8172

• UCREFRP Catalog Number: 8172
• Author: Jacobi, G. Z., J. E. Sublette, S. J. Herrmann, D. E. Cowley and M. D. Hatch.
• Title: Final Report
• USFW Year: 1998.
• USFW - Doc Type: Investigations of an Index of Biotic Integrity in New Mexico.
• Copyright Material: NO

from a number of sites in the upper Rio
Grande drainage of New Mexico.
The objectives of the present study are: (1)
identify preferred data analysis methods by
analyzing a subset of data confined to the
upper Rio Grande drainage, (2) identify
aquatic ecoregions within the upper Rio
Grande drainage and (a) elucidate
. -environmental • factors-- that-characterize the
ecoregions, and (b) assess the utility of
aquatic ecoregion classification as opposed
to Hydrologic Units, (3) identify
chironomid, benthic macroinvertebrate, and
fish "faunal regions" and determine if they
are consistent with the aquatic ecoregions
identified with enviroi data, (4)
characterize associations of chironomid
species, benthic macroinvertebrate taxa, and
fish species, and (5) initiate a search for
summary statistics that may provide
important information about environmental
integrity and may warrant inchision in IBIS.
Methods
Study Area
The study area for this report included,
aquatic stream habitats within the upper Rio
Grande drainage of New Mexico. Three
drainage basins within the upper Rio
Grande drainage were studied, i.e., (1) the
mainstream Rio Grande and its tributaries
upstream from the Cbama River confluence,
(2) the Chama River drainage, and (3) the
Jemez River drainage. Habitats sampled
ranged from 5410' to 10520' in elevation.
The study area was bounded by the
Continental Divide on the west, the
Canadian and Pecos River drainages to the
east, and the New Mexico-Colorado border
on the north. The study area was bounded
on the south by the upper end of Cochiti
Lake on the Rio Grande and San Ysidro on
the Jemez River drainage.
Data CoUnfion
Field collection of floating chironomid
Pupal exuviae was'accomplished by dipping
a fine mesh hand net (280 micron mesh
netting) into the water where pupal exuviae
accumulated (e.g., eddy currents, behind
rocks, logs, and diversions). Water,
organic detritus, and floating pupal exuviae
flowed into the net as one edge was dipped
beneath the surface of the water. After the
net bad filled, the contents of the net were
emptied directly into a jar of 75% ethanol.
Collection was repeated until a large amount
of detritus and pupal exuviae were obtained.
Collection information was printed on a
label and included with the sample.
Pupal exuviae samples were sorted in the
laboratory by pouring aliquots of the sample
into a Petri dish and inspecting the dish for
exuviae using a dissecting microscope set at
12X magnification. Individual exuviae
were picked from the dish and placed into a
small vial. Up to 100 specimens of each
sample were slide-mounted to provide
analytical material and the remainder of the
sample was preserved as voucher specimens
for future studies. Generic keys given in
Coffman and Ferrington (1984) and
Wiederholm (1986) were used for
Chironomidae pupal exuviae identification.
Field collections of immature stages of
stoneflies (Plecoptera), mayflies
(Ephemeroptera), caddisflies (Trichoptera),
and otter orders of benthic
macroinvertebrates were accomplished by

2