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Full-Text Articles in Life Sciences

Recent Decline Of Lowland Populations Of The Western Gray Squirrel In The Los Angeles Area Of Southern California, Daniel S. Cooper, Alan Muchlinski Jul 2105

Recent Decline Of Lowland Populations Of The Western Gray Squirrel In The Los Angeles Area Of Southern California, Daniel S. Cooper, Alan Muchlinski

Bulletin of the Southern California Academy of Sciences

We provide an overview of the distribution of lowland and otherwise isolated populations of the western gray squirrel (Sciurus griseus) in the Los Angeles area of southern California, an area that has experienced a recent and ongoing invasion by the non-native eastern fox squirrel (Sciurus niger), an urban-adapted species introduced a century ago. Away from its strongholds in the western Santa Monica Mountains, San Gabriel Mountains, and Santa Ana Mountains, the western gray squirrel is resident locally in both the Santa Susana and the Verdugo Mountains, in Griffith Park, in low hills at the eastern periphery of the San Gabriel ...


Range Expansion Or Range Shift? Population Genetics And Historic Range Data Analyses Of The Predatory Benthic Sea Slug Phidiana Hiltoni (Mollusca, Gastropoda, Nudibranchia), Clara Jo King, Ryan Ellingson, Jeffrey H. R. Goddard, Rebecca F. Johnson, Angel A. Valdes Jan 2019

Range Expansion Or Range Shift? Population Genetics And Historic Range Data Analyses Of The Predatory Benthic Sea Slug Phidiana Hiltoni (Mollusca, Gastropoda, Nudibranchia), Clara Jo King, Ryan Ellingson, Jeffrey H. R. Goddard, Rebecca F. Johnson, Angel A. Valdes

Bulletin of the Southern California Academy of Sciences

Phidiana hiltoni is a conspicuous nudibranch sea slug native to the northeastern Pacific Ocean. Over the past thirty years the range of P. hiltoni has expanded about 200 km northward, but the mechanism that facilitated this expansion is poorly understood. In this study, we use mtDNA and microsatellite data to investigate the population structure of P. hiltoni in its historical range as well as in recently colonized localities. Microsatellite analyses reveal little to no genetic structure and thus high gene flow throughout the range of P. hiltoni. This is consistent with mtDNA analysis results, which revealed shared haplotypes between Southern ...


Additional Information On A Nonnative Whiptail Population (Aspidoscelis Flagellicauda/Sonorae Complex) In Suburban Orange County, California, Richard A. Erickson, Weston G. Burt Jan 2019

Additional Information On A Nonnative Whiptail Population (Aspidoscelis Flagellicauda/Sonorae Complex) In Suburban Orange County, California, Richard A. Erickson, Weston G. Burt

Bulletin of the Southern California Academy of Sciences

A nonnative population of all-female spotted whiptails from the Asidoscelis flagellicauda/sonorae complex was reported from suburban Irvine, Orange County in 2015 and 2016. We report additional suburban observations dating back to 2010 from Laguna Woods and extending the range south ~6 km southwest to Aliso Viejo. We hope that this and other exotic reptile species will remain restricted to highly altered urban environments and not threaten native species in natural habitats.


An Ecological Niche Model To Predict Range Expansion Of The Eastern Gray Squirrel In California, Carly M. Creley, Alan Muchlinski, Fraser Shilling Jan 2019

An Ecological Niche Model To Predict Range Expansion Of The Eastern Gray Squirrel In California, Carly M. Creley, Alan Muchlinski, Fraser Shilling

Bulletin of the Southern California Academy of Sciences

The eastern gray squirrel, Sciurus carolinensis (EGS) has been introduced to California and has expanded its geographic range since initial introductions. In this study we projected the potential future geographic range of the EGS in California using Maxent to create an ecological niche model. Location data were obtained over the time period of 2004 - 2015 from museum specimens, wildlife rehabilitation centers, the California Department of Public Health, the California Roadkill Observation System, and non-iNaturalist citizen science observations. Research grade data from iNaturalist was obtained over the time period of 2004 - 2018. Range and habitat suitability maps were developed by mapping ...


