Does land irrigation actually reduce foraging habitat for breeding lesser kestrels? The role of crop types

The lesser kestrel is a Globally Threatened Species which large decline has been related to recent agricultural changes in European pseudo-steppes. Irrigation is considered as one of the major threats for this and other steppe birds, but the actual effects of irrigation on foraging habitat selection have been scarcely examined. We studied the selection of traditional dry cereal farming and irrigated habitats by foraging lesser kestrels during the breeding cycle, paying especial attention to possible differences among crop types. Field margins were the scarcest but the most positively selected habitat, and different stages of cereals cultivated following traditional practices were selected depending on the breeding and agriculture cycles. Effects of irrigation were dual. While irrigated maize and other crop types were avoided, alfalfa was used in proportion to its availability and later highly selected after harvesting. Moreover, field margins in irrigated land were selected in a similar way than in traditional dry farmland. Therefore, although maintaining low-intensity farming is still the main recommendation for this species, new management options arise when social pressure makes irrigation unavoidable. Further agri-environmental schemes in these circumstances should thus promote cultivation of alfalfa with a low input of biocides while avoiding maize, together with increasing field margins, to make compatible irrigation with lesser kestrel conservation.     

Identifying the effectiveness and constraints of conservation interventions: A case study of the endangered lesser kestrel

The recognition of the rapid and ongoing biodiversity loss has been leading to increasing conservation efforts. To maximise conservation success it is important to evaluate when interventions are likely to be effective. In Portugal, previous research identified that lack of suitable nest-sites was limiting the populations of the endangered lesser kestrel (Falco naumanni). Consequently, a massive provisioning of artificial nest-sites and the implementation of a medium term monitoring scheme was established. Our study showed that artificial nest-site provisioning is an effective measure in mitigating the lack of traditional sites. The lesser kestrel population increased from 155–158 pairs in 1996 to 527–552 in 2007, with 52% breeding in artificial nests. We investigate the factors affecting colony growth and found that colony growth was positively affected by the provisioning of artificial nests but negatively affected by predation rate and human disturbance. Between 2003 and 2007, mean colony growth was estimated at 6.46 ± 1.86 pairs for colonies where artificial nests were provided and −0.69 ± 0.5 pairs in colonies without nest-site provisioning. Moreover, predation rate was significantly lower in artificial nests than in natural ones and, although the number of competitor pairs in lesser kestrel colonies increased, the proportion of nests occupied by competitor species decreased. High risk of collapse and restoration of rural abandoned farmhouses may jeopardize the future of the lesser kestrel in Portugal. Nest-site provisioning and the establishment of a protection status for buildings holding colonies are likely the most effective means to guarantee the long-term survival of this species in the area.     

Use of monitoring data and population viability analysis to inform reintroduction decisions: Peregrine falcons in the Midwestern United States

The peregrine falcon (Falco peregrinus anatum) has not yet recolonized natural cliff sites in Illinois and much of the lower Midwestern US, and remains restricted to urban areas. We constructed a landscape-linked population viability analysis using RAMAS/GIS software to compare possible reintroduction strategies for the species. Habitat-specific (i.e. cliff and urban) demographic parameters such as survival, fecundity, and dispersal rates were derived from the Midwest Peregrine Society Database for peregrines in the central Mississippi River region during 1982-2006. We simulated a base scenario of no reintroduction and 18 models of reintroduction with varying cohort sizes, supplementation schedules, and number of reintroduction sites, and used the Lake Superior population to test our model. Our analysis indicated that even without reintroductions in Illinois, the peregrine population in the lower Midwestern region is slowly increasing and is not likely to go extinct. Recolonization of cliff sites in southern Illinois likely will occur via dispersal from urban populations, however further research on dispersal rates between urban areas and cliffs is needed. Analysis indicated that the most cost-effective reintroduction strategy would be priced at approximately $280,000 and would result in only two additional breeding pairs compared to the no-action scenario. Thus, funds would be more effectively used in other management efforts such as habitat preservation. This study provides an example of how post-release monitoring can be used to inform future reintroduction plans.     

