biology join - Coweeta LTER - University of Georgia

More documents

Recommendations

Info

Annual precipitation (mm) 4000 3500 3000 2500 2000 1500 1000 500 a 0 −15.0 −10.0 −5.0 0.0 5.0 10.0 15.0 20.0 25.0 Minimum daily temperature (°C) 1950 est 1960 est 1970 est 1980 est 1990 est 2010 est (NTL, for which the record began in 1990). Mean annual precipitation increased significantly at LUQ and NWT. The first day of spring (defined as the last day of freezing temperature) moved earlier by between 0.31 and 1.98 days per year—that is, by more than 15 days in 50 years—at eight sites (AND, ARC, CWT, FER, FRA, HBR, LUQ, MAR, NWT) (Hatcher 2011). Runoff ratios (Q:P) changed at 8 of 19 sites (figure 6b). Tundra and boreal forest sites with ice and permafrost (LVW, NWT) experienced increases in runoff ratios, and so did temperate deciduous forest sites in the northeastern United States (HBR, HFR, PIE), which have a seasonal snowpack. An increase in runoff ratio means either that AET has decreased, or that there is a net addition of water to the system, such as from melting ice or interbasin water transfers. The observed increases in runoff ratios at LVW and NWT may be associated with the melt of ice, snow, and permafrost in response to warming temperatures during seasons in which these ecosystems are dormant (not taking up water). However, warming did not result in increased runoff ratios at other sites with permafrost (ARC, which has a short record) or seasonal snowpacks (e.g., AND, FRA, MAR, NTL). Runoff Articles 1950 est 1960 est 1970 est 1980 est 1990 est 2010 est .1 0 A CAP −10.0 −5.0 0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 ratios did not change at most other sites, which mostly lack significant snow and ice (Hatcher 2011). Streamflow changes vary according to the season and differ among various biomes (figure 7). At undisturbed desert sites in Arizona (CAP) and New Mexico (SEV), streamflow did not change at any time of year (figure 7a, 7b). However, in a desert mountain basin northeast of JRN (New Mexico) and in a semiarid mountain basin near SBC (southern California) containing residential and urban development, streamflow increased during low-flow periods (figure 7c, 7d). In a large basin in coastal Georgia containing agriculture and forest plantations (GCE), streamflow declined in early and late summer (figure 7e). At tundra sites on the North Slope of Alaska and in the Rocky Mountains (ARC, NWT; figure 7f, 7g), streamflow increased in early spring and late fall, during time periods adjacent to freezing periods. Streamflow increased in spring at boreal forest sites in the Rocky Mountains (FRA, LVW; figure 7h, 7i). At a temperate forest site in western North Carolina (CWT), where seasonal snowpacks do not form, streamflow did not change at any time of year (figure 7j), but at a temperate forest site in West Virginia (FER), streamflow www.biosciencemag.org April 2012 / Vol. 62 No. 4 • BioScience 397 Runoff ratio (discharge:precipitation) 1 .9 .8 .7 .6 .5 .4 .3 .2 b Maximum daily temperature (°C) Figure 6. (a) Multidecade trends in minimum daily temperature (in degrees Celsius [°C]) and precipitation (in millimeters [mm]) at long-term watershed study sites. Each site is designated by the minimum daily temperature and precipitation at the beginning and end of the decades spanning the period of record, based on the statistically significant trend in that variable over the period of record. The initial observation is connected to or contained within the 2010 estimated (est) observation for each site. The radius of the 2010 estimated symbol is 0.5°C and 125 mm. Statistically significant increases in minimum daily temperature occurred at all sites except ARC, CAP, JRN, PIE, and SEV (the study-site characteristics and abbreviations are in supplemental table S1, available online at http://dx.doi. org/10.1525/bio.2012.62.4.10). Statistically significant changes in annual precipitation occurred only at LUQ and NWT. (b) Multidecade trends in maximum daily temperature and runoff ratios at long-term watershed study sites. Each site is designated by the maximum daily temperature and runoff ratio at the beginning and end of the decades spanning the period of record, based on the trend in that variable over the period of record. The initial observation is connected to or contained within the 2010 estimated observation for each site. The radius of the 2010 estimated symbol is 0.5°C and .0125. Statistically significant increases in maximum daily temperature occurred at CAP, FRA, JRN, LUQ, NWT, and SEV. Statistically significant changes in annual streamflow occurred at FER, GCE, HFR, HBR, JRN, LVW, MAR, NWT, NTL, PIE, and SEV.
