The decline of the sand lizard, Lacerta agilis L. Population on the sand dunes of the Merseyside coast,England

The population of the sand lizard Lacerta agilis in northwest England has declined sharply since 1930. The reasons for this decline are considered.Between Southport and the River Alt, approximately 50% of the sand dune habitat has been destroyed and a further 12% modified since 1801. Habitat losses resulting from building developments help to explain the sand lizard decline. The species has also disappeared from areas still supporting dune habitat. Here a combination of factors appear responsible, the effects of which are not uniform throughout the dune system.It is concluded that, in conjunction with a trend of less favourable climate over the last 15 years, habitat destruction, fragmentation and change of quality have brought about a catastrophic decline in the sand lizard population within the last 20 years. It is predicted that this population will become extinct before 2000 unless present trends are halted and adequate conservation measures taken.     

Rockfish (Sebastes) that are evolutionarily isolated are also large, morphologically distinctive and vulnerable to overfishing

In an age of triage, we must prioritize species for conservation effort. Species more isolated on the tree of life are candidates for increased attention. The rockfish genus Sebastes is speciose (>100 spp.), morphologically and ecologically diverse and many species are heavily fished. We used a complete Sebastes phylogeny to calculate a measure of evolutionary isolation for each species and compared this to their morphology and imperilment. We found that evolutionarily isolated species in the northeast Pacific are both larger-bodied and, independent of body size, morphologically more distinctive. We examined extinction risk within rockfish using a compound measure of each species’ intrinsic vulnerability to overfishing and categorizing species as commercially fished or not. Evolutionarily isolated species in the northeast Pacific are more likely to be fished, and, due to their larger sizes and to life history traits such as long lifespan and slow maturation rate, they are also intrinsically more vulnerable to overfishing. Finally, the set of northeast Pacific species that are both fished and most intrinsically vulnerable to fishing are among the most evolutionarily distinctive. These findings suggest that, at least for this clade, extra attention should be paid to evolutionary distinctiveness when prioritizing species for conservation.     

Management of the Northern Chesapeake Bay American shad fishery

The Shad fisheries of the Chesapeake Bay in Maryland have been declining since an 1897 peak of 7860 × 10³kg. No periods of stability have been recorded. Data are presented to trace the decline not only as a function of specific areas within the Northern Chesapeake Bay but also in terms of environmental problems and recruitment overfishing.The problem is related to improving the commercial fishing yield. An estimation of a maximum effort of 200,000 man-hours is suggested if a stable yield is to be approached. Methods for obtaining this goal include alternating of closed fishing areas, adoption of rest days, enforcement of fisheries regulations and reduction of the number of metres of gill net used per fisherman.     

Changes in commercially fished shellfish stocks and shorebird populations in the Wash, England

The Wash, in eastern England, supports internationally important populations of 11 species of shorebird. A major commercial shellfishery provides potential conflict between fishermen and nature conservation interests. During the 1990s, high fishing mortality and low recruitment substantially reduced the stocks of cockle (Cerastoderma edule) and mussel (Mytilus edulis). Population models, constructed from estimates of survival and recruitment, indicated that declines in the availability of cockles and mussels were associated with changes in oystercatcher (Haemotopus ostralegus) survival between 1970 and 1998, including three periods of mass mortality, and also the recruitment of juvenile birds to both oystercatcher and knot (Calidris canutus) populations. Emigration of knot may also have taken place. Cockle recruitment was dependent on climatic conditions, whereas mussel populations tended to be stable. The decline in mussel stocks, due to over-fishing, increased the vulnerability of the oystercatcher population to mass-mortality episodes in poor cockle years. The key to preventing major oystercatcher kills in future is to ensure sufficient mussels are available in poor cockle years. Recent cultivation of mussels in inter-tidal areas has been beneficial and is an important management tool for maintaining bird populations.     

Environmental uncertainty and commercial fishing: Effects on Peruvian guano birds

The roles of the El Niño phenomenon, a cessation of upwelling, and of human fishing in limiting populations of Peruvian guano birds (Guanay cormorant Phalacrocorax bougainvillii, Peruvian booby Sula variegata, and Peruvian brown pelican Pelecanus occidentalis thagus) were investigated using historical records and the scientific literature. In normal years, the combined populations of the three species showed an 18% increase per year. El Niños occurred at approximately five-year intervals and caused a population decrease of 17% and 35% desertion of nesting areas. In severe El Niños at approximately 12-year intervals, there was a mean decrease of 47% and complete nesting failure. El Niños varied in severity and a possible explanation is presented.In non-El Niño years, commercial fishing did not directly control bird populations through starvation of adults or drowning in nets. Increased commercial fishing apparently led to decreased nesting success: the greater the quantity of fish landed, the lower the percentage increase of the bird population that year.Short-lived, heavily-fished species such as anchoveta are in constant danger of population collapse during years of occasional, unpredictable reproductive failure. Bird populations could be maintained as buffers to prevent terminally-destructive overfishing by humans.     

