The BNZ LTER maintains an extensive program for monitoring climatic, biotic, and physical processes at long-term research sites across Interior Alaska (Table 1). Many of these data sets predate the establishment of the BNZ LTER in 1987. All data are archived online and can be retrieved through the BNZ Data Catalog. We also publish our data to larger repositories, most notably the Environmental Data Initiative (EDI). This monitoring program is the responsibility of the Site Management Team, led by Jamie Hollingsworth (Site Manager) and Karl Olson (Lead Technician), but individual PIs and the Information Manager work closely with this team.

Data are collected at sites within the Bonanza Creek Experimental Forest (BCEF), the Caribou-Poker Creek Research Watershed (CPCRW), the Regional Site Network (RSN), the Eight Mile Lake area (EML), and at long-term experiments such as the Alaska Peatland Experiment (APEX). Detailed information are provided online for these BNZ Research Areas, as are locations/interactive maps of individual BNZ Study Sites. Hundreds of other locations throughout Interior Alaska have been and are being monitored for numerous other parameters, and are described within individual data files.

A brief overview of the main components of the monitoring program are listed below (Table 1), while detailed methods can be found within the metadata descriptions listed for individual data sets.

Table 1. Parameters measured by BNZ LTER monitoring program.

¹Jamie Hollingsworth (site manager) and Karl Olson (technician) are responsible for the climate monitoring program

²Monitoring network includes sites throughout interior Alaska

*Several parameters have been monitored periodically

Climate: BNZ LTER maintains Level 1 climate stations within BCEF and CPCRW that stream real-time climate data. In addition, Level 2 climate stations are maintained at BCEF research sites as is an National Atmospheric Deposition Program (NADP) monitoring station at CPCRW. Current and historical climate data for all of these sites can be visualized and downloaded through the interactive BNZ Meteorological Data Vision Network portal.

Permafrost: Annual thaw depths are measured at the time of maximum thaw at all long-term vegetation sites that have permafrost and several sites within the region where thaw depth monitoring began in the early 1970s. Thaw depth and permafrost temperatures have been monitored in snow addition experiments at EML since the early 2000s. We also collaborate with the UAF Geophysical Institute Permafrost Laboratory, who maintains a network of sites where permafrost temperatures up to 75 m in depth are continuously monitored.

Vegetation and ANPP: Long-term changes in vascular and non-vascular species composition are monitored within one plot at all sites in the BCEF, CPCRW and RSN. Each plot is gridded into subplots, with the interior subplots used for monitoring trees and understory species cover and structure. Tree bands are maintained on a subset of dominant species. Shrubs and tree seedlings/saplings are monitored along the outside edge of the main plot. Litterfall mass by species and seedfall (including counts and germination rates) are also measured. All vegetation data are online, and the protocol, layout, and numbering system for these long-term vegetation plots can be found here in the Research Site Installation Methods. Full vegetation inventories are conducted every 3-10 years depending on stand age.

Insects and Pathogens: Aspen foliar herbivory and densities of the aspen leaf miner (Phyllocnistis populiella) are surveyed annually at BNZ LTER and multiple additional sites near Fairbanks. Foliar herbivory of willow species is monitored annually as part of an experiment established in 2012 along the Tanana River. We established a network of sites for monitoring a fungal stem canker (Valsa melanodiscus) and thin-leaf alder (Alnus tenuifolia) in 2005 in Fairbanks, Eagle River, and on the Kenai Peninsula. In 2015, we initiated a monitoring program of a fungal stem canker in aspen, with 88 sites scattered across eight ecoregions of Interior Alaska.

Snowshoe Hares: Snowshoe hare population abundance and density are being measured twice a year: in May-June and August-September. Population estimates are monitored in conjunction with others made by federal agencies based on pellet and road counts elsewhere in the state (Tetlin NWR, Denali NPP, Gates of the Arctic NPP). BNZ investigators are also monitoring movements of ~70 GPS-collared lynx across the state in collaboration with the Fish & Wildlife Service and the National Park Service.

Stream Discharge and Chemistry: Stream discharge is measured in three streams of the CPCRW. Parshall flumes were installed in sub-catchments in 1977, 1978, or 1979, with stage measurements recorded at regular intervals from 15-60 minutes. Flow rate through flumes is determined by regular manual measurements of stream discharge and the development of rating curves, which are used to generate a continuous discharge record. Stream water is collected daily from five sub-catchments using autosamplers. These samples are collected biweekly, at which time a grab sample is obtained to compare point estimates of stream water chemistry to autosampler data.