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openCC0Feb 2026View details →

Desert Fertilization Experiment: investigation of Sonoran desert ecosystem response to atmospheric deposition and experimental nutrient addition, ongoing since 2006

Launched in 2006 with support from the National Science Foundation (NSF) and leveraged by the CAP LTER, the Carbon and Nitrogen deposition (CNdep) project sought to answer the fundamental question of whether elemental cycles in urban ecosystems are qualitatively different from those in non-urban ecosystems. Ecosystem scientists, atmospheric chemists, and biogeochemists tested the hypothesis that distinct biogeochemical pathways result from elevated inorganic nitrogen and organic carbon deposition from the atmosphere to the land. To test the hypothesis, scientists examined the responsiveness of Sonoran desert ecosystems to nutrient enrichment by capitalizing on a gradient of atmospheric deposition in and around the greater Phoenix metropolitan area. Fifteen desert study sites were established, with five locations each west and east of the urban core, and in the urban core in desert preserves. In addition to the gradient of atmospheric deposition in and around the urban core, select study plots at each of the fifteen desert locations receive amendments of nitrogen, phosphorus, or nitrogen + phosphorus fertilizer. Measured variables include soil properties, perennial and annual plant growth, and atmospheric deposition of nitrogen. At the close of the initial grant period, the CAP LTER assumed responsibility for the project, renamed the Desert Fertilization Experiment, which provides a remarkable platform to study the long-term effects of nutrient enrichment on desert ecosystem properties.

Ants and Ecosystem Function in Hemlock Removal Experiment at Harvard Forest 2006-2014

Eastern hemlock (Tsuga canadensis) is a foundation species in eastern North American forests. Hemlock stands host unique assemblages of flora and fauna, and the structure of these assemblages is expected to change as hemlock declines due to infestation by the hemlock woolly adelgid (Adelges tsugae) and is removed by pre-emptive salvage logging. A 2003 survey of hemlock stands in central Connecticut and Massachusetts showed that ant species richness and abundance is substantially greater in logged and adelgid-infested hemlock stands than it is in intact hemlock stands (see HF065) and we hypothesized that we would see similar changes in ant species diversity following application of treatments in the Hemlock Removal Experiment at the Simes Tract (see HF118). We further hypothesized that because ants are known to modulate ecosystem function in other habitats that observed changes in ant species diversity would be accompanied by changes in ecosystem processes including soil respiration rate and nitrogen availability. In April 2006, we established a set of sub-plots in all eight canopy manipulation plots of the Hemlock Removal Experiment. In each canopy manipulation plot, we installed two ant exclosure plots, two disturbance control plots, and two control plots. Ant species richness and abundance, as well as effectiveness of the exclosures, is monitored with pitfall traps monthly during the summer. Soil nitrogen availability is measured using resins that are collected every three months, and soil respiration is measured bi-weekly during the growing season.

Harvard Forest Summer Research Program in Ecology URSSA Survey since 2006

Program Context Since its inception in 1985, when a single undergraduate worked on a study of old-growth forests, the Harvard Forest Summer Research Program in Ecology (HF-SRPE) has developed into a thriving and well-coordinated program that is central to the educational and research mission of the biological field station. With core support since 1993 from a succession of NSF REU Site awards and NSF REU supplements, and with additional funding from Harvard University, HF-SRPE has grown to support 20-30 undergraduate students annually. Students are mentored by principle investigators and senior scientists in conducting research in ecology, soil science, paleoecology, wildlife biology, conservation biology, and atmospheric sciences. The research conducted by our HF-SRPE students contributes substantially to long-term scientific investigations supported by NSF’s Long-Term Ecological Research (LTER) and National Ecological Observatory Network (NEON), NASA Earth System Science Pathfinder (ESSP) – Earth Ventures (EV) programs, The Smithsonian Institution’s ForestGEO network of plots, and Department of Energy’s (DOE) National Institute for Global Environmental Change (NIGEC). The overarching objectives of the program are to: enhance the ability of students to undertake high-quality interdisciplinary research; build teams of researchers in which students bring different strengths to the table, collaborate on cutting-edge projects, and find their own intellectual “voice”; encourage students to link fundamental and applied issues in their research; and cultivate the next generation of ecological scientists and educators that reflects the diversity of backgrounds and experiences of students in the United States. Problem Statement Starting in 2005 the National Science Foundation (NSF), as one of the largest funders of undergraduate research programs, began emphasizing the use of project evaluations to both qualitatively and quantitatively measure the success of REU programs (R

