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LTAR Network Productivity
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Research Program:  Two main components of the research program at the Jornada are 1) the ARS based project "Management Technologies for Arid Rangelands" (2008-2012, USDA ARS Program # 6235-11210-006-00D), and 2) the NSF LTER-based project "Landscape Linkages in Arid and Semi-Arid Ecosystems" (2007-2012; DEB # 0618210).  The ARS project contributes directly to the USDA ARS National Research Program in Pasture, Forage, and Rangeland Systems. The Jornada's base ARS project has four research objectives of 1) developing assessment and monitoring approaches for multi-scale resource evaluations, 2) identifying key ecological processes that influence potential for restoring degraded landscapes, 3) developing adaptive management strategies with application for desert livestock production systems, and 4) predict system responses to both management dependent and independent drivers. The LTER project is conceptually linked to the ARS project in that key hypotheses have application to the ARS research objectives.  The LTER program addresses identification of key processes which redistribute soil resources across spatial scales.  Expanding our understanding of these processes will have direct application to both the management and restoration of arid rangeland systems in the US, throughout North America, and around the world.  Both ARS and LTER projects build intensively and extensively upon the lengthy research history at the Jornada.

     Our overall focus is on driver-pattern-process relationships interacting across spatial and temporal scales that lead to alternative states in linked natural and human-dominated systems.  These interactions have consequences on present and future states, and the goods and services provided by these states (Peters et al. 2006, Fig. 1).  Important modifiers of these relationships are historical legacies and geomorphic templates across these landscapes.  We work at fine to landscape spatial scales so our results have eventual application to the needs of land managers.

Fig. 1. Landscape linkages conceptual framework containing five key elements (legacies, drivers, soil-geomorphic template, transport vectors, resource redistribution) that interact to lead to cascading events and nonlinear dynamics in future states (Peters et al. 2006).

 

Scientific Productivity:  Recent productivity of the Jornada scientific staff as of November, 2011, is illustrated in Fig. 2.  Jornada scientific staff average ~3 peer-reviewed journal articles and ~3 other articles (books and book chapters, proceedings papers, and government documents), excluding abstracts, per scientist per year.  All published manuscripts are posted on line at the Jornada web site within a searchable bibliography that provides direct public access to PDFs of published materials. Publications span from basic ecological studies targeting a scientific peer audience to field guides addressing applied management technologies with a land management practitioner audience.  Periodically, Jornada staff publish syntheses of our scientific work, including special issues of journals (e.g., Estell et al. 2006) or text books summarizing research findings based on our long-term data sets (e.g., Havstad et al. 2006).  Productivity has been enhanced over the past decade by maintaining 4-7 post-doctoral research associate positions within the unit, funded either through ARS or extramural funds, that both support permanent scientific FTE and provide the unit with a dynamic capacity to address emerging issues with needed expertise.

Fig. 2. Number of journal articles (red), books/book chapters/proceedings papers/government publications (blue), and other articles excluding abstracts (green) contributed by Jornada Unit scientists and staff as senior or co-authors from 2007 - 2011. The full searchable bibliography of published research from the Jornada's history contains over 2700 articles.

     Increasingly, our scientific productivity has incorporated perspectives built upon our long term data, and analyzed within scientific collaborations in relationship to other long term data.  A recent example is illustrated in Fig 3 taken from Bestelmeyer et al. (in press in Ecosphere).  This figure illustrates threshold dynamics in penguin populations in Western Antarctic in response to diminishing annual days of sea ice since the early 1970s and a threshold dynamic in perennial grass production in the Chihuahuan Desert (Jornada) in response to the severe drought of the 1950s.  These diverse systems are exhibiting similar transitional dynamics in response to drivers critical within those systems. The Jornada grassland threshold is the first quantitative, published documentation of a transitional vegetative state change in a terrestrial system.

