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SEI EIA Bulletin GUIDELINES FOR MONITORING AND DETECTING VISITOR IMPACTS Ecology In Action (EIA) is the technical bulletin of Sustainable Ecosystems Institute (SEI) Mission Statement SEI works to sustain ecosystems and the people who depend on them. We focus on areas of current or potential conflict and bring about cooperative solutions. SEI acknowledges the help and support of Oregon Sea Grant, California Sea Grant, the Bureau Of Land Management, Carl Halvorson, and Betsy Abbott, in the research and publication of this bulletin. GUIDELINES FOR MONITORING AND DETECTING VISITOR IMPACT 1 Set overall goals, and assemble team. 2. Gather baseline information identify plant and animal species present, including rare or threatened species identify potential indicator species identify key species and ecological interactions identify main habitat types identify other areas e.g. historical sites define concerns e.g. trampling, diver impacts etc. 3. Refine ecological goals, using baseline information. 4. Design the monitoring program. Monitoring will include: visitor numbers and activities, key species, sensitive species, indicator species, habitat area. Include volunteer, visitor, and community monitoring programs in addition to staff activities. 5. Set up monitoring sites in control and impacted areas (include representatives of main habitats). 6. Decide how data will be analyzed and interpreted. 7. Set thresholds for action. 8. Develop action plans to respond to impacts. Publicize these plans, and make visitors aware of them. 9. Continually evaluate monitoring and action plans to ensure that they meet the ecological goals. SEI visitor monitoring and detection guidelines 1994. © GUIDELINES FOR MONITORING AND DETECTING VISITOR IMPACTS Deborah. M. Brosnan, John Elliott, Timothy Grubba, and Ingri Quon. Sustainable Ecosystems Institute, 0605 SW Taylors Ferry Road, Portland Oregon 97219 USA. © SUMMARY Visitor impact is a major cause of concern in many parks and reserves. To preserve healthy ecosystems we need to be able to identify the nature and extent of visitor impact. Scientifically based monitoring and detection plans can form part of a management strategy that conserves fragile ecosystems, and allows for human recreation. This paper presents general guidelines for designing a monitoring plan. Main steps in developing a monitoring plan are: Set overall goals and establish a team to help develop a strategy; Gather information on key biological and ecological processes; Refine ecological goals; Design a monitoring plan; Set up areas to monitor in impacted and non-impacted (control) areas; Decide how data will be analyzed and interpreted; Set thresholds for action; Develop action plans to respond to impacts; Continually evaluate and update monitoring and management strategies. It is also important to include all users (especially traditional users), local community and business representatives, and conservation groups in any strategy. We recommend that monitoring plans be well publicized. This is so that the reasons for any required actions are clear, and are consequently more likely to be supported. Visitors and volunteers should be involved in monitoring programs. The final section of this paper is a series of replies to frequently asked questions. INTRODUCTION Human impact on natural ecosystems is seen as an increasing problem worldwide (e.g. US National Park Service 1992). How can we maintain healthy ecosystems and allow for recreational, educational and traditional use? At one time designating reserves or parks was seen as a way to protect unique ecosystems. Ironically, overuse is now destroying the very resource that reserves were set-up to protect. Closing-off vast areas of the natural environment is rarely a viable option. Neither is it altogether desirable. It is important that humans appreciate and respect nature; this can only be learned in a natural setting. How then can we balance the needs of a fragile environment and human needs? One approach is to re-evaluate the concept of a reserve or park. In the past, once a reserve had been designated, it was assumed that nature could take care of the biology. We now know that this is mistaken. Inadvertent human impact can often cause habitat destruction and species loss. A more enlightened approach is to monitor human impact in reserves, and to develop ecological goals, and actions plans. This general concept has many names, including determining carrying capacity, and limits of acceptable change. Whatever it is called, the basic message is the same: Ecosystems need monitoring and protection. What do we monitor? How can we detect human impact, and distinguish it from natural variability in species abundance? SEI is often asked these questions by reserve managers, and others interested groups. This paper answers these questions by providing information on how to monitor and detect human impacts in natural ecosystems. This report is a practical guide to the key points of monitoring and detecting visitor impacts. The details will vary somewhat, depending on the type of park and ecosystem (e.g. marine or terrestrial). This paper is not a management plan, but it is designed to be incorporated into an overall management plan for parks, reserves, or any frequently-visited natural area. Who should monitor? Anyone involved in managing a natural resource. This includes biologists and managers of parks and reserves. Anyone with responsibility in areas of ecotourism, including tour operators, and hotel owners who frequently bring visitors to the same areas. Local conservation groups