Search results for "rare species"
showing 10 items of 49 documents
2019
A central prediction of niche theory is that biotic communities are structured by niche differentiation arising from competition. To date, there have been numerous studies of niche differentiation in local ant communities, but little attention has been given to the macroecology of niche differentiation, including the extent to which particular biomes show distinctive patterns of niche structure across their global ranges. We investigated patterns of niche differentiation and competition in ant communities in tropical rainforests, using different baits reflecting the natural food spectrum. We examined the extent of temporal and dietary niche differentiation and spatial segregation of ant com…
Population Persistence and Offspring Fitness in the Rare Bellflower Campanula Cervicaria in Relation to Population Size and Habitat Quality
2000
Data from several animal species and a few plant species indicate that small populations face an elevated risk of extinction. Plants are still underrepresented in these studies concerning the relation between population size and persistence. We studied the effect of population size on persistence among natural popu- lations of the rare bellflower Campanula cervicaria in Finland. We monitored 52 bellflower populations for 8 years and found that the mean population size decreased from 24 to 14 during this period. Small popula- tions with # 5 individuals were more prone to losing all fertile plants than were larger ones. Reduction in population size was nevertheless unrelated to the degree of …
Fuzzy quantification of common and rare species in ecological communities (FuzzyQ)
2021
International audience; 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.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 rarity-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 probab…
Species richness and food web structure of soil decomposer community as affected by the size of habitat fragment and habitat corridors
2005
While most ecologists agree that the effects of fragmentation on diversity of organisms are predominantly negative and that the scale of fragmentation defines their severity, the role of habitat corridors in mitigating those effects still remains controversial. This ambiguousness rests largely on various difficulties in experimentation, a problem partially solved in the present paper by the use of easily manipulated soil communities. In this 2.5-year-long field experiment, we investigated the responses of soil decomposer organisms (from microbes to mesofaunal predators) to habitat fragment size, in the presence or absence of habitat corridors connecting the fragments. The habitat fragments …
A new rare species of Oedipoda Latreille, 1829 (Orthoptera: Acrididae) from South Italy
2019
Oedipoda cynthiae n. sp. (Orthoptera: Acrididae: Oedipodinae) is described from Apulia (South Italy). In the past, the same population here considered had been assigned to O. miniata and later to O. charpentieri. Morphological features, biogeographical considerations, and a preliminary molecular analysis confirm that this population must be assigned to a new species, which is described and illustrated here.
Cetacean strandings and museum collections: A focus on Sicily island crossroads for mediterranean species
2021
The study examined the extent of the cetacean strandings in Italy, with a particular focus on Sicily Island. The paper aimed to contribute to the description of a pattern that contemplates the “regular and rare” cetacean species passage along the Sicilian coast. The estimate of marine cetacean strandings was extrapolated from the National Strandings Data Bank (BDS—Banca Dati Spiaggiamenti) and evaluated according to a subdivision in three coastal subregions: the Tyrrhenian sub-basin (northern Sicilian coast), the Ionian sub-basin (eastern Sicilian coast), and the Channel of Sicily (southern Sicilian coast). Along the Italian coast, more than 4880 stranding events have been counted in the pe…
Sampling effort and information quality provided by rare and common species in estimating assemblage structure
2020
Made available in DSpace on 2020-12-12T01:06:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-03-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Academy of Finland Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Reliable biological assessments are essential to answer ecological and management questions but require well-designed studies and representative sample sizes. However, large sampling effort is rarely possible, because it demands large financial resources and time, restricting the number of sites sampled, the duration of the study and the sampling effort at each site. In…
Response of soil mites (Acari, Mesostigmata) to long-term Norway spruce plantation along a mountain stream
2018
During the nineteenth and twentieth centuries, coniferous monocultures were introduced, replacing natural broadleaved forests in Central Europe, mainly for economic benefits. In the mountains, Norway spruce [Picea abies (L.) H. Karst] was introduced in large areas previously covered with beech forests and also in natural riverside habitat corridors such as river valleys, despite its negative impact on the soil environment by e.g. organic matter accumulation, decrease of soil pH and changes in C/N ratio. We aimed to check how long-term Norway spruce plantations affect species richness and diversity of soil mites along a mountain river in former mixed and broadleaved forests. The study, based…
Post-fire beetle succession in a biodiversity hotspot: Białowieża Primeval Forest
2020
Abstract Fires can heavily impact forest ecosystems but fire consequences for animal communities at burned and control sites are rarely investigated in natural forests. Here we present a 10-year study of post-fire beetle succession in natural ecosystem of Bialowieza Primeval Forest, Poland, being a hotspot for beetle fauna. We sampled beetles at burned and unburned (control) sites and compared local alpha and regional gamma diversity between treatments and over time. In total, 27,958 individuals belonging to 630 beetle species were recorded. Average species richness (alpha diversity) and density per sample was higher in burned forest than in control sites, and this difference was especially…
An Enigmatic European Harvestman (Opiliones): New Record and Redescription of Dicranopalpus larvatus (Canestrini, 1874)
2019
Dicranopalpus larvatus is redescribed based on type material. Recent first findings of this rare species on Sardinia enable to provide the essential morphological characters. Original drawings are presented with emphasis on penial and pedipalpal morphology. Dicranopalpus larvatus is a small, short-legged, ground-dwelling species endemic to Italy that matures in autumn and winter and has completed its life cycle in April. Additional information on phenology, life cycle, ecology, distribution and systematic position is given.