Power Fraction: A New Explanation of Relative Abundance Patterns in Species-Rich Assemblages

Oikos ◽  
1996 ◽  
Vol 75 (3) ◽  
pp. 543 ◽  
Author(s):  
Mutsunori Tokeshi
Keyword(s):  
Relative Abundance ◽  
Abundance Patterns ◽  
Power Fraction

Distribution and Relative Abundance Patterns of Columbids in Puerto Rico

The Condor ◽  
1992 ◽  
Vol 94 (1) ◽  
pp. 224-238 ◽  
Author(s):  
Frank F. Rivera-Milan
Keyword(s):  
Puerto Rico ◽  
Relative Abundance ◽  
Abundance Patterns

scholarly journals Biogeography of the Cretaceous / Tertiary planktic foraminiferal faunal transition

1992 ◽  
Vol 6 ◽  
pp. 193-193
Author(s):  
Norman Macleod ◽  
Gerta Keller
Keyword(s):  
Relative Abundance ◽  
High Latitude ◽  
Mirror Image ◽  
Abundance Patterns ◽  
Biogeographic Provinces ◽  
Stable Isotopic ◽  
Isotopic Studies ◽  
Global Cooling ◽  
Northern High Latitude ◽  
Southern High Latitude

Quantitative analysis of a high resolution latest Maastrichtian through Danian planktic foraminiferal database reveals that degrees of endemism characterizing tropical Tethyan and both northern and southern high latitude faunas throughout this interval are much lower than previously supposed. In terms of temporal patterns in the relative abundance of cosmopolitan species, the transition from the diverse globotruncanid-dominated late Maastrichtian assemblage (I), characterizing the lower portion of the A. mayaroensis / P. deformis zones prior to the base of Chron 29, to the diverse globigerinid-dominated Danian assemblage (V) found in Zone P1c and above, takes place through the successive rise and fall of at least three intermediate faunal associations. These include: a mixed assemblage (II) that delineates an interval from the base of Chron 29 to lowermost Danian Zone PO and is dominated by heterohelicids, hedbergellids, and globigerinelloids; a guembelitrid-dominated assemblage (III) that ranges through lower Danian zones P0 - P1a; and a chiloguembelinid-dominated assemblage (IV) that characterizes lower Danian zones P1a through P1b.Species whose differential relative abundances identify them as more or less endemic to a northern high latitude biogeographic province include Guembelitria danica (assemblage III), Chiloguembelitria waiparensis (assemblage IV), and Eoglobigerina danica (assemblage V), while southern high latitude forms with endemic abundance acmes include C. waiparensis (assemblage III) and several globigerine species (e.g., Globigerina extensa, Igorina spiralis, Globigerina aequiensis, Globigerina chasconoma). Tropical tethyan abundance endemics include Heterohelix navarroensis and Pseudoguembelina costulata (fauna II), along with both Parvularugoglobigerina eugubina and Woodringina hornerstownensis (assemblage IV). Overall, levels of planktic foraminiferal endemism were quite low throughout the upper Maastrichtian A. mayaroensis / P. deformis zones, across the K/T boundary, and into the Danian Zone P0. Endemism increased gradually throughout zones P1a and P1b with the addition of species to both northern high latitude and tropical tethyan biogeographic provinces, and then increased much more substantially in Zone P1c with the addition of the southern high latitude globigerine species.Our analysis has also uncovered several instances of dramatic abundance increases for individual taxa occurring significantly earlier in the southern high latitudes (e.g., Chiloguembelina waiparensis). Associated with these diachronous relative abundance patterns, stable isotopic studies indicate that environmental conditions (e.g., temperature, organic productivity) over this K/T transition interval were more stable in the southern ocean than in tropics. Finally, our data reveals a distinct difference and mirror-image ordering in both the disappearance and successive reappearance of the planktic foraminiferal test morphotypes (e.g., keeled trochospires, globigerine trochospires, forms with serially arranged chambers) that prevailed in each faunal assemblage. We believe that these data can best be accounted for by accepting a causal model of geographically heterogeneous deterioration and subsequent restructuring of marine planktic habitats that took place over an extended interval of time and was ultimately driven by a synergistic combination of climatic (global cooling), oceanographic (sea level change) and tectonic factors.

scholarly journals Non-marine fish of the late Santonian Milk River Formation of Alberta, Canada – evidence from vertebrate microfossil localities

2017 ◽  
Vol 3 ◽  
Author(s):  
Don B Brinkman ◽  
Andrew G. Neuman ◽  
Julien Divay
Keyword(s):  
Marine Fish ◽  
Relative Abundance ◽  
Fish Assemblage ◽  
Global Temperature ◽  
High Abundance ◽  
Faunal Assemblage ◽  
Abundance Patterns ◽  
First Occurrence ◽  
Milk River Formation ◽  
River Fish

