The heat is on: frequent high intensity fire in bracken (<Emphasis Type="Italic">Pteridium aquilinum</Emphasis>) drives mortality of the sprouting tree <Emphasis Type="Italic">Protea</Emphasis><Emphasis Type="Italic">caffra</Emphasis> in temperate grasslands

We examined the effect of fire frequency and intensity on a Protea caffra tree population in the temperate montane grasslands of north-western KwaZulu-Natal, South Africa. We assessed the effect of fire by comparing the population structure of the resprouter P. caffra in discrete bracken (Pteridium aquilinum) patches with that in the surrounding grassland matrix. Fuel biomass did not differ between grassland and bracken, but bracken fuel was significantly drier than grass. Above-ground fire temperatures and fireline intensity, measured by P. caffra char height, were significantly higher in the bracken habitat. Forty-two percent of the P. caffra population in grassland and in bracken persisted by coppice resprouts, having lost their original stem to fire damage. Exposure to higher intensity bracken fire suppressed P. caffra regeneration and caused greater adult mortality compared with trees in grassland. Consequently, the P. caffra population in bracken was skewed towards old age with most trees severely fire damaged. The high incidence of small trees in grassland indicates that a regular fire interval of 2–3 years does not negatively affect regeneration of P. caffra. However, in bracken patches regular high intensity fires cause high mortality among all P. caffra size classes and will ultimately result in local extinction. Bracken thus has the potential to significantly alter tree–grass interactions in these montane grasslands.     

Demographic variation of dwarf birch (<Emphasis Type="Italic">Betula nana</Emphasis>) in communities dominated by <Emphasis Type="Italic">Ledum palustre</Emphasis> and <Emphasis Type="Italic">Vaccinium uliginosum</Emphasis>

The structure and demographic processes were compared in shrub communities to test the effects of vegetation succession on population growth, fecundity and abundance of the dwarf birch (Betula nana L.), which is a rare and endangered plant species in Poland and a glacial relict in Central Europe. The effects of Ledum palustre L. and Vaccinium uliginosum L. were studied in the Linje nature reserve in Chełmińskie Lake District (northern Poland), in three permanent plots on a peat bog. Vegetative growth and reproduction of B. nana were lower in plant communities dominated by L. palustre and V. uliginosum, than in a reference site. Fecundity was also lower, despite the fact that the percentage share of potentially fertile age groups was similar in all study sites. Mortality of ramets was independent of vegetation, both for juvenile and mature stages. The results confirm that B. nana is intolerant of shade, and it is more abundant in vegetation without competitors. Light limitation can lead to its decline, primarily by a decrease in vegetative growth. Sexual reproduction may be negatively affected by shade, but it plays only small role in population growth. Butterfly larvae can destroy inflorescences, and thus contribute to low effectiveness of sexual reproduction. Increasing density of shrubs and trees in peat bogs can reduce the abundance of dwarf birch, and can lead to the extinction of its local populations.     

Population structure and genetic variation in the endangered Giant Kangaroo Rat (<Emphasis Type="Italic">Dipodomys ingens</Emphasis>)

Populations of the endangered giant kangaroo rat, Dipodomys ingens (Heteromyidae), have suffered increasing fragmentation and isolation over the recent past, and the distribution of this unique rodent has become restricted to 3% of its historical range. Such changes in population structure can significantly affect effective population size and dispersal, and ultimately increase the risk of extinction for endangered species. To assess the fine-scale population structure, gene flow, and genetic diversity of remnant populations of Dipodomys ingens, we examined variation at six microsatellite DNA loci in 95 animals from six populations. Genetic subdivision was significant for both the northern and southern part of the kangaroo rat’s range although there was considerable gene flow among southern populations. While regional gene diversity was relatively high for this endangered species, hierarchical F-statistics of northern populations in Fresno and San Benito counties suggested non-random mating and genetic drift within subpopulations. We conclude that effective dispersal, and therefore genetic distances between populations, is better predicted by ecological conditions and topography of the environment than linear geographic distance between populations. Our results are consistent with and complimentary to previous findings based on mtDNA variation of giant kangaroo rats. We suggest that management plans for this endangered rodent focus on protection of suitable habitat, maintenance of connectivity, and enhancement of effective dispersal between populations either through suitable dispersal corridors or translocations.     

