Acknowledgements UNM Hydrogeoecology Group NSF Grant DEB-9903973 Middle Rio Grande Conservancy...
1
Exotic LeafBiom ass LeafBiom ass (g/m 2 /yr) 0 20 40 60 80 Flood Nonflood 2000 Flood Nonflood 2001 Flood Nonflood 2002 Soil M oisture atN onflood Sites (2001) 2001 A pr M ay Jun Jul Aug S ep O ct N ov D ec Volum etric w atercontent(m L/g soil) 0.12 0.16 0.20 0.24 0.28 0.32 0.36 R io G rande Stage atBernardo (ft) 1 2 3 4 5 6 M onsoon rains Flood pulse Soil M oisture atFlood Sites (2001) 2001 Apr M ay Jun Jul Aug Sep O ct N ov D ec Volum etric w atercontent(m L/g soil) 0.12 0.16 0.20 0.24 0.28 0.32 0.36 R io G rande Stage atBernardo (ft) 1 2 3 4 5 6 25 cm below ground 40 cm below ground 55 cm below ground 70 cm below ground 85 cm below ground 100 cm below ground R io G rande stage atBernardo (ft) M onsoon rains Flood pulse ForestFloorLitterStorage 0 500 1000 1500 2000 2500 Ash-free D ry W eightofLitterStorage (g/m 2 ) Flood Nonflood 2002 Flood Nonflood 2003 N etN itrogen M ineralization N ov 01 M ar02 Jul 02 N ov 02 ug N O 3 - + N H 4 + /g soil 0 5 10 15 20 25 30 35 Flood Sites N onflood Sites D ate Soils C ollected Acknowledgements UNM Hydrogeoecology Group NSF Grant DEB-9903973 Middle Rio Grande Conservancy District Bosque del Apache National Wildlife Refuge City of Albuquerque Open Space Division New Mexico State Land Office Rio Grande Nature Center Belen Consolidated Schools Contacts Jennifer F. Schuetz 505- 277-5732 [email protected] du Manuel C. Molles, Jr. 505-277-3050 [email protected] Karyth L. Becenti 505- 277-5732 [email protected] http:// sevilleta.unm.edu/ ~cdahm/ Research/CRB/home/ index.html Flood versus nonflood riparian forests of the Middle Rio Grande, New Mexico: How do they differ? Jennifer F. Schuetz, Manuel C. Molles, Jr., and Karyth L. Becenti Department of Biology, University of New Mexico, Albuquerque, NM 87131 Abstract Over the past fifty years, volume and timing of the Rio Grande’s flow, including the annual flood pulse, have been altered due to damming and diversion of the river. As a result, the riparian forest, or bosque, is largely isolated from the river, and the native cottonwood forest is aging, not regenerating, and being invaded by exotics. Restoration of native bosque may require the use of managed floods; however, there is limited scientific data to assess this management activity. To provide information about ecological implications of overbank flooding, we are investigating how 4 flood and 4 nonflood sites within a 160 km stretch of the Middle Rio Grande differ ecologically. Significant differences between flood and nonflood sites were found for cottonwood leaf biomass, wood falling from the canopy, ground-dwelling arthropod abundance and community composition, soil moisture to a depth of 1 meter, and depth to groundwater. Differences suggested by means and standard errors were found for native, non-cottonwood leaf biomass, coarse woody debris, cottonwood leaf mass lost immediately following the May 2001 flood, net nitrogen mineralization, and forest floor litter storage. Final conclusions regarding variables that consistently distinguish flood from nonflood sites await complete analyses of datasets. Introduction • River restoration is an increasing priority worldwide. Much research has been conducted with the goal of restoring U.S. rivers such as the Kissimmee (Dahm et al. 1995), Colorado (Schmidt et al. 1998) and Rio Grande (Molles et al. 1998). In addition, restoration strategies for European rivers such as the Danube (Buijse et al. 2002; Tockner et al. 1998) and Rhine (Buijse et al. 2002) have been investigated. Even restoring streams in Nigeria has become important (Udoidiong 1999). • The Rio Grande’s riparian forest has not experienced a major flood since 1941 and 1942, and the river’s flow is about half of what it was 60 years ago (Crawford et. al. 1993). The riparian forest is mostly isolated from the river, exotics such as salt cedar and Russian Olive are invading the native cottonwood habitat, and the forest is getting older while very few young stands are being created. • Reinstating a spring flood in the Middle Rio Grande has been shown to promote nitrogen cycling and aid in transferring water and nutrients to riparian vegetation (Lieurance