Tuesday, 17 September 2013

From Ridge to Reef: Conservation and education opportunities in Belize! Presentation at 11:30 on Friday Sept. 20th in Redpath

As a former NEO student I am really excited to announce the possibility of a collaboration between the NEO program and a tropical field station my partner and I have built in the Maya Mountains of Belize.

Our field station, called the T.R.E.E.S Hosting Center, has been operating since March 2013. Our facilities are set on 200 acres of Lowland Broadleaf Forest at about 200 m elevation. Most of this forest is primary growth and as it is in the foothills of the mountains there is a lot of precipitation that creates a dense rainforest. We have over a km of river (Dry Creek) that runs through our site as well as numerous tributaries. Finally, some secondary growth forest, grassland habitat, and an organic fruit orchard provide a variety of habitats and hence a very high diversity of flora and fauna species. Our site is adjacent to the Sibun Forest Reserve which together with several other reserves forms the Southern block of protected areas in Belize, consisting of thousands of hectares of intact contiguous tropical forest. We have kms of trails running throughout the site and in the making is a 4-day hiking trail that goes up into the Sibun Forest Reserve in the mountains (at about 1000 m elevation).
T.R.E.E.S cabins and Maya mountains
Dry Creek that runs through T.R.E.E.S 
Our remote cameras have shown dozens of different large mammal species present on our site, including jaguar, margay, tayra, armadillos, agoutis, brocket deer, pacas, and skunks. Live trapping of small mammals and mist-netting of bats have added several species of small mammals, including several individual mouse opossums. At least 9 fish species have been identified in the river systems, more than 40 species of reptiles and amphibians have been observed on site to date (including many endemic and endangered species), and our bird list now numbers over 150 species.
Map of Belize (star is T.R.E.E.S)

Freshwater fish from Dry Creek

Mouse possum
Jaguar on field cam

Blue-spotted Treefrog (Endangered)
Royal Flycatcher
White Hawk

We can host groups of up to 30 students with accompanying professors for faculty-led field courses but we also offer our facilities to undergraduate students interested in internships or volunteer work, or graduate students pursuing studies in tropical ecology. That is where the NEO program comes in!
To graduate students we offer field equipment for stream sampling (including minnow traps, D-frame kick nets), mist-netting of birds and bats, and small mammal trapping. Starting March 2014 we will setting up a bird-banding station that will run as a long-term monitoring site for migratory and resident bird species. Long-term herp monitoring projects for frogs and turtles is also underway.

Bird bag Christmas Tree

Belize, although not officially Spanish-speaking, is a country in Latin America and as such is an excellent location for NEO students to conduct graduate studies in ecology, community development, political science, and resource management. We work with professors from the University of Belize and Galen University that can act as co-supervisors for students in NEO. My partner and I (both biologists) are also at the T.R.E.E.S field station the better part of the year to help students on projects.

 If you or anyone you know might be interested in conducting research based out of T.R.E.E.S in Belize and would like more information, I invite you to see our talk at the Redpath Museum at 11:30 am this coming Friday, September 20th. You can also check out our website at www.treesociety.org or email me directly at vkilburn@treesociety.org.

I am looking forward to being part of the NEO program again!

Vanessa Kilburn
Director and Program Manager,
T.R.E.E.S (Toucan Ridge Ecology and Education Society) 

NEO graduate 2008 (Herpetology)
Supervisor Dr. David M. Green

Friday, 6 September 2013

Food or Poison

“Often there is not even a thin line between a food plant, a toxic plant and a medicine”
Marjorie Grant Whiting, 1962

Its all a matter of dosage” they say.

Lets take an example from a common medicinal compound, like codeine. Codeine is one of the opioid alkaloids produced by the poppy plant and can be detected in the human blood after eating a poppy seed bagel. Its magical powers (activating opioid receptors) justify the extensive use of codeine as a painkiller, analgesic, antidepressive, sedative and cough relieve. However at very high doses codeine will kill you by respiratory depression. The importance of dosage can be observed in many relationships between humans and plants. While the dosage issue might come off as common knowledge for many, we drinkers like our plant brews and distillates in the rage of 4 – 40 % alcohol, the parallels to other plant-animal interactions might not be so obvious.

After studying a beetle that loves cycad toxins, we might have found parallels to the human relationship to medicinal/drug plants. The beetles seek out the cycad plant when the new foliage is being produced and voraciously feed and mate on the plant. They actually sequester the cycads toxins as means of defense and upon threat they will expose a drop of hemolymph from the leg-joints. The tiny drop of hemolymph contains high concentrations of the plant toxins. This surely shows that the beetle is a cycad specialist and can deal with the plant’s toxicity. But when we looked at the relationship a bit closer we found that the insect does not feed on the leaves with highest concentrations of toxins as we predicted. They rather choose a lower range of dosage from which they take their fix. Our data suggest that the high concentrations are still protecting the youngest leaves even from these cycad-loving beetles. Just as in the human-plant interactions, the beetle benefits from a particular chemical compound present in the plant but only at a certain dosage.

The dosage dependent manner of plant-animal relationships is probably based on the enzymatic capacity of the animal in question. Intoxication arises from saturation of the detox capacity of the herbivore.

So why doesn't the plant produce more of these toxins if they are so effective? Well, no one really knows, but it could be due to the cost of production or a matter of autotoxicity. The plant cells are also vulnerable to the deleterious effects of these toxins if they are not properly controlled.
And why doesn't the insect increase its enzymatic capacity to be able to feed on the most toxic leaves? Maybe there is no need, we have not observed any predator feasting on these aposematic beetles despite their local abundance.
Plants produce a plethora of secondary metabolites many with the ability to deter herbivores and pathogens. Sometimes the same compounds that effectively deter one set of organisms will be mediating the interactions with others. How do these plant-insect relationships arise? Why are some insect groups more prone to tolerating a specific type of plant chemistry?
So many questions to explore, so many lessons to be learned.    

Photo credits: Don Windsor and Guillaume Dury.