@article {50376, title = {Global desertification: building a science for dryland development}, journal = {Science}, volume = {316}, year = {2007}, note = {//??//LTER-V//entered 08/15/2007}, month = {2007}, pages = {847-851}, abstract = {

In this millennium, global drylands face a myriad of problems that present tough research, management, and policy challenges. Recent advances in dryland development, however, together with the integrative approaches of global change and sustainability science, suggest that concerns about land degradation, poverty, safeguarding biodiversity, and protecting the culture of 2.5 billion people can be confronted with renewed optimism. We review recent lessons about the functioning of dryland ecosystems and the livelihood systems of their human residents and introduce a new synthetic framework, the Drylands Development Paradigm (DDP). The DDP, supported by a growing and well-documented set of tools for policy and management action, helps navigate the inherent complexity of desertification and dryland development, identifying and synthesizing those factors important to research, management, and policy communities.

}, keywords = {DDP, degradation, desertification, development, Drylands Development Paradigm, global}, doi = {10.1126/science.1131634 }, url = {/files/bibliography/07-012.pdf}, author = {J. F. Reynolds and D. Mark Stafford Smith and E. Lambin and B.L. Turner II and Mortimore, Michael and Batterbury, Simon P.J. and Downing, Thomas E. and Dowlatabadi, Hadi and Roberto J. Fern{\'a}ndez and Jeffrey E. Herrick and E. Huber-Sannwald and Jiang, Hong and Leemans, Rik and Lynam, Tim and F. Maestre and M. Ayarza and Brian Walker} } @conference {50499, title = {An international research network for testing the Dahlem Desertification Paradigm (DDP)}, booktitle = {Global Environmental Change: Regional Challenges. An Earth System Science Partnership, Open Science Conference}, year = {2006}, month = {November 9-12, 2}, pages = {661}, address = {Beijing, China}, abstract = {Historically, debates associated with global desertification have focused on the underlying causes of land degradation; the extent to which changes are natural (e.g., climate-driven) vs. anthropogenic (e.g., over-grazing); {\textquoteleft}grass-roots{\textquoteright} abatement efforts vs. scientific ones; the amount of land affected or {\textquoteleft}at risk{\textquoteright}; and whether or not desertification is reversible. Since stakeholders tend to employ disciplinary arguments in the debate, the end product is confusion and disagreement. Hence, there is an urgent need for new thinking beyond regional and disciplinary concerns. We argue that when desertification is viewed in the context of coupled human environmental systems, many of the scientific, political and social issues of desertification seem tractable. We have developed a new synthetic framework: the Dahlem Desertification Paradigm (DDP), which consists of 9 assertions and yields testable hypotheses to move the debate forward. We are applying the DDP to diverse ecosystems throughout the world via ARIDnet (assessment, research, and integration of desertification research network), an international initiative that emphasizes the importance of interdependencies of natural and human systems. The general objectives of ARIDnet are to foster international cooperation and exchange of ideas about desertification as summarized in the DDP; to open communication channels to foster more practical, field-level interactions with stakeholders in sustainable land management; and to use the concepts, experiences, and applications developed by participants to support on-going international discussions on the principles, criteria, and policies related to global desertification, especially the Convention to Combat Desertification.}, keywords = {climate, global desertification, natural}, author = {J. F. Reynolds and M. Ayarza and Jeffrey E. Herrick and E. Huber-Sannwald and E. Lambin and D. Mark Stafford Smith} } @inbook {50498, title = {Modeling the unique attributes of aridland ecosystems: Lessons from the Jornada Basin}, booktitle = {Structure and Function of a Chihuahuan Desert Ecosystem: The Jornada Basin Long-Term Ecological Research Site}, year = {2006}, month = {July 1, 2006}, pages = {321-353}, publisher = {Oxford University Press}, organization = {Oxford University Press}, chapter = {16}, address = {New York, NY}, abstract = {The Jornada Basin is typical of aridland ecosystems of the southwestern United States and many other regions of the globe: it is water-limited with low annual net primary production (ANPP) and low-standing crop (Szarek 1979; Ludwig 1987). Yet, paradoxically, aridland ecosystems are structurally and functionally quite complex, exhibiting a remarkable range of species compositions and system behaviors. This can be attributed, in part, to the presence of complex topography and landscape physiography which, when combined with extreme variability in precipitation, produces striking spatial and temporal heterogeneity in the availability of essential limiting resources such as water and mineral nutrients.}, keywords = {aridland, ecosystems, paradixically, production, water-limited}, url = {/files/bibliography/06-067.pdf}, author = {J. F. Reynolds and P. R. Kemp and Ogle, K. and Roberto J. Fern{\'a}ndez and Q. Gao and Jianguo Wu}, editor = {Kris Havstad and L. Huenneke and W. H. Schlesinger} } @conference {50594, title = {Applying a new desertification paradigm linking biophysical and socioeconomic elements: the Amapola, Mexico, case study}, booktitle = {Society for Range Management, 58th Annual Meeting and Trade Show}, year = {2005}, month = {February 5, 2005}, pages = {Paper No. 282}, address = {Fort Worth, TX}, abstract = {

