Patterns of allozyme diversity in several selected rare species in Korea and implications for conservation

Because some endemic plants appear to be adapted to a narrow setof environmental conditions with limited genetic diversity, an analysis ofpopulation genetic structure is necessary to fully evaluate the impact of rarityon genetic variation. Listed as endangered species in Korea, only fewpopulations of Abeliophyllum distichum, Leonticemicrorhyncha, Bupleurum euphorbioides, andBerchemia berchmiaefolia were found. A reduced level ofgenetic variation in B. berchemiaefolia is consistent withthe occurrence of a genetic bottleneck and inbreeding. Leonticemicrorhyncha differed dramatically from other taxa in its observed level of geneticvariation, probably due to its predominant selfing. The level ofallozyme variation maintained by A. distichum was high forendemic species. Compared to species with similar traits, A.distichum maintained a relatively higher genetic diversity, probably dueto floral heteromorphism and preferred outcrossing. Bupleurumeuphorbioides maintained a higher genetic diversity due to outcrossing,but at the individual locus, deficiency of heterozygosity prevailed. Probablyinbreeding between local neighborhoods was frequent because A.distichum and B. euphorbioides were pollinatedby small fly species which might be less effective as a pollen dispersal, andtheir visits were extremely scarce and controlled by the weather conditions.Since much of the species-to-species variation in genetic diversity is due tothe specific ecological and evolutionary history of a species, any managementplan developed should be based on historical changes in the population size anddistribution to better predict the amounts and patterns of genetic diversity.     

Chains of opportunity: A Markov model for acquisition of reusable resources

Summary A vacancy chain is a unique type of resource acquisition process composed of an interconnected series of events in which the gaining of a particular resource unit by one individual depends directly on prior acquisition events by other individuals. Taken from the sociological literature, vacancy chains may also describe the distribution of many types of animal resources such as burrows, dwellings and shelters. Using data on hermit crabs, we present a Markov model simulating a vacancy chain process, and test the model against field data. Our results show that a simple Markov model adequately describes shell acquisition in hermit crabs, and that models combining shell size and crude estimates of quality fit the data extremely well. We illustrate in detail how to generate vacancy chain models from ecological data, how to determine the number and size of organisms gaining new resource units from resource introductions of specific sizes, and how to statistically evaluate the accuracy of Markov models. Not recognizing the presence of a vacancy chain system may lead to serious errors in estimating resource dynamics and therefore in demographic and competition models based on these dynamics. Finally, we suggest some ways in which vacancy chain models can aid studies of competition, population dynamics, life histories, and conservation in species using this type of resource acquisition process.     

Lead poisoning and heavy metal exposure of golden eagles ( Aquila chrysaetos ) from the European Alps

Lead poisoning and organ levels of the non-essential heavy metals lead, cadmium and mercury of seven free-ranging golden eagles (Aquila chrysaetos) from the European Alps, and of one 23-year-old captive golden eagle are reported. All birds were found dead or moribund during the years 2000 and 2001 in Austria, Germany and Switzerland. One golden eagle from Switzerland with extraordinarily high lead residues in its liver and kidney was clearly identified as lethally lead poisoned. Another bird from the same region was found still alive and died in a wildlife rehabilitation center, showing lead residues in its organs known for acute lead poisoning with detrimental physiological effects, such as nervous disorders and the inhibition of the hemoglobine synthesis. Concentrations of cadmium, mercury and lead residues in the organs of the other five free-ranging birds, and in the long-lived captive golden eagle, were low and represent the natural background levels in birds of prey of the terrestrial food web. This is the first published report of lead poisoning in golden eagles from Switzerland. Sources for lead poisoning in golden eagles in the Alpine region are discussed.     

Linking fisheries management and conservation in bioengineering species: the case of South American mussels (Mytilidae)

We examined a complete list of South American mussels (Mytilidae) to identify species with current or potential needs for management and conservation actions. Based on ecological/ecosystem (aggregations, beds or banks affecting ecosystem functioning) and socio-economic (artisanal fisheries or aquaculture systems) attributes species with high relevance were identified. At least 14 species exhibited large ecosystem level effects at local scales. Further, most of them also sustain important fisheries: nearly one/third of these fisheries showed characteristics that may contribute to their lack of sustainability and overexploitation, while half are either in the initial exploitation phase or in the stabilization of extraction and institutionalization phase. Invading species are modifying the structure of mussel habitats. Allocation of spatially explicit management tools, notably Territorial User Rights in Fisheries and Marine Reserves, together with co-management initiatives, are suggested as relevant tools to fulfill management and conservation objectives for these key bioengineering species.     