The diversity of fishes from the late Santonian Milk River Formation is investigated using a combined taxonomic/morphotype approach. Twenty-one taxa are present, including four elasmobranchs, seven basal actinopterygians, and of ten teleosts. The Milk River fish assemblage is more similar to assemblages from southern Utah than it is to the late Campanian assemblage of Alberta in the presence of the elasmobranch Lonchidion and a member of amiid subfamily Vidalamiinae, the relatively high abundance of the ostariophysan teleost U3/BvD, and the absence of sturgeon, Holostean A, Holostean B, and Coriops. This similarity is hypothesized to be the result of a northern shift in the distribution of these taxa during times of high global temperature, resulting in the presence of a “southern” faunal assemblage in Alberta during the late Santonian. In the relative abundance patterns of major groups of fish, the Milk River Formation assemblage is similar to late Campanian assemblages and different from those of late Maastrichtian in that amiids and lepsisoteids are of relatively low abundance. The abundance of acanthomorph teleosts in the Milk River Formation is similar to that of contemporaneous assemblages from Utah, which supports a pattern of increasing abundance of acanthomorphs from their first occurrence in non-marine vertebrate assemblages of the Western Interior in the Coniacian through to the end of the Cretaceous.

Long-Term Development of Biological Communities

1990 ◽  
Vol 5 ◽  
pp. 1-12 ◽  
Author(s):  
Robert E. Ricklefs
Keyword(s):  
Community Structure ◽  
Food Web ◽  
Relative Abundance ◽  
Functional Unit ◽  
Level Structure ◽  
Biological Communities ◽  
Abundance Patterns ◽  
Community Theory ◽  
Coexisting Species

I shall define biological community as the species comprising a temporally and spatially localized assemblage. Although members of a community may interact, I do not wish to imply that the community behaves as a functional unit or that interactions among members determine its structure. When discussing community structure in this paper, I refer exclusively to the diversity of species because of the general availability of comparative data and because most of community theory makes predictions concerning number of coexisting species. Other important community attributes, such as relative abundance patterns, trophic level structure, food web organization, resistance to and recovery from perturbation, and physical architecture, will not be considered.

scholarly journals Do similar foragers flock together? Nonbreeding foraging behavior and its impact on mixed-species flocking associations in a subtropical region

The Auk ◽  
2020 ◽  
Vol 137 (2) ◽  
Author(s):  
Harrison H Jones ◽  
Mitchell J Walters ◽  
Scott K Robinson
Keyword(s):  
Foraging Behavior ◽  
Relative Abundance ◽  
Foraging Ecology ◽  
Fine Scale ◽  
Mixed Species ◽  
Substrate Use ◽  
Nonbreeding Season ◽  
Abundance Patterns ◽  
Mixed Species Flocks ◽  
Species Flocks

Abstract Mixed-species flocks are ubiquitous in forest bird communities, yet the extent to which positive (facilitative) or negative (competitive) interactions structure these assemblages has been a subject of debate. Here, we describe the fine-scale foraging ecology and use network analysis to quantify mixed-species flocking interactions of an insectivorous bird community in hardwood forests of north-central Florida. Our goal was to determine if similarly foraging species are more (facilitation hypothesis) or less (competition hypothesis) likely to associate in flocks, and if foraging ecology can explain intraspecific abundance patterns within flocks. We quantified attack maneuvers, foraging substrate, and foraging microhabitat of all 17 common insectivorous species in these forests and characterized the composition of 92 flocks encountered. Flocking was important in our community; 14 of 17 species joined more than 5% of flocks, and 10 species had flocking propensities of over 0.80. Our results supported both hypothesized mechanisms structuring flock composition. Species had distinct, well-defined foraging niches during the nonbreeding season, but foraging niche overlap among flocking species was greater than expected by chance. Consistent with the facilitation hypothesis, we found that similarly foraging species were significantly more likely to associate in flocks, a result driven by lower association strengths in large-bodied woodpeckers. We found no evidence of assortment by foraging behavior, however, likely because foraging behavior and substrate use showed strong niche partitioning at the fine scale within our community. Intraspecific abundance patterns were significantly linked to foraging substrate use, with live leaf use correlated with high within-flock abundance and relative abundance at study sites. Species that specialized on comparatively less abundant substrates (tree trunks, epiphytes, dead leaves) joined flocks as singletons, showed lower relative abundance, and may exhibit nonbreeding territoriality. Our results highlight the importance of foraging substrate use and mixed-species flocks in structuring the nonbreeding ecology of migratory birds.

