Classification of Lentic Riparian Areas: Challenges and Opportunities Linda Vance Montana Natural Heritage Program University of Montana SRM Lentic Symposium Billings, MT February 9,2011 Goals of the presentation Introduce the concept of wetland classification and its benefits Discuss the various classification systems in effect and under development Evaluate strengths and weaknesses of major systems Assess potential for crosswalking across systems Lentic vs. Lotic Wetlands Lentic riparian wetlands: are associated with still water systems. occur in basins, on slopes or on flats lack a defined channel and floodplain. Lotic riparian wetlands are associated with running water systems contain a defined channel and floodplain. have am open-conduit channel carrying flowing water and dissolved and suspended material. We’re done, right? No: defining wetlands is not the same as classifying them. Why classify? Inventory and mapping Assessment Monitoring Management Inventory and mapping Classifying wetlands into discrete types allows us to track change over time, and to identify trends that may only affect specific types of wetlands Example: USFWS Status and Trends measures changes in acreage by wetland class Assessment Wetlands are typically assessed in relation to a “reference standard” representing minimally disturbed, least disturbed, or best available condition. Requires ability to distinguish between attributes that result from different geographic or environmental drivers or those that have been brought about by human disturbance Monitoring By classifying wetlands into similar types, it is easier to track the impacts of environmental variables such as drought or to predict return intervals for processes like fire Classification also helps predict transitions, expected restoration pathways, and community composition, so that natural change over time can be distinguished from anthropogenic change Management Classifying wetlands into discrete types helps managers by identifying specific responses to management actions, susceptibility to invasives, sensitivity to disturbance, etc. Great idea, let’s do it…. Multiple classification systems already in effect and in development across the country Three main kinds of classification: Structurally-based, generally not regionally specific Structure and geography- based, emphasizing regional groupings Geography-based with strict boundaries Classification based on structure: Cowardin Cowardin classification is best Landform: Palustrine, known Lacustrine, Riverine Designed to facilitate mapping Vegetation/Habitat: Forested, emergent, shrub-scrub, aquatic bed Directed at waterfowl management efforts: describes water and food availability Water regime: Seasonally flooded, permanently flooded, saturated, etc Widely used as a result of National Wetlands Inventory Hydrogeomorphic modifiers: Excavated, ditched, diked, Consistent across the country impounded PALUSTRINE AQUATIC BED PERMANENTLY FLOODED PALUSTRINE EMERGENT SEMI-PERMANENTLY FLOODED PALUSTRINE SHRUB-SCRUB SEASONALLY FLOODED Fact that this is in the Middle Rockies is irrelevant for classification purposes Classification based on structure: HGM Hydrogeomorphic method is used Geomorphic: lacustrine fringe, by the ACOE and many state tidal fringe, slope, mineral flats, transportation and water quality organic flats, depressional, agencies riverine The HGM emphasizes the Water source: precipitation, functions that particular classes of groundwater, surface flow wetlands provide, e.g., flood attentuation, ground water Hydrodynamics: direction and recharge, sediment capture, strength of flow nutrient cycling, steam flow maintenance, aquatic habitat, etc. It is especially useful in permitting and mitigation contexts GEOMORPHOLOGY: DEPRESSIONAL WATER SOURCE: SURFACE HYDRODYNAMICS: THROUGHFLOW Regional handbooks have been developed to provide further guidance to classification, e.g., for prairie potholes, wet pine flats in the Atlantic coast, rainwater basin depressional wetlands in Nebraska…..but again, emphasis on geomorphology rather than vegetation Classification based on structure and geography: GAP/Landfire Recurring groups of biological Level 1: Lifeform (Forest, communities in similar physical Grassland, Sparse and Barren) environments that are influenced by similar dynamic Level 2: Climatic and ecological processes, like fire elevational gradients (e.g., or flooding alpine grassland, montane 551 ecological systems and 39 grassland) land use classes at the national level Level 3: Geographic gradients, Designed for use with e.g., “Northern Rocky predictive distribution models Mountain Conifer Swamp” but of wildlife species and for “Intermountain Basin predicting fire intervals and Greasewood Flat”” severity NORTH AMERICAN ARID WEST EMERGENT MARSH Ecological systems are linked to the National Vegetation Classification Standard, and detailed information on dynamics, structure, composition and (in some cases) restoration and management is available through Natureserve and Heritage programs Classification based on structure and geography: The National Vegetation Classification Standard There are 8 classification levels based on 5 criteria: Level 1 Formation Class Diagnostic growth forms Level 2 Formation Subclass Dominant growth forms Compositional similarity Level 3 Formation Diagnostic species Dominant species Level 4 Division Biogeographic criteria enter at Level 5 Macrogroup Level 4, e.g., Level 6 Group Division: North American wet Meadow, Riparian and Marsh Macrogroup: Great Plains Freshwater Wet Meadow, Level 7 Association Riparian and Marsh Group: Great Plains Prairie Level 8 Alliance Pothole Classification based on defined biogeographic boundaries: Ecological sites Interagency effort to define common units for inventory, monitoring and analysis Depends on defined biogeographic boundaries established through expert knowledge or analysis (MLRAs, LTAs) Includes climate features, soil features, ecological dynamics; includes state & transition models, and wildlife habitat elements and vegetation Ecological s ECOLOGICAL SITE CHARACTERISTICS ECOLOGICAL SITE CHARACTERISTICS Site Type: Rangeland Site Type: Rangeland Site Name: Draft Wet Meadow (WM) RRUSite 46- CName: 15-19" p.z.Draft Wet Meadow (WM) RRU 46- / / Carex rostrata - Carex aquatilis var. aquatilisC 15-19" p.z. ( / / beaked sedge - water sedge) Site ID: R046XC518MT (Carex rostrata - Carex aquatilis var. aquatilis Major Land Resource Area: 046-Northern( beaked Rocky Mountain sedge Foothills - water sedge) Site ID: R046XC518MT Major Land Resource Area: 046-Northern Rocky Mountain Foothills Strengths and weaknesses MAPPING INVENTORY ASSESSMENT MONITORING MANAGEMENT NWI Strong Strong Weak Weak Weak HGM Strong-weak Strong * Strong Moderate Moderate LF/GAP Strong Depends Moderate** Strong Moderate-weak NVC Depends Depends Depends Depends Depends ESD Weak Depends Strong Strong Strong Crosswalks allow for effective information mining Palustrine Aquatic bed/ Palustrine emergent, semi-permanently flooded Depressional, surface water through-flow Arid West Emergent Marsh Typha latifolia western herbaceous vegetation No ESD (not rangeland) Take home messages Classification systems are vexing, but classification is vital to many monitoring and management activities Range professionals with an interest in wetlands need to familiarize themselves with the classification systems and their uses MORE INFO: www.mtnhp.org.