Open Access. Powered by Scholars. Published by Universities.®

Life Sciences Commons

Open Access. Powered by Scholars. Published by Universities.®

Selected Works

Ecology and Evolutionary Biology

2012

Institution
Keyword
Publication
File Type

Articles 1 - 30 of 147

Full-Text Articles in Life Sciences

What Can We Learn From Confusing Olivella Columellaris And O. Semistriata, Two Key Species In Panamic Sandy Beach Ecosystems?, Alison Troost, Samantha Rupert, Ariel Cyrus, Frank Paladino, Benjamin Dattilo, Winfried Peters Jul 2014

What Can We Learn From Confusing Olivella Columellaris And O. Semistriata, Two Key Species In Panamic Sandy Beach Ecosystems?, Alison Troost, Samantha Rupert, Ariel Cyrus, Frank Paladino, Benjamin Dattilo, Winfried Peters

Benjamin F. Dattilo

Olivella columellaris (Sowerby 1825) and O. semistriata (Gray 1839) are suspension feeding, swash surfing snails on tropical sandy beaches of the east Pacific. While they often are the numerically dominant macrofaunal element in their habitats, their biology is poorly understood; the two species actually have been confused in all of the few publications that address their ecology. Frequent misidentifications in publications and collections contributed also to an overestimation of the geographic overlap of the two species. To provide a sound taxonomic basis for further functional, ecological, and evolutionary investigations, we evaluated the validity of diagnostic traits in wild populations and …


Buried Clay Pipe Irrigation, David A. Bainbridge Dec 2012

Buried Clay Pipe Irrigation, David A. Bainbridge

David A Bainbridge

The buried clay pipe method of irrigation is one of the most efficient systems known and is ideal for gardeners and small farmers. Buried clay pipe irrigation uses a buried, unglazed clay pipe filled with water to provide controlled irrigation to plants as the water seeps out through the clay wall at a rate that is influenced by the plant's water use. It has been used for more than one hundred years.This auto-regulation leads to very high efficiency--considerably better than drip irrigation and many times better than conventional surface irrigation. This also reduces weeds, increases yields, and can speed maturity …


The Action Component Of Recognition Systems: A Focus On The Response, Aviva E. Liebert, Philip T. Starks Dec 2012

The Action Component Of Recognition Systems: A Focus On The Response, Aviva E. Liebert, Philip T. Starks

Aviva E Liebert

The action component of recognition systems is concerned with the response of an evaluator to perceived cues, based on the dissimilarity of those cues compared with a template. Building upon the historical focus on kin recognition, we apply the framework of conspecific acceptance thresholds to recognition in a broader sense, including interactions within and between organisms, between species, and between living and nonliving things. We review examples from a variety of taxa and recognition contexts to demonstrate when a discriminatory response is expected, and how this response may be flexible depending on the costs and benefits of recognition errors and …


Genetics, Behavior And Ecology Of A Paper Wasp Invasion: Polistes Dominulus In North America, Aviva Liebert Dec 2012

Genetics, Behavior And Ecology Of A Paper Wasp Invasion: Polistes Dominulus In North America, Aviva Liebert

Aviva E Liebert

Studies of social insect invasions to date have focused primarily on highly eusocial insects such as ants and yellowjacket wasps. Yet insect societies without fixed, morphological caste systems may be particularly good invaders due to their behavioral flexibility, as demonstrated by the recent invasion of the European paper wasp Polistes dominulus into North America. Here we provide a review of this ongoing invasion in terms of (1) population genetic variation in P. dominulus, and (2) comparative behavior and ecology of P. dominulus vs. the native P. fuscatus. We present new genetic evidence supporting the occurrence of multiple independent introductions of …


Evolution Of Repetitive Proteins: Spider Silks From Nephila Clavipes (Tetragnathidae) And Araneus Bicentenarius (Araneidae), Richard D. Beckwitt, Steven Arcidiacono, Robert Stote Dec 2012