Dynamics of isolated <Emphasis Type="Italic">Saponaria bellidifolia</Emphasis> Sm. populations at northern range periphery

Four populations of Saponaria bellidifolia situated at the species’ northern range periphery (Apuseni Mountains, southeastern Carpathians) were monitored over a period of 5 years. They were chosen to represent different habitat types (rocky, fixed screes, open screes and grassy), disturbance regime (fire), and population sizes (categorized as large and small). The reproductive effort was quantified, and matrix models were used to describe the population dynamics and to assess population viability. Saponaria bellidifolia had very stable population dynamics in the harsh and stable abiotic conditions of the outcrops where populations occur. Habitat conditions exerted a notable influence on the species’ population reproductive performance, growth rate, and vital rates, whereas population size and climate did not have a clear-cut effect on the dynamics of the species. Saponaria bellidifolia maintains viable populations in the southeastern Carpathians, at its northern range periphery.     

Potential loss of genetic variability despite well established network of reserves: the case of the Iberian endemic lizard <Emphasis Type="Italic">Lacerta schreiberi</Emphasis>

Although future anthropogenic climate change is recognized as one of the major threats to European species, its implementation during reserve planning has only been started recently. We here describe climate change impacts on the Iberian endemic lizard Lacerta schreiberi expecting serious declines and range reductions due to a loss of suitable climate space in the next future. We apply species distribution models to assess possible future changes in the lizard’s range, identify areas with high extinction risk meriting conservation efforts and analyze whether the Natura 2000 network in its current stage will offer a sufficient protection for the genetically most valuable lineages. Despite a very good coverage and connectivity of the most valuable populations of L. schreiberi with the existing protected sites network, our results predict a strong loss of genetic variability by 2080. Also, two main patterns become evident: While the genetically less diverse north-western populations may be less affected by climate change, the climate change effects on the southern isolates and the genetically most diverse populations within the Central System may be devastating. To improve a successful prospective conservation of L. schreiberi the management of protected sites needs to consider the processes that threaten this species. Furthermore, our study highlights the urgent need to consider climate change effects on evolutionary significant units within the Natura 2000 framework.     

Response of <Emphasis Type="Italic">Arnica dealbata</Emphasis> to climate change,nitrogen deposition,and fire

Predicted changes in climate and increasing nitrogen deposition are likely to have significant impacts on species that have limited distributions or are already experiencing diminished population size. Arnica dealbata (A. Gray, Asteraceae), a listed sensitive species in Yosemite National Park, is endemic to California and has limited distribution within the park boundaries. The objective of this research was to examine the effects of altered precipitation resulting from climate change, increasing nitrogen deposition resulting from pollution, and prescribed fire on A. dealbata. A. dealbata cover significantly increased with increasing snowpack and prescribed fire. Increasing nitrogen deposition negatively affected cover. Our results suggest Yosemite’s A. dealbata populations can thrive even under a changing climate if prescribed fire is frequently applied coupled with increased moisture availability.     

Distribution and habitats of <Emphasis Type="Italic">Phengaris</Emphasis> (<Emphasis Type="Italic">Maculinea</Emphasis>) butterflies and population ecology of <Emphasis Type="Italic">Phengaris</Emphasis><Emphasis Type="Italic">teleius</Emphasis> in China

