[Reading note] When catastroph happens: which role does spatial connectivity play?


September 15, 2022

My colleagues here in Montpellier did some cool stuff on spatial connectivity of ecological communities. They look at different patches of local communities, which are connected by dispersal (this kind of system is called meta-community). They asked: when extinction happens in some patches, if all these patches are clustered in space, how does it influence the whole system, comparing to if these patches are rather evenly spreading in the space? 
So, imagining in your garden: at one corner of the garden, all the grasshoppers disappeared because your little boy caught all of them to do funny experiments (scenario 1). Or, your little body decided to catch them in different spots of the garden, but the total area of his harvest is the same as the first scenario (scenario 2). 
Now, how do you expect: in which scenario would the grasshopper community in your garden recover sooner from such catastrophe? 
Well, my colleagues did some lab experiments using cute ciliates, as well as computer simulations, to discover. They found that when the areas of extinction are aggregated in space, it takes longer for the whole system to recover. Imagine scenario 1 of your garden: it takes longer for the surviving grasshoppers to travel to and to re-occupy the big corner area where extinction happened. In contrast, if the catastrophe is scattered in small spots in space, it is quicker for the grasshoppers nearby to re-occupy these spots and do their lives again (I mean, to reproduce, etc), so the system comes back to its prosperity sooner.
So, did you get the right answer? See you in the next digest!
For the paper see: Camille et al., 2022 https://royalsocietypublishing.org/doi/abs/10.1098/rspb.2022.0543