First Record Of The Family Peltidiidae (Copepoda; Harpacticoida) From The Gulf Of Mexico, With The Description Of A New Species Of Peltidium, Carlos Varela, Samuel Gomez Jan 2018

First Record Of The Family Peltidiidae (Copepoda; Harpacticoida) From The Gulf Of Mexico, With The Description Of A New Species Of Peltidium, Carlos Varela, Samuel Gomez

Bulletin of the Southern California Academy of Sciences

Female harpacticoid copepod specimens representing an undescribed species of Peltidium (Peltidiidae) were found from an unidentified species of Sargassum during a series of samplings carried out in 2014 in Tampa Bay, Florida, U.S.A. The new species, Peltidium camilae, is similar to P. nichollsi Geddes, 1968 and P. lerneri Geddes, 1968. These species share the female exopod of leg 5 with two inner and three apical setae, the second endopodal segment of leg 1 with three setae, and the third endopodal segment of legs 2-4 with three, five and four setae, respectively. Peltidium camilae n. sp. can be distinguished ...


Comparison Of The Polychaetous Annelids Populations On Suspended Test Panels In Los Angeles Harbor In 1950-1951 With The Populations In 2013-2014, Donald J. Reish Dr., Thomas Geringer, Rick Ware Jan 2018

Comparison Of The Polychaetous Annelids Populations On Suspended Test Panels In Los Angeles Harbor In 1950-1951 With The Populations In 2013-2014, Donald J. Reish Dr., Thomas Geringer, Rick Ware

Bulletin of the Southern California Academy of Sciences

A 14-month study was conducted of the polychaetous annelids present on attached wooden blocks replaced monthly and quarterly at nine stations in Los Angeles Harbor in 2013-2014 and compared to the results conducted at the same stations in 1950-1951. Many environmental changes have occurred in the harbors over the past 63 years. The harbor has been expanded into the outer harbor, channels have been deepened and pollution abatement programs initiated. The water quality has been improved as a result of these changes especially in the inner harbor area where the dissolved oxygen in the water was low or absent in ...


Geometric Morphometric Differentiation Of Two Western Usa Lizards (Phrynosomatidae: Squamata): Uta Stansburiana And Urosaurus Ornatus, With Implications For Fossil Identification, Julie Rej, Jim I. Mead Jan 2017

Geometric Morphometric Differentiation Of Two Western Usa Lizards (Phrynosomatidae: Squamata): Uta Stansburiana And Urosaurus Ornatus, With Implications For Fossil Identification, Julie Rej, Jim I. Mead

Bulletin of the Southern California Academy of Sciences

Squamate fossil identification has been challenging due to the incomplete understanding and sometimes complete lack of osteological research of extant species. Here we compared the maxilla of two similar species of phrynosomatids: Uta stansburiana (Common Side-blotched Lizard) and Urosaurus ornatus (Ornate Tree Lizard). Through landmark-based geometric morphometric analyses, we determined which characters significantly separated the two species. A principle component analysis (PCA) and a stepwise discriminant function analysis (DFA) were conducted, in which we compared 15 landmarks between U. stansburiana and U. ornatus. Both the PCA and stepwise DFA showed separation between the two species. The stepwise DFA selected five ...


Distribution Of The Eastern Gray Squirrel (Sciurus Carolinensis) Within California As Of 2015, Carly M. Creley, Alan E. Muchlinski Jan 2017

Distribution Of The Eastern Gray Squirrel (Sciurus Carolinensis) Within California As Of 2015, Carly M. Creley, Alan E. Muchlinski

Bulletin of the Southern California Academy of Sciences

Abstract - The goals of this study were to map the distribution of the invasive eastern gray squirrel, Sciurus carolinensis, in California as of 2015 and to assess range expansion since the first documented sightings within the state. Range maps exist, but the last update by the California Department of Fish and Wildlife was in 2007. An assessment of the rate of range expansion over time has not been conducted, but comparisons between the locations of initial sightings and the current distribution are included. Location data were obtained from museum specimens, wildlife rehabilitation centers, a roadkill database, and research-grade citizen observations ...


