Improving social acceptability of marine protected area networks: A method for estimating opportunity costs to multiple gear types in both fished and currently unfished areas

We present a novel method for calculating the opportunity costs to fishers from their displacement by the establishment of marine protected areas (MPAs). We used a fishing community in Kubulau District, Fiji to demonstrate this method. We modelled opportunity costs as a function of food fish abundance and probability of catch, based on gear type and market value of species. Count models (including Poisson, negative binomial and two zero-inflated models) were used to predict spatial abundance of preferred target fish species and were validated against field surveys. A profit model was used to investigate the effect of restricted access to transport on costs to fishers. Spatial distributions of fish within the three most frequently sighted food fish families (Acanthuridae, Lutjanidae, Scaridae) varied, with greatest densities of Lutjanidae and Acanthuridae on barrier forereefs and greatest densities of Scaridae on submerged reefs. Modelled opportunity cost indicated that highest costs to fishers arise from restricting access to the barrier forereefs. We included our opportunity cost model in Marxan, a decision support tool used for MPA design, to examine potential MPA configurations for Kubulau District, Fiji Islands. We identified optimum areas for protection in Kubulau with: (a) the current MPA network locked in place; and (b) a clean-slate approach. Our method of modelling opportunity cost gives an unbiased estimate for multiple gear types in a marine environment and can be applied to other regions using existing species data.     

Conservation importance of limestone karst outcrops for Palaeotropical bats in a fragmented landscape

Limestone karst landscapes are important for biodiversity yet are increasingly threatened by development activities such as mining. Furthermore, karsts are often scattered and isolated by agriculture, and are rarely considered in landscape planning because of a paucity of biodiversity data. We determined the conservation significance of an isolated limestone karst outcrop for insectivorous bats by quantifying the influence of this roosting resource on local assemblage structure across a fragmented landscape in peninsular Malaysia. Using a combination of rank abundance, gradient and randomisation analyses, we demonstrate that bat assemblages at nine forest sites are structured following a spatial gradient of increasing distance from a karst roosting resource. The assemblage at our karst site was dominated by a superabundance of three cave-roosting species, two of which were also found to dominate assemblages up to 11 km away. Cave-roosting bats exhibited a significant decay in abundance related to the distance from karst, with sites closest to karst also characterised by a rarity of tree cavity/foliage-roosting species that were otherwise common. Gradient analysis revealed that differences in assemblage composition were largely associated with the distance from the karst and, to a lesser extent, forest isolation and area. Our findings suggest that isolated karst outcrops can serve as important population reservoirs for cave-roosting bats, which subsidise diversity levels in forest fragments that might otherwise be expected to decline over time. While conservation efforts need to focus on maintaining large areas of connected forest, landscape management needs to ensure protection of karsts as point resources for cave-roosting bats.     

Designing a network of marine reserves in the Mediterranean Sea with limited socio-economic data

The present study is the first to determine priorities for the location of marine reserves using spatial prioritization software in the eastern Mediterranean Sea. We used biophysical data from visual census surveys on: fish species abundance, presence of various habitat types, and percent coverage of seagrasses and canopy algae. Efficient conservation planning requires spatially explicit information on how proposed management will affect stakeholders, which in this region was very limited. We created novel socio-economic cost indices to account for fisheries and tourists. Our fishing metrics were based on fisher behaviour including information on the location of ports and areas often inaccessible to fishers due to high wind exposure. We developed a cost index for tourism based on the availability of beds for tourists. We examined how the spatial priorities for marine reserves varied using different combinations of these socio-economic cost metrics. We found about 17% of sites were a high priority regardless of which cost metric was used. We also compared, for the first time in the Mediterranean, our results devised using systematic conservation planning approaches with priorities developed by two non-systematic methods, the Natura 2000 proposed marine reserves and sites that local fishers proposed for protection. Only a few sites identified by our approach were the same as those recommended as part of Natura 2000 or the fishers’ proposals. This suggests that much more work is needed to harmonise existing proposals with the principles of efficient systematic conservation planning.     

