00874nas a2200277 4500008004100000245012500041210006900166300001000235490000700245100002000252700002100272700002200293700002000315700001400335700002300349700001600372700001800388700001500406700001600421700001600437700001900453700001700472700001700489700001600506856007400522 2022 eng d00aN and P constrain C in ecosystems under climate change: role of nutrient redistribution, accumulation, and stoichiometry0 aN and P constrain C in ecosystems under climate change role of n ae26840 v321 aRastetter, E.B.1 aKwiakowski, B.L.1 aKicklighter, D.W.1 aPlotkin, Barker1 aGenet, H.1 aNippert, Jesse, B.1 aO'Keefe, K.1 aPerakis, S.R.1 aPorder, S.1 aRoley, S.S.1 aReuss, R.W.1 aThompson, J.R.1 aWieder, W.R.1 aWilcox, K.R.1 aYanai, R.D. uhttps://esajournals.onlinelibrary.wiley.com/doi/full/10.1002/eap.268402767nas a2200145 4500008004100000245005900041210005900100300001400159490000700173520230700180100001602487700002302503700001502526856008002541 2018 eng d00aDrivers of nocturnal water flux in a tallgrass prairie0 aDrivers of nocturnal water flux in a tallgrass prairie a1155-11670 v323 a

Nocturnal transpiration can impact water balance from the local community to earth‐atmosphere fluxes. However, the dynamics and drivers of nocturnal transpiration among coexisting plant functional groups in herbaceous ecosystems are unknown.
Here, we addressed the following questions: (1) How do nocturnal (Enight) and diurnal (Eday) transpiration vary among coexisting grasses, forbs, and shrubs in a tallgrass prairie? (2) What environmental variables drive Enight and do these differ from the drivers of Eday? (3) Is Enight associated with daytime physiological processes?
We measured diurnal and nocturnal leaf gas exchange on perennial grass, forb and woody species in a North American tallgrass prairie. Measurements were made periodically across two growing seasons (May–August 2014–2015) on three C4 grasses (Andropogon gerardii, Sorghastrum nutans and Panicum virgatum), two C3 forbs (Vernonia baldwinii and Solidago canadensis), one C3 sub‐shrub (Amorpha canescens) and two C3 shrubs (Cornus drummondii and Rhus glabra).
By extending our study to multiple functional groups, we were able to make several key observations: (1) Enight was variable among co‐occurring plant functional groups, with the highest rates occurring in C4 grasses, (2) Enight and Eday exhibited different responses to vapour pressure deficit and other environmental drivers, and (3) rates of Enight were strongly related to predawn leaf water potential for grasses and woody species, and were likely modulated by small‐scale changes in soil moisture availability.
Our results provide novel insight into an often‐overlooked portion of ecosystem water balance. Considering the high rates of Enight observed in C4 grasses, as well as the widespread global occurrence of C4 grasses, nocturnal water loss might constitute a greater proportion of global evapotranspiration than previously estimated. Additionally, future predictions of nocturnal water loss may be complicated by stomatal behaviour that differs between the day and at night. Finally, these data suggest a water‐use strategy by C4 grasses wherein the high rates of Enight occurring during wet periods may confer a competitive advantage to maximize resource consumption during periods of greater availability.

1 aO'Keefe, K.1 aNippert, Jesse, B.1 aSala, Anna uhttps://besjournals.onlinelibrary.wiley.com/doi/pdf/10.1111/1365-2435.1307202539nas a2200217 4500008004100000245010700041210006900148300001200217490000800229520184000237653001802077653002002095653001902115653002602134653001802160653002302178100001502201700001602216700002302232856006602255 2016 eng d00aComparative ecohydrology between Cornus drummondii and Solidago canadensis in upland tallgrass prairie0 aComparative ecohydrology between Cornus drummondii and Solidago  a267-2760 v2173 a

Woody species expansion threatens to transform mesic North American grasslands. In many tallgrass prairies of the central Great Plains with deep soil, Cornus drummondii develops large shrub islands that exhibit non-linear increases in cover through time. Reliance on soil moisture from deeper soil depths facilitates constant gas exchange rates and minimizes competition with coexisting herbaceous species. Conversely, C. drummondii growth and expansion in thin-soil locations is stochastic and these locations are typically free of large shrub islands. At the Konza Prairie in northeast Kansas, USA, we compared the ecohydrology of C. drummondii individuals to a similar-sized forb (Solidago canadensis) in thin-soil locations with varying fire frequency (4-, 20-year) and grazer abundance (bison present or absent). Gas exchange rates were relatively constant for C. drummondii, while S. canadensis declined across the growing season. For S. canadensis, maximum photosynthesis (Amax), daytime transpiration (E), and stomatal conductance (gs) were higher on ungrazed than grazed treatments. Nighttime E rates were higher in C. drummondii, accounting for over 10 % of the daytime E rates. The water source used did not vary among contrasts, with the majority of water uptake occurring from 30 cm depth for both species. These results highlight a unique ecohydrology of C. drummondii (static water flux, and high rates of nighttime E) compared to a similar-sized, co-occurring forb. Whereas C. drummondii is infrequent in thin-soil locations, the climate conditions occurring during measurements were not a likely filter restricting persistence. Rather, drier conditions or interactions with other grassland disturbances are likely required to restrict C. drummondii encroachment in the thins-soil locations of tallgrass prairie.

10aKonza Prairie10aMesic grassland10aphotosynthesis10aStable water isotopes10aTranspiration10awoody encroachment1 aMuench, A.1 aO'Keefe, K.1 aNippert, Jesse, B. uhttps://link.springer.com/article/10.1007%2Fs11258-016-0567-z00586nas a2200121 4500008004100000245012800041210006900169260004600238490001400284100001600298700002300314856012700337 2012 eng d00aInfluences of local adaptation and genome size on Panicum virgatum (switchgrass) responses to variable precipitation timing0 aInfluences of local adaptation and genome size on Panicum virgat aPhiladelphia, PAbSt. Joseph's University0 vMS Thesis1 aO'Keefe, K.1 aNippert, Jesse, B. uhttp://knz.lternet.edu/content/influences-local-adaptation-and-genome-size-panicum-virgatum-switchgrass-responses-variable