I like to think of the range and population densities of bird species as three-dimensional feathered amoebas slowly inching their way across the surface of the globe.
The range, or distribution, of a species is rarely static for very long. Rather, it is continually changing, much like the movements of an amoeba, expanding in some directions and contracting in others in response to changing environmental conditions or other stimuli. The rate of range change is inherently variable from one species to another; some are inherently fast (relatively speaking), others inherently slow (perhaps even static).
Similarly, population density is not uniformly constant across the range of a species, but is constantly changing. Population density may be increasing (rising or thickening) in parts of the range where conditions are favorable for production of young and survivorship, while at the same moment in time it is declining (falling or flattening) in those parts of the range where conditions are less favorable.
For any given species, expansions and contractions of range and increases and declines in population density are all going on simultaneously, so it’s range and population density are constantly in a state of flux, in much the same manner as a shape-shifting amoeba. It is in trying to detect and monitor these amoebic shifts in range and changes in population density that amateur field ornithologists make their most useful (indeed, essential) contributions to science.
Popular Posts
-
Y ahora con Tristan Scott: Y ahora nuestros chicos de manera conjunta: ...
-
La foto delos 15, no mentiras la del documento de identidad, o certificado de votaciones Esta si es de colección, modelando para Dylan Ross...
-
Bueno y ahora un recorrido especial (que bueno hacerlo en la piel de los chicos) por la historia fotográfica de ELIJAH y MILO.. Un amigo ...
-
If you live in the Bay area, you're probably well acquainted with, the Berkley based , Omega Too . For the rest of you, they're the...
-
Eric Martsolf is an actor and singer who starred as Ethan Winthrop in the American soap Passions up until 2008. He is now playing the role o...
-
Selected stories about culled from the world's newspapers and other news outlets, particularly as it relates to wild birds, as gathered ...
Subscribe to:
Post Comments (Atom)
No comments:
Post a Comment