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Full-Text Articles in Life Sciences

Geographic Segregation And Evidence Of Density-Dependent Changes In Sex Ratios In An Abundant Colonial Waterbird, Brian S. Dorr, Katie C. Hanson-Dorr, Travis L. Devault, Alban Guillaumet, Scott C. Barras Dec 2014

Geographic Segregation And Evidence Of Density-Dependent Changes In Sex Ratios In An Abundant Colonial Waterbird, Brian S. Dorr, Katie C. Hanson-Dorr, Travis L. Devault, Alban Guillaumet, Scott C. Barras

Brian S Dorr

Demographic information, such as geographic segregation of sexes and sex ratio data, is needed to develop, model and evaluate conservation and management strategies for wildlife. A variety of physiological, behavioral and environmental factors can influence segregation of sexes and sex ratios, many of which originate with density- dependent processes. Departure from 50:50 sex ratios of double-crested cormorants (Phalacrocorax auritus) collected during control efforts in breeding and wintering areas across their eastern range of the USA were evaluated using using a Z-test as well as Stouffer’s weighted Z-tests. In addition, a specifically-designed randomization test was used to evaluate density-dependent effects on …


The Reproduction And Ecology Of Hypericum Edisonianum: An Endangered Florida Endemic, Warren G. Abrahamson Ii, Sam P. Vander Kloet Aug 2014

The Reproduction And Ecology Of Hypericum Edisonianum: An Endangered Florida Endemic, Warren G. Abrahamson Ii, Sam P. Vander Kloet

Warren G. Abrahamson, II

The reproduction and ecology of the narrow endemic and Florida endangered shrub Hypericum edisonianum (Edison’s St. John's Wort) was investigated through field and greenhouse studies. Hypericum edisonianum exhibits a number of traits common to rare and geographically limited plant species including heavy reliance on clonal propagation to maintain local stands; passive seed dispersal resulting in a near-parent seed shadow; limited numbers of genetically unique individuals in its isolated seasonal-pond habitat; and likely self-incompatibility. In the field study, most flowers were produced by a small subset of the monitored ramets. Indeed, three ramets belonging to a single genetic individual accounted for …


A New Species Of Small-Eared Shrew (Mammalia, Eulipotyphla, Cryptotis) From The Lacandona Rain Forest, Mexico, Lázaro Guevara, Victor Sánchez-Cordero, Livia León-Paniagua, Neal Woodman Aug 2014

A New Species Of Small-Eared Shrew (Mammalia, Eulipotyphla, Cryptotis) From The Lacandona Rain Forest, Mexico, Lázaro Guevara, Victor Sánchez-Cordero, Livia León-Paniagua, Neal Woodman

Neal Woodman

The diversity and distribution of mammals in the American tropics remain incompletely known. We describe a new species of small-eared shrew (Soricidae, Cryptotis) from the Lacandona rain forest, Chiapas, southern Mexico. The new species is distinguished from other species of Cryptotis on the basis of a unique combination of pelage coloration, size, dental, cranial, postcranial, and external characters, and genetic distances. It appears most closely related to species in the Cryptotis nigrescens species group, which occurs from southern Mexico to montane regions of Colombia. This discovery is particularly remarkable because the new species is from a lowelevation habitat (approximately 90 …


Effects Of Prey Abundance On Breeding Season Diet Of Northern Goshawks (Accipiter Gentilis) Within An Unusual Prey Landscape, Robert A. Miller, Jay D. Carlisle, Marc J. Bechard Mar 2014

Effects Of Prey Abundance On Breeding Season Diet Of Northern Goshawks (Accipiter Gentilis) Within An Unusual Prey Landscape, Robert A. Miller, Jay D. Carlisle, Marc J. Bechard

Robert Miller

A critical element of diet analysis is species adaptability to alternative prey sources. The breeding season diet of Northern Goshawks (Accipiter gentilis) includes both mammalian and avian species, varies geographically, and is often dependent upon tree squirrels of the genera Sciurus and Tamiasciurus>/i>. We studied alternative prey sources of Northern Goshawks in the South Hills of south-central Idaho, an area where tree squirrels are naturally absent and other prey frequently important in the diet of goshawks, such as smaller corvids, are uncommon. We quantified the diet of goshawks using nest cameras and surveyed abundance of prey using line …


Avian Influenza Virus Prevalence In Migratory Waterfowl In The United States, 2007-2009, Scott R. Groepper Mr., Thomas Deliberto, Mark Vrtiska, Kerri Pedersen, Seth Swafford, Scott Hyngstrom Jan 2014

Avian Influenza Virus Prevalence In Migratory Waterfowl In The United States, 2007-2009, Scott R. Groepper Mr., Thomas Deliberto, Mark Vrtiska, Kerri Pedersen, Seth Swafford, Scott Hyngstrom

