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JRBM was supported in part by Panthera and National Science Foundation Coupled Human and Natural Systems Grant 115057.

Fencing is a nearly ubiquitous infrastructure that influences landscapes across space and time, and the impact of fences on wildlife and ecosystems is of global concern. Yet the prevalence and commonness of fences has contributed to their “invisibility” and a lack of attention in research and conservation, resulting in a scarcity of empirical data regarding their effects. Stakeholders, including scientists, conservationists, resource managers, and private landholders, have limited understanding of how fences affect individual animals, populations, or ecosystem processes. Because fences are largely unmapped and undocumented, we do not know their full spatial extent, nor do we fully comprehend the interactions of fences with wild species, whether positive or negative. To better understand and manage fence effects on wildlife and ecosystems, we advocate for an expanded effort to examine all aspects of fence ecology: the empirical investigation of the interactions between fences, wildlife, ecosystems, and societal needs. We first illustrate the global prevalence of fencing, and outline fence function and common designs. Second, we review the pros and cons of fencing relative to wildlife conservation. Lastly, we identify knowledge gaps and suggest research needs in fence ecology. We hope to inspire fellow scientists and conservationists to “see” and study fences as a broad-scale infrastructure that has widespread influence. Once we better understand the influences and cumulative effects of fences, we can develop and implement practical solutions for sustaining wildlife and ecosystems in balance with social needs.

Roads are one of the most prevalent threats to wildlife because they fragment landscapes and increase mortality. In response to the threat of roads to population persistence, road-effect mitigation strategies are increasingly common, typically as a combination of exclusion fencing to reduce mortality and crossing structures to enhance connectivity. To evaluate the success of mitigation structures at reducing road mortality of amphibians and reptiles, we conducted a six year paired Before-After-Control-Impact (BACI) experiment. We used road surveys to estimate the effectiveness of exclusion fencing, and a combination of hoop trapping, passive integrated transponder tag scanners and camera traps to evaluate connectivity structure effectiveness. Exclusion fencing reduced the number of turtles and amphibians on the road but had no effect for snakes. Cameras recorded 54 turtles, 72 snakes, 615 frogs, and 271 salamanders using tunnels. PIT tag scanners detected similar usage by turtles (55 uses; 24 unique individuals) and snakes (69 uses; 15 unique individuals). Tunnel usage was neither spatially nor demographically biased, indicating that the tunnels were likely to be broadly used by the local species assemblage. Crossing rates of tagged individuals suggest ~5–15% of turtles and 44% of snakes are using crossing structures. We contextualized crossing rates with population size estimates for painted and snapping turtles in the surrounding habitats. Our study is one of the first of its kind to incorporate both a robust BACI design and the context of population-level effects to demonstrate the efficacy of road-effect mitigation for protecting wildlife, especially for reptiles and amphibians.

© 2017 Elsevier Ltd Roads are widespread features of many landscapes that can negatively affect wildlife, most notably through animal-vehicle collisions. Roadside fencing has increasingly been installed to help eliminate this source of mortality. While fencing may reduce road mortality, other types of wildlife responses to this novel barrier are not well understood. Here, we examined the movement behavior, space use, and carapace temperatures of Mojave Desert Tortoises (Gopherus agassizii) as they interacted with a roadside fence and an unfenced road. Using GPS loggers, we tracked tortoise movements for two years at 15-min intervals. We found that carapace temperatures were greater near structures (fence or unfenced road) than away from structures; tortoises near the unfenced road had higher mean carapace temperatures, but tortoises along the fence experienced more extreme upper temperatures that approached the species' thermal limit. Movement speeds were also higher along the structures than away from them. Tortoise home range sizes decreased with proximity to the fence or road; fragmentation of home ranges and road-crossing avoidance may have contributed to smaller home ranges along the fenced and unfenced road, respectively. While tortoises crossed the road significantly less than expected by chance, they did so primarily in May and July and in areas with washes, indicating that placement of roadside fencing and animal underpasses could be optimized by targeting areas where roads intersect washes. Taken together, our results suggest that roadside fencing can affect behavior, space use, and thermal ecology of tortoises, which may require refinements to future conservation strategies involving roadside fencing.

