Ecology and Evolutionary Biology Commons^™

The Kin Composition Of Social Groups: Trading Group Size For Degree Of Altruism, Leticia Avilés, Jeffrey Alan Fletcher, Asher D. Cutter

Systems Science Faculty Publications and Presentations

Why some social systems form groups composed of kin, while others do not, has gone largely untreated in the literature. Using an individual-based simulation model, we explore the demographic consequences of making kinship a criterion in group formation. We find that systems where social groups consist of one generation breeding associations may face a serious trade-off between degree of altruism and group size that is largely mediated by their kin composition. On the one hand, restricting groups to close kin allows the evolution of highly altruistic behaviors but may limit group size to suboptimal levels, the more severely so the …

Projecting Range Expansion Of Invasive European Green Crabs (Carcinus Maenas) To Alaska: Temperature And Salinity Tolerance Of Larvae, Anson Hines, Greg Ruiz, Natasha Gray Hitchcock, Catherine E. De Rivera

Environmental Science and Management Faculty Publications and Presentations

The European Green Crab (Carcinus maenas) is a global invader, successfully colonizing many world regions and having significant ecological and economic impacts. The Green Crab colonized western North America in the late 1980s, spreading primarily northward from the initial establishment in San Francisco Bay to several other bays in northern California, Oregon, and Washington. Initial analysis, based largely upon temperature tolerance of postlarval crabs, suggests Green Crabs will continue to spread and become established throughout much of Alaska. However, establishment of self-sustaining populations in Alaska may be restricted by environmental conditions for reproduction and larval development, instead of the broad …

Relationships Between Needle Nitrogen Concentration And Photosynthetic Responses Of Douglas-Fir Seedlings To Elevated Co2 And Temperature, James D. Lewis, Melissa S. Lucash, David M. Olszyk, David T. Tingey

Environmental Science and Management Faculty Publications and Presentations

• Here we examined correlations between needle nitrogen concentration ([N]) and photosynthetic responses of Douglas-fir (Pseudotsuga menziesii) seedlings to growth in elevated temperatures and atmospheric carbon dioxide concentrations ([CO₂]).
• Seedlings were grown in sunlit, climate-controlled chambers at ambient or ambient+3.5^° C and ambient or ambient +180 μmol mol^-1 CO₂ in a full factorial design. Photosynthetic parameters and needle [N] were measured six times over a 21-month period.
• Needle [N] varied seasonally, and accounted for 30–50% of the variation in photosynthetic parameters. Across measurement periods, elevated temperature increased needle [N] by 26% and light-saturated …