Publications

@article{Link2014,

title = {Species differences in the seasonality of evergreen tree transpiration in a Mediterranean climate: Analysis of multiyear, half-hourly sap flow observations},

author = {Percy Link and Kevin Simonin and Holly Maness and Jasper Oshun and Todd Dawson and Inez Fung},

url = {https://angelo.berkeley.edu/wp-content/uploads/sites/59/Link_2014_WaterResoRese.pdf},

doi = {10.1002/2013WR014023},

year  = {2014},

date = {2014-03-01},

urldate = {2014-03-01},

journal = {Water Resources Research},

volume = {50},

number = {3},

pages = {1869-1894},

abstract = {In Mediterranean climates, the season of water availability (winter) is out of phase with the season of light availability and atmospheric moisture demand (summer). We investigate the seasonality of evergreen tree transpiration in a Mediterranean climate, using observations from a small (4000 m2), forested, steep (32°) hillslope, in the northern California Coast Range. We analyze 3 years of half-hourly measurements from 39 sap flow sensors in 26 trees, six depth profiles of soil moisture measured by TDR, and spatially distributed measurements of micrometeorology from five locations. The sap flow measurements show that two common evergreen tree species have different seasons of peak transpiration. Douglas-firs (Pseudotsuga menziesii) maintain significant transpiration through the winter rainy season and transpire maximally in the spring, followed by a sharp decline in transpiration in the summer dry season. Pacific madrones (Arbutus menziesii), and to a lesser extent other broadleaf evergreen species (Quercus wislizeni, Notholithocarpus densiflorus, Umbellularia californica), in contrast, transpire maximally in the summer dry season. The seasonal patterns are quantified using principal component analysis. Markov chain Monte Carlo estimation of response to environmental variables shows that the difference in transpiration seasonality arises from different sensitivities to atmospheric evaporative demand and root-zone moisture. The different sensitivities to atmospheric evaporative demand also create species differences in transpiration variability at synoptic time scales. Using the sap flow measurements and a regional forest inventory, a bottom-up regional transpiration estimate is constructed. The estimate suggests that sensitivity of Douglas-fir transpiration to water stress suppresses dry season evapotranspiration at the regional scale.},

keywords = {ERCZO, sap flow, seasonality, transpiration},

pubstate = {published},

tppubtype = {article}

}

@article{Power2013,

title = {Food webs in Mediterranean rivers},

author = {Mary E. Power and Joseph R. Holomuzki and Rex L. Lowe},

url = {https://angelo.berkeley.edu/wp-content/uploads/sites/59/Power_2013_Hydrobio.pdf},

doi = {10.1007/s10750-013-1510-0},

year  = {2013},

date = {2013-05-28},

journal = {Hydrobiologia},

volume = {719},

number = {1},

pages = {119-136},

abstract = {River food webs are subject to two regimes of longitudinally varying ecological control: productivity and disturbance. Light-limited productivity increases as channels widen downstream. Time windows for growth, however, shrink as discharge increases, substrate particle size decreases, and the frequency of flood-driven bed mobilization increases downstream. Mediterranean rivers are periodically reset by hydrologic events with somewhat predictable timing. Typically, a rainy winter with high river discharge is followed by summer drought with little or no rainfall and slowly declining river flow. The magnitude and timing of winter floods and severity of subsequent summer drought can vary considerably from year to year, however. Episodic scouring floods or prolonged periods of drought are experienced as disturbances, stressors, or opportunities by river biota. The timing, duration, and intensity of these hydrologic controls affect performances of individuals, distribution and abundances of populations, and outcomes and consequences of species interactions. These interactions in turn determine how river food webs will assemble, develop, and reconfigure after disturbance. We discuss how spatial variation in solar radiation and spatial and temporal variations in disturbance affects river food webs under Mediterranean climate seasonality, focusing primarily on long-term observations in the Eel River of northwestern California, USA},

keywords = {Algal production, Cross-ecosystem fluxes, Detritus Disturbance, Drought, fate Carbon sources, Floods, Food quality, food webs, hydrology, Insect emergence, interaction strength, Mediterranean rivers, River-to-ocean fluxes, seasonality},

pubstate = {published},

tppubtype = {article}

}