Many species of the butterfly genus Phengaris are regarded as endangered in many parts of their distribution. Several species are also widely distributed across northern China. Due to land use change and overgrazing, their habitats are declining and many patches have been lost. This paper investigates the distribution and habitats of the Chinese Phengaris species (of the subgenus Maculinea). Shrub-grassland near forests seem the most frequent habitat for Phengaris, while flat open grasslands are mostly over-grazed and thus survival for Phengaris butterflies there seems difficult. Throughout Europe, P. teleius is an endangered species, while there is still no information on its status in China. To improve the knowledge on the population ecology of P. teleius, its population structure, adult behaviour and movement were studied through mark–release–recapture methods in the Qinling Mountains of Taibai County. Eight grassland patches which were potentially suitable were found in the area in 2013. In total, 480 individuals (274 females) were marked, resulting in an overall recapture rate of 16 %. The average daily population size was 44 butterflies (±23 SD) during the adult flight period. Sixty-seven percent of the females and 38 % of the males moved less than 50 m, and 17 % of recaptured females and 38 % of males moved more than 200 m. The mean movement distance was 107 ± 177 m for males and 182 ± 122 m for females. The majority of the recaptures (86 %) were made within the patches, only a few individuals (14 %) moved between patches. Due to human disturbance and destruction, all of the eight potentially suitable patches are becoming smaller and increasingly isolated, thus these populations of P. teleius may face an increasing risk of extinction, which may well be a tip of the iceberg of habitat loss and fragmentation of P. teleius in Taibai County and possibly beyond. Hence we hope our initial study of P. teleius could have positive impacts on the conservation of Phengaris butterflies in China.     

Genetic diversity following demographic recovery in the insular endemic plant <Emphasis Type="Italic">Galium catalinense</Emphasis> subspecies <Emphasis Type="Italic">acrispum</Emphasis>

Galium catalinense (Rubiaceae) is a perennial shrub consisting of two subspecies endemic to California’s Channel Islands: Galium catalinense subsp. catalinense on Santa Catalina Island, and G. catalinense subsp. acrispum, a state-endangered taxon on San Clemente Island. A long history of overgrazing by introduced herbivores has contributed to population declines in G. catalinense subsp. acrispum. We surveyed 12 populations throughout the taxon’s range for genetic variation using eight polymorphic microsatellite loci to determine the genetic impact of this demographic bottleneck. At the taxon level, 65 alleles were identified with an average of 8.1 alleles per locus, although many alleles were rare; the effective number of alleles per locus averaged 2.6. Expected heterozygosity was 0.550. Individual populations had between six and eight polymorphic loci, with expected heterozygosities ranging from 0.36 to 0.60, and effective numbers of alleles ranging from 1.8 to 3.5 per locus. Populations fell into three or four genetic clusters, depending on type of analysis, which may represent refugia where the populations persisted during intense herbivory. There is little evidence of genetic bottlenecks or substantial inbreeding within populations. These findings, coupled with indications of recent migration between populations, suggest that G. catalinense subsp. acrispum is currently unlikely to be endangered by genetic factors, but small population sizes make the taxon vulnerable to future loss of genetic diversity. Management strategies based on these genetic data, population sizes, and the spatial distribution of populations are discussed.     

Assessment of hybridisation between the endangered Chatham Island black robin (<Emphasis Type="Italic">Petroica traversi</Emphasis>) and the Chatham Island tomtit (<Emphasis Type="Italic">Petroica macrocephala chathamensis</Emphasis>)

Hybridisation between an endangered species and a more common species can facilitate population decline and extinction of the endangered species due to wasted reproductive effort, outbreeding depression and/or swamping of alleles due to widespread or complete admixture. The Chatham Island black robin (Petroica traversi) is an endangered songbird species, which was reduced to only five individuals in 1980. Intensive cross-fostering, whereby black robin offspring were placed into nests of the closely related Chatham Island tomtit (Petroica macrocephala chathamensis) to increase reproductive output, contributed to the rapid recovery of the species within 10 years. Several hybridisation events occurred and although those hybrids were successfully eliminated from the population, concerns remained for the possibility of introgression between the two species that may have gone unnoticed. In this study, we genotyped seven microsatellite loci in both species from the two islands where they coexist, to assess the level of hybridisation and the extent of introgression between the two species. The two species shared no alleles at five of the seven loci genotyped, and cluster analysis, AMOVA and admixture analysis of a total of 174 black robins and 78 Chatham Island tomtits showed no evidence of hybridisation or introgression on either of the two islands where they co-exist. As a result, there is no evidence that black robins are currently in any danger of population decline or extinction through hybridisation with tomtits, although small population size and skewed sex ratio, particularly in the smaller of the two populations, may facilitate future hybridisation events.     

