Ecological Archives A019-065-A3

Ghislain Rompré, W. Douglas Robinson, André Desrochers, and George Angehr. 2009. Predicting declines in avian species richness under nonrandom patterns of habitat loss in a Neotropical landscape. Ecological Applications 19:1614–1627.

Appendix C. Example of two of the piecewise regression equation sets obtained from the modified species–area relationship prediction curves.

Set of Eq. C.1 corresponds to a prediction curve taken from habitat loss scenario Group 1 (i.e., Topography), while the set of Eq. C.2 corresponds to a prediction curve taken from habitat loss scenario Group 2 (i.e., Habitat loss to Agriculture). The algebraic forms of the piecewise regression equations are described in the Methods. Each set of equations represent the section of the curve which included the two breakpoints (not using the portion of x between the intercept and 98 km2); τ1 represents the first breakpoint (lower threshold) while τ2 represents the second breakpoint in the curve (higher threshold). See main text for details.

      (C.1)
    y = 54.72 + 0.14x,    if x < τ1  
    y = (54.72 + 0.14*578.1) + 0.42 (x – 578.1),     if τ1 < x < τ2  
    y = (54.72 + 0.14*578.1) + 0.42 (682.3 – 578.1) + 0.06 (x – 682.3),      if x > τ2  
       
       
    y = 27.74 + 0.11x,    if x < τ1 (C.2)
    y = (27.74 + 0.11*579.9) + 0.60 (x – 579.9),     if τ1 < x < τ2  
    y = (27.74 + 0.11*579.9) + 0.60 (690.5 – 579.9) + 0.17 (x – 690.5),      if x > τ2  

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