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Bodega Bay, Fort Bragg, and Eureka. Based on a time-series analysis at different latitudinal sites, we predict that megalopae-settler landings at the four sites will exhibit spatial dependence in their relationship to local environmental processes. Results will be used by the California Department of Fish and Wildlife to assess latitudinal variations in recruitment and to inform M. magister fishery management for the 2013/14 season.
MORPHOLOGICAL CHARACTERIZATION OF SOUTHERN CALIFORNIA PIPEFISH (FAMILY SYNGNATHIDAE)Cristy Rice, Kristy Forsgren.
California State University, Fullerton, Fullerton, CA.
Many teleost fish populations, such as the pipefishes (family Syngnathidae) are dependent on seagrass beds for all or part of their life cycle. Many pipefish species are morphologically similar, which makes identification extremely challenging in the field. Additionally, the only dichotomous key available for species identification, developed in 1972, does not include all species found along the California coast. We hypothesize that external morphological characteristics and measurements can be used to positively identify pipefish species. The specific objectives of this study are to survey California seagrass beds to gain a better understanding of species presence and distribution and establish morphological characteristics to accurately identify and differentiate between pipefish species. Preliminary data were collected on three pipefish species: bay pipefish, Syngnathus leptorhynchus (n = 24); kelp pipefish, Syngnathus californiensis (n = 30); and snubnose pipefish, Cosmocampus arctus (n = 4). This data indicated that the head-length to snout-width ratio is significantly different (p 0.0001) among all species. Additionally, the bay pipefish has two dark spots at the base of the operculum, the kelp pipefish has the longest snout examined thus far, and the snubnose pipefish has a truncated snout. In order to conclusively characterize pipefish species, future work will focus on collecting additional pipefishes from multiple locations and developing molecular fingerprints for each species that can be positively correlated with morphological characteristics. The results from this study will be used to update the Miller and Lea dichotomous key, which will be beneficial to fishery biologists in the field by aiding the quick and accurate identification of California pipefishes.
RATTLESNAKE ENCOUNTERS ALTER VIGILANCE BEHAVIOR OF THE CALIFORNIA GROUND SQUIRRELRey Ayon, Rulon Clark.
San Diego State University, San Diego, CA.
In the California ground squirrel (Otospermophilus beecheyi), evolutionary persistence theory is used to explain stereotyped responses towards their primary predator, the northern pacific rattlesnake (Crotalus oreganus). At the onset of snake recognition, ground squirrels comprising virtually every extent of phylogenetic sympatry with rattlesnakes invariably respond with elongated postures, close-range inspection, and communicative displays such as tail flags. After an encounter, squirrels readily treat their environment, particularly the snake’s location, with elevated caution. This heightened vigilant state may last even after the snake abandons its ambush site, evidently as a snake-induced wariness of potential predators in the area. However, insufficient evidence exists to demonstrate the efficacy of heightened vigilance in identifying predators during subsequent environmental interactions. If squirrels that
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encounter rattlesnakes maintain elevated vigilance, they should increase antisnake behavior toward even nonsnake objects in the area. Adult ground squirrels from the Diablo Mountain range in San Jose, California, were shown live northern pacific rattlesnakes, plaster rattlesnake models, and novel objects. We quantitatively described degrees of vigilance as indicated by antisnake behavior during natural field interactions. Rattlesnakes significantly increased ground squirrel vigilance behavior compared to snake models and novel objects. Only squirrels that had previously interacted with a rattlesnake exhibited significantly higher responses towards novel objects. Additionally, the response to snake models and novelties after rattlesnake encounters was only marginally lower than responses to rattlesnakes alone. These results demonstrate that ground squirrels can generalize their vigilance behavior throughout the vicinity of a snake encounter, possibly functioning to decrease the latency in discovering nearby predators.
DEVELOPING A SEED COLLECTION METHOD FOR LONG-TERM STORAGE AND TESTING VIABILITY OF THE
FEDERALLY ENDANGERED PLANT ERIASTRUM DENSIFOLIUM SPP SANCTORUMIgnacio Vera, Darren Sandquist.
