Past, Present and Future

There is more to surviving climate change then just being able to keep up.  You must be able to survive the chaos as ecosystems dissolve and reshuffle if you are going make it.  Simply looking at an organism’s ability to move is inefficient in assessing risk.  Other criteria should be added to the tools ecologists use to assess risk based on an organism’s ecological entanglement.  The fossil record is pretty clear that ecosystems don’t stay together and the tight relationship most ecological specialists have with their current ecosystem puts them at a great disadvantage.  

Canadian Lynx with Snowshoe Hare

The specialty seen in the Canadian Lynx today seems to be the driving force behind its divergence from its ancestral relatives. The Canadian Lynx’s ancestor diverged from the bobcat about 1.6 million years ago right around when the cooling that proceeded the last ice age really kicked into gear.  This divergence was accompanied with a migration north, out of the middle of North America, and back into Canada and Alaska. Later, around 1.2 mya, the Canadian Lynx diverged from the ancestral Lynx who continued north and out of North America entirely, while the Canadian Lynx stayed behind.9 The Eurasian Lynx, Lynx lynx, is one of two Lynx surviving today that descended from the ancestral Lynx after it crossed back into Asia. They are generalists, about twice the size of the Canadian lynx, who live historically all over Europe and Asia and eat a very diverse assortment of prey, much like the bobcat.14  When you look at the Lynx family tree flexible diets and diverse habitats seems to be family traits and may better represent the ancestral Lynx. This means that the extreme adaptions of the Canadian Lynx are all highly derived and no ones fault but its own.

Eurasian Lynx

While both the Lynx and the bobcat represent populations that remained behind while their sister taxa moved on, it is unclear if this was simple allopatric speciation or a more complicated sympatric divergence that sent the migrating Lynx off chasing its prey.  Regardless of what spawned the speciation events, the bobcat seems to have retained its flexible nature, while the Canadian Lynx purged versatility for increased performance in the snow. The lynx show a narrower range of body sizes, it inhabits only very particular types of habitats and is a very picky eater.    Now that the world is warming and looks headed for an earth without permanent ice or lasting snow cover20, the Canadian Lynx’s million plus years of selection for performance in snow will all become for naught.

Based on biome mapping from Loarie et al 2009

A case could be made that the bobcat’s flexibility is its greatest asset. Bobcat is about as general of a generalist as you will find for a hyper carnivore. It combines flexibility in behavior, environment and phenology which should keep it thriving no matter how the world changes around it. The Lynx on the other hand is about as entwined with both its environment, and its primary prey, as you can get and should be considered greatly at risk despite it falling outside current risk assessment parameters. This blog has tried to show how each level of intertwinement adds another layer of risk in the face of climate change.

Data from Kobalenko, J. Forest Cats of North America

Data from Kobalenko, J. Forest Cats of North America

 

Lynx Tracks Photo from Moosecountrysafaris.com
Eurasian lynx photo from tolweb.org. original credit to Ulrike Brutting
Lynx photo from Arkive.org