or communities with an interest in protecting their resources. Ideally a monitoring program should be set up before opening a park or reserve to public use. However, even if a reserve has been operational for sometime, if there is no monitoring plan, then one should be developed and implemented. GENERAL GUIDELINES Set overall goals and establish a team. One of the first steps should be to set overall goals for the park or reserve. For instance, sustainability, and naturalness will be goals of most parks. Other goals might include, an ability of the ecosystem to recover to natural-like conditions; maintaining or increasing numbers of sensitive or threatened species; increasing the amount of key habitats. At this stage it is also important to identify the main concerns. Depending on the type of park these could include human trampling, diving, boat use etc. Once the overall goals have been determined, then set up a team to help implement these goals through a monitoring plan. This team should consist of, at minimum, managers who are responsible for the park or reserve, scientists (and other experts as required, e.g. cultural anthropologist), representatives from local conservation groups, and the community, representatives from businesses that use the resource (e.g. ecotour operators, hotel owners, dive operators, cruise ship industry). Particular attention should be given to the special needs of traditional users of reserves. The needs of these groups must be integrated into the overall monitoring and management goals. Local naturalists, and traditional users often have a wealth of information on historical changes, and natural history of species. This information can enhance the overall monitoring plan. Their knowledge should not be ignored. The important point is that all groups should feel that they have responsibility for the natural area. Gather baseline information This step is crucial to the monitoring plan. It is vital to understand the types of species and habitats that are included in the park/reserve. It is important to determine as far as possible if there are any key species or processes. This is the area where biologists and other experts are essential to good design. The following paragraphs include details of important biological and ecological processes to consider. Biological Information and Ecological Processes Keystone (Key) species: In many ecosystems there are keystone species (or key species), these are species that literally hold the ecosystem together by their interactions with other species. Without them the ecosystem would be very different. One example of a keystone species is the Sea Otter (e.g. Duggins 1980). Sea Otters feed on shellfish (abalone and sea-urchins). In turn shellfish eat seaweeds, particularly kelp. When sea otters are present, they keep shellfish in low numbers. Kelp grows and forms extensive kelp beds. Kelp beds are nursery grounds for many fish. They also provide a habitat for many invertebrates. In short they increase diversity in an area. When sea-otters are absent, shellfish increase in numbers. Kelp declines and the ecosystem consists of crustose corraline algae and urchins (urchin barrens). Key species are not always the large, obvious species in ecosystems. For example, fungi are key species in many forest ecosystems. Because of the great effect that key species have on ecosystems, it is important to try and identify any that are present in the ecosystem. If they are present, then particular attention must be given to monitoring these species. However, not all ecosystems have keystone species; instead many species interact to maintain diversity (e.g. Menge et al 1986). Indicator Species Are there species which are likely to be more susceptible to human impact. These species are ideal candidates to monitor for human impact (See Box 1). Indicator species have already been widely used to monitor impacts and ecosystem health. Strong interactions: In ecosystems some species have strong effects on each other. For example, some plants will not germinate unless another plant has first modified the soil (e.g. sand dune plants). Young and small corals often need sponges to hold them together until they have established themselves (Wulff and Buss 1979). Partners in such strong interactions are good indicators of ecosystem health. It is also important to maintain the partnerships between these species in balance. Sensitive Species: Some species are rare, and some are more prone to human disturbance. Sea turtles breed on many beaches in Caribbean Islands. It is important not to disturb nests or egg-laying females. Nesting birds (e.g. tems) may need special attention during their breeding season. Some of these sensitive species will be in the park seasonally (e.g. migrating birds). Such species will need to be identified and will need to be monitored and protected. Choice food species (e.g. shellfish) should also be carefully monitored. Reproductive patterns, dispersal abilities: Information on reproductive patterns and dispersal abilities of species is valuable. This will allow you to predict which species are likely to be able to recover from disturbances (natural and human induced). Natural Disturbances: It is important to have some understanding of the patterns of natural disturbances. For instance, are hurricanes common in the area? Are fires likely to occur? Are certain species more susceptible to damage from natural disturbances (e.g. large trees are more likely to be blown-over; similarly, finely branching corals are easily fragmented during hurricanes). This information will help in identifying habitats and species of concern, and areas to monitor. Case study I.