scholarly journals Biogeographic Patterns of Finnish Crane Flies (Diptera, Tipuloidea)

2012 ◽  
Vol 2012 ◽  
pp. 1-20 ◽  
Author(s):  
Jukka Salmela
Keyword(s):  
Species Richness ◽  
Latitudinal Gradient ◽  
Global Scale ◽  
Mantel Test ◽  
Biogeographic Patterns ◽  
Incidence Data ◽  
Crane Flies ◽  
Richness Pattern ◽  
Freshwater Biota ◽  
Faunistic Composition

Species richness of terrestrial and freshwater biota generally decreases with increasing latitude. Some taxa, however, show an anomalous species richness pattern in a regional or global scale. The aim of this study was to examine (i) regional variation in species richness, (ii) faunistic composition, (iii) occupancy, and (iv) proportions of different distribution types of Finnish crane flies. Analyses were based on incidence data pooled into 20 biogeographical provinces. Finnish crane fly fauna consists of 335 species; the provincial richness varies from 91 to 237. The species richness of all species and saproxylic/fungivorous species decreased with increasing latitude; mire-dwelling crane flies displayed a reversed pattern (Spearman's correlations). Thirty-one species occupied a single province and 11 species were present in all provinces. Provincial assemblages showed a strong latitudinal gradient (NMS ordination) and faunistic distance increased with increasing geographical distance (Mantel test). Nearly half (48%) of the Finnish crane flies are Trans-Palaearctic, roughly one-third (34%) are West Palaearctic, and only 16 and 2% are Holarctic and Fennoscandian, respectively. Endemic Fennoscandian species are discussed in detail; most likely there are no true endemic crane flies in this region.

scholarly journals Species diversity and endemism: testing the mid-domain effect on species richness patterns of songbirds in the Palearctic Region

2008 ◽  
Vol 77 (2) ◽  
pp. 99-108 ◽  
Author(s):  
Mansour Aliabadian ◽  
Ronald Sluys ◽  
Cees S. Roselaar ◽  
Vincent Nijman
Keyword(s):  
Species Richness ◽  
Explanatory Power ◽  
Empirical Support ◽  
Grid Cell ◽  
Distribution Patterns ◽  
Distribution Maps ◽  
Biogeographic Patterns ◽  
Palearctic Region ◽  
Richness Pattern ◽  
Constraint Model

Explanation of the spatial distribution patterns in species richness, and especially those of small-ranged species (endemics), bears relevance for studies on evolution and speciation, as well as for conservation management. We test a geometric constraint model, the mid-domain effect (MDE), as a possible explanation for spatial patterns of species richness in Palearctic songbirds (Passeriformes), with an emphasis on the patterns of small-ranged species. We calculated species richness based on digitised distribution maps of phylogenetic species of songbirds endemic to the Palearctic region. Data were plotted and analyzed over a one degree equal area map of the Palearctic Region, with a grid cell area of 4062 km². The emergent biogeographic patterns were analysed with WORLDMAP software. Comparison of the observed richness pattern among 2401 phylogenetic taxa of songbirds in the Palearctic Region with the predictions of a fully stochastic bi-dimensional MDE model revealed that this model has limited empirical support for overall species richness of Palearctic songbirds. Major hotspots were located south of the area where MDE predicted the highest species- richness, while some of the observed coldspots were in the centre of the Palearctic Region. Although small-ranged species are often found in areas with the highest species richness, MDE models have a very restricted explanatory power for the observed species-richness pattern in small-ranged species. Regions with a high number of small-ranged species (endemism hotspots) may contain a unique set of environmental conditions, unrelated to the shape or size of the domain, allowing a multitude of species to co-exist.

