49,920 research outputs found
Marie Brockmann-Jerosch and her influence on Alpine phylogeography
At the beginning of the twentieth century, Marie Brockmann-Jerosch wrote, partly in collaboration with her husband Heinrich Brockmann-Jerosch, three influential overview articles on the origin and history of the Swiss alpine flora. Of special interest to her were the types and locations of Pleistocene glacial refugia of alpine plants. She summarised that there had been glacial refugia in the southern and northern peripheral European Alps and also supported glacial survival of high-alpine specialist plants in central Alpine nunatak regions within glaciated areas of the Alps. In contrast, Marie Brockmann-Jerosch dismissed the occurrence of glacial relicts in the lowlands and foothills north of the Alps: she rather saw the conspicuous stations of alpine plants in the lowlands as the result of post-glacial long-distance dispersal of seed out of the Alps. In this article, we first give a brief description of Marie Brockmann-Jerosch's life and then show that modern phylogeographic research has largely proven her views of the glacial history of the alpine flora and that her writings are still intellectually stimulating and worthwhile readin
Native vegetation of the southern forests : south-east highlands, Australian alps, south-west Slopes, and SE Corner bioregions
The Southern Forests study area covers an area of about six million hectares of south-eastern New South Wales, south of Oberon and Kiama and east of Albury and Boorowa (latitude 33° 02’–37 ° 06’ S; longitude 146° 56’ – 147° 06’ E). The total area of existing vegetation mapped was three million hectares (3 120 400 hectares) or about 50% of the study area. Terrestrial, wetland and estuarine vegetation of the Southern Forests region were classified into 206 vegetation groups and mapped at a scale between 1: 25 000 and 1: 100 000. The classification was based on a cluster analysis of detailed field surveys of vascular plants, as well as field knowledge in the absence of field survey data. The primary classification was based on 3740 vegetation samples with full floristics cover abundance data. Additional classifications of full floristics presence-absence and tree canopy data were carried out to guide mapping in areas with few full floristic samples. The mapping of extant vegetation was carried out by tagging vegetation polygons with vegetation codes, guided by expert knowledge, using field survey data classified into vegetation groups, remote sensing, and other environmental spatial data. The mapping of pre-1750 vegetation involved tagging of soils mapping with vegetation codes at 1: 100 000 scale, guided by spatial modelling of vegetation groups using generalised additive statistical models (GAMS), and expert knowledge. Profiles of each of the vegetation groups on the CD-ROM* provide key indicator species, descriptions, statistics and lists of informative plant species.
The 206 vegetation groups cover the full range of natural vegetation, including rainforests, moist eucalypt forests, dry shrub forests, grassy forests, mallee low forests, heathlands, shrublands, grasslands and wetlands. There are 138 groups of Eucalyptus forests or woodlands, 12 rainforest groups, and 46 non-forest groups. Of the 206 groups, 193 were classified and mapped in the study area. Thirteen vegetation groups were not mapped because of their small size and lack of samples, or because they fell outside the study area.
Updated regional extant and pre-1750 vegetation maps of southern New South Wales have been produced in 2005, based on those originally prepared in 2000 for the southern Regional Forest Agreement (RFA). Further validation and remapping of extant vegetation over 10% of the study area has subsequently improved the quality of the vegetation map, and removed some of the errors in the original version. The revised map provides a reasonable representation of native vegetation at a scale between 1: 25 000 and 1: 100 000 across the study area.