- Indicator Species On the west coast of the United States, marine rocky shores are frequently used for recreation and education. Increased human use of these areas can be correlated with reductions in habitat and species. The shore at Yaquina Head Outstanding Natural Area in Oregon USA, was once considered one of the most biologically rich areas, and was consequently much visited by schools and colleges as well as tourists. This trend has continued. More than 400,000 users visit the shore annually, and often over 700 people can be on the shore at one time. (Note that visitors can only visit the shore during low tide and so this concentrates the effect.) The shore is managed by the Bureau of Land Management (BLM). BLM was concerned with the biological state of the shore, a concern echoed by many others. In 1992 a study was set up (Brosnan and Crumrine 1992) to investigate the effects of human impact, primarily trampling, on the shore. The study was set up in conjunction with studies in nearby pristine" areas. A human exclusion zone was set-up for six months, and changes in species composition and abundance monitored. Results of the study showed that the shore at Yaquina Head was lower in diversity compared to nearby "pristine areas". In addition key components of the ecosystem were missing- These included mussels (shellfish), and the large foliose seaweed species. Instead the area was dominated by low-growing seaweed "turf". When humans were excluded, many of the large foliose seaweeds returned, and diversity increased. However, mussels did not recruit; they will need many years to recover. Experimental studies in pristine areas showed that large foliose seaweeds and mussels are highly susceptible to trampling (Brosnan and Crumrine 1994). Mussels provide a habitat for over 300 associated species, and so the loss of mussels severely affects diversity and ecosystem health. Foliose seaweeds provide food and habitat for many other species, which are also lost. Similar impacts occur on shores in parts of Southern California (Elliott, Quon, and Brosnan; Zedier 1976). Mussels, foliose algae and algal turf are all potentially useful indicator species (see Brosnan 1993 for details on monitoring using the indicator species concept). In areas where trampling has little effect, mussels and foliose algae will thrive. However, when trampling is intense, diversity will be lower, mussels and foliose species are absent, and algal turf is the main species present. In these areas, an ecosystem dominated by algal turf is not a healthy ecosystem. Personnel with little biological background can be trained to monitor changes in these three types of indicator species. This technique can form the basis of a monitoring strategy. Monitoring and protection strategies are being used, and continually refined at Yaquina head. The staff (led by S. Gobat, BLM) continues to use results of scientific and cultural research to develop innovative management and conservation strategies. Habitat Types It is important to identify the main types of habitats, and how extensive each one is. It is also important to know how the habitat is distributed. For instance 30% of a park area may be sand dune. This could be one extensive dune area, or a collection of many separated smaller dunes. The distribution pattern will be important when you come to set ecological goals and monitoring criteria. Refine Ecological Goals Once you have established a base of biological information, ecological goals can be refined. Summarize available knowledge: By this time information should be available on: Number and distribution of different habitats. Important species and interactions. Likelihood of natural disturbances (e.g. fires, hurricanes). Current visitor rates and activities. However it is also most important to recognize what is not known. What are the limits to your knowledge, are there species, habitats, or key interactions which are poorly understood? You will not have all the information on the ecology of your park. The aim of the monitoring plan is to use the best information available (and it is important to spend time gathering and evaluating this). This will give you a firm basis for minimizing human impact. However, monitoring also teaches us more about how ecosystems function, and which are the key processes. It is a learning experience. At this point it may be appropriate to consider the types of activities in the park (based on potential environmental impacts). It may be useful to make decisions, or set new guidelines on issues, such as which activities will be allowed, where and when activities will be allowed, which areas will be open, and which will be off limits (seasonally or long term) to the public. Ecological goals are set, knowing that humans will have some impact on the ecosystem. For key species and habitats, biologists and the team will need to determine how much change is within biological limits of the system for recovery. For instance, some species are highly susceptible to foot-traffic, or diver impact. If these species are common over a wide area, then it may be decided that a reduction in abundance is acceptable in a particular area (open to public use), but other areas are then designated off-limits in order to maintain the species, and ensure that it can recolonize. At this stage goals should be quantitative and specific. For instance, clearly define the range of abundances that are "cause for concern" for each species or habitat. The Monitoring Program The basic biological information, and types of use allowed in the park will form the framework of the