Does Estuary Restoration Design Alter The Fine Scale Movements Of Grey Smoothhounds (Mustelus Californicus) In Southern California?, Ryan M. Freedman, Mario Espinoza, Kelley Voss, Thomas Farrugia, Christine R. Whitcraft, Christopher Lowe Jan 2017

Does Estuary Restoration Design Alter The Fine Scale Movements Of Grey Smoothhounds (Mustelus Californicus) In Southern California?, Ryan M. Freedman, Mario Espinoza, Kelley Voss, Thomas Farrugia, Christine R. Whitcraft, Christopher Lowe

Bulletin of the Southern California Academy of Sciences

Restored estuaries in southern California are limited in size and shape by fragmentation from human development, which can in turn restrict habitat use. Thus, it is important to assess how habitat design affects how fish use restored estuaries. Acoustic telemetry tracking from prior studies revealed that Grey Smoothhounds (Mustelus californicus) used primarily the eelgrass ecotone and warm interior waters in Bolsa Chica Full Tidal Basin (BCFTB), a 1.48 km2 open-format marine dominated estuary. In this study, M. californicus utilized the Channel in Huntington Beach Wetlands Complex (HBWC), a smaller creek estuary. The Channel had more eelgrass than other available ...


Nudibranch Range Shifts Associated With The 2014 Warm Anomaly In The Northeast Pacific, Jeffrey Hr Goddard, Nancy Treneman, William E. Pence, Douglas E. Mason, Phillip M. Dobry, Brenna Green, Craig Hoover Apr 2016

Nudibranch Range Shifts Associated With The 2014 Warm Anomaly In The Northeast Pacific, Jeffrey Hr Goddard, Nancy Treneman, William E. Pence, Douglas E. Mason, Phillip M. Dobry, Brenna Green, Craig Hoover

Bulletin of the Southern California Academy of Sciences

Abstract.—The Northeast Pacific Ocean was anomalously warm in 2014, despite ENSO-neutral conditions in the tropical Pacific. We documented northern range shifts associated with this anomaly for 30 species of nudibranchs and other shallow-water, benthic heterobranch gastropods from southern California to southern Oregon. Nine of these (Placida cremoniana, Trapania velox, Doriopsilla fulva, Janolus anulatus, J. barbarensis, Flabellina cooperi, Anteaeolidiella chromosoma, A. oliviae, and Noumeaella rubrofasciata) were recorded from new northernmost localities, while the remainder were found at or near northern range limits established mainly during past El Niño events. All 30 species have planktotrophic larval development, and six were observed ...


The Bigeye Scad, Selar Crumenophthalmus (Bloch, 1793) (Family Carangidae), New To The California Marine Fauna, With A List To And Keys For All California Carangids, Milton S. Love, Julianne Kalman Passarelli, Chris Okamoto, Dario W. Diehl Jan 2016

The Bigeye Scad, Selar Crumenophthalmus (Bloch, 1793) (Family Carangidae), New To The California Marine Fauna, With A List To And Keys For All California Carangids, Milton S. Love, Julianne Kalman Passarelli, Chris Okamoto, Dario W. Diehl

Bulletin of the Southern California Academy of Sciences

We report on the collection of a Selar crumenophthalmus (Bloch, 1793), the bigeye scad. The fish was captured in the midwaters of a kelp bed (bottom depth 8 m) off northern Rancho Palos Verdes (33°48'N, 118°24'W), southern California. This is the first time this species has been reported from off California. The fish was one of approximately 10 conspecifics that were swimming with a school of juvenile jack mackerel, Trachurus symmetricus (Ayres, 1855). In addition to the report of this capture, we provide a list to and keys for all California carangids.