In 2005 native vegetation covers 50% of the study area. Environmental pressures on the remaining vegetation include clearing, habitat degradation from weeds and nutrification, severe droughts, changing fire regimes, and urbanisation. Grassy woodlands and forests, temperate grasslands, and coastal and riparian vegetation have been the most reduced in areal extent. Over 90% of the grassy woodlands and temperate grasslands have been lost. Conservation of the remaining vegetation in these formations is problematic because of the small, discontinuous, and degraded nature of the remaining patches of vegetation
Postglacial colonization and parallel evolution of metal tolerance in the polyploid Cerastium alpinum
The Fennoscandian flora is characterized by a high frequency of polyploids, probably because they were more successful than diploid plants in colonizing after the last Ice Age. The first postglacial colonizers were likely poor competitors and became displaced from the lowlands as forests advanced. Consequently, many of these pioneers are currently found only above tree line. However, some have persisted within the forests on open habitats such as naturally toxic serpentine soils where succession is arrested at the pioneer stage. These populations represent relicts of former widely distributed plants. The polyploid Cerastium alpinum L. (Caryophyllaceae) grows on serpentine soils throughout Fennoscandia. C. alpinum populations on different soil types provide a model system for the study of the early postglacial colonization history of Fennoscandia. Genetic markers showed that C. alpinum populations in western Fennoscandia differ genetically from eastern populations, suggesting a two-way colonization. The two lineages meet in a hybrid zone in Northern Scandinavia where a high degree of genetic variation was found. Plants from Fennoscandia and the Western Arctic (Canada, Greenland and Iceland) shared many AFLP fragments, which suggests they originate from common refugia. The Fennoscandian populations were more distantly related to the populations in potential refugia in southern Europe. In fact, the northern populations contained AFLP fragments not found in populations in the Pyrenees and the Alps. Lack of chloroplast DNA variation indicates fast postglacial range expansions and/or a recent origin of C. alpinum. Crosses were made to establish the inheritance of enzyme markers. The results strengthen the evidence for an allopolyploid origin of C. alpinum. Adjacent serpentine and non-serpentine populations of C. alpinum provide a model system of natural replicates to test whether adaptation to serpentine is constitutive (common for all populations) or locally evolved. A growth experiment with high concentrations of nickel and magnesium, two metals that limit the fertility of serpentine soils, showed that the degree of metal tolerance reflects site-specific soil conditions. Since local adaptation was found in both the eastern and the western immigration lineages, the postglacial colonization of Fennoscandia has involved parallel evolution of metal tolerance in C. alpinum
Increasing the resilience of the Australian alpine flora to climate change
The alpine region around Australia’s highest mountain, Mt Kosciuszko, is part of one of the three most at risk ecosystems in Australia from climate change. With higher temperatures and decreased precipitation, snow cover is already declining with even greater reductions predicted in the short to medium term (2020 to 2050). Consequently the distribution of many native plants and animals may contract, while the distribution of weeds and feral animals may expand. Wildfires in the region are also likely to be more frequent and intense. To contribute to our understanding of how changes in the environment alter plant composition and ecological process, we conducted a series of functional trait analyses of existing composition datasets. We collected trait data in the field for 220 species including canopy height, leaf area, leaf dry matter content and specific leaf area (SLA). Variation in traits among the alpine flora was not related to species distributional ranges. Traits were strongly associated with growth forms, with shrubs often taller than herbs and graminoids, but often had small, tough, long-lasting leaves. Species traits were combined with relative cover values to calculate community trait weighted means, a commonly used measure of functional diversity. Functional diversity varied with altitude/duration of snow cover. For example, shrubs which are taller with small tough leaves dominated lower altitude summits, while at higher altitude summits, large, soft leaved herbs and graminoids dominated. Late lying snowpatches areas with short growing seasons were dominated by low growing herbs and graminoids with small leaves while areas with longer growing seasons were dominated by herbs and graminoids that were taller and had larger leaves. Recovery from fire differed among plant communities. The composition and functional diversity of recovering tall alpine herbfield is trending towards that of equivalent unburnt sites, while burnt windswept feldmark was colonised by graminoids and herbs that are often found in tall alpine herbfield species, with limited shrub recovery in the first nine years post fire. Grazing by feral hares had no effect on composition or functional diversity, while vegetation recovering from cattle grazing showed clear changes in composition and functional diversity even 43 years later. Prioritising management for this high value conservation region, therefore, involves enhancing resilience by minimising existing threats, particularly