How well do we know species richness in a well-known continent? Temporal patterns of endemic and widespread species descriptions in the European fauna

2012 ◽  
Vol 22 (1) ◽  
pp. 29-39 ◽  
Author(s):  
Franz Essl ◽  
Wolfgang Rabitsch ◽  
Stefan Dullinger ◽  
Dietmar Moser ◽  
Norbert Milasowszky
2019 ◽  
Author(s):  
Kittipong Chaisiri ◽  
A. Christina Gill ◽  
Alexandr A. Stekolnikov ◽  
Soawapak Hinjoy ◽  
John W. McGarry ◽  
...  

AbstractScrub typhus, caused by a bacterial pathogen (Orientia spp.), is a potentially life-threatening febrile illness widely distributed in the Asia-Pacific region and is emerging elsewhere. The infection is transmitted by the larval stage of trombiculid mites (“chiggers”) that often exhibit low host specificity. Here, we present an analysis of chigger ecology for 38 species sampled from 11 provinces of Thailand and microbiomes for eight widespread species. In total, >16 000 individual chiggers were collected from 1 574 small mammal specimens belonging to 18 species across four horizontally-stratified habitat types. Chigger species richness was positively associated with higher latitudes, dry seasonal conditions, and host maturity; but negatively associated with increased human land use. Human scrub typhus incidence was found to be positively correlated with chigger species richness. The bacterial microbiome of chiggers was highly diverse, with Sphingobium, Mycobacterium, Neisseriaceae and various Bacillales representing the most abundant taxa. Only Leptotrombidium deliense was found to be infected with Orientia. β-diversity, but not α-diversity, was significantly different between chigger species and geographic regions, although not between habitat types. This first field survey of the chigger microbiome provides a framework for future studies on interactions between pathogens and other symbionts in these understudied vectors.


2019 ◽  
Vol 1 (1) ◽  
Author(s):  
Kittipong Chaisiri ◽  
A. Christina Gill ◽  
Alexandr A. Stekolnikov ◽  
Soawapak Hinjoy ◽  
John W. McGarry ◽  
...  

Abstract Background Scrub typhus, caused by a bacterial pathogen (Orientia spp.), is a potentially life-threatening febrile illness widely distributed in the Asia-Pacific region and is emerging elsewhere. The infection is transmitted by the larval stage of trombiculid mites (“chiggers”) that often exhibit low host specificity. Here, we present an analysis of chigger ecology for 38 species sampled from 11 provinces of Thailand and microbiomes for eight widespread species. Results In total, > 16,000 individual chiggers were collected from 1574 small mammal specimens belonging to 18 species across four horizontally-stratified habitat types. Chigger species richness was positively associated with higher latitudes, dry seasonal conditions, and host maturity; but negatively associated with increased human land use. Human scrub typhus incidence was found to be positively correlated with chigger species richness. The bacterial microbiome of chiggers was highly diverse, with Sphingobium, Mycobacterium, Neisseriaceae and various Bacillales representing the most abundant taxa. Only Leptotrombidium deliense was found to be infected with Orientia and another potential pathogen, Borrelia spp., was frequently detected in pools of this species. β-diversity, but not α-diversity, was significantly different between chigger species and geographic regions, although not between habitat types. Conclusion Our study identified several key environmental and host-derived correlates of chigger species richness across Thailand, which in turn impacted on human scrub typhus incidence. Moreover, this first extensive field survey of the chigger microbiome revealed species- and province-level variation in microbial β-diversity across the country, providing a framework for future studies on interactions between pathogens and other symbionts in these understudied vectors.


2001 ◽  
Vol 75 (3) ◽  
pp. 680-696 ◽  
Author(s):  
Ross H. Nehm

Collectively, studies of the structure of Neogene diversity change in tropical American mollusks have lacked 1) species-level analyses within well-established clades; 2) consideration of abundance and sample size on diversity estimates and comparisons; and 3) geographic comparisons within temporal intervals. This study takes all three factors into consideration and compares Miocene to Recent species richness patterns in tropical American marginellid gastropod species within the clade Prunum+Volvarina. Rarefaction analyses of more than 16,000 specimens from more than 500 samples are used to standardize comparisons of species richness through time and space. Species richness in Prunum+Volvarina from the Miocene to the Recent of the Tropical Western Atlantic (TWA) is compared along a latitudinal gradient from north to south (Florida, the Dominican Republic, and Venezuela). Additionally, temporal patterns of diversity change are compared between the TWA and the Tropical Eastern Pacific (TEP: Peru, Ecuador, Colombia, Panama, and Costa Rica).As is the case with most Neogene lineages, the number of marginellid specimens and samples differ significantly through both time and space. Rarefaction analyses of both specimens and samples indicate that: 1) significant geographic differences in species richness were detected between the Miocene, Pliocene, Pleistocene, and Recent of the TWA; 2) temporal patterns of species richness were similar in the northern and southern TWA; 3) from the Miocene to the Recent, marginellid species richness in the TEP has always been significantly less than TWA diversity; and 4) from the Miocene to the Recent, TWA diversity decreased significantly, whereas TEP diversity was stable and low. Separate rarefaction analyses using the numbers of specimens and samples did not always produce concordant results and indicate that the unit of analysis influences estimates of species richness. Discordant specimen/sample rarefaction results may be a product of sample size. Intrinsic ecological and evolutionary differences do not appear to be primary contributors to differences in marginellid species richness between the TEP and TWA.


