After a great deal of thought, this is what I came up with:



It is a combination of several factors.



1) Box Turtles are homers for sure, but that doesn't mean their home range isn't rather large. I'm going to say, that they are seasonally migrational, much the same as has been proven with several Rattlesnake species. With the proliferation of roadways and the increased frequency of vehicles traveling those roads, Box Turtle mortality has been high for several decades. Lets not forget the habitat destruction/modification driving them out and causing them to move and cross roadways, as well.



2) I'd have to say, in conjunction to the range limiting factors, that DDT or some other long term cumulative pesticide/toxin has resulted in multiple years of breeding failure.



3) If an ordinary Box Turtle has an ordinary lifespan of 40 years, with a reproductive life of 32 to 35 years and breedings are at a high probability of failure, the results would be negative population growth until extinction.



4) As population densities decline over time, adults are required to travel greater distances in order to find a mate, and in so doing the probability of vehicular homicide becomes more likely. Amounts to a population death spiral.



Has anyone studied pesticide/toxins in Box Turtle tissue?



jsc
-----
"As hard as I've tried, just can't NOT do this"

John Crickmer

[ Reply To This Message ] [ Subscribe to this Thread ] [ Hide Replies ]