“Plant Conservation Trends in North America North of Mexico”
The conservation of native plants, especially those experiencing threats and population declines, is dependent on accurate information about each species’ location, population health, and protection needs. In cooperation with State Natural Heritage Programs and Canadian Conservation Data Centres, the NatureServe Network has used a standardized and vetted methodology to assess each plant species’ risk of imperilment at subnational, national, and global scales for decades. These assessments, or ranks, determine priorities that support the protection and management of the most vulnerable plants. The NatureServe Network tracks the status of rare species through the mapping of Element Occurrences, which represent populations contributing to the survival and persistence of species.
This presentation will review trends in plant conservation in the US and Canada from NatureServe Network data, including conservation status assessments and Element Occurrences. We will highlight initiatives at state, regional, national, and global levels using status assessments to prioritize plant conservation. The presentation will discuss threats to plants—emerging, long-standing, and sometimes confounding—and efforts to address them. Finally, we will identify data and regulatory gaps in conservation and how these gaps may be filled by collaborations and newly available data such as online floras, digitized herbarium specimens, and citizen science data.
“Climate Change on Tropical Mountains: Vulnerability to Drought and Ecological Strategies of Canopy Epiphyte Communities”
Epiphytes are ubiquitous in tropical montane cloud forests (TMCF) and are important for ecosystem function. These canopy plants intercept atmospheric water and nutrients and contribute significant inputs of these resources to the forest floor. In addition, epiphytes provide food and habitat for dozens of animal species in the TMCF. Despite the importance of the epiphyte community for TMCF function, we know little about the variation in form and function within this species-rich community or about the ability of different species to tolerate climate change. In Monteverde, Costa Rica, changes in climate over the last 40 years include increases in air temperature, cloud-base heights and drought. These changes may be particularly problematic for canopy epiphytes, which are dissociated from resources on the ground. Our research indicates that cloud immersion induces foliar water uptake and that this process is important for epiphyte water balance. In addition, we have documented significant variation in leaf form and function of epiphytes; this variation exists along a continuum relating to foliar water uptake capacity vs. leaf water storage. We have also found that epiphytic shrubs, an abundant component of the epiphyte community in the TMCF, may be particularly vulnerable to increases in drought and cloud-base heights.
“Habitat Restoration: How to Make the Best Decisions About What Seed Provenances to Collect and Where to Use Them”
The US tallgrass prairie is one of the world’s most endangered ecosystems. It is also an ecosystem where ecological restoration has been practiced for nearly a century. Proper sourcing of seed for this restoration has never been straightforward, and it is becoming even more challenging and complex as the climate changes. For decades, restoration practitioners have subscribed to the “local is best” tenet, even if the definition of “local” was often widely divergent between projects. However, given rapid climate change, we can no longer assume that locally-sourced seeds are always the best option. Using examples from our work in the tallgrass prairie and the grasslands of the Colorado Plateau, we discuss what we are learning from provenance trials and how this may influence seed sourcing decisions. We review provisional seed zone maps and seed decision tools, including a new tool under development to assess options of plant provenance based on the goals and context of a given project.
Every year plant devotees make fascinating (and occasionally alarming) botanical discoveries in the hills and valleys, forests and grasslands, wetlands and barrens, lakes and rivers, mountaintops and beaches, and even urban environments across the Keystone State. It’s a Pennsylvania Botany Symposium tradition to invite all to submit photos and descriptions of “Cool Finds” made within the past decade or so anywhere in the Commonwealth. This presentation will review the latest reports and describe each within the ecological, bio-geographical, historical, geological, or cultural context that makes it noteworthy.