Evolution Of Repetitive Proteins: Spider Silks From Nephila Clavipes (Tetragnathidae) And Araneus Bicentenarius (Araneidae), Richard D. Beckwitt, Steven Arcidiacono, Robert Stote

Richard D Beckwitt

Spider silks are highly repetitive proteins, characterized by regions of polyalanine and glycine-rich repeating units. We have obtained two variants of the Spidroin 1 (NCF-1) silk gene sequence from Nephila clavipes. One sequence (1726 bp) was from a cloned cDNA, and the other (1951 bp) was from PCR of genomic DNA. When these sequences are compared with each other and the previously published Spidroin 1 sequence, there are differences due to sequence rearrangements, as well as single base substitutions. These variations are similar to those that have been reported from other highly repetitive genes, and probably represent the results …


Interactions Between Pieris Oleracea And Pieris Rapae (Lepidoptera: Pieridae) Butterflies, And The Biological Control Agents Cotesia Glomerata And Cotesia Rubecula (Hymenoptera: Braconidae)., Megan V. Herlihy Dec 2012

Interactions Between Pieris Oleracea And Pieris Rapae (Lepidoptera: Pieridae) Butterflies, And The Biological Control Agents Cotesia Glomerata And Cotesia Rubecula (Hymenoptera: Braconidae)., Megan V. Herlihy

Megan V Herlihy

Pieris oleracea, formerly Pieris napi, was once a widespread pierid butterfly in New England until the introduction of a biological control agent, Cotesia glomerata. It has been suggested that C. glomerata is responsible for the range reduction of P. oleracea. There are been several introductions of a second more specialized biological control agent, Cotesia rubecula, to the United States since the 1960’s. My first goal was to determine the current distribution and status of P. rapae parasitoids and the effectiveness of C. rubecula as a biological control agent since its release. The findings of a survey I conducted of the …


Effects Of Elevated Carbon Dioxide And Increased Temperature On Methane And Nitrous Oxide Fluxes: Evidence From Field Experiments, Feike A. Dijlstra, Stephen A. Prior, G. Brett Renion, H. Allen Torbert, Hanqin Tian, Chaoqun (Crystal) Lu, Rodney T. Venterea Dec 2012

Effects Of Elevated Carbon Dioxide And Increased Temperature On Methane And Nitrous Oxide Fluxes: Evidence From Field Experiments, Feike A. Dijlstra, Stephen A. Prior, G. Brett Renion, H. Allen Torbert, Hanqin Tian, Chaoqun (Crystal) Lu, Rodney T. Venterea

Chaoqun (Crystal) Lu

Climate change could alter terrestrial ecosystems, which are important sources and sinks of the potent green-house gases (GHGs) nitrous oxide (N2O) and methane (CH4), in ways that either stimulate or decrease the magnitude and duration of global warming. Using manipulative field experiments, we assessed how N2O and CH4 soil fluxes responded to a rise in atmospheric carbon dioxide (CO2) concentration and to increased air temperature. Nitrous oxide and CH4 responses varied greatly among studied ecosystems. Elevated CO2 often stimulated N2O emissions in fertilized systems and CH4 emissions in wetlands, peatlands, and rice paddy fields; both effects were stronger in clayey …


Pocket Guide To Sagebrush, Leila M. Shultz Dec 2012

Pocket Guide To Sagebrush, Leila M. Shultz

Leila M Shultz

No abstract provided.