monitoring plan. Key points to include in the plan are: a. Monitor impacted (open to public use) and control areas (off limits). Control areas need to be large enough that they will not be affected by impacts elsewhere. Sometimes this can be difficult, for example feeding wildlife can impact all areas of the park by changing the behavior and numbers of animals. Ensure an adequate number of controls for each area, at least two are recommended (see Underwood, 1994). b. Pay particular attention to key species, sensitive species and rare species c. Include representative of all important habitats in control and impacted sites d. Monitor the probable causes of impacts. For instance, fishing effort, numbers of visitors etc. It is important to be able to correlate changes in human activity with impacts on the biology. e. Set up a monitoring program that is based on sound sampling techniques, and that is consistent. Sessile (attached) species such as plants, and corals are often monitored by "quadrat sampling" Quadrats consist of defined areas that are monitored consistently over time. The size of the quadrat will vary depending on the ecosystem. For instance, in marine rocky shore studies, quadrats often measure 0.5m by O.5m. These are either permanently marked areas, or random areas within study sites (e.g. within control or impacted plots (see Brosnan and Crumrine 1994)). In studies on reef-fish, quadrats are often larger and can be at least 5m x 5m. They are often permanently positioned (i.e. the exact same area within a study site is continually monitored). At each sampling period, data are collected from many quadrats within control and impacted sites. Numbers of individuals in the quadrat, or percent cover occupied by a species are ways in which abundance is estimated. For mobile species (e.g. fish, deer, or starfish,) counting numbers in quadrats is one method. Transects are another commonly used method (See Box 2). For some species it may be important to note size, age, Juveniles or adults), and gender. This will provide additional information on species health. If a species is thriving, then it should also be reproducing and there will be juveniles and adults present. However, if individuals are in poor health or stressed, then reproduction often fails. Because adults remain in the population for some time, you may not record a decline until it is too late (e.g. the decline of the marbled murrelet in the U.S.). The number of quadrats used in the monitoring program will depend on the habitat and size of the quadrat (1 0-20 are frequently used). Monitoring may need to be done seasonally, or even monthly. This will be determined by the types of species present, whether the ecosystem is degraded and recovery is in progress (more frequently), or whether the ecosystem is relatively stable (less frequent monitoring). Photographic and video records are always valuable, and should be encouraged as monitoring tools. NEED FOR SCIENTIFICALLY SOUND MONITORING The main goal of a monitoring program is to detect changes that result from human activities. This is not an easy task. It is natural for species abundance and composition to vary greatly (both temporally and spatially). The challenge for managers of parks and reserves is to recognize how much of the variation is due to human impact and how much is natural. Because the extent of natural variability in biological systems is so great, it is important to use sound scientific sampling procedures in any monitoring program. A well designed program will allow for greater confidence in the results and interpretations. This is vital, because without it, it will be difficult to justify unpopular management decisions, or to defend against legal challenges to management policies. Decisions based on inadequate data have often resulted in conflicts among different interest groups. In Case study 2: the British Butterfly Monitoring Scheme British naturalists were concerned, that previously abundant butterflies seemed less common. However, no-one had solid evidence for any decline, or could point to any particular cause. In the early 1970's, a small team of scientists developed a simple butterfly monitoring technique that is now in place at over 60 reserves in Britain. Monitoring is carried out by volunteer naturalists and reserve managers. The technique is simple. After first learning to identify butterfly species, volunteer observers walk a fixed transect route at a scheduled frequency. They record the numbers of butterflies seen on the various parts of the transect. A transect is a fixed route or direction. (The length varies depending on the study and ecosystem). In the butterfly monitoring program, observers walk their transacts at fixed times and in sunny weather (i.e. summer in Britain), as this is when butterflies are active. This makes for a consistently gathered data set. As a result trends are more easily observed and explained These results are used at two levels. At a national level, trends in the abundance of species over several years confirm a widespread decline in butterflies. Many of these declines have been closely related to habitat loss, and chemical use. For instance, many farmers have removed hedgerows (important butterfly habitats), and intensified pesticide use. Several butterfly species crashed in response. Results of the monitoring program have also been used to guide recovery and management techniques in parks and reserves. For example, in woodland reserves, changes in the mowing of paths have dramatically increased butterfly numbers. The British Butterfly Monitoring Scheme continues as a major success, and a