net primary production

Core Site Grid Seasonal Biomass and Seasonal and Annual NPP Data at the Sevilleta National Wildlife Refuge, New Mexico (2013 - present)

Abstract: 

Begun in spring 2013, this project is part of a long-term study at the Sevilleta LTER measuring net primary production (NPP) across three distinct ecosystems: creosote-dominant shrubland (Site C), black grama-dominant grassland (Site G), and blue grama-dominant grassland (Site B). Net primary production is a fundamental ecological variable that quantifies rates of carbon consumption and fixation. Estimates of NPP are important in understanding energy flow at a community level as well as spatial and temporal responses to a range of ecological processes.

Above-ground net primary production is the change in plant biomass, represented by stems, flowers, fruit and and foliage, over time and incoporates growth as well as loss to death and decomposition. To measure this change the vegetation variables in this dataset, including species composition and the cover and height of individuals, are sampled twice yearly (spring and fall) at permanent 1m x 1m plots within each site. A third sampling at Site C is performed in the winter. Volumetric measurements are made using vegetation data from permanent plots (SEV289, "Core Site Grid Quadrat Data for the Net Primary Production Study") and regressions correlating species biomass and volume constructed using seasonal harvest weights from SEV157, "Net Primary Productivity (NPP) Weight Data."

Data set ID: 

291

Core Areas: 

Additional Project roles: 

433
434
435
436

Keywords: 

Methods: 

Data Processing Techniques to Derive Biomass and NPP:

Data from SEV289 and SEV157 are used used to calculate seasonal and annual production of each species in each quadrat for a given year. Allometric equations derived from harvested samples of each species for each season are applied to the measured cover, height, and count of each species in each quadrat. This provides seasonal biomass for winter, spring, and fall.

Seasonal NPP is derived by subtracting the previous season's biomass from the biomass for the current season. For example, spring NPP is calculated by subtracting the winter weight from the spring weight for each species in a given quadrat. Negative differences are considered to be 0. Likewise, fall production is computed by subtracting spring biomass from fall biomass. Annual biomass is taken as the sum of spring and fall NPP.

Data sources: 

sev291_coregridbiomass_20150818

Additional information: 

Other researchers involved with collecting samples/data: Chandra Tucker (CAT; 04/2014-present), Megan McClung (MAM; 04/2013-present), Stephanie Baker (SRB; 2013-present), John Mulhouse (JMM; 2013).

Pinon-Juniper (Core Site) Seasonal Biomass and Seasonal and Annual NPP Data for the Net Primary Production Study at the Sevilleta National Wildlife Refuge, New Mexico (2003-present)

Abstract: 

This dataset contains pinon-juniper woodland biomass data and is part of a long-term study at the Sevilleta LTER measuring net primary production (NPP) across four distinct ecosystems: creosote-dominant shrubland (Site C, est. winter 1999), black grama-dominant grassland (Site G, est. winter 1999), blue grama-dominant grassland (Site B, est. winter 2002), and pinon-juniper woodland (Site P, est. winter 2003). Net primary production is a fundamental ecological variable that quantifies rates of carbon consumption and fixation. Estimates of NPP are important in understanding energy flow at a community level as well as spatial and temporal responses to a range of ecological processes.

Above-ground net primary production is the change in plant biomass, represented by stems, flowers, fruit and and foliage, over time and incoporates growth as well as loss to death and decomposition. To measure this change the vegetation variables in this dataset, including species composition and the cover and height of individuals, are sampled twice yearly (spring and fall) at permanent 1m x 1m plots within each site. A third sampling at Site C is performed in the winter. Volumetric measurements are made using vegetation data from permanent plots (SEV278, "Pinon-Juniper (Core Site) Quadrat Data for the Net Primary Production Study") and regressions correlating species biomass and volume constructed using seasonal harvest weights from SEV157, "Net Primary Productivity (NPP) Weight Data."

Data set ID: 

290

Core Areas: 

Additional Project roles: 

482
483
484
485

Keywords: 

Methods: 

Data Processing Techniques to Derive Biomass and NPP:

Data from SEV278 and SEV157 are used used to calculate seasonal and annual production of each species in each quadrat for a given year. Allometric equations derived from harvested samples of each species for each season are applied to the measured cover, height, and count of each species in each quadrat. This provides seasonal biomass for winter, spring, and fall.