The Role Of Olfactory Cues In The Sequential Radiation Of A Gall-Boring Beetle, Mordellistena Convicta, Bradley Rhodes, Catherine Blair, Mizuki Takahashi, Warren Abrahamson Nov 2012

The Role Of Olfactory Cues In The Sequential Radiation Of A Gall-Boring Beetle, Mordellistena Convicta, Bradley Rhodes, Catherine Blair, Mizuki Takahashi, Warren Abrahamson

Warren G. Abrahamson, II

1. Herbivorous insects often have close associations with specific host plants, and their preferences for mating and ovipositing on a specific host-plant species can reproductively isolate populations, facilitating ecological speciation. Volatile emissions from host plants can play a major role in assisting herbivores to locate their natal host plants and thus facilitate assortative mating and host-specific oviposition. 2. The present study investigated the role of host-plant volatiles in host fidelity and oviposition preference of the gall-boring, inquiline beetle, Mordellistena convicta, using Y-tube olfactometers. Previous studies suggest that the gall-boring beetle is undergoing sequential host-associated divergence by utilizing the resources that …


Deglaciation Explains Bat Extinction In The Caribbean, Liliana M. Davalos, Amy L. Russell Nov 2012

Deglaciation Explains Bat Extinction In The Caribbean, Liliana M. Davalos, Amy L. Russell

Amy L. Russell

Ecological factors such as changing climate on land and interspecific competition have been debated as possible causes of postglacial Caribbean extinction. These hypotheses, however, have not been tested against a null model of climate-driven postglacial area loss. Here, we use a new Quaternary mammal database and deep-sea bathymetry to estimate species–area relationships (SARs) at present and during the Last Glacial Maximum (LGM) for bats of the Caribbean, and to model species loss as a function of area loss from rising sea level. Island area was a significant predictor of species richness in the Bahamas, Greater Antilles, and Lesser Antilles at …


Ultraviolet Radiation Influences Perch Selection By A Neotropical Poison-Dart Frog, Lee Kats, Gary M. Bucciarelli, David E. Schlais, Andrew R. Blaustein, Barbara A. Han Nov 2012

Ultraviolet Radiation Influences Perch Selection By A Neotropical Poison-Dart Frog, Lee Kats, Gary M. Bucciarelli, David E. Schlais, Andrew R. Blaustein, Barbara A. Han

Lee Kats

Ambient ultraviolet-B radiation can harm amphibian eggs, larvae and adults. However, some amphibians avoid UV-B radiation when given the opportunity. The strawberry poison dart frog, Oophaga pumilio, is diurnal and males vocalize throughout the day in light gaps under forest canopies that expose them to solar radiation. Previous studies have demonstrated that males calling from high perches are more successful at mating than those at lower perches. We investigated whether frogs at higher perches receive more ultraviolet-B than those calling from lower perches. We also investigated whether frogs on perches receiving relatively low ultraviolet-B levels maintained their positions for longer …


Pre-Settlement History May Obscure The Effect Of Forest Fragmentation On Genetic Variation In Eastern Red-Backed Salamanders, Mark Jordan, Douglas Morris, Scott Gibson Nov 2012

Pre-Settlement History May Obscure The Effect Of Forest Fragmentation On Genetic Variation In Eastern Red-Backed Salamanders, Mark Jordan, Douglas Morris, Scott Gibson

Mark A. Jordan

No abstract provided.


The Effects Of Water And Habitat Quality On Amphibian Assemblages In Two Midwest Watersheds, Abel Castaneda, Mark Jordan Nov 2012

The Effects Of Water And Habitat Quality On Amphibian Assemblages In Two Midwest Watersheds, Abel Castaneda, Mark Jordan

Mark A. Jordan

No abstract provided.


Patterns Of Life History And Habitat Use Of An Important Recreational Fishery Species, Spotfin Croaker, And Their Potential Fishery Implications, Jonathan Williams, Jeremy Claisse, Daniel Pondella, Lea Medeiros, Charles Valle, Michael Shane Nov 2012

Patterns Of Life History And Habitat Use Of An Important Recreational Fishery Species, Spotfin Croaker, And Their Potential Fishery Implications, Jonathan Williams, Jeremy Claisse, Daniel Pondella, Lea Medeiros, Charles Valle, Michael Shane