Records Of Wahoo, Acanthocybium Solandri (Scombridae), From California, Richard F. Feeney, Robert N. Lea Jan 2016

Records Of Wahoo, Acanthocybium Solandri (Scombridae), From California, Richard F. Feeney, Robert N. Lea

Bulletin of the Southern California Academy of Sciences

No abstract provided.


Nelson’S Big Horn Sheep (Ovis Canadensis Nelsoni) Trample Agassiz’S Desert Tortoise (Gopherus Agassizii) Burrow At A California Wind Energy Facility, Mickey M. Agha, David Delaney, Jeffrey E. Lovich, Jessica Briggs, Meaghan Austin, Steven J. Price Jul 2015

Nelson’S Big Horn Sheep (Ovis Canadensis Nelsoni) Trample Agassiz’S Desert Tortoise (Gopherus Agassizii) Burrow At A California Wind Energy Facility, Mickey M. Agha, David Delaney, Jeffrey E. Lovich, Jessica Briggs, Meaghan Austin, Steven J. Price

Bulletin of the Southern California Academy of Sciences

No abstract provided.


From Progesterone In Biopsies To Estimates Of Pregnancy Rates: Large Scale Reproductive Patterns Of Two Sympatric Species Of Common Dolphin, Delphinus Spp. Off California, Usa And Baja, Mexico, Nicholas Marc Kellar, Marisa L. Trego, Susan J. Chivers, Fredrick I. Archer, Wayne L. Perryman Sep 2014

From Progesterone In Biopsies To Estimates Of Pregnancy Rates: Large Scale Reproductive Patterns Of Two Sympatric Species Of Common Dolphin, Delphinus Spp. Off California, Usa And Baja, Mexico, Nicholas Marc Kellar, Marisa L. Trego, Susan J. Chivers, Fredrick I. Archer, Wayne L. Perryman

Bulletin of the Southern California Academy of Sciences

Blubber progesterone levels were measured in biopsy samples and used to predict the pregnancy status of 507 female common dolphins (204 long-beaked common dolphins, Delphinus capensis, and 303 short-beaked common dolphins, D. delphis). Samples were collected in the coastal waters of the eastern North Pacific between central California, USA and the southern end of Baja California, Mexico. The percentage of females pregnant was similar between the two species: 22.1% (n = 45) of D. capensis and 28.1% (n = 85) of D. delphis. For both species we found strong geographic patterns in pregnancy, suggesting that some areas were more conducive ...


Developmental Mode In Opisthobranch Molluscs From The Northeast Pacific Ocean: Additional Species From Southern California And Supplemental Data, Jeffrey H. R. Goddard, Brenna Green Sep 2013

Developmental Mode In Opisthobranch Molluscs From The Northeast Pacific Ocean: Additional Species From Southern California And Supplemental Data, Jeffrey H. R. Goddard, Brenna Green

Bulletin of the Southern California Academy of Sciences

We document development type for 33 species of benthic opisthobranch gastropods – 15 for the first time – collected mainly from the Southern California Bight. Fourteen of the newly examined species had planktotrophic development, while the dorid nudibranch Atagema alba had capsular metamorphic development, the first example of direct development in a non-dendrodoridid nudibranch known from the northeast Pacific Ocean. For the remaining 18 species our new data are either consistent with earlier determinations of development type, or confirm previous inferences. The new data also broaden geographic coverage for some species, and for the sacoglossan Stiliger fuscovittatus and the nudibranch Melibe leonina ...