Socio-economic value and community benefits from shark-diving tourism in Palau: A sustainable use of reef shark populations

Arguments for conservation of sharks based on their role in the maintenance of healthy marine ecosystems have failed to halt the worldwide decline in populations. Instead, the value of sharks as a fishery commodity has severely reduced the abundance of these animals. Conservation may be assisted by the development of an alternative approach that emphasizes the economic value of sharks as a non-harvested resource. Our study quantifies the value of a tourism industry based on shark diving. Using data collected from surveys, as well as government statistics, we show that shark diving is a major contributor to the economy of Palau, generating US$18 million per year and accounting for approximately 8% of the gross domestic product of the country. Annually, shark diving was responsible for the disbursement of US$1.2 million in salaries to the local community, and generated US$1.5 million in taxes to the government. If the population of approximately 100 sharks that interact with tourists at popular dive sites was harvested by fishers, their economic value would be at most US$10 800, a fraction of the worth of these animals as a non-consumptive resource. Fishers earn more selling fish for consumption by shark divers than they would gain by catching sharks. Shark diving provides an attractive economic alternative to shark fishing, with distribution of revenues benefiting several sectors of the economy, stimulating the development and generating high revenues to the government, while ensuring the ecological sustainability of shark populations.     

Arable weed decline in Northern France: Crop edges as refugia for weed conservation?

The maintenance of biodiversity in agro-ecosystems is often viewed as an insurance against an uncertain future, yet, there is increasing evidence of biodiversity loss in agricultural landscapes. Here, we examined long term trends in the arable weed flora of North-East France by revisiting 158 arable fields initially surveyed in the 1970s. We assessed changes in species richness, density and frequency of occurrence in weed communities as well as for subgroups that are recognised for their conservation value. We also evaluated the importance of crop edges as potential refugia for the threatened arable weeds. Among the 121 species recorded in both surveys, 40% had significantly declined in frequency while 10% had significantly increased. At the field level, we recorded a 42% decline in species richness and a 67% decline in species density. Trends were comparable for weed species of particular conservation value. In the 2000s survey, crop edges harboured levels of weed diversity that were intermediate between those found in field cores in the 1970s and in the 2000s survey. Our results indicated that many species of conservation value had disappeared or seriously decreased in the field core but still persisted in the crop edge. The consequences of this general decline and possible conservation options are discussed in the light of the results.     

Climate change is linked to long-term decline in a stream salamander

Amphibian declines have been documented worldwide and several have been linked to climate change, but the long-term data needed to detect declines are largely restricted to pond-breeding species. This limits our knowledge of population trends in other major groups of amphibians, including stream salamanders, which have their greatest diversity in North America. I hypothesized that increasing air temperature and precipitation in northeastern North America caused abundance of the stream salamander Gyrinophilus porphyriticus in a New Hampshire population to decline between 1999 and 2010. I found a significant decline in abundance of G. porphyriticus adults over this 12-year period, and no trend in larval abundance. Adult abundance was negatively related to annual precipitation, which is predicted to increase further in the Northeast due to climate change. Analysis of a 6-year capture–mark–recapture data set for the same population showed no temporal variation in larval and adult detectability, validating the abundance data, and no variation in larval and adult survival. However, survival during metamorphosis from the larval to adult stage declined dramatically. These results suggest that increasing precipitation is causing a decline in adult recruitment, which, if it persists, will lead to local extinction. A likely mechanism for the decline in adult recruitment is mortality of metamorphosing individuals during spring and fall floods, which have increased in volume and frequency with the increase in precipitation. More broadly, this study presents strong evidence that the amphibian decline crisis extends to North America’s stream salamanders, and shows the critical need to collect population data on these species.     

