scholarly journals Ecology of sandflies (Diptera: Psychodidae) in a restricted focus of cutaneous leishmaniasis en Northern Venezuela: I. Description of the study area, catching methods and species composition

1987 ◽  
Vol 82 (1) ◽  
pp. 119-124 ◽  
Author(s):  
M. Dora Feliciangeli

A study on the ecology of phlebotomine sandfly fauna in a restricted focus of cutaneous leishmaniasis in northern Venezuela was undertaken in order to investigate the species responsible for the transmission. The study area and catching methods for phlebotomine sandflies are described. A total of 9,061 females and 1,662 males were collected during a year-term study. 12 species of Lutzomya and 1 species of Brumptomya sp. were identified. Absolute and relative abundance and ocurrence for each species were determined. The rel ative occurrence allowed to distinguish the common species, viz. L. panamensis, L. ovallesi, L. gomezi, L. tinidadensis, L. atroclavata, L. cayennensis, L. shannoni and L. olmeca bicolor from the rare species vis., L. punctigeniculata, L. rangeliana, L. evansi and L. dubitans. General comments on the species composition of the sandfly fauna in this locality are made.

1987 ◽  
Vol 82 (1) ◽  
pp. 125-131 ◽  
Author(s):  
M. Dora Feliciangeli

The ecology of phlebotomine sandflies in an endemic focus of cutaneous leishmaniasis in Northern Venezuela (San Esteban, Carabobo State) was investigated through a year-term study. Three different habitats: viz. a house, a pridomestic area and a sylvatic area, were covered and the species composition, the abundance and occurrence of each species were analyzed in relation to the habitats, catching methods and hour of catching. L. panamensis, L. gomezi and L. ovallesi are the species which bite man, although almost exclusively at night. All of them hide by day and are common in the sylvatic area. Moreover, L. panamensis and L. gomezi successfully approach the house and seem to settle in the peridomestic area. L. shannoni and L. olmeca bicolor also approach and accidentally bite man. L. trinidadensis, L. atroclavata and L. cayennensis are the common non-antrhopophilic species in the area.


1959 ◽  
Vol 91 (1) ◽  
pp. 15-28 ◽  
Author(s):  
Franklin B. Lewis

Early in the course of a study of the dipteran family Ceratopogonidae,it was realized that very little was known about the species composition, both in numbers and kind, in the state of Connecticut. Consequently a sltudy was set up to determine the species present and the relative abundance of the more common forms. The results of this study are presented in this paper.


1985 ◽  
Vol 63 (8) ◽  
pp. 1870-1879 ◽  
Author(s):  
Carlos Galindo ◽  
Charles J. Krebs

In this study we investigated the influence of competitive interactions on the use of habitats and relative abundance of deer mice (Peromyscus maniculatus). If interspecific competition is influencing the habitat use and relative abundance of deer mice, then removal or introduction of potential competitors will change habitat use and abundance of this species. During the first field season we removed meadow voles (Microtus pennsylvanicus) to look at the effect on the contiguous population of deer mouse. The removal of one species had no effect on the other species' distribution or demography. In the second field season, meadow voles declined to very low numbers and we used their natural fluctuation as a removal experiment. Deer mouse populations were not affected even when the natural decline of meadow voles was more effective in maintaining the sedge meadow free of voles than the previous removal manipulation was. During the 3rd year, meadow voles colonized two areas of forest where deer mice had been alone the previous two field seasons. Red-backed voles (Clethrionomys rutilus), in turn, increased from very low numbers in four grids. Neither meadow voles nor red-backed voles affected the spatial distribution or abundance of deer mice. The results of this study indicate that competitive interactions have no influence on the use of habitats and relative abundance of the common species of small mammals in the southwestern Yukon.