California State University, Fullerton, Fullerton, CA.
The Santa Ana River woolly star, Eriastrum densifolium spp. sanctorum, is a federally listed, endangered plant species native to the Santa Ana River floodplain in Redlands, California. A major cause for its protection is the lack of occasional flooding from the Santa Ana River due to regional flood control measures. The woolly star has a specific habitat preference for sand deposits near rivers that experience flooding every few years. This habitat type is limited and only supports small populations of woolly stars. The goals of this project were to develop a consistent seed collection protocol and to collect seeds for long-term storage and woolly star habitat mitigation. Seeds were collected from 4 field sites in San Bernardino County, California and filtered through a series of sieves (No.14 and No. 25 standard soil sieves) to minimize the debris retained and maximize seeds recovered within a sample. Seedto-mass regressions were created by weighing subsamples across five increments between approximately 0.1 - 0.2 g (up to 0.9 g) and manually counting the number of visibly potentially viable seeds within each sample. These regressions were used to estimate the amount of potentially viable seeds collected for each site. Weekly collections from September 13 to November 4, 2012, amassed 57,000 seeds. Across sites, there was some variability among the regressions’ slopes (mass to viable seeds ratio) that is not clearly understood, suggesting more testing may be necessary. This method produced 47% to 79% successfully viable seeds with an average of 62% with only 87.5 manhours total.
TANAGERS AND AVIAN MALARIA: ARE FEMALES DIFFERENTIALLY SUSCEPTIBLE IN DIMORPHIC SPECIESIris Olivas1, Christopher Witt2.
University of New Mexico, Albuquerque, NM, 2Museum of Southwestern Biology, University of New Mexico, 1 Albuquerque, NM.
Avian malaria parasites (Haemosporidia) are widespread, common, and diverse. However, almost nothing is known about avian malaria in the Amazon and the Andes where the world’s most diverse bird communities occur. We surveyed birds for avian malaria throughout several seasons from 2007 to 2010. Birds were surveyed across a steep elevation gradient at different sites, and blood smears were collected. The blood smears were screened for malaria parasites (Parahaemoproteus and Plasmodium) by microscopy. Higher infection rates were found to correlate with the breeding season later in the year. As of yet, it is unknown whether females are more susceptible to infections due to being more involved in parental care than males in dimorphic species. Infected females may serve as malaria reservoirs to nestlings.
INTERSPECIFIC COMPETITION AND SOCIAL HIERARCHIES IN FRUGIVOROUS NEOTROPICAL BIRDS OFCOSTA RICA Brittany Thornton1, Jessie Knowlton2, Wendy Kuntz3.
University of Colorado, Boulder, Boulder, CO, 2Organization for Tropical Studies, Las Cruces, CR, 3Kapiolani 1 Community College, Honolulu, HI.
Dominance hierarchies have long been observed in nature across many different species. Through agonistic behaviors, animals are able to compete for resources while minimizing their physical conflict and energy expense.
Understanding of these interactions is important in determining which factors contribute to community structure.
Costa Rica is home to a plethora of bird species, about 400 of which are found at Las Cruces Biological Station, our study site. The object of this study was to examine which frugivorous Neotropical birds are dominant in interspecific interactions at feeding stations, and whether elements such as diet or size influenced their relative success in gaining the best access to resources. We predicted that birds with a higher weight would be more dominant and thus more successful in obtaining greater access during interspecific resource partitioning. To test our hypothesis, we observed 10 feeding stations spaced at least 50 m apart in garden habitat, where we observed and recorded dominance patterns. The feeding stations were baited with a banana and were placed within 50 cm of escape vegetation, in order to provide cover from predators. In addition to recording all aggressive and supplanting behaviors we recorded species, diet, body weight (g) and body length (cm). Preliminary data suggests that weight is an important factor in influencing success in the social hierarchies of frugivorous Neotropical birds. This result suggests that size may create a linear dominance pattern, which can provide insight into which species will be most threatened as resources become more scarce.
