1. Introduction to Springs Ecosystems

1. INTRODUCTION TO SPRINGS ECOSYSTEMS SPRINGS ECOLOGY AND STEWARDSHIP ers to improve understanding and management Although they are among the most biologi- of springs, and the potential for collaboration and cally and culturally important and highly threat- partnership. Our goal is to focus discussion on ened ecosystems on Earth, springs are poorly springs stewardship by sharing information and studied and inadequately protected (Stevens by presenting technological tools that support and Meretsky 2008). Most springs are relatively efforts to understand the complex ecology of small size, yet they support at least 16% of the springs. We also conduct research, training work- endangered animals in the United States, as well shops, and coordinate with other organizations, as untold thousands of rare or highly restricted agencies, Tribes, and researchers who are trying species. Emerging in many forms, springs are to locate, study, and protect these critical endan- windows into the Earth, and some of the most gered ecosystems. sensitive indicators of global climate change. CONCEPTUAL MODEL Springs are also sites of enormous cultural signif- Springs are ecosystems in which groundwa- icance to indigenous cultures. ter reaches the Earth’s surface through complex, Little research has been focused on springs sometimes lengthy, flow paths through subsur- ecosystems. Until recently there has been no sys- face structural, geochemical and geomorphic tematic effort or methodology for comprehensive eco-assessment. Although there have been recent efforts to develop a more consistent terminology, classification, and methodology, these have not yet been widely accepted. As a result, existing information is often minimal, fragmented and largely unavailable to researchers, land managers, and conservation organizations. Due to the lack of information and attention to these ecosystems, many springs have been lost through poor groundwater and land use practic- es, with estimates in some landscapes exceeding 90 percent. This loss of springs habitat constitutes a global environmental crisis. However, if the supporting aquifer is not impaired, springs ecosystems can be relatively easily and inexpensively rehabilitated or restored. The need for improved stewardship of springs is widely recognized, not only in arid regions but throughout the world. They are of concern to all who manage springs and care about stewardship of critical natural and cultural resources. The Springs Stewardship Institute works to Fig. 2–1. Lockwood Spring in Coconino National improve communications among springs manag- Forest, Northern Arizona. 7 environments. At their point of emergence, ecosystems and the imperiled state of their biota. the physical geomorphic template allows some However, human demands for water often pre- springs to support large arrays of aquatic, wet- clude their protection, and the complex, highly land and terrestrial species and assemblages, multi-disciplinary nature of springs research sometimes including cave and hyporheic biota. has retarded development of a comprehensive, Many springs serve as paleorefugia, and as long- conceptual approach to understanding springs as term stable habitats in which the evolutionary ecosystems. processes of natural selection, isolation, and We proposed a conceptual model of springs adaptation (sometimes to extreme environmen- ecosystems (Stevens and Springer 2004) and tal conditions) support restricted and endemic developed the general model from a suite of species. In ecological time-frames, small isolated dynamic ecosystem models, associated pro- springs in arid regions may be tremendously cess-component mechanistic models, and a productive, and may provide the only available state-and-transition framework of human im- water and habitat in the landscape for many pacts on springs ecosystems. Such an effort is plant and animal species. From a biogeographical important to ground inventory, assessment, perspective, springs often function as islands of stewardship activities, and monitoring. Until it is habitat, and may contain paleontological remains more fully quantified and tested, the model will that reveal much about changing climates and not provide much predictive capability, but it is ecosystem responses over time, particularly in needed to expose gaps in knowledge, uncertainty, arid regions. Although in temperate regions, the and previously unrecognized interrelationships differences between springs and the surround- among springs ecosystems processes and compo- ing uplands may appear to be subtle, studies of nents. When coupled with rigorous groundwater Silver Springs in Florida demonstrate the com- models, and with additional research, much new plex interplay between ground and surface water, insight into springs ecology is likely to emerge and aquatic-riparian linkages that characterize from this model. springs ecosystem ecology. Many springs emerge in freshwater or marine settings, and recent information on subaqueous springs demonstrates many parallels with those of subaerial springs, including high levels of biodiversity, species packing, productivity and endemism. Although poorly explored, arid lands springs often appear to function as keystone ecosystems, exerting a vastly disproportionate impact on adjacent ecosystems and regional ecology as compared to non-springs habitats. Several sym- posia and survey studies of springs have been conducted in the United States; however, springs ecosystem ecology remains rarely studied and poorly known. The scope of most previous work has been on a relatively small suite of physical characteristics of springs (e.g., flow and water quality), individual taxa or biota (e.g., Trichop- tera, aquatic snails, aquatic invertebrates, and springs biota in general), or on relatively restricted geographic areas. Virtually all studies conducted in recent decades have recognized the threatened ecological condition of springs 8 9 A KEY TO SPRINGS TYPES than 1,500 springs throughout the New World. While 13 primary springs types are described Overview here, note that nearly all types of springs can be To our knowledge, the first dichotomous created through anthropogenic action, or have key for springs classification was that of Bryan substantial anthropogenic attributes; springs (1919). He created a key to 26 springs types based in these situations would be labeled with the on aquifer and water source hydrology, bedrock subtype “anthropogenic.” Common examples geology, and geologic structure. While influ- of anthropogenic springs range from livestock encing groundwater emergence, those charac- tanks, springs altered by diverting or piping flow teristics, are not, in themselves, springs-specific from the original source, springboxes that have and broadly overlap among geomorphological- obliterated the natural source, and hot springs ly-classified springs types. While Meinzer (1923), resorts. This key has been tested by colleagues Alfaro and Wallace (1994), Springer et al. (2008), and associates, both those familiar and unfamil- and Glazier (2009), described in detail the vari- iar with springs inventory classification. ation in aquifer geology, flow, water temperature and geochemistry, vegetation, and other factors, they did not attempt to assemble those data in such a fashion as to clearly distinguish types. The primary advantage of a springs classification system based on differentiation of emergence geomorphology is that springs type strongly influences ecosystem function and species assemblages. Thus, individual springs types are suscep- tible to different kinds of stressors and threats and require type-specific management actions. The geologic approach advanced by Springer and Stevens (2009) and Stevens et al. (in review) is recommended to facilitate integrated information management and assessment. In addition, a geomorphic approach readily lends itself to development of a dichotomous key, so that technicians can quickly document springs type. Below we present a dichotomous key and illustrated description to the geomorphic terrestrial springs types identified by Springer and Stevens (2009) and refined by Stevens et al. (in review; Table 4-2). This classification also includes paleosprings, two types of hillslope springs (upland and floodplain), as well as three types of mound springs (carbonate, organic, and ice). Thus, some of Springer and Stevens (2009) springs types have been expanded to encompass commonly found divisions among previously identified springs types. Fig. 2–2. Even Spring, is a previously unmapped The springs types described in the key (Table spring in the Gila Wilderness. Many springs are 4-2) are based on revision of the Springer and missing from databases and topographic maps, Stevens (2009) classification system. The dichoto- leaving land managers with insufficient information to understand and protect these important mous key was developed by examination of more resources. 10 Table 2–1. A dichotomous key to terrestrial springs types (Stevens et al. in review). Springs types are derived from Springer and Stevens (2009), but also include paleocrenes, floodplain vs.upland hillslope springs, and three mound-form springs subtypes added to their classification. No. Alternative Springs Type 1 Groundwater expression of flow emerges or emerged within a cave (a Cave water passage through basalt or other volcanic rock, or limestone), before flowing or emerging into the atmosphere Groundwater expression of flow emerges or emerged in a subaerial setting

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