Species and genus richness and assemblage composition of stream caddisflies (Insecta: Trichoptera) vary with latitude in mountain rainforest of Argentina

2019 ◽  
Vol 70 (5) ◽  
pp. 687
Author(s):  
Edgardo J. I. Pero ◽  
Paola A. Rueda Martín ◽  
María C. Reynaga
Keyword(s):  
Latitudinal Gradient ◽  
Aquatic Insect ◽  
Latitudinal Gradients ◽  
Mountain Forest ◽  
Low Latitude ◽  
Study Region ◽  
Assemblage Composition ◽  
Composition And Structure ◽  
Genus Richness ◽  
Rank Abundance

Evidence found in results of studies of latitudinal gradients of benthic macroinvertebrate diversity is variable. This study analysed how species and genus richness and the composition of caddisfly assemblages (Insecta: Trichoptera) vary in Argentinean mountain forest through a latitudinal gradient from 22 to 28°S. Qualitative and quantitative data from 20 stream sites were compared. Assemblage richness and composition were analysed by comparing linear regressions, rank–abundance (RA) curves and non-metric multidimensional scaling (nMDS). Taxonomic richness increased from high to low latitude. RA curves showed changes in assemblage composition and structure across the latitudinal gradient. The nMDS revealed that the composition of the assemblages also changed along the latitudinal gradient. The patterns are similar to those observed in plants and vertebrates from the study region. The results are of particular note because a latitudinal gradient of aquatic insect diversity has rarely been observed in a narrow range.

scholarly journals What drives the latitudinal gradient in open-ocean surface dissolved inorganic carbon concentration?

2019 ◽  
Vol 16 (13) ◽  
pp. 2661-2681 ◽  
Author(s):  
Yingxu Wu ◽  
Mathis P. Hain ◽  
Matthew P. Humphreys ◽  
Sue Hartman ◽  
Toby Tyrrell
Keyword(s):  
Southern Ocean ◽  
High Latitude ◽  
Latitudinal Gradient ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Latitudinal Gradients ◽  
Total Alkalinity ◽  
Global Ocean ◽  
Low Latitude ◽  
Surface Ocean

Abstract. Previous work has not led to a clear understanding of the causes of spatial pattern in global surface ocean dissolved inorganic carbon (DIC), which generally increases polewards. Here, we revisit this question by investigating the drivers of observed latitudinal gradients in surface salinity-normalized DIC (nDIC) using the Global Ocean Data Analysis Project version 2 (GLODAPv2) database. We used the database to test three different hypotheses for the driver producing the observed increase in surface nDIC from low to high latitudes. These are (1) sea surface temperature, through its effect on the CO2 system equilibrium constants, (2) salinity-related total alkalinity (TA), and (3) high-latitude upwelling of DIC- and TA-rich deep waters. We find that temperature and upwelling are the two major drivers. TA effects generally oppose the observed gradient, except where higher values are introduced in upwelled waters. Temperature-driven effects explain the majority of the surface nDIC latitudinal gradient (182 of the 223 µmol kg−1 increase from the tropics to the high-latitude Southern Ocean). Upwelling, which has not previously been considered as a major driver, additionally drives a substantial latitudinal gradient. Its immediate impact, prior to any induced air–sea CO2 exchange, is to raise Southern Ocean nDIC by 220 µmol kg−1 above the average low-latitude value. However, this immediate effect is transitory. The long-term impact of upwelling (brought about by increasing TA), which would persist even if gas exchange were to return the surface ocean to the same CO2 as without upwelling, is to increase nDIC by 74 µmol kg−1 above the low-latitude average.

scholarly journals What drives the latitudinal gradient in open ocean surface dissolved inorganic carbon concentration?

