Size Of Buffer Zone Research Articles

Diffuse Load Abatement with Biodiversity Co-Benefits: The Optimal Rotation Age and Buffer Zone Size

This article analyzes the optimal rotation age and the size of the buffer zone when society values harvest revenue, water quality, and biodiversity. In a theoretical model, we extend the traditional Faustmann rotation model to include the possibility of leaving an unharvested riparian buffer zone between the clearcut area and the watercourse to reduce nutrient load damages to the watercourse and increase biodiversity benefits in the buffer zone. We then analyze how the optimal rotation age and the optimal size of the buffer zone are chosen simultaneously. In an empirical analysis, we use Finnish data including simulation results of nitrogen loads to find the socially optimal solution with a numerical model. Biodiversity is valuated as a willingness to pay for retention trees left in the buffer zone. According to the empirical results, in the social optimum it is not optimal to allocate any land to an unharvested buffer zone when we consider the reduction of the nitrogen load as the only benefit provided by the buffer zone. However, when we add the biodiversity benefits into the empirical analysis, the optimal size of the buffer zone is 4% of the area in the social optimum.

The impact of buffer zone size and management on illegal extraction, park protection, and enforcement

Many protected areas or parks in developing countries have buffer zones at their boundaries to achieve the dual goals of protecting park resources and providing resource benefits to neighbouring people. Despite the prevalence of these zoning policies, few behavioural models of people's buffer zone use inform the sizing and management of those zones. This paper uses a spatially explicit resource extraction model to examine the impact of buffer zone size and management on extraction by local people, both legal and illegal, and the impact of that extraction on forest quality in the park's core and buffer zone. The results demonstrate trade-offs between the level of enforcement, the size of a buffer zone, and the amount of illegal extraction in the park; and describe implications for “enrichment” of buffer zones and evaluating patterns of forest degradation.

Biodiversity protection and economics in long term boreal forest management — A detailed case for the valuation of protection measures

Increased protection of forest biodiversity implies reduced income from timber production both for society and forest owners, and consistent analysis of the relationships between biodiversity benefits and corresponding costs is important both for forest managers as well as policy makers. Using a complex dynamic forest optimization model, we analyse impacts on economy and biodiversity of forest management restrictions implemented to protect biodiversity. A reference scenario is compared to two preservation regimes based on 1) the current Norwegian forest certification system and 2) an expert judgement designed to put strong emphasis on biodiversity protection in boreal forests. Economic impacts are expressed as net present value and harvesting level, while impacts on forest structure are expressed by a vector of variables including old forest proportions, growing stock, number of retention trees, size of buffer zones and amount of dead wood. A rather detailed description of forest structure and biodiversity measures represents the main improvements compared to previous analyses. Different restrictions result in 10–45% decrease in economic value of the forest compared to no restrictions. The most costly measures are found to be 50% increased rotation and keeping old-growth proportions higher than 20%.

Place a moratorium on the passage of sex offender residence restriction laws

D uring the past few decades, lawmakers have devoted increasing attention to policies aimed at managing sex offenders released to the community. Indeed, since 1994, all 50 states have enacted at least two pieces of legislation specific to sex offenders; at the minimum, each of the 50 states has established a sex offender registry and a community notification system in compliance with the Jacob Wetterling Act of 1994 and Megan’s Law of 1996, respectively (CSOM, 2008). Since this time, states have passed several other laws targeted at sex offenders. For example, some states require sex offenders to carry special identification cards, whereas other states have the authority to impose chemical castration (Mancini, 2009). Among the newest wave of sex offender policies to sweep the United States are residence restrictions. A recent analysis revealed that since 1999 more than half of all states have enacted a residence restriction law (Mancini, 2009). Residence restrictions come in different shapes (i.e., different “hot-spot” locations) and sizes (i.e., different “buffer zones”). A hot spot is a specific location that is restricted for sex offenders, and it typically is defined as a park, playground, daycare center, or school. A buffer zone is the exclusion perimeter that is established around identified hot spots. For example, a buffer zone of 500 feet means that sex offenders cannot reside within 500 feet of hot spots. Buffer zones can range from 500 feet to more than 5,000 feet depending on the state of interest (Mancini, 2009; Meloy, Miller, and Curtis, 2008). Despite variation in the scope of hot spots that can be included and the size of buffer zones that can be used, all residence restriction laws operate on the following underlying rationale: keeping a sex offender away from areas where children are