Resource use and rarity among frugivorous birds in a tropical rain forest on Sulawesi

Relatively few studies have focussed on the relationship between resource use and rarity. Rare species could differ from common species in two ways: rare species may utilise resources that are themselves rarer or rare species may utilise a narrower range of resources than common species (i.e., they are more specialised). I investigated the relationship between local abundance and patterns of food resource use for an assemblage of 19 frugivorous birds in the tropical lowland rain forest of Sulawesi, Indonesia. Over a 10-month period I collected data on two measures of rarity, the local abundance and monthly variability in local abundance of each bird species, together with data on their feeding ecology including dietary specialisation, resource availability, resource overlap and habitat use. These measures produced 18 ecological variables, 17 of which I correlated with the two measures of rarity using univariate correlations and minimum adequate multiple regression models. These were carried out using the original data and independent contrasts that controlled for potential phylogenetic bias. Both measures of rarity were most strongly correlated with measures of resource availability. In both the original data and independent contrasts regression models of the temporal variability in bird abundance, only temporal fruit availability was included as a significant predictor. In the regression models of bird abundance, the strongest significant predictor was the amount of rare fruit in the diet (a negative relationship). Both models also included measures of resource specialisation, however, these were not significant in the absence of the measure of resource availability. On Sulawesi, rare frugivorous birds utilise rare resources. Specialisation, however, might be an important factor in species persistence once they become rare. The generality of the findings need to be tested.     

Shortcuts for marine conservation planning: The effectiveness of socioeconomic data surrogates

Marine protected area (MPA) networks designed without consideration of the interests of local communities are likely to fail. However, in many regions where conservation action is needed most urgently, socioeconomic data are not available at spatial scales relevant to conservation planning. In the Philippines, the primary stakeholders relevant to conservation efforts in coastal waters are small-scale fishers. Unlike commercial fisheries, no logbook data are kept to record fishers’ spatial effort and usage patterns. We investigated the effects of including different surrogates for small-scale fishing effort in the systematic design of an MPA network for Siquijor Province. We compared a reserve selection scenario in which socioeconomic data were not considered with four different surrogates for fishing effort and with empirical data on the spatial distribution of fishing effort collected through interviews. We assumed that minimising opportunity costs to fishers would increase the likelihood that they would support and comply with MPA implementation, resulting in more effective conservation. Surrogates modelled on the number of fishers or boats in each community consistently outperformed those based on population census data. However, none of the surrogates we tested were able to accurately predict fine-scale resource use patterns. Whilst socioeconomic surrogates may be able to assist conservation planners to identify regional-scale opportunities where conservation objectives may be met more easily, they cannot act as a shortcut for comprehensive consultation with communities, which will be required to identify actual sites for MPA implementation.     

Linking resource use with demography in a synanthropic population of common ravens

A thorough understanding of a population’s ecology requires knowledge of the relationship between habitat use, resource use and demographic parameters. We undertook an empirical investigation of habitat use, resource use and demography in a population of common ravens (Corvus corax), a species widely distributed throughout the Northern Hemisphere. The abundance of ravens is increasing in many parts of western North America, which represents a conservation concern since predation by ravens is thought to contribute to the decline of several sensitive species. We defined resources as the suite of physical and biological components in the environment that led to occupancy of a particular place by ravens. The home ranges of breeding and nonbreeding ravens contained similar proportions of resources, but breeding ravens used more edges, roads, forest, clearcuts, and towns than nonbreeders. We detected no differences in survival between the sexes, but breeding ravens survived at higher rates than nonbreeders, due to exclusion by breeding ravens from those resources positively associated with survival. Raven use of mature forests and anthropogenic land use types was positively associated with survival. Breeding raven use of clearcuts and patchy areas contributed to increased reproduction, but the use of clearcuts along with the use of roads was negatively associated with survival due to illegal shooting. Greater insight into the demography of synanthropic species such as the common raven will enable managers to make informed decisions for protecting biodiversity. This study is the first to consider the demographic consequences of habitat use and resource use for both nonbreeding and breeding common ravens.     