Distribution of lacustrine plankton crustaceans and biogeographic patterns of biodiversity in Chile

Crustaceana ◽  
2021 ◽  
Vol 94 (8) ◽  
pp. 933-950
Author(s):  
Reinaldo Rivera ◽  
Javier Pinochet ◽  
Patricio De los Ríos-Escalante ◽  
Cristián E. Hernández
Keyword(s):  
Species Richness ◽  
Ecological Factors ◽  
Energy Availability ◽  
Biogeographic Patterns ◽  
Landscape Water ◽  
Richness Pattern ◽  
Colonization Dynamics ◽  
Geographical Dispersion ◽  
Adequate Management ◽  
Latitudinal Effect

Abstract The pattern of species richness and its potential causes are fundamental knowledge for an adequate management of biodiversity. In the present study, based on georeferenced lacustrine zooplankton, we evaluated the general species richness pattern and its relationship with hydrographic zonation, assessing four hypotheses: (1) the Rapoport latitudinal effect; (2) geometric restrictions as hard limits to geographical dispersion; (3) nestedness as a measure of the historical dynamics of extinction-colonization; and (4) environmental variables, as a measurement of the habitat as a recent ecological factor. Our results show a heterogeneous species richness pattern, with maxima located between 32-34°S, showing a general decrease towards higher latitudes. However, this pattern does not relate to the Rapoport latitudinal effect or the geometric restrictions. Instead, the pattern is associated with historical extinction-colonization dynamics between the waterbodies and ecological factors such as landscape, water, and energy availability that determine the number of species that these waterbodies can currently support.

Biogeographic patterns of fish species richness in Ontario lakes in relation to historical and environmental factors

1995 ◽  
Vol 52 (7) ◽  
pp. 1462-1474 ◽  
Author(s):  
Nicholas E. Mandrak
Keyword(s):  
Species Richness ◽  
Spatial Autocorrelation ◽  
Fish Species ◽  
Mantel Test ◽  
Partial Mantel Test ◽  
Principal Coordinates Analysis ◽  
Northern Ontario ◽  
Lake Chemistry ◽  
Biogeographic Patterns ◽  
Principal Coordinates

Fish species richness in Ontario lakes was summarized for 80 equal-area quadrats and ranged from 59 species per quadrat in southwestern Ontario to 17 species per quadrat in northern Ontario. Correlograms based on Moran's I coefficient indicated the spatial structure of lake species richness was anisotropic and exhibited a strong south–north gradient of decreasing richness. Relationships among Euclidean distance matrices based on richness, postglacial dispersal, climate, elevation, lake chemistry, and lake morphometry were identified with the aid of the Mantel test and principal coordinates analysis. The presence of spatial autocorrelation may bias matrix correlations; therefore, spatial autocorrelation was removed using the partial Mantel test. The results of the partial Mantel test indicated regional lake species richness was significantly correlated with postglacial dispersal and climate. In particular, the results of principal coordinates analysis identified length of time since deglaciation, length of time covered by glacial lakes, distance from dispersal corridor, and mean annual air temperature as the dominant variables in these data sets.

scholarly journals Global warming is causing a more pronounced dip in marine species richness around the equator

2021 ◽  
Vol 118 (15) ◽  
pp. e2015094118
Author(s):  
Chhaya Chaudhary ◽  
Anthony J. Richardson ◽  
David S. Schoeman ◽  
Mark J. Costello
Keyword(s):  
Climate Change ◽  
Species Richness ◽  
Animal Species ◽  
Latitudinal Gradient ◽  
Marine Species ◽  
Global Scale ◽  
Marine Biodiversity ◽  
Marine Animal ◽  
Pelagic Species ◽  
The Tropics

The latitudinal gradient in species richness, with more species in the tropics and richness declining with latitude, is widely known and has been assumed to be stable over recent centuries. We analyzed data on 48,661 marine animal species since 1955, accounting for sampling variation, to assess whether the global latitudinal gradient in species richness is being impacted by climate change. We confirm recent studies that show a slight dip in species richness at the equator. Moreover, richness across latitudinal bands was sensitive to temperature, reaching a plateau or declining above a mean annual sea surface temperature of 20 °C for most taxa. In response, since the 1970s, species richness has declined at the equator relative to an increase at midlatitudes and has shifted north in the northern hemisphere, particularly among pelagic species. This pattern is consistent with the hypothesis that climate change is impacting the latitudinal gradient in marine biodiversity at a global scale. The intensification of the dip in species richness at the equator, especially for pelagic species, suggests that it is already too warm there for some species to survive.

scholarly journals Species delimitation at a global scale reveals high species richness with complex biogeography and patterns of symbiont association in Peltigera section Peltigera (lichenized Ascomycota: Lecanoromycetes)