Overview of “The policy implications of residence restrictions on sex offender housing in Upstate NY”

Research Summary Only a handful of studies have evaluated how residence restrictions would affect sex offender housing options, and even fewer have compared different residence restrictions to one another. This study analyzed how different types of statewide residence restrictions would affect the housing options of convicted sex offenders in the Upstate New York region. Combinations of five buffer zone sizes (500 – 2,500 feet) and three scopes of restricted locations resulted in comparisons between fifteen unique residence restriction policies. Neighborhoods (i.e., census block groups) were first separated into three groups based on the percentage of restricted housing parcels they contained under each residence restriction policy (i.e., less than 33 percent of restricted housing parcels for the least restricted group, between 33 and 66 percent for the moderately restricted group, and more than 66 percent for the most restricted group). Measures of housing density, housing availability and housing affordability, and social disorganization were compared between these groups using ANOVA. Findings indicate that the least restricted neighborhoods were consistently the least dense and the least socially disorganized. However, the size and scope of a restriction influenced conclusions about the availability and affordability of housing and the overall number of neighborhoods offering substantial unrestricted housing to sex offenders. Additionally, comparing the extremely unrestricted and extremely restricted neighborhoods (i.e., neighborhoods containing less than 10 percent and more than 90 percent of restricted housing parcels, respectively) yielded similar conclusions to the comparisons of the least and most restricted neighborhoods. Policy Implications This study is important because it provides recommendations for best practices for evaluating potential or existing sex offender residence restriction policies in the future, as well as providing policy makers with evidence-based research to base policy decisions from. Some of the best practices promoted by this study include examining neighborhoods at the census block group level, using factor analysis for measuring social disorganization, and controlling for differing housing markets across the study area. In terms of evidence-based research results, this study found that how a residence restriction policy affects sex offender housing options at the neighborhood level can depend largely on the size and scope of the policy in question, but the neighborhoods likely to be the most restricted are typically the most dense, the most disorganized, and offer the most available and affordable housing options. As a result, policy makers should consider both the potential benefits of these policies, such as limiting sex offenders from residing in the most disorganized neighborhoods, and the potential consequences, such as limiting available and affordable housing options, or forcing offenders into only a handful of rural neighborhoods that may lack adequate support structures. Policy makers are advised to carefully study proposed or existing residence restrictions to ensure the evidence-based implementation (or retraction) of such policies. The results of this study indicate that residence restrictions, particularly in Upstate New York, are unlikely to be effective at either promoting the rehabilitation of registered sex offenders or increasing the safety of community members, particularly in less urban areas. As such, when policy makers are unable to devote the resources required to carefully study the effects of a proposed restriction, the results of this study suggest that residence restrictions should be bypassed in favor of other, more evidence-supported policies. Residence restrictions should not be used by policy makers who are seeking a “quick fix” to the problems of increased sex crimes or concerns about increased sex offender reentry. In order to be effective, alternative policies should have research evidence supporting their ability to (a) increase the ability of communities to informally monitor and control other neighborhood residents (see Walker, et al., 2001), (b) increase the supervision and treatment of such offenders (Walker, 2007), and/or (c) increase other opportunities that provide for the successful reentry and rehabilitation of convicted sex offenders.

Effect of lateral boundary scheme on the simulation of tropical cyclone track in regional climate model RegCM3

The effect of the lateral boundary scheme in regional climate model (RCM) on the track simulation of tropical cyclone (TC) was investigated using RegCM3, for the case of Winnie (1997), which formed in the Western Pacific and landed on China in August 1997. The results show that there is an inevitable simulation error in the track of Winnie, and the narrower buffer zone size (BZS) will make a great error. However, it was demonstrated that a much broader BZS does not allow a better track simulation of Winnie, and the optimal BZS does not reduce the track error substantially. Moreover, the configuration scheme of nudging parameters plays an important role in the track simulation, and different nudging parameter configuration scheme could make the root mean square errors (RMSEs) of simulated track by more than two times. Nevertheless, the optimal configuration scheme can reduce the track error effectively by maintaining the equilibrium between the two additional nudging terms in the prognostic equations in the buffer zone, whereas both the strong nudging scheme and the weak nudging scheme distort the track simulation of the Winnie. It is also found that the simulated weaker west Pacific subtropical high (WPSH), which leads to the turning of the TC ahead of time, is the reason for the track simulation error. A possible approach for reducing track simulation error of TCs is also discussed.

