapted to the dry, windy, hot conditions on roofs. But what combination of plants will remove the most water? My project goal is to learn more about how plants work together as a group to remove water from the soil, and use this to help designers make the best choices of plants when they build a green roof. Improving green roofs can mean safer, cleaner water to swim, fish, and play in for city dwellers and rural residents too!

Research Advisor: Dr. Donald J. Leopold, Department of Environmental and Forest Biology, State University of New York College of Environmental Science and Forestry

Current Fellows

Sarick Matzen

University of California, Berkeley (Calif.)

Plant-based Brownfield Remediation: Using Advanced Imaging Techniques to Determine Arsenic Uptake Mechanisms in the Hyperaccumulating Fern , Pteris vittata L.

Arsenic is not only an historic poison, but a current contaminant in city soils where urban farmers want to grow food. In keeping with sustainability ethics, urban farmers want affordable, low-waste ways to clean up soil, in contrast to expensive conventional methods where the contaminated soil is dug up and dumped elsewhere. Plants could offer a key to sustainable soil cleanup. A brake fern, Pteris vittata, pulls arsenic out of the soil and stores the toxin in its fronds. In a process called phytoextraction, we can then harvest the fronds and remove arsenic while leaving the valuable topsoil in place. However, removing arsenic with the brake fern is slow, with cleanup time estimates of several decades. To increase arsenic uptake in the fern, we must start with the soil, determining how the fern accesses the relatively insoluble arsenic. Arsenic binds strongly to iron oxide (rust) soil minerals, and must leave these mineral particles in order to enter the fern roots. How this happens is not clear, but the fern could free arsenic from soil minerals as it releases chemicals to scavenge necessary nutrients, like iron and phosphorus. With Botany in Action support, I will use innovative imaging methods, including very bright X-rays and special gels, to map this root zone chemistry and learn more about what happens when the arsenic makes the journey from the soil grains to the root interior. We can then use this information to speed up phytoextraction and clean up arsenic-contaminated soils for urban agriculture.

Research Advisor: Dr. Celine Pallud, Department of Plant and Microbial Biology, University of California, Berkeley

Current Fellows

Nichole Tiernan

Florida International University (Florida)

Systematics and Conservation of Endemic Caribbean Island Plumeria (Apocynaceae)

The Neotropical genus Plumeria L. (Apocynaceae), commonly known as Frangipani, is an ornamental garden plant that occurs throughout the Caribbean islands. Though several species are common in tropical gardens, many wild growing species are not present anywhere in horticulture. Resolving the confusing taxonomy of the Caribbean species of Plumeria L. will unveil wild varieties currently not in cultivation. Classification studies of threatened plants provide a framework for what and where to conserve. The Caribbean Islands are a hotspot of biodiversity and a prime focus for conservation efforts. The revised classification generated by this study will help inform conservation threats of a charismatic genus providing substantial conservation and economic significance in the Caribbean. Florida International University undergraduate interns will continue collecting data as part of an ongoing pollination study, shedding light into the breeding and pollination systems of this important ornamental genus. High school interns will work on this project as part of the highly competitive Fairchild Challenge Internship; both of these projects will provide STEM education to students pursuing careers in plant sciences.

Research Advisor: Dr. Javier Francisco-Ortega, Department of Biological Science, Florida International University

Current Fellows

Kate Douthat

Rutgers, The State University of New Jersey (New Jersey)

The Plant Communities of Stormwater Detention Basins in New Jersey: Types, Landscapes and Local Drivers

When it rains, stormwater runs across roads, parking lots, and lawns, picking up pollutants and debris. In order to prevent flooding in areas where the soil is not absorbent because it is compacted or covered by pavement or buildings, this stormwater runoff is temporarily stored in detention basins until it drains to streams. Some detention basins are lined with native plants instead of mown grass, which reduces mowing and saves time and money. When detention basins are lined with native plants, the thicker vegetation can trap contaminants and prevent them from running into streams and drinking water. This type of detention basin can also provide islands of refuge for songbirds and pollinators in urban landscapes. The plants in these environments must survive difficult conditions, and the species that are planted when basins are built often give way to other species after a few years. Which plants thrive in stormwater basins, and the exact role they play in removing pollutants or providing habitat, is not yet well understood. This project will document the groups of plant in stormwater basins in New Jersey and compare them to soil types and landscape factors, such as proximity to roads or residential areas. By understanding the plant communities that are living in in stormwater basins and how they are shaped by factors in the environment, we can improve basin design, improving water quality and the beauty of the landscape.

Research Advisor: Dr. Jean Marie Hartman

Current Fellows

Lynnaun Johnson

The Chicago Botanic Garden and Northwestern University (Illinois)

Investigating the Phorophyte Specificity of Dendrophylax lindenii, the Ghost Orchid: Are Mycorrhizal Fungi Drivers of Rarity? 

The Ghost Orchid, Dendrophylax lindenii, is one of the rarest and most famous orchids in North America. The native distribution of the Ghost Orchid is restricted to the western tip of Cuba and southern Florida. Like most North American orchids, the Ghost Orchid is threatened with extinction from urbanization, pollution and climate change. To assist efforts to conserve the Ghost Orchid, it is important to understand the interactions the Ghost Orchid has with other organisms in its native habitat. Two important relationships the Ghost Orchid has is with the trees it grows on and with fungi that support its growth. Fungi are important to Ghost Orchids because Ghost Orchids are leafless and require symbiotic fungi to supply nutrients for their growth. If the source of the fungi is the bark of its host tree, this link can explain why the Ghost Orchid prefers to grow on certain tree species. My research is investigating if the distribution of the essential symbiotic fungi drives the fine scale distribution of the orchid.  To date my study has been restricted to the Florida population, but information from the Cuban population is needed to test these ideas. This study will be conducted on the only known Cuban population of Ghost Orchids which is restricted to Guanahacabibes National Park at the western tip of the island. The results will add to our understanding of the biology of epiphytic, leafless orchids and will generate recommendations for conservation of Ghost Orchids and other epiphytic orchids.

Research Advisor: Dr. Gregory M. Mueller, Chicago Botanic Garden

Top photo © Paul g. Wiegman