Adapting conservation efforts to face climate change: Modifying nest-site provisioning for lesser kestrels

Adaptation to climate change has recently become a crucial element on the climate change policy agenda as it is now recognized that even the most stringent mitigation efforts may not arrest the effects of climate warming. The ecological impacts and costs of predicted weather-related extreme events, such as extreme temperatures, are not fully understood and may present unexpected challenges to conservationists that require solutions. In Portugal, provisioning of artificial nests has been the main driver of the spectacular increase in the endangered lesser kestrel population. Nevertheless, atypically high temperatures recorded during the 2009 breeding season coincided with a mortality of 22% of surveyed chicks in provided nests. Hot days did not affected prey delivery rates to the nestlings, suggesting that the die-off was due to chicks’ acute dehydration. Chick mortality was significantly higher amongst younger individuals. Within survivors, physiological costs of high temperatures significantly affected chick growth and body condition at fledging. Nest-site microclimate was influenced by nest-type and compass orientation: wooden nest-boxes attained the highest temperatures, exceeding 55 °C when facing south, so explaining the recorded higher mortality, lower growth rates and lower fledging body condition among broods in these nests. Simulated scenarios of global warming with increasing occupation rate of artificial nests due to reductions in alternatives predicted a reduction in population growth rate. In the worst scenario, with a 100% occupancy of nest-boxes, the population growth would decline on average 7% per year. The impact of high temperatures on lesser kestrel breeding success highlights a need for actions to modify and research to adapt conservation efforts and future planning to account for climate change.     

Badger hair in shaving brushes comes from protected Eurasian badgers

The Eurasian badger (Meles meles) is included in Appendix III of the Bern Convention and protected by national laws in many European countries. Badger hair is used to manufacture luxury shaving brushes, although it is frequently argued that the hog badger (Arctonyx collaris), which in Europe is an introduced and unprotected species, is the origin of the hair used. We applied an extraction protocol to recover DNA from the unrooted hair of shaving brushes obtained from commercial companies in The Netherlands and Spain. The tested brushes originated from The Netherlands, Spain, France, Italy and the United Kingdom where the Eurasian badger is a protected species. We sequenced 191 bp of the mitochondrial DNA control region and 170 bp of the cytochrome b gene and compared the sequences obtained with Eurasian badger and hog badger reference sequences of the same mitochondrial DNA regions obtained in our laboratory and from GenBank. Sequences obtained from four shaving brushes were clearly hog badger sequences, whereas four sequences clustered with Eurasian badger sequences of both European and Asian origins. One of the shaving brushes made of Eurasian badger was produced in France, where it is legal to capture or trade the species under certain conditions. The remaining three brushes originated from The Netherlands, where it is illegal to possess, sell, transport or use for commercial purposes dead Eurasian badgers or products derived from them.     

Persistence of Gunnison’s prairie dog colonies in Arizona, USA

Although the five species of prairie dogs (Cynomys spp.) are recognized as important components of grassland ecosystems in western North America, they have experienced major population declines due to poisoning, outbreaks of sylvatic plague, recreational shooting, and habitat conversion. From May 2000 to October 2001, we investigated 270 colonies of Gunnison’s prairie dog (Cynomys gunnisoni) in Arizona. Because these colonies were classified as active in previous surveys (1987, 1990-1994, 1998), we were able to examine their persistence. Most (70%) of the colonies became inactive between the initial and recent surveys, with colony extinctions spanning our study area. Colony persistence was positively associated with the persistence of the nearest neighboring colony but was not associated with major vegetation type, distance to nearest neighboring colony, or initial size of the colony. The amount of area occupied by individual colonies varied between surveys, sometimes dramatically. We found little evidence that the reduction in active colonies was due to poisoning, recreational shooting, or habitat conversion. Rather, direct and indirect evidence suggest plague is the primary factor negatively impacting Gunnison’s prairie dog populations in Arizona. Currently, there is no way to control or prevent plague outbreaks in Gunnison’s prairie dog populations. To mitigate the effects of localized plague outbreaks on the overall population of this species, we suggest that Gunnison’s prairie dog be reintroduced to public lands throughout its historical range.     

