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Articles 2731 - 2760 of 3569

Full-Text Articles in Population Biology

Crisis Global De Biodiversidad: Importancia De La Diversidad Genética Y La Extinción De Anfibios, Rafael O. De Sá Jan 2005

Crisis Global De Biodiversidad: Importancia De La Diversidad Genética Y La Extinción De Anfibios, Rafael O. De Sá

Biology Faculty Publications

El mundo enfrenta, por primera vez desde el comienzo de la civilización, el declive y la extinción de una clase de vertebrados, los anfibios. Esta extinción aparenta ser un evento global y de la magnitud que llevó a la desaparición de los dinosaurios. Muchas son las posibles causas de esta extinción y el efecto combinado de estos factores agravan la situación. La pérdida de ambientes naturales permanece como el factor más crítico en el declive de anfibios, pero enfermedades infecciosas emergentes parecen ser responsables de mortalidades masivas en décadas recientes. El declive y extinción de anfibios representa una llamada urgente …


Proposed Management Arrangements For The West Coast Commercial 'Wetline' Fishery. A Discussion Paper., West Coast And Gascoyne Management Planning Panel Jan 2005

Proposed Management Arrangements For The West Coast Commercial 'Wetline' Fishery. A Discussion Paper., West Coast And Gascoyne Management Planning Panel

Fisheries management papers

The ‘Wetline Review’ was established to implement an effective management framework for the commercial sector to complement the recreational initiatives. It must be stressed at the outset that this review is focussed on the take of scalefish by the commercial sector. The levels of use between the various user groups in the West Coast region will be examined under the new integrated fisheries initiative following the implementation of new management arrangements for scalefish taken by the commercial sector.


Monitoring Temporal Change In Riparian Vegetation Of Great Basin National Park, E. A. Beever, D. A. Pyke, J. C. Chambers, F. Landau, S. D. Smith, K. Murray Jan 2005

Monitoring Temporal Change In Riparian Vegetation Of Great Basin National Park, E. A. Beever, D. A. Pyke, J. C. Chambers, F. Landau, S. D. Smith, K. Murray

Life Sciences Faculty Research

Disturbance in riparian areas of semiarid ecosystems involves complex interactions of pulsed hydrologic flows, herbivory, fire, climatic effects, and anthropogenic influences. We resampled riparian vegetation within ten 10-m × 100-m plots that were initially sampled in 1992 in 4 watersheds of the Snake Range, east central Nevada. Our finding of significantly lower coverage of grasses, forbs, and shrubs within plots in 2001 compared with 1992 was not consistent with the management decision to remove livestock grazing from the watersheds in 1999. Change over time in cover of life-forms or bare ground was not predicted by scat counts within plots in …


Ecology Of The Missouri River. Progress Report, Dingell-Johnson Project F-75-R-23, Supplement I - Missouri River Creel Survey, Bellevue To Camp Creek, 2 April Through 14 October 2005, Gerald Mestl Jan 2005

Ecology Of The Missouri River. Progress Report, Dingell-Johnson Project F-75-R-23, Supplement I - Missouri River Creel Survey, Bellevue To Camp Creek, 2 April Through 14 October 2005, Gerald Mestl

Nebraska Game and Parks Commission: White Papers, Conference Presentations, and Manuscripts

This report describes Missouri River activities and results related to a channelized Missouri River creel survey conducted from 2 April through 14 October 2005. This is the sixth of a planned annual creel survey to be conducted on alternating sections of the channelized Missouri River to measure changes in recreational fishing activity, especially those changes due to large scale habitat restoration efforts. We returned to the Bellevue to Camp Creek reach in 2005 because we had to cancel the creel on this reach in 2004 after the second creel period due to lack of personnel. Future reports will contain additional …


Initial Training Of Cranes For An Airship Migration, David H. Ellis, Glenn H. Olsen, Jared Kwitowski Jan 2005

Initial Training Of Cranes For An Airship Migration, David H. Ellis, Glenn H. Olsen, Jared Kwitowski

Proceedings of the North American Crane Workshop

We describe the first year of our efforts to train cranes to accept the unnatural stimuli associated with being transported south in cages suspended beneath an airship. All 4 experimental cranes readily acclimated to entering a suspended cage and were trained to accept being jostled while in the cage, even when the cage was transported in the back of a pickup truck. With minor changes, the training protocol is ready for use in an actual airship migration.