Recent Mass Mortality Of Strongylocentrotus Purpuratus (Echinodermata: Echinoidea) At Malibu And A Review Of Purple Sea Urchin Kills Elsewhere In California, Gordon Hendler Apr 2013

Recent Mass Mortality Of Strongylocentrotus Purpuratus (Echinodermata: Echinoidea) At Malibu And A Review Of Purple Sea Urchin Kills Elsewhere In California, Gordon Hendler

Bulletin of the Southern California Academy of Sciences

Mass mortalities of intertidal purple sea urchins, Strongylocentrotus purpuratus occurred at Malibu Lagoon State Beach, California, in 2010 and 2011. Both events followed the first heavy rain of the season, and coincided with an illegal breaching of the lagoon. Osmotic shock from low-salinity lagoon water, the likely cause of death, may have acted jointly with stress from exposure during especially low tides. Comparable die-offs of purple sea urchins have occurred at other localities after exposure to brackish water or thermal shock. Annually recurring lagoon ruptures at Malibu, combined with predation by western gulls, can have a profound impact on the ...


Genetic Structure Of Polycera Alabe And P. Atra (Mollusca: Opistobranchia: Nudibranchia) In The Pacific Coast Of North America, Monica Santander, Angel Valdes Jan 2013

Genetic Structure Of Polycera Alabe And P. Atra (Mollusca: Opistobranchia: Nudibranchia) In The Pacific Coast Of North America, Monica Santander, Angel Valdes

Bulletin of the Southern California Academy of Sciences

Polycera alabe and Polycera atra are closely related opisthobranch sea slugs found in coastal habitats along the eastern Pacific. Both species are extremely variable in external coloration and some of this variation appears to be correlated with geographic range. To determine the phylogenetic relationships and genetic structure of P. alabe and P. atra molecular phylogenies were generated using two genes: H3 (nuclear) and 16S (mitochondrial). Sequence data indicate that populations of P. atra are genetically homogeneous and lack geographic structure along the range of the species. In contrast, Polycera alabe consists of three previously unrecognized, distinct clades with overlapping ranges ...


Correction Of Locality Records For The Endangered Arroyo Toad (Anaxyrus Californicus) From The Desert Region Of Southern California, Edward L. Ervin, Kent R. Beaman, Robert N. Fisher Jan 2013

Correction Of Locality Records For The Endangered Arroyo Toad (Anaxyrus Californicus) From The Desert Region Of Southern California, Edward L. Ervin, Kent R. Beaman, Robert N. Fisher

Bulletin of the Southern California Academy of Sciences

The recovery strategy for an endangered species requires accurate knowledge of its distribution and geographic range. Although the best available information is used when developing a recovery plan, uncertainty often remains in regard to a species actual geographic extent. The arroyo toad (Anaxyrus californicus) occurs almost exclusively in coastal drainages, from Monterey County, California, south into northwestern Baja California, Mexico. Through field reconnaissance and the study of preserved museum specimens we determined that the four reported populations of the arroyo toad from the Sonoran Desert region of Riverside, San Diego, and Imperial counties, California are in error. Two additional sites ...


Distribution Of The Coast Horned Lizard, Phrynosoma Coronatum, In Southern California, Bayard H. Brattstrom Jan 2013

Distribution Of The Coast Horned Lizard, Phrynosoma Coronatum, In Southern California, Bayard H. Brattstrom

Bulletin of the Southern California Academy of Sciences

In order to access the endangered species status of any organism it is essential to know its past and present distribution. The Coast Lizard, Phrynosoma coronatum , was presumed to be threatened by habitat destruction due to human activities. I used historical literature and museum records to access past, and lizard survey teams to access current range and population numbers of P. coronatum in the five counties of Southern California between 1989-1991. The species occurs from sea level to 8,000’ (2440m) in a wide variety of habitats. Fieldwork and questionnaires increased by a third the number of locations (from 672 ...


