Paphiopedilum ooii and Paphiopedilum xkimballianum

[Rick]

If the wild plants were adaptable enough to conform to a GH habitat in the first place then why isn't the converse true? Also since my GH conditions are different from everyone else then why are we still able to transfer plants around to each other without loosing everything? However, there is no competition in the GH environment, and orchids in general are fringe or transition species that are not competitively aggressive.

The loss of habitat issue really is key, and more subtle than most people believe.

In many cases when orchids are removed from the wild several other activities may also occur making that habitat inhospitable to key plants. For instance adding roads to an area will often change the hydrology of an area by blocking recharge zones. This in turn favors growth of invasive or competitive interactions among understory plants even though the tree canopy is intact. Even though the forest would seem intact, the habitat is not the same and is hostile to replaced orchids (kind of like organ rejection in humans). Really the orchid hasn't changed ex situ, but the forest has changed and is now a different hostile habitat altogether. This makes even in situ conservation very difficult.

You kind of need to ask how people are coming up with all these collected orchids in the first place? There's kind of a limit as to how far some one on foot with a sack on their back is willing to travel just to collect a plant for a pittance. The human communities are growing and spreading farther out into jungle habitats and making both subtle and gross changes as they develop. Generally when humans move into an area they bring changes with them that spread very far from the centers of both villages and cities. Paved roads are a small example. Habitat restoration is certainly doable (I have personal experience in this area), but it requires a lot of effort and attention.

 

[paphioboy]

Also since my GH conditions are different from everyone else then why are we still able to transfer plants around to each other without loosing everything?

I think that's because we try so hard to keep them alive In a natural habitat situation, I highly doubt any FCC/AOS quality paphs are able to grow to their full potential just chucked onto a bed of leaf litter..

 

[Rick]

I think that's because we try so hard to keep them alive In a natural habitat situation, I highly doubt any FCC/AOS quality paphs are able to grow to their full potential just chucked onto a bed of leaf litter..

Hard to say. Seems like we periodically get to see pics of in situ plants that are superior to FCC or CCE plants. Roth is always telling us about FCC quality plants that are either jungle collected or no more than 1st generation captive plants. Seems like we looked into this before, comparing the size of line bred FCC flowers to the taxonomic description (based on wild collected plants) and really didn't see all that much difference.

"Just chucked onto a bed of leaf litter" probably will not work if that bed of leaf litter is in a patch of disturbed forest surrounded by weeds. Near my house is a nursery that specializes in artificial propagation of native species. Many are uncommon forest species that have been line bred for a generation or two. We buy lots of their stuff, and stick it in our backyard. Most do very well if we pay attention to them during the first couple of years, watering and keeping weeds away from them (NO feeding). After 3 years they usually are pretty self sufficient.

Initially our property was a well tended mowed grass yard with scattered well established trees. About 14 years ago we designated some patches for "reforestation" and covered the grass (under the trees) with sheets of cardboard and added about 6 inches of leaves and mulch. We have been adding plants to this system every year since. Most of the time we never water and weeds never seem to come up. Wherever we punch new holes through the leaf litter to the underlying clay for new plants we do see weeds pop up (which we pull). We never rake the leaves away from these established "reforested" places, and after a few years, the area around new plantings fills in and becomes indistinguishable with the rest of the area. At that point plants are pretty self sufficient.

 

[emydura]

A glasshouse is a pretty artificial environment. It is a long way from their natural habitat. There are few selection processes in a glasshouse. We regulate the environmental conditions. We kill all potential predators. Only a very small number of the fittest, strongest seedlings survive in the natural habitat. In the glasshouse we can grow to flowering even the weakest, least vigorous seedlings.

As you say habitat destruction is the biggest issue. Without a habitat, ex situ conservation will be the only alternative. That may work in the short-term but I don’t think it can go on indefinitely. The longer you require ex situ conservation the less chance these species will eventually be recolonised.

What do you think would be the best method of recolonisation? Put large flowering size plants back into the natural environment or just release masses of seed and hope through genetic diversity some seedlings may adapt. Or maybe a combination of both?

David

 

[Rick]

A glasshouse is a pretty artificial environment. It is a long way from their natural habitat. There are few selection processes in a glasshouse. We regulate the environmental conditions. We kill all potential predators. Only a very small number of the fittest, strongest seedlings survive in the natural habitat. In the glasshouse we can grow to flowering even the weakest, least vigorous seedlings.

As you say habitat destruction is the biggest issue. Without a habitat, ex situ conservation will be the only alternative. That may work in the short-term but I don’t think it can go on indefinitely. The longer you require ex situ conservation the less chance these species will eventually be recolonised.

What do you think would be the best method of recolonisation? Put large flowering size plants back into the natural environment or just release masses of seed and hope through genetic diversity some seedlings may adapt. Or maybe a combination of both?

David

The most recent edition of Orchids highlights some efforts on orchid conservation. One article is about orchids in Western Australia.

Seed dispersal is probably not very effective, but imposible to track so hard to say. If the habitat is disturbed (even subtley), the mychorizal symbiots will not be present to germinate seed, and success will be Zero. Putting out adult plants is probably the most successful, and easiest to track, but takes the most time and money to accomplish on a large scale. Putting out established seedlings is probably the best intersection of plant stability and cost. If the plants are highly dependent on the mycorhrizae, then they could end up dead ending in the next generation (just like the seed). Some concern has been expressed on pollinators, but since most orchids are deceptive pollinators, the presence or absence of pollinators is generally not dependent on the presence of the orchid in the first place. However, if the pollinator is gone for whatever reason, then multigenerational success would probably be limited.

The projects I've read about for Western Australia terrestrials (a few for US and European terrestrials too) usually include culture and reintroduction of the mycorhrhizal symbiots with seedlings.

Concerning the GH factors though, just because we've "selected" for GH conditions doesn't mean the genes are lost in the culls. We've just got some of the plants to alternatively express some genes (that may not be present in all individuals). In order to get something that dependent on specific conditions you would have to select from ex-situ produced mutations.

I work in an environmental toxicology lab with clones of water fleas. These are parthenogenic organisms, and with a high generation rate, lab specific colonies of these guys will be 99% identical genetically in just a few months. But you can take critters from my lab or any other lab and get just about the same response to a wide suite of toxicants. Different labs try to come up with genetic strains resistent to all sorts of different compounds, and generally get no better than +/- 20% over standard responses. This has been going on since the 70's so probably a lot more generations have come and gone compared to the last 100 years of orchid culture. The mutation rate must be much lower than for say fruit flies that may be resistent to certain pesticides. Obviously bacteria have a high enough mutation rate to develop resistances to different antibiotics. But I don't think orchids have that high a generation rate (5 years??) to get enough mutations in a strain to make them genetically incapable of growing in a forest instead of GH.