Anthropogenic infrastructure routinely interferes with wildlife movement, habitat use, and survival. Grouse in the family Phasianidae may be particularly susceptible to collisions with fences due to their morphology and life history. Because many Phasianid species are of conservation concern, managers often deploy markers on fences to reduce collision-associated mortality. However, scarce information on the effectiveness of different marker styles or the effects of local and landscape features on collision risk exists. Our objectives were to (1) determine the effectiveness of different marker styles in reducing collisions, (2) estimate the effects of local and landscape features on collision risk, and (3) evaluate an existing greater sage-grouse (Centrocercus urophasianus) collision risk model. We conducted greater sage-grouse collision surveys within Sublette County, Wyoming, USA in March and April of 2014 and 2015. Data were analyzed in a multi-scale occupancy model accounting for incomplete detection of collisions. We found substantial evidence for the ability of all markers to reduce collisions (~ 57% reduction), with little difference between the tested marker types. We found strong evidence for lower collision probabilities at fences with wood posts and on fences farther from leks. Our results also indicated a negative relationship between collision probabilities and the difference between fence and vegetation heights. We observed little evidence for differences in collision risk between areas defined as “high” or “moderate” risk in a pre-existing collision risk map. We recommend integrating fence marking into conservation practices requiring fencing, and prioritizing fence marking near leks in areas with greater fence exposure.

Rocky outcrops are geological features that encompass a wide variety of physical environments, including escarpments, overhangs, cliffs, tors, boulder-heaps and insular domes (inselbergs). They support high levels of species diversity and endemism, and provide stable micro-climates for thousands of years. They provide critical breeding sites for many top order mammalian and avian predators; nesting sites for colonial species such as seabirds, bats and swifts and ecological refuges for ancient lineages. Rock overhangs and caves also provide important insights into our ecological past where they contain the remains of extinct species. Because rocky environments are generally less fertile, steep-sided and less accessible than the surrounding landscape, they are typically less prone to human disturbances. Nonetheless, many rocky outcrops, particularly in commodity production landscapes, face a variety of threats including soil compaction and erosion caused by livestock; nutrient enrichment and weed invasion; introduced predators; and physical damage caused by recreational and quarrying activities. Even rocky outcrops in seemingly pristine environments may be affected by altered fire regimes, air pollution (including acid rain) and potentially climate change. In agricultural landscapes, various approaches have been taken to conserve rocky outcrops, including land acquisition for conservation, fencing from livestock and private land conservation agreements with landholders. In more intact landscapes, targeted actions to conserve rock-dwelling fauna include limiting human access to critical breeding sites, baiting to reduce pressure from introduced predators, restoring rock microhabitat and translocation of endangered species. Future management actions will need to involve better inventory of the biophysical attributes and fine-scale mapping to improve the awareness of these small natural features.

Using surveys of experts associated with 186 sites across 24 countries, we assessed the effectiveness of African protected areas (PAs) at conserving lions and their prey, identified factors that influence conservation effectiveness, and identified patterns in the severity of various threats. Less than one third of sampled PAs conserve lions at ≥ 50% of their estimated carrying capacity (K), and less than half conserve lion prey species at ≥ 50% of K. Given adequate management, PAs could theoretically support up to 4 × the total extant population of wild African lions (~ 83,000), providing a measurable benchmark for future conservation efforts. The performance of PAs shows marked geographic variation, and in several countries there is a need for a significant elevation in conservation effort. Bushmeat poaching was identified as the most serious threat to both lions and to wildlife in general. The severity of threats to wildlife in PAs and the performance of prey populations were best predicted by geographic-socioeconomic variables related to the size of PAs, whether people were settled within PAs, human/livestock densities in neighbouring areas and national economic indicators. However, conservation outcomes for lions were best explained by management variables. PAs tended to be more effective for conserving lions and/or their prey where management budgets were higher, where photographic tourism was the primary land use, and, for prey, where fencing was present. Lions and prey fared less well relative to their estimated potential carrying capacities in poorer countries, where people were settled within PAs and where PAs were used for neither photographic tourism nor trophy hunting.