Daniel Pondella

Spotfin croakers Roncador stearnsii, a prized recreational catch, were collected throughout the Southern California Bight, primarily as bycatch from a long-term, scientific gill-net collection effort. The maximum otolith-based age in the present study was 24 years—14 years greater than in a previous scale-based aging study. Multiple models were used to estimate mean length at age, including models that utilize larvae as well as juveniles and adults, and the model selection results suggest sexual dimorphism in growth patterns. The juvenile and adult catch per unit effort reflected a clear pattern of habitat selectivity, with fish strongly preferring soft-bottom habitats. Catches …


El Niño Periods Increase Growth Of Juvenile White Seabass (Atractoscion Nobilis) In The Southern California Bight, Jonathan Williams, Larry Allen, Mark Steele, Daniel Pondella Nov 2012

El Niño Periods Increase Growth Of Juvenile White Seabass (Atractoscion Nobilis) In The Southern California Bight, Jonathan Williams, Larry Allen, Mark Steele, Daniel Pondella

Daniel Pondella

Studies of the impact of El Niño periods on marine species have usually focused on negative, highly visible eVects, e.g., decreasing growth rates or increasing mortality due to a decline in primary productivity in typically nutrient rich upwelling zones; but positive effects related to elevated water temperature are also known. This study examined how the growth rate of juvenile white seabass, Atractoscion nobilis, responded to changes in ocean temperature in an El Niño period (1997–1998) in the northern portion of the Southern California Bight, USA. Growth rates of juvenile white seabass during their first 4 years of life were …


Life History, Ecology, And Long-Term Demographics Of Queenfish, Eric Miller, Jonathan Williams, Daniel Pondella, Kevin Herbinson Nov 2012

Life History, Ecology, And Long-Term Demographics Of Queenfish, Eric Miller, Jonathan Williams, Daniel Pondella, Kevin Herbinson

Daniel Pondella

Queenfish Seriphus politus were collected at coastal power plants from San Clemente to Ventura, California. Power functions best described relations between otolith length, width, or weight and either standard length (SL) or total body weight. The length–weight relationship was described by the following equation: weight 1⁄4 10􏰀5 3 SL3.09. Individuals were aged to 12 years by using sagittal otolith sections. Females grew at a significantly faster rate than males. Both sexes reached 50% maturity by 100 mm SL, or shortly after age 1. The total annual instantaneous mortality coefficient was estimated at 0.42. Catalina Harbor (on the windward side of …


New Record Of Pacific Sierra (Scomberomorus Sierra) With Notes On Previous California Records, Jonathan P. Williams, Daniel J. Pondella Ii, Brent M. Haggin, Larry G. Allen Nov 2012

New Record Of Pacific Sierra (Scomberomorus Sierra) With Notes On Previous California Records, Jonathan P. Williams, Daniel J. Pondella Ii, Brent M. Haggin, Larry G. Allen

Daniel Pondella

On 22 October 2006, a Pacific sierra (Scomberomorus sierra) was caught by gillnet near Mother’s Beach, Marina del Rey, Los Angeles County, California (33º58’50"N, 118º27’25"W) during sampling for juvenile white seabass (Atractoscion nobilis). This catch represents the northernmost record of Pacific sierra, and one of several specimens known from California.


Catalogue Of Type Material In The Entomological Collection Of The University Of La Laguna (Canary Islands). I – Arachnida, Ana Reboleira, Antonio Pérez, Nuria Macías-Hernandez, Heriberto López, S. De La Cruz, Pedro Oromí Oct 2012

Catalogue Of Type Material In The Entomological Collection Of The University Of La Laguna (Canary Islands). I – Arachnida, Ana Reboleira, Antonio Pérez, Nuria Macías-Hernandez, Heriberto López, S. De La Cruz, Pedro Oromí

