Addressing visitor capacity of parks and rivers: the debate on visitor capacity heats up, as the authors discuss a previous article on the topic.

As outdoor recreation researchers and academicians, each of whom has devoted a career to the issue of visitor capacity, we were interested to read our colleague Glenn Haas' essay in the September 2004 issue of Parks & Recreation. We agree with many of Haas' arguments, notably his suggestions that the National Park Service and other public agencies should give more attention to professional management of visitors, that recent judicial rulings may be a call for such attention, and that the call "'is as much a challenge ... to define what constitutes good planning, as it is to addressing visitor capacity."

As Haas suggests, it is imperative to articulate how to conduct visitor management planning well, and commit resources to accomplishing the task. Unfortunately, we believe that some of Haas' opinions and what we consider misinformation creates more confusion than clarity about how to do this.

With the insight gained from decades of research and conceptual thinking, most researchers and practitioners view visitor capacity as more than estimating how many people can use a park or river or, in Haas' words, "the prescribed supply of available recreation opportunities." We are convinced that to address visitor capacity, one must decide what conditions are acceptable, appropriate and desirable and prescribe actions to attain or sustain those conditions. Limiting use is only one of many techniques in the managers' toolbox. Many parks and rivers are best managed within their capacity by influencing the distribution and behavior of visitors. The number of visitors need not be limited and, therefore, estimating a numerical capacity does not contribute to improved management. Even where use limits are needed, estimating a numerical capacity is only a small part of the task of addressing capacity.

The article argues that a numerical visitor capacity is mandated by law. More critically, it states that it is worthwhile to concoct such numbers. We agree that numerical capacities are worthwhile where use levels exceed or are likely to approach capacity within the upcoming planning cycle. On rivers like the Colorado River in Grand Canyon, numerical capacities are critically important. The capacities in place there influence many important attributes, from biophysical conditions on the river to the economic viability of nearby communities.

However, in other places (probably the majority of public lands), use levels are currently only a small fraction of the amount of use that could be sustained. In such places, numerical estimates of the maximum number of people that an area can sustain will not lead to improved management. Moreover, these estimates will be wild guesses, likely to be off by orders of magnitude.

Numerical capacity will vary greatly depending on the entire suite of management actions that are implemented. To achieve a specific standard for acceptable resource impact, the capacity of a trail might be 10 times higher if the trail is paved than if it is not. It will vary with the success of Leave No Trace education programs, the types of use that are allowed, the frequency of maintenance and other variables.

On public lands where use levels are currently low and questions about trail paving and other management options have yet to emerge, planners cannot possibly concoct meaningful capacity estimates. Although we cannot predict how a judge might rule on this issue, we believe concluding that capacity is much higher than current use constitutes "dealing with or discussing the maximum number of people," even though a numerical capacity is not specified. It meets the "plain meaning rule" for the phrase "address ... user capacity:" More importantly, we believe it is wiser to make such a statement than to invest resources and potentially mislead people by making a wrong guess.

More disturbing than this difference of opinion is the article's attempt to advance arguments by spreading misinformation about management and planning frameworks, such as the Limits of Acceptable Change (LAC) and Visitor Experience and Resource Protection (VERP) processes. As members of teams that developed these processes, we note that Haas refers to them for the first time as "monitoring frameworks," rather than "planning frameworks for addressing issues of visitor capacity." The intent in development of these frameworks was to devise a process for addressing visitor capacity issues, including the articulation of numerical visitor capacities where appropriate. Monitoring is simply one step in the process. We should know because, with resource managers, we developed these processes.

Haas lists four "misunderstandings" that he attributes to these frameworks: (1) numeric capacity is not an important tool, (2) monitoring allows the circumvention of setting capacities, (3) monitoring allows the postponement of capacity decisions, and (4) capacity can be determined from monitoring, making a decision unnecessary. Anyone who has read the reports that describe LAC and VERP will know that the processes do not lead to any of these conclusions. Around the world there is a general consensus that these processes provide the best available means of developing visitor management programs and numerical capacities. Haas asserts that LAC and VERP are inadequate for developing numerical capacities, but does not explain why or offer specifics about alternatives. He states that because numeric capacity estimates are not a required output from LAC and VERP these processes cannot provide numeric estimates. Not so.

Haas states that proactive decisions about numeric capacity are needed. In contrast, we believe the real decisions that lead to both good visitor management and a numeric capacity are about objectives, indicators and standards, and the varied management actions needed to achieve those objectives and standards. These are the decisions that need to be made right now. These are the decisions at the core of the LAC and VERP processes. They are difficult decisions to make. We agree with Haas that difficult decisions should not be postponed or dispatched "to a future time and another person." But the article has it backwards when it says the important and hard decisions are about numeric capacities. The important and hard decisions--the ones that public land managers and planners need to give more attention to than they have in the past--concern defining objectives, indicators and standards. Once those decisions are made, numeric capacities are a logical outcome when they are needed.

Despite our disagreements with Haas and our concern about the misinformation contained in his writing, we believe he performs a service by reenergizing debate about the issue of visitor capacity. Progress in addressing visitor planning and management on public lands has been slow. However, we think that frameworks like LAC and VERP provide management agencies with the structure that is needed to make more progress. Hopefully, this debate will contribute to a brighter future for our parks, rivers and other public lands.

David Cole is a research biologist with Aldo Leopold Wilderness Research Institute, Missoula, Mont. Robert Manning is a professor at the School of Natural Resources, University of Vermont, Burlington, Vt. David Lime is a senior research associate, College of Natural Resources, University of Minnesota, St. Paul, Minn.