With a growing global population, human-wildlife conflicts (HWCs) are intensifying and cost-effective mitigation strategies to conserve biodiversity and support rural livelihoods become increasingly relevant. This article presents evidence on how low-cost electric fencing (EF) technology can contribute to a peaceful coexistence between farmers and wildlife. Applying an economic analysis, the effectiveness of smallholders' predominant HWC mitigation strategies in Bhutan are assessed. In Bhutan, HWCs are severe and investments in EF are expanding with about 10% of agricultural land already fenced. The analysis reveals high effectiveness and profitability of EF compared with labor-intensive crop guarding strategies despite smallholders' high time preference. EF profitability particularly depends on net labor savings from reduced time-use for crop guarding. Results emphasize the need for collective action at the community level, since due to small landholdings individually operated EF schemes are unprofitable in most cases. The findings are robust across ecological conditions and variations in key parameters, such as the discount rate (reflecting smallholders' time preference) and opportunity cost of labor. Particularly in contexts where hunting is banned, investments in EF technology could be a main ingredient of comprehensive policies for wildlife conservation and agricultural development. Further research is needed to investigate the biological implications of large-scale fencing policies, the relevance of spatial spillover effects and game-theoretic aspects of community-based EF schemes.

Wildlife fencing in combination with crossing structures is commonly regarded as the most effective and robust strategy to reduce large mammal–vehicle collisions while also maintaining wildlife connectivity across roads. However, fencing and associated measures may affect landscape esthetics and are sometimes considered costly and unpopular. Therefore fence length is often minimized. We investigated 1) whether short fenced road sections were similarly effective in reducing large mammal–vehicle collisions as long fenced road sections (literature review), and 2) whether fence length influenced large mammal use of underpasses (two field studies). We found that: 1) short fences (≤ 5 km road length) had lower (52.7%) and more variable (0–94%) effectiveness in reducing collisions than long fences (> 5 km) (typically > 80% reduction); 2) wildlife use of underpasses was highly variable, regardless of fence length (first field study); 3) most highway crossings occurred through isolated underpasses (82%) rather than at grade at fence ends (18%) (second field study); and 4) the proportional use of isolated underpasses (compared to crossings at fence ends) did not increase with longer fence lengths (up to 256 m from underpasses) (second field study). If the primary success parameter is to improve highway safety for humans by reducing collisions with large ungulates, the data suggest fence lengths of at least 5 km. While longer fence lengths do not necessarily guarantee higher wildlife use of underpasses as use varies greatly between locations, wildlife fencing can still improve wildlife use of an individual underpass.

Invasive species can have negative and positive impacts for local communities. Conflict between these different values can complicate and sometimes prevent broad-scale management and decision-making. Multi-functional landscapes and community-based conservation paradigms have emerged as constructive approaches to integrating competing interests and the development of sustainable and locally meaningful management planning. Here, we report on a five year feral ungulate exclusion fence project that was used to focus local people's attention on the eco-cultural and socio-economic impacts of feral ungulate invasion in a remote Aboriginal-owned region of northern Australia. Exclusion of feral buffalo, horses and pigs from three culturally significant freshwater billabongs from 2009 to 2013 resulted in variable increases in smooth ground (from 64–93%), ground cover vegetation (from 18–95%) and water lily cover (bush food) (from 20–60%), dependent on the site. The reduction in feral animal ground surface damage in the fenced areas was fastest at the floodplain billabong, Nalawan, which took only a year to become negligible. At the two channel billabongs, Costello and Namaliwiri, feral animal damage was negligible after 3 years. Senior Aboriginal Traditional Owners of these areas were pleased that these environmental assets were protected, but only agreed on the wholesale culling of pigs. Despite recognition of the negative eco-cultural impacts of feral ungulates as observed through the exclusion fence project, they wanted to maintain buffalo and horse on their Country to financially benefit from potential pet-meat and live export industries. Fencing was requested for culturally meaningful sites including those that were used for fishing and were sacred. Fenced areas were viewed by Traditional Owners as “protected” areas of ecological and cultural resources. These multiple management preferences can be combined to build socio-ecological resilience into regional strategic planning for feral ungulate management that will deliver multiple benefits for local communities.