The Dahlem Desertification Paradigm (DDP) is a new, interdisciplinary framework stemming from the 88th Dahlem workshop: An Integrated Assessment of the Ecological, Meteorological and Human Dimensions of Global Desertification. The DDP focuses on interrelationships within coupled human-environment systems that cause desertification and is designed to facilitate our ability to compare and contrast arid and semiarid regions of the world. We present elements of the DDP as applied to a case study of severe land degradation in La Amapola, one of the most remote and inaccessible communities of the Ejido Escalerillas, situated on the SE side of the Sierra San Miguelito, SW of San Luis Potosi, Mexico. The structural heterogeneity shaping the Amapola landscape is the product of 150 yrs of human activity and climatic change, where historic legacies remain important. Amapola is a dynamic, coupled human-environmental system dominated by numerous biophysical variables (especially hydrologic phenomena such as soil erosion, gullies, flooding, man-made water reservoirs, etc.) and socioeconomic variables (changing land tenure, federal self-help assistance programs, complex community leadership hierarchies, poverty, etc.). We applied the DDP framework to the degraded Amapola ecosystem to elucidate key linkages between these biophysical and socioeconomic variables with the goal of assessing, for example, the likelihood for increased crop productivity, the potential to extend existing rain-fed and irrigated cultivation via changes in local hydrology, and the relative contribution and interactions of a number of possible degradation triggers, such as overgrazing, hydrologic intervention, and climate variability, especially linkages to the socioeconomic system.