2018 ◽  
Author(s):  
Yingxu Wu ◽  
Mathis P. Hain ◽  
Matthew P. Humphreys ◽  
Sue Hartman ◽  
Toby Tyrrell
Keyword(s):  
Southern Ocean ◽  
High Latitude ◽  
Latitudinal Gradient ◽  
Equilibrium Constants ◽  
Latitudinal Gradients ◽  
Total Alkalinity ◽  
Global Ocean ◽  
Clear Understanding ◽  
Low Latitude ◽  
Surface Ocean

Abstract. Previous work has not led to a clear understanding of the causes of spatial pattern in global surface ocean DIC, which generally increases polewards. Here, we revisit this question by investigating the drivers of observed latitudinal gradients in surface salinity-normalized DIC (nDIC) using the Global Ocean Data Analysis Project Version 2 (GLODAPv2) database. We used the database to test three different hypotheses for the driver producing the observed increase in surface nDIC from low to high latitudes. These are: (1) sea surface temperature, through its effect on the CO2 system equilibrium constants, (2) salinity-related total alkalinity (TA), and (3) high latitude upwelling of DIC- and TA-rich deep waters. We find that temperature and upwelling are the two major drivers. TA effects generally oppose the observed gradient, except where higher values are introduced in upwelled waters. Temperature-driven effects explains the majority of the surface nDIC latitudinal gradient (182 out of 223 μmol kg−1 in the high-latitude Southern Ocean). Upwelling, which has not previously been considered as a major driver, additionally drives a substantial latitudinal gradient. Its immediate impact, prior to any induced air-sea CO2 exchange, is to raise Southern Ocean nDIC by 208 μmol kg−1 above the average low latitude value. However, this immediate effect is transitory. The long-term impact of upwelling (brought about by increasing TA), which would persist even if gas exchange were to return the surface ocean to the same CO2 as without upwelling, is to increase nDIC by 74 μmol kg−1 above the low latitude average.

scholarly journals Post midnight spread-F occurrence over Waltair (17.7° N, 83.3° E) during low and ascending phases of solar activity

2003 ◽  
Vol 21 (3) ◽  
pp. 745-750 ◽  
Author(s):  
K. Niranjan ◽  
P. S. Brahmanandam ◽  
P. Ramakrishna Rao ◽  
G. Uma ◽  
D. S. V. V. D. Prasad ◽  
...  
Keyword(s):  
Solar Activity ◽  
Atmospheric Composition ◽  
Activity Period ◽  
Sunspot Activity ◽  
Low Latitude ◽  
F Region ◽  
Composition And Structure ◽  
Spread F ◽  
Solar Activity Period ◽  
Night Airglow

Abstract. A study carried out on the occurrence of post midnight spread-F events at a low-latitude station, Waltair (17.7° N, 83.3° E), India revealed that its occurrence is maximum in the summer solstice months of the low solar activity period and decreases with an increase in the sunspot activity. The F-region virtual height variations show that 80% of these spread-F cases are associated with an increase in the F-region altitude. It is suggested with the support of the night airglow 6300 A zenith intensity data obtained with co-located ground-based night airglow photometer and electron temperature data from the Indian SROSS C2 satellite that the seasonal variation of the occurrence and probable onset times of the post midnight spread-F depend on the characteristics of the highly variable semipermanent equatorial Midnight Temperature Maximum (MTM).Key words. Ionosphere (ionospheric irregularities; ionosphere atmosphere interactions) Atmospheric composition and structure (airglow and Aurora)

Metabolic asymmetry and the global diversity of marine predators

Science ◽  
2019 ◽  
Vol 363 (6425) ◽  
pp. eaat4220 ◽  
Author(s):  
John M. Grady ◽  
Brian S. Maitner ◽  
Ara S. Winter ◽  
Kristin Kaschner ◽  
Derek P. Tittensor ◽  
...  
Keyword(s):  
Species Richness ◽  
Spatial Patterns ◽  
Marine Mammals ◽  
Phylogenetic Diversity ◽  
Latitudinal Gradient ◽  
Latitudinal Gradients ◽  
Competitive Interactions ◽  
Marine Predators ◽  
Theoretical Predictions ◽  
The Tropics

