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Toad eggs (NPS Photo by Thea Nordling) |
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Lately, news headlines nationwide have featured stories about amphibians with strange mutations like extra or missing limbs, even extra heads. Dramatic population decline and even extinction have also become prevalent problems. The reason for these trends is unclear. However, studies indicate that amphibians are sensitive to a variety of environmental problems.
An amphibian’s water-permeable skin makes it very vulnerable to both air and water borne pollutants. Increases in UV radiation may increase mortality of eggs and tadpoles of some species. Also, the metamorphosis between larval and adult stages is a delicate process that can be affected by environmental changes. Finally, since amphibians range over both terrestrial and aquatic territories, changes in either may affect populations.
Because of this sensitivity, amphibians have become “indicator species,” the health of which can be used to measure the health of an ecosystem. Thus far, neither mutations nor population declines have been observed at Arches, but their importance as an indicator species has made preserving amphibian habitat a priority for the National Park Service.
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