Large mammal population declines in Africa’s protected areas

Protected areas (PAs) are the cornerstone of global conservation efforts but their performance in maintaining populations of their key species remains poorly documented. Here, we address this gap using a new database of 583 population abundance time series for 69 species of large mammals in 78 African PAs. Population abundance time series were aggregated to form a multi-species index of overall change in population abundance. The index reveals on average a 59% decline in population abundance between 1970 and 2005. Indices for different parts of Africa demonstrate large regional differences, with southern African PAs typically maintaining their populations and western African PAs suffering the most severe declines. These results indicate that African PAs have generally failed to mitigate human-induced threats to African large mammal populations, but they also show some successes. Further development of our index could help to measure future progress towards post-2010 targets for reducing biodiversity loss.     

Habitat selection by the common wombat (Vombatus ursinus) in disturbed environments: Implications for the conservation of a ‘common’ species

The construction of habitat models is a repeatable technique for describing and mapping species distributions, the utility of which lies in enabling management to predict where a species is likely to occur within a landscape. Typically, habitat models have been used to establish habitat requirements for threatened species; however they have equal applicability for modelling local populations of common species. Often, few data exist on local populations of common species, and issues of abundance and habitat selection at varying scales are rarely addressed. We provide a habitat suitability model for the common wombat (Vombatus ursinus) in southern New South Wales. This species is currently perceived as abundant throughout its extensive range across temperate regions of eastern Australia, yet little factual survey data exist and populations appear under threat. We use wombat burrows to reflect habitat selection and as our basis for ecological modelling. We found that environmental variables representing proximity to cover, measures of vegetation and proximity to watercourses are important predictors of burrow presence. Extrapolation of habitat models identified an abundance of habitat suitable for burrows. However, burrows in many suitable areas were abandoned. Our estimate of the population size was similar to the total annual mortality associated with road-kill. Theoretically, given the availability of suitable habitat, common wombat populations in the region should be thriving. It seems likely that this area once supported a much higher number of wombats; however limiting factors such as road mortality and disease have reduced the populations. The persistence of wombats in the study region must be supported by migration from other populations. Our findings challenge the perception that wombats are currently common and not in need of monitoring, suggesting that perceptions of abundance are often clouded by socio-political motives rather than informed by biological and ecological factors.     

Do partial marine reserves protect reef fish assemblages?

Fish assemblages in the Mimiwhangata Marine Park, an area closed to commercial fishing but open to most forms of recreational fishing, were compared with adjacent fished areas. Two survey methodologies were used; baited underwater video and underwater visual census. Snapper (Pagrus auratus), the most heavily targeted fish species in the region, showed no difference in abundance or size between the Marine Park and adjacent control areas. When compared to the fully no-take Poor Knights Island Marine Reserve and two other reference areas open to all kinds of fishing (Cape Brett and the Mokohinau Islands), the abundance and size of snapper at the Marine Park were most similar to fished reference areas. In fact, the Marine Park had the lowest mean numbers and sizes of snapper of all areas, no-take or open to fishing. Baited underwater video found that pigfish (Bodianus unimaculatus), leatherjackets (Parika scaber) and trevally (Pseudocaranx dentex) were significantly more common in the Marine Park, than in the adjacent control areas. However, none of these species are heavily targeted by fishers. Underwater visual census found similar results with five species significantly more abundant in the Marine Park and five species more abundant outside the Marine Park. The lack of any recovery by snapper within the Marine Park, despite the exclusion of commercial fishers and restrictions on recreational fishing, indicates that partial closures are ineffective as conservation tools. The data suggest fishing pressure within the Marine Park is at least as high as at other ‘fished’ sites.     