“The Story of the Hidden Heuchera: How Working Together as Botanists Leads to Better Outcomes than Working Apart”
The genus Heuchera is recognized as one of the most diverse endemic radiations of Saxifragaceae in North America, yet species delimitation and geographic distribution within the group remain controversial. Many species can be difficult to identify, including Heuchera alba, a narrow Appalachian endemic and globally imperiled (G2) taxon recorded only from West Virginia and Virginia that occurs in sympatry with H. pubescens and H. americana. A recent survey of the cliffside flora of the Shikellamy Bluffs, PA recorded dozens of Heuchera individuals that, through the use of social media, were positively identified as H. alba. Aided by examination of historical herbarium records, subsequent searches of similar habitats in Pennsylvania led to the discovery of seven more populations and established a significant range expansion for this rare species. The uncovering of H. alba in Pennsylvania is an exciting conservation outcome and an example of what can happen when botanists embrace a combination of modern and classical approaches to discovery and collaboration.
“The Extraordinary Biology of Some Pennsylvanian Ferns”
Pennsylvania harbors many species of ferns that exhibit an extraordinary biology. For instance, the bracken fern (Pteridium aquilinum) poisons organisms that eat it, including people, in diabolical ways. The mosquito fern (Azolla) floats on water and, although the world’s smallest fern, has the largest economic importance of any fern because it is used as a nitrogen-rich fertilizer in many tropical regions of the world. When dry, the leaves of the resurrection fern (Pleopeltis polypodioides) curl into rough C- and J-shapes and appear dead. After a soaking rain, the leaves resurrect within hours, expanding their blades and resuming photosynthesis. The rapid rehydration is made possible by water-absorbing scales on the undersides of the leaves. Highly unusual are Pennsylvanian ferns that lack a spore-bearing phase, never producing a “normal” plant with roots, stems, and leaves. Instead, they exist only in the minute gamete-producing phase (gametophytes) and reproduce asexually by means of several-celled gemmae. Even more strange is that they belong to primarily tropical genera. These and other unusual Pennsylvanian ferns will be highlighted in the talk.
“Digital Tools for Botanical Teaching and Research at Powdermill Nature Reserve?”
Powdermill Nature Reserve has developed several lines of digital access to botanical information as a way to connect with a broader community than those who visit the reserve in person. These include Web-based tools to provide information of interest to hobbyists and professionals alike, including emerging technologies such as Unmanned Aerial Vehicles (drones) and Virtual Reality 3D botanical models. This presentation will demonstrate several different kinds of products: a tool that plots the 20 most common trees surveyed across the reserve; an animated timeline that shows when 150 native plants bloom and provides gardening information; a 3D model of a forest research plot that can be navigated on the Web; a collection of 3D botanical models available for Virtual Reality experiences.
“Subfossil Leaves Reveal Streamside Tree Communities of the Pre-European Piedmont Landscape, Southeastern Pennsylvania”
Widespread deforestation, soil erosion, and milldam construction by European settlers greatly influenced stream morphology and riparian vegetation in the northeastern USA. The former broad wetlands were converted into incised streams with high, unstable banks that support mostly weedy vegetation. Vast accumulations of fine-grained ‘‘legacy’’ sediments that blanketed the regional landscape are now being reworked from stream banks, impairing the ecological health of downstream water bodies. Because potential restoration is impaired by lack of direct knowledge of pre-settlement vegetation, we studied subfossil leaf floras recovered from precolonial hydric soils under legacy sediments at two obsolete milldam sites in southeastern Pennsylvania. At Denlingers Mill in Lancaster County, we interpret the circa early-1700s subfossil assemblage to represent an upland Red Oak-American Beech mixed hardwood forest. The White Clay Creek assemblage (circa 1650) from Chester County is composed of woody species with both riparian and hill-slope affinities. Our results add significantly to understanding of the pre-European settlement landscape, especially of the hardwood tree flora. Generally overlooked subfossil leaves can provide well-constrained paleoecological data with much potential value for restoration decisions.
Coauthors: Sara Elliott, Christen Grettenberger, Michael Donovan (Alumni, Penn State Paleobotany Lab); Robert Walter, Dorothy Merritts (Franklin & Marshall College).