Laserfiche WebLink
<br />,(: <br />\.~\);) <br /> <br />13 <br /> <br />, <br /> <br />attributes varied by vegetation type and parameter measured (e,g" species richness, density), For <br />example, changes in cover can be detected within a year's time for mixed scrub, but changes in <br />diversity for the same community type may take over 20 years, Kearsley and Ayers (2001) <br />analysis also indicated that the minimum number of sites needed to detect change in species <br />richness and cover is between 30 and 70, depending on the type of vegetation (Kearsley and <br />Ayers, 2001), and that previous approaches and sites over-represented some types of vegetation <br />(e,g" tamarisk) and under-represented others (e,g" seep willow), Areas of high density, single <br />species composition were more likely to show little change compared to mixed communities and <br />would require longer time periods for change detection, In most cases, change was detectable <br />within five years of measurement. The temporal and spatial scale as well as number of sites <br />needed to detect change was taken into account in the development of core monitoring <br />approaches for terrestrial resources. <br />Currently core monitoring includes yearly field-based assessment of vegetation cover, <br />species richness and diversity at 60 sites that are linked to stage/discharge changes up to 60,000 <br />cfs, and five-year change detection at the landscape scale using GIS and image processing, The <br />basemap of vegetated areas initiated in FY2003 and to be completed in FY2004 serves as a <br />template for past and future large-scale change detection, as well as for randomized selection of <br />monitoring sites for vertebrates including bird patches. Results from the monitoring project for <br />vegetation indicate measures of plant abundance, species richness, diversity, and distribution all <br />showed a decline in 2002 compared to 2001 (Kearsley 2002), data from 2003 is still to be <br />provided, Herbaceous desert annuals and perennial grasses and herbs like cheat grass, sand <br />dropseed and spiny aster showed the greatest decline and are affected by yearly precipitation, <br />Compositional shifts did not occur for zones below 35k cfs, but at sites of 45k and 60 k cfs, <br />species composition did change significantly compared to 2001, again the change is associated <br />more with a loss of annual and rarely encounter plant species, The mean wetland score, which <br />most closely tracks operational effects on vegetation and available groundwater, showed no <br />change within zones between years, but an increase in value for all zones compared to 2001 <br />(Kearsely 2002). As long-term data accumulate we will be better able to see how yearly <br />operations and weather patterns affect vegetation, <br />Monitoring for riparian breeding birds, including southwest willow flycatcher, and over- <br />wintering waterfowl continues, Power analysis by Spence et al. 2003 indicates that <br /> <br />GCMRC FY2005-2006 Draft Annual Work Plan (November 10,2003) <br />