Genetic structure, population dynamics, and conservation of Black caiman (Melanosuchus niger)

Microsatellite DNA polymorphisms were screened in seven populations of the largest Neotropical predator, the Black caiman Melanosuchus niger (n = 169), originating from Brazil, French Guiana and Ecuador. Eight loci were used, for a total of 62 alleles. The Ecuadorian population had the lowest number of alleles, heterozygosity and gene diversity; populations of the Guianas region exhibited intermediate diversities; highest values were recorded in the two populations of the Amazon and Rio Negro. During the last century Melanosuchus populations have been reduced to 1-10% of their initial levels because of hunting pressure, but no strong loss of genetic diversity was observed. Both the inter-locus g-test and the Pk distribution suggested no recent important recovery and/or expansion of current populations. On a global scale, the inter-population variation of alleles indicated strong differentiation (F_ST = 0.137).Populations were significantly isolated from each other, with rather limited gene flow; however, these gene flow levels are sufficiently high for recolonization processes to effectively act at regional scales. In French Guiana, genetic structuring is observed between populations of two geographically close but ecologically distinct habitats, an estuary and a swamp. Similar divergence is observed in Brazil between geographically proximate “black water” and “white water” populations. As a consequence, the conservation strategy of the Black caiman should include adequate ecosystem management, with strong attention to preservation of habitat integrity. Distribution of genetic diversity suggests that current populations originated from the central Amazonian region. Dispersal of the species may thus have been deeply influenced by major climatic changes during the Holocene/Pleistocene period, when the Amazonian hydrographic networks were altered. Major ecological changes such as glaciations, marine transgressions and a hypothesized presence of an Amazonian Lake could have resulted in extension of Black caiman habitats followed by isolation.     

Reed harvest and summer drawdown enhance bittern habitat in the Camargue

The vulnerable Eurasian bittern Botaurus stellaris has recently benefited from conservation actions in several European countries. The Camargue in Mediterranean France holds 8000 ha of reed marshes and 50% of the French bittern population estimated at 300-350 booming males. Although reed cutting in Europe is a current practice, we provide the first analyses on habitat selection relative to reed exploitation. The contribution of reed harvesting and water management was assessed at a fine scale (digitized aerial photographs of 50-cm resolution) based on multi-modelling data analyses. GLMs applied to random and bittern points of 50-m radius showed that bitterns preferred areas with less than 10% open water enclosing 1-year reeds. Only in harvested reedbeds had the water management a significant impact on habitat selection, with bitterns avoiding areas dried during less than two months and flooded since less than 8 months. Water edge played a role in non-harvested reeds only, with bittern seeking for areas with the highest ratio water edge to open water. Although reed cutting is generally considered as detrimental in the short term, two 4-year experiments showed a marked increase in bitterns the first spring after cutting was interrupted. Based on these results, we propose various management scenarios that conciliate economic constraints of reed harvesters and protection of Eurasian bittern populations.     

Comparison of survival rates of captive-reared and wild-bred Mauritius kestrels (Falco punctatus) in a re-introduced population

Re-introduction is a technique widely used in the conservation of threatened bird species. With advances in aviculture the use of captive-produced individuals as the release stock is becoming more commonplace, and ideally, survival of captive-produced, released individuals should be no different from their wild-bred counterparts. During the late 1980s the Critically Endangered Mauritius kestrel (Falco punctatus) was successfully re-introduced into the Bambous mountain range, Mauritius, some 30 years after its local extinction. Between 1987 and 2001 the developing population was closely monitored enabling us to construct re-sighting histories for 88 released and 284 wild-bred kestrels. We used age-structured models in the survival analysis software program MARK to determine if an individual's origin influenced its subsequent survival. Our analysis indicated no compelling evidence for reduced survival among juvenile captive-reared and released individuals, relative to their wild-bred counterparts, across the majority of cohorts and only limited evidence of a cohort-specific effect. This study illustrates that despite the lack of a formal experimental approach it is still feasible to conduct an assessment of re-introduction outcomes and techniques.     