Prolonged inundation and ecological changes in an Avicennia mangrove: implications for conservation and management

The mangrove around Sungei Pemburongunan, just west of Tanjong Batu and Istana Darul Aman in the Brunei-Muara District, is unique in that it contains the only pure stand of Avicennia marina in Brunei Darussalam. In mid-October, 1990 the mouth of Sungei Pemburongunan was closed due to a natural build-up of a sandbar across it. The mangrove quickly became flooded and adverse effects on the flora and fauna were observed during the following weeks. In mid-December a channel was dug across the sand bar to reduce the flooding and normalise the ecology. Some of the dying Avicennia and Lumnitzera have since recovered but others such as Acrostichum and Casuarina have not. Avicennia showed some interesting responses to prolonged inundation. Many of the Avicennia that had flowered during the flood produced seedlings which are now well rooted and 40–80 cm in height. The survival of large numbers of these seedlings is attributed to the floor-related decrease in the number of grapsid and sesarmid crabs which predate on them. The crab and mollusc populations have largely recovered. Unlike periodic short-term flooding which does not seem to have any apparent adverse affect on the ecosystem, prolonged inundation can result in the loss of the Avicennia and its associated flora and fauna. Thus, fragile mangrove ecosystems such as this need to be monitored and managed closely.This work demonstrates that contrary to conventional wisdom, human intervention and management can be beneficial to more fragile ecosystems, which could otherwise succumb to natural processes. Furthermore, it highlights the importance of the dynamic nature of the environment which should be considered in management and conservation programmes.     

Using probability of occurrence to assess potential interaction between wind farms and a residual population of golden eagle Aquila chrysaetos in NW Spain

We evaluate the areas with potential negative impacts in a golden eagle population derived of the development of wind farms. At present, the entire golden eagle Galician population (5–6 pairs) is located within an area of about 2,000 km². Grid squares of 10 × 10 km UTM in the province were scored for current and future wind turbine density and probability of occurrence of golden eagle. This probability was obtained using cartographic models of habitat selection for two different historic periods. Potential risk index (PRI) was calculated for each grid square by multiplying the wind turbine density score by the probability of occurrence score. With the PRIs obtained a cartographic model of potential impact of wind farms on the golden eagle population was constructed. No significant correlation was observed between current wind turbine density and the probability of occurrence of golden eagle. A significant positive correlation was observed between current and future wind turbine density and the probability of occurrence of golden eagle. The areas with highest potential risk are eastern and the central mountains of Ourense where the species breeds. The risk model presented could be applied to future wind farm proposals and monitor potential interactions of golden eagles with wind farms in the Province of Ourense.     

Dynamics and foraging behaviour of adult hornet robberflies, Asilus crabroniformis: implications for conservation management

Mark resighting studies of the hornet robberfly, Asilus crabroniformis, were carried out during the flight seasons of 1999 and 2000 on agricultural land on the Chilterns in Oxfordshire, UK. Six patches of land were identified which contained characteristics thought to be attractive to hornet robberflies. One hundred and twenty eight adults were marked in 1999 and 257 in 2000. Marking was carried out on one of the patches, but resighting observations were collected from all six sites. The daily population sizes were estimated using the Jolly-Seber method. The daily population size peaked between 50 and 72 from 23 August until 13 September in 2000. This was very similar to the peak population size of between 50 and 74 estimated for 1999. Adults were found to be capable of living for nearly 5 weeks. The maximum linear distance from the point of marking that any individual moved across the study site was 625 m, but some individuals moved over 400 m in a single day. Unsuitable habitat (suburban gardens and a main road) did not present a barrier to dispersal. Males were more likely than females to loiter in sites peripheral to the breeding site, whilst females seemed to be more tied to the breeding site. Most adults were caught from dung piles, but insects avoided fresh dung and preferred instead dung that was well into the process of drying out. A variety of insect species were taken as prey, including many beetles and flies. The findings of the study are discussed in relation to the management of the landscape to enhance the long-term prospects of the hornet robberfly in the UK, and to achieve the UK Biodiversity Action Plan target for this species.     

