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Full-Text Articles in Biology

Solidago Gigantea Plants From Nonnative Ranges Compensate More In Response To Damage Than Plants From The Native Range, Huixuan Liao, Priscila Gurgel, Robert Pal, Ragan Callaway Jan 2016

Solidago Gigantea Plants From Nonnative Ranges Compensate More In Response To Damage Than Plants From The Native Range, Huixuan Liao, Priscila Gurgel, Robert Pal, Ragan Callaway

Biological Sciences

Resistance and tolerance are two ways that plants cope with herbivory. Tolerance, the ability of a plant to regrow or reproduce after being consumed, has been studied less than resistance, but this trait varies widely among species and has considerable potential to affect the ecology of plant species. One particular aspect of tolerance, compensatory responses, can evolve rapidly in plant species; providing insight into interactions between consumers and plants. However, compensation by invasive species has rarely been explored. We compared compensatory responses to the effects of simulated herbivory expressed by plants from seven Solidago gigantea populations from the native North …


Census And Mapping Of Chorro Creek Bog Thistle In Reservoir Canyon, San Luis Obispo, Ca, Tyler Michael Lutz Dec 2013

Census And Mapping Of Chorro Creek Bog Thistle In Reservoir Canyon, San Luis Obispo, Ca, Tyler Michael Lutz

Biological Sciences

Chorro Creek bog thistle (Cirsium fontinale var. obispoense) is a federally endangered variety of Fountain thistle endemic to western San Luis Obispo County. The U.S. Fish and Wildlife Service knows of nineteen populations, many with multiple colonies. A population was discovered in the Reservoir Canyon Natural Reserve in 2001, but has not been monitored or described since the time of its discovery. In fall of 2013, a census of the population was performed, the four colonies were mapped, and a floristic survey was conducted. A field experiment was initiated to determine if reducing the riparian canopy coverage can …


The Spatial Games: Investigating The Spatial Distribution Of Anax And Select Prey As A Function Of Predator-Prey Interactions, Shane Elizabeth Johnson, Nene Kumashe Ugbah Jun 2012

The Spatial Games: Investigating The Spatial Distribution Of Anax And Select Prey As A Function Of Predator-Prey Interactions, Shane Elizabeth Johnson, Nene Kumashe Ugbah

Biological Sciences

Our study investigated the spatial distribution and movement behavior of predatory dragonfly larvae (Anax) and of two prey types: mosquito larvae and amphipods. Predator-prey interactions have important consequences for the population dynamics of both predator and prey groups and these interactions can shape community structure. We measured behavior of each prey type in the presence of the Anax predator and the behavior of the predator in the presence of these alternative prey types. Observations were made in five-gallon aquaria where a grid pattern allowed us to track the number of moves made by individuals. We compiled data from …


The Relationship Between 11-Ketotestosterone, Cortisol, And Testosterone And Condition Index For Poecilia Reticulata, Shelly Gupta, Brandy G. Kalbach Mar 2011

The Relationship Between 11-Ketotestosterone, Cortisol, And Testosterone And Condition Index For Poecilia Reticulata, Shelly Gupta, Brandy G. Kalbach

Biological Sciences

The guppy, Poecilia reticulata, is a common study organism for behavioral and other ecological experiments (Houde, 1997). As far as we know, no previous data have been compiled regarding hormones and condition index of guppies. In this experiment we examined the relationship between circulating levels of three hormones (testosterone, 11-ketotestosterone and cortisol) and condition index in males and also made comparisons among the hormone levels, for three guppy sites from the northern range of Trinidad – Aripo River, Marianne River and Small Crayfish River. Hormone samples were obtained using non-invasive water borne techniques and quantified by our collaborator. The condition …


Escape From Competition: Neighbors Reduce Centaurea Stoebe Performance At Home But Not Away, Ragan Callaway, Lauren Waller, Alecu Diaconu, Robert Pal, Alexandra Collins, Heinz Mueller-Schaerer, John Maron Jan 2011

Escape From Competition: Neighbors Reduce Centaurea Stoebe Performance At Home But Not Away, Ragan Callaway, Lauren Waller, Alecu Diaconu, Robert Pal, Alexandra Collins, Heinz Mueller-Schaerer, John Maron

Biological Sciences

The greater abundance of some exotic plants in their nonnative ranges might be explained in part by biogeographic differences in the strength of competition, but these competitive effects have not been experimentally examined in the field. We compared the effects of neighbors on the growth and reproduction of spotted knapweed (Centaurea stoebe) in Europe, where it is native, and in Montana, where it is invasive. There were strong negative competitive effects of neighboring vegetation on C. stoebe growth and reproduction in Europe. In contrast, identical experiments in Montana resulted in insignificant impacts on C. stoebe. Although the mechanisms that produce …