How Can We Estimate Buffer Zones of Protected Areas? A Proposal Using Biological Data

A strategy to avoid the loss of habitats and preserve large areas is the establishment of protected areas. Brazil’s Conservation Units National System (SNUC) determines that protected areas should be surrounded by buffer zones where human activity is restrict, but the established size of the buffer seems arbitrary. The restrictions provided by SNUC could be based on limits that allow the persistence of species’ ecological function. Here we use the “landscape species” concept as a tool for buffer zone design, using the marsupial Micoureus paraguayanus as a model organism. We used its minimum area requirement for population viability (5,000 ha) to define the size of buffer zones around protected areas with smaller size that the minimum required area. The amount of habitat within protected areas was negatively correlated with the buffer size. Therefore, the largest the protected area, the smaller should be its buffer zone, provided that it does not have an impermeable barrier. Buffer zones are generally in private properties and, therefore, governmental incentives are essential to stimulate land uses compatible with biological flux through a permeable matrix. The method proposed here provides a simple analysis that can be used to establish the limits of buffer zones.

Further study on the effect of buffer zone size on regional climate modeling

In this study, the effect of buffer zone size on the performance of a regional climate model (RCM) was investigated. In contrast to carrying out simulations where the buffer zone expands inward, numerical experiments were performed with the buffer zone expanded outward, which ensured an objective comparison on the effect of buffer zone sizes. Case simulations on the abnormal 1998 East Asian summer monsoon demonstrated that an RCM’s performance depended on the outward expansion of the buffer zone. Moreover, a broader buffer zone is able to improve large-scale circulation simulation in the upper troposphere; however, a narrower buffer zone shows better performance in the middle and lower troposphere. Numerical experiments show that the performance of RCMs in simulating the seasonal evolution of rainbands over eastern China is not completely consistent with that of the western Pacific subtropical high (WPSH). A possible reason why the configuration with the buffer zone expanding inward can improve the extension/withdrawal of the summer monsoon and the associated precipitation evolution over eastern China is discussed.

Assessing the Capability of a Regional-Scale Weather Model to Simulate Extreme Precipitation Patterns and Flooding in Central Texas

Abstract A regional-scale weather model is used to determine the potential for flood forecasting based on model-predicted rainfall. Extreme precipitation and flooding events are a significant concern in central Texas, due to both the high occurrence and severity of flooding in the area. However, many current regional prediction models do not provide sufficient accuracy at the watershed scale necessary for flood mitigation efforts. The Weather Research and Forecasting (WRF) model, created with the purpose of improving upon the current fifth-generation Pennsylvania State University–National Center for Atmospheric Research (PSU–NCAR) Mesoscale Model (MM5), is specifically designed for regional grid spacings of 1–10 km. Previous research by the authors resulted in the development of a regional-scale prediction system over the San Antonio River basin, using a geographic information system (GIS) database, a hydrologic model, and a hydraulic model. Observed precipitation drives the prediction system; the authors hypothesize that the WRF model has the potential to predict flooding, at a lead time of several days, with a level of accuracy near that of observed precipitation. Causes of model error are also investigated, to determine the relative errors caused by model physics, initialization interval, buffer zone and domain size, and small-amplitude random errors. Results show that the Betts–Miller–Janjić cumulus and Lin et al. microphysics schemes, 48-h initialization interval, and two-domain configuration covering minimal ocean and having a parent-to-nest area ratio of greater than 10 best simulates a recent (July 2002) large storm event over the San Antonio River basin. This particular storm was selected because it produced extreme rainfall volumes and intensities, and also because its meteorological characteristics are typical of central Texas storm events. Location errors in rainfall are most significant because of their typically nonlinear patterns (increasing location error does not linearly modify streamflow output). Errors in intensity and timing show a more predictable (linear) watershed response that may be useful in the estimation of streamflow ranges for flood forecasting.