Fig. 3. Results of different sets of time series analyses (A-E) for three species of penguins over 37 years within the Western Antarctic Peninsula (left side) and perennial grass production over 36 years within Jornada pastureland of the northern Chihuahuan Desert (right side).  The penguins are illustrated in three colors (Ad?lie penguins in black, chinstrap penguins in orange, gentoo penguins in blue), and 2 large desert pastures are illustrated in black and orange. These scenes illustrate the following time series analyses: (A) the observed data (either penguin populations or grass production) are shown as points scaled in standard deviation units; (B) the observed driver data (either sea ice duration or amounts of precipitation) are shown as points and the time series as grey lines connecting the points; (C) frequency distributions of penguin populations or grass production; (D) the time series of variance that demonstrate actual thresholds (changes in penguin populations or loss of grass production); (E) the relationship between the driver and response  are illustrated for the initial state (solid symbols, black lines) and post-transition state (open symbols, grey lines); the Antarctic relationship between the driver and response is shown only for Ad?lies because there are too few data for the other species (adapted from Bestelemeyer et al. in press).

 

Selected Bibliography: The following 10 selected recent papers or journal issues originating from our Unit scientists reflect a record of scientific activities of a cross-site and/or networked nature.

Bestelmeyer, B.T., Ellison, A.M., Fraser,W.R., Gorman, K.B., Holbrook, S.J., Laney, C.M., Ohman, M.D., Peters, D.P.C., Pillsbury, F.C., Rassweiler, A., Schmitt, R.J., Sharma, S. 2011. Analysis of abrupt transitions in ecological systems. Ecosphere (In Press).

Peters, D.P.C., Lugo, A.W., Chapin III, F.S., Pickett, S.T.A., Duniway, M., Rocha, A.V., Swanson, F.J., Laney, C., Jones, J. 2011. Cross-system comparisons elucidate disturbance complexities and generalities. Ecosphere 2:art81. doi:10.1890/ES11-00115.1

Herrick, J.E, Lessard, V.C., Spaeth, K.E., Shaver, P.L., Dayton, R.S., Pyke, D.A., Jolley, L., Goebel, J.J.  2010. National ecosystem assessment supported by science and local knowledge. Frontiers in Ecology and the Environment 8:403-408.

Peters, D.P.C., Groffman, P.M., Nadelhoffer, K.J., Grimm, N.B., Collins, S.L., Michener, W.K., Huston, M.A.  2008. Living in an Increasingly Connected World: A Framework for Continental-Scale Environmental Science. Frontiers in Ecology and the Environment 6:229-237.

Rango, A., Martinec, J. Roberts, R.T. Relative importance of glacier contributions to water supply in a changing climate. World Resource Review. 20:487-503. 2008.

Havstad, K.M., Peters, D.P.C., Skaggs, R., Brown, J., Bestelmeyer, B., Fredrickson, E., Herrick, J., Wright, J. 2007. Ecological services to and from rangelands of the United States. Ecological Economics. 64:261-268. 2007.

Peters, D.P.C., Bestelmeyer, B.T., Turner, M.G.  2007. Cross-scale interactions and changing pattern-process relationships: consequences for system dynamics. Ecosystems. 10:790-796.

Peters, D.P.C., Bestelmeyer, B. T., Herrick, J. E., Monger, H.C., Fredrickson, E., Havstad, K. M.  2006. Disentangling complex landscapes: new insights into arid and semiarid system dynamics. BioScience. 56:491-501.

Havstad, K.M., Huenneke, L.F., Schlesinger, W.H., editors. 2006. Structure and Function of a Chihuahuan Desert Ecosystem. The Jornada Basin Long-Term Ecological Research Site. Oxford, NY: Oxford University Press. 492 p.  

Estell, R.E., Fredrickson, E.L., Peters, D.P.C., editors. 2006. Special Issue - Landscape linkages and cross-scale interactions in arid and semi-arid ecosystems. Journal of Arid Environments. 65:193-335.