Search results for "rare species"
showing 10 items of 49 documents
Fuzzy Quantification of Common and Rare Species in Ecological Communities (FuzzyQ)
2020
Abstract1. Most species in ecological communities are rare whereas only a few are common. This distributional paradox has intrigued ecologists for decades but the interpretation of species abundance distributions remains elusive.2. We present Fuzzy Quantification of Common and Rare Species in Ecological Communities (FuzzyQ) as an R package. FuzzyQ shifts the focus from the prevailing species-categorization approach to develop a quantitative framework that seeks to place each species along a rare-commonness gradient. Given a community surveyed over a number of sites, quadrats, or any other convenient sampling unit, FuzzyQ uses a fuzzy clustering algorithm that estimates a probability for eac…
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…
Emulating natural disturbances in boreal Norway spruce forests: Effects on ground beetles (Coleoptera, Carabidae)
2014
The disturbance regime of boreal forests has been substantially altered by human influence in northern Europe. In this context, emulations of natural disturbance have become increasingly common as management tools to minimize negative effects of forestry on biodiversity. In a large-scale habitat-restoration experiment conducted in Norway spruce stands in southern Finland, we tested the effects of controlled burning, partial harvesting, and increasing the amount of downed wood on ground beetles (carabids). We also evaluated the effects of moisture gradients within harvested sites. We collected beetles seven years after the treatments. The moisture gradient was the strongest determinant of ca…
A comparison of two methods for surveying aquatic macrophyte communities in boreal lakes: Implications for bioassessment
2013
To compare the performance of two common methods for surveying boreal lake aquatic macrophyte communities (the transect survey and the phytolittoral inventory) in lake bioassessment, we studied five small humic lakes with both methods. In addition to this pairwise comparison, we contrasted available independent sets of reference lake data of either methodological origin. Specifically, we compared the observed species richness and a number of ecological quality (community) metrics and their variability both between the methods and within them in relation to sampling effort and operator. With the phytolittoral inventory, more taxa (mean 38.8 ± s.d. 12.1) were observed than with transect surve…
A report on the conservation status of segetal weeds in Tajikistan
2014
Summary Intensification of agriculture has significantly diminished the populations of segetal weeds worldwide in recent decades. Remarkable changes to the entire flora and vegetation of man-made habitats are being observed in agroecosystems. The present study analyses, for the first time, the threat status of segetal weeds in Tajikistan. A group of 871 weed species were evaluated against IUCN criteria. The assessment of threat status revealed that 214 weed taxa have to be regarded as threatened in Tajikistan, including 18 endemic and four subendemic plants. Five species have been classified as extinct, 27 as critically endangered, 27 as endangered, 39 as vulnerable, 34 as near threatened a…
Additions to the vascular flora of central Italy. Second contribution
2018
In this paper, new floristic records for 55 taxa for central Italy are reported. In particular, 39 taxa are native and 16 aliens, 9 are new or confirmed to Abruzzo, 1 to Marche, 21 to Molise, 16 to Umbria, 1 is excluded from the flora of Abruzzo, 1 from Molise and 1 from Lazio. Furthermore, new distribution data for 2 rare species in Abruzzo and Molise are reported.
The role of rock mining for maintaining Dauco carotae-Crepidetum rhoeadifoliae Hejný et Grüll in Hejný et al. 1979 — a new to Poland plant association
2013
AbstractThis work presents the Dauco carotae-Crepidetum rhoeadifoliae plant association, which is new to Poland. The association has been observed in industrial reclamation areas in the vicinity of carbonate mineral excavation sites in the central part of the Opole region. In the vast majority of cases, plots of this association developed in reclaimed areas. The majority of diagnostic species for the association was found within surveyed plots, including Verbascum thapsus, V. densiflorum and Bryum argenteum. Taxa characteristic of the alliance were also constantly present, i.e. Daucus carota, Melilotus alba, M. officinalis, Echium vulgare and Erysimum hieracifolium. This association belongs…
Two uncommon fungal species from Italy
2019
Mediterranean forests continue to be an inexhaustible reservoir of fungi of considerable ecological and biogeographical interest. In this paper two rare and/or infrequent species are reported. Boletopsis grisea is a threatened species in Europe while H. subtortum is infrequent.
New and rare species of bryophytes for the territory of St. Petersburg
2012
In total 24 bryophyte species (10 liverworts and 13 mosses) are recorded for the first time for the territory of St. Petersburg and five rare species (Anthoceros agrestis Paton, Fossombronia wondraczekii (Corda) Dumort. ex Lindb., Aloina rigida (Hedw.) Limpr., Dicranella humilis R. Ruthe, Seligeria diversifolia Lindb.) are listed for the territory of St. Petersburg on the basis of old literature data. Data on localities, habitats of all these species and their distribution in St. Petersburg and adjacent territories of Leningrad Region are provided.
Ecological aspects of plants inhabiting Mediterranean cliffs. Challenges and prospects of life in vertical environments
2021
[ES] Esta tesis investiga las oportunidades, desafíos y limitaciones para la investigación en el campo de la ecología vegetal, en el contexto de los acantilados mediterráneos. En concreto, las especies casmofiticas, cuyos hábitats naturales se caracterizan por su acusada pendiente. Las laderas de las montañas de piedra caliza en la proximidad del mar, en la parte central y occidental del área mediterránea se consideran objetos de estudio. Los estudios se llevaron a cabo en los cinturones costeros de montaña de las costas del noroeste de Sicilia y la costa diánica en la Comunidad Valenciana. El primer capítulo, titulado "The complexity of environmental factors: cliff microclimate", investiga…