We can skip over the safety of having to climb out of the window well in case of emergency, just know that it is physically possible. The point is that we have a rather large and deep window well. Every year, starting around mid-summer, moles and frogs decide to make the window well their home (read they fall in). Normally I wouldn't care too much, but there are always a few dry leaves in the window well and the moles really love to run over and through these dry leaves starting at about 2AM. Again, I wouldn't normally care, except said window well is directly below the bedroom window right next to my side of the bed. You might be surprised how much freaking noise a 20 gram mole can make using just a few dry leaves in the middle of the night. (Just for the record, frogs are good neighbors and either sleep normal hours or are scared of dry leaves.) So on a fair number of nights every summer, Ill be outside in my slippers and sweatpants (you hope) with a flashlight, a large box, and a small garden rake. One can easily jump into the well, place the box on its side along the wall of the window well (the important thing is to make sure the flaps are open and not bent backwards), then using the rake and flashlight scare the mole around the edge of the wall and into the box. Once in simultaneously close the flaps and tip the box upright (This is actually your second attempt, because the first time the mole went into the box, it escaped while you were dicking around with the flaps, which you left folded backwards). Ensure the mole is in the box by give it a gentle shake (gentleness is inversely correlated to the number of hours I had already been asleep). Of course, it will take several attempts to actually get the damn mole into the box because the flap won't be tight against the wall and the mole will go behind the box, or there will be a small gap between the flap or box and the gravel at the bottom of the window well and the mole will go under it (The number of failed attempts at catching said mole also affects the degree of box shaking gentleness).
Evil mole of satan |
American Toad |
So 2010 has been an interesting year. Weather-wise there has been nothing remarkable and I have had to capture several moles this year. However, there have been virtually no toads/frogs in the window well, in fact I can only recall a single one.
So what gives? Damned if I know, but one thing I thought about was the rampant world-wide decimation of frogs populations particularly in tropical climes. Entire ecosystems are being upended rapidly because once frogs are gone, animals that feed on frogs are not far behind, also animals that frogs feed on flourish (aka insects), which causes additional disruptions.
The question immediately on your mind Im sure is, "why are frogs populations crashing?" Great question, it turns out the culprit is a fungus called Batrachochytrium dendrobatidis. B. dendrobatidis is a member of the chytridiomycota, aka the chytrids. These are extremely cool fungi (apart from the killing all the amphibians part). They are quite distantly related to the fungi we commonly think about which are Ascomycetes (eg Bakers yeast) and Basidiomycetes (eg Shitake mushrooms). Moreover they are motile!! That's right these SoBs will come to you. Actually it is the spores (zoospores) that are motile via a flagella, not the vegetative cells, but still I expect people in general would state that fungi are non-motile (because most are), but biology is ripe with awesomeness because there is always an exception.
Ok, but Minnesota is generally not considered a tropical clime, so what's a single season lack of frogs in my window well got to do with B. dendrobatidis? Probably nothing, but thinking is fun. A quick google search for B. dendrobatidis and Minnesota came up with this paper (Prevalence of the pathogenic chytrid fungus Batrachochytrium dendrobatidis, in an endangered population of northern leopard frogs, Rana pipiens). It turns out B. dendrobatidis is associated with a reasonable number of frogs in Minnesota! Now at this point there is no indication that B. dendrobatidis is negatively affecting frogs here, but this may be something to keep an eye on.
Bd is not the only cause of amphibian declines but it seems to be the culprit in most of the cases that are otherwise mysterious. It definitely occurs in temperate climates, including Canada and the US and has been implicated in the many instances of population crashes observed in multiple frog species in western North America. Interestingly, it is not viable in hot weather. The affected tropical frogs are mostly those that occur in cooler climates at higher elevations.
ReplyDeleteThanks Matt. I knew the Bd was primarily found at higher elevations in the tropics but was unaware Bd was problematic in Western NA. Once interesting point is that the cause of death is still not known, I think the leading hypothesis is that Bd interferes with respiration though the skin.
ReplyDeleteSome of my professors when when I was studying in New Zealand were working on BD...very cool (but destructive). The proposed evolution of the organism is kinda crazy.
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