Santa Rita Experimental Range
The Santa
Rita Experimental Range is managed by the University of Arizona
as a research site. It hosts a variety of research
projects, including studies of cattle grazing impact, of nutrient
cycling in desert systems, and of the affects of invasive species. We
stayed at the isolated facilities in Florida Canyon (build, originally,
by the CCC in the 1930s), along a spring-fed stream, with a
well-equipped bunkhouse to ourselves. We explored habitats
extending from high-elevation forests out to the desert grasslands of
the bajada, visited with researchers and managers, and conducted our
second set of original research projects. (The image above is
derived from LandSat data; the mountains at the bottom (south) edge are
the Santa Ritas; the field station is in the valley at the lower right
of the white boundary line).
(return to
main desert ecology class page)
| A view of the experimental range from pine
and douglas-fir forest on the Florida Saddle Trail, looking north
towards Tucson and the Santa Catalinas. |
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| Florida Canyon field station (our white van
is parked in front of our bunk-house. The horse-shoe pits are
just in front.) |
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| Researcher Dr. Dean Martens discussing
studies of soil metabolism and the effects of cattle grazing and
mesquite expansion (trees in phot are mesquite). |
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| An experimental 'exclosure' to assess the
effects of cattle grazing. Ungrazed area (to left) has more diverse
vegetation, different soil structure. |
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| University of Arizona graduate students
explaining experimental studies of the effects of an exotic grass (Eragrostis lehmannii) on native
species. |
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| Megan and Avi studying insect communities
associated with extra-floral nectaries of barrell cactus (Ferocactus wislizinii) |
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| Close-up showing the nectaries (the
reddish-brown spots at base of spines)., |
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| Rachel conducting study of size and habitat
effects on flowering in agave (Agave
deserti). Agaves, or 'century plants' accumulate reserves
for many years (not a century, though) before blooming. Then they
rapidly produce a huge flower stalk and thousands of flowers, after
which they die. |
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| A 'box canyon'. This small stream, in
periodic floods, has carved a steep 'stair-step' canyon. The
shaded pools remain into dry periods, and are sources of water for
wildlife -- but the steep, up-stream walls can be traps. |
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| Blue oak (Quercus
oblongifolia) woodlands on lower slopes of Santa Rita Mts., with
yuccas and prickly-pears. |
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| Pine and douglas-fir forest at higher
elevations in the Santa Ritas. |
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| Yucca (Y. schottii) among pines at about
2500 m elevation |
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| Snow at summits of Santa Ritas. |
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| A July 2005 fire
burned 23,000 acres in the Santa Ritas (red). This view is from the
north; Florida Canyon is the narrow unburned 'neck' lower center.
We will examine effects next time. |
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to
main desert ecology class page)