Puma Patches

New research is increasingly highlighting how pumas (also known as cougars or mountain lions) play a critical ecological role through a strategy known as "garden to hunt."

Pumas can be found almost everywhere, from the wildest wilderness to the urban neighborhoods of large cities. In fact, you'd never know it, but pumas frequently spend their days sleeping alongside popular hiking trails, then waking up at night to walk those same trails.

Pumas live in a wide variety of habitats from southern Canada to the tip of South America, yet most people will never see one. Part of the reason is that pumas have huge territories (a male's territory can reach 500 square miles), which means they are widely scattered and easily overlooked as an important part of an area's ecological health.

One of the things you might hear about pumas is that they are voracious killing machines with a taste for deer meat. This is mostly true, but far fewer people have done the math in their heads and thought about the implications of this "carnage."

It's estimated that each puma kills about 52 deer a year, and all together, pumas kill over 2 million pounds of animals every day! That's a lot, but let's look at it from a different perspective.

Pumas are technically "small cats" that eat relatively small amounts of meat at each meal and then struggle to defend a carcass from competitors and scavengers. As a result, 40% of the food they catch is stolen before they can eat it, which is very different than carnivores like bears or wolves that defend and eat almost an entire carcass before anyone else gets to nibble on leftover scraps.

What this means is that every large animal killed by a puma becomes a nutrient hotspot that powers a tiny island (what has been called a "cadaver decomposition island") of supercharged life. This includes everything from an explosion of microbes in the soil to an astounding 485 other species that share the bounty of a puma kill.

Over a puma's lifetime it will leave behind close to 500 hotspots of nutrient-rich soils and supercharged webs of life, and each hotspot lingers for years at a time. Furthermore, these enriched soils and explosions of microbial life provide a flush of essential macronutrients that are absorbed by plants, and these plants then grow bigger and faster and provide highly nutritious leaves that deer actively seek out.

What's incredible is that these hotspots are not randomly scattered over the landscape but are instead centered at key points, specifically the locations where pumas prefer to hunt. In essence, it could be said that pumas are carefully tending (or gardening) the landscape by fertilizing plants that recruit deer to the exact spots where it's easier to stalk and ambush them.

It's all-too easy to dismiss the carcasses left by pumas as small, fleeting moments in time, but in fact these nutrient pulses add up over many years to deeply impact both short-term food webs and the long-term shaping of the larger landscape. (As one overlooked example, tree seedlings struggle to become established where abundant herbs and their fallen leaves carpet the ground, but large decomposing carcasses create spots of bare soil where seedlings start to grow and produce patches of future forest.)

All this might have you wondering what happens when puma numbers begin to decline...and this is a question that scientists have started to ask as well.