PARENT SESSION
Symposium #10: Every Last Drop: Ecology, Conservation, and Restoration of North American Springs Ecosystems.

Organized by: LE Stevens and VJ Meretsky
Tuesday, August 6. 8:00 AM to 11:30 AM. Turquoise Ballroom, TCC.

Springs as keystone habitats: a case study from the Arizona Strip.

Perla, Bianca^*,1, Stevens, Lawrence^1,2, Burke, Kelly¹, Johnson, R.J.^2,3, ¹ Grand Canyon Wildlands Council, Flagstaff, AZ, 86001² Stevens Ecological Consulting, Flagstaff, AZ³ Geosciences Consulting, Boulder City, NV

ABSTRACT- Springs of the Arizona Strip concentrate biological activity and diversity compared to surrounding landscapes. We surveyed 100 springs on the Arizona Strip, north of the Colorado River, totaling 32 ha and approximately 0.002% of the 2,017,795 ha Arizona Strip. We recorded 128 bird species, 24 reptile and amphibian species, 45 mammal species and 525 plant species at springs, seeps, and natural ponds. This represents about 30% of the flora and fauna of the region. The number and type of species observed at springs were significantly higher and different from surrounding control habitats. Eleven percent of the flora on the Arizona Strip is restricted to springs. We also recorded several endemic invertebrate species and 2 vertebrate species found only at natural water sources. Springs may serve as refugia for some species, especially during dry years. Factors affecting species richness at springs included: elevation, discharge, total area, vegetation structure, area of water present and distance between water sources. Vertebrate species used springs regardless of habitat quality, water quality, or extent of development, as long as open water was available, and birds do not appear to be good indicators of site quality. Rarity and isolation of springs may prevent vertebrates from choosing high quality over low quality springs. Dry springs and springs with water piped from the source had significantly lower species diversity. These results indicate that springs are keystone habitats in arid environments that, despite their limited total area, they disproportionately affect a large number of species. Therefore, springs are targets for conservation, restoration and increased protection.

KEY WORDS: springs, biological diversity, refugia, keystone habitat