Stochastic models for mainland-island metapopulations in static and dynamic landscapes

This paper has three primary aims: to establish an effective means for modelling mainland-island metapopulations inhabiting a dynamic landscape; to investigate the effect of immigration and dynamic changes in habitat on metapopulation patch occupancy dynamics; and to illustrate the implications of our results for decision-making and population management. We first extend the mainland-island metapopulation model of Alonso and McKane [Bull. Math. Biol. 64:913–958, 2002] to incorporate a dynamic landscape. It is shown, for both the static and the dynamic landscape models, that a suitably scaled version of the process converges to a unique deterministic model as the size of the system becomes large. We also establish that, under quite general conditions, the density of occupied patches, and the densities of suitable and occupied patches, for the respective models, have approximate normal distributions. Our results not only provide us with estimates for the means and variances that are valid at all stages in the evolution of the population, but also provide a tool for fitting the models to real metapopulations. We discuss the effect of immigration and habitat dynamics on metapopulations, showing thatmainland-like patches heavily influence metapopulation persistence, and we argue for adopting measures to increase connectivity between this large patch and the other island-like patches. We illustrate our results with specific reference to examples of populations of butterfly and the grasshopperBryodema tuberculata.     

The distribution and prevalence of helminths,coccidia and blood parasites in two competing species of gecko: implications for apparent competition

Across the Pacific the invading gecko species Hemidactylus frenatus has competitively displaced the resident gecko species Lepidodactylus lugubris in urban/surburban habitats. Do parasites enhance, inhibit, orhave no effect on this invasion? Parasites can confer an advantage to an invading species when the invader (1) introduces a new parasite to a resident species that has a greater detrimental effect on the resident than the invader, (2) is less susceptible to endemic parasites than the resident, and/or (3) increases the susceptibility of the resident to parasites. Conversely, parasites may protect a resident against invasion when endemic parasites have a greater impact on the invader than the resident. We screened more than one thousand H. frenatus and L. lugubris in areas of sympatry and allopatry from 28 islands and 5 sites on mainland Asia for a broad array of blood parasites, coccidia and helminths in order to evaluate the potential for parasites to affect their interaction. We found that 1) There were no parasites which appear to protect L. lugubris against invasion by H. frenatus. 2) H. frenatus does not introduce the same parasite to L. lugubris in every location where the two come in to contact, but probably has introduced different parasites in different locations. L. lugubris also seems to have introduced at least one parasite to H. frenatus. 3) The prevalence of parasite species shared by the two hosts is generally higher in H. frenatus; however, prevalence is determined by many factors and cannot be directly translated as susceptibility. We discuss the implications of this difference in prevalence for the Red Queen hypothesis. 4) The prevalence of the cestode Cylindrotaenia sp. is significantly higher in L. lugubris that are sympatric with H. frenatus than those which are allopatric.     

Variation in life-cycle between three rare and endangered floodplain violets in two regions: implications for population viability and conservation

We studied the demography of Viola elatior, V. pumila, and V. stagnina, three rare and endangered Central European floodplain species, to (i) analyse variation in life-cycles among congeners and between regions (Dyje-Morava floodplains, Czech Republic; Upper Rhine, Germany), (ii) to define sensitive stages in the life-cycles, and (iii) to identify possible threats for population viability and species conservation. Matrix models were based on the fate of marked individuals from a total of 27 populations over two years. We analysed population growth rate (λ), stage distribution, net reproductive rate (R ₀), generation time, age at first reproduction, and elasticity and calculated a life table response experiment (LTRE). Most populations were declining and λ did not differ between species or regions during the observed interval. Despite higher probabilities for survival and flowering in the Dyje populations, R ₀ was higher in the Rhine populations. Also other demographic traits showed consistent differences between regions and/or species. Complex life-cycles and large variation in λ precluded unequivocal identification of sensitive stages or vital rates for conservation. Variation between regions may be a consequence of differences in habitat quality. Our results suggest that deterministic processes such as reduced management, succession, habitat destruction, and lack of disturbance through reduced or eliminated flooding present the strongest threat for the viability and persistence of populations of the three floodplain violets as compared with stochastic processes. However, the persistent seed bank of the species may buffer populations against environmental variation and represents a reservoir for recovery after resumption of suitable land-use management.     

Modelling habitat use and distribution of golden eagles <Emphasis Type="Italic">Aquila chrysaetos</Emphasis> in a low-density area of the Iberian Peninsula

We analyse the current situation of the Golden eagle (Aquila chrysaetos) in the region of Galicia in NW Spain. At present, the entire Galician population (five pairs) is located within an area of about 2000 km² in the province of Ourense. To identify high-priority areas for golden eagle conservation, we derived predictive models of habitat suitability using logistic regression and a Geographic Information System (GIS). Specifically, to model the distribution of the breeding population we considered topographic features, land use and degree of humanization, using a 10 × 10 km grid. Presence/absence of golden eagle nests was used as the dependent variable; analyses were performed both considering current nesting areas and considering old nesting areas (1960s and 70s). At the spatial scale considered, the best predictors of habitat suitability for breeding were topographical variables indicative of rugged relief. For current nesting areas the most parsimonious model included maximum altitude. We consider that the predictive models obtained may be of use for the monitoring and conservation management of the golden eagle population in this region. Conservation problems associated with habitat constraints such as food supply, availability of nesting sites, changes in land use and human disturbance are discussed.     

