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778 results on '"Spotila, James A."'

253. Olive Ridley Mass Nesting Ecology and Egg Harvest at Ostional Beach, Costa Rica

Author

Valverde, Roldán A., primary, Orrego, Carlos M., additional, Tordoir, Mark T., additional, Gómez, Flor M., additional, Solís, Diana S., additional, Hernández, Ricardo A., additional, Gómez, Gredy B., additional, Brenes, Laura S., additional, Baltodano, José P., additional, Fonseca, Luis G., additional, and Spotila, James R., additional

Published
2012
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255. Movement Patterns for a Critically Endangered Species, the Leatherback Turtle (Dermochelys coriacea), Linked to Foraging Success and Population Status

Author

Bailey, Helen, primary, Fossette, Sabrina, additional, Bograd, Steven J., additional, Shillinger, George L., additional, Swithenbank, Alan M., additional, Georges, Jean-Yves, additional, Gaspar, Philippe, additional, Strömberg, K. H. Patrik, additional, Paladino, Frank V., additional, Spotila, James R., additional, Block, Barbara A., additional, and Hays, Graeme C., additional

Published
2012
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270. Controls on the erosion and geomorphic evolution of the San Bernardino and San Gabriel Mountains, southern California

Author

Barth, Andrew, Spotila, James A., House, Martha A., Blythe, Ann E., Niemi, Nathan A., Bank, Gregory C., Barth, Andrew, Spotila, James A., House, Martha A., Blythe, Ann E., Niemi, Nathan A., and Bank, Gregory C.

Abstract

We have investigated what controls geomorphic evolution of active mountain belts by comparing the patterns of erosion in the San Gabriel and San Bernardino Mountains of southern California. These siblings in the Central Transverse Ranges are juxtaposed across the San Andreas fault and have been tectonically uplifted since the late Miocene under roughly similar conditions, yet their geomorphic expressions are very different. Because these ranges share numerous boundary conditions and because their syn-uplift exhumation is constrained by thermochronometric and geologic data, they provide a template to explore the role of specific parameters on the erosion of mountains. To address this, existing constraints on long-term exhumation are synthesized and used to construct best-guess models of erosion patterns in each range. These patterns of erosion are then compared to variables that are generally considered to be important influences on erosion rate. Erosion rate is correlated with topographic slope, suggesting that the two are coupled and that the questions of what controls erosion and what controls topography are interchangeable. Erosion patterns are also strongly influenced by the distribution of active structures, suggesting that deformation alone may be responsible for the observed patterns within each range. However, additional correlations with erosion exist in bedrock erodibility and mean annual precipitation. Altogether, broad differences between the two ranges may be explained by either structure, bedrock erodibility, long-term precipitation, or the greater duration of uplift of the San Gabriel Mountains. All of the boundary conditions that are generally considered important in the erosion of mountains are thus found to be related to erosion patterns in the Central Transverse Ranges. Without a means to isolate the relative influence of each parameters, however, we conclude that geomorphic differences between the ranges are the result of coincidental spatial arr

Published
2002

271. Low-temperature thermochronology of the San Gabriel and San Bernardino Mountains, southern California: Constraining structural evolution

Author

Barth, Andrew, Blythe, Ann E., House, Martha A., Spotila, James A., Barth, Andrew, Blythe, Ann E., House, Martha A., and Spotila, James A.