Articles Proportion change per year relative to the mean daily flow Proportion change per year relative to the mean daily flow Proportion change per year relative to the mean daily flow Proportion change per year relative to the mean daily flow Proportion change per year relative to the mean daily flow a b CAP – Sycamore Creek – 1961–2010 SEV – Jemez River – 1954–2010 .10 .015 .05 .00 .01 .005 .00 −.05 −.005 −.01 O N D J F M A M J J A S O −.01 O N D J F M A M J J A S O Month Month c JRN – Rio Ruidoso – 1950–2010 d SBC – San Jose Creek – 1950–2010 .015 .08 .01 .06 .005 .04 .00 .02 −.005 .00 −.01 −.02 −.015 O N D J F M A M J J A S O −.04 O N D J F M A M J J A S O Month Month e GCE – Ohoopee River – 1950–2009 f ARC – Kuparuk River – 1971–2010 .02 .20 .01 .15 .10 .00 .05 −.01 .00 −.05 −.02 −.10 −.03 O N D J F M A M J J A S O −.15 O N D J F M A M J J A S O Month Month g NWT – Green Lake 4 – 1981–2008 FRA – East Saint Louis – 1976–2005 .10 .04 .05 .03 .02 .00 .01 −.05 .00 −.01 −.10 −.02 −.15 O N D J F M A M J J A S O −.03 O N D J F M A M J J A S O Month Month i LVW – Loch Vale out let – 1984–2010 j CWT – WS18 – 1950–2009 .10 .015 .001 .05 .005 .00 .000 −.005 −.05 −.010 −.10 O N D J F M A M J J A S O −.015 O N D J F M A M J J A S O Month Month Figure 7. Daily changes in streamflow at 19 US Long Term Ecological Research sites, US Forest Service Experimental Forests and Ranges, and US Geological Survey Water, Energy, and Biogeochemical Budgets sites arranged by biome (from figure 4) as a function of the day of the water year (1 October to 30 September). (a–c) Desert sites (CAP, SEV, JRN); (d), (e) savanna sites (SBC, GCE); (f), (g) tundra sites (ARC, NWT); (h), (i) boreal forest sites (FRA, LVW); (j–p) temperate forest sites (CWT, FER, HFR, HBR, MAR, NTL, PIE); (q), (r) wet temperate forest sites (AND, OLY); (s) wet tropical forest site (LUQ). The vertical axis and the green line are the slope of regression of log-transformed streamflow for each day of the water year over the period of record (see supplemental table S1, available online at http://dx.doi.org/10.1525/ bio.2012.62.4.10). The vertical axis units are the proportion change per year relative to the mean daily flow. The percentage change can be calculated as (1 + p) n , where p is the proportion change and n is the number of years. Note the different vertical axis scales. The horizontal black line represents no change (a proportion change of 0); the wiggly black lines are the upper and lower bounds on the 97.5% confidence interval. The red dots represent significant increases, and the blue dots represent significant decreases in daily streamflow, where a � .025. 398 BioScience • April 2012 / Vol. 62 No. 4 www.biosciencemag.org Proportion change per year relative to the mean daily flow Proportion change per year relative to the mean daily flow Proportion change per year relative to the mean daily flow Proportion change per year relative to the mean daily flow Proportion change per year relative to the mean daily flow h
Page 1 and 2:
Articles Long-Term Ecological Resea
Page 3 and 4:
Articles 1992 BNZ AND HBR 2003 AND
Page 5 and 6: Articles challenges, a comprehensiv
Page 7 and 8: Articles LTER Network and many addi
Page 9 and 10: Articles Brook to interested audien
Page 11 and 12: Articles Points in Complex Environm
Page 13 and 14: Articles Science and Society: The R
Page 15 and 16: Articles Case studies in linking LT
Page 17 and 18: Articles land in the region from 36
Page 19 and 20: Articles to properly steward or inc
Page 21 and 22: Articles Ecoregions Subarctic tundr
Page 23 and 24: Articles present outputs such as th
Page 25 and 26: Articles Ray L. 2010. Can Community
Page 27 and 28: Articles and to define a range of p
Page 29 and 30: Articles Table 1. Features of the U
Page 31 and 32: Articles (Wiek et al. 2006, Withyco
Page 33 and 34: Articles and other societal respons
Page 35 and 36: Articles Shaw A, Sheppard S, Burch
Page 37 and 38: Articles Box 1. Definition of long-
Page 39 and 40: Articles Figure 1. Examples of the
Page 41 and 42: Articles Figure 3. Examples of long
Page 43 and 44: Articles legacies of pretreatment c
Page 45 and 46: Articles (Herbert et al. 1999). Mul
Page 47 and 48: Articles relevant to stakeholders i
Page 49 and 50: Articles Ecosystem Processes and Hu
Page 51 and 52: Articles natural disturbances and h
Page 53 and 54: Articles Figure 4. Mean annual temp
Page 55: Articles to climate oscillation var
Page 59 and 60: Articles (Min et al. 2011, Pall et
Page 61 and 62: Articles past land management and d
Page 63 and 64: Articles designed and manages the L
Page 65 and 66: Articles (Mazhitova et al. 2008), w
Page 67 and 68: Articles 1970s, widespread decrease
Page 69 and 70: Articles Figure 3. Duration of fros
Page 71 and 72: Articles depends on plant species.
Page 73 and 74: Articles Bowden WB, Gooseff MN, Bal
show all

biology join - Coweeta LTER - University of Georgia

Create successful ePaper yourself

Delete template?

Save as template?