Ecohydroclimatology of the tropics, with special reference to Ecuador.

• A.  Purpose/Goals

  The new science of ecohydroclimatology goes a step beyond the established fields of bioclimatology and hydroclimatology. Bioclimatology studies the relation between biology/ecology and climate. Hydroclimatology studies the relation between hydrology and climate. Seeking a seamless approach, ecohydroclimatology describes the relation between ecology, hydrology, and climate. While these fields have developed independently of each other, current interdisciplinary demands require that the three fields be joined together into one.

  The purpose of this sabbatical leave is to contribute to the development of the new field of ecohydroclimatology, the study of how local climate and prevailing hydrologic conditions affect the biology and ecology of the surrounding environment. The overall objective of the study is to increase our understanding on how hydrology, a civil engineering field, interacts with ecology in the presence of climate.

  
  

  
  Fig. 1   Mean annual isohyets for Ecuador (mm/yr).
  

  The focus of the data collection is on Ecuador, a country that features a great range of hydrological and ecological settings. In fact, mean annual precipitation in Ecuador varies from as low as 200 mm in the central inland valleys to as high as 7,500 mm in a small region along the northern border (Fig. 1). Thus, there is great moisture variability within a relatively limited geographical range. Note the marked isohyet gradients across the central inland valleys, from 200 to 3,200 mm. This extreme variability within a limited geographical range constitutes a veritable tropical field laboratory, probably unlike no other on Earth. Thus, Ecuador constitutes an excellent location on which to study the effect of climate and hydrology on ecology and biology.

  In addition to the pronounced mean annual isohyet gradients, Ecuador has a wide range of altitudinal variability, from sea level along the western Pacific coast, to 6,238 m above mean sea level at the Chimborazo volcano, the highest in the country. [Curiously, the peak of this volcano stands out as the Earth's shortest distance to the Sun]. The unique combination of mean annual isohyet range and altitudinal variability provides a gamut of geomorphological and hydraulic settings, where the interactions between ecology, hydrology, and climate can be studied in detail.

• B.  Significance

  The proposed study leave is significant because it seeks to link the fields of ecology, hydrology, and climatology into a coherent, seamless, transdisciplinary treatment, where cause/effect relations may be accurately discerned from biofeedback processes. While the field of physics, as applied in climatology and hydrology, is subject to cause/effect relations, the field of ecology has relied more on biofeedback processes. The unraveling of this dichotomy, cause/effect vs biofeedback, stands at the crux of the scientific query in ecohydroclimatology.

  The study leave will use ecohydroclimatological field data collected in Ecuador, for the purpose of establishing characteristic relations in ecology, hydrology, hydrogeology, geomorphology, and climate. A sample of specific questions to be answered are:

  1. What vegetative communities prevail across Ecuador's central valley isohyet gradient?

  2. What are the average and maximum shrub/tree dimensions (height, trunk width, and leaf area index) in a given community?

  3. How are shrub/tree dimensions affected by upland geomorphology?

  4. How are shrub/tree dimensions affected in an upland vegetation/gallery forest geomorphological transect?

  5. How are shrub/tree dimensions affected by the proximity to groundwater?

  6. How are shrub/tree dimensions affected by flow in alluvial aquifers?

  7. How are shrub/tree dimensions affected by flow in fractured rock aquifers?

  8. How does hydrology and climate condition ecotone size in a vegetative community?

  
  

• C.  Procedures
  1. Plan of Activity/Project

     The project plan consists of five phases:

     1. Onsite literature review

     2. Assessment of data needs and sources

     3. Data collection and field visits

     4. Transdisciplinary synthesis

     5. Documentation of research findings.

  2. Timeline of Activity/Project

     The project will start in September 2014 and extend until December 2014. Phases 1 (Onsite literature review) will be carried out during the first part of September. Phase 2 (Assessment of data needs and sources) will be carried out during the latter part of September. Phase 3 (Data collection and field visits) will be carried out during the months of October and November. Phase 4 (Transdisciplinary synthesis) will be carried out during the month of December. Phase 5 (Documentation of research findings) will be carried out during Spring 2015.

     A research report will be produced to document and adequately publicize the findings of the study. The report will be posted online. A scientific journal paper will be submitted for publication in a suitable journal, such as Ecohydrology, Water Resources Research, and International Journal of Bioclimatology and Biometeorology.

  3. Travel or service performed during the period of leave

     Travel to Ecuador will be required as part of the sabbatical leave. Local inspection and field data collection is considered to be an intrinsic part of the proposed research activity. Dr. Fernando Oñate Valdivieso, Chair of the Department of Civil Engineering of the Technical University of Loja (UTPL) has offered to collaborate and participate in the proposed research, and to provide office space, computer and laboratory facilities, and other logistic resources required to acccomplish the project objectives. UTPL is widely recognized as the leading comprehensive institution of technical higher education in Ecuador.

