We have a new paper out in the journal Methods in Ecology and Evolution:
http://onlinelibrary.wiley.com/doi/10.1111/j.2041-210X.2011.00183.x/abstract#.Tvt1QWJ0ql0
One of the biggest problems studying seed dispersal is that seeds are hard to follow! With traditional seed tagging methods, many seeds simply cannot be found, especially when they travel long distances. One method researchers have used is to limit their search to a reasonable distance and track all the seeds within that radius. The problem with this method is that it tells one little/nothing about long distance dispersal. Given that long distance dispersal is believed to be particularly important, this lack of information is problematic. Patrick Jansen and colleagues developed a statistical method to reconstruct the shape of the tail of the seed dispersal distribution using the shape of the distribution inside the search radius. We thought this was a cool method and had the potential to be used more widely. Unfortunately, this method had never been tested with empirical data. Fortunately, we had a perfect dataset to test the method because we used radio-transmitters to track seeds in our project. We also decided to give it a name: the Censored Tail Reconstruction method (CTR). In general, we found that the CTR method worked exceptionally well at recreating the long-tail of the seed dispersal distribution. On the other hand, this method was highly sensitive to which mathematical function was used in the method, and what percentage of seeds were ‘overlooked’ by researchers searching for seeds. The upshot of our paper is that it is possible to calculate fairly accurate dispersal kernels using censored data collected with traditional low priced tagging methods. The caveat to this is that researchers need to be certain that they are able to find the vast majority of seeds within their search radius, and they must choose the most appropriate mathematical function for use in the CTR method (using AIC selection). We think this method should be widely adopted, especially by researchers who cannot afford tons of radio-transmitters.
March 8, 2012 at 09:09
Can you tell me how you catch agoutis? The island of Montserrat has too many of them. They destroy garden crops so people are unable to eat. They are hard to catch and poison is not the most desirable option.
March 18, 2012 at 21:31
They are very difficult to catch. We use a combination of coconut and bananas, and let them get used to the trap for a while before we actually set it.
April 8, 2012 at 22:15
One important technique is to spread plenty of bait around the trap. When using smelly bait (i.e. bananas) the more bait spread near the trap increases the ease of olfactory detection. Once the agoutis (or other animals) get used to the novel food outside the trap, and really learn to love it, then they’ll be more inclined to risk entering the traps for these highly prized foods.