Incidence of Ticks and Tick Bites at Harvard Forest since 2006

In an effort to determine exposure to ticks and to determine appropriate preventative measures to reduce the occurrence of Lyme Disease in summer research interns at Harvard Forest, data are collected about where students work at Harvard Forest; the time spent in the field; the number of ticks students find on themselves after each trip to the field; and the number of ticks that actually bite and embed themselves in the skin. From these data, we estimate areas of high tick densities and estimate time of summer during which ticks are most prevalent. The results are used to develop recommendations for appropriate precautions that students can take to avoid tick-borne diseases.

openCC0Sep 2021View details →

Desert Fertilization Experiment: investigation of Sonoran desert ecosystem response to atmospheric deposition and experimental nutrient addition, ongoing since 2006 (Reformatted to the ecocomDP Design Pattern)

This data package is formatted as an ecocomDP (Ecological Community Data Pattern). For more information on ecocomDP see https://github.com/EDIorg/ecocomDP. This Level 1 data package was derived from the Level 0 data package found here: https://pasta.lternet.edu/package/metadata/eml/knb-lter-cap/632/9. The abstract below was extracted from the Level 0 data package and is included for context:

Water Quality Data (Grab Samples) from the Taylor Slough, just outside Everglades National Park (FCE), for August 1998 to November 2006

Water quality samples are being collected using ISCO autosamplers at all wetland sites (that is, all sites except TS/Ph-9, 10, and 11). The autosamplers contain 24 1L bottles. Water is sampled by programming the autosamplers to take composite samples once every 3 days. These samples are a composite of four 250mL subsamples drawn every 18 hours (a sampling scheme that captures a dawn, noon, dusk, and midnight sample in every three day composite). The samples are collected every 3-4 weeks and analyzed for total phosphorus (TP), total nitrogen (TN), and salinity. When sites are visited to collect these samples, we also collect a grab sample that is immediately put on ice. A portion of these grab samples is filtered through a Whatman GF/F filter immediately upon return to the lab, and the filtered samples are analyzed for inorganic nutrients such as NO2-, NO3-, NH4+, SRP, and DOC. The unfiltered fraction of these grab samples is analyzed for TP, TN, and TOC. We use these montly grab samples to generate relationships between TP and SRP, and between TN and NO2- + NO3- + NH4+. Dissolved nutrients are measured using standard rapid flow analyzer (RFA) techniques. TP is analyzed with a modified Solorzano and Sharp (1980) technique. TN is measured with an Antec TN analyzer, TOC and DOC are quantified on a Shimadzu TOC Analyzer, and salinity is measured with a YSI conductivity meter. In addition to the regular water quality monitoring, we use the rain level actuators at all freshwater sites to trigger water sampling after rain events exceed a given threshold of duration and/or intensity. As currently programmed, when the threshold of = 2.5 cm of rain per hour is passed, the autosampler at that site collects a 1L sample every 15 minutes after the threshold has been reached and remains (previous to 2003- the autosampler was programmed to collect 500mL of water every 30 minutes while the threshold was being met). Rain event samples are collected, retrieved, and analyzed like out c

Soil Physical Data from the Taylor Slough, just outside Everglades National Park (FCE), from October 1998 to October 2006

Soil pH, Eh and temperature readings are taken at TS/Ph4 and TS/Ph5. These measurements are taken only when the marsh is wet. Measurements are taken using an Orion model 250A meter, and the probes attached to the meter are the Orion Thermo pH probe and the Orion Eh probe. All readings are recorded in field notebooks, and then transferred into Microsoft Excel. The Eh reading is taken when the Eh probe is attached to the meter and the word "Ready" appears on the meter screen. The pH and temperature reading are taken when the pH probe is attached to the meter and the word "Ready" appears on the meter screen.

Soil Physical Data from the Taylor Slough, within Everglades National Park (FCE), from September 1999 to November 2006

Soil pH, Eh and temperature readings are taken at TS/Ph1b,TS/Ph2,TS/Ph3 and TS/Ph6b. These measurements are taken only when the marsh is wet. Measurements are taken using an Orion model 250A meter, and the probes attached to the meter are the Orion Thermo pH probe and the Orion Eh probe. All readings are recorded in field notebooks, and then transferred into Microsoft Excel. The Eh reading is taken when the Eh probe is attached to the meter and the word "Ready" appears on the meter screen. The pH and temperature reading are taken when the pH probe is attached to the meter and the word "Ready" appears on the meter screen.

