PARENT SESSION
Contributed Oral Session 37: Floodplain Restoration
Tuesday, August 9, 8:00 AM - 11:30 AM, Meeting Room 513 A, Level 5, Palais des congrès de Montréal
Resistance and resilience of vernal pool vegetation.
Solomeshch, Ayzik1, Barbour, Michael*,1, Buck, Jennifer1, Starr, Sandra1, Witham, Carol, Macdonald, Roderock, 1 Department of Plant Sciences, University of California, Davis, Davis, CA, USA
ABSTRACT- Extensive development in California has resulted in a significant (70-90%) loss of vernal pool habitats (Holland, 2004), which is one of the few in low elevation California that remains dominated by native plant taxa, including 100 endemics. Vernal pool vegetation is well known as very complex and variable along temporal and spatial gradients. Ecologic-floristic classification has been shown to be a useful operational tool for describing vernal pool vegetation, and development of their management and conservation strategies (Barbour et al., 2003, 2005). But because of high complexity of vernal pool vegetation, its resistance to temporal variation of the environment, and ability to reestablish after disturbance are still not completely understood. This study addresses following questions: (1) How changes of floristic composition of vernal pool communities that occur during one growing season affect results of their classification; (2) How changes that occur from year affect their classification; and (3) Is it possible to create communities that are similar to those that occur in natural vernal pools? To answer first two questions floristic changes on permanent plots were observed and analyzed from April to August during one growing season, and during five consecutive years respectively. Our results show that although species abundance significantly fluctuates over time, their presence/absence remains more or less stable characteristic that allows classification to be consistent. Comparison of floristic composition of 39 natural pools and 35 nine-year old constructed pools at Wurlitzer Preserve (near Chico, CA) showed no significant differences between them, which means that pool construction was quite successful. These results though should not be extrapolated to other situations, because at Wurlitzer reconstruction project did not create an artificial impermeable layer that is crucial characteristic of vernal pool habitat, but rather utilized the existing duripan. Additionally, constructed pools were surrounded by natural pools and grasslands that provided habitats for specialized pollinators necessary for maintenance of vernal pool flora.
Key words: ephemeral wetlands, temporal variation, classification stability, vegetation restoration