In conventional ecosystem models, the parameters are considered to be deterministic. But in reality, they are not deterministic rather than imprecise in nature. This book presents different types of food chain models under imprecise parameters that are handled by fuzzy set theory. The main feature of this book is to study different ecological models in fuzzy environment. Different fuzzy mathematical techniques are described in this book to study the fuzzy uncertain ecological models. In the present book, important ecological models are constructed with realistic scenarios to give the readers and researchers a deep insight of their effects in our ecological systems.