Demographic Consequences of Terrestrial Habitat Loss for Pool‐Breeding Amphibians: Predicting Extinction Risks Associated with Inadequate Size of Buffer Zones

Much of the biodiversity associated with isolated wetlands requires aquatic and terrestrial habitat to maintain viable populations. Current federal wetland regulations in the United States do not protect isolated wetlands or extend protection to surrounding terrestrial habitat. Consequently, some land managers, city planners, and policy makers at the state and local levels are making an effort to protect these wetland and neighboring upland habitats. Balancing human land-use and habitat conservation is challenging, and well-informed land-use policy is hindered by a lack of knowledge of the specific risks of varying amounts of habitat loss. Using projections of wood frog (Rana sylvatica) and spotted salamander (Ambystoma maculatum) populations, we related the amount of high-quality terrestrial habitat surrounding isolated wetlands to the decline and risk of extinction of local amphibian populations. These simulations showed that current state-level wetland regulations protecting 30 m or less of surrounding terrestrial habitat are inadequate to support viable populations of pool-breeding amphibians. We also found that species with different life-history strategies responded differently to the loss and degradation of terrestrial habitat. The wood frog, with a short life span and high fecundity, was most sensitive to habitat loss and isolation, whereas the longer-lived spotted salamander with lower fecundity was most sensitive to habitat degradation that lowered adult survival rates. Our model results demonstrate that a high probability of local amphibian population persistence requires sufficient terrestrial habitat, the maintenance of habitat quality, and connectivity among local populations. Our results emphasize the essential role of adequate terrestrial habitat to the maintenance of wetland biodiversity and ecosystem function and offer a means of quantifying the risks associated with terrestrial habitat loss and degradation.

Implications of processing spatial data from a forested catchment for a hillslope hydrological model

The objective of this study was to investigate with aid of a hillslope hydrological model (1) how landscape forms and land-use types control runoff generation and nitrogen leaching and (2) how the inevitable simplifications made when representing the entire catchment by a single hillslope (characteristic profile) affect modelled water and nitrogen fluxes. Analysis of the effect of hillslope shape parameters (e.g. length and slope) indicated that in forested hillslopes the modelled nitrogen export had a strong linear relationship with the share of subsurface runoff from the total runoff. The fraction of subsurface runoff, however, showed a non-linear relationship to changes in the profile length and slope. Decrease in length, and increase in slope, lead to a greater fraction of subsurface runoff. The non-linearity in the relationship implies that estimation of both the subsurface fraction and the nitrogen load is distorted when sub-areas producing large fractions of subsurface flow are aggregated with areas generating only little subsurface runoff into a single characteristic profile. In constructing the characteristic profile, aggregation of areas having different forest stand/soil properties causes the upslope drainage areas and the flow pathways to the stream to become distorted. The effects of such distortion were found to be particularly high for ammonium as its behaviour – due to efficient retention in soil – is highly non-linear with respect to the distance from the source area into the stream (i.e. size of buffer zone). In case of nitrate, which was considered not to be retained in soil, the role of groundwater table at the source area (clear-cut) was identified to be a more important control than the buffer zone size. As the upslope parts of a catchment have a significant role in determining the groundwater table at the treatment site, a question arises whether in addition to buffer zones one should also turn the attention upslope of the nitrogen source areas. Clearly patterns of landscape, such as distribution of nitrogen source areas in this study, pose challenges in selecting the spatial description for environmental simulation models. In nutrient leaching models, which easily become complex when based on process descriptions, compromises are needed to trade off between model complexity and the way how realistically landscape is described.

EFFECTS OF HUMAN DISTURBANCE ON USE OF SPACE AND FLIGHT DISTANCE OF MOUNTAIN GAZELLES

We studied the impact of proximity to human concentrations, hikers, and field vehicles on mountain gazelles (Gazella gazella gazella) space-use patterns, flight distance, and visibility in the southern coastal plain of Israel. We collected data on gazelle behavior and human disturbance from fixed observation sites, drive counts, and pellet counts. The density of pellets was positively correlated with the distance to human concentrations, and the flight distance was positively correlated with human disturbance level, suggesting mountain gazelle space use and flight distance were affected by human disturbance. Gazelles were less visible in the more disturbed areas. Our findings provide a framework for conservation measures such as determining the size of buffer zones and where and when enforcement efforts should take place to keep mountain gazelle populations viable in spite of the ecological impacts of human encroachment on mountain gazelle habitat.

