Search results for "Richness"

Size matters in studies of dead wood and wood-inhabiting fungi

2011

Abstract Because biased biodiversity surveys may result in ineffective use of conservation or research resources it is important that measures for biodiversity are accurate. In forest ecosystems wood-inhabiting fungi are an ecologically important species group. We addressed the question whether or not the traditional methodology to survey only coarse woody debris provides accurate estimates of the assemblages of wood-inhabiting fungi or the dead wood itself. In this study, we included all dead wood pieces irrespective of the diameter. Our results showed that the chosen minimum size of studied dead wood pieces has crucial importance for species recordings of wood-inhabiting fungi and for rec…

Quantifying the Indicator Power of an Indicator Species

2009

Biodiversity indicator species are needed for classifying biotopes and sites for conservation, and a number of methods have been developed for determining indicator species for this purpose. Nevertheless, in addition to site classification, there is sometimes a need to define an indicator species that indicates the occurrence of another species. For example, when a species of interest (target species) is difficult to detect or identify, a reliable indicator species can function as a tool that saves time and money. We derived a method that provides a quantitative measure of the indicator power (IP) of an indicator species for the target species or any species assemblage. We calculated the me…

Effects of Local Disturbance of Tropical Forests on Frugivores and Seed Removal of a Small-Seeded Afrotropical Tree

2008

Small-scale, local disturbance of tropical forests, for example from selective logging, is widespread, but its effects on biodiversity and ecosystem function have rarely been studied. In 3 East African tropical rainforests, we investigated the effect of different levels of local forest disturbance on the frugivore community and on tree visitation and fruit removal rates of the small-seeded tree Celtis durandii. We quantified birds and primates in little and heavily disturbed sites, distinguishing between forest specialists, forest generalists, and forest visitors. We quantified frugivorous tree visitors and seed removal rates of C. durandii trees in the same sites. Forest disturbance reduce…

2015

Prey preference of top predators and energy flow across habitat boundaries are of fundamental importance for structure and function of aquatic and terrestrial ecosystems, as they may have strong effects on production, species diversity, and food-web stability. In lakes, littoral and pelagic food-web compartments are typically coupled and controlled by generalist fish top predators. However, the extent and determinants of such coupling remains a topical area of ecological research and is largely unknown in oligotrophic high-latitude lakes. We analyzed food-web structure and resource use by a generalist top predator, the Arctic charr Salvelinus alpinus (L.), in 17 oligotrophic subarctic lakes…

How livestock grazing affects vegetation structures and small mammal distribution in the semi-arid Karoo

2000

In this study we investigated vegetation changes superimposed by grazing and their effect on small mammals in the Karoo (South Africa) on grazed farmland and an adjacent, 10-year livestock enclosure. Plains and drainage line habitats were compared by monitoring vegetation height and cover, and small mammal species composition and abundance along transects. Animals were captured by live trapping. Vegetation cover was low on the grazed compared to the ungrazed study site, but vegetation height did not differ. The number of small mammal individuals and the number of species captured was higher at the ungrazed study site. Two species of climbing rodents captured in the ungrazed drainage line we…

Mapping floristic diversity: a case study in Sicily

2021

This paper presents an operational methodology to map and analyze the floristic richness of “target species” in Natura 2000 sites, making use of G.I.S. tools and procedures. A Floristic diversity map (scale 1:50,000), covering an area of 612 km2, was produced by a team of experts as part of the management plans of “Madonie Mountains” Sites of Community Importance (SCIs), located in Sicily (Italy). The primary grid map represents the richness of “target species”, which include species of Community interests, taxa on the National Red List, endemic and threatened, species protected under International Conventions, taxa of phytogeographic importance. Secondary data frames include a three-dimens…

Nested assemblages resulting from host size variation: the case of endoparasite communities in fish hosts

2001

Nested species subsets are a common pattern in many types of communities found in insular or fragmented habitats. Nestedness occurs in some communities of ectoparasites of fish, as does the exact opposite departure from random assembly, anti-nestedness. Here, we looked for nested and anti-nested patterns in the species composition of communities of internal parasites of 23 fish populations from two localities in Finland. We also compared various community parameters of nested and anti-nested assemblages of parasites, and determined whether nestedness may result simply from a size-related accumulation of parasite species by feeding fish hosts. Nested parasite communities were characterised b…

Long-Term Effects of Climate Warming on Forest Soil Collembola

2005

Long-term changes in the collembolan community structure were studied in a Scots pine forest in northern Latvia over a period of 11 successive years (1992–2002). Soil Collembola were yearly sampled from three pine forest stands of different age – young (30 to 40 years old), middle-aged (50 to 70 years old) and old (150 to 200 years old). During the study period a statistically significant increase in sums of positive temperatures (>+4°C) was recorded and a gradual decrease in species richness of Collembola was observed in all forest stands. The study showed that sums of positive air temperatures produce statistically significant effects on collembolan populations. Community responses were s…

Role of the Siberian flying squirrel as an umbrella species for biodiversity in northern boreal forests

2008

Abstract One of the potentially useful indirect shortcut methods in biodiversity conservation is the umbrella species concept. An umbrella species can be seen relatively demanding for the size of the area and probably also for certain habitat types: conservation management for the umbrella species would thus encompass other species preferring similar habitats but with smaller area requirements. As such, it has a comprehensive spatial aspect for landscape planning. We tested the role of the Siberian flying squirrel ( Pteromys volans ) as an umbrella species for wood dependent species among red-listed and old-growth forest associated polypores, epiphytic lichens and beetles. Flying squirrels …

Diversity of meiofauna in the lacustrine profundal zone: Bathymetric differences and influence of environmental factors

1993

The diversity and species richness of total meiofauna, Harpacticoida and Oligochaeta in relation to depth and other environmental variables were studied at nine stations and in two profundal depth zones in Lake Paijanne which includes both oligotrophic and eutrophicated or organically loaded areas.