The mystery of an unusual Panamanian plant’s dispersal

Zamia pseudoparasitica is the only species in its genus that grows on other trees, but little is known about how it persists in the canopy. Credit: Pedro Luis Castillo, Smithsonian Tropical Research Institute

Sleeping in a car may be a necessity for scientists conducting fieldwork. In 2020, a team of young researchers spent two nights sleeping in their car in the mountains of western Panama. The second time it was not intentional: their car broke down in El Copé, in Coclé province, and they had to wait for a tow truck. At least a woman from the area took pity on them and offered them fried plantains and coffee. A few years and a pandemic later, the study resulting from those adventures was published in the journal Ecology and Evolution, revealing clues about the natural history of an unusual plant that only exists in Panama.

Zamia pseudoparasitica is a unique species that is only found in the montane cloud forests of western Panama. It is a cycad, belonging to a very ancient order of plants that resemble and produce cones. The genus, Zamia, originated 68.3 million years ago, when there were still dinosaurs roaming the planet. But the most unusual thing about this particular species is that it is the only epiphytic Zamia in the world: it does not grow on the ground, but hangs on to the branches and trunks of trees using its roots, generally 7-20 meters above the ground.

To begin to solve the mystery of how it persists in the canopy, a somewhat fortuitous research team formed. Doctoral student at the Max Planck Institute for Animal Behavior and visiting scientist at the Smithsonian Tropical Research Institute (STRI), Claudio Monteza, and Senacyt-STRI intern and biologist Lilisbeth Rodríguez, ran into each other one day at the Smithsonian research station on Barro Colorado Island, in the Panama Canal. She told him about the project that she was conducting with Z. pseudoparasitica under the supervision of Juan Carlos Villarreal, a biologist from Laval University in Canada, and Kristin Saltonstall, a STRI staff scientist in Panama.

“My goal was to collect samples from different species of Zamias in the country,” Rodríguez said. “These samples would later be analyzed in the laboratory to find out what species of fungi and bacteria grow inside their leaves.”

Given her experience climbing trees, Lilisbeth Rodríguez borrowed some camera traps from Claudio Monteza to place them high up in the trees and document which animals interacted with Zamia pseudoparasitica. Credit: Claudio Monteza, Smithsonian Tropical Research Institute and Max Planck Institute for Animal Behavior.

Her supervisor, Juan Carlos Villarreal, told her that no one knew how this plant’s seeds were dispersed: it was still a mystery. But given her experience climbing trees as part of the project, and aware of Claudio’s work with to study mammal behavior, Lilisbeth asked to borrow some traps. She wanted to place them high up in the trees to find out what species of animals interacted with the Zamia.

Claudio joined the project, as did Pedro Luis Castillo, a research assistant at STRI, and Edgar Toribio, a tour guide from Santa Fe. At the end of 2019, they placed the camera traps on trees in three protected areas where Z. pseudoparasitica grows: the Palo Seco Protected Forest, the Santa Fe National Park and the Omar Torrijos Herrera National Park in El Copé. In March, shortly before a mandatory quarantine due to the pandemic began, they collected the camera traps.

What they saw in the images could help explain how Z. pseudoparasitica disperses in the trees and not on the ground like other Zamia species. While seven different mammals visited the branches where Z. pseudoparasitica were growing, some paid no attention to the plant; others, such as capuchin monkeys, opossums and kinkajous inspected its cones, some even licked them, but did not take the seeds. Only the northern olingo (Bassaricyon gabbii), a nocturnal tree-dwelling mammal that is active high in the canopy and feeds primarily on fruit, was repeatedly observed at all three sites. When the cones of Z. pseudoparasitica were still closed and immature, they were seen inspecting and biting them. Once opened, the cameras detected the olingos collecting up to four seeds at a time.

“It could be that the olingos are taking the seeds to what would be their den or perhaps to a seed bank,” Monteza explained. “If they are, which we don’t yet know for sure, it would help to explain why this is the only Zamia species that lives in the .”

The northern olingo (Bassaricyon gabbii), a nocturnal tree-dwelling mammal, was observed repeatedly inspecting and biting at the immature cones of Z. pseudoparasitica and then taking up to four seeds at a time once open. Credit: Claudio Monteza, Smithsonian Tropical Research Institute and Max Planck Institute for Animal Behavior.