welcome collaboration of scientists and volunteers. It is now being extended to other European countries. (S. P. Courtney). When designing a program the following factors should be considered: (For reviews and suggestions on statistical design and analysis for detecting human impacts see, Osenberg et al 1994; Underwood 1994; and Thrush et al 1994). Controls and impact areas. Ensure that controls are adequate, i.e. that they are comparable to impacted sites, and that there are sufficient control sites. Good controls help to eliminate alternative explanations of changes in abundance. Statistical rigor: Is there enough replication (among all habitats and species) to detect changes, and to relate these changes to anthropogenic factors? Have important factors been identified and isolated? Spatial and temporal considerations. Ensure that studies are carried out over sufficiently large spatial scales. Be able to recognize changes at a local level (individual sampling areas), and larger scale (e.g. entire habitat area or park). Initially, it will be difficult to interpret temporal trends in abundances, because many patterns will only become obvious with time. Ensure that monitoring programs are set up for long-term studies It is important to explain the need for consistent monitoring techniques to individuals who will carry out a monitoring program (staff and/or volunteers). Unless data are consistently and objectively collected, there will be little confidence in the results. Even more frustrating, if data are collected inconsistently (e.g. different techniques used, different species "lumped together” as a group), the data can often be useless. This is because it can be impossible to compare the data sets over time, and between control and impacted areas. When many individuals are involved in collecting information, this issue is often cause for concern. Managers should be aware of the dangers of inconsistency and take action to avoid it (e.g. training workshops). HOW WILL THE DATA BE ANALYZED AND INTERPRETED? Before starting to monitor, have a clear plan on how the data will be used and interpreted. This includes decisions such as, whether data will be entered on a computer data base, and if so which one (Are there programs already in use that it possible to tie into?). How will the data be entered? (rows and columns). These types of decisions often get overlooked because they seem simple. However, it can be very difficult to extract needed information from monitoring programs, when data have been poorly collected and compiled. Have a clear plan (preferable written) outlining how the data will be analyzed. What information will be compared? For instance, the monitoring plan might include a comparison on changes in abundance of sensitive butterfly fish between impacted and control areas every six months (for many years). Set up a database to make this comparison easy, and set it up to update information every six months. Interpretation of this comparison will depend on correlating it with changes in visitor use. Therefore it is important to collect data on numbers of divers, or boat activities, and to enter it in a database in a way that it can be combined with information butterfly fish. Set thresholds for action Success and sustainability are not easy. How can we define successful management? We need to define success in biological terms. If good background information has been used to set up a monitoring program, then defining success and points of concern will be easier. One way to define a healthy ecosystem is by species composition and abundance, presence of key interactions, and habitat persistence. Changes are a way of life, in ecological systems. But it is important to distinguish between natural changes, and effects of human impact, and to understand how these two types of changes interact to affect ecosystem health. Use historical records and biological information to set initial thresholds for action. For example, it may be natural for some species to show seasonal fluctuations in numbers, and these may tend to fall within certain limits. If numbers start to drop below natural limits, then this is probably cause for concern, and often indicates that some remedial action is necessary. For each habitat, keystone species, or sensitive species (as applicable), set a threshold level for action. Thresholds may include, a certain percent loss in cover of key coral, or tree species; reproductive failure of fish or bird species. Thresholds can be more effective if set conservatively. It is often the case that habitats have been much reduced (e.g. development) and this can limit a species ability to recover. Under these conditions, it may be prudent to set the threshold level within natural lower limits of abundance. Develop Action Plans Anticipate a worst case scenario. What will you do if bird reproduction fails continually, or if certain corals are disappearing at an alarming rate? Action Plans will need to include the possibility of declaring popular areas off limits for some time. Publicize monitoring and action plans. Keep people informed of your action plan. Let them know that you are caring for the ecosystem and that they need to expect closures if necessary. Keep a summary of your action plan available. Continued evaluation and refinement of monitoring and detection plans Base the monitoring and detection plans on the best available information and science. However, by monitoring we continually gain new information, and insights into the biological dynamics of parks or reserves. Plans should be evaluated regularly, on the basis of new information, to determine if they