Loss of genetic diversity in an outbreeding species: small population effects in the African wild dog <Emphasis Type="Italic">(Lycaon pictus</Emphasis>)

Genetic studies on the endangered African wild dog (Lycaon pictus) have primarily focused on the few remaining large and viable populations. However, investigations on the many isolated small African wild dog populations might also be informative for species management because the majority of extant populations are small and may contain genetic variability that is important for population persistence and for species conservation. Small populations are at higher risk of extinction from stochastic and deterministic demographic processes than larger populations and this is often of more immediate conservation concern than loss of genetic diversity, particularly for species that exhibit out-breeding behaviour such as long distance dispersal which may maintain gene flow. However, the genetic advantages of out-breeding behaviour may be reduced if dispersal is compromised beyond reserve borders (edge effects), further weakening the integrity of small populations. Mitochondrial DNA and 11 microsatellite genetic markers were used to investigate population genetic structure in a small population of out-breeding African wild dogs in Zambia, which occupies an historical dispersal corridor for the species. Results indicated the Zambian population suffered from low allelic richness, and there was significant evidence of a recent population bottleneck. Concurrent ecological data suggests these results were due to habitat fragmentation and restricted dispersal which compromised natural out-breeding mechanisms. This study recommends conservation priorities and management units for the African wild dog that focus on conserving remaining levels of genetic diversity, which may also be applicable for a range of out-breeding species.     

Monitoring spatiotemporal variation in abundance and dispersal by a pheromone-kairomone system in the threatened saproxylic beetles <Emphasis Type="Italic">Osmoderma eremita</Emphasis> and <Emphasis Type="Italic">Elater ferrugineus</Emphasis>

Pheromone monitoring could provide unique spatial and temporal information about rare and threatened insect species for conservation purposes. Pheromone traps may be especially valuable in detecting fluctuations and declines in vulnerable species, if trap catch can be related to population density. We exploited the pheromone-kairomone system of the hermit beetle Osmoderma eremita and its predator, the red click beetle Elater ferrugineus, to monitor variation in their flight activity during 7 years (2001–2002, 2005–2009). Spatial and temporal flight activity of O. eremita and E. ferrugineus were highly correlated over individual trap replicates and trap days. Yearly flight activities of both species were correlated within two core sites included during all years of the study, and positively affected by temperature both within and between years. Flight activity could not be directly translated to variation in abundance in either species, however. Dispersal rate was likely the main factor explaining flight activity in O. eremita. Normalizing the flight activity of E. ferrugineus against that of O. eremita did not eliminate most of the variability, however, suggesting that flight activity of E. ferrugineus was governed both by dispersal rate and by population density. Higher fluctuations in population density of E. ferrugineus likely render it more vulnerable to local extinction, which may explain the greater rarity of this species. We suggest that preserving large assemblies of suitable hollow trees would be absolutely essential for buffering against stochastic population fluctuations and securing the long-term persistence of E. ferrugineus.     

Evidence for the enemy release hypothesis in <Emphasis Type="Italic">Hypericum perforatum</Emphasis>

The enemy release hypothesis (ERH), which has been the theoretical basis for classic biological control, predicts that the success of invaders in the introduced range is due to their release from co-evolved natural enemies (i.e. herbivores, pathogens and predators) left behind in the native range. We tested this prediction by comparing herbivore pressure on native European and introduced North American populations of Hypericum perforatum (St Johns Wort). We found that introduced populations occur at larger densities, are less damaged by insect herbivory and suffer less mortality than populations in the native range. However, overall population size was not significantly different between ranges. Moreover, on average plants were significantly smaller in the introduced range than in the native range. Our survey supports the contention that plants from the introduced range experience less herbivore damage than plants from the native range. While this may lead to denser populations, it does not result in larger plant size in the introduced versus native range as postulated by the ERH.     

