January 31 2019

5:00 pm 1100 TLSB

EcoEvoPub Series

Graduate Student Presentations


Daniel S. Cooper
Department of Ecology and Evolutionary Biology, UCLA

Title: Long-Term Patterns of Urban Tolerance in Nesting Raptors in the Malibu Creek Watershed of Southern California

Globally, many raptor species are treated as special-status species, while others are considered urban-tolerant at some scale, yet these assessments have changed through time. By identifying the least-tolerant species to urbanization, we can update priorities for conservation, and can direct greater conservation attention to those birds in greater need of protection and accommodation. We analyzed nest placement of 179 nests for six raptor speciesin the Malibu Creek Watershed of Los Angeles and Ventura counties (California) since 1971, generated an index of urban landuse surrounding each nest, and compared this with 100 randomly-generated points to identify changes in urban tolerance over time. Reconstructing a historical urban boundary, we estimate a three-fold increase of urbanized habitat and a doubling of the human population within the study area in the past fifty years. Two of the six species have since become extirpated as breeders here (Golden Eagle Aquila chrysaetosand White-tailed Kite Elanus leucurus). We document a strong recent shift toward urban sites for Coopers Hawk Accipiter cooperii, yet found no such bias over random sites for either Red-shouldered Hawk Buteo lineatusor Red-tailed Hawk B. jamaicensis. We identify American Kestrel Falco sparveriusas an urban avoider, found in significantly less urbanized areas than random points, with a strong preference for native (vs. non-native) nest tree species, a pattern reversed in the other remaining species. Our findings emphasize the importance of updating species conservation assessments as landscapes urbanize, as species either adapt to these changes or fail to do so.

Camila Medeiros
Department of Ecology and Evolutionary Biology, UCLA

Title: An Extensive Suite of Functional Traits Distinguishes Hawaiian Wet and Dry Forests and Enables Prediction of Species Vital Rates

The application of functional traits to predict and explain plant species distributions and vital rates has been a major direction in functional ecology for decades, yet numerous physiological traits have not yet been incorporated into the approach. Using commonly measured traits such as leaf mass per area (LMA) and wood density (WD), and additional traits related to water transport, gas exchange and resource economics, including leaf vein, stomatal, and wilting traits, we tested hypotheses for Hawaiian wet montane and lowland dry forests (MWF and LDF respectively): (1) forests would differ in a wide range of traits as expected from contrasting adaptation; (2) trait values would be more convergent among dry than wet forest species due to the stronger environmental filtering; (3) traits would be inter-correlated within modules supporting given function; (4) relative growth rate (RGR) and mortality rate (m) would correlate with a number of specific traits, with (5) stronger relationships when stratifying by tree size, and (6) RGR and m can be strongly explained from trait-based models. The MWF species traits were associated with adaptation to high soil moisture and nutrient supply and greater shade tolerance whereas the LDF species traits were associated with drought tolerance. Thus, on average, MWF species achieved higher maximum heights than LDF species and had leaves with larger epidermal cells, higher maximum stomatal conductance and CO2 assimilation rate, lower vein lengths per area, higher saturated water content and greater shrinkage when dry, lower dry matter content, higher phosphorus concentration, lower nitrogen to phosphorus ratio, high chlorophyll to nitrogen ratio, high carbon isotope discrimination, high stomatal conductance to nitrogen ratio, less negative turgor loss point, and lower WD. Functional traits were more variable in the MWF than LDF, were correlated within modules, and predicted species RGR and m across forests, with stronger relationships when stratifying by tree size. Models based on multiple traits predicted vital rates across forests (R2 = 0.70-0.72; P < 0.01). Our findings are consistent with a powerful role of broad suites of functional traits in contributing to forest species distributions, integrated plant design, and vital rates.

























































































































































































































































































































































































































































































































































































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