Ant Diversity and Vegetation Composition in Hemlock Removal Experiment at Harvard Forest 2006

Ants comprise a considerable amount of animal biomass in terrestrial ecosystems and play major roles in ecological processes ranging from seed dispersal to soil turnover. Invasion by the hemlock woolly adelgid will transform late-successional hemlock forests into earlier successional mixed hardwood-white pine forests or red-maple wetlands. Understanding how ant assemblages vary in different habitat types allows for predictions of how hemlock decline could alter the composition of ant assemblages, with implications for a wide range of ecosystem processes. An ongoing study at the Simes Tract of Harvard Forest is documenting the effects of invasion and land-use history on ant biodiversity. Surveys from 2003 to 2005 focused on ant structure in hemlock and hardwood microhabitats in the Harvard Forest Hemlock Removal Experiment, in which hemlock forest response to deforestation by the hemlock woolly adelgid (Adelges tsugae) and to selective logging is being examined (Ellison et al. 2005). In the summer of 2006, we surveyed a greater range of microhabitat types with two objectives. First, to collect rare or elusive species in hemlock and hardwood stands that may have gone uncollected in previous years. Second, to sample forest communities not included in previous years - white pine, swamp, and rocky slope - for ant species unique to these microhabitats. We found fourteen newly documented species of ants in the Simes Tract - nine of which were in an open, swamp. Aphaenogaster rudis and Camponotus pennsylvanicus were the only ant species found in all microhabitat types. In a canonical correspondence analysis, A. rudis and C. pennsylvanicus were associated most strongly with hemlock stands and low species richness of understory plants.

Regional and Historical Variation in Garlic Mustard Distribution in Western Massachusetts 2006-2007

The susceptibility of a site to invasion by nonnative species depends on its current ecological features and its historical land use. Certain environments might be more conducive to an invasive plant’s success, and several recent studies have shown that former agricultural sites are more susceptible to invasion than sites that have been continuously wooded. We studied the invasive herb garlic mustard (Alliaria petiolata), at roadside forested edges. Site selection was stratified by two regions with distinct ecological characteristics (the Connecticut River Valley and the Berkshire Valley in Massachusetts), and two historical land uses (wooded versus cleared in 1830).

Harvard Forest Summer Research Program in Ecology Pre/Post Survey 2006-2015

Natural Land Zones in New England in 2006 from 2010 Wildlands and Woodlands Report

This GIS dataset shows different Wildland and Woodland zones in New England and is intended to illustrate how the percentage of protected land could vary between New England landscapes while achieving the total acreage goals as expressed in the Wildlands and Woodlands 2010 Report. This is layer is intended to be conceptual and not prescriptive. The zones were created by expressing the percent natural landcover for a given 500m pixel using a 25 x 25-cell neighborhood. The landuse categories considered to be natural and the breakpoints for each zone are given in the Methods section of this document. The data are provided in vector format as an ESRI shapefile. The projection is NAD 1983 Albers. The Wildlands and Woodlands webpage, http://www.wildlandsandwoodlands.org/, includes a downloadable high-resolution copy of the report and an extensive set of resources that complement and support the arguments and facts presented in it. These include citations, metadata, and downloadable high-quality images of all the graphs and maps. The website will be updated to provide further information on many of the findings, activities, and recommendations provided in the report. Wildlands and Woodlands Report: Foster, D. R., Lambert, K. F., Kittredge, D. B., Donahue, B. M, Hart, C. M., Labich, W. G., Meyer, S., Thompson, J. , Buchanan, M., Levitt, J. N., Pershel, R., Ross, K., Elkins, G., Daigle, C., Hall, B., Faison, E. K., D'Amato, A. W., Forman, R. T. T., Del Tredici, P., Irland, L. C., Colburn, B. A., Orwig, D. A., Aber, J. D., Berger, A., Driscoll, C. T., Keeton, W. S., Lilieholm, R. J., Pederson, N., Ellison, A. M., Hunter, M. L., Fahey, T. J. 2017. Wildlands and Woodlands, Farmlands and Communities: Broadening the Vision for New England.

