Causality of the Relationship between Geographic Distribution and Species Abundance

2010 ◽  
Vol 85 (1) ◽  
pp. 3-25 ◽  
Author(s):  
Michael Krabbe Borregaard ◽  
Carsten Rahbek
2020 ◽  
Vol 3 (2) ◽  
pp. a18-25
Author(s):  
AHMAD FITRI AZIZ ◽  
CHARLIE JUSTIN MERGIE LAMAN

The Energy Equivalence Rule (EER) is an unresolved issue in ecology. This rule states that the amount of energy used for each species in a population is independent of its body size. A study on the relationship between abundance and body size of bird assemblages was conducted in Western Sarawak. Abundance data of bird assemblages from seven selected sites in Western Sarawak were used to produce a regression line of log absolute species abundance versus log average body mass. Data from all selected sites were combined to represent bird assemblages in Western Sarawak and the slope produced was -0.216. The slopes obtained for each site were 0.808, -0.080, -0.258, -0.067, -0.161, -0.072 and -0.237, respectively. Statistical analysis shows that the slope of combined data did not differ significantly from -0.75, as expected under the EER. Thus, this study shows that the EER can be applied as a general rule of community structure of bird assemblages in Western Sarawak.


2019 ◽  
Vol 14 (1) ◽  
pp. 34-39
Author(s):  
Виктор Мелихов ◽  
Viktor Melihov ◽  
Евгений Комаров ◽  
Evgeniy Komarov ◽  
Ольга Комарова ◽  
...  

The article presents materials of perennial (1988–2017) studies on solving problems of stabilizing the phytosanitary situation in irrigated agrocenoses. The paper presents the results of studying the species abundance and insects, the patterns of their change under the influence of irrigation in the Lower Volga region. The effect of irrigation on the change in environmental conditions by the parameters of productivity of agrobiocenoses and microclimate is shown. The difference in air temperature in irrigated by sprinkling and non-irrigated agrocenoses immediately after watering reaches 7-8° C. In general, during the growing season, the average daily air temperatures in the irrigated agrocenosis were 2-4° C lower, compared to the non-irrigated. More mesophytic microclimatic conditions, which are formed under the influence of irrigation, are the leading factor determining the increase in the biodiversity of the entomocomplexes of irrigated agrocenoses due to an increase in species abundance and the number of mesophilic and hygrophilic insects. An increase in species diversity and abundance of meso-and hygrophilic in irrigated agricultural landscapes due to the emergence of new micro-sites (canals, spillways, storage ponds, etc.) is also shown. The formation of irrigated conditions in poly-dominant entomological communities, which increase the balance of the agroecosystem, including by optimizing its trophic structure. The changing ecological situation in irrigated agricultural landscapes determines the cultivation of plants with optimized physiological indicators, and the biological characteristics of the development of harmful and beneficial insects change under irrigation conditions. All this directly affects the relationship between phytophages and plants, as well as their survival, fertility, life expectancy of individual phases and other biological features of populations. It is noted that on irrigated crops there is a more favorable relationship between entomophages and pests, making it possible to self-regulate the entomofauna due to increased activity of entomophages. This creates a real opportunity to save the crop and reduce the pesticide load by 40-50% on irrigated crops.


Author(s):  
Artem Y. Sinev ◽  
Henri J. Dumont

By taking Flavalona gen. nov. out of Alona s.l. (Cladocera: Anomopoda: Chydoridae), the last major clade has now been removed from this polyphyletic assemblage. Flavalona gen. nov. is a monophylum defined by having three, rarely two connected head pores and slit-shaped, rarely rounded lateral head pores. Postabdomen rather long, distally narrowed, with robust marginal denticles and weakly developed lateral fascicles of setules. End-claw weakly curved and with short basal spine. Male postabdomen with gonopores opening at the end of a penis-like outgrowth. Trunk limbs: exopodite of P2 with seta; inner portion of P4 with flaming-torch shaped setae; P5 with filter plate of three setae; P6 a large simple lobe. The relationship of the new genus with other Aloninae remains to be determined. A key to the 11 species of the genus is provided and a discussion of their geographic distribution and habitat type is given.