In other words, if the seeds are being stored in the canopy by olingos, chances are they might end up in favorable places for germination up there.

“The montane forests of western Panama are very unique, filled with many species that aren’t found anywhere else,” said Kristin Saltonstall, co-supervisor of the project. “It’s exciting to document this interaction between such a special plant and an animal that is also poorly understood.”

Z. pseudoparasitica is a true epiphyte; that is to say, it spends its entire life in the forest canopy,” said Monteza. “How it persists there is a mystery that perhaps we will begin to solve with these initial findings. It’s exciting because we can continue to the next phase by collecting more data; for example, it occurs to us that we can mark the seeds with bioluminescence, wait for the olingos to take them away and then search for the seeds at night.”

More information:
Claudio M. Monteza‐Moreno et al, Arboreal camera trapping sheds light on seed dispersal of the world’s only epiphytic gymnosperm: Zamia pseudoparasitica, Ecology and Evolution (2022). DOI: 10.1002/ece3.8769

The mystery of an unusual Panamanian plant’s dispersal (2022, March 25)
retrieved 26 March 2022

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Hexbyte Glen Cove Mystery of glacial lake floods solved

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The hot water drill used to drill through the glacier to the subglacial lakes. The drill stem is hundreds of meters below in the ice, suspended on a rubber hose through which hot water is pumped down. Credit: Eric Gaidos

A long-standing mystery in the study of glaciers was recently —- and serendipitously—solved by a team led by University of Hawai’i at Mānoa astrobiologist and earth scientist Eric Gaidos. Their findings were published this week in the journal Geophysical Research Letters.

The mystery involves floods or “jokulhlaups” that emerge suddenly and unpredictably from or like those in Iceland where volcanic heat melts the ice and accumulates in lakes underneath the glaciers. Scientists have long studied the development of these floods, which are some of the largest on Earth.

“These floods may affect the motion of some glaciers and are a significant hazard in Iceland,” said Gaidos, professor at the UH Mānoa School of Ocean and Earth Science and Technology (SOEST). “But the mechanism and timing of the initiation of these floods has not been understood.”

Then, in June 2015, an unexpected series of events revealed how these floods start.

That summer, Gaidos and colleagues drilled a hole to one of the Icelandic lakes to study its microbial life. While collecting samples through the borehole, the team noticed a downwards current, like a bathtub drain, in the hole.

“The flow was so strong we nearly lost our sensors and sampling equipment into the hole,” said Gaidos. “We surmised that we had accidentally connected a inside the glacier to the beneath. That water mass was rapidly draining into the lake.”

Illustration of the water movement that may have triggered the flood of June 2015 (arrows indicate flow direction): the subglacial lake, warmed to 4 C by geothermal input, the perched reservoir fed by summer melt through the firn layer, a water-filled system of crevasses and conduits (moulins), our borehole, and the outlet under the ice dam. Credit: Gaidos, et al. (2020)

A few days later, after the team had left the glacier, the lake drained in a . Fortunately, the flood was small and Icelanders have an elaborate early-warning system on their rivers so no people were hurt, nor infrastructure damaged in this event, Gaidos assured.

The researchers used a computer model of the draining of the flow through the hole , and its effect on the lake, to show that this could have triggered the flood.

“We discovered that the glacier can contain smaller bodies of water above the lakes fed by summer melting,” said Gaidos. “If this water body is hydraulically connected to the lake then the pressure in the lake rises and that allows water to start draining out underneath the glacier.”

In June 2015, a team led by Gaidos used hot water to melt a hole through 250 meters of ice to sample a lake beneath a glacier in Iceland. Credit: Eric Gaidos

While the team made an artificial connection to the lake in 2015, natural connections can form when water from rain or melting snow accumulates in crevasses and the pressure eventually forces a crack through the glacier to the lake. This discovery provides a new understanding of how these floods can start and how this depends on weather and the season.

Collaborators in Iceland are continuing to research this phenomenon using radio echo-sounding to search for water bodies within the ice, as well as study the larger lake below it.

More information:
E. Gaidos et al, Après Nous, le Déluge: A Human‐Triggered Jökulhlaup from a Subglacial Lake, Geophysical Research Letters (2020). DOI: 10.1029/2020GL089876

Mystery of glacial lake floods solved (2020, November 7)
retrieved 8 November 2020

This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no
part may be reproduced without the written permission. The content is provided for information purposes only.