Limiting growth factors. Water Temperature Nutrients

Transcription

1 Limiting growth factors Water Temperature Nutrients

2 What are they? Nutrient Dynamics Why do we care? Stream chemistry study

3 Why do nutrients matter? Limit primary production Affect decomposition (+/ ) Shape biological diversity and ecological interactions Water pollution (P, N, Si)

4 Limit Primary Production Justus von Liebig: Law of the minimum ~1850: Growth is proportional to the amount of the most limiting nutrient, whichever nutrient it may be. Here in the Pacific Northwest, N is the limiting nutrient to growth (water is also a limiting factor to growth in the PNW) *courtesy Steve Perakis, USGS

5 Water Quality Concerns Between 70 and 80 percent of the water flowing in rivers in the U.S. originates as precipitation falling on forests The quality of water that flows from forests is generally among the best in the nation Nutrient concentrations in forested streams are usually less than 15 percent of levels found in streams that run through agricultural or urban areas The quality of water from forested streams is generally so high that a report by the Ecological Society of America on nonpoint pollution of surface waters with phosphorus and nitrogen did not even mention forests as areas of concern Dan Binkley, George G. Ice 2004

6 Sources of Nutrients Atmosphere Dry (gravity fallout) vs. Wet (deposition via precipitation) dust, ash, aerosols, precipitation N Biological N 2 fixation Weathering Climate, Biota, Topography, Parent Material, Time Fertilization P, S, Ca, Mg, K, Mo *courtesy Steve Perakis, USGS

7 Biological N 2 fixation Necessary to break the strong triple bond of N2 N2 is converted to ammonium, a biological form of nitrogen Bacteria with enzyme nitrogenase Found in the root nodules of some trees (red alder) Green algae in lichens Cyanobacteria

8 Constraints On Biological N 2 Fixation N fixation is energy intensive Nitrogenase is poisoned by O 2 Requires Mo, P, Fe, etc Herbivory of N rich tissues (rich in carbohydrates) Vitousek et al. 2002

9 Losses of Nutrients Atmosphere Hydrologic generally small, and nutrient specific (fire) solutes and suspended N, S Geologic Harvesting chemical occlusion (P) and erosion All nutrients *courtesy Steve Perakis, USGS

10 Fertilization Land managers employ the use of fertilization because of the ROI. Increased growth = more board feet. Fertilizer applied twice before harvest. This amounts to two applications over yrs. Global N Fertilizer Use Millions of tons/yr

11 Soil Nitrogen in the US cm

12 Algal blooms

13 Protect Riparian Areas Reduce nitrogen leaching Unfertilized riparian strips

14 Common Nutrients Element carbon, hydrogen, oxygen nitrogen (N) phosphorus (P) potassium (K) calcium (Ca) magnesium (Mg) sulfur (S) Principal function component of all organic molecules component of amino acids, proteins, chorophyll, nucleic acids component of ATP, NADP, nucleic acids, phopholipids ion/ osmotic balance, ph regulation, regulation of guard cell turgor cell wall strengthening and functioning, ionic balance, membrane permeability component of chlorophyll, enzyme activiation component of amino acids, proteins *courtesy Steve Perakis, USGS

15 Industrialized forests Increased demand for forest products Continually shrinking land base Concentration of timber production Industrialized forests = intensively managed timber plantations

16 Contemporary Forest Management Changes in forest management: The initiation of riparian management areas (RMA s) Road construction is almost a thing of the past Changes in methods of vegetation suppression Harvest regenerated secondgrowth trees

17 Hinkle Creek Paired Watershed Study Fill the gap of knowledge regarding the effect of contemporary forest practices on intensively managed forest land Address concerns about the loss of essential plant nutrients in Douglas fir plantations Assess the impacts of forest management on stream water chemistry of fish bearing streams

18 Hinkle Creek Paired Watershed Study The Hinkle Creek watershed is located in the Umpqua drainage of the Oregon Cascades, 18 km east of Sutherlin, OR Hinkle Creek

19 Hinkle Creek Paired Watershed Study Site Description: Almost 2,000 ha site Privately owned (Roseburg Forest Products) Managed entirely for timber production Harvest regenerated 60 year old Douglas fir stands Existing road structure

20 Hinkle Creek Paired Watershed Study Objectives: Determine the local impacts associated with non fish bearing streams Not afforded the protection of unharvested and unfertilized riparian strips Magnitude and duration of response relative to magnitude of disturbance

21 Hinkle Creek Paired Watershed Study Objectives: Determine the cumulative impacts to fishbearing streams Does the lack of protection for non fishbearing streams produce unacceptable downstream impacts to fish bearing streams?