DIFFERENTIAL DEFENSE OF MALE AND FEMALE CECROPIA OBTUSIFOLIA TREESMotusaga Vaeoso1, Cynthia Sagers2.
Chaminade University of Honolulu, Honolulu, HI, 2University of Arkansas, Fayetteville, AR.
1 Decisions about resource allocation may differ among sexes when males and females invest unequally in their offspring. Typically, females invest more in each offspring than males, particularly in plants where females invest in fruits and seeds, whereas males invest only in pollen. Cecropia is a neotropical genus of tree comprised of approximately 60 species, all of which are dioecious. Flowers of both sexes are small but female fruits are much larger than male inflorescence. The purpose of this study is to examine resource allocation to defense in Cecropia obtusifolia. The expectation is that the females will defend their investment at a higher level than males. Research was conducted at the Las Cruces Biological Station, Coto Brus County, Costa Rica. Leaves of C. obtusifolia were collected and a suite of defensive characteristics were measured, including trichome density, leaf toughness, ant species present, trichilium area, and herbivory of sexually mature plants. Results of this study will be presented and the implications discussed. This project will provide new insights in the understanding of resource allocation and evolution of plant phenotypes.
THE IMPACT OF DESERT ROADS ON PLANT GROWTH AND SUBSEQUENT EFFECTS ON ANIMAL
DISTRIBUTIONAlexis Bueno Correa, Emily Sanchez, Frank Campos, Velvet L. Park, Matthew Scanlon, William Hoese, Christopher Tracy.
California State University, Fullerton, Fullerton, CA.
Water runoff from desert roads can increase roadside plant growth. Increased plant resources attract animals to roadsides, but cars on these roads pose additional risks that may vary among species with different life histories.
Negative effects of roads tend to be greater for vagile, long-lived species. Thus desert roads could alter distributions of animal populations. We investigated whether the density and volume of creosote bushes (Larrea tridentata) and the number of desert tortoise (Gopherus aggassizii) and desert rabbit (Sylvilagus audubonii and Lepus californicus) signs differed between 0 m and 400 m from Kelbaker Road in the Mojave National Preserve, California. We hypothesized that creosote bush density and volume and the number of rabbit signs would be lower and the number of desert tortoise signs would be higher at 400 m than at 0 m from the road. We used transects to survey animal signs and
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quadrats to sample rabbit scat and bushes. Creosote bush volume was significantly greater near the road, while bush density was not significantly different. There was no significant difference in desert tortoise signs, rabbit signs, or rabbit scat abundance between the two distances. The abundance of rabbit signs was negatively correlated with creosote bush density and positively correlated with creosote bush volume. Because our results do not agree with those of similar studies, they suggest that the impact of desert roads may depend on road-specific characteristics such as traffic volume or road orientation within landscapes and emphasize the importance of recognizing variation among road effects for conservation efforts.
BEHAVIORAL PATTERNS OF DIFFERENT SPECIES OF HUMMINGBIRDS (TROCHILIDAE) IN TEMPORAL
NICHES WHILE MANIPULATING HELICONIA TORTUOSA NECTAR CONCENTRATIONShaina Dixon1, Wendy Kuntz2.
University of Wisconsin-Stevens Point, Stevens Point, WI, 2Kapiolani Community College, Honolulu, HI.
1 Resource partitioning defines how species coexist with each other in the various niches available. Physical traits, such as bill length in hummingbirds, are widely examined but may not be the only influence on how organisms coexist. Behavioral traits, such as time of daily feeding, can also be mechanisms for resource partitioning. Las Cruces Biological Field Station, Costa Rica is home to over 30 species of hummingbirds and presents an opportunity to investigate if the temporal niches are important in resource partitioning in this species complex. We hypothesized that the smaller Rufous-tailed Hummingbird (Amazilia tzacatl) would occupy Heliconia tortuosa patches during early morning hours. Then, during the mid to late morning, the larger Green Hermit (Phaethornis guy) would displace A.