The non-native vascular flora of the Falkland Islands

Summary

Non-native species form a significant, but under-recorded, component of the Falkland Islands vascular flora. With this in mind a comprehensive re vie w of the non-native flora of the Falkland Islands was undertaken for the first time since the publication of the definitive Flora in 1968. We have recorded 175 non-native taxa, from 46 families, from the Falkland Islands which are listed with accompanying notes on habitat, status and distribution. Twenty-nine of these are likely to be commonly encountered, though only Aira praecox, Cerastium fontanum, Rumex acetosella and Sagina procumbens are near ubiquitous throughout. The origins of much of the non-native flora are obscure, however most species seem to be of European descent, and a significant proportion of taxa seem to have become established after introductions for agricultural and horticultural purposes.     

Age and implications of the Forest Bed, Falkland Islands, southwest Atlantic Ocean: Evidence from fossil pollen and spores

Diverse pollen and spore assemblages (microfloras) are preserved in organic clays and lignites associated with fossil tree remains in the Forest Bed. At present, these microfloras provide the only reliable basis for determining the age, composition, structure and affinity of the Forest Bed community. The Bed is suggested to be Middle? Miocene to Early Pliocene (age range Oligocene–Early Pliocene) based on the time distribution of a number of rare pollen types and the present-day ecology of their nearest living relatives in central–southern America and the southwest Pacific. The wet forest community whose remains form the Forest Bed was a form of broadleaf-gymnosperm temperate rainforest in which Dacrydium, Lagarostrobos and Podocarpus are likely to have formed an overstorey above a closed canopy dominated by Nothofagus (Nothofagus) spp. The latter subgenus is now endemic to ±uniformly wet regions in southern South America whilst two of the tall gymnosperms (Dacrydium, Lagarostrobos) are now endemic to the southwest Pacific region. An extinct, probable shrub-sized, conifer (Podosporites microsaccatus) appears to have formed the ground cover. Ferns and fern allies were very rare, in contrast to most living Nothofagus-gymnosperm communities. Fossil pollen and spore types produced by uncommon subcanopy tree, shrub and fern species potentially provide a means for more accurately dating the deposit once their time of first occurrence and extinction at subantarctic latitudes in the southwest Atlantic region is established (nearest living equivalents given in parentheses) — Clavatipollenites cf glarius (Hedyosmum), Thymelaepollis sp. (Ovidia-type) and Cyatheacidites annulatus (Lophosoria). This will require palynostratigraphic analysis of Late Palaeogene–Neogene sediments recovered from basins surrounding the Falkland Islands, for example from DSDP Site 329 drilled on the Maurice Ewing Bank at the eastern margin of the Falkland Plateau.     

Behaviour, natural history, and annual cycle of the Henderson Island rail Porzana atra (Aves: Rallidae)

The little known endemic Henderson Island rail (or Henderson rail) Porzflna atra , inhabits forest on the coastal plain and upraised plateau of Henderson Island. Rails were studied for 15 months from January 1991 to March 1992. The population was estimated at c. 6200 individuals living in pairs or cooperative groups of 3–4 adults on territories averaging about 1 ha. Two or three eggs were laid in covered or open nests near the ground from mid-July to mid-February. Up to five consecutive nesting attempts were made in cases where eggs or young chicks were lost. Adults laid a second clutch when chicks were fully feathered at about one month of age. Both sexes incubated and helped rear the young. Older chicks sometimes helped feed younger siblings. Dispersal of juveniles from the natal territory took place in April. Adult birds underwent a rapid, simultaneous post-nuptial moult of the remiges in February-April; the post-juvenile moult involved body feathers only. Data on morphometries, breeding ecology, courtship behaviour and voice are compared with available information for the spotless crake P. tabuensis , the Henderson rail's closest relative and probable ancestor. These comparisons provide some information on how these two taxa have differentiated since rails arrived on Henderson Island some time in the last 380000 years.     

Origin and evolution of the endemic Canary Island shrews (Mammalia: Soricidae)

Until recently the North Atlantic Islands were believed to house only mammals introduced by humans. Recent work has demonstrated that at least the Canary Islands house(d) a native mammal fauna. New data including chromosome numbers, genetic distances and analysis of vocalizations are given for the two extant shrew species, Crocidura canariensis and C. osorio , and their possible sister taxa are evaluated. Evidence is presented for the hypothesis that the two island species originated from two different lineages of the Palaearctic branch of the genus Crocidura. The data support the present status of the Canary Island shrews as local endemics of high conservation priority.     