Wildlife vehicle collisions (WVC) are a threat to wildlife and humans, killing millions of animals of numerous species, as well as causing significant damage to vehicles, drivers and passengers. Road fencing is a highly effective mitigation measure at reducing WVC, however its large-scale implementation requires a high investment. We questioned how long it would take for savings from avoided collisions to offset the investments in road fencing mitigation, focusing on vehicle damage costs. Using the information of a 3-year systematic roadkill monitoring of 1158 km in Mato Grosso do Sul, Brazil, we estimated the real number of casualties accounting for bias in roadkill counting. We obtained information on the material costs on cars and trucks due to WVC and, considering the road traffic volume characteristics, estimated the total material costs resulting from collisions with larger animals. Cost-benefit analyses allowed estimating the time required to amortize the investment in fencing, considering its application along the full surveyed roads or only in hotspots of mortality. We recorded over 10,000 WVC, 40% of which involved animals that can cause significant material damage to vehicles, namely the endangered lowland tapir (Tapirus terrestris, n = 267) and giant anteater (Myrmecophaga tridactyla, n = 608). The average material cost per accident was US$ 885 ± 1575 (mean ± SD). We show that investments are likely to pay off in 16–40 years for the mitigation of the full roads, and in 9–25 years for hotspots of mortality. Thus, road mitigation is a win-win solution for increasing traffic safety for humans and reduces road-related negative effects on biodiversity.

Conservation of biodiversity is one of the great challenges faced by present societies. Establishment and fencing of protected areas to isolate biodiversity from human activities is one of the most popular methods for achieving this protection. Here we analyze two long-term (∼50 years) datasets on a diverse mammal community of 38 regularly occurring species including many of international conservation importance such as the rare, endemic mountain bongo (Tragelaphus eurycerus isaaci), the black rhino (Diceros bicornis), the elephant (Loxodonta africana), and the lion (Panthera leo). These data were collected in two different locations within a flagship protected area in East Africa. Our primary objective was to investigate patterns of wildlife populations and diversity before and after the installation of a perimeter electric fence. We find strong evidence for long-term human-induced edge effects at the site that is closest to the border of the protected area (Treetops); this site registered the strongest losses in total wildlife population numbers, aggregate wildlife biomass, and species richness. In contrast, wildlife populations at the site farther away from the edge of the protected area (The Ark) have remained relatively stable over the duration of the dataset. Our data reveal clear differentiation in the temporal changes of wildlife populations between the two sites. Establishment of the fence in 1989 led to temporary increases in wildlife populations near the park margins, but since the late 1990s these gains have been reversed and wildlife populations have continued to decline near the edge of the reserve. Without the intention of undermining the potential value of fences as conservation tools, our data suggest that fences are only as effective as the management and enforcement efforts that accompany them.

Preventing and mitigating human–wildlife conflicts are a top conservation priority, particularly in India where wildlife and high densities of people co-occur. We surveyed 1972 households from 1371 villages in a 7449-km2 area surrounding five reserves in the Western Ghats. Our observational study modeled self-reported crop and livestock loss and compensation access by households. Crop loss was reported by 64% of households and associated with growing cotton, sugarcane, coffee and rice. Livestock loss was reported by 15% of households, and associated with grazing animals inside reserves. Losses incurred by households varied across reserves, averaging INR Rs 23,010 for crop loss and Rs 5423 for livestock loss. Compensation receipt was reported by 31% of households, and associated with reporting loss to authorities and elephant related incidents. Overall, landscape estimated probability of crop loss was 0.91, livestock loss was 0.19 and compensation was 0.29. Common mitigation measures for crop protection were night watching (46%), fencing (34%) and scare devices (34%); and for livestock protection were closer watch on animals (7%), guard animals (3%) and fencing (2%). Among 13 reported mitigation measures, no individual measure appeared to be associated with lowering crop or livestock loss. Unexpectedly, reported losses were similar across all reserves with higher losses incurred by households closer to the reserves. We identified conflict hot spots and influential factors across five reserves to improve current management efforts directed at conflict prevention and mitigation, and this approach is extendable to other human-dominated wildlife rich landscapes.