Monitoring the recovery of smalltooth sawfish, Pristis pectinata, using standardized relative indices of abundance

The US population of smalltooth sawfish, Pristis pectinata, is currently listed as endangered under the Endangered Species Act. An important component of monitoring the recovery of this species is establishing long-term baseline trends in abundance. In the absence of scientific survey data, assessing and monitoring the status of some marine species has required the utilization of fishery-dependent data. Using voluntary dockside interviews of sport fishers collected in Everglades National Park, a standardized index of abundance was created for smalltooth sawfish using the delta method. The index was developed as the product of separate generalized linear models of the proportion of positive trips and the positive catch rates on successful trips. Development of the final model included testing factors that were expected to influence the catch of smalltooth sawfish. The final model assumed a binomial distribution for the proportion of positive trips and a lognormal distribution for positive catch rates. Year was significant as a main effect in the binomial model whereas year and skill level of the fishing party were significant in the lognormal model. The relative abundance index shows a small increase in abundance at an average rate of about 5% per year since 1989. These results indicate that the population of smalltooth sawfish in Everglades National Park has at least stabilized and may be increasing. However, additional data and analyses from multiple sources are required before definitive conclusions on the recovery of smalltooth sawfish can be established.     

Herded cattle and wild grazers partition water but share forage resources during dry years in East African savannas

Wild herbivore diversity and abundance have declined in African savannas for the past 20 years. Competition for forage resources between wild herbivore and livestock species might contribute to this decline, given habitat and diet overlap under conditions of resource limitation. Development of conservation and management strategies rely on understanding the spatial distribution of resources for livestock and wildlife, especially since the combination of transhumance pastoralism and wildlife conservation is common over Africa. We studied the distribution patterns of wild grazers in relation to cattle abundance, and distance to permanent and seasonal water bodies in semi-arid Kenya between 1983 and 2000. Cattle were abundant far from permanent water bodies during dry and wet years. Wild grazers less dependent on water also concentrated far from water during all years. Only wild grazer species more dependent on water remained concentrated close to water. Hence, wild grazers and cattle show spatial partitioning in the use of permanent and seasonal water bodies, but not in their forage resources. Our study provides no strong evidence of spatial displacement of wild grazers by cattle. We suggest that pastoralist decisions on cattle distribution do not need to negatively affect wildlife distribution and that coexistence can be possible through spatial partitioning. Our results show that pastoralist decisions play an important role in the interactions between livestock and wildlife in African savannas and that herd mobility is a key component in supporting sustainable use of resources for both wildlife and livestock.     

A sensitivity analysis to guide research and management for Hector's dolphin

Hector's dolphin (Cephalorhynchus hectori) is an uncommon endemic of New Zealand which is suspected to be in decline due to entanglement mortality. However, uncertainty in available data has led to a dispute between the New Zealand Ministry of Fisheries and the New Zealand Department of Conservation over the status of this species. We use a density-dependent deterministic model to predict the future abundance and geographic distribution of Hector's dolphin under different scenarios of fisheries management. We then examine the sensitivity of this model to a number of parameters for which few or no data are available. We find that two populations of Hector's dolphins are predicted to decline in the future even when the most optimistic parameter estimates are used. The status of the third population is dependent upon the estimate of maximum annual population growth rate. Because of the dependence of final abundance estimates on the estimates of entanglement mortality rates and maximum population growth rate, research efforts should be concentrated on estimating these parameters.     

Conservation cornerstones: Capitalising on the endeavours of long-term monitoring projects

Ecological monitoring is widely used to measure change through time in ecosystems. The current extinction crisis has resulted in a wealth of monitoring programs focussed on tracking the status of threatened species, and the perceived importance of monitoring has seen it become the cornerstone of many biodiversity conservation programs. However, many monitoring programs fail to produce useful outcomes due to inherent flaws. Here we use a monitoring program from south-eastern Australia as a case study to illustrate the potential of such endeavours. The threatened carnivorous marsupial, the brush-tailed phascogale (Phascogale tapoatafa), has been monitored at various locations between 2000 and 2010. We present strong evidence for a decline in relative abundance during this period, and also describe relationships with environmental variables. These results provide insights likely to be valuable in guiding future management of the species. In the absence of the monitoring program, informed management would not be possible. While early detection of population declines is important, knowledge of the processes driving such declines is required for effective intervention. We argue that monitoring programs will be most effective as a tool for enhanced conservation management if they test specific hypotheses relating to changes in population trajectories. Greater emphasis should be placed on rigorous statistical analysis of monitoring datasets in order to capitalise on the resources devoted to monitoring activities. Many datasets are likely to exist for which careful analysis of results would have benefits for determining management directions.     