Towards eradication: The history and management of Bitou Bush on K'gari‐Fraser Island,Australia

Persistence and dedication over the long term has been a key to success in control of this Weed of National Significance on World Heritage Listed K'gari‐Fraser Island in Queensland, Australia. Systematic surveys and treatment show that the goal of Bitou Bush eradication is worthwhile and can inspire other such projects within the region and beyond.     

Thirty years of vegetation dynamics in response to a fluctuating rabbit population on sub‐Antarctic Macquarie Island

Australia's sub‐Antarctic Macquarie Island is presently undergoing one of the most ambitious vertebrate pest eradication programmes ever undertaken. The anticipated success of this programme will release the island's tundra‐like vegetation from well over a century of grazing and disturbance from House Mouse (Mus musculus), Ship Rat (Rattus rattus) and most significantly European Rabbit (Oryctolagus cuniculus). This study describes results from 30 years of vegetation quadrat monitoring (prior to the most recent and comprehensive pest eradication programme) when lower level pest animal control programmes were underway. Plant species were assigned to one of five distinct functional plant groups: Indigenous short‐lived perennials, Introduced short‐lived perennials, Indigenous perennials rarely grazed by rabbits, Indigenous perennials occasionally grazed by rabbits and Indigenous long‐lived perennials heavily grazed by rabbits, with one species, Agrostis magellanica, analysed as a sixth monospecific group. Results from monthly rabbit counts were used to compare changes in abundance of these six groups under different rabbit populations. It was found that there were three distinct phases of rabbit activity during the study period, indicated by (i) an initial very high count year in 1980–1981, followed by (ii) 20 years of low counts ending in 2001–2002 after which (iii) counts rose to medium/high until the commencement of the eradication programme in 2010–2011. Vegetation composition and progression were distinct for these three rabbit count phases. The first four of the plant functional groups decreased under lower count periods and increased in cover under higher rabbit count periods. Agrostis magellanica appears to respond primarily to interspecies competition and is disadvantaged under extended periods of low rabbit numbers. Indigenous long‐lived perennials heavily grazed by rabbits, which includes the large tussocks and megaherbs, is inversely related to rabbit numbers. During the study period, there has also been an overall decline in plant species richness with average species count per quadrat falling by between 0.6 and 2.7 taxa. This study attempts to address the observed vegetation change from this long‐term monitoring, to discuss other potential contributing factors and to use the results to predict likely future vegetation changes after eradication of vertebrate pests.     

Ecology and conservation status of endemic freshwater crabs in Lake Tanganyika, Africa

Sedimentation resulting from riparian deforestation has a wide range of detrimental effects on aquatic biodiversity, but predicting the full consequences of such disturbances requires an understanding of the ecosystem’s key functional components. We investigated the ecology and response to sedimentation of the diverse, endemic freshwater crabs of Lake Tanganyika, which may occupy important positions in littoral foodwebs. Our surveys revealed crab distribution patterns to be patchy, and that crabs can be locally abundant (0–28 individuals m⁻²). Crab densities decreased with depth and the dry mass of crab assemblages ranged from 0.0 to 117.7 g m⁻². Comparisons among sites revealed significant effects of sedimentation on crab assemblage evenness, but provided no evidence that sedimentation has altered densities, incidence or species richness. The resilience of crabs to sedimentation might be related to their intraspecific dietary breadth. Stable isotope data (δ¹³C and δ¹⁵N) from crabs and their potential food resources indicated differences in trophic roles among endemic crab species. Overall, crabs occupy higher trophic positions than most other invertebrates, and they draw upon both benthic and planktonic energy pathways. The high biomass and top-predator status of some crab species suggests the potential for cascading effects on organisms lower in the food web.     