Exotic predators can have detrimental impacts on indigenous fauna. Lethal predator control is commonly used to reduce predator impacts, but is not always feasible, effective or ethical. A promising non-lethal alternative is refuge supplementation for prey. We conducted a Before–After Control–Impact (BACI) experiment over 3 years to determine the relative effects of predator removal (by exclosure fencing) and artificial refuge supplementation on survival of McCann’s skink (Oligosoma maccanni) in duneland on Kaitorete Spit (South Island, New Zealand). Skink populations on 0.0625 ha-grids were randomly assigned to four treatment groups, each replicated four times: (a) predator exclosure only; (b) artificial retreats only; (c) exclosure + artificial retreats, and (d) control (no exclosure or artificial retreats), and monitored annually by pitfall trapping. Capture–recapture analysis was used to estimate the difference in annual survival probability between pre- and post-treatment periods. On average, survival increased only at grids that received the exclosure-only treatment (effect size of 0.03 (0.017–0.043; unconditional 95% CI)). Reduction in predator abundance (by lethal predator control or predator exclusion), but not artificial refuge supplementation, is predicted to benefit McCann’s skink. Our findings add to other studies highlighting the detrimental impacts of exotic predators on indigenous prey and calls for improved means of reducing predator impacts.

Conservation practitioners often rely on experience rather than scientific evidence when making management decisions. These experience-based measures can waste limited time and funding if the given conservation practice is ineffective. Unanalyzed conservation strategies may negatively impact the species that is being protected. The use of predator exclosures to increase hatching success in ground-nesting shorebirds has been studied for almost two decades, yet their effectiveness is still debated. In ecosystems where predation pressure is particularly strong, electrified exclosures have been adopted; however, there are no studies on their efficacy or potential negative impacts. We conducted a nest survival analysis for 10 years (1998–2007) of piping plover monitoring data to determine: 1) the effectiveness of predator exclosures and electrified predator exclosures, and 2) conditions associated with nest abandonments at electrified exclosures. We found that predator exclosures significantly increase nest hatching success. Electrified exclosures can also be very effective at increasing hatching success under certain conditions, but at sites with high human disturbance and red fox densities, the proportion of exclosed nests that are abandoned by parental adults becomes sizeable. The direct cause of nest abandonments remains unclear since fox behavior on beaches and the dynamics of foxes and plovers at exclosures have not been studied. Our results suggest that such information is necessary if conservation practitioners can make more informed use of this direct management measure.

Carex bigelowii–Racomitrium lanuginosum moss heath has high conservation value in Britain, being one of the most extensive near-natural habitats and also the preferred habitat of dotterel (Eudromias morinellus). This rare and attractive bird has declined in Britain in the past century, and loss of Racomitrium heath due to heavy sheep grazing and/or nitrogen deposition is probably responsible. Erection of snow fencing for a ski corridor across Carex–Racomitrium heath on Glas Maol, a mountain rising to 1068 m in the eastern Highlands, affected sheep (Ovis aries) usage, and so gave an opportunity to compare trends in botanical composition under different grazing intensities. We began monitoring in 1990, four years after the fence’s erection, and report trends up to 2002/03. Adjacent to the fencing (0–10 m away) sheep usage was much increased due to improved shelter, and C. bigelowii and R. lanuginosum declined, the latter sharply. Racomitrium cover was already reduced by a third in 1990, and fell by a further third over the next 12 years. Grass cover increased to nearly equal Carex cover 16 years after the fence erection. Dicranum fuscescens also spread but lichens declined. There was longer snow-lie near the fence, this being correlated with sheep usage despite somewhat different incidence, and logistic regression showed that for the 1990–1996/97 period Racomitrium loss was rather more closely related to snow-lie than to sheep pellet-group density, whereas Agrostis increase was highly significantly related to pellet-group density. Distant to the fence the composition of the Carex–Racomitrium heath changed little over 12 years of monitoring. Agrostis increased and C. bigelowii declined, both changes being significant but much smaller than adjacent to the fence. Also Polytrichum alpinum increased significantly and some lichens declined. For Racomitrium there was a fall of only 2.5% from its initial cover of 40% in 1990. Since the dung counts showed only a negligible reduction in sheep usage between plots at 13–15 and 43–45 m from the fence, the trends in composition recorded at positions 19–20 and 39–40 m from the fence apply to the extensive moss heath used by the dotterel on Glas Maol. These birds still nest in the distant zone, and we judge that the condition of the Carex–Racomitrium heath will remain satisfactory for them unless sheep usage increases by 25% or more. However, the ongoing loss of lichens and the sparsity of Vaccinium myrtillus imply that the current level of sheep grazing has appreciably modified this community from its former pristine condition.