Carbon Biogeochemistry of Forested Headwater Streams at Harvard Forest 2006-2007

Headwater streams make up greater than 80% of total channel length in the United States and play important roles in regulating nutrient, organic matter, and sediment fluxes from terrestrial to downstream ecosystems. Headwater streams are common features of many upland-forested watersheds in New England, yet are not explicitly factored into forest water, carbon, and nutrient budgets. Here we report on recent efforts to examine terrestrial and stream ecosystem linkages in carbon biogeochemistry in a hemlock-dominated watershed. A prototype stream biogeochemical system (SBS) was tested at the Harvard Forest LTER. The SBS allows a suite of stream water properties to be characterized in real-time over extended periods of time thus allowing questions to be asked at a wide range of time scales. The prototype SBS was field-tested in Bigelow Brook West on the Prospect Hill research tract at Harvard Forest. Bigelow Brook West was selected because the watershed’s hydrology, stream ecology, forest composition, land-use history, and carbon sequestration have been characterized, thus aiding the interpretation of SBS data and facilitating multi-disciplinary research. The prototype system monitors stream and air temperature, pCO2 , colored dissolved organic matter, total suspended sediments, PAR, water depth, pH, and dissolved O2. Independent estimates of organic and inorganic water chemistry were used to validate and interpret SBS data. Here we report on preliminary findings from the pilot SBS at Harvard Forest to highlight the usefulness of headwater stream chemistry data to a wide-diversity of ecosystem scientists. 1) Low pH constrains dissolved inorganic carbon solute fluxes to downstream ecosystems. 2) CO2 concentrations were always supersaturated in Bigelow Brook, averaging about 6x atmospheric values in summer, thus the stream is an important source of CO2 to the atmosphere. Variation in CO2 appears to be linked to multiple mechanisms including changes in stream temperature,

openCC0Jan 2026View details →

Soil Warming Plus Nitrogen Addition Experiment at Harvard Forest since 2006

Climate warming and N deposition are occurring on a global scale with unknown long-term effects on soil microbial communities and the biogeochemical processes they perform. Few studies have examined the interactive effects of elevated temperatures and N additions on soil microbial community structure and function. The overall objective of this study is to investigate whether warming and N additions restructure microbial communities and alter the response of soil C pools to these two stressors. A related study is examining the interactive effects of warming and N additions on plant and ant diversity. This research is being carried out at the Soil Warming x Nitrogen Addition Study at the Harvard Forest which includes four treatments: control, warming (heating to 5 deg C above ambient), warming x N, and N additions only (addition of 50 kg N/ha/yr). Soil respiration measurements have been made monthly since the beginning of the experiment in 2006. In 2010 and 2011, two different methods were compared: static chamber measurements and instantaneous field IRGA assessments. Soil samples (~0-10 cm) have been sampled annually for total C and N, N mineralization, and microbial community composition. Most recently, soils were collected in October 2011 from across the entire profile (0-50 cm) to access potential changes in soil C and N pools with depth. First, 20 x 20 cm forest floor samples were collected. Mineral soils were then collected in 10 cm depth increments to ~50 cm. Samples are currently being analyzed for total C and N, microbial biomass and community composition and fungal gene expression (transcriptomics). Additionally, long-term incubations are being conducted to measure labile and recalcitrant C fractions. Additional soil physical (texture) and chemical (pH, inorganic N) are being measured. Field season measurements of soil respiration indicate that both warming and N additions continue to stimulate CO2 flux, with warming treatments having a stronger effect on re

Inventory of Ants at the Black Rock Forest in Cornwall NY 2006-2015

Ants are key indicators of ecological change, but few studies have investigated how ant assemblages may respond to dramatic changes in vegetation structure in temperate forests. Pests and pathogens are causing widespread loss of dominant canopy tree species; ant species composition and abundance may be very sensitive to such losses. Prior to the experimental removal of red oak trees to simulate effects of sudden oak death and examine the long-term impact of oak loss at the Black Rock Forest (Cornwall, New York), we carried out a rapid assessment of the ant assemblage in the 10-hectare experimental area. We also determined the efficacy in a northern temperate forest of five different collecting methods - pitfall traps, litter samples, tuna-fish and cookie baits, and hand collection - routinely used to sample ants in tropical systems. A total of 33 species in 14 genera were collected and identified; the myrmecines Aphaenogaster rudis and Myrmica punctiventris, and the formicine Formica neogagates were the most common and abundant species encountered. Ninety-four percent (31 of 33) of the species were collected by litter sampling and structured hand sampling together, and we conclude that in combination, these two methods are sufficient to assess species richness and composition of ant assemblages in northern temperate forests. Using new, unbiased estimators, we project that 38-58 ant species are likely to occur at Black Rock Forest. Loss of oak from these forests may favor Camponotus species that nest in decomposing wood and open-habitat specialists in the genus Lasius.