Seasonal space-use estimates of basking sharks in relation to protection and political-economic zones in the North-east Atlantic

The basking shark Cetorhinus maximus is listed as Vulnerable (A1a,d, + 2d) worldwide, and Endangered (EN A1a,d) in the north-east Atlantic in the IUCN Red List. However, protection for this species is limited in European waters and varies spatially. Without information on the amount of time individuals spend in different areas, any potential risks to population levels from incidental capture, possible future exploitation and climate change will be difficult to assess. To quantify the annual space-use patterns within political-economic zones in the north-east Atlantic we used geolocation data from seven transmitter-tagged basking sharks tracked for 964 days (16,754 km). Basking sharks tagged within the UK protection zone off south-west England and north-west Scotland spent subsequently only about 22% (range, 2.4-47.7%) of time at liberty within this zone, and a further 30% in the UK fishing zone. Although only about 6% of time was spent in the territorial waters of Ireland and France, basking sharks remained in UK, Irish and French fishing and EEZ zones for over 71% of track time (range, 51.4-89.2%). Sharks did not occupy International waters away from the European shelf at any time. These results indicate basking sharks move between different economic zones and were not afforded statutory protection for the major part of the time (78%) they spent within preferred habitat on the European shelf. This demonstrates the limited capacity of the British protection zone for encompassing the greater part of shark space utilisation. Tracked basking sharks regularly crossed national zone boundaries suggesting that conservation measures for this species need to be framed on a European, rather than national, basis. This study highlights the need for better information about the movements and habitat use by marine animals if conservation strategies are to be truly effective.     

The changing extent and conservation interest of lowland grasslands in England and Wales: A review of grassland surveys 1930–1984

This study has examined the changing extent of lowland grassland, in England and Wales, over the last half century. The proportions of semi-natural, and agriculturally improved grasslands were also assessed.

Total grassland area has declined from 7·8 M ha, 50 years ago, to just 4·8 M ha now. The decline in extent of unimproved grasslands also started in the 1930s, accelerated through the war years, and has continued steadily ever since. The main agents, at first, were drainage and the plough. However, inorganic fertiliser use has increased simultaneously, improving even old unploughed grasslands.

Only 0·6 M ha of semi-natural and rough grasslands remain in lowland England and Wales, making up only 11% of the total grassland area. Semi-natural pastures excluding rough grasslands now cover only 0·2 M ha, 4% of the present-day grassland area and 3% of its area 50 years ago. Semi-natural pastures which survive have often seen some agricultural improvements, so that relatively few retain their conservation interest.     

Are edge bird populations doomed to extinction? A retrospective analysis of the common guillemot collapse in Iberia

In the first half of the XXth century, the common guillemot (Uria aalge) was the seabird with the largest breeding population in Atlantic Iberia (ca. 20,000 individuals), the low-latitude limit of the species breeding range. However, this population suffered a dramatic decline and is quasi-extinct at present. The decline was believed to be associated with reduced availability of pelagic prey fish due to climate change. In this study, we analyzed the population change of Iberian guillemots in the second half of the XXth century by means of a retrospective analysis. Our study showed that between 1960 and 1974 the guillemots in Iberia suffered a dramatic population crash (33.3% annual decline) and that subsequently, the population continued to decline at a slower annual rate (13.4%). Simulation models indicated that the factors driving the population crash should be related to adult survival, rather than reproduction. The analysis of environmental and fishery data suggested good climate conditions and higher or sustained availability of pelagic prey fish when the Iberian guillemots crashed. In contrast, relevant human-related factors were affecting adult mortality in that period, specially a rapid and large increase in the number of synthetic fishing nets. During the collapse, no conservation measures were undertaken to mitigate anthropogenic threats and it was assumed, in some extent, that this low-latitude edge population was somehow prone to extinction as a consequence of climate change. This study highlights that to carelessly attribute the decline of rear edge populations to climate change could be highly misleading if the population is suffering from other, particularly human, threats.     

