Final answer:
Amphibian species are highly sensitive to acid deposition because they have permeable skin that absorbs pollutants directly from their environment. This vulnerability is heightened by additional factors such as habitat loss, climate change, and disease synergies. These threats not only diminish amphibian populations but also indicate more severe underlying ecosystem damages.
Step-by-step explanation:
Acid deposition most severely affects amphibian species because their skin is highly permeable, making them exceptionally sensitive to pollution. Amphibians, like frogs, are often seen as environmental indicators because their population decline can signal larger ecosystem issues. The risks amphibians face from acid rain are compounded by other human-induced problems such as habitat destruction, climate change, introduction of invasive species, and pollution which can all decrease the viability of amphibian populations.
Several factors explain why amphibians are vulnerable: pollution through permeable skin, climate change synergizing with fungal diseases, and habitat modification impeding their life cycles. The loss of amphibian species due to environmental degradation suggests deeper ecological problems, as amphibians play crucial roles in food webs and ecosystems. High levels of pollution and acid rain can weaken amphibian immune systems, making them more susceptible to diseases like the chytrid fungus which has been linked to global amphibian declines.