Development of community metrics to evaluate recovery of Minnesota wetlands

Monitoring wetland recovery requires assessment tools that efficiently and reliably discern ecosystem changes in response to changes in land use. The biological indicator approach pioneered for rivers and streams that uses changes in species assemblages to interpret degradation levels may be a promising monitoring approach for wetlands. We explored how well metrics based on species assemblages related to land use patterns for eight kinds of wetlands in Minnesota. We evaluated land use on site and within 500 m,1000 m, 2500 m and 5000 m of riverine, littoral, and depressional wetlands (n = 116) in three ecoregions. Proportion of agriculture, urban, grassland, forest,and water were correlated with metrics developed from plant, bird, fish, invertebrate, and amphibian community data collected from field surveys. We found79 metrics that relate to land use, including five that may be useful for many wetlands: proportion of wetland birds, wetland bird richness, proportion of insectivorous birds, importance of Carex, importance of invasive perennials. Since very few metrics were significant for even one-half of the wetland types surveyed, our data suggest that monitoring recovery in wetlands with community indicators will likely require different metrics,depending on type and ecoregion. In addition, wetlands within extensively degraded ecoregions may be most problematic for indicator development because biotic degradation is historic and severe. This revised version was published online in July 2006 with corrections to the Cover Date.     

The death of birds on the sea coast of northeastern Sakhalin Island

The taxonomical composition of dead birds found on the northeastern coast of Sakhalin Island and the causes of their death were studied. Sites with high, average, and low concentration of dead birds were identified. The period of highest mortality of birds (July–August) coincided with the beginning of massive migrations of birds and large numbers of young birds after termination of the nesting season. Collection of bird remains in periods of bird migrations and breeding, in addition to other methods of ornithological research (visual observations, fowling, shooting), can provide useful information on the avifauna and ecological state of the investigated region.     

The diet of the Weddell seal <Emphasis Type="Italic">Leptonychotes weddellii</Emphasis> at Laurie Island,South Orkney Islands

The diet of the Weddell seal Leptonychotes weddellii at the South Orkney Islands was investigated by the analysis of 44 and 26 faecal samples collected from the beaches of Laurie Island from May 1999 to January 2000 and from October to December 2001, respectively. The diet was diverse and both pelagic and benthic-demersal organisms were represented in the samples. Fish were the most frequent prey of the samples in both seasons, and fish and krill were the most numerous prey items. Octopods predominated by mass in 1999, whereas krill constituted the bulk of the diet in 2001, a fact that was not observed previously. Among fish, Gobionotothen gibberifrons was largely the species that contributed mostly to the diet, whereas pelagic fish could not be identified in the samples. The results are compared with information from other study areas and discussed in relation to the consumption of krill.     

The flora of Prespa National Park with emphasis on species of conservation interest

The flora of Prespa National Park is composed of 1326plant species. Among them are 17 Pteridophytes and1309 Spermatophytes, represented by 11 Gymnosperms,1057 Dicotyledons and 241 Monocotyledons. The flora isevaluated and categorised into species which can beconsidered as new for the Greek flora, species underinternational protection, and rare local speciesthreatened with extinction. Plant species are alsocategorised according to their ecologicalrequirements, with special reference to the endemicspecies and their centres of origin in respect totheir total percentage (15.4%).     

The last population of the Woodland Brown butterfly (<Emphasis Type=Italic>Lopinga achine</Emphasis>) in the Czech Republic: habitat use,demography and site management

The distribution of Lopinga achine (Lepidoptera Nymphalidae, Satyrinae) in the Czech Republic has declined from thirty grid squares before 1950 to just one extant population, restricted to a single area of deciduous woodland. A review of historical sites shows that this species used to occur in various types of deciduous woodland with a relatively sparse canopy maintained by coppicing and/or grazing. The extant population inhabits mature woodland with a mean canopy cover of 60% (quartiles 50% and 65%), sparse shrubs and a species-rich herb layer containing plant species requiring dry, warm and nutrient-poor conditions. The larval host plants are the fine-leafed sedges, Carex fritschii and C. michelii. In 2006, the total population contained about 10,000 adults but this may be an over-estimate, biased by male behaviour. Measurements of adult mobility, well approximated by an inverse-power function, suggested that all existing colonies are interconnected by dispersal. Continuing existence of the population depends on two conditions; nutrient-poor conditions for a diverse ground flora and a sparse tree canopy. While canopy closure is gradually increasing, the herb layer is threatened by soil enrichment due to the demise of traditional grazing, litter raking and grass mowing in woodlands. Any future management to favour Lopinga achine should include both measures to maintain a sparse canopy and measures to export biomass, such as raking or mowing of ground flora or, preferably, re-establishment of grazing. An erratum to this article can be found at     