Crop Depredations By Cranes At Daursky State Biosphere Reserve, Siberia, Stephen H. Bouffard, John E. Cornely, Oleg A. Goroshko Jan 2005

Crop Depredations By Cranes At Daursky State Biosphere Reserve, Siberia, Stephen H. Bouffard, John E. Cornely, Oleg A. Goroshko

Proceedings of the North American Crane Workshop

Crop depredations by staging cranes have been an annual problem at Daursky State Biosphere Reserve in southern Siberia. In September 2001 we met at Daursky when crane populations peaked to investigate the problem and suggest methods to reduce damages. Peak of crane staging coincided with grain harvest. We counted ≈ 30,000 cranes of 5 species, primarily demoiselles (Anthropoides virgo), in the area. Poor grain yields and cooperative farming systems discouraged efforts to reduce damage. Moving crops further from roost areas may be the most reasonable short term control method, but it’s effectiveness is yet untested. Hazing, lure crops …


Annual Movements Of Pacific Coast Sandhill Cranes, Gary L. Ivey, Caroline P. Herziger, Thomas J. Hoffmann Jan 2005

Annual Movements Of Pacific Coast Sandhill Cranes, Gary L. Ivey, Caroline P. Herziger, Thomas J. Hoffmann

Proceedings of the North American Crane Workshop

The subspecies composition of migratory sandhill cranes (Grus canadensis) which stage and winter along the Lower Columbia River in northwest Oregon and southwest Washington is uncertain, but may include all 3 using the Pacific Flyway: lesser (G. c. canadensis), Canadian (G. c. rowani), and greater (G. c. tabida). However, the status of rowani has been debated. During 2001-02, we captured and marked 8 cranes using a noose line trapping technique, and attached Platform Transmitter Terminals (PTTs) to 6 to ascertain locations of their breeding areas, migration corridors and winter sites. Morphometric data …


Techniques Employed To Capture Whooping Cranes In Central Florida, Martin J. Folk, Stephen A. Nesbitt, Stephen T. Schwikert, James A. Schmidt, Kathleen A. Sullivan, Thomas J. Miller, Stephen B. Baynes, Jeannette M. Parker Jan 2005

Techniques Employed To Capture Whooping Cranes In Central Florida, Martin J. Folk, Stephen A. Nesbitt, Stephen T. Schwikert, James A. Schmidt, Kathleen A. Sullivan, Thomas J. Miller, Stephen B. Baynes, Jeannette M. Parker

Proceedings of the North American Crane Workshop

During the course of re-introduction of a non-migratory flock of whooping cranes to Florida (1993-2002) a variety of techniques were used to capture 105 free-living birds. The most commonly used technique was hand-capture from a feed trough blind (45 birds). Whooping cranes were also captured by use of snares, several types of nets, and by hand. All techniques were relatively safe and posed little risk to the birds, a primary concern when dealing with rare birds. We found it useful to employ a diversity of techniques because some methods work better than others under differing circumstances. Capturing whooping cranes for …


Migration Routes, Staging Areas, And Wintering Grounds Of Sandhill Cranes That Breed In Siberia, Gary L. Krapu, David A. Brandt Jan 2005

Migration Routes, Staging Areas, And Wintering Grounds Of Sandhill Cranes That Breed In Siberia, Gary L. Krapu, David A. Brandt

