Wednesday, December 19, 2012

Beavers in the retention pond (Part V)

What: I've just finished editing and touching up my students' entries to the Natural History Dictionary. Took a lot longer than I hoped, but it's certainly worth it. Definitely a work in progress, but I think it's shaping up to be something really really helpful and fascinating!!

So last Friday the kill traps went back up. UVM has killed at least one of the beavers so far, and another one went missing since last Thursday (with finishing up grading I haven't been able to spend as much time out there, so there very well could still be three left, but I was only been able to see/hear 2 last night; all the time spent grading means that this footage is all old). I'm not universally opposed to trapping, I just think in this case it's being done irresponsibly (ecologically and in terms of the community perspective), in a short-sighted way, and as a result of prior ineptitude.

UVM Grounds won't respond to my questions about the process involved or why it's so imperative to kill them - an unfortunate lack of transparency - so I'll speculate based on personal observation and what I've heard second hand. From what I gather the beavers have to go because part of the requirement for managing the retention pond (built as a mitigation for paving the parking lot next to the Centennial Field) includes monitoring and managing for both water quality and water height. Apparently they have to check these every month to meet legal obligations. Water height is an easy one, but I would assume they're either not doing it regularly or doing it poorly as the beavers have been there for 4.5 out of the last 7 months (a 2 month stretch from June to late July, and again from late September until now). Most of that time the water has been about 4' higher than normal.

As for pollution, I don't know how beavers being there would make any difference or what kind of pollution they'd be measuring (biological or chemical). It's not like any of the vegetation is doing any biofiltering of anything this time of year. And the volume of water flowing out should be the same as if the water were 5' lower. Beavers don't really carry rabies and there's never been a rodent-to-human infection, not that that should be a concern (if it was they'd probably want to do something about the raccoon population.

Beaver scat! A rare site! Basically it's just saw dust. This is from Mill Pond 
Humans are far more likely to carry giardia than beavers (beaver fever's a misnomer - most birds and mammals can carry the parasite, and people get giardia when they go camping usually not because they drink contaminated water but because their hygiene goes down the tubes). A study in the northeast found that muskrats had a prevalence of for trophozoites (the stage where the parasites is actually parasitizing, rather than just being transferred from beast to beast) of 96%!!! while for beavers it was less than 15%. There are two muskrats living in the lodge with the beavers and were here well before the beavers established their home and will be here well after (they don't share the same resource depletion strategy as beavers). It seems unreasonable that they'd be testing for Giardia sp., however, and I'm sure there's another reason why the beavers need to go. I'd love to know...

Where: Retention pond under powerlines in Centennial Woods

The amazing capacity of beech to stump sprout. Look at all those latent buds! 

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