Structural Irregularities In Sagittal Otoliths Of Black Croaker (Cheilotrema Saturnum) From Southern California, Eric F. Miller Nov 2012

Structural Irregularities In Sagittal Otoliths Of Black Croaker (Cheilotrema Saturnum) From Southern California, Eric F. Miller

Bulletin of the Southern California Academy of Sciences

No abstract provided.


Reproduction In Cope’S Leopard Lizard, Gambelia Copeii (Squamata: Crotaphytidae), Stephen R. Goldberg, Clark R. Mahrdt, Kent R. Beaman Nov 2012

Reproduction In Cope’S Leopard Lizard, Gambelia Copeii (Squamata: Crotaphytidae), Stephen R. Goldberg, Clark R. Mahrdt, Kent R. Beaman

Bulletin of the Southern California Academy of Sciences

No abstract provided.


Avian Material From Rancho Del Oro, A Pleistocene Locality In San Diego County, California, Daniel Guthrie Nov 2012

Avian Material From Rancho Del Oro, A Pleistocene Locality In San Diego County, California, Daniel Guthrie

Bulletin of the Southern California Academy of Sciences

Late Pleistocene avifaunal material from a construction site in Oceanside, California is described. The material includes 77 bones from 21 species, only one of which (Podiceps parvus) is extinct. Two previously described Pleistocene species (Oxyura bessomi and Bucephala fossilis) are placed in extant species. The first fossil record for Phalaropus lobatus is recorded.


Cetacean Ecology For Santa Monica Bay And Nearby Areas, California In The Context Of The Newly Established Mpas, Maddalena Bearzi, Charles A. Saylan Oct 2012

Cetacean Ecology For Santa Monica Bay And Nearby Areas, California In The Context Of The Newly Established Mpas, Maddalena Bearzi, Charles A. Saylan

Bulletin of the Southern California Academy of Sciences

Data on cetacean ecology are important for monitoring animals and developing conservation and management strategies in a specific area, and are crucial in the decision making process during the creation of marine protected areas (MPAs). Cetacean occurrence, distribution and behavior were investigated in Santa Monica Bay, California (1997-2007). A total of 425 boat-based surveys documented three species inhabiting the bay year-round - the common bottlenose dolphin, Tursiops truncatus, the long-beaked common dolphin, Delphinus capensis, and the short-beaked common dolphin, D. delphis - and ten species occurring occasionally. Coastal bottlenose dolphins were mostly found traveling, diving and feeding in waters within 0.5km ...


A Previously Unreported Locality Record For The Gila Monster, Jeff Lovich, Gordon Haxel Oct 2012

A Previously Unreported Locality Record For The Gila Monster, Jeff Lovich, Gordon Haxel

Bulletin of the Southern California Academy of Sciences

Gila Monsters (Heloderma suspectum) are rarely seen in California with only 27 credible sightings reported in over 150 years. A previously unreported specimen was observed 30 April, 1974 near Black Mountain in the southern Chocolate Mountains of Imperial County. The area fits many of the criteria of Gila Monster habitat elsewhere in California and is relatively close to several other credible and possible records in the state.


Abundance Of Long-Beaked Common Dolphin (Delphinus Capensis) In California And Western Baja California Waters Estimated From A 2009 Ship-Based Line-Transect Survey, James V. Carretta, Susan J. Chivers, Wayne L. Perryman Oct 2012

Abundance Of Long-Beaked Common Dolphin (Delphinus Capensis) In California And Western Baja California Waters Estimated From A 2009 Ship-Based Line-Transect Survey, James V. Carretta, Susan J. Chivers, Wayne L. Perryman

Bulletin of the Southern California Academy of Sciences

The abundance of the long-beaked common dolphin (Delphinus capensis) is estimated from data collected during a 2009 ship-based line-transect survey. The survey was designed to provide fine-scale coverage of the known range of D. capensis along the California and west Baja California coasts. Estimates of D. capensis abundance presented are the highest to date for California waters and may reflect a combination of improved survey design for this species and increasing numbers of D. capensis in state waters. Estimates of D. capensis abundance within California waters are 183,396 (CV=0.41, 95% CI 78,149 – 379,325) animals. An ...