22 Hinkle Creek Paired Watershed Study Objectives: Determine the local impacts to fish bearing streams Oregon Forest Practices Act requirements Local impacts vs. cumulative impacts

23 Hinkle Creek Paired Watershed Study Study design: Hinkle Creek is a paired, nested watershed study Two contiguous fish bearing watersheds served as a control and treatment Two non fish bearing headwater basins in the NF Four non fish bearing headwater basins in the SF Changes were monitored at two temporally and spatially explicit scales

24 Hinkle Creek Paired Watershed Study Gauging stations: Six headwaters outfitted with flumes and instrumentation The North and South Fork were outfitted with instrumentation but no flume Monitoring began in July of 2002 and ended in September of 2011

25 Hinkle Creek Paired Watershed Study 2001 treatment: Three clearcuts 11% of the watershed All were along non fish bearing streams

26 Hinkle Creek Paired Watershed Study treatments: Five clearcuts 14.3% of the watershed Fenton: 75% clearcut* Clay: 36% Russell: 15% BB: 32%** * Percent clearcut reflects the percentage of the basin ABOVE the gauging station only ** BB was considered 32% clearcut, not 52% clearcut

27 Hinkle Creek Paired Watershed Study treatments: Four clearcuts 12.2% of the watershed Un harvested riparian buffer strips were left along all fish bearing streams

28 Hinkle Creek Paired Watershed Study treatments: Four clearcuts 12.2% of the watershed Un harvested riparian buffer strips were left along all fish bearing streams

29 Stream water chemistry analysis Sampling locations: Sampling began in October 2002 at the eight gauged stations Three locations were added in January 2003

30 Stream water chemistry analysis Stream water chemistry: Samples were tested for concentrations of several nutrients, specific conductance, ph, and alkalinity Nutrients analyzed: organic and inorganic nitrogen Phosphorus (P) Sodium (Na) Calcium (Ca) Magnesium (Mg) Potassium (K) Sulfate (SO 4 ) Chloride (Cl) Silicon (Si)

31 Fertilization Fertilizer was applied to both watersheds in the fall of 2004 Existing clearcuts and imminent clearcuts did not receive fertilizer The North Fork received 25% more fertilizer per hectare Fish bearing streams: 60 foot buffer strips Non fish bearing streams: no protection Fenton received no fertilizer

32 Nutrient response results Most nutrients did not show an appreciable response to timber harvest Ammonia showed an increase in all watersheds Phosphorus did not display a response across watersheds Na, Ca, Mg, K, SO 4, Cl, Si, alkalinity and specific conductance showed a decrease across all watersheds greatest decreases observed in the treatment watersheds Nitrate showed the only statistically significant increase impact will refer to concentration of nitrate

33 Nitrate response Strong seasonal fluctuation during the calibration period

34 Nitrate response Strong seasonal fluctuation during the calibration period Muted seasonal response during the first post treatment period

35 Nitrate response Strong seasonal fluctuation during the calibration period Muted seasonal response during the first post treatment period More pronounced seasonal response during the second post treatment period

36 Nitrate response Nitrate concentrations in the North Fork exceed concentrations in the South Fork for the first time during the study

37 Nitrate response Concentrations in the South Fork during October 2009 were questionably high

38 Nitrate response Concentrations in the South Fork during October 2009 were questionably high Concentrations in the North Fork indicate something other than a treatment effect was responsible

39 Nitrate response Mean NO 3 + NO 2 (mg/l) Calibration Period 1 Period 2 North Fork South Fork Treatment headwaters

40 Nitrate response Mean NO 3 + NO 2 (mg/l) Calibration Period 1 Period 2 South Fork Fenton Clay BB Russell Lower Clay North BB South BB Treatment Headwaters Watershed Slope % Harvest % Distance to main stem (m) Distance to main stem gauge (m) Fenton ,200 Clay ,500 BB ,600 Russell ,800 North BB ,400

41 Magnitude of response relative to magnitude of disturbance Concentration vs. % clearcut Nitrate (mg/l) R² = % clearcut Watershed Slope % Harvest % Distance to main stem (m) Distance to main stem gauge (m) Fenton ,200 Clay ,500 BB ,600 Russell ,800 North BB ,400

42 Magnitude of response relative to magnitude of disturbance Concentration vs. % slope Nitrate (mg/l) R² = % slope Watershed Slope % Harvest % Distance to main stem (m) Distance to main stem gauge (m) Fenton ,200 Clay ,500 BB ,600 Russell ,800 North BB ,400