Using a novel survey technique to predict fisheries stakeholders’ support for European eel (Anguilla anguilla L.) conservation programs

A novel variation of a multivariate stated preference method (the maximum difference conjoint approach) is presented in a survey designed to elicit the preferences of a fisheries stakeholder group (recreational anglers fishing in northern Germany) for a portfolio of measures to conserve European eel (Anguilla anguilla L.). Unlike other survey methods, our approach allows the separation of weight (i.e., relative importance of different conservation actions) and scale (i.e., perceived utility associated with different levels within one action) ascribed by stakeholders to conservation measures. The method also allows for trade-off decision-making and joint preference articulation for various conservation actions, and thus provides more realistic decision situations than other survey methods can achieve. We found that anglers prefer tighter than current eel fishing regulations but object to highly restrictive temporal closures. Confronted with an integrated eel conservation program, anglers were overwhelmingly willing to compromise, accepting tighter angling regulations provided that other sources of eel mortality are regulated concomitantly and eel stocking increased. Willingness to accept stricter regulation increased further when the suite of regulations delivered success in terms of increased eel escapement. We encourage the replication of the presented survey technique with other eel stakeholders groups, but also in other conservation contexts, to see if similar patterns of response behaviour emerge that would not have been visible in traditional opinion-type preference assessments. Our results suggest that implementation of eel conservation policies should consider joint regulation of sectors that potentially affect eel stock negatively. Otherwise, management failure and conflict is likely.     

Why are there fewer signs of mink in England? Considering multiple hypotheses

Understanding the causes that determine the spread and subsequent population trends of invasive species is important as it can help predict and manage their impact, as well as advance the theory of invasion. The American mink Mustela vison is a riparian mustelid and an invasive species in several countries. Mink have been introduced to England in the early decades of the last century and have been expanding their range until the mid-eighties. Since then, however, the number of sites occupied by mink has been declining. We investigated three possible causes of such a decline: (1) A downtrend of the fur farming industry; (2) An increase of European polecats Mustela putorius; (3) An increase of Eurasian otters Lutra lutra. Mink trends were derived from data collected by the National Otter Survey, a large-scale long-term survey of the whole of England from 1977 to 2002. We discuss how the observed decline in the number of sites occupied by mink may be due to a combination of an actual decrease in the distribution and density of mink and to a change in the focus of mink activities away from water, rather than to a change in their marking behaviour. Taken together, our results suggest that the decline of mink is related to an increase in the native otter population through interspecific competition, although at a local level also other factors may be important. As the otter population is still increasing, it is likely that the number of sites occupied by mink will continue to decline, a process that may be beneficial to aquatic and semi-aquatic species suffering from mink predation.     

From common to rare: The case of the Mediterranean common dolphin

Although overfishing has been recognized as responsible for the decline of major fish stocks, it has been less easy to demonstrate its indirect and detrimental effects on marine mammals, particularly dolphins. Competition with fisheries for the same food resources has been hypothesized to have led to the decline of several species of dolphins, including the endangered Mediterranean short-beaked common dolphin. Based on an ecosystem model for the Inner Ionian Sea Archipelago, a former hotspot for common dolphins in the Mediterranean Sea, we investigated the effect of increasing fishing effort on common dolphins, its prey and on marine biodiversity and we evaluated the outcomes of different fisheries closures (1 – closure of the purse seine fishery, 2 – closure of purse seine, trawl and beach seine fisheries, 3 – entire area closed to fisheries) ran between the years 2011 and 2030. Our results showed that local fisheries have negatively impacted the marine biodiversity of the ecosystem causing sharp declines of common dolphins and major fish stocks and weakening the robustness of the marine food web. The implementation of fisheries closures would gradually recover fish stocks, while common dolphins would increase more pronouncedly only if the study area was to be closed to all fisheries. As shown in this study, common dolphins have reflected ecosystem changes and degradation over time. Ensuring the survival of dolphin populations is thereby essential to enhance marine ecosystems and ensure sustainable fishing.     

National parks in Great Britain and the achievement of nature conservation purposes

The ten National Park Authorities of England and Wales are concerned mainly with landscape conservation and provision for outdoor recreation. Nature conservation is not primary park purpose and only authority has its own nature reserves. Nature conservation purposes are pursued in the parks as elsewhere by the Nature Conservancy Council and by the appropriate County Conservation Trust. The achievements of these two organisations—the former national and governmental, the latter local and voluntary—are compared and contrasted.The number of national Nature Reserves established by the Nature Conservancy nationally assessed. The Conservacy appears to have treated the parks much as it has treated the rest of the country. Local Conservation Trusts have also accorded the parks no more—but also no less—attention than elsewhere. Trust reserves tend to be more or less uniformally distributed throughout the counties of England and Wales. This pattern corresponds with the distribution of Trust members and arises because membership rates tend to be highest in the more rural areas (including the National Parks) where absolute population levels are low. Finally, the National Park Authorities themselves have all but neglected nature conservation purposes in the parks. This lack of interest is consistent with the low priority afforded to nature conservation by local authorities in general and by rural authorities in particular. But whilst past achievements have been slight, future prospects are, by comparison, quite bright.     