Geoglossaceous fungi in Slovakia: rare and new taxa for the territory

Field research on grassland fungi in Slovakia resulted in collection of several rare fungi, including also geoglossaceous taxa, such as Microglossum viride (5 sites), Trichoglossum hirsutum (13 sites), Trichoglossum walteri (5 sites), Trichoglossum variabile (1 site), Microglossum olivaceum (2 sites), Thuemenidium atropurpureum (1 site). Last three species are new for Slovakia.     

Marine invasive species: validation of citizen science and implications for national monitoring networks

Approximately 1,000 volunteers assessed the presence of invasive (Carcinus maenas and Hemigrapsus sanguineus) and native crabs within the intertidal zone of seven coastal states of the US, from New Jersey to Maine. Identification of crab species and determination of the gender of the observed crabs was documented at all 52 sites across a 725-km coastal transect. Using quantitative measures of accuracy of data collected by citizen scientists, a significant predictor of a volunteer’s ability was determined and eligibility criteria were set. Students in grade three and seven had the ability to differentiate between species of crabs with over 80% and 95% accuracy, respectively. Determination of gender of the crabs was more challenging and accuracy exceeded 80% for seventh grade students, while 95% accuracy was found for students with at least 2 years of university education. We used the data collected by citizen scientists to create a large-scale standardized database of the distribution and abundance of the native and invasive crabs. Hemigrapsus sanguineus dominated the rocky intertidal zone from Sandy Hook, New Jersey to Boston Harbor, Massachusetts while C. maenas dominated the northern extent of the sampled coastline. A citizen scientist of this monitoring network detected a range expansion of H. sanguineus. We identified obstacles to creating a national monitoring network and proposed recommendations that addressed these issues.     

Nocturnal foraging by great skuas Stercorarius skua: implications for conservation of storm-petrel populations

At St Kilda, Outer Hebrides, a large colony of great skuas Stercorarius skua feed extensively on one of the largest colonies of Leach’s storm-petrels Oceanodroma leucorhoa in Europe, but little is known about the dynamics of this predator–prey system. Recently published population estimates of storm-petrels make it possible to estimate the impact of skua predation for the first time. Although skuas in the southern hemisphere catch petrels attending breeding colonies at night, it is not known whether congeners in the northern hemisphere also forage during the hours of darkness. We found (using radio-transmitters) that skuas regularly forage at night and (using light intensifying equipment) observed them catching storm-petrels at night. However, skuas also foraged during daylight hours, and it is unknown whether they might also catch storm-petrels at sea. Data on diet composition reveals that the proportion of storm-petrels in skua diet declined between 1996 and 1997, but remained constant thereafter. Although a large proportion of the storm-petrel prey is likely to consist of non-breeders, numbers consumed suggest that breeders and an unknown quantity of transients may also been eaten. The numbers of storm-petrels eaten are not sustainable and may result in substantial long-term population declines. Under current conditions, maintenance of large populations of both Leach’s storm-petrels and great skuas at St Kilda appears to be mutually exclusive.     

Behaviour and resource use of two competing vole species under shared predation risk

Indirect interaction between two competing species via a shared predator may be an important determinant of population and community dynamics. We studied the effect of predation risk imposed by the least weasel Mustela nivalis nivalis on space use, foraging and activity of two competing vole species, the grey-sided vole Myodes rufocanus, and the bank vole Myodes glareolus. The experiment was conducted in a large indoor arena, consisting of microhabitat structures providing food, shelter, trees for refuge and separated areas with high and low predation risk. Voles were followed for 5 days: 2 days before, 1 day during and 2 days after the presence of weasel. Our results suggest an effect of weasel presence on the vole community. Voles of both species shifted their activity from risky to less risky areas, climbed trees more often and were less active. Seed consumption was not affected by weasel presence. The time spent in the risky and less risky area did not differ between species, but bank voles spent more time in trees than grey-sided voles. Males of both species were more exposed to predation risk than females, i.e. generally spent more time in the risky area. Proportion of time spent in the risky area, the use of area, trees and food stations were sex dependent. Activity and use of trees were species dependent. We found no evidence for despotic distribution between our two species, although bank voles seemed to be more affected by coexistence, since they lost weight during the experiment. Based on our results we conclude that predator response was largely similar between species, while the sex-specific responses dominated. Besides a stronger escape response in the bank vole, the strongest individual differences were sex specific, i.e. males were more prone to take risks in space use and activity.     

