Tamarisk is a thirsty plant with a high evapotranspiration rate, taking lots of water and releasing it into the air. It competes with native plants and can displace riparian habitat. Other than mature trees serving as nesting sites for the Southwestern Willow Flycatcher, it contributes little food or other benefits to native animals. In Saguaro National Park tamarisk is under control, but in other western states, it has caused serious damage. It grows fast and forms thick stands creating large areas of dense shade. This shade discourages native seedlings, from trees to grasses, decreasing the diversity of plants and animals in the ecosystem. It increases fire frequency, changes streambed hydrology, lowers water tables, and increases soil salinity.