Re-establishment of suppressiveness to soil- and air-borne diseases by re-inoculation of soil microbial communities

The aim of this study was to investigate the potentials and limitations in restoring soil suppressiveness in disturbed soils. Soils from three sites in UK and Switzerland (STC, REC, THE) differing in their level of suppressiveness to soil-borne and air-borne diseases were γ-irradiated and this soil matrix was re-inoculated with 1% (w/w) of either parent native soil or native soil from the other sites (‘soil inoculum’). Suppressiveness to air-borne and soil-borne diseases was quantified by means of the host-pathogen systems Lepidium sativum (cress)-Pythium ultimum, an oomycete causing root rot and seedling damping-off, and Arabidopsis thaliana-Hyaloperonospora parasitica, an oomycete causing downy mildew. Soil microbial biomass, activity and community structure, as determined by phospholipid fatty acid (PLFA) profiles, were measured in native, γ-irradiated, and re-inoculated soils. Both, L. sativum and A. thaliana were highly susceptible to the pathogens if grown on γ-irradiated soils. Re-inoculation completely restored suppressiveness of soils to the foliar pathogen H. parasitica, independently of soil matrix or soil inoculum, whereas suppressiveness to P. ultimum depended on the soil matrix and, to a lesser extent, on the soil inoculum. However, the soil with the highest inherent suppressiveness did not reach the initial level of suppressiveness after re-inoculation. In addition, native microbial populations as defined by microbial biomass, activity and community structure, could not be fully restored in re-inoculated soils. As for suppressiveness to P. ultimum, the soil matrix, rather than the source of soil inoculum was identified as the key factor for re-establishing the microbial community structure. Our data show that soils do not or only slowly fully recover from sterilisation by γ-irradiation, indicating that agricultural soil management practices such as soil fumigation or heat treatments frequently used in vegetable cropping should be avoided.     

Phylogeography and conservation of the populations of Zootoca vivipara carniolica

The lizard Zootoca vivipara has both oviparous and viviparous populations which belong to distinct clades. This study aims to elucidate the geographic distribution, phylogeography and conservation priority of the oviparous subspecies, Zootoca vivipara carniolica, that has recently been identified in Slovenia. We studied seven Slovenian populations, two northeastern Italian populations and five northwestern Italian populations. The seven cytochrome b haplotypes that we identified from the Slovenian and Italian oviparous populations form a monophyletic basal clade. The high homogeneity of the Slovenian and northeastern Italian populations (nucleotide diversity π=0.06%) is a striking contrast with the pattern observed in northwest Italy where each of the five populations studied presents a private haplotype (π=1.03%). The results obtained suggest that all the extant lineages of Z. v. carniolica have originated in an Italian refuge. The reproductive and phylogenetic distinctiveness of Z. v. carniolica clearly justifies conservation of its populations, especially in Italy where the highest genetic diversity and the most ancestral haplotype were observed.     

Conserving marginal populations of the food plant (Impatiens noli-tangere) of an endangered moth (Eustroma reticulatum) in a changing climate

Impatiens noli-tangere is scarce in the UK and probably only native to the Lake District and Wales. It is the sole food plant for the endangered moth Eustroma reticulatum. Significant annual fluctuations in the size of I. noli-tangere populations endanger the continued presence of E. reticulatum in the UK. In this study, variation in population size was monitored across native populations of I. noli-tangere in the English Lake District and Wales. In 1998, there was a crash in the population size of all metapopulations in the Lake District but not of those found in Wales. A molecular survey of the genetic affinities of samples in 1999 from both regions and a reference population from Switzerland was performed using AFLP and ISSR analyses. The consensus UPGMA dendrogram and a PCO scatter plot revealed clear differentiation between the populations of I. noli-tangere in Wales and those in the Lake District. Most of the genetic variation in the UK (H_T=0.064) was partitioned between (G_ST=0.455) rather than within (H_S=0.034) regions, inferring little gene flow occurs between regions. There was similar bias towards differentiation between metapopulations in Wales, again consistent with low levels of interpopulation gene flow. This contrasts with far lower levels of differentiation in the Lake District which suggests modest rates of gene flow may occur between populations. It is concluded that in the event of local extinction of sites or populations, reintroductions should be restricted to samples collected from the same region. We then surveyed climatic variables to identify those most likely to cause local extinctions. Climatic correlates of population size were sought from two Lake District metapopulations situated close to a meteorological station. A combination of three climatic variables common to both sites explained 81-84% of the variation in plant number between 1990 and 2001. Projected trends for these climatic variables were used in a Monte Carlo simulation which suggested an increased risk of I. noli-tangere population crashes by 2050 at Coniston Water, but not at Derwentwater. Implications of these findings for practical conservation strategies are explored.     