Proceedings of the North American Crane Workshop

We determined breeding sites, migration routes, spring and fall staging areas, and wintering grounds for sandhill cranes (Grus canadensis) from the midcontinent population that nest in Siberia. Our results are from 30 PTT-marked individuals captured and marked along the Platte and North Platte Rivers in Nebraska. Findings indicate the species breeds across a vast area of northeastern Siberia extending at least 1500 km west from near the Bering Strait to the Kolymskaya Plains with most breeding confined to within 75 km of the coast. We describe when PTT-tagged cranes arrived at breeding sites in Siberia, duration of stay, …


Die Parasitierung Der Luzerne-Blattschneiderbiene, Megachile Rotundata (Hymenoptera: Megachilidae), Durch Physocephala Pusilla (Diptera: Conopidae) In Der Mongolei = Parasitization Of The Alfalfa Leaf-Cutter Bee, Megachile Rotundata (Hymenoptera: Megachilidae), By Physocephala Pusilla (Diptera: Conopidae) In Mongolia, Karsten Seidelmann Jan 2005

Die Parasitierung Der Luzerne-Blattschneiderbiene, Megachile Rotundata (Hymenoptera: Megachilidae), Durch Physocephala Pusilla (Diptera: Conopidae) In Der Mongolei = Parasitization Of The Alfalfa Leaf-Cutter Bee, Megachile Rotundata (Hymenoptera: Megachilidae), By Physocephala Pusilla (Diptera: Conopidae) In Mongolia, Karsten Seidelmann

Erforschung biologischer Ressourcen der Mongolei / Exploration into the Biological Resources of Mongolia, ISSN 0440-1298

Physocephala pusilla Meigen (Diptera: Conopidae) was found to be a dangerous endoparasitoid of the alfalfa leafcutter bee Megachile rotundata F. (Hymenoptera: Megachilidae) in Mongolia. The conopid fly parasitizes adults and causes their early death. In 1989 and 1990, 16% and 15% respectively of the M. rotundata females were found dead in front of the bee shelter. However, the number of bees (females and males) dying in the field is unknown. These bees cause a contamination of the alfalfa fields due to an increase of the conopid population. Therefore, Ph. pusilla becomes a serious problem for the management of M. rotundata …


Effects Of Urbanization On The Distribution And Abundance Of Amphibians And Invasive Species In Southern California Streams, Seth Riley, Gary Busteed, Lee Kats, Thomas Vandergon, Lena Lee, Rosi Dagit, Jacob Kerby, Robert Fisher, Raymond Sauvajot Dec 2004

Effects Of Urbanization On The Distribution And Abundance Of Amphibians And Invasive Species In Southern California Streams, Seth Riley, Gary Busteed, Lee Kats, Thomas Vandergon, Lena Lee, Rosi Dagit, Jacob Kerby, Robert Fisher, Raymond Sauvajot

Lee Kats

Urbanization negatively affects natural ecosystems in many ways, and aquatic systems in particular. Urbanization is also cited as one of the potential contributors to recent dramatic declines in amphibian populations. From 2000 to 2002 we determined the distribution and abundance of native amphibians and ex- otic predators and characterized stream habitat and invertebrate communities in 35 streams in an urbanized landscape north of Los Angeles (U.S.A.). We measured watershed development as the percentage of area within each watershed occupied by urban land uses. Streams in more developed watersheds often had exotic crayfish ( Procambarus clarkii) and fish, and had fewer …


The Yosemite Butterflies (Text), And The Yosemite Butterflies (Text): Supplement Of Additional Information, Collections And Corrections For Volume 5, No. 1, Kenneth E. Davenport Dec 2004

The Yosemite Butterflies (Text), And The Yosemite Butterflies (Text): Supplement Of Additional Information, Collections And Corrections For Volume 5, No. 1, Kenneth E. Davenport

The Taxonomic Report of the International Lepidoptera Survey

The current checklist covers the 170 known species and additional 48 subspecies known to occur in the Yosemite region, California, United States. This represents a total of 218 taxa (some being undescribed and unnamed) now recognized in the study area. This compares with Garth and Tilden’s 1963 survey which recognized 134 species and 16 additional subspecies, a total of 150 taxa. In addition to those, six additional species reported from the region are “questionable or doubtful” and another six species occur just outside the defined region.