Abstract

Recently, apatite fission-track and (U-Th)/He analyses have been used to constrain the low temperature thermal history of the San Gabriel and San Bernardino Mountains of the central Transverse Ranges of southern California. In this paper, we use these data to estimate the timing of initiation of exhumation (uplift and erosion) on fault blocks within both ranges. We calculate average exhumation rates for different time intervals and reconstruct the evolution of both ranges and adjacent fault blocks over the past 12 m.y. using the Matti and Morton (1993) reconstructions as a base. With these reconstructions we are able to evaluate the variations in response (indicated by exhumation rate) to tectonic forces as the San Gabriel Mountains moved past the San Bernardino Mountains. In general, the San Bernardino Mountains have a much simpler exhumational and structural history than the San Gabriel Mountains, with the most recent phase of exhumation and uplift of geomorphic surfaces beginning ca. 2.5 Ma. This time is long after the most recent phases of exhumation began on fault blocks within the San Gabriel Mountains. There, distinct variations in fault-block exhumation patterns began ca. 12 Ma, when the southern strand of the San Gabriel fault became active. We conclude that although some similarities in exhumational history between the two ranges are evident beginning ca. 3-2.5 Ma, the differences in exhumational patterns between the two ranges indicate that they are not reacting similarly to regional tectonic stresses. The exhumational patterns observed suggest that the San Jacinto Mountains-Peninsular Ranges province is acting as an indentor, controlling when faults have turned on and off and the loci of highest exhumation rates.

Published
2002

277. Persistent Leatherback Turtle Migrations Present Opportunities for Conservation

Author

Shillinger, George L, primary, Palacios, Daniel M, additional, Bailey, Helen, additional, Bograd, Steven J, additional, Swithenbank, Alan M, additional, Gaspar, Philippe, additional, Wallace, Bryan P, additional, Spotila, James R, additional, Paladino, Frank V, additional, Piedra, Rotney, additional, Eckert, Scott A, additional, and Block, Barbara A, additional

Published
2008
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283. Respiration in neonate sea turtles

Author

Price, Edwin R., primary, Paladino, Frank V., additional, Strohl, Kingman P., additional, Santidrián T., Pilar, additional, Klann, Kenneth, additional, and Spotila, James R., additional

Published
2007
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285. Nesting ecology of East Pacific green turtles at Playa Cabuyal, Gulf of Papagayo, Costa Rica.

Author

Santidrián Tomillo, Pilar, Roberts, Spencer A., Hernández, Ricardo, Spotila, James R., and Paladino, Frank V.

Subjects
NEST building, PACIFIC green turtle, TURTLE nests, TURTLE populations, GREEN turtle, GULF of Papagayo (Costa Rica), REPRODUCTION
Abstract

East Pacific green turtles ( Chelonia mydas), often referred to as black turtles, are smaller and exhibit a lower reproductive output than other populations of green turtles in the Atlantic, Indian and Western Pacific Oceans. Knowledge of nesting ecology of East Pacific green turtles is limited to general descriptions. We conducted an exhaustive analysis of the nesting ecology of East Pacific green turtles at Playa Cabuyal, North Pacific Costa Rica. Compared with other populations of green turtles, East Pacific turtles exhibited smaller clutch sizes (mean ± SD: 76.9 ± 18.2 eggs per clutch), but the number of clutches (estimated clutch frequency ( ECF): 4.3 ± 2.3 clutches) fell within the upper limit reported for green turtles. Clutch size and seasonal reproductive output (409 ± 135 eggs per female), but not ECF, increased with female size. The observed internesting period ( OIP) between consecutive oviposition events (mean ± SD: 15.4 ± 2.9 days) increased as the season progressed and was approximately 2 days longer than the mean OIP reported for the species. Most clutches were laid in the upper vegetated part of beach (zone 3, 75%) and within this zone, tended to be located underneath trees (79%). Hatching success of clutches laid underneath trees was significantly higher (0.89 ± 0.17) than that of clutches laid in the exposed areas of zone 3 (0.75 ± 0.33). Mean duration of the nesting process (3:14 h) was on average 45 min longer than previously reported for the species. Frequency of false crawls was high (49% of nesting activities), and nesting success was low (54% of nesting attempts). Poaching of eggs, tourism and predation by dogs were important threats to this population. Conservation actions were being successfully implemented at the local level due to presence of beach patrollers, but official protection is needed for the preservation of the nesting population into the future. [ABSTRACT FROM AUTHOR]

Published
2015
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286. Between the bay and a hard place: Altered diamondback terrapin nesting movements demonstrate the effects of coastal barriers upon estuarine wildlife.

