The Rio Grande is part of an important migratory pathway for diverse bird species, and provides wintering and nesting ground for many of them. Birds are an important part of any ecosystem. Bird diversity has been identified as a good example of overall species diversity in an ecosystem, and a diversity of birds may indicate ecosystem health. Decreases in bird diversity over time can signal degrading ecosystem health.
How is it scored?
Bird diversity scores were calculated for each region using a Simpson's Diversity Index, calculated using the equation below. The result of the calculation iwas scaled to the score range of 0-100%.
Simpson’s Diversity Index Equation
Index=1-(Σni(ni-1) / N(N-1))
where:
ni= The number of organisms that belong to species i
N= The total number of organisms