}, keywords = {Amapola, Mexico, biophysical, case study, desertification paradigm, socioeconomic}, author = {J. F. Reynolds and E. Huber-Sannwald and F. Maestre and Jeffrey E. Herrick and Healy, R.} } @article {50593, title = {Aspectos Socioeconomicos Y Biofisicos de la Desertificaction}, journal = {International Journal of Ecology and Evironmental Sciences}, year = {2005}, month = {September 30, 20}, abstract = {Land degradation and desertification are among the most important environmental issues being faced by drylands. Despite its importance and the enormous research effort devoted to it in the last decades, desertification is a topic surrounded by controversy and disagreement. This controversy is rooted in the traditional separation of the biophysical and socio-economic dimensions of desertification, which have been studied separately by scientists from both the natural and the social sciences. This separation has been fueled by the lack of a conceptual and synthethic framework suited to deal with both dimensions simultaneously. In this article we review the main topics surrounding desertification, introduce a new conceptual framework designed to study the biophysical and socio-economic dimensions of desertification simultaneously, review some of the measures being carried out to manage desertified lands and discuss some of the main challenges ahead in the research and management arenas.}, keywords = {degradation, desertification}, url = {/files/bibliography/05-019.pdf}, author = {J. F. Reynolds and F. Maestre and E. Huber-Sannwald and Jeffrey E. Herrick and P. R. Kemp} } @inbook {51035, title = {Desertification}, booktitle = {Encyclopedia of Biodiversity, Volume 2}, year = {2001}, note = {//NONE//NONE//ProCite field[6]: InProCite field[8]: Editor-in-ChiefProCite field[36]: In}, month = {2001}, pages = {61-78}, publisher = {Academic Press}, organization = {Academic Press}, address = {San Diego, CA}, abstract = {The phenomenon of desertification involves the loss of biological or economic productivity and biodiversity in arid and semiarid croplands, pastures, rangelands, and subhumid woodlands due mainly to nonsustainable human activities, such as overcultivation, fuel gathering, overgrazing by domestic animals, deforestation, and poor irrigation practices, and is often triggered or exacerbated by climate variability, mainly drought.}, keywords = {book, books, chapter, chapters, desertification, model, desertification, report, reports}, author = {J. F. Reynolds}, editor = {Simon Asher (ed. Levin} } @inbook {51034, title = {Non-Equilibrium Ecology}, booktitle = {Encyclopedia of Global Environmental Change, Volume Two}, year = {2001}, note = {//NONE//NONE//ProCite field[6]: In}, month = {2001}, publisher = {John Wiley \& Sons}, organization = {John Wiley \& Sons}, abstract = {One of the most controversial and well-known theories associated with global change is the Gaia hypothesis. Originated by biologist James Lovelock, this hypothesis states that over geologic time, biotic life on Earth has evolved to "control" the physical forces of nature, resulting in a bio-geosphere that is self-regulatory, or homeostatic. Thus, acting like the thermostat in your house, any deviation from this balanced condition or set-point will result in a "corrective" response in order to maintain the stable equilibrium. Do ecosystems behave this way? If so, predicting their response to global change would be relatively easy. However, notions of stable equilibria -- as espoused by the Gaia hypothesis -- are centered around the concept of the balance of nature, which has dictated western views of science since antiquity. It is ironic that the Gaia hypothesis is receiving such popular attention at a time when ecologists are eschewing the equilibrium-centered view per se in favor of a non-equilibrium one. During the past several decades ecology has experienced a paradigm shift: from the balance of nature to equilibrium/stability to non-equilibrium. This paradigm shift, which embraces spatio-temporal dynamics of ecosystems, is essential to our ability to develop a predictive understanding of the dynamics of ecosystems.}, keywords = {book, books, chapter, chapters, global change, model, model, Gaia, model, non-equilibrium ecology, report, reports}, author = {J. F. Reynolds}, editor = {Mooney, H. A. and J. Canadell} } @inbook {51111, title = {Drylands and global change: Rainfall variability and sustainable rangeland production}, booktitle = {Proceedings of the 12th Toyota Conference: Challenge of Plant and Agricultural Sciences to the Crisis of the Biosphere on the Earth in the 21st Century}, year = {2000}, note = {//NMSU,USDA//LTER III//ProCite field[6]: In}, month = {2000}, pages = {73-86}, publisher = {R. G. Landes Company}, organization = {R. G. Landes Company}, address = {Austin, Texas}, abstract = {This chapter reviews the extent of global change in drylands and some of its ecological and societal consequences. It also discusses rainfall variability as one component of potential climate change and how it affects primary production in rangelands. This is illustrated with a case study of a rangeland in southern New Mexico using a physiologically-based ecosystem model. It suggests that basic ecological knowledge should be an essential component of assessment frameworks.}, keywords = {book, books, chapter, chapters, climate variability, global change, desertification, global change, rainfall variability, global change, rangeland production, model, PALS, plant production, rainfall variability, rainfall, global change, rainfall, rangeland production, rangeland production, global change, report, reports}, author = {J. F. Reynolds and Roberto J. Fern{\'a}ndez and P. R. Kemp}, editor = {Watanabe, K. N. and Komanine, A. (eds.)} } @article {51110, title = {Effects of long-term rainfall variability on evapotranspiration and soil water distribution in the Chihuahuan Desert: A modeling analysis}, journal = {Plant Ecology}, volume = {150}, year = {2000}, note = {//NMSU//LTER III//}, month = {2000}, pages = {145-159}, abstract = {