The supplement includes additional information for the benefit of those who obtained the first …


Online Atmospherics: An Investigation Of Feeling And Internet Purchase Intention, Kelly Price Rankin Dec 2004

Online Atmospherics: An Investigation Of Feeling And Internet Purchase Intention, Kelly Price Rankin

Doctoral Dissertations

This study examines the online atmospheric cues of color and music and their impact upon feeling, attitude and purchase intention of consumers in the online environment. The research design was experimental and used data from a questionnaire. A pilot test of the instrument was conducted. The final questionnaire contained 39 items and a demographic section. A total of 200 questionnaires were collected. Participants were randomly assigned to one of four groups. Each group of 50 participants was exposed to a specific set of online atmospheric elements. The results indicated that Hypotheses 1, 3 and 4 were rejected while Hypotheses 2 …


Predators In Natural Fragments: Foraging Ecology Of Wolves In British Columbia’S Central And North Coast Archipelago, C. T. Darimont, M. H. H. Price, N. N. Winchester, J. Gordon-Walker, P. C. Paquet Nov 2004

Predators In Natural Fragments: Foraging Ecology Of Wolves In British Columbia’S Central And North Coast Archipelago, C. T. Darimont, M. H. H. Price, N. N. Winchester, J. Gordon-Walker, P. C. Paquet

Biogeography and Ecological Opportunity Collection

Aim Predator–prey dynamics in fragmented areas may be influenced by spatial features of the landscape. Although little is known about these processes, an increasingly fragmented planet underscores the urgency to predict its consequences. Accordingly, our aim was to examine foraging behaviour of an apex mammalian predator, the wolf (Canis lupus), in an archipelago environment.

Location Mainland and adjacent archipelago of British Columbia, Canada; a largely pristine and naturally fragmented landscape with islands of variable size and isolation.

Methods We sampled 30 mainland watersheds and 29 islands for wolf faeces in summers 2000 and 2001 and identified prey remains. We examined …


Apparent Sibling Rivalry In The Freshwater Clam Sphaerium Striatinum, Mark Beekey, Ronald H. Karlson Nov 2004

Apparent Sibling Rivalry In The Freshwater Clam Sphaerium Striatinum, Mark Beekey, Ronald H. Karlson

Biology Faculty Publications

In Sphaerium striatinum, a freshwater brooding bivalve, up to 97.5% of offspring that adults initially produce fail to reach independence. Marsupial sacs, specialized extensions of gill filaments that act as nurseries, initially contain multiple offspring in various sizes and stages of development. However, by the time offspring reach later stages of development, marsupial sacs typically contain only one offspring. Brood mortality is hypothesized to be the result of competition among embryos for nutrients and/or space. Sphaeriid eggs do not contain enough yolk for offspring to complete development. Adults supply additional nutrients required to reach independence. Brood capacity is limited by …


Description Of A Multilevel Cryptic New Species Of Phyciodes (Nymphalidae: Melitaeinae) From The Southern Appalachian Mountains, Ronald R. Gatrelle Sep 2004

Description Of A Multilevel Cryptic New Species Of Phyciodes (Nymphalidae: Melitaeinae) From The Southern Appalachian Mountains, Ronald R. Gatrelle

The Taxonomic Report of the International Lepidoptera Survey

Phyciodes incognitus is described as a new species from the medium to high elevation hardwood forests of the southern Appalachian Mountains, type locality: Duncan Ridge Road, 3,700 ft., Union County, Georgia, United States. Phyciodes incognitus is verified from four colonies in Union County, Georgia, United States, and Clay and Macon counties, North Carolina, United States. It is projected to range, in suitable habitat, as far north as montane Pennsylvania, United States (indicated by photos). Phyciodes incognitus possesses a unique set of character traits that are virtually identical to both P. tharos and P. cocyta but at differing character …


