Lesson 14 of 22
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Vegetation in the Watershed

February 14, 2023

What is vegetation?

Vegetation is a fancy way of saying plants and algae, including trees, shrubs, bushes, forbs (flowering plants), grasses, and mosses. It’s important to have vegetation near a stream or water source for these reasons. Vegetation along streams:

  • Provides habitat in the water for fish and macro-invertebrates.
  • Cools water. Cooler water means more oxygen, thus more life in the water such as fish and insects that are important for stream ecology.
  • Provides shade which keeps banks cool allowing fish to hide during the hot times of the day.
  • Holds in moisture through root systems, helps prevent flooding, and reduces soil erosion.
  • Provides habitat for small animals and insects and food for creatures like deer and elk.
  • Creates more stability for banks and slopes.

When there is a lack of vegetation, there are less creatures in and around the water, and soil becomes disturbed, washing away when there is a rainstorm. However, not all vegetation is helpful!

Invasive vs Native Vegetation:

Not all plants are from this region of the world but they end up here, usually through people bringing them. These are considered non-native species. When a plant has evolved in harsh conditions for thousands of years and comes to a new place, it can out-compete the other plants and therefore become “invasive”. There are plenty of plants that are not native but co-exist pretty well and can be known as “adapted” or “naturalized”, but these plants don’t tend to compete with our native plants. Native plants are special because they have been part of the ecosystem for thousands of years. This means that native wildlife and insects rely on them for survival and without them, the whole ecological community can collapse.

Let’s look at some invasive plants:

Russian Thistle or Tumbleweed: You’ve probably seen this plant as it commonly tumbles through the landscape in New Mexico. Tumbleweeds  are invasive and  considered “noxious” meaning that they take an entire area up quickly because they are so competitive. This picture shows how big they can get in just one year of growth!

Russian olive: This invasive tree prefers areas near water and can be seen crowding a river bank near you. Russia olives were originally brought to the United States for the ornamental turquoise color of their leaves. They grow fast with little water, causing the native cottonwoods and willow populations to fall behind.

Tamarisk or Salt Cedar: This tree was introduced for its beauty and heartiness. Unfortunately, it also invades stream areas such as the Rio Grande ecosystem, crowding out native plants. It is called “salt cedar” because it holds salt in its leaves and trunk and secretes salt into the soil, which is not good for the microbes or surrounding plants. It also grows many branches and leaves and becomes a fire hazard.

Large green shrub with feathery green branches some with pink tips.

Now let’s take a look at some native plants:

Ponderosa Pine: This tree is common in northern New Mexico and is usually found on rocky mountain slopes. One way to determine if you have found a ponderosa in the woods is to count the number of needles on each bundle – there should be three long needles per bunch. Sometimes the giant trunks smell like vanilla!

Red Willow: This is often found near water. It is the tree with the red bark along rivers that you may especially notice in winter when the leaves have fallen and the red bark is more visible. It is a very important species for animal habitat and diet; for example deer need it to survive through the winter. Pueblo people have also used this plant for many things because of it flexibility, like basket and bow making.

Coyote Gourd or Buffalo Gourd: This viny squash cousin is also known as stink weed because it has a strong smell and nothing seems to eat its squash (apparently the young squash can be eaten, but they do not taste very good because of bitter tannins in the skin). It is a native plant that the pollinators enjoy. You have probably spotted this one growing in dry spots or near an arroyo.