Scott R Groepper

SUMMARY. We analyzed 155,535 samples collected for surveillance of avian influenza viruses (AIVs), in the United States from 2007 to 2009, from migratory waterfowl (ducks, geese, and swans). The goal was to elucidate patterns of prevalence by flyway and functional groups to determine targets for future surveillance. Apparent prevalence of AIV was highest in the Pacific Flyway in 2007–2008 (14.2% and 14.1%, respectively), in the Mississippi Flyway in 2009 (16.8%), and lowest each year in the Atlantic Flyway (range, 7.3%–8.9%). Dabbling ducks had higher apparent prevalence of AIV (12.8%–18.8%) than diving ducks (3.9%–6.0%) or geese and swans (3.6%–3.9%). We observed …


Effects Of Disturbance And Climate Change On Ecosystem Performance In The Yukon River Basin Boreal Forest, Bruce K. Wylie, Matthew Rigge, Brian Brisco, Kevin Murnaghan, Jennifer A. Rover Jan 2014

Effects Of Disturbance And Climate Change On Ecosystem Performance In The Yukon River Basin Boreal Forest, Bruce K. Wylie, Matthew Rigge, Brian Brisco, Kevin Murnaghan, Jennifer A. Rover

Bruce K. Wylie

A warming climate influences boreal forest productivity, dynamics, and disturbance regimes. We used ecosystem models and 250 m satellite Normalized Difference Vegetation Index (NDVI) data averaged over the growing season (GSN) to model current, and estimate future, ecosystem performance. We modeled Expected Ecosystem Performance (EEP), or anticipated productivity, in undisturbed stands over the 2000–2008 period from a variety of abiotic data sources, using a rule-based piecewise regression tree. The EEP model was applied to a future climate ensemble A1B projection to quantify expected changes to mature boreal forest performance. Ecosystem Performance Anomalies (EPA), were identified as the residuals of the …


Arbuscular Mycorrhizal Symbiosis And Ecosystem Processes: Prospects For Future Research In Tropical Soils, Geofrey Soka, Mark Ritchie Jan 2014

Arbuscular Mycorrhizal Symbiosis And Ecosystem Processes: Prospects For Future Research In Tropical Soils, Geofrey Soka, Mark Ritchie

Geofrey Soka

No abstract provided.


Species Distribution Modelling Using Bioclimatic Variables To Determine The Impacts Of A Changing Climate On The Western Ringtail Possum (Pseudocheirus Occidentals; Pseudocheiridae), Shaun Molloy, Robert Davis, Eddie Van Etten Dec 2013

Species Distribution Modelling Using Bioclimatic Variables To Determine The Impacts Of A Changing Climate On The Western Ringtail Possum (Pseudocheirus Occidentals; Pseudocheiridae), Shaun Molloy, Robert Davis, Eddie Van Etten

Shaun W Molloy Dr

The ngwayir (western ringtail possum Pseudocheirus occidentalis) is an arboreal species endemic to south-western Australia. The range and population of this species have been significantly reduced through multiple anthropogenic impacts. Classified as vulnerable, the ngwayir is highly susceptible to extremes of temperature and reduced water intake. Ngwayir distribution was determined using three different species distribution models using ngwayir presence records related to a set of 19 bioclimatic variables derived fromhistorical climate data, overlaid with 2050 climate change scenarios.MaxEnt was used to identify core habitat and demonstrate how this habitat may be impacted. A supplementary modelling exercise was also conducted to …


Insect Visitation Of Peduncular And Petiolar Extrafloral Nectar Glands On Castor Bean (Ricinus Communis L.) Plants In Southern California, Victor D. Carmona Dec 2013

Insect Visitation Of Peduncular And Petiolar Extrafloral Nectar Glands On Castor Bean (Ricinus Communis L.) Plants In Southern California, Victor D. Carmona

Victor D. Carmona-Galindo

Castor bean (Ricinus communis L.) is a myrmecophytic plant species with specialized extrafloral nectar (EFN) glands that serve to attract predatory insects, which in return defend plant-tissues against herbivores. The EFN glands on castor bean plants are located along the leaf petioles as well as on the peduncles of its imperfect (unisexual) flowers. This field-project evaluates the richness, diversity, and species assemblage of insects visiting EFN glands located on (female and male) flower peduncles and leaf petioles on castor bean plants growing in a Southern California coastal landscape. We detected that EFN glands on female-flower peduncles were visited by an …


Can They Dig It? Functional Morphology And Degrees Of Semifossoriality Among Some American Shrews (Mammalia, Soricidae)., Neal Woodman, Sarah A. Gaffney Dec 2013

Can They Dig It? Functional Morphology And Degrees Of Semifossoriality Among Some American Shrews (Mammalia, Soricidae)., Neal Woodman, Sarah A. Gaffney

Neal Woodman

Small-eared shrews (Mammalia: Soricidae: Cryptotis), exhibit modifications of the forelimb skeleton that have been interpreted as adaptations for semifossoriality. Most species inhabit remote regions, however, and their locomotory and foraging behaviors remain mostly speculative. To better understand the morphological modifications in the absence of direct observations, we quantified variation in these species by measuring 151 individuals representing 18 species and populations of Cryptotis and two species of moles (Talpidae) for comparison. From our measurements, we calculated 22 indices, most of which have been used previously to characterize substrate use among rodents and other taxa. We analyzed the indices using 1) …