EVALUATION OF BUFFER ZONE SIZE AND INSPECTION NUMBER REDUCTION ON PHYTOSANITARY RISK ASSOCIATED WITH FIRE BLIGHT AND EXPORT OF MATURE APPLE FRUIT

EVALUATION OF BUFFER ZONE SIZE AND INSPECTION NUMBER REDUCTION ON PHYTOSANITARY RISK ASSOCIATED WITH FIRE BLIGHT AND EXPORT OF MATURE APPLE FRUIT

Validation of SpraySafe Manager, an aerial herbicide application decision support system

Spray Safe Manager (SSM) is a computer-based aerial application model, which unlike previous models, has a simple user interface. SSM not only predicts spray deposition but also integrates this data with herbicide-plant dose-response curves. This latter facility allows the operator to predict the size of buffer zone required to avoid damage to sensitive plants outside the spray area and the degree of weed control within the spray block. Validation trials showed that, for a helicopter applied spray, the model tended to overpredict spray deposition on stainless steel plates close to the spray block and underpredict deposition in the region 32-80 m from the centre of the spray release line and on isolated plants. The accuracy of model prediction was greater when the spray was applied using D8-45 nozzles orientated at 90°, than for spray applied using D6 nozzles orientated at 0°. The reasons for this are discussed. The model can also be used to predict possible work rates, hectares sprayed per hour, and potentially as a training tool.

Regional modeling: A theoretical discussion

The goal of regional modeling is to make a detailed forecast for a given limited area of interst by focusing resolution over it and the immediate vicinity. As a consequence, the period of validity is necessarily more restricted than would otherwise be the case, and this is the price that must be paid for locally-enhanced resolution. The principal attributes of the non-interactive and interactive strategies for regional modeling are described. For the non0interactive strategy, particular emphasis is placed on the importance, difficulty, and impact, of well-posedness for open-domain problems. A methodology is given for estimating the size of numerical buffer zones required to obtain a forecast uncontaminated by the inward propagation of inaccurately-specified lateral boundary conditions. The interactive strategy addresses the well-posedness issue of (non-interactive) limited-area models. A computational overhead is incurred but this can be reduced through the use of variable resolution. It is argued that regardless of the preferred regional modeling strategy, experiments should be undertaken to today's regional models under carefully-controlled conditions, to reflect the significant reduction over the past two decades of other sources of error.

Determination of buffer zones to protect seedlings of non-target plants from the effects of glyphosate spray drift

There is an increasing need to protect semi-natural vegetation from the potential effects of herbicide drift. One way to protect sensitive sites is to surround them with a no-spray buffer zone. Earlier estimates of buffer zone size based on bioassay experiments with established perennials suggested zones needed to be 6–10 m wide. In this paper four bioassay experiments are reported, where seedlings grown in trays were exposed downwind of glyphosate applications and taken to a glasshouse for assessment. Three experiments were done with Lychnis flos-cuculi seedlings including one with different surrounding grass structures, and Experiment 4 tested the response of 15 species typical of semi-natural vegetation. The mortality of Lychnis flos-cuculi varied between experiments and appeared more or less unaffected by grassland structure except immediately downwind of the sprayer. The multi-species experiment indicated a wide sensitivity to spray drift, and one species was affected between 15 and 20 m downwind. Thus, seedlings of some species were affected at greater distances than established plants, indicating either greater capture of drift or a greater sensitivity. On sites where seedling establishment is an important mechanism for community regeneration, buffer zones may need to be 20 m wide.

Secondary contamination of 30-km zone of the Chernobyl atomic electric plant and adjacent territory due to radionuclides carried by ascending wind

The territory contaminated with radionuclides as a result of the accident at the Chernobyl atomic electric plant is a surface source of radioactive aerosols carried into the atmosphere by ascending winds. In this connection, a number of problems arise whose solution is important for assessment of the radiation conditions in the atmosphere near the Earth's surface, viz.: calculation of the volume concentration of radionuclides and their fallout on the contaminated and neighboring territory and on this basis determine the potentially dangerous contaminated regions; assessment of the secondary contamination of deactivated territories due to ascending winds and transfer of radionuclides; determination of the size of the protective (buffer) zones around or near populated areas to ensure low volume