Documentation Of Replacement Of Native Western Gray Squirrels By Introduced Eastern Fox Squirrels, Alan E. Muchlinski, Glenn R. Stewart, Julie L. King, Suzanne A. Lewis Jan 2009

Documentation Of Replacement Of Native Western Gray Squirrels By Introduced Eastern Fox Squirrels, Alan E. Muchlinski, Glenn R. Stewart, Julie L. King, Suzanne A. Lewis

Bulletin of the Southern California Academy of Sciences

The eastern fox squirrel (Sciurus niger) was first introduced to Los Angeles in 1904. Since that time, this species has spread throughout many of the urban and suburban areas of Los Angeles, Ventura and Orange Counties. In this paper we document that the eastern fox squirrel can replace the western gray squirrel within a particular habitat in a short period of time.


An Initial Carnivore Survey Of Griffith Park, Los Angeles, California, Paul D. Mathewson, Stephanie N. Spehar, Daniel S. Cooper Jan 2008

An Initial Carnivore Survey Of Griffith Park, Los Angeles, California, Paul D. Mathewson, Stephanie N. Spehar, Daniel S. Cooper

Bulletin of the Southern California Academy of Sciences

We established 42 carnivore detection stations in Griffith Park, Los Angeles, CA, in June 2007 to gather baseline information about wildlife species in the park. We documented the widespread presence of coyotes (Canis latrans), striped skunks (Mephitis mephitis), and raccoons (Procyon lotor), and the localized presence of bobcats (Lynx rufus), gray foxes (Urocyon cinereoargenteus), and Virginia opossums (Didelphis virginiana). Carnivore diversity and detection rates were greatest at the park’s borders and along wooded canyons. Our data suggest a possible avoidance of areas heavily used by hikers and dogs, despite the presence of suitable habitat. This represents Griffith Park’s ...


Habitat Partitioning By Two Sympatric Species Of Chipmunk (Genus: Neotamias) In The Warner Mountains Of California, Mary Poffenroth, John O. Matson Jan 2007

Habitat Partitioning By Two Sympatric Species Of Chipmunk (Genus: Neotamias) In The Warner Mountains Of California, Mary Poffenroth, John O. Matson

Bulletin of the Southern California Academy of Sciences

In the Warner Mountains of California, two sympatric species of chipmunk partition their habitat primarily through the mechanism of competitive exclusion by social dominance and aggressive interactions. Forests are optimal habitats for both Neotamias amoenus and N. minimus. In this study N. amoenus actively excludes N. minimus from the forest through successful aggressive interspecific interactions, leaving N. minimus to occupy primarily the arid sagebrush scrub. Neotamias amoenus was observed to be the more social species. Neotamias minimus appears to lack the level of social structure of N. amoenus and was not observed to win any aggressive encounters. Neotamias minimus avoids ...


Microhabitat Segregation Of Three Species Of Pocket Mice (Genus Chaetodipus) In Coastal Baja California, Mexico, Paul Stapp Jan 2005

Microhabitat Segregation Of Three Species Of Pocket Mice (Genus Chaetodipus) In Coastal Baja California, Mexico, Paul Stapp

Bulletin of the Southern California Academy of Sciences

I compared vegetation and substrate characteristics at capture locations of three syntopic species of pocket mice (Chaetodipus: Heteromyidae) to determine differences in microhabitat affinities of these ecologically similar rodents in coastal Baja California, Me´xico. Principal components analysis revealed that capture locations of C. spinatus had disproportionately higher cover of medium and large rocks, and tended to have higher plant species diversity than capture locations of the other two species. C. spinatus and C. arenarius, the two smallest species, differed most in their microhabitat affinities, suggesting spatial segregation that may minimize competition for similar food resources. C. arenarius was captured ...