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Being the most abundant family of flowering plants implies being able to adapt to the largest range of habitats.
Figure 1: Mexipedium xerophyticum from Mexico (left), Phragmipedium Kovachii from Peru (middle), Paphiopedilum micranthum from China (right).
Even Though we may consider habitats as un-changing spaces (until climate change) where nature exists, habitats have evolved much like the organisms that inhabit them. Throughout millions of years of slow constant change, tectonic plate movement, atmospheric composition, and temperature changes have defined the life that can exist on the planet. Habitat change has been the main source of extinction in the history of living organisms. Ice ages, carbonation events, and extreme temperature shifts have exceeded evolutionary pressure for organisms to adapt to the new climatic and environmental conditions. Orchids have been able to avoid mass extinction by adapting to a wide range of habitats, some modern and some millions of years old. Epiphytism or the adaptation to live on trees and other vegetation means that orchids do not need to compete with trees and fast-growing terrestrial plants for forest floor and often scarce rainfall. Instead, most orchids have adapted to living on the forest roof among the high-growing trunks of trees where their aerial roots can capture the air humidity. Wherever trees go, orchids can follow (given sufficient temperature and humidity). On the other side of the spectrum, orchids have also evolved lithophytic, or the adaptation to live on top of rocks. Of Course, living in these nutrient-poor habitats away from the fertile soil below also implies that orchids must thrive with minimal nutrition from the air and rainwater. For epiphytes, detritus or the falling dead matter from the top of trees such as leaves can provide slow diffusing nutrition. But for lithophytes, they must use the limited minerals from the rocks they grow on. For instance, species growing on limestone must use the calcium carbonate, magnesium, and other minerals that will slowly be dissolved and carried to the roots by the seepage and flow of water from above.
Figure 2: Parvisepalum Subgenus from Paphiopedilum limestone growing lithophytic orchids
For this project, my goal is to replicate the seeping limestone cliff habitats of Mexico, Southeast Asia, Ecuador and Peru. This is where the parvisepalum subgenus of Asian Paphiopedilum, some South American Phragmipediums and the legendary Mexipedium xeophyticum. All of these plants are relatively rare in nature due to climate change, poaching, wildfires and habitat extinction. Limestone is a relatively soluble mineral rock and is eroded readily. This indicates that over the years, these habitats have been slowly disappearing and the orchids that live on them, or at least in the ways we know them, will be no more. Southeast Asia and South America still have large ecosystems with seeping limestone cliffs. However, Mexico has a limited range of these formations which has reduced the range of these types of Orchids.
Figure 3: Habitat of Mexipedium, one the last of two known clonal populations.
There is much debate on whether Mexipedium Xerophyticum is functionally extinct meaning that there isn't enough genetic diversity or probability for natural reproduction. The two populations that still remain are suspected to be clonal populations. Unexpectedly, this species is far from extinction as orchid collectors and growers were able to reproduce two plants that were taken from the initial discovery back in 1991. Every couple of years, a grower is able to produce seeds and seedlings from the offspring of the original populations but the lack of genetic diversity makes this process harder each time it happens. Hybrids of this species are not unheard of but they need to be between genera, a more complicated process than intra-genera (say Phragmipedium a X Phragmipedium b instead of Phragmipedium d X Paphiopedilum e).
Figure 4, 5 (A,B): range of phragmipedium and Parvisepalum respectively
Figure 6: Potential distribution of Mexipedium (the real one is only 1 hectare and is kept a secret)
How can technology allow us to study and replicate the habitat and ecology?
Figure 7: Structure of the Phragmipedium with an inclined base to allow water to flow, extender viewing window and water circulation system.
Reproducing the climate conditions of these habitats is a great challenge due to their uniqueness and seasonality. High humidity may only be present at certain times of the day and night and only in certain seasons. Heavy rainfall often determines the amount of time the seepage will flow as mountains are able to delay the full release of rainfall for some time. Weather stations are a great way to monitor the changes both seasonal and annual that happen in the habitat of these orchids. We can spot anomalies and we can get better insight into how to replicate these conditions for ex-situ growing. For this project, I will use an Arduino Uno Wifi that will get real-time or as close to meteorological data, and then using an array of electronic devices the conditions will be replicated in the greenhouse. If everything goes correctly, I will be also able to process and study the data, perhaps over the years, I may be able to produce a quantitative analysis of how climate change has affected this particular habitat and show how those shifts impact or would impact the ecosystems that live in them. All of this may be possible by studying the response of orchids to the changing conditions through growth, appearance, and willingness to flower.
At the moment of writing, I am planning the design of the orchidarium as well as the circuit and the code. Most of the electronic components and tools used to build this have been kindly sponsored by the RS team to whom I’m grateful.
Most images are courtesy of http://slipperorchids.info/
García, E. A. P. (2009). El redescubrimiento de Mexipedium xerophyticum (Soto Arenas, Salazar & Hágsater) VA Albert & MW Chase. Lankesteriana: International Journal on Orchidology.