Genetic variability in European black grouse (<Emphasis Type="Italic">Tetrao tetrix</Emphasis>)

We studied microsatellite genetic variation in 14 different geographic populations of black grouse (Tetrao tetrix) across the European range. Populations were grouped in three different fragmentation categories: isolated, contiguous and continuous, respectively. Genetic diversity, measured as observed heterozygosity (H _O), expected heterozygosity (H _E) and allelic richness, were lower in isolated populations as compared to the other two categories that did not differ amongst one another. These results imply that lowered genetic variability in black grouse populations is negatively affected by population isolation. Our results suggest that the connectivity of small and isolated populations in Western Europe should be improved or else these face an increased risk of extinction due to genetic and demographic stochasticity.     

Viability of the Endangered Little Bustard <Emphasis Type="Italic">Tetrax tetrax</Emphasis> Population of Western France

Stochastic computer simulations are used to evaluate the sensitivity of Little bustard population parameters, estimating the survival probabilities of the seven endangered Little bustard populations of central-western France for which conservation actions are currentlybeing or have been implemented. Different scenarios of parameter compensation for those nuclei to establish parameter levels assuring population viability are discussed. Adult survival, productivity per female, initial population size and carrying capacity were the most sensitive parameters in a hypothetical, isolated population. Juvenile survival also affected population survival, although its sensitivity was lower. Sex ratio did not have a linear effect on population survival, but probability of extinction increased for extreme values. Productivity per female and initial population size, varied strongly among the populations studied, determining their average time of extinction and growth rate. When a metapopulation scenario was simulated, the survival probabilities of each population and the metapopulations stayed close to 1.0 if no mortality was associated to migration. When mortality during migration was included in the simulations, the metapopulation's probability of survival significantly decreased under 90%. This approach may help managers to correctly address conservation measures and design effective strategies, which should be directed mainly to improve productivity, enhance female survival, and minimise mortality during migration (e.g. promoting insect-rich nesting substrates, avoiding female killing and nest destruction at harvesting, reducing the risk of collision with powerlines, or controlling poaching).     

Genetic diversity and mating system of the threatened plant <Emphasis Type="Italic">Kirengeshoma palmata</Emphasis> (Saxifragaceae) in Korea

The endangered herb Kirengeshoma palmata, from eastern Asia, has had its population severely reduced in number through habitat loss and fragmentation. All of the individuals within five subgroups at Mt. Baek-un-san, in the southern part of Korea, were genetically surveyed by allozyme analysis. Genetic diversity levels within subgroups were relatively high, and a consistently high outcrossing rate as well as a negligible biparental mating rate were confirmed by this study. Several groups of visibly connected ramets were observed in a clustered distribution which suggested cloning. Absence of mating partner rather than pollinators decreased seed production in small mating groups. The present genetic structure of the five subgroups was probably the result of local extinction of intervening populations. Because K. palmata may be a self-incompatible species, populations with few genets face lowered seed set due to mate scarcity. Thus, this type of population may be at an increased risk of extinction as a result of inbreeding depression, loss of genetic variability, and reduced sexual reproduction. The small, genetically depauperate subgroups may need an input of seeds or plants from other populations in China or Japan in order to regenerate, but the possibility of outcrossing depression leads us to recommend outbreeding among the local subgroups of Mt. Baek-un-san to restore genetic variability.     

Evolutionary history of <Emphasis Type="Italic">Wolbachia</Emphasis> infections in the fire ant <Emphasis Type="Italic">Solenopsis invicta</Emphasis>

Background  

Wolbachia are endosymbiotic bacteria that commonly infect numerous arthropods. Despite their broad taxonomic distribution, the transmission patterns of these bacteria within and among host species are not well understood. We sequenced a portion of the wsp gene from the Wolbachia genome infecting 138 individuals from eleven geographically distributed native populations of the fire ant Solenopsis invicta. We then compared these wsp sequence data to patterns of mitochondrial DNA (mtDNA) variation of both infected and uninfected host individuals to infer the transmission patterns of Wolbachia in S. invicta.     