Palaeoecology of degraded blanket mire in South Wales: Data to inform conservation management

Many European blanket mires are degraded and contain few Sphagna. In Wales, more than half exhibit symptoms of degradation. We used palaeoecological techniques to chronicle recent vegetation history at two upland localities in South Wales to provide an understanding of the contribution of various factors in mire degradation and to aid wider conservation management strategies. The data suggest a major vegetation change post-dated the start of the industrial revolution. There was evidence for increased burning activity, but as this phenomenon was not present in all profiles it seems unlikely that fire was the principal or sole agent in vegetation change. Rather, increased atmospheric input, plus a change in grazing pressure, may have been responsible. The implications for conservation management are far-reaching. The present overwhelming dominance of Molinia at Hirwaun Common is unprecedented. So also is a local dominance of Calluna, shown in one area at Mynydd Llangatwg. Hence, the approbation often accorded to Callunetum needs to be tempered with the knowledge that its presence in the Mynydd Llangatwg landscape is not long-standing. Indeed, millennial-scale dominance of Sphagnum imbricatum characterizes the earlier record. Its demise and that of Drosera intermedia took place in historical times. Both localities show floristic impoverishment within the 20th Century, with relatively recent single-taxon supremacy. So, conservation management to reduce the current pre-eminence of Molinia would not run counter to long-established dominance; ways to achieve this are suggested. The methods used in this study have wide applicability in mire conservation.     

Indexing and display of soil survey data by means of feature-cards and boolean maps

A system is described for indexing information from soil survey by punched feature-cards. Soil and more general site information is recorded in the field, and other information is added to the records from published sources, air photographs and laboratory determinations. The records are numbered systematically by geographic location and stored in numerical sequence. The information on each record is analysed into a number of simple attributes or “features”, which are then used for indexing. For each feature there is a feature-card bearing a matrix of numbered positions corresponding to record numbers in the store. Each card is punched in the positions of all records that possess the feature. To identify and retrieve records, feature-cards are used either singly or superimposed in combination.The system has been applied to grid surveys in which sites at intersections of the National Grid are examined. The feature-card grid is oriented so that it represents to scale the National Grid. Each feature-card thus constitutes a map. By carrying out logical operations using the cards in combination, “Boolean” maps are swiftly derived.The system has been used satisfactorily in the Aberystwyth office of the Soil Survey of England and Wales for 7 years. Ultimately full automation is likely to bring advantages, but a punched feature-card system will be a useful aid for indexing soil survey information in any local soil survey office for some time to come.     

Isolation and the decline of the large blue butterfly (Maculinea arion) in Great Britain

In England Maculinea arion is on the verge of extinction and there have been many explanations for its decline. Evidence is put forward to show that at one time it was more widespread in England than is generally realised. It is argued that the fragmentation of this widespread distribution is, in itself, a prime cause of the butterfly's disappearance.     

Recent, substantial, and unexplained declines of the common toad Bufo bufo in lowland England

A decline in numbers of a large common toad (Bufo bufo) population in south-east England during the 1990s, together with anecdotal reports of similar trends in other toad populations, prompted a nation-wide survey of this species. The survey also included the common frog (Rana temporaria) as a control for which there was no comparable evidence of recent decline. A questionnaire requesting information on the fate of toad and frog populations in the last 15 years of the 20th century was distributed to professional and amateur herpetologists during autumn 2001. Ninety-five respondents provided data on a total of 277 sites, including 232 frog and 202 toad populations in England, Scotland and Wales. More than 80% of the reported sites were rural for both species. Rural frog populations were generally doing well in most parts of Britain, with almost as many increasing as decreasing populations and a high proportion of stable populations. Rural toads also showed no overall trend across the country as a whole. However, regional analysis indicated that although toads were faring at least as well as frogs in the north and west of Britain, they were declining seriously in central and eastern/south-eastern areas. In these regions 50% or more of toad populations have experienced recent declines, whereas frogs have fared as well as they have elsewhere. Toads breeding alone have fared significantly worse than toads breeding at sites where frogs were also present. Reasons for apparently toad-specific declines in lowland England remain unknown.     

Reedbeds as refuges for water voles (Arvicola terrestris) from predation by introduced mink (Mustela vison)

The water vole has recently undergone a catastrophic decline in the UK. This has resulted from loss and fragmentation of suitable habitat leaving water vole populations highly vulnerable to the impact of predation by introduced American mink. However, at some reedbed sites water voles and mink have apparently coexisted for many years. To determine if reedbeds offer a refuge from predation, 70 voles were radio-tagged at three sites in England and overwinter mortality monitored. Water vole perception of predation risk was also assessed. Mortality was high (64%), predation by mustelids, including mink, being the chief cause. Experiments suggested that voles failed to perceive areas of highest predation risk. However, predation rate declined strongly with the distance water voles lived from a main water channel. Thus, reedbeds provide a refuge from predation, even by mink, and calculations suggest that they may support source populations enhancing the viability of water vole metapopulations. Consequently reedbeds are now being used as one focus for the conservation of water voles in England and Wales.     

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.