Seasonal NPP is derived by subtracting the previous season's biomass from the biomass for the current season. For example, spring NPP is calculated by subtracting the winter weight from the spring weight for each species in a given quadrat. Negative differences are considered to be 0. Likewise, fall production is computed by subtracting spring biomass from fall biomass. Annual biomass is taken as the sum of spring and fall NPP.

Data sources: 

289_npppinjbiomass_20150824

Additional information: 

Other researchers involved with collecting samples/data: Chandra Tucker (CAT; 04/2014-present),  Megan McClung (MAM; 04/2013-present), Stephanie Baker (SRB; 10/2010-present), John Mulhouse (JMM; 08/2009-06/2013), Amaris Swann (ALS; 08/2008-present), Maya Kapoor (MLK; 08/2003 - 01/2005, 05/2010 - 03/2011), Terri Koontz (TLK; 02/2000 - 08/2003, 08/2006 - 08/2010), Yang Xia (YX; 01/2005 - 03/2010), Karen Wetherill (KRW; 02/2000 - 08/2009);  Michell Thomey (MLT; 09/2005 - 08/2008), Heather Simpson (HLS; 08/2000 - 08/2002), Chris Roberts (CR; 09/2001- 08/2002), Shana Penington (SBP; 01/2000 - 08/2000), Seth Munson (SMM; 09/2002 - 06/2004), Jay McLeod (JRM; 01/2006 - 08/2006); Caleb Hickman (CRH; 09/2002 - 11/2004), Charity Hall (CLH; 01/2005 -  01/2006), Tessa Edelen (MTE, 08/2004 - 08/2005).

Linking Precipitation and C3 - C4 Plant Production to Resource Dynamics in Higher Trophic Level Consumers: Plant Data (2005-2006)

Abstract: 

In many ecosystems, seasonal shifts in temperature and precipitation induce pulses of primary productivity that vary in phenology, abundance and nutritional quality.  Variation in these resource pulses could strongly influence community composition and ecosystem function, because these pervasive bottom-up forces play a primary role in determining the biomass, life cycles and interactions of organisms across trophic levels.  The focus of this research is to understand how consumers across trophic levels alter resource use and assimilation over seasonal and inter-annual timescales in response to climatically driven changes in pulses of primary productivity. We measured the carbon isotope ratios (d13C) of plant, arthropod, and lizard tissues in the northern Chihuahuan Desert to quantify the relative importance of primary production from plants using C3 and C4 photosynthesis for consumers.  Summer monsoonal rains on the Sevilleta LTER in New Mexico support a pulse of C4 plant production that have tissue d13C values distinct from C3 plants.  During a year when precipitation patterns were relatively normal, d13C measurements showed that consumers used and assimilated significantly more C4 derived carbon over the course of a summer; tracking the seasonal increase in abundance of C4 plants.  In the following spring, after a failure in winter precipitation and the associated failure of spring C3 plant growth, consumers showed elevated assimilation of C4 derived carbon relative to a normal rainfall regime. These findings provide insight into how climate, pulsed resources and temporal trophic dynamics may interact to shape semi-arid grasslands such as the Chihuahuan Desert in the present and future.

Data set ID: 

269

Additional Project roles: 

270

Core Areas: 

Keywords: 

Methods: 

Study site: 

This research was conducted on the Sevilleta LTER, located 100 km south of Albuquerque, New Mexico, which is an ecotonal landscape of Chihuahuan desert shrub and grasslands (Muldavin et al. 2008).  Data were collected from a 0.9 x 0.5km strip of land that encompassed a flat bajada and a shallow rocky canyon of mixed desert shrub and grassland dominated by the creosote bush (Larrea tridentata) and black grama grass (Bouteloua eriopoda). 

Tissue collection & sample preparation for stable isotope analysis:

From May to October of 2005 and 2006 we collected plant, lizard, and arthropod tissues for carbon stable isotope analysis. During mid-summer of 2005, we randomly collected leaf and stem samples from the 38 most abundant species of plants; these species produce over 90% of the annual biomass on our study site (see Appendix Table A).  Approximately 3.5 mg of plant material was then loaded into pre-cleaned tin capsules for isotope analysis.  

