Transect locations and frequency
One 1-km transect is located in each vegetation zone near current
NPP study locations C-CALI, G-IBPE, M-NORT, P-COLL, and T-EAST.
The transects were established in one area in each of 5 habitats.
Three-meter lengths of rebar were driven into the soil at 50 m
intervals. Each length has a section of white PVC pipe attached to
the top to facilitate line of sight orientation by an observer. An
observer walked each transect once every two weeks from early 1989
through 1994.
Observation method
One observer walked each transect from segment 1 to 20. The
observer records all birds, rabbits, and lizards seen. The
distance of each animal from the transect line was also estimated
and recorded. Transects were walked in the morning hours only,
once every two weeks. The Emlen method (Emlen 1971) will be used
to estimate densities of each animal species at each site.
Observations were recorded onto field data sheets or tape
recorder. Taped data is transcribed to data sheets.
References
Emlen, J. T. 1971. Population densities of birds derived from
transect counts. Auk 88:323-342.
Raitt, R. J. and S. L. Pimm. 1976. Dynamics of bird communities in
the Chihuahuan Desert, New Mexico. The Condor 78:427-442.