Item 8 of the CROGEE Read-ahead

Executive Summary

The C&SF Restudy's Alternative Evaluation Team has created a working definition of "restoration," and described the rationale used by the AET for creating this definition. At broad regional scales, the AET is in agreement on the definition and characteristics of a restored natural system in south Florida. At more specific, finer scales, a consensus definition is still emerging as the team continues to develop additional biological performance measures and targets. As a basis for ultimately determining the hydrological patterns which achieve the biological targets, the restoration program must substantially shift the natural system in the direction of NSM-like patterns. It is generally accepted that, although complete hydrological restoration is not possible in the remaining natural system, a successful restoration of the biological targets defined by the performance measures is entirely possible.

Introduction

This "White Paper" presents the Alternative Evaluation Team's working definition of "ecosystem restoration," and describes the rationale used by the AET to create this definition. The members of the AET and the Restudy Team want to reiterate that at broad regional scales we share a common view of how we define successful restoration. We also recognize that there are scales at which our views differ. We tend to agree on the general characteristics of a restored south Florida ecosystem. The members of the team may differ as to which characteristics are most important, how best to represent them in hydrologic models, and how close to the conceptual targets we must be to declare that restoration has been achieved. None of these varying points of view lessen our common belief that restoration of the south Florida ecosystem is our shared goal, and that it is a goal that can be defined and measured.

Some differences of professional opinion have characterized each step in the evolution of the C&SF Restudy and indicate a healthy diversity in backgrounds and agendas. In many cases, we may lack the amount of scientific information we would prefer to have to make completely risk-free decisions and predictions. In other cases, differences of opinion seem to be based on differences in emphasis among the resource agencies, which are reflected in the viewpoints of the technical staffs from each of these agencies. For example, in the Everglades basin, subregional differences in emphasis resulted in the creation of two sets of performance measures, one for north of the Tamiami Trail and another for south of the Trail. These two set of performance measures are not consistent in their adherence to NSM-based targets because of differences in the nature of the major ecological issues on the two sides of the Trail.

These varying professional opinions have been the source for a range of views and perspectives for defining a restored natural system in south Florida. Yet, to evaluate the performance of the Recommended Plan, and to achieve a team consensus in our views of this plan, we need to apply a consistent set of standards based on a common view of restoration. For this reason, the AET Everglades Basin task team, at its workshop on I September, 1998, highly recommended we produce a written statement fully expressing the AET's definition of "restoration", one that reflects the team's current thinking. The following "White Paper" presents a new, improved AET definition of ecological restoration, and discusses several important philosophical and technical considerations that guided the team in the development of this definition.

The need to re-address this topic at this time was prompted by assessments of the Recommended Plan, which suggested that the plan, "is not there yet." This statement raises the question of what is "there" in terms of restoration? By agreeing upon a benchmark definition of restoration, the AET can then design consistent performance measures and use them to evaluate future refinements to the Recommended Plan. In this white paper, terms such as "natural system" and "ecosystem" are used interchangeably; both refer to the natural, wetland systems of south Florida. This white paper will undoubtedly go through periodic revisions. Future versions will be identifiable by changes in the title (e.g., Restoration - 111, etc.) and date.

Considerations for Defining Restoration

Definitions of restoration have abounded in south Florida over the years. A comprehensive, AET approved definition of restoration should, in some way, combine the ideas of the team with the major ideas from these earlier efforts to define a restored Everglades. Good regional scale definitions of ecological restoration in south Florida have been provided in a number of recent reports and publications. These include Science Subgroup (1993), the C&SF Restudy Reconnaissance Report (1994), Davis & Ogden (1994), and most recently, the draft Fish and Wildlife Service CAR for the Restudy Recommended Plan (1998; chapter 2).

Because broad scale definitions like those mentioned above are often too general and too all-inclusive to be of practical use as a basis for developing specific, measurable restoration targets, Conceptual Ecological Models have been created to guide the AET in the development of performance measures and restoration targets. These Conceptual Models meld the most widely accepted hypotheses for explaining the ecological effects of anthropogenic stressors; on natural wetland systems in south Florida into a "picture" of the major cause and effect linkages in these altered systems. Each model identifies the major anthropogenic stressors, and the best ecological indicators of the effects from these stressors. It. is assumed that a full set of performance measures and targets based on the stressors and attributes (indicators) in the Conceptual Models will provide sufficient spatial, temporal and hierarchical coverage of the natural systems that they ultimately will provide a framework for a more detailed and comprehensive definition of restoration.