We used the patch arid land simulator (PALS-FT) -- a simple, mechanistic ecosystem model -- to explore long-term variation in evapotranspiration (ET) as a function of variability in rainfall and plant functional type (FT) at a warm desert site in southern New Mexico. PALS-FT predicts soil evaporation and plant transpiration of a canopy composed of five principal plant FTs: annuals, perennial forbs, C4 grasses, sub-shrubs, and evergreen shrubs. For each FT, the fractional contribution to transpiration depends upon phenological activity and cover as well as daily leaf stomatal conductance, which is a function of plant water potential, calculated from root-weighted soil water potential in six soil layers. Simulations of wat6er loss from two plant community types (grass- vs. shrub-dominated) were carried out for the Jornada Basin, New Mexico, using 100 years of daily precipitation data (1891-1990). In order to emphasize variability associated with rainfall and fundamental differences in FT composition between communities, the seasonal patterns cover of perennials were held constant from year to year. Because the relative amount of year to year cover of winter and summer annual species is highly variable in this ecosystem, we examined their influence on model predictions of ET by allowing their cover to be variable, fixed, or absent. Over the entire 100-yr period, total annual ET is highly correlated with total annual rainfall in both community types, although T and E alone are less strongly correlated with rainfall, and variation in transpiration is nearly 3 times greater than evaporation and 2 times greater than variation in rainfall (CV of rainfall = 35\%). Water use shows a relatively high similarity between the grass- and shrub-dominated communities, with a 100-yr average T/ET of 34\% for both communities. However, based on a year-by-year comparison between communities, T/ET was significantly greater in the grass-dominated community, reflecting the fact that over the long term more than half of the rain occurs in the summer and is used slightly more efficiently (T\>E) by the C4-grass community than the shrub community, although we found some rainfall patterns that resulted in much greater T/ET in the shrub community in a given year. Percent of water lost as transpiration (T/ET) suggests that while there is a general trend toward increased T/ET with rainfall in both community types, T/ET is extremely variable over the 100-yr simulation, especially for normal and below normal amounts of rainfall (T/ET values range from 1 to 58\% for the grass-dominated site and 6 to 60\% for the shrub-dominated site). These predictions suggest that because of the relatively shallow distribution of soil water, there is little opportunity for vertical partitioning of the soil water resource by differential rooting depths of the plant FTs. However, functional types may avoid competition by keying on particular "windows" of moisture availability via differences in phenologies. We found very little differences in average, long-term model predictions of T, E, and ET when annual plant cover was variable, fixed, or absent. The results of our simulations help reconcile some of the disparate conclusions drawn from experimental studies about the relative contribution of transpiration vs. evaporation to total evapotranspiration, primarily by revealing the great year-to-year variability that is possible.

}, keywords = {article, articles, Bouteloua, evapotranspiration, desertification, model, evapotranspiration, Boutelous eriopoda, evapotranspiration, rainfall, evapotranspiration,grassland, evapotranspiration,model, grass, evapotranspiration, journal, journals, Larrea, evapotranspiration, model,, model, PALS, model, rainfall variability, model, soil water distribution, rainfall, evaporation, rainfall, soil water, shrubs, evapotranspiration, soil water, evapotranspiration, soil water, rainfall}, doi = {10.1023/A:1026530522612}, url = {files/bibliography/JRN00299.pdf}, author = {J. F. Reynolds and P. R. Kemp and Tenhunen, J. D.} } @inbook {51184, title = {Do landscape structural and functional units exist?}, booktitle = {Integrating Hydrology, Ecosystem Dynamics, and Biogeochemistry in Complex Landscapes}, year = {1999}, note = {//NMSU,USDA//LTER III//ProCite field[6]: InProCite field[36]: In}, month = {1999}, pages = {273-296}, publisher = {John Wiley and Sons}, organization = {John Wiley and Sons}, address = {Chichester, U.K.}, abstract = {

The complexity of landscapes requires that simplified constructs or frameworks be developed for understanding and predictions. Toward this goal, the question is posed, "Do landscape structural and functional units exist?" The argument is in favor of the existence of landscape units, but acknowledge that there are no generic recipes for simplifying the real world for use in landscape models. While simplification is the key to achieving understanding and prediction, explicit consideration of scale multiplicity in studying complex landscapes is dictated by the hierarchical properties of landscapes. Therefore, we suggest that the hierarchical patch dynamics paradigm provides a conceptual framework to accomplish these objectives.