Ana Sofia P.S. Reboleira

A catalogue of arachnid type specimens of the collection kept at the Department of Animal Biology, University of La Laguna (Spain) is presented. It harbours type material of 104 species belonging to 23 families of arachnids, represented by 21 holotypes and 164 paratypes for 23 species of pseudoscorpions, and 49 holotypes, 218 paratypes and 3 syntypes for 81 species of spiders. This collection is using the criteria and standards of the Global Biodiversity Information Facility (GBIF) for cataloguing and computerization of the specimens. Type specimens were checked with the original descriptions, and relevant additional information from original labels not included …


Lusoblothrus, A New Syarinid Pseudoscorpion Genus (Arachnida) From Portugal, Occupying An Isolated Position Within The Holarctic Fauna, Ana Reboleira, Juan Zaragoza, Fernando Gonçalves, Pedro Oromí Oct 2012

Lusoblothrus, A New Syarinid Pseudoscorpion Genus (Arachnida) From Portugal, Occupying An Isolated Position Within The Holarctic Fauna, Ana Reboleira, Juan Zaragoza, Fernando Gonçalves, Pedro Oromí

Ana Sofia P.S. Reboleira

The new pseudoscorpion genus Lusoblothrus of the family Syarinidae is described from a cave in the Algarve region, southern Portugal, to accommodate L. aenigmaticus sp. nov., whose morphological affinities within the Holarctic syarinid fauna are not clear and resembles the Gondwanan genera. This discovery emphasizes the relevance of the Algarve region as a hotspot for relictual hypogean fauna within the Iberian Peninsula.


Shrews, Rats, And A Polecat In "The Pardoner's Tale", Sandy Feinstein, Neal Woodman Oct 2012

Shrews, Rats, And A Polecat In "The Pardoner's Tale", Sandy Feinstein, Neal Woodman

Neal Woodman

No abstract provided.


Euscorpius Sicanus (Scorpiones: Euscorpiidae) From Tunisia: Dna Barcoding Confirms Ancient Disjunctions Across The Mediterranean Sea, Matthew R. Graham, Pavel Stoev, Nesrine Akkari, Gergin Blagoev, Victor Fet Oct 2012

Euscorpius Sicanus (Scorpiones: Euscorpiidae) From Tunisia: Dna Barcoding Confirms Ancient Disjunctions Across The Mediterranean Sea, Matthew R. Graham, Pavel Stoev, Nesrine Akkari, Gergin Blagoev, Victor Fet

Victor Fet

We used a DNA barcoding marker (mitochondrial cox1) to investigate the controversial natural occurrence of Euscorpius sicanus (C.L. Koch) in North Africa. We tested this hypothesis by comparing a sample collected from a mountain in Tunisia to disjunct populations in Sardinia, Malta, and Greece. Using these samples, and a few additional Euscorpius spp. from southern Europe as outgroups, we reconstructed the maternal phylogeny. We then used a molecular clock to place the phylogeny in a temporal context. The Tunisian sample grouped closest to a specimen from Sardinia, with both being more distantly related to E. sicanus from Malta, which is …


Comparison Of Phenolic Compounds And Antioxidant Capacities Of Traditional Sorghum Beers With Other Alcoholic Beverages, Fatouma Abdoul-Latif, Romaric G. Bayili, Louis C. Obame, Mamoudou H. Dicko Prof. Oct 2012

Comparison Of Phenolic Compounds And Antioxidant Capacities Of Traditional Sorghum Beers With Other Alcoholic Beverages, Fatouma Abdoul-Latif, Romaric G. Bayili, Louis C. Obame, Mamoudou H. Dicko Prof.