Allozyme diversity in natural populations of Viola palmensis Webb & Berth. (Violaceae) from La Palma (Canary Islands): implications for conservation genetics

Genetic diversity was measured by allozyme electrophoresis in eight natural populations of the threatened Canarian endemic Viola palmensis Webb & Berth. (Violaceae). Nineteen alleles corresponding to 11 gene loci were detected. High levels of genetic diversity were found, ranging from 36.3 to 45.4 % for the percentage of polymorphic loci (P), from 1.45 to 1.60 for the average number of alleles per locus (A) and from 0.128 to 0.200 for the expected heterozygosity (H(e)). Between 85.5 and 96.6 % of genetic variability was apportioned within populations. As a whole, populations were not at Hardy-Weinberg equilibrium, with a deficit of heterozygous individuals attributable to the existence of genetic structuring in the populations analysed. The levels of interpopulation genetic differentiation were low (mean F(ST) = 0.100), while genetic identity pair-wise comparisons were high (mean I = 0.973) suggesting considerable levels of gene flow among populations. No relationship was detected between genetic differentiation and geographical distances between populations. An outcrossing insect-mediated breeding system might contribute to pollen dispersion of this species. For conservation genetics we suggest in situ preservation areas are defined that are free of disturbance and that include populations with the highest genetic diversity.     

The potential role of large herbivores in nature conservation and extensive land use in Europe

The concept of ecosystem restoration is gaining momentum in western Europe. This is necessary because in most managed nature reserves one or more of the following processes, which are analogous to those that have led to the dramatic loss of biological diversity in Europe, are still operating: continuing nutrient output, continuing high level of disturbance and fixing the system in some successional stage. This is partly because most management activities have been derived from, or copy, former agricultural practices. The study of natural ecosystems has revealed the key role large herbivores have in maintaining structural diversity in the vegetation and so biological diversity. Because of this they have been used as tools in achieving a variety of conservation goals. Here, various effects large herbivores can have on plant species composition, structural diversity of the vegetation and fauna are briefly reviewed. Attention is given to pasture-woodlands in southern Europe, which often have a relatively high biological diversity and share some key features with natural ecosystems: very low nutrient input, extensive grazing with large herbivores and the presence of natural tree cover. In a number of European countries attempts are being made to restore normal functioning multi-(herbivore) species ecosystems.     

The natural history of an HLA haplotype and its recombinants

 The presence of haplotype-specific recombination sites can be determined by analyzing the conservation of extended haplotypes in the population. This approach considers all meioses in the history of the population and requires the presence of characteristic markers that easily allow the identification of the haplotype or of its recombined segments. The recombination breakpoint can then be mapped by looking for shared alleles between haplotypes selected through the specific marker/s. We identified a rare perfect tandem duplication of a 145 base pair segment in the LTA promoter, which tags a B60 (B60D) haplotype. The duplication was detected in 16/90 B60 ⁺ Europeans, while absent in 101 B60 ⁺ Orientals. The conservation of the class I end and the extreme variability of the class II end suggested that the present-day B60D haplotypes originated from an ancestral haplotype by recombination events centromeric to the duplicated sequence. Through a fine mapping using markers of the HLA central region a preferential recombination site was localized in the 60 kilobase interval between TNFd,e, and D6S273/K11 Amicrosatellite loci (i.e., between LST1 and BAT3 genes). This site behaves as a potent recombination enhancer leading to fragmentation in most of the extant B60D haplotypes and can be considered responsible for their “instability”. In the relatively recently founded Finnish population, where the LST1/BAT3 interval recombination has probably not yet had the chance to occur, a founder effect can explain the presence of a rare DP (DPB1 ^* 1601) allele in most B60D haplotypes in this population. Received: 15 October 1997 / Revised: 23 December 1997     

The natural history of the ethical concept and its implications for the present natural equilibrium

The present article was originally published in the medical italian journal,Rassegna Medica, 1984. The author, on the basis of the recent development of the biotechnology, genetic engineering and environment exploitation by man, attempts to reconstruct the natural history of the ethical concept and its implications for the present natural equilibrium. On this basis he suggests a concept of bioethics which stresses Man-Environment interaction.