43 Magnitude of response relative to magnitude of disturbance Concentration vs. % clearcut % slope Nitrate (mg/l) R² = % clearcut % slope Watershed Slope % Harvest % Distance to main stem (m) Distance to main stem gauge (m) Fenton ,200 Clay ,500 BB ,600 Russell ,800 North BB ,400

44 Nitrate response Mean NO 3 + NO 2 (mg/l) Calibration Period 1 Period 2 South Fork Fenton Clay BB Russell Lower Clay North BB South BB Treatment Headwaters A single clearcut located 3,400 meters away on a steep slope produced a greater signal in the South Fork than five clearcuts combined

45 Discharge vs. concentration (L/s/ha) Fall storm samples Samples

46 Discharge vs. concentration (L/s/ha) South Fork storm Nov. 6, 2009 Nitrate (mg/l) (L/s/ha) North Fork storm Nov. 22, 2009 Nitrate (mg/l) Clay storm Nov. 27, Nitrate (mg/l) Fenton storm Nov. 12, Nitrate (mg/l) (L/s/ha) (L/s/ha)

47 Discharge vs. concentration

48 Discharge vs. concentration Jan. 19, 2005 Nitrate (mg/l) Oct. 27, 2009 Nitrate (mg/l) (L/s/ha) (L/s/ha)

49 South Fork discharge: 2005 & 2010 South Fork discharge Water Year (L/s/ha) South Fork discharge Water Year (L/s/ha)

50 Discharge vs. concentration

51 Nitrate response Mean NO 3 + NO 2 (mg/l) Calibration Period 1 Period 2 North Fork South Fork Treatment headwaters

52 Longitudinal attenuation & post harvest recovery In stream uptake of stream water nutrients (attenuation) was strong in the headwater streams Lower Clay clearcut provided information about attenuation in streams without riparian zones The removal of the canopy appears to increase in stream uptake North BB clearcut returned to [assumed] pre harvest concentrations after six years

53 Annual stream export Calibration Fertilization Treatment North Fork 50.5 (0.06) (0.96) (0.15) South Fork (37% clearcut) (0.68) (0.95) (0.96) Myers 5.2 (0.06) (2.18) 17.7 (0.21) Fenton (75% clearcut) 1.4 (0.06) 4.0 (0.18) 56.3 (2.49) Clay (36% clearcut) 11.5 (0.18) (1.67) 96.9 (1.49) DeMersseman 11.8 (0.08) (4.44) 30.7 (0.20) BB (32% clearcut) (3.38) (4.42) (2.74) Russell (15% clearcut) 11.8 (0.12) 97.6 (1.01) 62.4 (0.65) Values in kg/yr and kg/ha/yr Probably a 16 fold increase in annual stream export A portion of this increase is due to fertilizer Average input of nitrate from precipitation is approximately 0.7 kg/ha/yr Input was roughly equal to output

54 Calibration period

55 Calibration period

56 Calibration period

57 Calibration period

58 Calibration period

59 Calibration period

60 Calibration period

61 Calibration period

62 Calibration period

63 Calibration period

64 Calibration period

65 Calibration period

66 Calibration period

67 Calibration period

68 Calibration period

69 Calibration period

70 Calibration period

71 Fertilization

72 Fertilization

73 Post treatment period 1

74 Post treatment period 1

75 Post treatment period 1

76 Post treatment period 1

77 Post treatment period 1

78 Post treatment period 1

79 Post treatment period 1

80 Post treatment period 1

81 Post treatment period 1

82 Post treatment period 1

83 Post treatment period 1

84 Post treatment period 2

85 Post treatment period 2

86 Post treatment period 2

87 Post treatment period 2

88 Post treatment period 2

89 Post treatment period 2

90 Post treatment period 2

91 Post treatment period 2

92 Post treatment period 2

93 Post treatment period 2

94 Conclusions Forest management resulted in an statistically significant increase in stream water concentrations of nitrate, but. These increases were not biologically significant Local impacts to fish bearing streams were approximately equal to the cumulative impacts from non fish bearing streams A clearcut located on a steep slope is capable of producing a downstream impact greater than several moderately sloped clearcuts Output from the system was roughly equivalent to the input

95 Conclusions Topography was a much stronger predictor of the magnitude of response than was the size of the clearcut Antecedent moisture conditions and discharge can have a profound influence on stream water concentration The other nutrients did not appear to respond to timber harvest, BUT The use of urea fertilizer may have caused an increase in in stream uptake of several nutrients

96

97