Home | Archives | About | Login | Submissions | Notify | Contact | Search
 ES Home > Vol. 7, No. 1 > Resp. 9

Copyright © 2003 by the author(s). Published here under license by The Resilience Alliance.

The following is the established format for referencing this article:
Robinson, D. 2003. Step function versus exponential distribution. Conservation Ecology 7(1): r9. [online] URL: http://www.consecol.org/vol7/iss1/resp9/

Response to Keitt et al 2000. "Detecting Critical Scales in Fragmented Landscapes"

Step Function versus Exponential Distribution

Donald Robinson

ESSA Technologies Ltd.

Published: March 28, 2003

An important point in the Discussion section of Keitt et al.'s (2000) article is worded in a misleading way:

"... for an organism to perceive the habitat distribution as a single, large, interconnected cluster, it must, in general, be capable of dispersing a distance of 45 km over inhospitable habitat and must have an average exponential dispersal distance of at least 15 km."

Is it not more accurate to say that the 45-km and 15-km transitions correspond to quite distinct hypotheses about dispersion behavior, rather than being different measures from the same underlying dynamic? The first value results from a step function and the second from an exponential function. The forms are quite different and thus require different analyses (Monte Carlo in the second case) to understand their attributes properly.


Responses to this article are invited. If accepted for publication, your response will be hyperlinked to the article. To submit a comment, follow this link. To read comments already accepted, follow this link.


Keitt, T., D. Urban, and B. T. Milne. 1997. Detecting critical scales in fragmented landscapes. Conservation Ecology 1(1): 4. [online] URL: http://www.consecol.org/Journal/vol1/iss1/art4

Address of Correspondent:
Donald Robinson
ESSA Technologies Ltd.
Third Floor
1765 West 8th Avenue
Vancouver, British Columbia, Canada, V6J 5C6
Phone: 604-535-1997

Home | Archives | About | Login | Submissions | Notify | Contact | Search