Details - CALS Networking Lab - University of Arizona

Chapter 3: Plant Inventory
Brian F. Powell
Previous and Ongoing Research
Floras and Plant Collections
We located specimens representing 883 species at
the University of Arizona Herbarium (Appendix
A). Many of these specimens were collected
or reported in Bowers and McLaughlin (1987).
Their treatise is the most comprehensive
annotated flora for the Rincon Mountains, though
species have been added to the list since its
publication. Bowers and McLaughlin (1987)
also provide an excellent overview of previous
research and collecting from the range (as does
Bowers [1984]), the plant communities present,
species richness gradients, and a list of species
extirpated from the range. The Bowers and
McLaughlin list was compiled from work by
Bowers (1984) above 4,500 feet elevation and by
Carole Jenkins who collected from 1978 to 1982
below 4,500 feet elevation. Jenkins never wrote
up the results of her work. The list was updated
in 1996 to include the addition of 34 species
and the subtraction of four (due to incorrect
identifications; Fishbein and Bowers 1996).
There have been floras for four designated natural
areas of the district: Wildhorse Canyon (Rondeau
and Van Devender 1992), Chimenea Canyon
(Fishbein et al. 1994a), Box Canyon (Fishbein
et al. 1994b), and Madrona Canyon (Fishbein
1995). Halvorson and Gebow (2000) compiled
these works into a single volume. Halvorson and
Guertin (2003) mapped locations of 27 species of
non-native plants.
Monitoring, Research, and Single-species Studies
Park personnel established long-term monitoring
plots in low-elevation areas of both units
(Saguaro NP 2005). They used the pointintercept
method at 25 plots in the Rincon
Mountain District and 20 plots in the Tucson
Mountain District and surveyed these transects
from 1998 to 2004 (Mark Holden, pers.
comm.). Funicelli et al. (2001) resurveyed 25,
15
10 x 10 m vegetation plots (established 10 years
prior to their surveys) and mapped each plant
species. These plots were also used by Turner
and Funicelli (2000) to resurvey the condition
and population structure of the saguaro cactus.
Swann et al. (2003a) used the same protocol as
that used by Funicelli et al. (2001) to survey for
plants on the east slope of the Rincon Mountains.
Anderson (2001b) surveyed vegetation transects
at random sites in the Rocking K and adjacent
expansion areas.
The saguaro cactus, the park’s namesake
species, has been one of the most investigated
non-agricultural plants in the world. McAuliffe
(1993) provided an overview of saguaro research
at the park as well as its political and scientific
context. Schwalbe et al. (1999) surveyed
vegetation in and adjacent to the area burned
by the Mother’s Day fire of 1994. Baisan and
Swetnam (1990) constructed a fire history (1657–
1893) of the conifer forest in the vicinity of Mica
Mountain. Though there is a GIS layer of 15
dominant vegetation communities in the district,
there is not a current, detailed vegetation map.
In fact, the most current vegetation map was by
Roseberry and Dole (1939).
Current projects include a fire-effects
monitoring program in the high elevation areas
of the district (Saguaro NP, unpubl. data) and a
program to map and remove non-native species
(e.g., buffelgrass, fountaingrass, Saharan mustard,
and Malta starthistle) from low-elevation areas of
both districts of the park.
Methods
We used three field methods to survey for
vascular plants. General botanizing surveys
involved opportunistically collecting what we
thought might be new additions to the district’s
flora or plants that we could not identify in the
field. We also used modified-Whittaker plots
and point-intercept transects to make quantitative
comparisons among areas and provide data for
long-term monitoring.