Translocation of European wild rabbit Oryctolagus cuniculus L. is one of the most frequent management tools to increase rabbit density in Spain, both as prey of several predators that are threatened with extinction and for sport hunting. Nevertheless the elevated short-term mortality by predation makes translocations unsuccessful and increases their biological cost. Information on the factors affecting the short-term survival and dispersal of translocated rabbits is required to improve release management and increase performance of translocated rabbits, and to avoid the use of non-selective lethal methods for predator control. In this study we tested electric fencing and night-shooting as alternative to traditional release protocols, and the effects of vegetation cover and warren fencing on short-term survival and dispersal of rabbits. Night shooting performed during the first nights after release increased significantly the survival of rabbits, by hindering the activity of carnivores in the release area. The use of an electric fence enclosure also increased the performance of rabbits, but was not efficient to constraint rabbit dispersal. Rabbits released in areas with low vegetation cover showed higher mortality and dispersal distances than rabbits released in high cover areas. Warren fencing decreased both the dispersal of rabbits and the adverse impact of predation in low cover areas, but had no effect in high cover areas. Selection of high cover areas or warren fencing in low cover areas seem to be the most advantageous release conditions to decrease the short-term predation impact, reducing the biological cost of rabbit translocations and the risks for endangered predators derived from the use of traditional predator control practices during translocations.

Roads, especially large highways, can have significant impacts on wildlife movement and survival. This is especially true for wide-ranging species, such as mammalian carnivores. Some of these impacts may be mitigated if wildlife can find and utilize passageways under highways. To determine if underpasses and drainage culverts beneath highways are used by wildlife as movement corridors, we monitored 15 such passages near Los Angeles, California using remotely triggered cameras and gypsum track stations. We found that passages were used by a variety of species, including carnivores, mule deer, small mammals, and reptiles. Many types of undercrossings were utilized, indicating that passages beneath highways, even when not originally designed for wildlife, can provide important safe avenues for animals to cross roads. For mammals of conservation concern, including native carnivores and deer, passage dimensions, surrounding habitat, and the extent of human activity were assessed to determine if these factors influenced passage use by these species. Our results show that while many native mammals used passages beneath highways, the presence of suitable habitat on either side of the passage was a particularly important factor predicting use. For deer and coyotes, passage dimensions were also important and should be considered with the presence of suitable habitat when wildlife passages are planned or evaluated. To increase the likelihood of utilization and to help prevent animals from crossing road surfaces, we suggest that simple improvements such as habitat restoration near crossing points and animal-proof fencing that serves to funnel wildlife to passages, can facilitate animal movement between fragmented habitats that are bisected by roads.

The economic impact of elephants, Loxodonta africana, and predators, particularly lions, Panthera leo, on rural agriculturists in the Kwando region of the East Caprivi, Namibia was assessed from the years 1991 to 1995. Elephants were responsible for the greatest number of wildlife conflicts in the region, while lions had the greatest financial impact on farmers. Attempts were made to reduce conflicts between elephants and farmers using deterrents such as electrical fencing, trip-alarm techniques and elephant warning calls. Success of deterrents depended on the frequency of exposure to elephants, maintenance and the ecology of both humans and elephants in the region. Of the deterrent strategies explored, only electrical fencing reduced elephant damage at the community level. The future efficacy of electric fencing is uncertain, however, if elephants do not associate it with fear and possible death. Deterrent efforts played a role in improving relations between communities and conservationists. Scenarios for how human agricultural communities might co-exist with free-ranging elephants are discussed.