are still meeting the goals. For example, should certain species receive added attention? Have keystone species or sensitive species been identified? As more information accumulates, patterns, goals, and action plans can become more clearly defined. In addition, be prepared to revise your monitoring and detection plans as improved scientific techniques and methodologies become available. ROLE OF EXPERTS AND VOLUNTEERS Defining success and healthy ecosystems is critical. Trained ecologists and are most valuable here. It is easy to identify "habitat loss" or "reduction in species" as undesirable effects and causes for concern. But how much loss is too much? Where do we set the limits? Trained ecologists can use their expertise to set quantitative guidelines, that are based on the biology and ecology of the ecosystems concerned. For instance, the sea palm depends on regular wave-generated disturbances that extend over an area of l000 cm2 (Paine 1979). Smaller disturbances can drive it locally extinct. Developments that alter the pattern of wave action may result in species loss. Therefore we can use this information to quantify the amount of change (or level of dynamics in the system) that is too much, or not enough. Removal of starfish results in dominance by mussels, and the loss of plants and sessile invertebrates through competitive exclusion (Paine 1980). Competitive exclusion is a natural ecological process but it rarely occurs because starfish are present. Collecting these species will cause serious ecological imbalance and can drive many species extinct. Identifying and solving these problems in a quantitative way is the area to use the talents of biologists. They can help to define thresholds for action and success. A sound scientific basis to a monitoring and detecting plan will make it more likely to succeed. However, successful implementation of a monitoring and detection plan does not depend only on trained biologists. It is vital to include local naturalists, interested citizens and local groups in monitoring and detection. Many of these individuals have a local knowledge of the ecosystem that can contribute much to successful monitoring. It is preferable to use experts to help design a plan, and then to train staff and interested groups in monitoring techniques. Hold workshops and training sessions to explain the need for monitoring, and what is being monitored. Present a clear picture of the scientific rationale. Explain the need to be objective, and consistent, and the consequences of not following these guidelines. Include practical training in techniques of monitoring. Use a variety of different techniques (video, photographic, censuses of plant and animal numbers etc.) so that people with different talents and interests can become involved. Partnerships between science and concerned groups can have remarkable consequences for monitoring and conserving biodiversity. Make all groups part of the solution. QUESTIONS AND ANSWERS How can I distinguish between natural changes and human impact? This is the reason for setting up controls in your monitoring program. Controls are set up in visitor-free areas. If your monitoring shows that particular species are declining in visited areas, but not in control areas, then you have a good indication that visitor impact is the cause of the decline. This is why it is so important to have comparable monitoring sites in control and impacted areas. By contrast, if you find that species are doing poorly in all areas (control and impact) then the cause is likely to be something else. If could be some other form of human impact (e.g. pollution), or natural variability in the ecosystem e.g. an El Nino year, leading to poor reproduction or growth. Can volunteers really collect valuable scientific data? If volunteers are properly trained to collect data from monitoring sites, then volunteers can do an excellent job in collecting scientific data. The key is to provide good training. It is important that volunteers understand the scientific method behind monitoring, and the need for consistency and objectivity in collecting data. Well trained volunteers are often vital to research and monitoring programs. The Christmas Bird count in the US, and bird counts and butterfly monitoring in Europe, are carried out by volunteers (See Box 2). These are some of the best records that we have of bird and butterfly numbers. Results from these surveys have been instrumental in highlighting declines and changes in species numbers (e.g. current decline in Neotropical migrant birds in parts of the US). Our reserve has been suffering from overuse for a long time and is looking pretty bad, is it worth monitoring? Definitely yes, even if things are pretty bad, setting up a monitoring program is worthwhile for many reasons. First, monitoring will tell you if the situation is getting worse, or whether things seem to have stabilized.. Secondly if visitor numbers are increasing, monitoring will show you the effects of increasing use on the area. Thirdly if you decide to reduce the number of visitors to the reserve, monitoring will let you know if and how the ecosystem is recovering. Fourthly the information will be useful for developing a long term management plan for the reserve. And of course having hard evidence to show the effects of overuse always helps when unpopular management decisions need to be made. Humans always impact natural areas. Are you telling us that we need to close everything? No. Humans do impact the natural world as do many other species. However, our numbers are larger, and our impact is usually greater. It is necessary to