}, keywords = {biogeochemistry, ecosystem dynamics, biogeochemistry, hydrology, book, books, chapter, chapters, hydrology, biogeochemistry, hydrology, ecosystem dynamics, landscape, biogeochemistry, landscape, ecosystem dynamics, landscape, hydrology, model, landscape, report, reports}, url = {files/bibliography/JRN00274.pdf}, author = {J. F. Reynolds and Jianguo Wu}, editor = {Tenhunen, J. D. and P. (eds.) Kabat} } @article {51185, title = {Impact of drought on desert shrubs: Effects of seasonality and degree of resource island development}, journal = {Ecological Monographs}, volume = {69}, number = {1}, year = {1999}, month = {February 1, 1999}, pages = {69-106}, abstract = {

Large areas of semiarid grasslands in the southwestern United States have been virtually replaced by shrubs during the past century. Understanding the causes and consequences of such vegetation dynamics requires that we elucidate the interplay between external forces of change (e.g., climate, human impacts) and the internal forces within these ecosystems that foster resilience and/or stability. Several conceptual models of and ecosystems address this interplay by including the potential role of autogenic shrub effects on ecosystem processes that lead to the formation of "resource islands" and tend to promote shrub persistence. Specifically, during the process of shrub establishment and maturation, the cycling of nutrients is progressively confined to the zones of litter accumulation beneath shrubs, while bare intershrub spaces become increasingly nutrient poor. As shrub resource islands develop, there is increased interception and stemfiow by shrub canopies, confining infiltration of nutrient-enriched rainfall directly beneath the shrubs; the barren intershrub spaces generate overland flow, soil erosion by wind and water, and nutrient losses. These islands are preferred sites for the regeneration of shrubs and herbaceous plants and are correlated with spatial variation in soil microbial populations and soil microfauna that promote nutrient cycling. If further changes in the transition between grassland and shrubland are to be correctly predicted, or if we wish to intervene and redirect transitions, we must develop a greater mechanistic understanding of the structural and functional relationships between shrubs and the resource islands associated with them.

}, keywords = {desertification, drought response, Jornada LTER, Larrea tridentata, prosopis glandulosa, resource island formation, shrub physiology, soil nitrogen, soil water}, doi = {10.2307/2657195 }, url = {/files/bibliography/680.pdf}, author = {J. F. Reynolds and R. A. Virginia and P. R. Kemp and A.G. de Soyza and Tremmel, D. C.} } @book {51299, title = {Defining plant functional types for models of desertification}, series = {Plant Functional Types}, year = {1997}, note = {//NMSU, USDA//LTER III//ProCite field[6]: In}, month = {1997}, pages = {195-216}, publisher = {Cambridge University Press}, organization = {Cambridge University Press}, address = {Cambridge}, keywords = {book, books, chapter, chapters, desertification, model, model, desertification, report, reports}, author = {J. F. Reynolds and R. A. Virginia and W. H. Schlesinger}, editor = {Smith, T. M. and Shugart, H. H. and Woodward, F. I. (eds.)} } @article {51298, title = {Modularity and genericness in plant and ecosystem models}, journal = {Ecological Modelling}, volume = {94}, year = {1997}, note = {//??//LTER III//}, month = {1997}, pages = {7-16}, abstract = {

In this paper, we present definitions of modularity and genericness that are based on sets of criteria and rules for model design and which encompass the goal of developing an efficient and flexible structure for plant and ecosystem models. Model structure should be based on modules that (1) relate directly to real world components or processes; (2) have input and output variables that are measurable values; and (3) communicate solely via these input and output variables. Such a model structure has the advantage that it can be incrementally improved by simply replacing one module with another that has the same input and output variables. The underlying mechanism in the replacement module can be different, which facilitates the incorporation of the latest experimental research results and allows modelers to readily test alternative hypotheses about mechanisms. Thus, modularity and genericness open models to contributions from many authors, facilitate the comparison of alternative hypotheses, and extend the life and utility of simulation models.

}, keywords = {article, articles, ecosystem, model, journal, journals, model, ecosystem, model, plant, plant, model}, doi = {10.1016/S0304-3800(96)01924-2}, url = {files/bibliography/JRN00247.pdf}, author = {J. F. Reynolds and Acock, B.} } @article {51368, title = {Modelling whole-plant allocation in relation to carbon and nitrogen supply: Coordination versus optimization: Opinion}, journal = {Plant and Soil}, volume = {185}, year = {1996}, note = {//??//LTER-III//}, month = {1996}, pages = {65-74}, abstract = {

One of the few integrating theories related to allocation is the hypothesis of optimization. While optimization theory has great heuristic appeal and has been used to describe a range of physiological and ecological phenomena, it has major limitations. Optimization is necessarily based on a definite time integral and an optimal control strategy must be specific to the same patterns exhibited by the driving variables over this same period of time. Optimization tends to employ the use of oversimplifications in order to facilitate analytical solutions to the optimal control strategy, i.e. the mechanism governing the response of plants, which is the critical issue of interest. It is difficult to define objective criteria that can account for the natural variability in plants and testing the quantitative predictions of optimality models is also difficult. Thus, we suggest that optimization theory is too limited for practical use in modelling whole plant allocation. In this paper, we introduce the use of coordination theory as a practical alternative. We develop a simple plant growth allocation model using both coordination and optimization approaches and show that coordination theory is easily applied, produces results that are quantitatively similar to optimization, and overcomes the inherent limitations of optimization theory.