et al. 1994). • Another study in the Middle Rio Grande found less litterfall at a flood site, increased leaf decomposition during period of inundation, and no difference in standing stock of forest floor litter between flood and nonflood sites (Molles et al. 1998). • Ellis et al. (1999) observed that coarse woody debris and standing stock of forest floor litter were lower at a natural flood site compared to an experimental flood site and a nonflood site. Resulting leaf and wood decomposition rates increased with flooding. • Restoration of the native bosque along the hydrologically altered and highly controlled Rio Grande would require instituting managed late spring/early summer floods in years with good water availability. Literature Cited Buijse, A.D., H. Coops, M. Staras, L.H. Jans, G.J. Van Gees, R.E. Grifts, B.W. Ibelings, W. Oosterberg and F.C.J.M. Roozen. 2002. Restoration strategies for river floodplains along large lowland rivers in Europe. Freshwater Biology 47:889-907. Crawford, C.S., A.S. Culley, R. Leutheuser, M.S. Sifuentes, L.H. White, and J.P. Wilber. 1993. Middle Rio Grande Ecosystem: Bosque Biological Management Plan. U.S. Fish and Wildlife Service, District 2, Albuquerque, New Mexico, 291 pp. Dahm, C.N., K.W. Cummins, H.M. Valett, and R.L. Coleman. 1995. An ecosystem view of the restoration of the Kissimmee River. Restoration Ecology 3:225-238. Ellis, L. M., C. S. Crawford, and M. C. Molles, Jr. 1999. Influence of experimental flooding on litter dynamics in a Rio Grande riparian forest, New Mexico. Restoration Ecology 7(2):193-204 Lieurance, F. S., H. M. Valett, C. S. Crawford, and M. C. Molles, Jr. 1994. Experimental flooding of a riparian forest: restoration of ecosystem functioning. In: Proceedings of the Second International Conference on Ground Water Ecology, J. A. Stanford and H. M. Valett (eds.), pp. 365-374, American Water Resources Association, Herndon, Virginia. Molles, M. C., Jr., C. S. Crawford, L. M. Ellis, H. M. Valett, and C. N. Dahm. 1998. Managed flooding for riparian ecosystem restoration. BioScience 48:749-756. Schmidt, J.C., R.H. Webb, R.A. Valdez, G.R. Marzolf and L.E. Stevens. 1998. Science and values in river restoration in the Grand Canyon. Bioscience 48(9):735- 747 Tockner, K., F. Schiemer and J.V. Ward. 1998. Conservation by restoration: the management concept for a river-floodplain system on the Danube River in Austria. Aquatic Conservation: Marine and Freshwater Ecosystems 8:71-86. Udoidiong, O.M. 1999. Restoration of stream ecosystem integrity in Akwa Ibom State, Nigeria. Journal of Environmental Science 11(1):63-71. C ottonw ood LeafBiom ass C ollected as Litterfall *denotes significantdifference LeafBiom ass (g/m 2 /yr) 0 100 200 300 400 500 600 Flood Nonflood 2000 Flood Nonflood 2001* Flood Nonflood 2002 p=0.018 Total beetles: 88 29 Flood Sites April 2001 (pre-flood) 75 2 13 June 2001 (post-flood) 395 17 70 Total beetles: 482 63 June 2001 7 20 36 N onflood Sites April 2001 3 4 22 C arabids Tenebrionids Otherbeetles C oarse W oody D ebris (>2cm diameter) Average Biom ass ofC oarse W oody D ebris (M g/ha) 0 2 4 6 8 10 12 14 16 18 2002 2003 Flood Nonflood Flood Nonflood N ative LeafBiom ass Excluding C ottonw ood Leaves LeafBiom ass (g/m 2 /yr) 0 5 10 15 20 25 30 Flood Nonflood 2000 Flood Nonflood 2001 Flood Nonflood 2002 C ottonw ood LeafM ass Lost(2000-2001) bars representstandard errors D ate D ecom postion Bags C ollected 12/2000 2/2001 4/2001 6/2001 12/2001 Ash-free D ry-w eight(g) 2.0 2.5 3.0 3.5 4.0 4.5 Flood Sites N onflood Sites Flood D epth to W aterTable 2001 and 2002 red line denotes significantdifference (p<0.05) Jan 01 M ay 01 Sep 01 Jan 02 M ay 02 Sep 02 Jan 03 Depth to W aterTable (cm ) 20 40 60 80 100 120 140 160 180 N onflood Sites Flood Sites Beeping a well Average Annual W oody Biom ass C ollected as Litterfall *denotes significantdifference W oodyBiom ass(g/m 2 /yr) 0 200 400 600 800 1000 1200 1400 2000 2001* 2002 Flood Nonflood Flood Nonflood Flood Nonflood p=0.035 Litterfall tub Sampling for net nitrogen mineralization Sampling for coarse woody debris
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Transcript of Acknowledgements UNM Hydrogeoecology Group NSF Grant DEB-9903973 Middle Rio Grande Conservancy...
