In-canopy and in-soil microclimates for the
subalpine Willow Leaf Beetle Chrysomela aeneicollis


Data set 2000-2015
Daily summaries
Annual cycle
Elevation lapse rates
Snow cover
Long term trends

Table 1. List of Willow Leaf Beetle monitoring sites

Introduction Wild populations of the Willow Leaf Beetle Chrysomela aeneicollis have been monitored and subjected to analysis and experimentation since 1981. Summary of the body of work follows...

The goals of this analysis are to provide a description of the microclimate temperature regime experienced by the beetles at each of the study sites, comparing drainages and looking for elevation effects and long-term trends. Additional goals are to examine trends in snow cover as a function of drainage and elevation and to derive the relationship between the microclimate temperatures (as experienced by the beetles) and air temperatures as measured by conventional means. Finally, we summarize a limited subset of relative humidity and solar radiation measurements.

Data set 2000-2015 In June, 2000 we installed several series of temperature loggers in Sierra Nevada drainages corresponding to Chrysomela aeneicollis study sites. The intention of the sampling design was to measure temperatures that would be experienced by beetles feeding on the underside of leaves within the willow canopy. This location is typical for eggs and larvae of the beetles, and on hot days, the adults also. We suspended loggers inside upended plastic cups covered in bright white tape, so that the loggers were exposed to ground radiation only while the cup shielded against sky radiation. Cups were perforated with 1mm diam holes to allow air circulation and prevent heat buildup inside the cup. Cups were suspended inside the canopy of willow shrubs just under the principal canopy leaf layer, the most common location for eggs and larvae. In the first years we used "Tidbit" temperature loggers, programming them to record temperatures every 30 minutes. In summer 2005 we switched over to using "Hobo" pendant loggers, recording at 20 minute or 30 minute intervals.

Willow beetle monitoring and study sites with accompnying temperature loggers were installed in seven drainages along the central eastern Sierra Navada escarpment. This massive range front forms a wall along the western side of North America's deepest valley, with steep altitudinal gradients rising 2000 meters in 10 km. This wall is incised with numerous drainages, opening to the east and north, perpendicular to the orientation of the escarpment. Sites were chosen to represent the elevation gradients in each drainage with 1-200 meter steps between each successive location. To the southeast, Big Pine Creek (9 sites) hosts permanent populations of the southern forms of the Willow Leaf Beetle Chrysomela aeneicollis, and Rock Creek (7 sites) to the northwest hosts northern forms. In between are four subdrainages of Bishop Creek (25 sites) and Pine Creek (4 sites), hosting intermediate populations. Table 1 lists the site names and locations and Figures 1-3 illustrate the site locations on the landscape.

Daily summaries bb Figure 4 illustrates the mean temperatures recorded by the 15 core CUP loggers over the 15-year period.

Annual cycle bb

Elevation lapse rates bb

Snow cover bb

Long term trends bb