1981 ◽  
Vol 59 (6) ◽  
pp. 1026-1033 ◽  
Author(s):  
James W. Moore

Collections of benthic algae were made in an isolated subarctic lake during July and August 1975. Samples were taken from 30 stations situated at depths of 0.1 to 35 m. The number of species associated with sediments declined with depth from 66 to 22 m. Achnanthes minutissima, Navicula pupula, Cymbella spp., and Nostoc pruniforme reached greatest relative abundance in shallow water whereas Nitzschia palea and Nitzschia dissipata were relatively common below 20 m. Amphora ovalis, Gyrosigma spenceri, and Tabellaria flocculosa did not exhibit a consistent distribution pattern. Standing crops of the epipelon ranged from3 × 106 cells cm−2 (8.5 × 10 μm3 cm−2) at a depth of 0.1–5 m to8 × 103 cells cm−2 (7 × 106 μm3 cm−2) below 20 m. Low light levels, and to a lesser degree, temperature were the most important factors influencing the diversity, species composition, and density of the epipelon in deep water.The epipsammic community consisted of 10 species at all depths. Although Achnanthes pinnata was rare in deep water, the relative abundance of other common species (Amphora ovalis var. pediculus, Fragilaria construens var. venter, and Achnanthes minutissima) was constant at all stations. Standing crops varied from 3.5 × 104 cells cm−2 (39 × 106 μm3 cm−2) at 0.1–5 m to0.3 × 104 cells cm−2 (0.3 × 106 μm3 cm−2) below 20 m. Although low light levels probably controlled densities in deep water, physical characteristics of the substrate determined the diversity and species composition of the community.


1985 ◽  
Vol 224 (1234) ◽  
pp. 115-130 ◽  

Simulation techniques are used to generate random communities of hoverflies that can be com pared with observed communities: both the species composition and morphological size ratios are compared. Patterns of morphology are also examined through the study of size ratios within taxa. Three sites were surveyed, two man-made garden habitats, and one ancient woodland. The man-made habitats contained assemblages of species indistinguishable from species assembled randomly from those present in the county (area = 3400 km 2 ) as a whole, given the assumptions of the random model. The ancient woodland site contained significantly fewer species in common with the man-made habitats than expected from the random model. Size ratios (of both absolute and relative proboscis length) show a similar pattern, with non-random (constant) ratios observed among the common species in ancient woodland. Significantly constant proboscis length ratios were detected in two genera, Eristalis and Platycheirus . In the former, these are due to regular ratios of general body size. In Platycheirus , species have significantly regular differences in relative as well as absolute proboscis length.


1757 ◽  
Vol 50 ◽  
pp. 845-855 ◽  

Dear Sir, Those rare and very extraordinary new species of Barnacles, which you have lately received from abroad, are so different from any of the common species, that I have seen, that I was resolved to inquire into the nature of an animal, which, like a Proteus, appears in so many different shapes or coverings in different parts of the world.


2021 ◽  
Author(s):  
Daniel P. Cariveau ◽  
Michael Roswell ◽  
Tina Harrison ◽  
Mark A. Genung ◽  
Jason Gibbs ◽  
...  

Installing pollinator habitat is a ubiquitous conservation tool, but little is known about which pollinator taxa require support, or which benefit from habitat installations. We studied the response of rare and common bees to pollinator habitat enhancement. We used independent regional datasets to designate bee species as common or rare based on their rank according to one of three metrics: a) site occurrence frequency, b) local relative abundance, and c) geographic range size. We asked whether the abundance or richness of rare and common bees were greater in pollinator habitat, relative to old-field controls. Because we used an arbitrary, quantile-based cutoff to categorize species rarity, we conducted sensitivity analysis and controlled for rarity classification errors with a null model. With this null model, we determined whether rare and/or common species responded to pollinator habitat disproportionately, compared to the expectation for "typical" bee species. We found that the number of individuals and of species designated as rare based on local relative abundance was greater in pollinator habitat enhancements. The number of individuals from bee species designated as rare based on site occurrence was lower in pollinator habitat enhancements, but the number of species was not clearly different between habitat types. We did not find a clear positive nor negative effect of habitat enhancement for species designated rare based on geographic range size. For all three rarity metrics, common species increased in abundance and richness in pollinator habitat relative to controls. Null models indicated that in most cases, neither rare nor common species disproportionately benefited from pollinator habitat. Synthesis and Applications: Our results suggest that pollinator habitat can lead to an increase in the abundance and richness of bees, including species that are rare and that are common. However, rare species appeared to respond differently than typical species, and depending on how species were classified as rare, could display muted or even negative responses to habitat enhancement. Targeting rare species with specific floral resources or unique habitat types may lead to better outcomes for rare and threatened species.