Species richness of marine mammals and birds is highest in cold, temperate seas—a conspicuous exception to the general latitudinal gradient of decreasing diversity from the tropics to the poles. We compiled a comprehensive dataset for 998 species of sharks, fish, reptiles, mammals, and birds to identify and quantify inverse latitudinal gradients in diversity, and derived a theory to explain these patterns. We found that richness, phylogenetic diversity, and abundance of marine predators diverge systematically with thermoregulatory strategy and water temperature, reflecting metabolic differences between endotherms and ectotherms that drive trophic and competitive interactions. Spatial patterns of foraging support theoretical predictions, with total prey consumption by mammals increasing by a factor of 80 from the equator to the poles after controlling for productivity.

Benthic assemblage composition on subtidal reefs along a latitudinal gradient in Western Australia

2010 ◽  
Vol 86 (1) ◽  
pp. 83-92 ◽  
Author(s):  
D.A. Smale ◽  
G.A. Kendrick ◽  
K.I. Waddington ◽  
K.P. Van Niel ◽  
J.J. Meeuwig ◽  
...  
Keyword(s):  
Western Australia ◽  
Latitudinal Gradient ◽  
Benthic Assemblage ◽  
Assemblage Composition

scholarly journals Latitudinal gradients in intraspecific ecological diversity

2013 ◽  
Vol 9 (6) ◽  
pp. 20130778 ◽  
Author(s):  
Márcio S. Araújo ◽  
Raul Costa-Pereira
Keyword(s):  
Species Diversity ◽  
Latitudinal Gradient ◽  
Latitudinal Gradients ◽  
Ecological Diversity ◽  
Invertebrate Animal ◽  
Niche Variation ◽  
Wide Range ◽  
Global Patterns ◽  
Global Biodiversity ◽  
New Perspective

The increase in the number of species with decreasing latitude is a striking pattern of global biodiversity. An important feature of studies of this pattern up to now has been the focus on species as the fundamental unit of interest, neglecting potential within-species ecological diversity. Here, we took a new perspective on this topic by measuring the degree to which individuals within populations differ in niche attributes across a latitudinal gradient (range: 54.01° S to 69.12° N). We show that 156 populations of 76 species across a wide range of vertebrate and invertebrate animal taxa contain more ecologically diverse assemblages of individuals towards lower latitudes. Our results add a new level of complexity to our understanding of global patterns of biodiversity and suggest the possibility that niche variation is partly responsible for the latitudinal gradients of species diversity.

scholarly journals Composition and structure of fish assemblage from Passa Cinco stream, Corumbataí river sub-basin, SP, Brazil

2012 ◽  
Vol 72 (1) ◽  
pp. 87-96
Author(s):  
AL Carmassi ◽  
G Rondineli ◽  
FC Ferreira ◽  
FMS Braga
Keyword(s):  
Species Distribution ◽  
Fish Assemblage ◽  
Altitudinal Gradient ◽  
Habitat Diversity ◽  
Important Species ◽  
Assemblage Composition ◽  
Gill Nets ◽  
Composition And Structure ◽  
Significant Difference ◽  
Richness Index

The aim of this work was to determine the composition of the fish assemblage of Passa Cinco stream and verify changes in their structure on the altitudinal gradient. Six samples were performed at five different sites in Passa Cinco stream (from the headwater, at order two, to its mouth, at order six), using an electric fishery equipment and gill nets in May, July, September and November of 2005 and January and March of 2006. The indices of Shannon's diversity, Pielou's evenness and Margalef's richness were quantified separately considering the different fishery equipment (nets versus electric fishery equipment). An ANOVA was used to compare samples collected in relation to values of abundance, diversity, evenness and richness. The representativeness of the species was summarised by their average values of abundance and weight. We captured 5082 individuals distributed into 61 species. We observed a trend of increasing diversity, richness and evenness of species from site 1 to 3, with further decrease in sites 4 and 5. The values found for habitat diversity also followed this pattern. Significant differences were found for all three indices considering the electric fishery samples. For individuals caught with nets, only the richness index showed a significant difference. Characidium aff. zebra was an important species in the headwater and transition sites and Hypostomus strigaticeps in middle-lower course sites. Despite the small extension of the Passa Cinco stream, environments structurally well defined were evidenced by the species distribution and assemblage composition along the gradient.