Data sources: 

sev269_plant_isotope_20140520.csv

Pollinator Monitoring Study in the Chihuahuan Desert Grasslands and Creosote Shrubland at the Sevilleta National Wildlife Refuge, New Mexico (2000-present)

Abstract: 

This study is designed to look at community or population level fluctuations in bees over the
season and on a long term basis, over years. Funnel traps are a very low maintenance method of
trapping pollinators with zero human bias. The bias of the traps is that the color determines the
species and sexes that it attracts. Therefore the traps provide relative abundance that can be
compared over the season or year, but individual species cannot be compared within a season. This
study is designed to be compared with the data from SEV137 Phenology, to look at spatial and
temporal patterns within pollinator and flowering plant communities. Data is not available at this
time, but the species list is.

Core Areas: 

Data set ID: 

135

Keywords: 

Methods: 

Activating and collecting the traps

When the traps are activated, the worker need only a screwdriver to open the cans and a gallon of propylene glycol to fill the traps. After major rain events, the watered down glycol is collected for disposal and the trap is refilled with undiluted glycol.

To collect the specimens, the worker carries 10 small kitchen strainers, a pint size plastic cup and a hammer. The specimens are strained and the old antifreeze is placed back in the paint can. The funnel is left inside the cage with the closed paint can for the inactive period.

Back at the truck, the specimens are transferred into labelled vials with 70% ethyl alcohol and stored until they can be processed.

Lab Processing

In the lab, the specimens are rinsed of any left over glycol and pinned and labelled according to museum standards. All of 2001 specimens were pinned. In 2002, some of the more common species or species groups were not pinned, but were stored in alcohol with the non-target specimens.

Identifications

Identifications are done by Karen Wetherill (Sevilleta LTER) and Terry Griswold (USDA Bee Laboratory, Logan, Utah). Twenty specimens of each  species or morphotype are deposited in the Museum of Southwestern Biology (MSB) and 20 are deposited in the arthropod collection of the  Sevilleta Long Term Ecological Research Station which is a permanent loan from the MSB. Some specimens were retained by the USDA Bee Laboratory in Logan, Utah. Host codes are Kartez Plant codes as listed on the USDA Plants Database.

Sampling design

One blue trap and one yellow trap were installed 10m north or 10m south of each phenology transect. The north or south location of each color of trap was decided by flipping a coin. The phenology transects are the north/south lines of each rodent trapping web and are 200m long. There are five rodent trapping webs at each of the three sites, totalling 30 traps, 15 of each color. One sample equals the sum of one yellow trap and one blue trap.

The traps consist of a 2 foot high chicken wire cage with a platform 1 1/2 feet off the ground. The cage prevents wildlife from disturbing  the traps. The trap itself rests on the platform and is made up of a one quart paint can with about an inch of propylene glycol and a yellow or blue automotive funnel with a heavy section of pipe glued around the spout to prevent the wind from blowing the funnel. The funnels have been sprayed with blue and yellow Krylon brand flourescent spray paint. The lid of the paint can is left in the cage to close the can when the trap is inactive.

The traps are activated in March every year and are left open for 14 days at which point the specimens are collected and the traps are closed for another 14 days. This cycle repeats itself through the month of October.

Maintenance: 

This file was created on Jan. 14, 2003 by Kristin Vanderbilt.

This study began in February of 2001. The first year is to be considered a pilot study as the methods changed for 2002. In the first year, pan traps were used. These were replaced by funnel traps for the year 2002.

This file was updated by Karen Wetherill on March 10, 2004 and again on December 7, 2005 and again on July 9, 2008.

Quality Assurance: 

All identifications were verified at the USDA Bee Laboratories in Logan, Utah with the help of Dr. Terry Griswold.

Additional information: 

Information on data collection

In 2001, the samples were collected once a month, during the same time as the phenology data. Yellow pan traps were put out for 48 hours (or shorter due to evaporation). In 2002, after the traps were replaced with funnel traps which use antifreeze rather than water, the traps were left open for two weeks and then closed for two weeks from February through October.

In August 2002, the traps were accidentally closed one week early and then reset for an additional week (August 30th to September 6th) so these samples will be more like the September samples than they are like the July samples.

In 2004 the February collection was not taken.

Additional Study Area Information

Study Area 1

Study Area Name: Blue Grama Core Site

Study Area Location: The Blue Grama Core Site is one of 5 current core SEVLTER study sites. Core studies include meteorology, rodent abundance, pollinator diversity, monthly phenology, and NPP. Additional studies have examined the Bootleg Canyon fire of 1998 and grass patch dynamics.