Pr. Mamoudou H. DICKO, PhD

Thirty samples of sorghum beers “dolo” were selected from traditionally fermented household manufacturers from Burkina Faso. Dolo samples were screened for their total phenolic content, proanthocyanidins and putative antioxidant capacities, and were compared with industrial beers and wines. Total phenols were measured using the Folin-Ciocalteu method. Proanthocyanidins content were determined by the method of HCl-butanol hydrolysis. Antioxidant activities were evaluated both with 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay and by the trolox equivalent antioxidant capacity (TEAC) using 2,2’-azinobis(3-ethyl-benzothiazoline-6-sulfonic acid radical) (ABTS•+). The average contents of total phenols and proanthocyanidins were 506 μg GAE/ml of dolo and 45 μg APE/ml of dolo, respectively. An …


Evidence That Glucose Is The Major Transferred Metabolite In Dinoflagellate–Cnidarian Symbiosis, Matthew S. Burriesci, Ted K. Raab, John R. Pringle Oct 2012

Evidence That Glucose Is The Major Transferred Metabolite In Dinoflagellate–Cnidarian Symbiosis, Matthew S. Burriesci, Ted K. Raab, John R. Pringle

Ted K. Raab

Reef-building corals and many other cnidarians are symbiotic with dinoflagellates of the genus Symbiodinium. It has long been known that the endosymbiotic algae transfer much of their photosynthetically fixed carbon to the host and that this can provide much of the hostʼs total energy. However, it has remained unclear which metabolite(s) are directly translocated from the algae into the host tissue. We reexamined this question in the small sea anemone Aiptasia using labeling of intact animals in the light with 13C-bicarbonate, rapid homogenization and separation of animal and algal fractions, and analysis of metabolite labeling by gas chromatography-mass spectrometry. We …


Libraries At The University Of Massachusetts Amherst: Seeking An International Perspective, Maxine G. Schmidt Oct 2012

Libraries At The University Of Massachusetts Amherst: Seeking An International Perspective, Maxine G. Schmidt

Maxine G Schmidt

Presentation delivered to librarians in China, Japan and South Korea as part of my sabbatical research on the use of libraries by Asian students in their home countries.


A Regional Comparison Of Water Use Efficiency For Miscanthus, Switchgrass And Maize, Andy Vanloocke, Tracy E. Twine, Marcelo Zeri, Carl J. Bernacchi Sep 2012

A Regional Comparison Of Water Use Efficiency For Miscanthus, Switchgrass And Maize, Andy Vanloocke, Tracy E. Twine, Marcelo Zeri, Carl J. Bernacchi

Andy VanLoocke

The production of cellulosic feedstocks for renewable fuels will increase over the coming decades. However, it is uncertain which feedstocks will be best suited for bioenergy production. A key factor dictating feedstock selection for a given region is water use efficiency (WUE), the trade-off between evapotranspiration (ET) and carbon uptake or productivity. Using an ecosystem model, two of the top candidate cellulosic feedstocks, Miscanthus × giganteus (miscanthus) and Panicum virgatum (switchgrass) were compared to Zea mays L. (maize), the existing dominant bioenergy feedstock, with 0 and 25% residue removal for the Midwest US. We determined productivity in three ways: harvested …


Natural Disturbances And The Physiognomy Of Pine Savannas : A Phenomenological Model, Frank S. Gilliam, William J. Platt, Robert K. Peet Sep 2012

Natural Disturbances And The Physiognomy Of Pine Savannas : A Phenomenological Model, Frank S. Gilliam, William J. Platt, Robert K. Peet

Frank S. Gilliam

Abstract. Question: The decline of the Pinus palustris ecosystems has resulted from anthropogenic influences, such as conversion to pine plantation forestry, agriculture and land development, all of which are closely related to increases in human populations. Other effects, however, have arisen from alterations in disturbance regimes that maintain the structure and function of these ecosystems. How have alterations of the disturbance regime altered the physiognomy of ‘old-growth’ stands, and what are the implications for ecosystem conservation and restoration? Methods: In contrast to models that emphasize close interactions among the vertically complex strata, we develop a conceptual phenomenological model for the …


Global Assessment Of Nitrogen Deposition Effects On Terrestrial Plant Diversity : A Synthesis, R. Bobbink, K. Hicks, J. Galloway, T. Spranger, R. Alkemade, M. Ashmore, M. Bustamante, S. Cinderby, E. Davidson, F. Dentener, B. Emmett, J. W. Erisman, M. Fenn, Frank S. Gilliam, A. Nordin, L. Pardo, W. Devries Sep 2012

