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7572002 
Journal Article 
Eradication of invasive Tamarix ramosissima along a desert stream increases native fish density 
Kennedy, TA; Finlay, JC; Hobbie, SE 
2005 
Yes 
Ecological Applications
ISSN: 1051-0761
EISSN: 1939-5582 
15 
6 
2072-2083 
English 
Spring ecosystems of the western United States have high conservation value, particularly because of the highly endemic, and often endangered, fauna that they support. Refuges now protect these habitats from many of the human impacts that once threatened them, but invasive species often persist. Invasive saltcedar is ubiquitous along streams, rivers, and spring ecosystems of the western United States, yet the impact of saltcedar invasion on these ecosystems, or ecosystem response to its removal, have rarely been quantified. Along Jackrabbit Spring, a springbrook in Nevada that supports populations of two endangered fish (Ash Meadows pupfish and Ash Meadows speckled dace) as well as several exotic aquatic consumers, we quantified the response of aquatic consumers to large-scale saltcedar removal and identified the mechanism underlying consumer response to the removal. Clearing saltcedar from the riparian zone increased densities of native pupfish and exotic screw snails, but decreased the density of exotic crayfish. Positive effects of saltcedar removal on pupfish and snails occurred because saltcedar heavily shades the stream, greatly reducing the availability of algae for herbivores. This was confirmed by analyses of potential organic matter sources and consumer super(13)C: pupfish and snails, along with native dace and exotic mosquitofish, relied heavily on algae-derived carbon and not saltcedar-derived carbon. By contrast, crayfish delta super(13)C values mirrored algae delta super(13)C during summer, but in winter indicated reliance on allochthonous saltcedar litter that dominated organic inputs in saltcedar reaches and on algae-derived carbon where saltcedar was absent. The seasonal use of saltcedar by crayfish likely explains its negative response to saltcedar removal. Clearing saltcedar effectively restored the springbrook of Jackrabbit Spring to the conditions characteristic of native vegetation sites. Given the high conservation value of spring ecosystems and the potential conservation benefits of saltcedar removal that this research highlights, eradicating saltcedar from spring ecosystems of the western United States should clearly be a management priority. 
Crayfishes; Microbiology Abstracts C: Algology, Mycology & Protozoology; Sustainability Science Abstracts; ASFA 3: Aquatic Pollution & Environmental Quality; Ecology Abstracts; ASFA 1: Biological Sciences & Living Resources; Endemic species; Riparian environments; Human impact; Cambaridae; Freshwater crustaceans; herbivores; Vegetation; Tamarix ramosissima; Organic matter; Ecosystems; Consumers; Conservation; Human factors; Freshwater; Carbon isotopes; Sulfur dioxide; Water springs; Meadows; Freshwater fish; Habitat; Deserts; Streams; Introduced species; USA, Nevada; Dispersion; invasive species; Rare species; Population density; D 04705:Conservation; K 03410:Animal Diseases; Q5 08523:Conservation, wildlife management and recreation; M3 1010:Issues in Sustainable Development; Q1 08262:Geographical distribution