Steep latitudinal gradients of thermospheric composition during magnetic storms: a possible formation mechanism

1995 ◽  
Vol 13 (3) ◽  
pp. 277-284
Author(s):  
M. G. Skoblin ◽  
M. Förster
Keyword(s):  
Joule Heating ◽  
Latitudinal Gradient ◽  
Local Heating ◽  
Meridional Wind ◽  
Auroral Oval ◽  
Magnetic Storms ◽  
Latitudinal Gradients ◽  
Time Interval ◽  
Characteristic Time Scale ◽  
Middle Latitudes

Abstract. Mass spectrometer satellite observations show that a narrow region with steep latitudinal gradients of neutral composition is formed in the subauroral winter thermosphere during magnetic storms. In order to analyze the relative importance of individual terms in the continuity equation for atomic oxygen, a two-dimensional model was used to simulate the thermospheric disturbance formation in response to intense Joule heating imposed in the auroral oval. Such an approach allowed three characteristic zones to be distinguished in the high-latitude thermosphere at heights of about 250 km. It was shown that vertical transport is of greatest importance within the local heating region. Horizontal transport dominates at subauroral latitudes near the mid-night edge of the auroral oval. Propagation of the disturbances to middle latitudes is prohibited near the noon edge of the oval by a strong counteraction of a poleward meridional wind. Here is a "relaxation zone" defined as the region which is spread to the equator from the boundary between the local heating area and the subauroral zone in the noon sector LT. It is at this boundary that composition distributions with steep latitudinal gradient are formed within the first few hours of Joule heating source action. Perturbations transported to middle latitudes during the periods when the meridional wind is directed equatorward begin to relax in this zone with a characteristic time scale of about 7 h, independent of season. However, in winter, composition at subauroral latitudes recovers to unperturbed N2/O values before the wind again turns equatorward, giving rise to a distribution with steep latitudinal gradient recovering. In summer, a complete relaxation cannot be reached due to a shorter time interval with poleward wind and a larger disturbance amplitude. These two factors result in an effective smoothing of the initial steep gradient and a more regular latitudinal distribution of composition is observed in the summer thermosphere.

Analysis of Forest Resource Change in Mao’er Mountain Forest Farm Based on GIS

2010 ◽  
Vol 113-116 ◽  
pp. 1250-1255
Author(s):  
Tie Dong Liu ◽  
Wen Feng Gong ◽  
Wei Hong Wang
Keyword(s):  
Spatial Distribution ◽  
Agricultural Land ◽  
Forest Type ◽  
Forest Resources ◽  
Geographical Information ◽  
Mountain Forest ◽  
Forest Resource ◽  
Forest Land ◽  
Study Region ◽  
Mature Forest

This paper, based on the forest map of Mao’er Mountain in 1983 and forest inventory sub-compartment database of Mao’er Mountain in 2004, and with the support of geographical information system (GIS), presents the results of study of forest resource change in the periods, which reflected the change of forest type spatial distribution. Furthermore, this study focuses on the construction and present situation of dynamic forest resource by overlaying the forest resource distribution with DEM in which the vectorization of topographical maps was made by using the vector data for creating the digital elevation model (DEM). The results demonstrate that the area of study region decreased to 216 hm2; and the area of open forest land, new afforestation, non-standing forest, farmland and wetland were decreased; the area of forest land, rivers and lakes, agricultural land and the road land are increasing. Meanwhile, it also indicts that the construction of forest resources was not reasonable, in which the proportions of midlife and near-mature forest are larger, the stocks of midlife and near-mature forest increases, and the stock of mature forest decreased greatly. Finally, the study focuses on the forest resource spatial distribution by overlay analysis combined DEM with forest resources construction, which aimed to adjust the current unreasonable situation for the sustainable management of forest resources in the future.

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