The Swift Fox in Rangeland and Cropland in Western Kansas: Relative Abundance, Mortality, and Body Size

2000 ◽  
Vol 45 (2) ◽  
pp. 221 ◽  
Author(s):  
Raymond S. Matlack ◽  
Philip S. Gipson ◽  
Donald W. Kaufman
Paleobiology ◽  
2008 ◽  
Vol 34 (3) ◽  
pp. 342-359 ◽  
Author(s):  
Seth Finnegan ◽  
Mary L. Droser

Major shifts in ecological dominance are one of the most conspicuous but poorly understood features of the fossil record. Here we examine one of the most prominent such shifts, the Ordovician shift from trilobite to brachiopod dominance of benthic ecosystems. Using an integrated database of high-resolution paleoecological samples and body size data, we show that while the average local richness and relative abundance of trilobites declined significantly through the Ordovician, the estimated standing biomass of trilobites, and by implication the amount of energy that they used, remained relatively invariant. This is attributable to an increase in the average body size of trilobite species in our data set, and especially to the widespread occurrence of the exceptionally large Middle-Late Ordovician trilobite genus Isotelus. Brachiopods increase in both mean body size and relative abundance throughout the Ordovician, so that estimates of brachiopod biomass and energetic use increase substantially between the Early and Late Ordovician. Although the data set includes a range of depositional environments, similar trends are observed in both shallow subtidal and deep subtidal settings. These results suggest that diversification of the Paleozoic Fauna did not come at the energetic expense of the Cambrian Fauna. The declining relative abundance of trilobites may reflect a combination of numerical dilution and the necessary energetic trade-offs between body size and abundance.


2008 ◽  
Vol 68 (2) ◽  
pp. 229-232 ◽  
Author(s):  
RR. Faria ◽  
TN. Lima

The aim of this study was to analyze: i) the spider community in vegetative and reproductive branches of Psychotria carthagenensis concerning relative abundance, guild composition and body size distribution; ii) ant abundance in diferent types of branches and iii) the spider behavior when experimentally put in contact with inflorescences covered with ants. There was no difference between vegetative and reproductive branches in relation to spider abundance, composition of guilds and body size distribution of spiders. However, there was a significant difference in ant abundance. In the behavioral experiment, 90% of the spiders were expelled from inflorescences by ants; in control treatment, 100% remained in the inflorescences. The ant density in different parts of the plant may explain the spider distribution.


1983 ◽  
Vol 61 (7) ◽  
pp. 1580-1586 ◽  
Author(s):  
Lawrence D. Harder

Ingestion of liquids by a short-tongued bee (Andrena carlini), recorded cinematographically, involved repeated protraction and retraction of the prementum and coordinated lapping by the glossa while the maxillae remained motionless. The action of the proboscis of a long-tongued bee (Bombus pennsylvanicus) differs from this in that the prementum remains stationary. Differences in proboscidial mechanics are associated with morphological differences, which together affect the ingestion rates observed for five species of each of the two types of bees. Although small bees of both morphological types ingested nectar at equivalent rates, large long-tongued bees were more efficient than short-tongued bees of similar body size. The relative abundance of large bees in long-tongued families in two faunas suggests that the comparative efficiencies of these two morphological conditions has had evolutionary consequences.


Author(s):  
Randall B. Irmis

ABSTRACTMany hypotheses have been proposed for the rise of dinosaurs, but their early diversification remains poorly understood. This paper examines the occurrences, species diversity and abundance of early dinosaurs at both regional and global scales to determine patterns of their early evolutionary history. Four main patterns are clear: (1) sauropodomorph dinosaurs became abundant during the late Norian–Rhaetian of Gondwana and Europe; (2) Triassic dinosaurs of North America have low species diversity and abundance until the beginning of the Jurassic; (3) sauropodomorphs and ornithischians are absent in the Triassic of North America; and (4) ornithischian dinosaurs maintain low species diversity, relative abundance and small body size until the Early Jurassic. No one hypothesis fully explains these data. There is no evidence for a Carnian–Norian extinction event, but sauropodomorphs did become abundant during the Norian in some assemblages. No clear connection exists between palaeoenvironment and early dinosaur diversity, but environmental stress at the Triassic–Jurassic boundary is consistent with changes in North American dinosaur assemblages. Elevated growth rates in dinosaurs are consistent with the gradual phyletic increase in body size. This study demonstrates that early dinosaur diversification was a complex process that was geographically diachronous and probably had several causes.


