Cutaneous respiration
The skin of amphibians is a major site of respiration in all species for which measurements are available. Cutaneous respiration is the sole respiratory mode of lungless salamanders (family Plethodontidae) which lack lungs entirely yet constitute the largest family of salamanders. Cutaneous respiration in frogs and other amphibians may be the primary respiratory mode during colder temperatures.
Blanchard's cricket frog
Blanchard's cricket frogs have warty skin that is usually brown, gray, tan, or olive green, with darker bands of color on the legs. Their skin is also known to be extremely vascularized which can cause things to get through there bodies very fast and increase the effects of diseases they are exposed to. A dark, triangular mark between the eyes is frequently seen. They are small, growing to in length. They generally inhabit slow-moving or stagnant bodies of water, and are the most aquatic of tree frogs in North America. They hibernate during the cold months, emerging in late March or early April and beginning hibernation in late October. Breeding occurs from mid-May to mid-July, and females lay small clusters or single eggs. Tadpoles emerge in late summer. Breeding males have a metallic clicking call distinctive to the species. The subspecies is named after Frank N. Blanchard, a noted American herpetologist. Most commonly found in streams and wetlands for reproduction. Only a few last until the second breading season, if a breeding season isn't productive it can lead to a decrease in population for that area.
Blanchard's cricket frogs can be found through most of the Midwest United States, ranging from Michigan and Wisconsin in the north to southern Texas in the south and from Colorado in the west to West Virginia in the east. Although not listed at the federal level, Blanchard's cricket frogs are considered at risk in some states. It is an endangered species in Wisconsin, and is a threatened species in Michigan, due to a significant population decline since the late 1970's. Habitat loss, chemical contaminants, and competition for resources have been posited as reasons for this decline. Populations can still be found in the southern and western portions of Michigan's Lower Peninsula. "A. crepitans", including "A. c. blanchardi", is also considered endangered in Minnesota. It may also still be on Pelee Island, Ontario, Canada, but has not been reported since 1987. It was thought that competition among Bullfrogs caused a decrease in the population of Blanchard's cricket frog, however, after a study was conducted there was no evidence of this. In this study Bullfrog tadpoles were put together with Blanchard's cricket frog tadpoles, over the course of the study no evidence suggested that the Bullfrogs were taking enough resources to impact the cricket frogs.This eliminated the Bullfrog as a possible reason on why Blanchard's cricket frogs have decreased in certain areas where both species are present. In another study done about the immune defense traits of Blanchard's cricket frog found information about the reason for decline. This study showed that multiple factors can influence the immune system of the frog, for example water conductivity, water surface area, and ratio of natural to managed land. All of these factors were found to influence the skin microbiome of the frog, which will cause the immune system of the frog to decrease. While some decreases in population are due to chemical contaminants and competition for resources, the major reason for the decrease is still unknown.