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Dataset Abstract This dataset includes total carbon and total nitrogen measured for plants from the LTER Main Site and the Successional and Forested sites. Total C and N are analyzed at peak biomass for a given treatment. In some systems with multiple harvests or complex communities that have peaks occurring at different times of the year, measurements are taken at multiple times per year. Samples are combusted and measured on a CHN analyzer. original data source http://lter.kbs.msu.edu/datasets/32
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Annual Net Primary Production on the Main Cropping System Experiment at the Kellogg Biological Station, Hickory Corners, MI (1990 to 2018)
Dataset Abstract Aboveground annual net primary production (ANPP) has been measured on the LTER main site since 1990 and on the successional and forested sites since 1993. ANPP is measured at peak biomass for a given treatment. In some systems with multiple harvests or complex communities that have peaks occurring at different times of the year, measurements are taken at multiple times per year. Additional ANPP measurements are made where appropriate using leaf litter traps, estimates of diameter from tree basal diameter and for the poplar treatment occasional destructive harvests. See the ANPP protocol for descriptions of the sampling and measurement methods for each of the treatments. original data source http://lter.kbs.msu.edu/datasets/22
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- Award ID(s):
- 1832042
- PAR ID:
- 10357098
- Publisher / Repository:
- Environmental Data Initiative
- Date Published:
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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{"Abstract":["In 2003, the U.S. Fish and Wildlife Service conducted a prescribed\n burn over a large part of the northeastern corner of the Sevilleta\n NWR. This study was designed to look at the effect of fire on\n above-ground net primary productivity (ANPP) within different\n vegetation types. Net primary production (NPP) is a fundamental\n ecological variable that measures rates of carbon consumption and\n fixation. Estimates of NPP are important in understanding energy\n flow at a community level as well as spatial and temporal responses\n to a range of ecological processes. While measures of both below-\n and above-ground biomass are important in estimating total NPP, this\n study focuses on above-ground net primary production (ANPP).\n Above-ground net primary production (ANPP) is equal to the change in\n plant mass, including loss to death and decomposition, over a given\n period of time. To measure this change, ANPP is sampled twice a year\n (spring and fall) for all species in each of three vegetation types.\n In addition, volumetric measurements are obtained from adjacent\n areas to build regressions correlating biomass and volume. Three\n vegetation types were chosen for this study: mixed grass (MG), mixed\n shrub (MS) and black grama (G). Forty permanent 1m x 1m plots were\n installed in both burned and unburned sections of each habitat type.\n The core black grama site included in SEV129 was incorporated into\n this dataset as an unburned control, so an additional unburned G\n site was not created. The data for this site is noted as site=G and\n treatment=C (i.e., control). The original mixed-grass unburned plot\n caught fire unexpectedly in the fall of 2009 and was subsequently\n moved to the south. Volumetric measurements are made using\n vegetation data from permanent plots collected in SEV156, "Burn\n Study Sites Quadrat Data for the Net Primary Production Study"\n and regressions correlating biomass and volume constructed using\n seasonal harvest weights from SEV157, "Net Primary Productivity\n (NPP) Weight Data.""]}more » « less
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We measured light‐related patterns of primary productivity within a topographically complex Oregon watershed over a 30‐year period. Second‐growth conifer densities were experimentally altered in 1981. Plots receiving at least 3434 MJ m−2over a 6‐month growing season averaged 40% greater aboveground net primary productivity (ANPP) than those receiving less light (p = 0.000). Unthinned stands potentially built enough LAI to compensate for low light, but risked mortality that exceeded resilience. The two light levels acted as basins of attraction for other physiological and ecological processes, including size–density relationships and limiting foliar nutrients. Initial (1981) LAI and the irradiation step (above or below 3434 MJ m−2) explained 60% of variation in a 30‐year ANPP. Irradiation within each light group did not affect ANPP. At high irradiation, foliar N/Ca and slope steepness (both negative) explained 58% of the variation in residuals from the initial models, while at low irradiation on north, east, and west aspects, 83% of residual variation was explained by foliar Mg (+), understory cover (+), and 30‐year mortality (−). Light use efficiency (LUE) of fully stocked stands correlated with LAI and foliar N/K. Results suggest that understory influence on tree foliar N (+ or −) enhances ANPP by regulating critical nutrient ratios. Mortality reduced or eliminated differences among thinning levels, which did not vary at low light and only between unthinned and heavily thinned at high light. Values associated with relatively open forests (biodiversity, resilience) may be attained without large sacrifice of long‐term carbon sinks. In our study, light interacts with topography to produce nonlinear dynamics in which small changes in irradiation can have large consequences. Reduced sunlight has been suggested as a geoengineering option to combat global warming. Ecological changes out of proportion to lowered irradiation are a distinct possibility, including sharp reductions in terrestrial carbon sinks.more » « less
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Abstract Drivers of shrub primary production and associated landscape impacts of encroachment are well known in drylands but have not been thoroughly studied in mesic and coastal habitats. The native, nitrogen-fixing shrub,Morella cerifera,has expanded into coastal grassland along the US Atlantic coast due to warming temperatures, but impacts on ecosystem function are not well known. Annual net primary production (ANPP) ofMorella ceriferaand key environmental drivers were measured long-term (1990 – 2007) across a chronosequence of shrub age on a mid-Atlantic barrier island. Soil and groundwater nutrients were compared with un-encroached grassland soil to evaluate impacts of vegetation on nutrient dynamics. Shrub ANPP declined with age at the same rate among all thickets, but there was variability from year to year. When climate variables were included in models, shrub age, precipitation, and freshwater table depth were consistent predictors of ANPP. Water table depth decreased over time, reducing ANPP. This may be due to rising sea-level, as well as to feedbacks with shrub age and evapotranspiration. Soil N and C increased with shrub age and were higher than adjacent grassland sites; however, there was a significant loss of N and C to groundwater. Our results demonstrate that drivers influencing the encroachment of shrubs in this coastal system (i.e., warming temperature) are not as important in predicting shrub primary production. Rather, interactions between shrub age and hydrological properties impact ANPP, contributing to coastal carbon storage.more » « less
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