Nature’s Notebook: Precipitating Growth: Catalina’s rainy days are welcome

0
484

It’s human nature to grumble when it rains. But anyone who’s lived through a drought season on Catalina knows that rain is something to be celebrated here.

While all dry climates rely on rain, islands are more vulnerable to shifts in weather. A couple of dry seasons in a row can really impact the Island and, unlike mainland communities, we can’t look further upstream or a hundred miles away for another supply of water. If rain doesn’t fall from the sky, we get pretty thirsty pretty fast.

It’s human nature to grumble when it rains. But anyone who’s lived through a drought season on Catalina knows that rain is something to be celebrated here.

While all dry climates rely on rain, islands are more vulnerable to shifts in weather. A couple of dry seasons in a row can really impact the Island and, unlike mainland communities, we can’t look further upstream or a hundred miles away for another supply of water. If rain doesn’t fall from the sky, we get pretty thirsty pretty fast.

Of course, every living thing on this Island is affected by rain. And December is a great time to see how true this is. If we receive just a few good rainfalls, the Island will green up at an amazing rate.

Plants that went dormant in the heat of the summer will suddenly be triggered by moisture, and the greening begins. But of course you need rain and light to really get things going and by early spring plants respond to the one two punch with an explosion of life.

When that explosion happens, all of the birds, insects and animals living in that habitat come along for the ride.

But what happens when the rains don’t come?

Catalina’s plants and animals have developed mechanisms and behaviors to get them through dry times. Some plants developed waxy or hairy leaves that reduce evaporation.

Others can just go dormant and wait things out. For example, if a drought gets severe enough, Catalina’s oaks can drop all of their leaves to prevent water from evaporating and then grow new leaves when the rains return. Plants with this adaptation are referred to as “drought deciduous.”

Some of our animals can even get through lean water times on what’s called “metabolic water.” That means they can get much (and in some cases, all) of the water they need from just the food they eat. Our Catalina Island foxes will switch their diet in the dry season and eat more moisture-rich cactus fruits until the rains bring relief.

Frank Hein is director of education for the Catalina Island Conservancy.

Nature’s Notebook: Precipitating Growth: Catalina’s rainy days are welcome