     Prof. Juan Eduardo Leon Ruiz, of the Department of Agronomy at the Politechnic University of Chimborazo (ESPOCH) has committed the participation of ESPOCH in support of the project objectives, including sharing local experience and providing logistic support with data collection.

• D.  List CSU resources, if any, necessary to carry out Activity/Project

  Other CSU facilities to be used include the SDSU Love Library and its extensive online resources. The principal investigator's Visualab, a premiere facility for online data/media research/teaching, will be used as needed to accomplish the project objectives.

• E.  Summary of work already completed on the Activity/Project

  In 1993, the Principal Investigator published a paper entitled: "Vegetated earthmounds in tropical savannas of Central Brazil." This study related, for the first time, the hummock ecosystems of the Great Swamp of Mato Grosso with the prevailing hydrology and geomorphology. Large vegetated hummocks (ecology) in the floodplain of the Great Swamp (hydrology) owe their existence to mound building processes (geomorphology) created by differential sedimentation. Woody vegetation of the cerrado type colonize the mounds in order to thrive in a seasonally hostile (too wet) environment of the campo floodplain (Fig. 2).

  
  Fig. 2   Large vegetated hummock in the Great Swamp of Mato Grosso, Brazil.

  In 2007, the Principal Investigator completed a study entitled: "Impact of the Campo landfill on the hydrology of the Tierra del Sol watershed." In this study, the Principal Investigator documented a potential dependence of the spatial distribution of vegetation on the subsurface local moisture gradients which may be linked to underlying rock fractures. The ecohydrological characteristics of two closely related chaparral species, chamise (Adenostoma fasciculatum) and red shank (Adenostoma sparsifolium), were compared.

  Unlike chamise, red shank violates several definitions of sclerophyllous plants. First, it remains physiologically active during summer drought; thus, it is drought tolerant without being drought dormant. Secondly, its root morphology is unique among the chaparral. Its shallow root system suggests that its moisture for summer growth must come from the top layers of the substrate. Red shank seems to be a type of shrub well adapted to drought conditions, but lacking the obvious morphological characteristics suggesting such adaptability. Thus, the water affinities of red shank appear to lie in between those of the xerophytes, which are well adapted to drought, and those of the mesophytes, which habitually require a more sustained moisture source. The spatial distribution of red shank and its connection to local moisture gradients associated with rock fractures was noted in the study.

  Lastly, the Principal Investigator has recently completed a paper entitled "The 800-mm isohyet: Health and hope." This work pioneers the linkage of classical hydrology with biology/ecology and climatology. The work argues that the 800-mm mean annual isohyet, by virtue of lying in the middle of the precipitation spectrum, features optimum conditions of both water and nutrients, leading to enhanced ecosystem health and a renewed hope for sustainability.

• F.  Brief description of anticipated results

  The project will elucidate ecohydroclimatological relations in a distinct tropical setting, to jump start the transdisciplinary approach to the joint study of vegetation, water, geomorphology, and climate. The study will attempt to answer this fundamental question: How does climate, acting in a defined geomorphological setting and in the presence of water, affects biological productivity, and therefore, ecosystem characteristics and health? The study will contribute to the understanding of natural ecosystem behavior, and thus, of anthropogenic disturbance, leading the way to better management. The findings will have application in water resources engineering and watershed management.

• G.  Benefits to the University and its students

  The benefits to SDSU and its students is guaranteed. Since 1995, the principal investigator teaches a graduate class CIV E 633 "Environmental Hydrology." The average number of students in this class is 15. One of the topics in the course syllabus is Ecohydrology, which deals with the relations between hydrology and ecology. Since 1981, the principal investigator teaches a graduate class CIV E 634 "Surface-water Hydrology." The average number of students in the class is 10. One of the topics in the course syllabus is Hydroclimatology, which deals with the relation between hydrology and climate. The current plan is to develop a body of new knowledge to seamlessly integrate the treatment of ecohydrology and hydroclimatology into a coherent transdisciplinary treatment along the lines established by the pioneering work of Meinzer in his seminal 1927 work "Plants as indicators of groundwater." (U.S. Geological Service Water Supply Paper 577). The knowledge developed as a direct result of this sabbatical leave will be incorporated into the syllabus of the two graduate classes mentioned above. Eventually, a new graduate class entitled "Ecohydroclimatology" may be proposed, to continue to further develop the academic standing of this nascent field.