There is concern in Britain about damage to nature conservation from expanding populations of the non-native muntjac deer Muntiacus reevesi. In Monks Wood National Nature Reserve, muntjac attained a suffciently high population by 1985 for significant damage to coppice regrowth to result. Electric fences have been used since 1988 to protect sensitive areas. Observations on regrowth of ash Fraxinus excelsior showed that while damage inside fences was significantly reduced when compared with areas outside, the fences sometimes failed to provide adequate protection. Observations on all coppice areas fenced since 1988 revealed that the extent of canopy formation was positively related to the density of surviving stools and to the area of adjacent rides. Improvements are suggested for fence design and the siting of coppiced areas. Techniques are outlined for monitoring contemporary damage, for evaluating damage retrospectively and for assessing abundance of muntijac in order to predict the amount of damage they may cause.

About 150 feral goat herds occupy about 16% of New Zealand. They are pests because of their effects on indigenous biota. Since 1936, government agencies have attempted to eradicate or control many herds. Common flaws in control campaigns include confusing ends (protection of resources) with means (killing goats), no measures of effectiveness, and lack of sustained action where eradication is impossible. One of four strategic options may be adopted: no action—giving a stable but undesirable outcome; eradication— giving a stable and desirable outcome; annual sustained control— giving a stable and desirable outcome but only if inherently fickle government effort is sustained; and occasional sustained control—giving unstable outcomes with or without the desired results depending on the goals and hunting frequency. Control tactics used are hunting on foot with or without dogs, hunting from helicopters, poisoning natural foliage, and fencing.

Using air photographs taken in 1950, 1962, 1967 and 1971 at Camber, Sussex, the progress of sand dune stabilisation was quickly and successfully assessed. Early stabilisation work included the construction of sand traps and the planting of marram ( Ammophila arenaria L.) which was subsequently destroyed by heavy pedestrian and vehicle use. The later application of hydraulically sown seeds, coupled with fencing to regulate pedestrians and trap wind blown sand, proved successful.

A study was made of paths on a dune system at Winterton, Norfolk, by ground and aerial surveys and a map produced of the 35 km of major paths in 104 ha of dune. Experiments were carried out on the resistance to trampling of a tall Festuca ovina-Carex arenaria sward. Estimates were made of the comparative vulnerability of other plant communities. The range extended from Ammophila arenaria, which was 10 x as vulnerable, to a short rabbit-grazed sward, only 1 3 − 1 4 x as vulnerable. The more vulnerable habitats unfortunately attract more people. 42% of the paths at Winterton occur on the steep slopes dominated by Ammophila. Comparisons are made with a similar site at Meijendel where greater recreational pressure necessitated laid-out paths and fencing to control visitors. It is suggested that if visitor pressure increases at Winterton, similar management may also be required there.

On the Sands of Forvie National Nature Reserve, Aberdeenshire, Scotland, a low electric fence was tested as a barrier to foxes preying on sandwich terns and eiders. The fence was an effective deterrent, reducing fox visits to the general area by over two-thirds and turning back about 60% of those which did visit. Fox activity beyond the fence was thus reduced to about 16% of that expected without the fence. Crossing of the fence was rare (6% of encounters) but foxes were able to pass round the ends of the fence on unprotected intertidal areas. Where this became common and predictable it enabled selective removal of an individual fox causing damage, since the fence steered the animal to a predictable place.

A scientifically based management plan was developed for a recreation and natural area to allow high visitation while preserving the environment. A private organization managing the R.T. Crane Jr Memorial Reservation, and members of a public university, cooperated to examine human impacts, and develop and implement management strategies. Basic scientific research methods, including vegetation surveying and vegetation mapping, were combined with proven management techniques, such as constructing elevated boardwalks, fencing sensitive areas, and educating visitors. A resurvey of study sites two years after implementation of the plan confirmed the success of this project and suggested that a similar approach could be used in other contexts.