Reproduction of Ferruginous Hawks Exposed to Controlled Disturbance

-The Ferruginous Hawk (Buteo regalis) is a conspicuous grassland bird that is sensitive to human disturbance. In 1978 and 1979, we studied 62 nesting pairs and recorded their behavior and nesting success. At 24 of these nests, we daily created disturbances designed to simulate those associated with land development on western rangelands. The other nests were not disturbed. Treated nests and control nests differed significantly (P < 0.05) in the number that successfully fledged young. Thirty-three percent of the disturbed nests were deserted by the adults, although our presence in the vicinity of the nest was brief. Those disturbed nests that were successful fledged significantly fewer young (P < 0.05) than undisturbed nests. Based on our cumulative data, adults did not flush 60% of the time if our activities were more than 120 m from the nest and 90% of the time if they were more than 250 m from it. Accordingly, for intermittent and brief human disturbance during years when prey are abundant and Ferruginous Hawks are in good physiological condition, we suggest that a minimum buffer zone of 0.25 km around the nest is sufficient to prevent nest desertion by at least 90% of the population. Buffer zone should be expanded in years when prey are scarce, i.e., when the hawks appear to be less tolerant of disturbance. The Ferruginous Hawk (Buteo regalis) is seriously affected in some areas by land development and, consequently some populations of the species are apparently small and may be declining. Reflecting this trend, the species has been on the Audubon Blue List since the list was established in 1971 (Tate and Tate 1982). A minimum number of breeding pairs was recently estimated at 2,810-3,590 over the entire range (M. Call, unpubl., U.S. Bureau of Land Management, Denver, CO, 1980). Ferruginous Hawks are particularly sensitive to human activity (Olendorff and Stoddard 1974, Fyfe and Olendorff 1976, Woffinden and Murphy 1977) and are prone to desert their nests if disturbed during incubation. Nonetheless, the species can respond well to management (White 1974, Porter and White 1976, Murphy 1978) so that it may be possible to adjust human activities to minimize ecological disturbance to it. Kennedy (1980) suggested such an approach in her assessment of conflicts concerning raptors and land use. It is becoming increasingly difficult to maintain critical wildlife habitat as the multiple-use demands on land intensify. The amount of disturbance that sensitive species will tolerate must be measured so that land management plans can be devised that are compatible with the species' needs. Our objectives were to determine how Ferruginous Hawks respond to disturbances, the levels of disturbances they will tolerate, and the size of buffer zones neede by disturbed pairs to maintain a level of nesti g success and productivity similar to those of undisturbed pairs. To accomplish this, we considered the natural tolerance thresholds of the species, the relationship of tolerance to prey availability, and the nesting history of the po ulation as related to disturbance. Most previous buffer zone recommendations from management agencies and the scientific community have been based primarily on best guess or anecdotal knowledge. Estimates of the sensitivity of Ferruginous Hawks, or raptors in general, to human disturbance were mainly obtained from observations made during studies of their breeding ecology. A significant exception is the Bald Eagle (Haliaeetus le cocephalus) for which considerable data were collected to aid development of sound management policies (cf. Grier 1969, Gerrard and Gerrard 1975, Mathison et al. 1977). Stalmaster and Newman (1978) examined the effects of some controlled disturbances on nonnesting Bald Eagles, but few other attempts hav been made to identify, quantify, and control variables that cause nest desertion. METHODS AND STUDY AREA We conducted our study throughout the Raft River Valley (42?N, 1130W), Cassia County, sou h-central Idaho (Fig. 1). The northern boundary of the valley opens onto the Snake

Ecological Boundaries for Coral-reef Reserves: Principles and Guidelines

As marine conservation activities intensify, planners and managers of protected areas are finding themselves with few guidelines or tools that are specific to the marine realm. Consequently the principles, criteria, and practices, of terrestrial protected areas tend to be transferred to the seas, where they are often inappropriate. In contrast to the situations with at all comparable sites on land, there is a sad shortage of published material on the application of ecological principles to the design and management of marine protected areas.Using the example of coral reefs, guidelines are presented here in the hope that they will elicit comment and stimulate the publication of similar guidelines for different marine environments.Coral-reef protected-area boundaries must fulfil two requirements: they must include appropriate coral-reef, confluent and neighbouring habitats, and a sufficient area of each. The first requirement defines the type, and the second the quantity, of habitats to be included in a protected area. Studies in the Chagos Archipelago, Indian Ocean, indicate that, there, the core zone of a protected coral-reef area should encompass 300 ha of diverse reef habitats if preservation of biotic diversity is the principal objective. The buffer-zone size needed will vary according to activities planned within the area, the extent of neighbouring coastal habitats, and the proximity of up-current or otherwise ‘linked’ sources of potential contamination.