Field survival of the phytostimulator Azospirillum lipoferum CRT1 and functional impact on maize crop, biodegradation of crop residues, and soil faunal indicators in a context of decreasing nitrogen fertilisation

Heavy nitrogen fertilisation is often implemented in maize cropping systems, but it can have negative environmental effects. Nitrogen-fixing, phytohormone-producing Azospirillum plant growth-promoting rhizobacteria (PGPR) have been proposed as crop inoculants to maintain high yield when decreasing nitrogen fertilisation. In this context, agronomic and ecological effects of the inoculation of maize seeds with the PGPR Azospirillum lipoferum CRT1 were studied in two consecutive years. The inoculant was recovered from maize at 10⁵ CFU g⁻¹ root or higher. Inoculation enhanced root growth and development based on results of root biomass, rooting depth and/or parameters describing root system architecture, and a transient positive effect on shoot height was observed in the first year. Inoculation did not increase yield, but reducing mineral nitrogen fertilisation had only a minor effect on yield. This suggests that the lack of positive effect of the PGPR on yield was due to the fact that the whole field was heavily fertilised in years prior to the start of the experiment. Soil nitrogen levels decreased during the 2 years of the study, and the inoculant had no effect on residual soil nitrogen levels at harvest. Inoculation had no impact on Fusarium symptoms and concentration of the mycotoxin deoxynivalenol in maize kernels, but both were influenced by the interaction between inoculation and nitrogen fertilisation level. Inoculation did not influence meso/macrofaunal soil populations, but had a small but significant effect (smaller than the effect of added nitrogen) on decomposition, nitrogen mineralisation and mesofaunal colonisation of maize leaves (in litter bags). Overall, the ecological impact of seed inoculation with the PGPR A. lipoferum CRT1 was small, and its magnitude was smaller than that of chemical nitrogen fertilisation.     

Squirrel poxvirus: Landscape scale strategies for managing disease threat

Squirrel poxvirus (SQPV) is a well-documented example of pathogen-mediated competition between an invasive species, the grey squirrel (Sciurus carolinensis), and a native species, the Eurasian red squirrel (Sciurus vulgaris). SQPV causes disease with high mortality in red squirrels but appears non-pathogenic in grey squirrels. Not all populations of introduced grey squirrels carry the virus, notably those in Scotland and Italy, and the rate of red squirrel replacement by grey squirrels is some twenty times faster in those areas where grey squirrels carry the virus. Here we develop strategies to manage the SQPV disease threat to red squirrels by reference to the largest, designated red squirrel refuge site in England, Kielder Forest (50 000 ha). Using modelling techniques, we identify four main corridors within the buffer zone by which grey squirrels will reach Kielder, initially within two years and in large numbers within 10 years. Assuming that greys will not settle within Kielder because of the unfavourable nature of the spruce habitat, we predict that SQPV disease will burn out at the edges of the forest, although many red squirrels will die. This burn-out is unlikely to be the scenario in other refuge areas where the habitat is more favourable to greys. We conclude that the conservation of red squirrels will depend on minimising contact between red and grey squirrel populations, and we advocate monitoring grey squirrels in corridors within buffer zones around refuge areas, and removing them when detected.     

AFLP fingerprinting of Anchusa (Boraginaceae) in the Corso-Sardinian system: Genetic diversity, population differentiation and conservation priorities in an insular endemic group threatened with extinction