}, keywords = {article, articles, carbon, model, journal, journals, model, resource allocation, nitrogen, model, plant, model}, doi = {10.1007/BF02257565}, url = {files/bibliography/JRN00211.pdf}, author = {J. F. Reynolds and J. Chen} } @article {51544, title = {Modeling the effects of elevated carbon dioxide on plants: extrapolating leaf response to a canopy}, journal = {Journal of Agricultural and Forest Meteorology}, volume = {61}, year = {1992}, note = {//OTHER//NONE//}, month = {1992}, pages = {69-94}, keywords = {article, articles, carbon dioxide,model, journal, journals, model,carbon dioxide, plants,carbon dioxide model}, author = {J. F. Reynolds and J. Chen and Harley, P. C. and Hilbert, D. W. and Dougherty, R. L. and Tenhunen, J. D.} } @book {51851, title = {Adaptive strategies of desert shrubs with special reference to the creosotebush (Larrea tridentata [DC] Cov.)}, series = {Pattern and Process in Desert Ecosystems}, year = {1986}, note = {//NMSU//NONE, LTER//ProCite field[6]: In}, month = {1986}, pages = {19-49}, publisher = {University of New Mexico Press}, organization = {University of New Mexico Press}, address = {Albuquerque, New Mexico}, abstract = {In this paper, my objective is, first, to discuss the biology of the creosotebush in terms of a static definition of its adaptive strategy, and, second, to present an overview of the approach that we{\textquoteright}re using to model the dynamic features of the adaptive strategy of Larrea in the Chihuahuan Desert. The value of the approach for hypothesis testing will be evaluated with regard to its potential as a tool for increasing our understanding of plant adaptations in arid environments.}, keywords = {book, books, chapter, chapters, Larrea, adaptive strategies, model,Larrea, model,shrubs,adaptive strategies, report, reports, shubs, adaptive strategies}, author = {J. F. Reynolds}, editor = {Walter G. Whitford} } @article {52049, title = {Validation of primary production model of the desert shrub Larrea tridentata using soil-moisture augmentation experiments}, journal = {Oecologia}, volume = {51}, year = {1981}, note = {//NMSU//US-IBP//}, month = {1981}, pages = {357-363.}, abstract = {In previous papers we have described and verified a primary production model of the desert shrub Larrea tridentata. Here we address the validation phase of the evaluation of this model. Two versions of the model which differ in the priority scheme used for allocating carbon to reproductive or vegetative organs were compared on the basis of their usefulness and reliability over a range of soil-moisture conditions. Over an entire growing season when soil-moisture conditions were near "normal" both versions of the model were adequate predictors of total above-ground vegetative growth and one was an adequate predictor of reproductive growth as well. A more detailed analysis revealed that the versions varied in the range of soil-moisture conditions over which they were adequate and that neither was adequate when soil-moisture had remained high for extended periods. The validation process has revealed some likely areas for model improvement to increase adequacy.}, keywords = {article, articles, journal, journals, Larrea,productivity model, Larrea,soil-moisture augmentation, model, Larrea, model,primary production, plant, Larrea, rainfall simulation,Larrea}, author = {J. F. Reynolds and Gary L. Cunningham} } @proceedings {52099, title = {Modeling Yucca primary productivity: substrate requirements for growth}, year = {1980}, note = {//LOCAL//NONE//ProCite field[6]: In}, month = {1980}, pages = {69-82}, publisher = {Centro de Investigacion en Quimica Aplicada}, abstract = {A preliminary study was conducted to examine the importance of including substrate costs of plant tissue biosynthesis in growth models of Yucca. The biochemical composition of plant tissue form select organs of Y. elata and Y. baccata were determined and used in the Penning de Vries model to compute the necessary substrate (glucose) required for their biosynthesis. Through the use of a simple growth model, it was found that substantial predictive error would be introduced if substrate costs were ignored for plant organs deviating significantly from a simple carbohydrate composition.