Grantee Research Project Results
Adaptation of White Sands Pupfish (Cyprinodon tularosa) to Different EnvironmentsEPA Grant Number: U915976
Title: Adaptation of White Sands Pupfish (Cyprinodon tularosa) to Different Environments
Investigators: Collyer, Michael L.
Institution: North Dakota State University Main Campus
EPA Project Officer: Graham, Karen
Project Period: January 1, 2001 through January 1, 2004
Project Amount: $73,077
RFA: STAR Graduate Fellowships (2001)
Research Category: Fellowship - Zoology , Academic Fellowships , Biology/Life Sciences
The objective of this research project is to show that the creation of White Sands pupfish (Cyprinodon tularosa) refuge populations in environments that differ from native environments can have large evolutionary consequences. Conservation management of pupfishes (C. tularosa) of North American deserts typically involves efforts to preserve native habitats and create refuge populations. The latter approach is used as a safeguard in the event that a catastrophic event should result in the local extinction of a natural, native pupfish population. The White Sands pupfish is composed of four wild populations representing two native and two introduced populations in two saline river and two brackish spring aquatic habitats: Malpais Spring (native, brackish spring), Salt Creek (native, saline river), Lost River (introduced, saline river), and Mound Spring (introduced, brackish spring). Introduced populations were established circa 1970 from translocation of fish from the Salt Creek population. In the three decades since it was established, the Mound Spring population has become the most morphologically distinct, having a deep-bodied shape compared to the streamlined shape of its founding population, Salt Creek.Approach:
Through a common garden experiment with native populations, I found that body shape has a strongly genetic signal. Therefore, the streamlined shape of Salt Creek fish and the deep-bodied shape of Malpais Spring fish appear to be adaptive. To test this possibility, I created several experimental populations of fish from Salt Creek and Lost River in brackish ponds that mimicked the natural conditions of Malpias Spring and Mound Spring. This experiment was a recreation of the introduction of Salt Creek fish to Mound Spring approximately 30 years prior. I analyzed the covariation of growth and body shape for natural populations and offspring from experimental populations. I found that: (1) approximately one-third of the introduced populations did not survive introduction (possibly from parasite infection); and (2) experimental populations did not significantly diverge from source populations in shape and growth, suggesting that these traits are adaptive, not plastic. The results of this research project show that pupfish morphology may undergo rapid evolutionary divergence. Because refuge populations should represent evolutionarily, unequivocal replication of native populations, the introduction of pupfishes to environments that differ from their native habitats may not be an efficient conservation strategy.Supplemental Keywords:
fellowship, White Sands pupfish, Cyprinodon tularosa, native pupfish population, conservation management, conservation strategy, native habitats, refuge populations.