Although several plants endemic to Corsica and Sardinia are included in various redlists, no attempts have been made to analyse their genetic diversity with molecular techniques. Genus Anchusa occurs with seven taxa in either mountain or coastal habitats of the two islands, but the very restricted range and low population size pose these endemisms in a very precarious conservation status. Highly variable markers (AFLP) were therefore used to analyse the patterns and levels of genetic diversity in a sample of 11 populations from the entire range of the group.Results indicate the separation between a mountain genic pool including Anchusa formosa, Anchusa capellii and Anchusa montelinasana, and four groups of coastal accessions. In spite of small size, mountain taxa show low interpopulation differentiation (F_st = 0.02) and relatively high intrapopulation genetic variation (0.365), while coastal accessions showed on average a stronger differentiation (mean F_st = 0.20) and a lower diversity (0.281), possibly due to higher rates of inbreeding. The particularly low levels of variation found in A. sardoa, A. littorea and A. crispa ssp. maritima from the Coghinas bay are likely due to a historical decrease of populations and to bottleneck events caused by loss of habitat and natural stochastic factors on sand dune ecosystems. While habitat maintenance and regulation of grazing by domestic herbivores should be sufficient to ensure the persistence of the mountain endemics, additional actions of in situ and ex situ conservation are needed for the critically endangered coastal species A. sardoa and A. littorea. A. crispa showed a relatively high variation, especially on Corsica. No correlation between population size and genetic variation was found in the latter species, highlighting the importance of the small patches for its conservation. Also, the genetic separation between subspecies crispa and maritima stresses the need of keeping them distinct in redlists and conservation actions on Sardinia.     

Factors affecting population dynamics of Eurasian woodcocks wintering in France: assessing the efficiency of a hunting-free reserve

The Eurasian woodcock Scolopax rusticola is a migratory bird of major importance for hunting, which is susceptible to habitat loss and the stochastic effects of severe winter weather. Conservation issues mostly concerned regulation of hunting, but the efficiency of hunting-free reserves has never been investigated. We studied causes of mortality and survival probabilities of 98 radio-tagged woodcocks in a reserve with no hunting and in an adjoining hunting area in Brittany (France). Predation, mostly by mammalian predators on fields at night, was similar among adults and yearlings, while hunting mortality was more important in yearlings. Overall winter survival probabilities were 0.86 ± SE 0.07 in adults and 0.63 ± SE 0.07 in yearlings. Survival probabilities of both age classes increased as birds spent more time in the reserve. Equality of predation in both reserve and hunting areas suggests an additive mortality due to hunting over the winter. Population matrix models predicted that such low survival probabilities cannot sustain long term viable populations. These results call for caution in the harvesting of woodcock populations wintering in western France and could be a forewarning of a decline. The regulation of hunting by setting bag limits or reducing the length of shooting seasons, or the creation of reserves might be appropriate tools for the sustainable management of woodcock populations.     

The abundance and efficacy of Rhizobium leguminosarum bv. viciae in cultivated soils of the eastern Canadian prairie

For optimum production, the use of commercial rhizobial inoculant on pea (Pisum sativum L.) at seeding is necessary in the absence of compatible rhizobial strains or when rhizobial soil populations are low or symbiotically ineffective. Multiple site experiments were conducted to characterize the abundance and effectiveness of resident populations of Rhizobium leguminosarum bv. viciae (Rlv) in eastern Canadian prairie soils. A survey of 20 sites across a broad geographical range of southern Manitoba was carried out in 1998 and was followed by more intensive study of five of the sites in 1999 and 2000. Appreciable nodulation of uninoculated pea was observed at all sites which had previously grown inoculated pea. However, uninoculated pea grown at two sites, which had not previously grown pea, had negligible nodulation. Likewise, wild Lathyrus sp. and Vicia sp. plants collected from uncultivated areas adjacent to agricultural sites were poorly nodulated. In the more intensively studied sites, there was a tendency towards higher nodulation in pea plants receiving commercial inoculant containing Rlv strain PBC108 across all site-years (e.g., 4.7% in nodulation and 22% in nodule mass), but the effect was significant at only 2 of 10 site-years. Despite a relatively high range of soil pH (6-8), regression analysis indicated that decreasing soil pH resulted in lower nodulation rates. Likewise, electrical conductivity (EC) was correlated to nodulation levels, however the effect of EC was likely more indicative of the influence of soil texture and organic matter than salinity. As with nodulation, commercial inoculation tended to increase above-ground dry matter (DM) and fixed-N (estimated by the difference method) at the early pod-filling stage, but again the effects were significant at only 2 of 10 site-years. Specifically, above-ground DM and fixed-N levels were up to 29 and 51% greater, respectively, in inoculated compared to non-inoculated treatments at these sites. Addition of N-fertilizer at a rate of 100 kg N ha⁻¹ decreased nodulation at almost all site-years (by as much as 70% at one site), but rarely resulted in increases in above-ground DM compared to inoculated plots. The study indicates for the first time that populations of infective, and generally effective strains of Rlv occur broadly in agricultural soils across the eastern Canadian prairie, but that there is a tendency for increased symbiotic efficiency with the use of commercial inoculant.     