Global Assessment Of Nitrogen Deposition Effects On Terrestrial Plant Diversity : A Synthesis, R. Bobbink, K. Hicks, J. Galloway, T. Spranger, R. Alkemade, M. Ashmore, M. Bustamante, S. Cinderby, E. Davidson, F. Dentener, B. Emmett, J. W. Erisman, M. Fenn, Frank S. Gilliam, A. Nordin, L. Pardo, W. Devries

Frank S. Gilliam

Atmospheric nitrogen (N) deposition is a recognized threat to plant diversity in temperate and northern parts of Europe and North America. This paper assesses evidence from field experiments for N deposition effects and thresholds for terrestrial plant diversity protection across a latitudinal range of main categories of ecosystems, from arctic and boreal systems to tropical forests. Current thinking on the mechanisms of N deposition effects on plant diversity, the global distribution of G200 ecoregions, and current and future (2030) estimates of atmospheric N-deposition rates are then used to identify the risks to plant diversity in all major ecosystem types now …


Preliminary Report On The Osteology And Relationships Of A New Aberrant Cryptocleidoid Plesiosaur From The Sundance Formation, Wyoming, F. Robin O’Keefe, William Wahl Jr. Sep 2012

Preliminary Report On The Osteology And Relationships Of A New Aberrant Cryptocleidoid Plesiosaur From The Sundance Formation, Wyoming, F. Robin O’Keefe, William Wahl Jr.

F. Robin O’Keefe

The cryptocleidoid plesiosaur Tatenectes laramiensis, new genus, is described from the Redwater Shale Member of the Sundance Formation, Narrona County, Wyoming. The holotype of this species was a partial skeleton that has since been lost. A neotype is designated that preserves the same elements present in the holotype. A second specimen is referred to the taxon, and this specimen includes cranial material. The preserved cranial elements are the left squamosal, a partial right frontal, several isolated teeth, the parasphenoid, and large portions of the left and right pterygoids. The skull shares many traits with that of Kimmerosaurus, a cryptocleidoid plesiosaur …


Compilation, Calibration, And Synthesis Of Faunal And Floral Radiocarbon Dates, Rancho La Brea, California, F. O’Keefe, Elizabeth Fet, John Harris Sep 2012

Compilation, Calibration, And Synthesis Of Faunal And Floral Radiocarbon Dates, Rancho La Brea, California, F. O’Keefe, Elizabeth Fet, John Harris

F. Robin O’Keefe

This paper presents a compilation and synthesis of calibrated radiocarbon dates for the Rancho La Brea tar pits, Los Angeles, California. A literature survey yielded 188 dates, and 21 additional dates are presented here for the first time. These range in age from 185 to 50,000 radiocarbon years. Dating of Rancho La Brea fossils has been uneven; only from Pits 91 and 2051 have more than 30 dates been obtained. The depositional history of well-sampled pits was complex, with one or more episodes of major accumulation interspersed with lower background levels of entrapment. The most significant quantifiable source of error …


Conservation And Restoration Of The Pinus Palustris Ecosystem, Frank S. Gilliam, William J. Platt Sep 2012

Conservation And Restoration Of The Pinus Palustris Ecosystem, Frank S. Gilliam, William J. Platt

Frank S. Gilliam

The well-documented decline of the Pinus palustris ecosystem has resulted from several anthropogenic influences, such as forest clearing (e.g. pine plantation forestry, agriculture) and urban development, both of which are closely related to increases in human populations. Other impacts have arisen from alterations in disturbance regimes responsible for maintaining the structure and function of these ecosystems. Restoration and management of degraded pine savanna ecosystems is critical. Identification of ecological processes that determine the structure and function of the intact system are important because successful restoration efforts should be based on sound scientific understanding. In this paper, we introduce this special …