Zebra Mussels Affect Benthic Predator Foraging Success, Mark Beekey, D. J. Mccabe, I. E. Marsden Sep 2004

Zebra Mussels Affect Benthic Predator Foraging Success, Mark Beekey, D. J. Mccabe, I. E. Marsden

Biology Faculty Publications

The introduction of zebra mussels (Dreissena spp.) to North America has resulted in dramatic changes to the complexity of benthic habitats. Changes in habitat complexity may have profound effects on predator-prey interactions in aquatic communities. Increased habitat complexity may affect prey and predator dynamics by reducing encounter rates and foraging success. Zebra mussels form thick contiguous colonies on both hard and soft substrates. While the colonization of substrata by zebra mussels has generally resulted in an increase in both the abundance and diversity of benthic invertebrate communities, it is not well known how these changes affect the foraging efficiencies of …


A New Species Of Callulina (Anura: Microhylidae) From The West Usambara Mountains, Tanzania, Rafael O. De Sá, Simon P. Loader, Alan Channing Jun 2004

A New Species Of Callulina (Anura: Microhylidae) From The West Usambara Mountains, Tanzania, Rafael O. De Sá, Simon P. Loader, Alan Channing

Biology Faculty Publications

The description of the species Callulina kreffti was based on specimens collected in the East Usambara Mountains of Tanzania. Successive collecting has shown this species to be widely distributed through the Eastern Arc Mountains. Advertisement calls from populations in the type locality of Callulina kreffti were compared with calls from populations in the West Usambara Mountains. Analysis of the calls suggested that these two populations of Callulina represent two separate taxa. Subsequent morphological and molecular investigations indicated that these two populations are distinct. Herein, we describe a new Callulina species on the basis of call, morphology and molecular sequences.


A New Toad (Anura: Bufonidae) From Uruguay, Raúl Maneyro, Diego Arrieta, Rafael O. De Sá Jun 2004

A New Toad (Anura: Bufonidae) From Uruguay, Raúl Maneyro, Diego Arrieta, Rafael O. De Sá

Biology Faculty Publications

A new species of toad is described from small streams in the hills of Cuchilla de Haedo and Cuchilla Grande in northeastern Uruguay. Specimens of the new species were previously mistaken for Bufo arenarum; they differ from B.arenarum by having elongated parotoid glands and reddish-brown parotoid and cephalic crests. A discriminant analysis resulted in three groups corresponding to B. arenarum, Bufo rufus, and the specimens herein described as a new species.


A Concise Update Of The Information Provided In The Butterflies Of Southern California (1973) By Thomas C. Emmel And John F. Emmel, Kenneth E. Davenport May 2004

A Concise Update Of The Information Provided In The Butterflies Of Southern California (1973) By Thomas C. Emmel And John F. Emmel, Kenneth E. Davenport

The Taxonomic Report of the International Lepidoptera Survey

This paper’s purpose is to bring together in one resource a concise, but thorough, report on the current status of butterflies discussed in the Butterflies of Southern California by Thomas C. Emmel and John F. Emmel, published by the Natural History Museum of Los Angeles County, Los Angeles, California, United States. 1973. This update deals primarily with new species or subspecies, taxonomic matters, and new distributional information. The family order follows A Catalogue / Checklist of the Butterflies of America North of Mexico by Clifford D. Ferris, editor, published by the Lepidopterists’ Society as Memoir No. 3, 1989. Species order …


A Taxonomic Examination Of Harkenclenus Titus (Lycaenidae: Theclinae) In The Eastern United States: Recognition And Resolution Of Taxonomic Problems By The Delineation Of Old Names, Naming Of A Long Recongnized (But Heretofore Undescribed) Subspecies, And Description Of A Wide Ranging New Subspecies, Ronald R. Gatrelle Apr 2004