Stream Periphyton Response to Hemlock Mortality in Central Massachusetts 2006

The Hemlock Wooly Adelgid (HWA) invasion is expected to cause widespread mortality of eastern hemlock [Tsuga canadensis (L.) Carriere] throughout much of New England. Light levels in streams with hemlock riparian zones are anticipated to increase as hemlock are replaced by deciduous trees. We sought to: 1) quantify differences in light reaching streams with hemlock and deciduous riparian zones, 2) determine if increases in light result in higher periphyton biomass, and 3) explore the role of macroinvertebrate grazing on periphyton biomass as light increases in an attempt to help predict stream ecosystem responses to hemlock mortality. Light measurements were taken along 100-800m stream reaches with riparian zones of healthy hemlock and deciduous trees in MA and CT in order to document an integrated light profile for each stream. In addition, a 2 x 2 factorial experimental design with five replicates was executed on a deciduous reach of Egypt Brook in central MA, in which light (high light vs. low light) and grazing (high grazing vs. low grazing) were manipulated. Light measurements were significantly higher for streams with deciduous riparian zones than hemlock riparian zones. Controlled shading reduced chlorophyll a, while excluding grazing yielded inconclusive results. Periphyton biomass in Egypt Brook was found to be light limited, and grazing did not suppress periphyton biomass. As hemlocks die, in-stream light will be significantly augmented, and periphyton biomass will increase. A challenge for stream ecologists will be to incorporate multiple physical, chemical, and biological controls on biota in order to fully understand how regional hemlock mortality will alter stream periphyton biomass.

openCC (other)Dec 2022View details →

Lake Mendota Microbial Observatory Temperature, Dissolved Oxygen, pH, and conductivity data, 2006-present.

The Lake Mendota Microbial Observatory collects routine water physical and chemical measurements alongside their microbial samples. This dataset includes measurements of water temperature, dissolved oxygen, pH, and conductivity collected at the central Deep Hole, collocated with a weather buoy (43°05'58.2"N 89°24'16.2"W). All measurements were collected with handheld probes. Data from 2006-2014 was compiled from multiple sources and includes only water temperature and dissolved oxygen. Data from 2014-2019 is from the same probe, a YSI Pro Plus instrument, and also includes pH and specific conductance. Routine microbial observatory sampling continues into the present.

Increased temperature, N and snowpack experiment for north of saddle, 2006 - ongoing.

In 2006 we established a global change experiment in the Front Range of the Rocky Mountains to investigate how manipulations of warmer summer temperature, N deposition, and increased snowpack would affect the growth of alpine plants. The experiment was implemented on Niwot Ridge, where shrub cover has expanded by over 400% since 1946 (Formica et al. 2014). We established experimental plots north of the Niwot Ridge saddle, in an area of moist meadow tundra where willow shrub (Salix sp.) patches are present. Within experimental plots, Salix glauca seedlings were transplanted in 2006 and 2007 to test whether changing environmental conditions facilitated shrub survival and growth. In 2007 and 2008, phenological observations were recorded for all (2007) or abundant (2008) species in experimental plots. Measurements of plant species composition and aboveground net primary productivity (ANPP) are also made annually or biennially (ANPP, 2017-onward). In 2021, canopy height and NDVI began being measured annually. In July of 2016, a community transplant experiment was implemented to test whether changing environmental conditions support changes in alpine tundra plant communities. Two species characteristic of (1) dry meadow tundra (Tetraneuris acaulis, Erigeron pinnatisectus), (2) snowbed tundra (Ranunculus adoneus, Saxifraga rhomboidea) and (3) subalpine meadow (Trollius albiflorus, Polemonium pulcherrimum) were transplanted into experimental plots. Survival and growth of transplants was documented annually through 2021.