In nature, decomposing carcasses release nutrients into the ground that can be taken up by nearby plants. And nutrient rich plants are generally more attractive to herbivores. So, does that mean that elephant carcasses can attract herbivores?
Last episode, I explained a bit about how we map the bonefields around a carcass site. But that’s not all we do here.
That metallic sound you’re hearing, a bit like maybe a railroad spike being driven into the ground, is actually me using a 20kg post pounder, which is a large tube with a heavy weight on the end, to ram a 5kg, 1.8m pole into the ground.
At this site, I’ll be doing that with another 15 poles.
It’s hard work. Combine it with the heat and the fact that we had to carry all this on our backs for kilometers across the savanna and you’ve got an interesting work day. Granted, the reason we’re doing all this is to try and better understand the ecological legacy of an elephant carcass. See, almost every carcass we’ve found has been encircled by a lush ‘halo’ of vegetation.
This is in part because a carcass contributes to the local nutrient pool enough that nearby plants absorb increased nutrients from the carcass site. What we want to know is, does this also lead to an increase in grazer visitation?
We think that it could because like humans in the supermarket, if given the choice, grazing mammals will also select the best-looking greens. And of course, grass grown in an area with better nutrients will look more appealing.
So, it’s possible these carcass sites are attractive as grazing sites. But we don’t know yet. Which is why I’m out here pounding metal into the ground. See after we install these polls, I’ll next connect them with metal mesh to create a series of ‘exclosures,’ at different distances from the carcass center.
These exclosures will prevent large mammals from entering. Then after a full growing season we’ll compare the dry weight of grasses grown inside the exclosures where no large mammals can enter, to their adjacent controls where grazers can easily access grass. That is, if they really ARE visiting these sites.
Combine these data with numerous camera traps and the dung and browse surveys we conduct while mapping bonefields, and we hope to get an idea of vertebrate visitation to elephant carcasses.