2007 ◽  
Vol 64 (12) ◽  
pp. 1770-1780 ◽  
Author(s):  
Joanna Lynne McGarvie Hirner ◽  
Sean P Cox

Stocking lakes with trout to enhance recreational fishing can negatively affect native aquatic species. Our objectives were (i) to compare presence, relative abundance, body size, and developmental stage of amphibians in lakes with and without rainbow trout (Oncorhynchus mykiss) in British Columbia’s southern interior, and (ii) to estimate the size of trout impact for application to amphibian conservation. Presence of long-toed salamander (Ambystoma macrodactylum), Columbia spotted frog (Rana luteiventris), and Pacific treefrog (Pseudacris regilla) was not significantly different between lake types. In contrast, western toad (Bufo boreas) larvae presence and relative abundance were significantly higher in lakes with trout. Relative abundance of salamander larvae was significantly lower in lakes with trout, but hypothesis testing did not provide consistent evidence of significantly lower abundances of spotted frog and treefrog larvae. However, estimated ratios of relative abundance (impact) indicated that larvae of the salamander and two frogs were ≥65% less abundant in lakes with trout. Salamander larvae were significantly smaller in lakes with trout. Although amphibians may currently coexist with trout in our study region, trout stocking policy in British Columbia should consider amphibian conservation because the presence of trout is associated with lower amphibian abundance and body size in individual lakes.


Paleobiology ◽  
1991 ◽  
Vol 17 (3) ◽  
pp. 231-245 ◽  
Author(s):  
John C. Barry ◽  
Michele E. Morgan ◽  
Alisa J. Winkler ◽  
Lawrence J. Flynn ◽  
Everett H. Lindsay ◽  
...  

Problems of stratigraphic completeness and poor temporal resolution make analysis of faunal change in terrestrial sequences difficult. The fluvial Neogene Siwalik formations of India and Pakistan are an exception. They contain a long vertebrate record and have good chronostratigraphic control, making it possible to assess the influence of biotic interchange on Siwalik fossil communities. In Pakistan, the interval between 18 and 7 Ma has been most intensively studied and changes in diversity and relative abundance of ruminant artiodactyls and muroid rodents are documented with temporal resolution of 200,000 years. Within this interval, diversity varies considerably, including an abrupt rise in species number between 15 and 13 Ma, followed by a decline in ruminant diversity after 12 Ma and a decline in muroid diversity in two steps at 13 and 10 Ma. Significant changes in relative abundance of taxa include an increase in bovids between 16.5 and 15 Ma, a decrease in tragulids after 9 Ma, and a very abrupt increase in murids at 12 Ma. Megacricetodontine rodents also decrease significantly at 12 Ma, and smaller declines are recorded among myocricetodontine and copemyine rodents after 16 Ma. An increase of dendromurine rodents at 15.5 Ma is also observed. There is also a trend of progressive size increase among giraffoids and bovids throughout the sequence.We have also investigated relationships between biotic interchange and diversity, body size, and relative abundance, concluding that (1) the rapid increase in ruminant and muroid diversity was largely due to immigration, whereas in situ speciation had only a secondary role; (2) during intervals of increasing diversity, resident lineages did not have higher than average rates of in situ speciation; (3) during intervals with rising diversity, greater extinction did not accompany increased immigration; (4) during intervals with falling diversity, there may have been greater extinction in recently invading lineages; and (5) change in diversity was independent of changes in relative abundance and body size.


2009 ◽  
Vol 35 (2) ◽  
pp. 182-189 ◽  
Author(s):  
Tana V. McDaniel ◽  
Pamela A. Martin ◽  
Glenn C. Barrett ◽  
Kim Hughes ◽  
Andrée D. Gendron ◽  
...  

2013 ◽  
Vol 127 (2) ◽  
pp. 131
Author(s):  
Garry E. Hornbeck ◽  
Dan Soprovich

Prairie Long-tailed Weasels (Mustela frenata longicauda) were live-trapped during fall 2005, 2006, and 2007 at Pine Coulee Reservoir and during fall 2005, 2008, and 2010 at Twin Valley Reservoir in southwestern Alberta. Our objective was to estimate the relative abundance of the Long-tailed Weasel and to estimate the relative abundance of small mammal prey. Body size and capture rates are reported for Long-tailed Weasels, and we report capture rates of small mammals. Annual capture rates for Long-tailed Weasels at Pine Coulee Reservoir were 0.44, 0.41, and 0.50 individuals per 100 corrected trap-nights (0.42, 0.38, and 0.48 individuals/100 trap-nights) in 2005, 2006, and 2007, respectively. No Long-tailed Weasels were captured at Twin Valley Reservoir. The probability of capturing zero Long-tailed Weasels at Twin Valley Reservoir was very low, assuming a true capture probability equivalent to that observed at Pine Coulee Reservoir. Deer Mice (Peromyscus maniculatus) were the most abundant small mammals captured in both project areas. Few shrews (Sorex spp.) and voles (Microtus spp.) were captured in either area.


1990 ◽  
Vol 330 (1257) ◽  
pp. 283-291 ◽  

Links between population dynamics, the relative abundance of species and the richness of animal communities are reviewed within the framework ol a simple conceptual model, based on body size and abundance. Populations of individual species occupy positions in this body size: abundance space. Problems of relative abundance and absolute species-richness revolve around a number ol simple questions, including: what determines the upper and lower bounds (maximum and minimum population densities) of species in the assemblage; what determines the overall density of points (number of species) within these bounds; and how are the vertical and horizontal partitioning rules between species decided? The answers to these, and related questions, are briefly reviewed.


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