Invasive Species Take Over of the Guadiana River in Spain

October 20, 2012


Photographer: Juan Manuel Perez Rayego
Summary Authors: Juan Manuel Perez Rayego; Jim Foster

Since 2004, a water hyacinth, native to the Amazon Basin of South America, has become a huge nuisance in the Guadiana River (shown above) of south central Spain. Camalote (Eichhomia crassipes) is included in the list of most damaging alien species in the world by the International Union for the Conservation of Nature. Widely used as an ornamental aquatic plant  for ponds and aquariums, it thrives even in the mid-latitudes, where few flora or fauna seem to be able to prevent its spread. In Western Europe, especially in Italy, Portugal and Spain, it’s abundant in a number of river basins, particularly during the warm summer months. It’s not known for sure just how these plants were introduced here. People actually can walk on the matted islands that these plants form. They tend to initially show up along constrictions or barriers in waterways, such as wires used to mark buoys, of which there are several along the stretch of the river where this photo was taken --  on October 5, 2012.

Photo details: Camera Maker: Canon; Camera Model: Canon EOS 5D; Lens: EF17-40mm f/4L USM; Focal Length: 19mm; Aperture: f/4.0; Exposure Time: 0.0031 s (1/320); ISO equiv: 200; Exposure Bias: -0.33 EV; Metering Mode: Spot; Exposure: aperture priority (semi-auto); White Balance: Auto; Flash Fired: No (enforced); Orientation: Normal; Color Space: Adobe RGB (1998); Software: Adobe Photoshop CS6 (Windows).