Genetic variability in the endemic <Emphasis Type="Italic">Leucojum valentinum</Emphasis>

The genetic variability of Leucojum valentinum Pau (Amaryllidaceae), a vulnerable endemic species restricted to a small area in the region of Valencia (Eastern Spain), has been studied using random amplified polymorphic DNA (RAPD) markers. A total of 197 individuals from eleven populations were studied using 13 RAPD primers. Our results show high variability for the species, low differentiation among populations and uncorrelated levels of genetic variability and population size. Four groups in which three populations (SAG, PUG and COL) are separated from all the others were found, but without connection to geographical location.     

Genetic differentiation in sympatric wood ants, <Emphasis Type="Italic">Formica rufa</Emphasis> and <Emphasis Type="Italic">F. polyctena</Emphasis>

Summary Direct observations have suggested that the closely related wood ants Formica polyctena and F. rufa represent different social organizations, with high queen number in F. polyctena and a high frequency of monogynous nests in F. rufa. We examined social organization and genetic population structure in a setup where populations of the two species are sympatric and gene flow between the species is possible. Our aim was to compare social organization in the species, and study evolutionary relationships between them. The observed relatedness among colony workers suggested that the difference in the level of polygyny is quantitative rather than qualitative, with a higher queen number in F. polyctena. The observed difference in polygyny was not accompanied by a difference in spatial genetic differentiation which was weak in both species. The genetic distance between the species is consistent with limited interspecific gene flow. Identification of a few possible F. rufa migrants in F. polyctena populations suggests potential interspecific gene flow. Thus, reproductive isolation of the species may not be complete when they are sympatric.Received 14 March 2003; revised 10 October 2003; accepted 20 October 2003.     

Genetic variation of an endangered Malagasy frog, <Emphasis Type="Italic">Mantella cowani</Emphasis>, and its phylogeographic relationship to the widespread <Emphasis Type="Italic">M. baroni</Emphasis>

We investigated the degree and distribution of the genetic variation, and phylogeography, of two species of Malagasy poison frogs, Mantella cowani and M. baroni. The former is critically endangered due to its restricted distribution, habitat destruction and overcollection for the pet trade. Analysis of 526 bp of mtDNA (cytochrome b) resulted in separate haplotype networks for the two species, and discovered hybridization at a single locality. The two networks confirm the status of M. baroni and M. cowani as separate evolutionary species and units for conservation. Within both mitochondrial haplotype networks, specimens from different localities shared numerous identical haplotypes, even those from the most distant sample sites of M. baroni. Most populations were characterized by high haplotype diversity and no haplotype clades exclusive to geographical regions were observed. Protection of a few large populations of these species is therefore likely to conserve much of the mtDNA genetic diversity found in the entire species. While M. baroni is widespread and occurs in many nature reserves, we recommend efficient legal protection of some M. cowani habitats to protect this species against extinction.     

Distinct electrophoretic polymorphism pattern at alcohol dehydrogenase (<Emphasis Type="Italic">Adh</Emphasis>) locus of <Emphasis Type="Italic">Drosophila melanogaster</Emphasis> natural populations from Turkey

Small number of Drosophila melanogaster populations from two distinct geographical regions of Turkey, Central Anatolia and Black Sea, were studied. Populations sampled were electrophoresed for a single locus, alcohol dehydrogenase (Adh) to assess population differentiation. Both the magnitude of genetic differentiation levels and the population structure based on hierarchical F-statistics allow populations to be grouped on two genetically divergent area, Central Anatolian and Black Sea. One ecological correlate, average yearly maximum rainfall, R _year, seems to track this Adh genetic variation pattern. The study also shows that a typical pattern of geographical Adh polymorphism can emerge with a handfull of populations sampled across a relatively small distance. The text was submitted by the author in English.