those from fire, weeds and hard-hooved grazing animals which will be exacerbate by climate change.Please cite as: Pickering, C, & Venn, S, 2013 Increasing the resilience of the Australian flora to climate change and associated threats: a plant functional traits approach National Climate Change Adaptation Research Facility, Gold Coast, pp. 94 Abstract The alpine region around Australia’s highest mountain, Mt Kosciuszko, is part of one of the three most at risk ecosystems in Australia from climate change. With higher temperatures and decreased precipitation, snow cover is already declining with even greater reductions predicted in the short to medium term (2020 to 2050). Consequently the distribution of many native plants and animals may contract, while the distribution of weeds and feral animals may expand. Wildfires in the region are also likely to be more frequent and intense. To contribute to our understanding of how changes in the environment alter plant composition and ecological process, we conducted a series of functional trait analyses of existing composition datasets. We collected trait data in the field for 220 species including canopy height, leaf area, leaf dry matter content and specific leaf area (SLA). Variation in traits among the alpine flora was not related to species distributional ranges. Traits were strongly associated with growth forms, with shrubs often taller than herbs and graminoids, but often had small, tough, long-lasting leaves. Species traits were combined with relative cover values to calculate community trait weighted means, a commonly used measure of functional diversity. Functional diversity varied with altitude/duration of snow cover. For example, shrubs which are taller with small tough leaves dominated lower altitude summits, while at higher altitude summits, large, soft leaved herbs and graminoids dominated. Late lying snowpatches areas with short growing seasons were dominated by low growing herbs and graminoids with small leaves while areas with longer growing seasons were dominated by herbs and graminoids that were taller and had larger leaves. Recovery from fire differed among plant communities. The composition and functional diversity of recovering tall alpine herbfield is trending towards that of equivalent unburnt sites, while burnt windswept feldmark was colonised by graminoids and herbs that are often found in tall alpine herbfield species, with limited shrub recovery in the first nine years post fire. Grazing by feral hares had no effect on composition or functional diversity, while vegetation recovering from cattle grazing showed clear changes in composition and functional diversity even 43 years later. Prioritising management for this high value conservation region, therefore, involves enhancing resilience by minimising existing threats, particularly those from fire, weeds and hard-hooved grazing animals which will be exacerbate by climate change
Does residence time affect responses of alien species richness to environmental and spatial processes?
One of the most robust emerging generalisations in invasion biology is that the probability of invasion increases with the time since introduction (residence time). We analysed the spatial distribution of alien vascular plant species in a region of north-eastern Italy to understand the influence of residence time on patterns of alien species richness. Neophytes were grouped according to three periods of arrival in the study region (1500–1800, 1800–1900, and > 1900). We applied multiple regression (spatial and nonspatial) with hierarchical partitioning to determine the influence of climate and human pressure on species richness within the groups. We also applied variation partitioning to evaluate the relative importance of environmental and spatial processes. Temperature mainly influenced groups with species having a longer residence time, while human pressure influenced the more recently introduced species, although its influence remained significant in all groups. Partial regression analyses showed that most of the variation explained by the models is attributable to spatially structured environmental variation, while environment and space had small independent effects. However, effects independent of environment decreased, and spatially independent effects increased, from older to the more recent neophytes. Our data illustrate that the distribution of alien species richness for species that arrived recently is related to propagule pressure, availability of novel niches created by human activity, and neutral-based (dispersal limitation) processes, while climate filtering plays a key role in the distribution of species that arrived earlier. This study highlights the importance of residence time, spatial structure, and environmental conditions in the patterns of alien species richness and for a better understanding of its geographical variation
Distribution and diversity of exotic plant species in montane to alpine areas of Kosciuszko National Park
Diversity and distribution of exotic plant taxa in Kosciuszko National Park in south-eastern Australia were reviewed based on 1103 records of exotics from 18 vegetation surveys conducted between 1986 and 2004. 154 taxa from 23 families were recorded in the alpine to montane zones, with eleven taxa in the alpine, 128 taxa in the subalpine and 69 taxa in the montane zone. Nearly all taxa were associated with anthropogenic disturbance with only four taxa exclusively recorded in natural areas. 62 taxa were recorded from subalpine ski resort gardens, and although not recorded as naturalised in the vegetation surveys, their presence in the Park is a concern.