maintain some pristine areas. These serve as control areas. They are also our safety net. Often pristine areas are the source of new colonists or individuals for degraded areas. It is also important that humans recognize their ties to biological diversity. (After all we are a part of that diversity.) We will always want to enjoy nature. So it is important that we have access. But we do need to ensure that we don't love nature to death. This may mean limiting numbers of visitors over a time period (for example, by using a reservation system, similar to that used by many campgrounds, or hotels). It may mean designating part of a reserve as off-limits. This does not mean that everything is closed. Sound management strategies need not overly interfere with our enjoyment of nature. They can ensure that the natural world is sustained for all to enjoy. What about education, does that help? Education is vital and should be an integral part of any management plan. Visitors should be encouraged to behave in ways that conserve the natural resource. This is best achieved by explaining how certain behaviors harm the resource, and how others protect it. Educating visitors should start before they reach the park or reserve. Information can be provided in hotels, cruise ships, campgrounds, restaurants, and by tour operators. The more types of media in use the better; written pamphlets, attractive signs, videos, table games, guided tours are all goods ways to get a conservation message across. Use as many of these as you can. Encourage visitors to become a part of the conservation team. This can be done by letting them record the numbers of butterflies, bird, corals, butterfly fish etc. that they see on a hike/ tour/ dive. This information can be turned into the park office when they are finished. Have information posted on the results of these informal surveys. If we close-off the most degraded areas of our park, can we predict how long it will take for complete recovery, and do we know that it will return to what it was before? Biological variation is a fact of life. No-one can predict exactly how fast recovery will take place, or exactly which species will return. Biologists can predict in general terms which species are likely to come back first, and whether some species need other species present before they can colonize (information in key biological/ecological interactions will help here). However, although recovery often follows a predictable sequence in many ecosystems, the length of time for recovery can vary quite a lot (from months to years for some ecosystems). Dispersal of spores and larvae, nutrients, water currents, wind and weather patterns can all affect the rate of recovery. Even if many of the species return some of them may -not be as abundant as they were before degradation; others may be more common. It may be possible to return to a healthy and functioning ecosystem, but it is unlikely that it will be exactly as it was before. ACKNOWLEDGMENTS We thank S. P. Courtney, and B. Haas for advice and assistance. Discussions, and visits with Steve Gobatt (BLM), Howard Overtone (Cabrillo National Monument), Caroline Rogers (VI National Park) helped to shape our ideas, but we accept full responsibility for the contents. We acknowledge the support of Oregon Sea Grant and California Sea Grant. REFERENCES AND ADDITIONAL READINGS Boo, E. 1991. Making Ecotourism sustainable: recommendations for planning, development and management. pp. 87-199. In Nature Tourism T. Whelan editor. Island Press. Brosnan, D. M. 1993. Human impact on marine communities: monitoring and management strategies. Recent Advances in Marine Science and Technology 1993 pp. 333-341. Brosnan, D. M. and L.L. Crumrine 1992 Human impact and a management plan for Yaquina Head Outstanding Natural Area. Report to Bureau of Land Management, Department of Interior, USA - 1994 Human impact on marine Communities Journal of Experimental Marine Biology and Ecology 177, 79-97. Duggins, D. 0. 1980 Kelp beds and sea otters: An experimental approach. Ecology 62, 447-453. Lucas, R. C. 1982. Recreation regulations-when are they needed? Journal of Forestry 80,148-151. Menge, B. A.. J. Lubchenco, L. Askenas, and F. Ramsey. 1986. Experimental separation of effects of consumers on sessile prey in the low zone of a rocky shore in the Bay of Panama: direct and indirect consequences of food web complexity. Journal of Experimental Marine Biology and Ecology 1 00, pp. 225-269. Osenberg, C. W., R. J. Schmitt, S. J. Holbrook, K. E. Abu-Saba, and A. R. Flegal. 1994. Detection of environmental impacts: natural variability. Ecological Applications 4, 16-30. Paine, R. T. 1979. Disaster, catastrophe and local persistence of the sea palm Postelsia palmaeformis. Science 205,685-687. Paine, R. T. 1980. Food webs: linkage, interaction strength and community infrastructure. Journal of Animal Ecology 49,667-685. Parsons, D. J. S. McLeod. 1980. Measuring impacts of wilderness use Par*s 5, 8-12. Thrush, S.F., R. D. Pridmore, and J. E. Hewift 1994. Impacts on soft sediment macrofauna: the effects of spatial variation on temporal trends. Ecological Applications 4, 31-4 1. Underwood, A. J. 1994. On beyond BACI: sampling designs that might reliably detect environmental disturbances Ecological Applications 4, 3-15. Wulff, J. L. and L. W. Buss 1979. Do sponges help hold coral reefs together? Nature 281, 474-475. Whelan, T. 1991. Nature Tourism Island Press. Zedler, J. 1978. Public Use in Cabrillo National Monument intertidal zone. Project Report of the U S. Dept. of the Interior National Park Service 52pp

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