2012 ◽  
Vol 64 (2) ◽  
pp. 93-108 ◽  
Author(s):  
Zofia Rzymowska ◽  
Teresa Skrajna

The aim of the study was to characterize and analyze the segetal flora of the Łuków Plain. The study was carried out from 2003 to 2006 in 182 towns and villages. Vascular flora of the arable fields in the area under study consists of 305 species belonging to 39 families and 168 genera. The analysed flora is characterised by the prevalence of native species (64.6%) over alien species (35.4%). Archaeophytes dominate among anthropophytes, whereas meadow species are the most frequent in the group of apophytes. Annuals and biennials show a slight prevalence over perennials. The analysis of the life-form categories shows the dominance of therophytes (52.8%) as well as a relatively high share of hemicryptophytes (34.4%) and geophytes (12.5%). In the analysed flora, rare and very rare species constitute a vast majority (61.7%), whereas the common and very common species reach 13.1%.


2016 ◽  
Author(s):  
Glenda Yenni ◽  
Peter Adler ◽  
Morgan Ernest

Understanding why so many species are rare yet persistent remains a significant challenge for both theoretical and empirical ecologists. Yenni, Adler, and Ernest (2012) proposed that strong negative frequency dependence causes species to be rare while simultaneously buffering them against extinction. This hypothesis predicts that, on average, rare species should experience stronger negative frequency dependence than common species. However, it is unknown if ecological communities generally show this theoretical pattern, or if rarity is primarily determined by other processes that overwhelm the effects of strong negative frequency dependence. We discuss the implications of this mechanism for natural communities, and develop a method to test for a non-random relationship between negative frequency dependence and relative abundance, using species abundance data from 90 communities across a broad range of environments and taxonomic groups. To account for biases introduced by measurement error, we compared the observed correlation between species relative abundance and the strength of frequency dependence against expectations from a randomization procedure. In approximately half of the analyzed communities, rare species showed disproportionately strong negative frequency dependence compared to common species. Specifically, we found a pattern of increasingly strong negative frequency dependence with decreasing relative abundance. Our results suggest that strong negative frequency dependence is a signature of both rarity and persistence for many species in many communities.


2010 ◽  
Vol 24 (2) ◽  
pp. 407-413 ◽  
Author(s):  
Igor Aurélio Silva ◽  
Marcus Vinicius Cianciaruso ◽  
Marco Antônio Batalha

We examined the species abundance distribution (SAD) of plant communities in: (1) a wet grassland, waterlogged throughout most of the year; (2) a seasonal savanna, with an annual dry season; and (3) a hyperseasonal savanna, with alternating drought and waterlogging over the year. We searched for differences in the abundance distributions of all species, as well as of the common and rare species. We tested whether the SADs fitted the lognormal, log-series, power fraction, and random assortment models. We found that environmental constraints may reduce the evenness of plant communities and change the SADs in savannas. We observed a lognormal abundance distribution in the wet grassland and a random abundance distribution in the hyperseasonal cerrado. The SAD of the seasonal savanna did not follow any model. The common species in the three communities were better fitted by the lognormal model. The rare species in the wet grassland and the hyperseasonal cerrado were better fitted by the random assortment model. The SAD of the rare species of the seasonal savanna did not follow any model. Seasonality seems to modify the lognormal distribution of the overall plant community, generating abundance distributions indistinguishable from random. However, differential community structuring between common and rare species may not be affected by seasonality. The different signatures of the abundance distributions of common and rare plants indicate that composite models are better predictors for SADs in savannas.


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