Taxon ◽  
2018 ◽  
Vol 67 (5) ◽  
pp. 836-870 ◽  
Author(s):  
Nicolas Magain ◽  
Camille Tniong ◽  
Trevor Goward ◽  
Dongling Niu ◽  
Bernard Goffinet ◽  
...  
Keyword(s):  
Species Richness ◽  
Species Delimitation ◽  
Global Scale ◽  
High Species Richness

scholarly journals Scavenging in the Anthropocene: Human impact drives vertebrate scavenger species richness at a global scale

2020 ◽  
Author(s):  
E Sebastián-González ◽  
JM Barbosa ◽  
JM Pérez-García ◽  
Z Morales-Reyes ◽  
F Botella ◽  
...  
Keyword(s):  
Species Richness ◽  
Human Impact ◽  
Large Scale ◽  
Diversity Index ◽  
Global Scale ◽  
Climatic Conditions ◽  
Ecosystem Functions ◽  
Number Of Species ◽  
Terrestrial Vertebrate ◽  
Latitudinal Patterns

© 2019 John Wiley & Sons Ltd Understanding the distribution of biodiversity across the Earth is one of the most challenging questions in biology. Much research has been directed at explaining the species latitudinal pattern showing that communities are richer in tropical areas; however, despite decades of research, a general consensus has not yet emerged. In addition, global biodiversity patterns are being rapidly altered by human activities. Here, we aim to describe large-scale patterns of species richness and diversity in terrestrial vertebrate scavenger (carrion-consuming) assemblages, which provide key ecosystem functions and services. We used a worldwide dataset comprising 43 sites, where vertebrate scavenger assemblages were identified using 2,485 carcasses monitored between 1991 and 2018. First, we evaluated how scavenger richness (number of species) and diversity (Shannon diversity index) varied among seasons (cold vs. warm, wet vs. dry). Then, we studied the potential effects of human impact and a set of macroecological variables related to climatic conditions on the scavenger assemblages. Vertebrate scavenger richness ranged from species-poor to species rich assemblages (4–30 species). Both scavenger richness and diversity also showed some seasonal variation. However, in general, climatic variables did not drive latitudinal patterns, as scavenger richness and diversity were not affected by temperature or rainfall. Rainfall seasonality slightly increased the number of species in the community, but its effect was weak. Instead, the human impact index included in our study was the main predictor of scavenger richness. Scavenger assemblages in highly human-impacted areas sustained the smallest number of scavenger species, suggesting human activity may be overriding other macroecological processes in shaping scavenger communities. Our results highlight the effect of human impact at a global scale. As species-rich assemblages tend to be more functional, we warn about possible reductions in ecosystem functions and the services provided by scavengers in human-dominated landscapes in the Anthropocene.

scholarly journals A meta-analysis of global avian survival across species and latitude

2019 ◽  
Author(s):  
Micah N. Scholer ◽  
Matt Strimas-Mackey ◽  
Jill E. Jankowski
Keyword(s):  
Latitudinal Gradient ◽  
Meta Analysis ◽  
Survival Rates ◽  
Global Scale ◽  
Geographic Region ◽  
Passerine Birds ◽  
Tropical Birds ◽  
Model Predictions ◽  
Improved Model ◽  
Northern And Southern Hemispheres

AbstractTropical birds are purported to be longer lived than temperate species of similar size, but it has not been shown whether avian survival rates covary with a latitudinal gradient worldwide. Here, we perform a global-scale meta-analysis to investigate the extent of the latitudinal survival gradient. We modeled survival as a function of latitude for the separate northern and southern hemispheres, and considered phylogenetic relationships and extrinsic (climate) and intrinsic (life history) predictors hypothesized to moderate these effects. Using a database of 1,004 estimates from 246 studies of avian survival, we demonstrate that in general a latitudinal survival gradient exists in the northern hemisphere, is dampened or absent for southern hemisphere species, and that survival rates of passerine birds largely account for these trends. We found no indication that the extrinsic climate factors were better predictors of survival than latitude alone, but including species’ intrinsic traits improved model predictions. Notably, species with smaller clutch size and larger body mass showed higher survival. Our results illustrate that while some tropical birds may be longer lived than their temperate counterparts, the shape of the latitude-survival gradient differs by geographic region and is strongly influenced by species’ intrinsic traits.

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