Elevation: 1670 m

Vegetation: Vegetation is characterized as Plains-Mesa Grassland, dominated by blue and black gramma (Bouteloua gracilis & B. eriopoda) and galleta grass (Hilaria jamesii)

North Coordinate:34.3348
South Coordinate:34.3348
East Coordinate:106.631
West Coordinate:106.631

Study Area 2

Study Area Name: Five Points Creosote Core Site

Study Area Location: Five Points is the general area which emcompasses the Black Grama Grassland (known as Five Points Grassland) and Creosote Core (Five Points Larrea) study sites and the transition between Chihuahuan Desert Scrub and Desert Grassland habitats. Both core sites are subject to intensive research activities, including measurements of NPP, phenology, pollinator diversity, and ground dwelling arthropod and rodent populations. There are drought rain-out shelters in both the Grassland and Creosote sites, as well as another set in the mixed ecotone with co-located ET Towers. The grassland Small Mammal Exclosure Study is located here, as well as many plots related to patch mapping and biotic transitions.

Elevation: 1615 m

Vegetation: The Creosote Core site is characterized as Chihuahuan Desert Scrub, dominated by a creosotebush overstory, with broom snakeweed, purple pricklypear (O. macrocentra) and soapweed yucca as notable shrubs. The site is also characterized by numerous, dense grass dominated patches, reflecting proximity to the Black Grama Core site and the presumably recent appearance of creosotebush. Dominant grasses were black grama, fluffgrass (Dasyochloa pulchellum), burrograss (Scleropogon brevifolia), bushmuhly (M. porteri), and galleta (Pleuraphis jamesii). Notable forb species included field bahia (Bahia absinthifolia), baby aster (Chaetopappa ericoides), plains hiddenflower, Indian rushpea (Hoffmannseggia glauca), Fendler’s bladderpod (Lesquerella fendleri), and globemallow.

North Coordinate:34.3331
South Coordinate:34.3331
East Coordinate:106.736
West Coordinate:106.736

Study Area 3

Study Area Name: Five Points Grass Core Site

Study Area Location: Five Points is the general area which emcompasses the Black Grama Grassland (known as Five Points Grassland) and Creosote Core (Five Points Larrea) study sites and the transition between Chihuahuan Desert Scrub and Desert Grassland habitats. Both core sites are subject to intensive research activities, including measurements of NPP, phenology, pollinator diversity, and ground dwelling arthropod and rodent populations. There are drought rain-out shelters in both the Grassland and Creosote sites, as well as another set in the mixed ecotone with co-located ET Towers. The grassland Small Mammal Exclosure Study is located here, as well as many plots related to patch mapping and biotic transitions.

Elevation: 1616 m

Vegetation: Desert Grassland habitat is ecotonal in nature and the Black Grama Core site is no exception, bordering Chihuahuan Desert Scrub at its southern boundary and Plains-Mesa Grassland at its northern, more mesic boundary. There is also a significant presence of shrubs, dominantly broom snakeweed (Gutierrezia sarothrae), along with less abundant fourwing saltbush (Atriplex canescens), Mormon tea (Ephedra torreyana), winterfat (Krascheninnikovia lanata), tree cholla (Opuntia imbricata), club cholla (O. clavata), desert pricklypear (O. phaeacantha), soapweed yucca (Yucca glauca), and what are presumed to be encroaching, yet sparsely distributed, creosotebush (Larrea tridentata). Characteristically, the dominant grass was black grama (Bouteloua eriopoda). Spike,  sand, and mesa dropseed grasses (Sporobolus contractus, S. cryptandrus, S. flexuosus) and sand muhly (Muhlenbergia arenicola) could be considered co-dominant throughout, along with blue grama  (B. gracilis) in a more mesic, shallow swale on the site. Notable forb species included trailing four o’clock (Allionia incarnata), horn loco milkvetch (Astragalus missouriensis), sawtooth spurge  (Chamaesyce serrula), plains hiddenflower (Cryptantha crassisepala), blunt tansymustard (Descarania obtusa), wooly plaintain (Plantago patagonica), globemallow (Sphaeralcea wrightii), and mouse ear (Tidestromia lanuginosa).

North Coordinate:34.3381
South Coordinate:34.3381
East Coordinate:106.717
West Coordinate:106.717

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