Question

1. You are conducting a long term study of ecosystem functioning in a freshwater lake. You and your field assistants gather data for many biotic and abiotic factors, including species diversity, water and benthic quality, and turbidity. Over the ten years of your study, you find that the abundance of water lilies is correlated with several other factors. When water toxicity and turbidity are high and water pH is abnormally low, water lilies quickly become scarce, followed by periods where fish, amphibians, and water birds are also scarce or absent. In years water nutrient levels are very high, water lilies quickly become abundant, followed by years where wading birds are scarce. From these data, you conclude that water lilies are ________________. Choose the right answer and explain “why”.

A) An umbrella species because___________________________________________

B) A keystone species because ____________________________________________

C) An endemic species because ____________________________________________

D) A flagship species because _____________________________________________

E) An indicator species because ____________________________________________

Answer 1

It is an indicator species which tells about the health of the ecosystem. Less water lillies is an indication of the water being acidic, toxic and turbid. Because of these conditions, water lilies become abnormally low followed by other species also as they can't survive in such waters. But with the water becoming normal, water lilies increased in numbers and other species must have also increased numbers. All this indicates healthy habitat and ecosystem. So, by looking at the growth of the water lilies, we can decide how healthy the habitat is. Because the water lilies are growing, birds can't wade through the water. All these are just indicators of the health of the habitat. All put together, the health of the habitat can be diagnosed. So water lilies are indicator species.

Option E is the right choice.