The Plant Press

From The Plant Press, Vol. 26, No. 3, July 2023.

Abstracts from the speakers of the 20^th Smithsonian Botanical Symposium

The 20^th Smithsonian Botanical Symposium, “New Horizons in the Study of Neotropical Floras,” was held on 19 May 2023. The invited speakers specialize in natural history, geographic diversity, evolution, and conservation of plants in the Neotropics. Below are the abstracts from the papers that were presented by the invited speakers.

W. John Kress
National Museum of Natural History, USA
“The complexity of nature: A coevolutionary mosaic of plants and animals in the Neotropics”

The complexity of life on Earth is a product of the diversity of species multiplied by the diversity of their interactions. The quantification of species diversity, which requires both correct identification and resolved evolutionary patterns, is a prerequisite to accurately interpret their interactions. I will focus on one charismatic group of neotropical plants in the genus Heliconia and the ecology of the hummingbird pollinators with which they have coevolved. These ecological interactions between the plants and pollinators reveal their intricate patterns of evolutionary history and also how these species may respond to today’s rapidly changing planet.

M. Alejandra Jaramillo
Universidad Militar Nueva Granada, Colombia
“Piper evolution and ecology: A peppery tale from the understory”

The genus Piper is one of the largest lineages of flowering plants. It is also a dominant element of the forest understory in the Neotropics (but also common and diverse in Asian tropics). Piper is also diverse locally. In a forest reserve like La Selva, you can find 40 different species. In a small circle plot of 10 m diameter, you can encounter 25 plants and up to 7 species! Molecular phylogenetics has been instrumental in consolidating an infraspecific classification and as a frame to ask ecological questions with an evolutionary framework. Chemistry and the interconnection with herbivores are key for Piper species co-existence. As part of the spectrum, we cannot discard the role of plant growth forms and co-existing microorganisms. Species diversity is highest at mid-elevation (ca. 1,000 m in elev.), and the Andes foothills seem crucial for the genus's extensive diversification. We try to avoid overwhelming ourselves with the large numbers of species in the genus. Still, new taxa pop up in the forest or the herbarium cabinet every time we dare to look closely. We are using the immense diversity of this genus to ask all types of questions about the tropical forest understory. I will tell you a few peppery stories to tickle your curiosity.

Gregory W. Stull
National Museum of Natural History, USA
“Plant migrations and the assembly of the Neotropical flora: insights from the Mesoamerican-eastern North American biogeographic disjunction pattern”

The assembly of the present-day Neotropical flora has been greatly influenced by plant migrations into the region from different parts of the globe throughout the Cenozoic (66 to 0 mya). The highlands of Mesoamerica (including central and southern Mexico and Central America) harbor remarkable levels of plant diversity including an unusual mix of species with ‘tropical’ and ‘temperate’ ancestries. The latter includes numerous species showing a geographic disjunction between Mesoamerican (MAM) cloud forests and mesic temperate forests of eastern North America (ENA), separated by vast expanses of arid habitat across northern Mexico and the southwestern USA. These MAM-ENA disjuncts have been of interest for over 75 years, but there have been remarkably few recent studies attempting to document the number of species showing this disjunction pattern or the evolutionary and geologic history underlying its formation. In this talk, I will provide an overview of this poorly studied disjunction pattern. Recent work has revealed >100 examples of this disjunction pattern in seed plants alone, including both species with disjunct populations as well as sister species (or lineages) disjunct between these regions. The examples documented so far span the phylogenetic breadth of seed plants and represent the gamut of plant growth forms and life history strategies. Preliminary work also suggests that many cloud forest populations likely represent undescribed species, but the vast majority of these disjuncts have been entirely unstudied in the context of this biogeographic pattern. Overall, the MAM-ENA disjunction pattern represents an excellent system for studying how plant migrations between Mesoamerica and North America contributed to the historical assembly of diverse (and imperiled) forest ecosystems in these regions. More broadly, this disjunction pattern represents an incredibly rich system for studying the evolutionary and ecological responses of American temperate forests to climate change over short (Pleistocene) and longer (Cenozoic) time scales. I will conclude by outlining promising avenues for future research on this biogeographic pattern that involve bolstering relationships among US, Mexican, and Central American botanists with the goal of tackling urgent problems in biodiversity science and conservation across the Americas.

Alejandra Vasco
Botanical Research Institute of Texas, USA
“Accelerating lineage discovery to document Neotropical fern diversity”

The process of documenting and describing biodiversity often cannot keep up with the rate of habitat loss and the extinction of species. This is especially true in tropical regions of the world, where the number of undescribed and poorly known species is highest, and biodiversity is most severely threatened. This project aims to contribute to documentation of Earth’s plant diversity by studying the diversity of ferns in Colombia, one of the most species-rich countries on Earth. The proposed research is documenting Colombian fern diversity within a unified taxonomic and evolutionary context, primarily through four interrelated activities. First, we are addressing major gaps in our understanding of species distributions by conducting expeditions to understudied regions of Colombia and examining collections at major Colombian and US herbaria. Second, we are expanding resources for Pteridoportal, a Symbiota portal that serves as a publicly available, specimen-driven taxonomic resource for fern diversity research. Third, we are generating genomic resources for all species of ferns in Colombia, including a DNA and leaf-tissue bank for all collections, ploidy estimates, and target capture sequence data to conduct comprehensive phylogenomic analyses. Finally, we are integrating the data and resources generated through this work to detect and describe yet-overlooked diversity.

Paola Pedraza-Peñalosa
The New York Botanical Garden, USA
“Documenting the flora of a diversity hotspot: Las Orquideas National Park, Colombia”

Western Colombia is regarded as one of the most exciting frontiers for botanical exploration in the Neotropics because of its known levels of diversity and endemic species. In analyzing Neotropical diversity, the areas with the highest angiosperm biodiversity were specifically found in the Colombian Western Cordillera (Andes) and Chocó region. Unfortunately, floristic studies of these regions are insufficient and outdated. In general, multi-institutional explorations of the Colombian flora based on modern field and herbarium work have been rare for decades and Colombian species are conspicuously underrepresented in monographic and phylogenetic works. Las Orquídeas National Park, strategically located in western Colombia, comprises vegetation from both the Tropical Andes and adjacent Chocó. Its vascular plants were recently documented through the implementation of a holistic approach to field work that prioritized unexplored localities, encouraged specialized collecting, as well as balanced tree and non-tree sampling. As result, more than 2,000 species of vascular plants were identified, including numerous exciting new species. Also significant is the impact of the herbarium collections: those from the mega-diverse northern Andes and Chocó regions were doubled at NY, while the electronic vouchers of the park increased by more than 600% at the Colombian virtual herbarium (COL).

Acknowledgments

The success of the Symposium was due to the significant time and efforts of the following people:

Organizing Committee: Pedro Acevedo, Amy Bolton, Joy Columbus, Laurence Dorr, Rose Gulledge, Gary Krupnick, Susan Pell, Paul Peterson, Eric Schuettpelz, Kenneth Wurdack, and Elizabeth Zimmer

Administrative Support: MaryAnn Apicelli, David Jenkins, Tisha Lee, the José Cuatrecasas Botanical Fund, and the Mellon Foundation