So… one more story from Costa Rica.

We spent a day on the Sierpe River. I’m sure I mentioned that before. And in addition to many species of birds and dozens of squirrel monkeys swinging through the trees, we saw plants.

Of course we saw plants! Costa Rica is an awesomely verdant country. I could go back and spend a week just learning about the plants! But the day we spent on the Sierpe River, I saw one I recognized. Instantly.

It was a patch of water hyacinth, and I recognized it instantly because in Louisiana, water hyacinth–however beautiful–is a big problem. Water hyacinth does not fit harmoniously into our ecosystem. It is an invasive species that clogs our waterways and chokes out life in the water below.

So when I saw water hyacinth–a patch of it–in the Sierpe River, I reacted with alarm. But our guide, again the ever knowledgeable and fun-loving Diego, explained that in the Sierpe River, water hyacinth not only does not create problems, it is valued for its beauty and the shade it casts to create pockets of cooler water for the critters below.

The difference that makes a difference in this case is water movement. Our Louisiana bayous are very slow moving. Water hyacinth can easily form huge mats that cover far too much water and get far too thick. The Sierpe River, on the other hand, is a tidal river, which means the water is in constant movement. Although water hyacinth can form patches, those patches are constantly torn apart before they can form life-threatening mats.

That’s why it’s so important to understand relationships among species and environmental features in an ecosystem. What fits in harmoniously here, doesn’t necessarily there and can, indeed, be life threatening there. It has taken we humans far too long to attend to such things before moving species about, both accidentally and purposely.