Road verges provided habitat for numerous exotics (65 taxa). 44 taxa were recorded in both disturbed and natural locations but most were uncommon (33 taxa < 2% frequency). Nine common taxa Acetosella vulgaris, Achillea millefolium, Agrostis capillaris, Anthoxanthum odoratum, Cerastium spp., Dactylis glomerata, Hypochaeris radicata, Taraxacum officinale and Trifolium repens comprised 68% of records. These species are common to disturbed areas in other areas of Kosciuszko National Park, NSW and worldwide. The forb Acetosella vulgaris was the most ubiquitous species particularly in natural areas where it was recorded at 36% frequency. Based on the data presented here and a recent review of other data sets, there are at least 231 exotic taxa in the Park (including exotics in gardens). The increasing diversity and abundance of exotics is a threat to the natural values of this Park
Syntaxonomic conspectus of the vegetation of Catalonia and Andorra. I: Hygrophilous herbaceous communities.
The first part of a general survey of the vegetation of Catalonia and
Andorra, this paper reports all the phytocoenological associations and subassociations recorded in this area. For each community, we provide the correct name and usual synonyms, its typification (where appropriate), all the references including relevés, and the most outstanding features of its structure, species composition, ecology, distribution and diversity. Moreover, associations and subassociations are ordered appropriately in a syntaxonomic scheme. Syntaxonomic ranks are considered in a fairly broad, conservative sense. This classification established 101 associations, which correspond to the classes Lemnetea, Zosteretea, Potametea, Littorelletea, Montio-Cardaminetea, Phragmiti-Magnocaricetea, Scheuchzerio-Caricetea, Isoeto-Nanojuncetea and Molinio-Arrhenatheretea
Nomenclature adjustments and new syntaxa of the arctic, alpine and oro-Mediterranean vegetation
Proposte sintassonomiche e nomenclaturali per la vegetazione della Tundra alpina. Il capitolo riguardante l'alta quota appenninica è il più corposo e propone il nuovo syntaxon Leontopodio-Elynion a livello di alleanza. La grande novità sta nel fatto che questa alleanza è da considerarsi anfi-Adriatica e unsice Appennino e balcani, differenziandosi dall'alleanza già definita da altri per le Alpi. i Pirenei e i Carpazi.During preparation of the European checklist of vegetation units (EuroVegChecklist), it became clear that some earlier described syntaxa need to be typified in order to stabilize nomenclature and some new syntaxa need to be described. Here we propose nomenclature adjustments and formal description of four new alliances
for the Arctic, alpine and oro-Mediterranean vegetation of Europe, Greenland and Anatolia. First, we typify the class Juncetea trifidi. Second, we describe four new alliances, such as the Puccinellion nuttallianae (Low-Arctic salt steppes of Greenland; class Saxifrago tricuspidatae-Calamagrostietea purpurascentis), Dryado octopetalae-
Caricion arctisibiricae (Arctic tundra vegetation of north-eastern European Russia; class Carici rupestris-Kobresietea bellardii), Leontopodio nivalis-Elynion myosuroidis (southern European alpine tundra vegetation; class Carici rupestris-Kobresietea bellardii) and Lagotido uralensis-Caricion ensifoliae (alpine tundra vegetation of the Southern Ural Mountains; class Juncetea trifidi). Two new associations are described within the first two of these alliances. Finally, we present an interpretation of the alliance Muscario-Scillion nivalis
Floristics of the South American Páramo moss flora
The South American paramos appeared in Pliocene times and persist to the present day. The moss flora of this habitat consists of an estimated 400 species that comprise 8 floristic groups. In Venezuela these groups and their percent representation are as follows: neotropical 37%, Andean 26%, cosmopolitan 18%, Andean-African 8%, neotropical-Asiatic 3%, neotropical-Australasian 2%, temperate Southern Hemisphere 2% and northern boreal-temperate 2%. Acrocarpous taxa outnumber pleurocarps by nearly 3:1. The neotropical and Andean floristic stocks likely were present prior to late Pliocene orogenies that elevated the cordillera above climatic timberlines. These species may have existed in open, marshy areas (paramillos) or may have evolved from cloud forest ancestors. Taxa of northern boreal- temperate affinities, including those with Asiatic distributions, probably arrived in the paramos during the Pleistocene, a period which may also have seen the establishment in the Northern Andes of some cosmopolitan elements. Species with temperate Southern Hemisphere and Australasian affinities likely spread first to austral South America thence migrated northward during a cool, moist interval sometime over the past 2.5-3 million years or may have become established in the paramos as a result of long- distance dispersal
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