Our friend the mesquite seems to pop up in the most unlikely of places. Mesquite, a genus which includes thorny desert shrubs/trees from various parts of the Americas, perhaps most clearly demonstrates the importance of context. It’s not that a species is inherently bad because it’s invasive. Or, to go as far as some naysayers, that to want to prevent or remove invasive species is a sign of xenophobia. What that argument glosses over, is that context is key. For example, mangos are delicious… unless you are allergic.
Mesquite has many admirable qualities. It has some pretty handy ethnobotanical uses. Its hard wood can be used for tools, arrow points, and decorative wood work. As a firewood, it burns slow, hot, and aromatic, making it the perfect fuel for one of humankind’s greatest creations, Texas BBQ. Honey produced from its flowers is also aromatic, and it produces nutritious fruits even in drought years, that can be an important food source. Flour made from the bean pods is high in calcium, magnesium, potassium, iron and zinc, and rich in the amino acid lysine. Mesquite is such a bad ass; it has three inch spines that can be used as tattoo needles!
In its native context, mesquite is a ecosystem architect – it is the structure that shapes the community around it. It is a defining member of many vegetative associations in the American southwest, from scrub savanas to riparian forests. It provides shade in the desert, an invaluable resource. Mesquite is deeply tap-rooted, stretching down to 200 ft below the soil surface to reach deep water resources. It then brings that water up to where desert herbivores can reach it, in the form of juicy leaves and fruit. But it also has many shallow roots, allowing it to take advantage of sudden rains, and reducing the impact of flash floods. Humans aren’t the only ones that enjoy the fruit produced by mesquite. Many desert animals, including rabbits and coyotes, rely on the fruit pods, which are high in sugar (16%) and protein (12%), and can be found even when other food is scarce. Yes, coyotes – in fact up to 80% of a coyotes diet in the winter is composed of mesquite pods.
Not only does mesquite provide food, it also provides food storage.The loggerhead shrike is particularly fond of impaling its victims on the mesquite’s imposing spines, to save for later. Mesquite is great!
But mesquite is NOT great everywhere. Multiple species of mesquite are problematic invasive species globally. Mesquite is listed as one of the 100 worst invasive species by the IUCN. In its invaded range, among species that have not co-evolved with it, mesquite can rapidly out-compete under-story plants, resulting in complete loss of grass cover. This is a problem if you eat grass for a living, or eat the creatures that eat grass. But losing grass cover also results in the erosion of delicate soils. It can form dense thorny thickets, blocking access to water for wildlife and livestock. Livestock find the fruit pods just as tasty as coyotes do, and for a time, mesquite was commonly planted as cattle feed. In invaded areas livestock can spread the seeds far and wide. In Hawaii, invasive mesquites are found in the arid regions of every single island, between sea level and 700 m. Hawaii! That is a long way from home for the iconic southwestern plant.
Once you notice mesquite, you see it everywhere. And when out of its native context, it is jarring. Try this: If you haven’t seen Lagaan, the Bollywood/cricket epic set during Victorian period of the British Raj in India, you probably should. In an early scene, the main character, a feisty young farmer, hides in the forest surrounding the British cantonment, scaring deer away from British officers on a hunt. The scene is shot in a beautiful historic location. But the forest surrounding the cantonment is new. Perhaps you will recognize our friend, mesquite?