scholarly journals The collapse of the scallop Euvola ziczac (Linnaeus, 1758) (Bivalvia: Pectinidae) fishery in Brazil: changes in distribution and relative abundance after 23 years of exploitation

2004 ◽  
Vol 52 (3-4) ◽  
pp. 225-236 ◽  
Author(s):  
Paulo Ricardo Pezzuto ◽  
Carlos Alberto Borzone
Keyword(s):  
Relative Abundance ◽  
Fishery Management ◽  
Cumulative Effects ◽  
Management Model ◽  
Substantial Part ◽  
Irreversible Damage ◽  
Abundance Patterns ◽  
Stock Biomass ◽  
Main Target ◽  
Farfantepenaeus Paulensis

In Brazil, an industrial trawling fishery directed to Euvola ziczac started in 1973 and collapsed after 1980, when scallop landings reached 8,800 t. Since 1995 E. ziczac landings have not surpassed a few hundred kilograms. Based on surveys carried out in 1974-1975 and in 1995-1996, this work assesses temporal changes occurred in scallop distribution and relative abundance patterns and analyzes the current stock situation under the present management regimes applied to the local demersal trawling fishery. In the 1970's E. ziczac was concentrated in a main bed extending from southern São Paulo to northern Santa Catarina States and between 30 and 50 m depth. This pattern changed dramatically during the 1990's, when only two very small and low-density concentrations were found in the region. Cumulative effects of reducing areas and density within the remnant concentrations produced a reduction in the stock biomass of 98%. Management of the local double rig trawler fishery has always focused on its first main target, the shrimps Farfantepenaeus paulensis and F. brasiliensis. Additional measures have not been implemented, even after substantial part of the fleet has directed its effort to alternative shelf and slope resources. The collapse of the Brazilian scallop fishery provides a striking example of irreversible damage caused by uncontrolled fishing redirection allocated to other resources, demonstrating the need of changes in the Brazilian demersal fishery management model.

scholarly journals Spatiotemporal variations in aphid-parasitoid relative abundance patterns and food webs in agricultural ecosystems

Ecosphere ◽  
2015 ◽  
Vol 6 (7) ◽  
pp. art113 ◽  
Author(s):  
Thiago Oliveira Andrade ◽  
Yannick Outreman ◽  
Liliane Krespi ◽  
Manuel Plantegenest ◽  
Aude Vialatte ◽  
...  
Keyword(s):  
Food Webs ◽  
Relative Abundance ◽  
Spatiotemporal Variations ◽  
Aphid Parasitoid ◽  
Agricultural Ecosystems ◽  
Abundance Patterns

scholarly journals Relative abundance and reproductive tactics of a Loricariidae species at Saraiva Lagoon, Ilha Grande National Park, MS-PR, Brazil

2011 ◽  
Vol 11 (3) ◽  
pp. 171-178 ◽  
Author(s):  
Dayani Bailly ◽  
Valéria Flávia Batista-Silva ◽  
Milza Celi Fedatto Abelha ◽  
Elaine Antoniassi Luiz Kashiwaqui ◽  
Carlos Alexandre Fernandes ◽  
...  
Keyword(s):  
Relative Abundance ◽  
National Park ◽  
Reproductive Activity ◽  
Reproductive Period ◽  
Spatial And Temporal Variation ◽  
Oocyte Diameter ◽  
Reproductive Tactics ◽  
Abundance Patterns ◽  
Upper Paraná River Floodplain ◽  
Autumn And Winter

This study aimed to evaluate population abundance patterns and the main events in the reproductive cycle of Loricariichthys platymetopon at Saraiva Lagoon, Ilha Grande National Park, MS-PR, Brazil. Monthly samplings were conducted from October 2004 to September 2005 in three sections of the lagoon: entrance, middle and end, which resulted in the capture of 175 individuals. Spatial and temporal variation in abundance was obtained through CPUE (number of captured individuals/1000 m² of gillnets in 12 hours). The reproductive tactics considered were: duration, time and location of spawning, oocyte diameter and fecundity. The highest relative abundance was recorded in February, in the middle section of the lagoon, and the reproductive period lasted from September to February. The prevalence of females with spent ovaries and at rest in the following months indicated that reproductive activity ceased during autumn and winter. We observed that reproduction was high at the end section of the lagoon. The recorded mean oocyte diameter was 1.67 (SD ± 0.76) mm, mean absolute fecundity was 962.1 (SD ± 382.48) oocytes, and relative fecundity was 7.60 (SD ± 2.25) oocytes/g and 5.13 (SD ± 0.75) oocytes/cm. These tactics, probably are related to the settlement of L. platymetopom in Saraiva Lagoon, as well as in the different biotopes of the Upper Paraná River floodplain.

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