}, keywords = {abstract, abstracts, conference, conference proceedings, conferences, model,Yucca productivity, plant, Yucca, proceeding, proceedings, Yucca,productivity}, author = {J. F. Reynolds and Gary L. Cunningham} } @book {52098, title = {Predicting primary productivity for forest and desert ecosystem models}, series = {Predicting Photosynthesis for Ecosystem Models}, volume = {Volume II}, year = {1980}, note = {//NMSU//US-IBP//ProCite field[6]: In}, month = {1980}, pages = {169-207}, publisher = {CRC Press, Inc.}, organization = {CRC Press, Inc.}, address = {Boca Raton, Florida}, abstract = {A major goal of the Analysis of Ecosystems Program of the U.S. International Biological Program (IBP) was to understand how entire ecosystems function so that their behavior, particularly in response to man-made stresses, might be predictable. A significant part of the research was focused on increasing our knowledge of productivity in natural ecosystems. Productivity was broadly defined so as to include not only energy flux within the trophic structure of the ecosystem but also the attendant water and nutrient fluxes. A major component of the research design in each of the various IBP Biome projects (i.e., grassland, desert, tundra, and deciduous and coniferous forests) was the development of ecosystem-level models of energy and material fluxes.}, keywords = {book, books, carbon allocation, Larrea, carbon-balance paradigm, chapter, chapters, desert, ecosystem models, forest, Larrea,productivity, model, primary productivity, Larrea, model, primary productivity, Pinus, model,carbon-balance, model,growth, model,primary productivity, Pinus,productivity, primary production,model, report, reports, shrub,model}, author = {J. F. Reynolds and Strain, B. R. and Gary L. Cunningham and Knoerr, K. R.}, editor = {Hesketh, J. D. and J. W. Jones (eds.)} } @article {52127, title = {A net CO2 exchange model for Larrea tridentata}, journal = {Photosynthetica}, volume = {13}, number = {3}, year = {1979}, note = {//LOCAL//NONE//}, month = {1979}, pages = {279-286}, abstract = {A net CO2 exchange model for the warm desert evergreen perennial Larrea tridentata (DC) Cov. (creosotebush) was developed using the modeling approach of REED et al. (1976) for the temperate deciduous tree Liriodendron tulipifera L. The approach was very successful using gas exchange measurements on environment chamber-grown Larrea tridentata and hence this approach may have side applicability and versatility for photosynthesis modeling.}, keywords = {article, articles, carbon dioxide exchange, journal, journals, Larrea, Larrea,physiology, Larrea,phytosynthesis, model, photosynthesis, Larrea, model,carbon dioxide, model,Larrea, photosynthesis,Larrea}, author = {J. F. Reynolds and Gary L. Cunningham and J. P. Syvertsen} } @mastersthesis {52284, title = {A comparative modelling study of plant growth systems in a desert ecosystem}, year = {1974}, note = {//NMSU//NONE//}, month = {1974}, pages = {68}, school = {New Mexico State University}, type = {Ph.D. Dissertationpp}, address = {Las Cruces, New Mexico}, abstract = {The use of modeling as a tool in ecosystem analysis has mushroomed in recent years.... Two possible modeling approaches are within quantitative and a qualitative formats. The quantitative approach in ecology usually incorporates the level-rate paradigm of Forrester, utilizing systems of differential equations to describe component relationships. A high level of model precision is one of the objectives. The qualitative approach, as used here, incorporated the pulse-reserve paradigm of Bridges, utilizing blocks of logic statements to test for the presence or absence of specific driving variables. A high level of model realism is one of the goals using this technique. Although void of functional relationships or mechanisms, the pulse-reserve model did offer long-term stability. The reserve-trigger-pulse sequence of the model is biologically real and represents an adaptive strategy for organisms in arid environments. The possibility of expanding this approach for and entire system is discussed. A model is proposed that incorporates the more precise level-rate formulation for primary producers and the pulse-reserve paradigm for higher trophic levels.}, keywords = {dissertation, dissertations, model, level-rate, model, pulse-reserve, model,comparative, model,plant growth, plant growth system,model, productivity,model, theses, thesis}, author = {J. F. Reynolds} }