A Taxonomic Examination Of Harkenclenus Titus (Lycaenidae: Theclinae) In The Eastern United States: Recognition And Resolution Of Taxonomic Problems By The Delineation Of Old Names, Naming Of A Long Recongnized (But Heretofore Undescribed) Subspecies, And Description Of A Wide Ranging New Subspecies, Ronald R. Gatrelle

The Taxonomic Report of the International Lepidoptera Survey

Harkenclenus is retained per dos Passos 1970 as a genus distinct from Satyrium. The names titus and mopsus have long been considered to apply to two subspecies. These are demonstrated to be synonymous as both names are based on southeastern United States populations. The holotype of titus (Natural History Museum London) is examined and its type locality established as Screven County, Georgia, United States. A neotype is established for the synonymic name mopsus, type locality, Screven County, Georgia, United States. This leaves the long recognized northern subspecies without a name; it is described as new subspecies Harkenclenus titus …


Draft Aquaculure Plan For Exmouth Gulf, Department Of Fisheries Apr 2004

Draft Aquaculure Plan For Exmouth Gulf, Department Of Fisheries

Fisheries management papers

The Plan’s objective is to provide a sound strategy for developing future aquaculture activities in Exmouth Gulf, while at the same time conserving the unique environment of Exmouth Gulf for present and future generations, and minimising conflict with existing and future users of Exmouth Gulf.


Draft Aquaculture Plan For Shark Bay., Department Of Fisheries Apr 2004

Draft Aquaculture Plan For Shark Bay., Department Of Fisheries

Fisheries management papers

The Department of Fisheries has prepared this draft aquaculture plan for Shark Bay to provide an agreed framework for future management of aquaculture. The final plan will assist prospective aquaculturists in preparing proposals and will guide the Department of Fisheries in the decision making process for aquaculture licence and lease applications. The plan identifies constraints to aquaculture development and areas where aquaculture may occur. It also identifies species that may be used for aquaculture development. Implementation of this plan will ensure that aquaculture can occur in a sustainable manner, while retaining the unique features of Shark Bay.


Draft Plan Of Management For The Kalbarri Blue Holes Fish Habitat Protection Area., Department Of Fisheries Mar 2004

Draft Plan Of Management For The Kalbarri Blue Holes Fish Habitat Protection Area., Department Of Fisheries

Fisheries management papers

The overall objective of the proposed FHPA and the associated Plan of Management is to conserve and protect a portion of the near-shore reef ecosystem in the vicinity of the Blue Holes, and to manage activities within the area, to promote the observation and protection of fish living within the area. Strong community commitment has already been demonstrated, and this is crucial in the implementation of the proposed management plan


Fish Stock And Fishery Enhanceent In Western Australia. A Summary Report., Department Of Fisheries Mar 2004

Fish Stock And Fishery Enhanceent In Western Australia. A Summary Report., Department Of Fisheries

Fisheries management papers

This summary paper provides an overview of the key proposals set out in the full policy discussion paper, Fisheries Management Paper No 175. It does not discuss the theoretical background for the framework presented and therefore readers interested in such discussion are directed to Fisheries Management Paper No 175. Both papers have been prepared to encourage public involvement in the development of policy for stock enhancement within Western Australian waters. Stock enhancement can involve an existing fishery or creation of a new fishery through the translocation of fish. It affects both public and private waters.


The Hardy Inlet Estuarine Fishery Management Issues And Options, Department Of Fisheries Feb 2004

The Hardy Inlet Estuarine Fishery Management Issues And Options, Department Of Fisheries

Fisheries management papers

This paper presents information available on fish resources in the Hardy Inlet/Blackwood River system, and discusses the key management matters and likely impacts of a number of possible management measures.