Are urban parks refuges for bumble bees Bombus spp. (Hymenoptera: Apidae)?

Declines in bee populations have been documented in several parts of the world. Bees are dependent upon flowering plants for resources, and flowering plants often depend upon bees for pollination services. Bees can therefore serve as indicator species of habitat degradation due to these relationships with flowering plants. This study investigates how the bumble bee community in San Francisco has responded to urbanization and which urban park characteristics are important for the current community’s structure. To answer these questions we sampled bumble bees, in 18 urban parks and two nearby wild parks. We estimated park characteristics and used multiple regression analysis to determine which characteristics predicted bumble bee abundance and species richness. Bumble bee abundance was positively associated with resource availability or proxies of resource availability; “natural area” (areas that contain remnant fragments that have been largely unchanged by human activity) in 2003 and nest site abundance and openness of the surrounding matrix in both 2003 and 2004. Bumble bee species richness was negatively associated with abundance of a dominant species, Bombus vosnesenskii, in 2004. The importance of the surrounding matrix suggests that these parks do not act as islands. Accordingly, area of park did not explain species richness, while abundance of the dominant competitor did. The species that was most influenced by competition, Bombus sitkensis, uses rodent holes as nest sites and is possibly excluded from nest sites by the early emerging B. vosnesenskii, another subterranean nester. The species least influenced by competition, Bombus melanopygus, is able to use both rodent holes and abandoned bird nests as nest sites.     

The proportion of immature breeders as a reliable early warning signal of population decline: evidence from the Spanish imperial eagle in Doñana

Methods to evaluate population trends have recently received particular attention because of perceived declines in several species during the 20th century. We investigated whether age at first breeding could be used as an “early warning signal” to detect possible changes in population trends in long-lived species with deferred maturity using data from the Spanish imperial eagle (Aquila adalberti) population in Doñana National Park (Spain). This bird of prey is an endangered species that has suffered a rapid decline in this population during the last 10 years. As a result of our 27-year monitoring (1976-2002) study, we detected that an increase in immature breeding birds occurred before population decline became evident. The proportion of immature-plumaged breeders in the population was significantly higher during the period of decline than during the period of stability. In our case, more than 10% of immature breeders can be considered as an “early warning signal” that anticipates population decline. Owing to the ignorance of this warning signal, urgent actions for the recovery of this eagle population started 10 years later than necessary, and when population size had been reduced.     

A priori valuation of land use for the conservation of black rhinoceros (Diceros bicornis)

The appropriateness of using carrying capacity (CC) estimates to indicate habitat utilisation for a particular species, and thus as a tool for conservation population planning, has been questioned. We argue individual fitness is driven by resource availability, and we therefore assume individuals select habitats with a higher quality, abundance, and availability of key resources. In the past such selection has been related to the CC of a habitat. We tested whether we can use CC estimates to indicate habitat selection by individuals using a selective forager, black rhinoceros Diceros bicornis, for which CC approaches underpin species conservation plans. We tested for correlation of individuals’ habitat selection with predicted CC values at three spatial scales of selection. Individual selection was not related to the value of the habitat according to our CC estimates for any of the three scales we tested at. We discuss how density-dependence, environmental variables, scale of selection, individual variation and intra- and inter-specific dynamics may have influenced these results. Following this, we question the use of a priori calculations of potential resource quality and abundance of habitats (CC estimates), which do not take into account the various factors that influence an animal’s selection of a habitat, as an indicator of species habitat selection. We raise caution regarding the use of such CC models to determine optimal population numbers for an area.