They assist in identifying the main environmental stressors or threats, appropriate indicators of ecosystem health, and relations or linkages between the stressors and the indicators. Additionally, conceptual models are an important tool for communicating how complex ecologic systems work, the ecologic and physicochemical interactions between the various components, and which components and linkages might be targeted by specific management actions (Jorgensen 1988; Newton and others 1998; Gross 2003; Downs and others 2005)