On The Engimatic Distribution Of The Honduran Endemic Leptodactylus Silvanimbus (Amphibia: Anura: Leptodactylidae), W. R. Heyer, Rafael O. De Sá, Sarah Muller Jan 2004

On The Engimatic Distribution Of The Honduran Endemic Leptodactylus Silvanimbus (Amphibia: Anura: Leptodactylidae), W. R. Heyer, Rafael O. De Sá, Sarah Muller

Biology Faculty Publications

Most species of the frog genus Leptodactylus occur in South America, and all authors who have treated the zoogeography of the genus have concluded that it originated somewhere in South America (e.g., Savage 1982). Savage (1982, 518) summarized the historical herpetofaunal units of the Neotropics as follows: "All evidence points to an ancient contiguity and essential similarity of a generalized tropical herpetofauna that ranged over tropical North, Middle, and most of South America in Cretaceous-Paleocene times. Descendents of this fauna are represented today by the South and Middle American tracks (Elements). To the north of this fauna ranged a subtropical-temperate …


Distribución Geográfica De La Fauna De Anfibios Del Uruguay, Diego Nuñez, Raúl Maneyro, José A. Langone, Rafael O. De Sá Jan 2004

Distribución Geográfica De La Fauna De Anfibios Del Uruguay, Diego Nuñez, Raúl Maneyro, José A. Langone, Rafael O. De Sá

Biology Faculty Publications

Datos precises sobre la distribución geográfica de los organismos de una región son necesarios y prerrequisito para entender las interrelaciones ecológicas entre las comunidades biológicas. Esta información también contribuye a entender el componente histórico de la región posibilitando la determinación de centros de origen y el establecimiento de patrones de diversidad (Ron, 2000), así mismo posibilita realizar inferencias acerca de los mecanismos de especiación en los diferentes grupos zoológicos (Bridarolli & Di Tada, 1994).

La distribución geográfica de los anfibios en Uruguay ha sido parcialmente reportada (Achaval & Olmos, 1997; Langone, 1995; Maneyro et al, 1995; Maneyro & Langone, 2001). …


Características Histológicas De La Tumefacción Frontal De Melanophryniscus (Amphibia: Anura: Bufonidae), Daniel E. Naya, José A. Langone, Rafael O. De Sá Jan 2004

Características Histológicas De La Tumefacción Frontal De Melanophryniscus (Amphibia: Anura: Bufonidae), Daniel E. Naya, José A. Langone, Rafael O. De Sá

Biology Faculty Publications

Se analizó la histología tegumentaria de la región cefálica en seis especies del género Melanophryniscus, pertenecientes a los grupos stelzneri (4) y tumifrons (2), con el objetivo de esclarecer la estructura de la tumefacción frontal y su posible función. Las características generales de la histología del grupo stelzneri, coincidieron con las descripciones tegumentarias existentes para el género. Sin embargo, la región cefálica frontal en las dos especies del grupo tumifrons muestran cambios histológicos correlacionados a la tumefacción frontal. Esta estructura presenta una organización similar a otras macroglándulas presentes en la dermis de anuros (e.g., parotoides, paracnémicas), y por tanto se …


Stage-Specific And Interactive Effects Of Sedimentation And Trout On A Headwater Stream Salamander, Winsor H. Lowe, Keith H. Nislow, Douglas T. Bolger Jan 2004

Stage-Specific And Interactive Effects Of Sedimentation And Trout On A Headwater Stream Salamander, Winsor H. Lowe, Keith H. Nislow, Douglas T. Bolger

Dartmouth Scholarship

In species with complex life cycles, stage-specific effects of environmental conditions combine with factors regulating stage-specific recruitment to determine population-level response to habitat disturbance. The abundance of the stream salamander Gyrinophilus porphyriticus(Plethodontidae) is negatively related to both logging-associated sedimentation and brook trout (Salvelinus fontinalis) in headwater streams throughout New Hampshire, USA. To understand the mechanisms underlying these patterns, we investigated stage-specific and interactive effects of sedimentation and brook trout on G. porphyriticus. We conducted quantitative surveys of salamanders, brook trout, and substrate embeddedness in 15 first-order streams and used a controlled experiment to test the direct and interactive effects of …