Thus far, most performance measures used by the AET during the plan formulation and evaluation phase of the Restudy have been based on the hydrological stressors in the Conceptual Ecological Models. The logic is that positive ecological responses will occur only once the problems caused by the stressors have been moderated or removed. The process of developing additional performance measures from the Conceptual Models is not complete, which explains why consensus has yet to be reached on the final set of ecological performance measures and restoration targets. Additional performance measures based on the set of ecological attributes in the models will be developed. Creation of these attribute-based targets will go a long way towards building consensus 'for a set of biological measures for characterizing (i.e., defining) a restored ecosystem.

The AET members agree that, although a parsimonious set of performance measures and targets is necessary for planning and evaluation purposes, a regionally restored ecosystem will ultimately be defined in more comprehensive terms than is possible by merely summing the individual targets described by the performance measures. This is because the performance measure targets, if correctly selected, are only representative indicators of total system responses. Even an expanded and refined set of performance measures cannot fully address the entire range of desired system responses. This is especially the case with the current, initial set of measures. This initial set focuses on correcting the major hydrological stressors in the natural system, and incompletely addresses restoration targets for the ecological attributes defined by the Conceptual Models. However, as the total package of performance measures becomes more ecologically comprehensive, the combination of targets established by these measures, in effect, increasingly defines the desired characteristics of a restored system.

Until such time as performance measure targets are established for the full suite of ecological attributes in the Conceptual Models, AET members likely will continue to hold a range of views and to identify different endpoints in their characterizations of a restored natural system. Opinions on how best to characterize a restored natural system, expressed during the 01 September 1998 Everglades Basin workshop, were tabulated in the AET workshop memo of 21 September 1998. These opinions, combined with earlier definitions, demonstrate the spatial and hierarchical scales at which current opinion will allow for consensus on a definition of restoration.

A Restoration Definition

Restoration can be defined at two different scales, (1) by defining the word restoration" at a more conceptual scale within the context of existing south Florida wetland systems, and (2) by defining the physical and ecological features which should characterize the "restored" wetland systems of south Florida. A good working conceptual definition has previously been suggested by the SERA Natural Systems Team (Ogden, Davis & Gulick 1997), and endorsed by the Total Systems Team of the AET (L. Manners, pers. comm.). This definition is as follows. "In its original meaning, and when used with reference to a natural systems under anthropogenic stress, 'restoration' means a return to a system that is not under anthropogenic stress. When used in the context of the south Florida wetland system, 'restoration' has come to mean the recovery of sustainable wetland systems at some higher level of ecological health than characterizes the current, impacted systems. The broad goal is to recover and sustain the major defining ecological characteristics of the pre-drainage south Florida wetland systems over as large an area of the remaining wetlands as possible." This conceptual definition is consistent with the view that restoration can be successfully achieved without a full return to pre-drainage conditions.

The points of views expressed at the 0 1 September AET workshop on how to go about characterizing the ecological features of a restored natural system (definition 2), reflect legitimate differences of professional opinion as to where the emphasis should be placed in characterizing a restored ecosystem, and which ecological problems are the most important to resolve. However, all of these views appear to be consistent with a widely accepted definition of a regionally restored ecosystem, underlining the degree of consensus on the broad definition of restoration. The team consistently sees the goal of the south Florida restoration project to be to recover a sustainable, self-regulating and self-organizing ecosystem, by restoring to the extent possible the biological and physical characteristics that defined the pre-drainage wetlands of south Florida. The biological and physical characteristics which define a restored system include the recovery of (1) low nutrient levels in marshes, (2) healthy plant community mosaics, (3) strong food chains at middle tropic levels, (4) viable populations of animals with large spatial requirements, (5) an abundance of certain upper tropic animals, (6) the recovery of endangered species, (7) extensive low salinity estuaries, (8) large spatial extent, and (9) dynamic water storage and sheet flow. In qualitative terms, all members of the AET agree that these elements must be included in any successfully restored greater Everglades ecosystem.

This broadly stated definition reflects the ecosystem scale at which there is full agreement as to how to characterize a restored wetland system in south Florida. It is anticipated that as more attribute-based performance measures are created, as the understandings of ecological processes and relationships in the greater Everglade basin continue to improve, and as the accuracy of our evaluation tools improve, our definitions will increasingly become expressed at finer scales.

Confounding Factors

It needs to be pointed out that full restoration requires much more than the implementation of a strong hydropattern restoration program. Ecological restoration cannot even begin to succeed without the successful maintenance or recovery of a number of other conditions, such as: an appropriate fire regime, exotic control, good water quality, and appropriate human use of different parts of the system. A restored system will also require the physical connections among areas of the system to allow for the completion of all parts of organism's life cycles and to provide for flexibility in their movements about the system to deal with temporal variations in water levels, fire history, and climatic events.