Plight of the bumble bee: Pathogen spillover from commercial to wild populations

Pathogen spread or ‘spillover’ can occur when heavily infected, domestic hosts interact with closely-related wildlife populations. Commercially-produced bumble bees used in greenhouse pollination often have higher levels of various pathogens than wild bumble bees. These pathogens may spread to wild bees when commercial bees escape from greenhouses and interact with their wild counterparts at nearby flowers. We examined the prevalence of four pathogens in wild bumble bee populations at locations near and distant to commercial greenhouses in southern Ontario, Canada. Bumble bees collected near commercial greenhouses were more frequently infected by those pathogens capable of being transmitted at flowers (Crithidia bombi and Nosema bombi) than bees collected at sites away from greenhouses. We argue that the spillover of pathogens from commercial to wild bees is the most likely cause of this pattern and we discuss the implications of such spillover for bumble bee conservation.     

Proportion of individuals with anti-Batrachochytrium dendrobatidis skin bacteria is associated with population persistence in the frog Rana muscosa

The emergence of the infectious disease chytridiomycosis is a major factor responsible for amphibian extinctions in pristine habitats. However, some populations coexist with Batrachochytrium dendrobatidis (Bd), the agent of chytridiomycosis, and others go extinct when Bd arrives. Variation of pathogen severity among populations may be explained by differences of antimicrobial skin peptides and anti-Bd skin bacteria. Previous work showed that a population of the frog Rana sierrae had a high proportion of individuals with at least one species of cultured anti-Bd skin bacteria and was coexisting with Bd for more than 6 years. A population of the closely related sister species Rana muscosa had a significantly lower proportion of individuals with anti-Bd bacteria, and the following year, it went extinct due to Bd. We extended previous work to include another sampling of the R. sierrae population coexisting with Bd and found that, although the anti-Bd bacterial community somewhat differed, both populations had a high proportion of individuals with antifungal bacteria. We also included a population of R. muscosa that was naïve of Bd and predicted to go extinct once Bd emerged since that was the fate of neighboring populations. However, the naïve R. muscosa population had a high proportion of antifungal bacteria, which suggested that the population might survive if Bd emerged. Two years later, the population was surviving with Bd endemic. Variation in the proportion of individuals with anti-Bd skin bacteria appears to explain why some populations persist when Bd emerges in a population.     

Molecular markers and a sequence deletion in intron 2 of the putative partial homologue of LEAFY reveal geographical structure to genetic diversity in the acutely threatened legume genus Clianthus

Clianthus is an acutely threatened, bird-pollinated genus endemic to New Zealand, represented in the wild by only one population of C. puniceus and 11 populations of C. maximus, each with very few individuals (typically <10 per population). A limited number of named Clianthus cultivars of indeterminate origin are commonly grown as ornamentals. Genomic DNA from individual Clianthus plants was extracted for genetic diversity analysis using a range of molecular markers, including amplified fragment length polymorphism (AFLP). Data were analysed by the unweighted pair-group method with arithmetic averaging (UPGMA), the generation of Neighbor-Joining trees, and analyses of molecular variance (AMOVA). Genetic distance between wild populations of C. maximus was highly correlated with geographical distance between populations. Sequencing of intron 2 of a putative partial homologue of the floral meristem identity gene LEAFY (CmLFY) revealed a 7 bp deletion that was exhibited homozygously in the more northern populations of C. maximus, and in all individuals tested from the sole population of C. puniceus. This deletion was not exhibited in more southern populations of C. maximus. Further, one geographically intermediate population contained some plants that were heterozygous for the deletion. Parallel analyses of cultivated Clianthus genotypes, more than half of which were also homozygous for the 7 bp deletion, showed that these were not representative of the broad, but threatened, diversity remaining in the wild. It is argued that wild populations of C. maximus are unlikely to have arisen from the escape of plants from cultivation. Conservation effort should focus on the protection and study of the extant plants in these wild populations, rather than on the introduction of disturbance regimes to uncover potential seed banks.