Author

Winters, Julianne M., Avery, Harold W., Standora, Edward A., and Spotila, James R.

Subjects
DIAMONDBACK terrapin, NEST building, REPTILE migration, ESTUARINE animals, TURTLE ecology, COASTAL ecology
Abstract

ABSTRACT Human development can impede wildlife moving between complementary habitats, particularly in highly disturbed coastal ecosystems. Coastal barriers may affect the behavior of diamondback terrapins ( Malaclemys terrapin), a salt-tolerant estuarine turtle that requires access to complementary upland habitat for annual nesting. We used telemetry to quantify terrestrial and aquatic movements of 78 nesting female terrapins in response to coastal barriers at 2 sites in Barnegat Bay, New Jersey, a heavily developed estuary. Nesting female terrapins traveled significantly greater distances with more tortuous paths or spent significantly more time in the water when their movements were obstructed than females nesting at beaches with no obstructions. We hypothesize that the additional effort and displacement associated with reproduction where obstructions exist will reduce terrapin fitness and potentially contribute to population declines. Our study demonstrates a unique approach to quantifying effects of barriers on organisms requiring complementary habitats, and improves our understanding of the impacts of shoreline hardening on estuarine wildlife threatened by encroaching coastal development. © 2015 The Wildlife Society. [ABSTRACT FROM AUTHOR]

Published
2015
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287. Spatial Ecology of Northern Pinesnakes ( Pituophis m. melanoleucus) in Disturbed and Undisturbed Habitats in the New Jersey Pine Barrens.

Author

Smith, Ronald M., Spotila, James R., and Bien, Walter F.

Subjects
*PINE snake, *SPATIAL ecology, *HABITATS, *PINE barrens, *RADIO telemetry, *ANIMAL populations, *ANIMAL behavior
Abstract

The decline in snake populations has been attributed primarily to anthropogenic disturbances, including habitat destruction and fragmentation. We radio-tracked Northern Pinesnakes ( Pituophis m. melanoleucus) in a military Target Zone and in the surrounding undisturbed buffer zone at the Warren Grove Gunnery Range in the New Jersey Pine Barrens, USA, to examine differences in spatial movement patterns and behavior. There were no differences in home range size ( X¯ = 60.0 ± 32.7 ha), core activity area ( X¯ = 10.6 ± 8.2 ha), range length ( X¯ = 1294.8 ± 32.7 m), or mean distance traveled per day ( X¯ = 65.2 ± 30.1 m) across all snakes, or between sexes (male n = 13, female n = 11), or location within ( n = 13) or outside ( n = 11) of the Target Zone. However, there were differences between tracking years. Northern Pinesnakes in 2005 and 2006 ( n = 13) traveled greater total distance and mean distance per day and had larger home ranges compared to snakes radio-tracked in 2003 and 2004 ( n = 11). In 2005 and 2006, snakes in the Target Zone traveled longer distances compared to snakes outside the Target Zone. Pinesnakes used both the Target Zone and undisturbed buffer zone for mating, nesting, foraging, and hibernating. Although the Target Zone was disturbed regularly, the open-canopied landscape, cover availability, and sandy soils maintained habitat for Northern Pinesnakes. Our data indicate that the military disturbance had little impact on the spatial ecology of Northern Pinesnakes; the disturbed area supported enough natural habitat features used by Northern Pinesnakes and was surrounded by a large tract of undisturbed landscape. These data can aid in developing mitigation and conservation strategies where the habitat of Northern Pinesnakes is threatened by development, in particular, across other military installations, which commonly overlap with the occurance of Northern Pinesnakes. [ABSTRACT FROM AUTHOR]

Published
2015
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