Wetlands of Lassen Volcanic National Park - NPS Inventory and ...

Decades of fire suppression also have affected LAVO vegetation because some types of fires are
important in shaping vegetation communities (Taylor 2000). However, intense fires and the use of
heavy equipment and flame retardants used in fire fighting can potentially harm wetlands. Recognizing
the importance of fire as a natural shaper of ecological communities, current policies allow fires that
start naturally in many parts of LAVO to burn with only limited control efforts. NPS staff also conduct
controlled burns in selected areas of the park. Many of LAVO’s montane meadows are wetlands. As a
result of decades of fire suppression, prolonged drought, and/or other factors, many montane meadows
are gradually being invaded by trees, with consequent impacts on herbaceous plants and some wildlife
species (Berlow and D’Antonio 2002). Other natural factors that are likely to have influenced the
occurrence and characteristics of the park’s wetlands and their vegetation include landslides, seismic
and volcanic activity, springs, beaver, insect and plant disease outbreaks, wind storms, and annual
changes in temperature and precipitation (snow amount, date of complete meltdown in each wetland,
occurrence of summer rains, timing and duration of freezing). Global climate change can alter the
frequency and intensity of these natural disturbances, thus posing an increasing threat to the park’s
wetlands and their biological communities.
Although relatively few pollution sources remain within the park, long­distance airborne transport of
contaminants poses a potential threat. A recent study found evidence for nutrient enrichment of high­
elevation lakes in the Sierra Nevada (Sickman et al. 2003), and it has been suggested that the source
might be increased levels of atmospheric nitrogen, phosphorous, and pesticides in dust and soil aerially
transported from the Central Valley of California or Asia. The Western Airborne Contaminants
Assessment Project (Landers et al. 2008) determined that lichens and conifers sampled at five sites in
LAVO were contaminated with several pesticides currently used outside the park, especially
endosulfans and dacthal, but also chropyrifos and g­HCH (lindane) and historically­used DDT,
hexachlorobenzene, chlordanes, dieldrin, and PCB. Lichens and/or conifers also had relatively high
levels of PAHs (combustion by­products). These contaminants were also present in air samples at
levels mostly greater than found in other western parks. Concentrations increased with elevation within
the park. Also present in air samples at above­median concentrations were triuralin (an herbicide) and
the historically­used pesticides chlordane, DDT, HCB, and a­HCH (alpha hexachlorocyclohexane).
Nitrogen deposition was not elevated compared with other western parks. In other parts of the Sierras,
long distance transport of airborne pesticides has been noted (Zabik and Seiber 1993) with possible
damage to amphibian populations (Davidson 2004).
3.3.2 Wetland Health as Indicated by Plants
Biodiversity and Reference Conditions: Through our wetland survey efforts, six species that were
previously unknown in the park have been added to the park’s flora. These are as follows
(parenthesized codes are their wetland indicator status, see Table 11):
• Sisyrinchium elmeri. (OBL). Found at Upper Meadow in the Kings Creek drainage within sight
of the park road (site NR473). Plants were found growing near a seep on the eastern edge of the
meadow in full sun. This population may represent the first documented collection of this plant
in Shasta County, although it has been collected just south of the park in Tehama County.
• Danthonia intermedia. (FACU+). Found at several locations in the park. The absence of this
plant from the park’s flora may be the result of differing classifications; the key in the Lassen
Flora by Gillett et al. results in a different identification from the key in the Jepson Manual
(Hickman 1993).
• Elodea canadensis. (OBL). Found in Manzanita Lake. The nativity of this plant to the park is
unknown. There is a possibility that this plant may have been introduced incidentally by
fishermen, although it is native to the region and has previously been documented at locations
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