Ecosphere ◽  
2019 ◽  
Vol 10 (5) ◽  
Author(s):  
Murilo Dantas de Miranda ◽  
Luís Borda‐de‐Água ◽  
Henrique Miguel Pereira ◽  
Thomas Merckx

2001 ◽  
Vol 75 (4) ◽  
pp. 373-383 ◽  
Author(s):  
A. Šimková ◽  
P. Sasal ◽  
D. Kadlec ◽  
M. Gelnar

Dactylogyrid species (Monogenea) communities were studied in roach, Rutilus rutilus, collected from two localities in the basin of Morava river, Czech Republic, during the period from April to November 1997 and March to September 1998 to determine the effect of water temperature on parasite abundance, species richness and diversity. Dactylogyrid species were found to co-occur on the gills of roach with up to six species found on the same host individual. Nine dactylogyrid species were identified with the abundance of each reaching a very low level. Niche size was considered to increase with species abundance even when water temperature was high. There was a strong effect of water temperature on abundance of the common dactylogyrid species (D. crucifer, D. nanus, D. rutili and D. suecicus) as well as of the rare species D. rarissimus. The temporary occurrence of the rare species was found without any temperature effect. Water temperature did not affect the relationship between abundance and niche size. Niche size increased with abundance, even when the water temperature was high, which suggests that negative interspecific interactions are not important within dactylogyrid communities.


2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Sara Hayee ◽  
Naveed Akhter ◽  
Abdul Qayyum Khan Sulehriya

Rotifers are zooplanktons that react more sharply to the environmental changes. Objective:To better understand the community composition of rotifers in Safari Zoo Lake, Lahore, PakistanMethods:We collected 16 water samples on monthly basis, dividing lake into four major sites: northern,southern, eastern, and western sites. Each of these was further subdivided into four locations, for a totalof 16 sampling sites. A total 23 rotifer species were recorded from the lake with Brachionus calyciorushaving maximum abundance. A species abundance curve was plotted between months and number ofspecies of rotifers indicating their lowest and highest abundance through the study period.Results:A Cluster Analysis yielded three main groups of closely related species including species likeBrachionus quadridentatus, Synchaeta stylata and Brachionus calyciorus etc. We used a PrincipalComponent Analysis (I and II) to study variation in the rotifer community on a seasonal basis and amongsampling sites. A biplot of Principal Component Analysis (PCA I) reected the relationship of rotifers withthe months. Some of the species showed a positive positive relationship, while others showed negativeone. PCA II was plotted between months and physico-chemical parameters showing their negative andpositive relations.Conclusion:We conclude that a lesser replacement of fresh water, increased density of waterfowl, reptilia andsolid waste left over during boating has resulted in eutrophication of lake leading to overall low diversity ofrotifers observed.


1964 ◽  
Vol S7-VI (4) ◽  
pp. 529-534
Author(s):  
Charles Mangold ◽  
R. Enay ◽  
Pierre Dominjon

Abstract The recent discovery of lower Bathonian (upper middle Jurassic) ammonites at several places in the Bugey region of the southern Jura mountains of eastern France resolves the problem of the relationship of the Bajocian to the Bathonian in this key region. Fauna of upper Bajocian (lower middle Jurassic) and middle and upper Bathonian had long been known but lower Bathonian was unknown. One bed is particularly rich in a varied fauna of ammonites, pelecypods, gastropods, and echinoderms in a remarkable state of preservation. The faunal association shows the coexistence of the forms of the Zigzag beds of England and the Wuerttembergicus beds of Germany, thus confirming the homology of these two horizons. The geographic distribution of type genera of the lower Bathonian in western Europe permits the identification of two faunal domains overlapping in Lorraine and the northern Jura mountains as well as the Bugey region. The genus Zigzagiceras extends from southern England through Switzerland, the Jura mountains, and the Basses-Alpes to Sicily, and also has been found in Portugal. The western limit of the species Parkinsonia (Oraniceras) wuerttembergica occurs in Germany, Lorraine, the Jura mountains, and Sicily. It appears that the genera Morphoceras and Ebrayiceras may have an even greater distribution.


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