The AET recognizes that there will continue to be uncertainties associated with our current understandings of natural responses, which will continue to influence our ability to reach a final definition of a restored system. The present natural system is substantially and irreversibly altered from the pre-drainage system. Current levels of understanding of ecological relationships foster a significant degree of uncertainty in predictions of ecological responses. Characterizations of ecological responses to specific hydrological measures should, for the most part, be viewed as hypotheses to be reviewed and tested over time during implementation of the plan. Certainly, at this point, any predicted level of hydrological performance can not automatically be equated to a similar level of ecological performance.

It is generally agreed that the original pre-drainage wetland systems in south Florida can not be fully "restored", in the sense of the original meaning of the word. h-reversible losses in spatial extent, the ecologically and hydrologically artificial boundaries of the remaining natural systems, losses of several feet of organic soils over much of the remaining sloughs, extensive invasions of exotic plants and animals, changes in soil, and water chemistry, and sea level rise are among the factors that prevent a theoretical restoration from actually occurring. The realistic goal is to shift the ecological health of the current, degraded system far enough in the direction of the ecological conditions that existed in the hypothesized pre-drainage system, to recover those ecological features which characterized a much healthier system. The largest uncertainty associated with this strategy is that we can not know, with existing information and simulation models, the exact hydrological pattern that will achieve any specific set of ecological improvements that exist along a spectrum of potential improvements that can occur as the system shifts in the direction of the pre-drainage system.

This situation calls for a different way of thinking about restoration, that it is as much a process and an opportunity as it is a set of endpoints. We will learn much about these systems from measuring actual responses as the restoration program is implemented.

This perspective, "...argues strongly that restoration must be viewed as an open-ended process rather than as having a discrete goal (Davis & Ogden 1994)." Restoration as a process must be adaptive, in that regional visions must be incrementally implemented and evaluated. "Because of the changing conditions [e.g., sea level rise] and uncertainties, ecosystem stability can only be viewed as a short-term goal. Long-term restoration must be an on-going process whereby restoration implementation becomes a continuing series of management decisions. Each decision should be based upon a growing pool of research information, updated measurements of ecosystem responses [especially of more long-term responses and cycles], and evaluations of degrees of progress in reaching a set of goals or targets that have been identified as indicative of ecosystem vitality."

Thus the inclusion of a specific, workable adaptive assessment process is an essential element in an evolving definition of ecosystem restoration. Through this process we will come to a consensus regarding the kind of natural system we ultimately should be striving to recover, and the hydrological patterns that are most likely to get us there.

How close must we get?

We can not state with certainty what ranges of conditions for each of the major hydrological parameters will produce the strongest ecological recovery. Almost certainly, a successfully restored system can operate within a range of hydrological conditions, at unknown distances surrounding mean, NSM predicted values. These uncertainties exist because of legitimate differences of opinion about how complex networks of ecological parameters will respond to a range of regional improvements in hydrological patterns. Yet all AET participants agree that while hydrological restoration is not ecological restoration, it is the cornerstone upon which to build ecological restoration. The questions still being debated are ones of preciseness of model predictions, and scales and ranges of optimum hydrological patterns. For example, how close to the NSM-predicted conditions do actual hydrological improvements have to be in order to achieve desired ecological targets? And, in an irreversibly altered natural system such as the remaining Everglades, what is the combination of hydrological patterns and the ranges of conditions for each hydrological parameter that will improve and sustain certain ecological functions and relationships, and maximize the recovery of indicator plants and animals?

When we set a specific hydrological target, and modeling predicts that a plan does not meet that target, we are correct in stating that the plan "is not there yet," at least for that specific hydrological target. But what we cannot answer with nearly as much certainty with current ecological models is how well that plan, with its mixture of fully met and incompletely met hydrological targets, in a substantially altered natural system, achieves the broad ecological restoration goal stated above. In other words, we are not able to be as certain at this point in the planning process that a plan is either "there" or "not there" in meeting the regional ecological goals, especially when many of the hydrological targets are closely met. Realistically, further improvements in the Recommended Plan, for meeting the regional ecological goals, will come through the development of refined and more comprehensive ecological performance measures, improved ecological models, from optimization modeling during detailed design studies, and, perhaps most importantly, during an adaptive assessment process driven by empirical measures of ecological responses.

Item 8 of the CROGEE Read-ahead