The role of pigeon consumption in the population dynamics and breeding performance of a peregrine falcon (<Emphasis Type=Italic>Falco peregrinus</Emphasis>) population: conservation implications

In this paper, we describe and analyze the diet of peregrine falcons during a long-term period (1982–2002). A combination of direct observations of prey brought to nests, prey remains, and regurgitated pellets were used to calculate diet diversity and dietary overlap between peregrine pairs. We also examined diet diversity in relation to breeding performance. All peregrine pairs fed mainly on birds, with pigeons the most common prey. An increase in pigeon availability has been associated with both an increase in population size and an increase in breeding performance (measured as the average productivity of pairs per year) of a small peregrine falcon population in eastern Spain. Average productivity was lower when dietary breadth was higher. We speculate that our results were the synergistic effect of declining persecution and increased pigeon availability through increased popularity of keeping racing pigeons. There is a conflict of interests between pigeon fanciers and peregrine conservation. As a consequence, this could result to an increased risk of mortality by direct persecution. In accordance with this, conservation measures aimed at preventing direct persecution are encouraged.     

The genetic status and conservation management of two cultivated bulb species extinct in the wild: Tecophilaea cyanocrocus (Chile) and Tulipa sprengeri (Turkey)

Tecophilaea cyanocrocus and Tulipasprengeri are both extinct in the wild as aresult of overharvesting by commercialcollectors. Stocks of both species survive incultivation in amateur collections, commercialnurseries and botanic garden collections.Whilst both species share a similarconservation history, the distribution ofgenetic diversity within cultivated materialwas unknown. To support the long-termconservation of both species the geneticdiversity of the surviving stocks was assessedusing amplified fragment length polymorphisms(AFLPs). This study revealed different geneticstructures for the two bulb species. The Kewcollections of T. cyanocrocus, originallyobtained from a commercial nursery, VanTubergen, are genetically highly uniform andthe addition of samples from other collectionshas dramatically increased the level ofvariation. In contrast, the collections ofT. sprengeri held at Kew since the early20th century include representativegenotypes covering the whole range of geneticvariation found in this species and areprobably the source of all other cultivatedmaterial. The results are discussed in relationto the management of these species to ensuretheir continued survival in cultivation.     

Characteristics of usurped colonies in the subtropical paper wasp,Ropalidia fasciata (Hymenoptera: Vespidae)

Summary Nest usurpation in the subtropical paper waspRopalidia fasciata was studied in Okinawa, southern Japan. Eight of 14 usurpations occurred around the first worker emergence (within 3 days before and 3 days after the emergence). A discriminant analysis showed that the usurpers preferred colonies that had fewer adult females and fewer cells but abundant pupae, compared with non-usurped colonies in the study area on same dates. This suggests that usurpers can assess the development of other colonies and then select a nest that is easy to usurp (fewer females) but has valuable resources (abundant pupae).     

Abundance,distribution, and territory areas of rock-dwelling Lake Tanganyika cichlid fish species

Lake Tanganyika, the second-oldest and second-deepest lake in the world, harbors an impressive cichlid fish fauna counting about 250 endemic species that are characterized by a great level of ecological, morphological, and behavioral specialization. This study describes and compares cichlid fish communities at two rocky shores with differential human impact in the south of Lake Tanganyika. Species inventories and depth-dependent abundances were elaborated. About 41 and 46 sympatric cichlid species were recorded in the two study sites, respectively. Variabilichromis moorii was the most abundant species (29–60% of total number of fishes), followed by Aulonocranus dewindti (3–19%), Tropheus moorii (12%), Ophthalmotilapia ventralis (4–10%), Eretmodus cyanostictus (6–11%), and Cyathopharynx furcifer (0.01–9%). All other species had abundances below 5%. It further emerged that large cichlids such as Petrochromis species, Cyathopharynx furcifer, and Lobochilotes labiatus were very rare at one location, with frequencies of 0.55% or less. Territorial sizes of three particularly abundant species, Variabilichromis moorii, Aulonocranus dewindti, and Tropheus moorii, were assessed by behavioral observations. We distinguished between territorial core areas and total defended area, yielding average core areas between 0.4 (V. moorii) and 1.6 m² (T. moorii), and total defended areas averaging for each species between 1.6 (V. moorii) and 5.0 m² (A. dewindti) with no significant differences between the two study sites. The data on individual densities are also relevant for evolutionary studies, in that they allow more accurate calculations of effective population sizes.