Paleobiology ◽  
2016 ◽  
Vol 42 (2) ◽  
pp. 269-288 ◽  
Author(s):  
Michael Foote ◽  
Kathleen A. Ritterbush ◽  
Arnold I. Miller

AbstractWe explore the relationships among the geographic ranges of genera, the ranges and positions of their constituent species, and the number of species they contain, considering variation among coeval genera and changes within genera over time. Measuring range size as the maximal distance, or extent, between occurrences within a taxon, we find that the range of the most widespread species is a good predictor of the range of the genus, and that the number of species is a better predictor still. This analysis is complicated by a forced correlation: the range of a genus must be at least as large as that of each of its constituent species. We therefore focus on a second measure of range, the mean squared distance, or dispersion, of occurrences from the geographic centroid, which, by analogy to the analysis of variance, allows the total dispersion of a genus to be compared to the mean within-species dispersion and the dispersion among species centroids. We find that among-species dispersion is the principal determinant of genus dispersion. Within-species dispersion also plays a major role. The role of species richness is relatively small. Our results are not artifacts of temporal variation in the geographic breadth of sampled data. The relationship between changes in genus dispersion and changes in within- and among-species dispersion shows a symmetry, being similar in cases when the genus range is expanding and when it is contracting. We also show that genera with greater dispersion have greater extinction resistance, but that within- and among-species dispersion are not demonstrable predictors of survival once the dispersion of the genus is accounted for. Thus it is the range of the genus, rather than how it is attained, that is most relevant to its fate. Species richness is also a clear predictor of survival, beyond its effects on geographic range.


2007 ◽  
Vol 274 (1618) ◽  
pp. 1567-1574 ◽  
Author(s):  
Kevin J Gaston ◽  
Richard G Davies ◽  
C. David L Orme ◽  
Valerie A Olson ◽  
Gavin H Thomas ◽  
...  

Despite its wide implications for many ecological issues, the global pattern of spatial turnover in the occurrence of species has been little studied, unlike the global pattern of species richness. Here, using a database on the breeding distributions of birds, we present the first global maps of variation in spatial turnover for an entire taxonomic class, a pattern that has to date remained largely a matter of conjecture, based on theoretical expectations and extrapolation of inconsistent patterns from different biogeographic realms. We use these maps to test four predictions from niche theory as to the form that this variation should take, namely that turnover should increase with species richness, towards lower latitudes, and with the steepness of environmental gradients and that variation in turnover is determined principally by rare (restricted) species. Contrary to prediction, we show that turnover is high both in areas of extremely low and high species richness, does not increase strongly towards the tropics, and is related both to average environmental conditions and spatial variation in those conditions. These results are closely associated with a further important and novel finding, namely that global patterns of spatial turnover are driven principally by widespread species rather than the restricted ones. This complements recent demonstrations that spatial patterns of species richness are also driven principally by widespread species, and thus provides an important contribution towards a unified model of how terrestrial biodiversity varies both within and between the Earth's major land masses.


2005 ◽  
Vol 32 (11) ◽  
pp. 2025-2037 ◽  
Author(s):  
Birgitta Malm Renofalt ◽  
Christer Nilsson ◽  
Roland Jansson

Phytotaxa ◽  
2014 ◽  
Vol 160 (1) ◽  
pp. 1 ◽  
Author(s):  
Marcelo Freire Moro ◽  
Eimear Nic Lughadha ◽  
Denis L. Filer ◽  
Francisca Soares de Araújo ◽  
Fernando Roberto Martins

A catalogue is presented of plant names in use in the Caatinga Phytogeographical Domain (CPD), the largest semiarid ecoregion of South America. We compiled all pubished papers we could locate with floristic and/or phytosociological data relating to the CPD and created a database of all site-based surveys, all names reported in these surveys and the basic ecological data associated with each species. We then mapped the names used in survey reports to those currently accepted in Brazil, consulting specialists to resolve taxonomic and nomenclatural issues before synthesizing the data in order to present here a list of all names in use. Thus this compilation represents the taxonomic data in use by generalist botanists on a sub continental scale. Synthesizing the previously dispersed ecological data available for the species, we explored general ecological patterns in the CPD. We also classified each survey as documenting the flora of a specific type of environment within the CPD and compared the general floristic resemblance between different environments within CPD on a biogeographical scale. Rarefaction curves and species richness estimator indices were employed in order to address the question as to whether or not the Caatinga Phytogeographical Domain can be described as well-sampled. To date over 1700 species have been reported in site-based floristic and phytosociological studies in the CPD. Most surveys focused only on woody plants, ignoring the non woody component, but we show here that a large proportion of the plant biodiversity in the Caatinga is comprised of non woody plants. We estimate that 40% of the existing species were not sampled by site-based surveys. Moreover, most of the species in our database were recorded from a single site, while a few species were considered widespread. When comparing the number of widespread species in our dataset to results published for the cerrado savannas, we show that species in Caatinga seems to have a much more restricted distribution than plants in the Cerrado. We present here a catalogue of all plant names recorded and discuss sampling and geographical issues related to the floristic study of Caatinga.


Author(s):  
Luděk Tyšer ◽  
Michaela Kolářová ◽  
Ondřej Tulačka ◽  
Pavel Hamouz

The paper presents species richness and composition of arable weed vegetation in the region of West Bohemia (Czech Republic) in different types of farming (conventional and organic) and grown crops (winter and spring cereals, wide-row crops). During the field survey in the years 2007 to 2017, 105 phytocoenological relevés were recorded. The average species richness in one relevé was significantly higher in organic farming, as well as total weed cover. The lowest species richness was found in wide-row crops. Recently widespread species belonged to the most frequent species in our study. Based on multivariate statistics, the effects of variables on the occurrence of weed species were found as statistically significant. Most of the variability in data was explained by crop, following by type of farming. Weed species of Fabaceae Lindl. family (especially Vicia L.) and many perennial species positively correlated with the organic type of farming. Endangered species were found mainly in organic farming and cereals. Less intensive cultivation with a higher weed cover is beneficial for the promotion of biodiversity.  


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