Exotic Leaf Biomass
Leaf
Bio
mas
s (g
/m2 /y
r)
0
20
40
60
80
Flood Nonflood
2000Flood Nonflood
2001Flood Nonflood
2002
Soil Moisture at Nonflood Sites (2001)
2001
Apr May Jun Jul Aug Sep Oct Nov Dec
Vo
lum
etric
wat
er c
ont
ent (
mL
/g s
oil)
0.12
0.16
0.20
0.24
0.28
0.32
0.36
Rio
Gra
nde
Sta
ge
at B
erna
rdo
(ft)
1
2
3
4
5
6
MonsoonrainsFlood pulse
Soil Moisture at Flood Sites (2001)
2001
Apr May Jun Jul Aug Sep Oct Nov Dec
Vo
lum
etric
wat
er c
ont
ent (
mL
/g s
oil)
0.12
0.16
0.20
0.24
0.28
0.32
0.36
Rio
Gra
nde
Sta
ge
at B
erna
rdo
(ft)
1
2
3
4
5
6
25 cm below ground40 cm below ground55 cm below ground70 cm below ground85 cm below ground100 cm below groundRio Grande stage at Bernardo (ft)
MonsoonrainsFlood pulse
Forest Floor Litter Storage
0
500
1000
1500
2000
2500
Ash
-fre
e D
ry W
eigh
t of L
itter
Sto
rage
(g/
m2 )
Flood Nonflood
2002
Flood Nonflood
2003
Net Nitrogen Mineralization
Nov 01 Mar 02 Jul 02 Nov 02
ug N
O3-
+ N
H4+
/g s
oil
0
5
10
15
20
25
30
35
Flood Sites Nonflood Sites
Date Soils Collected
AcknowledgementsUNM Hydrogeoecology Group
NSF Grant DEB-9903973
Middle Rio Grande Conservancy District
Bosque del Apache National Wildlife Refuge
City of Albuquerque Open Space Division
New Mexico State Land Office
Rio Grande Nature Center
Belen Consolidated Schools
ContactsJennifer F. Schuetz 505-277-5732 [email protected]
Manuel C. Molles, Jr. 505-277-3050 [email protected]
Karyth L. Becenti 505-277-5732 [email protected]
http://sevilleta.unm.edu/~cdahm/Research/CRB/home/index.html
Flood versus nonflood riparian forests of the Middle Rio Grande, New Mexico: How do they differ?
Jennifer F. Schuetz, Manuel C. Molles, Jr., and Karyth L. Becenti Department of Biology, University of New Mexico, Albuquerque, NM 87131
AbstractOver the past fifty years, volume and timing of the Rio Grande’s flow, including the annual flood pulse, have been altered due to damming and diversion of the river. As a result, the riparian forest, or bosque, is largely isolated from the river, and the native cottonwood forest is aging, not regenerating, and being invaded by exotics. Restoration of native bosque may require the use of managed floods; however, there is limited scientific data to assess this management activity. To provide information about ecological implications of overbank flooding, we are investigating how 4 flood and 4 nonflood sites within a 160 km stretch of the Middle Rio Grande differ ecologically. Significant differences between flood and nonflood sites were found for cottonwood leaf biomass, wood falling from the canopy, ground-dwelling arthropod abundance and community composition, soil moisture to a depth of 1 meter, and depth to groundwater. Differences suggested by means and standard errors were found for native, non-cottonwood leaf biomass, coarse woody debris, cottonwood leaf mass lost immediately following the May 2001 flood, net nitrogen mineralization, and forest floor litter storage. Final conclusions regarding variables that consistently distinguish flood from nonflood sites await complete analyses of datasets.
Introduction• River restoration is an increasing priority worldwide. Much research has been conducted with the goal of restoring U.S. rivers such as the Kissimmee (Dahm et al. 1995), Colorado (Schmidt et al. 1998) and Rio Grande (Molles et al. 1998). In addition, restoration strategies for European rivers such as the Danube (Buijse et al. 2002; Tockner et al. 1998) and Rhine (Buijse et al. 2002) have been investigated. Even restoring streams in Nigeria has become important (Udoidiong 1999).
• The Rio Grande’s riparian forest has not experienced a major flood since 1941 and 1942, and the river’s flow is about half of what it was 60 years ago (Crawford et. al. 1993). The riparian forest is mostly isolated from the river, exotics such as salt cedar and Russian Olive are invading the native cottonwood habitat, and the forest is getting older while very few young stands are being created.
• Reinstating a spring flood in the Middle Rio Grande has been shown to promote nitrogen cycling and aid in transferring water and nutrients to riparian vegetation (Lieurance et al. 1994).
• Another study in the Middle Rio Grande found less litterfall at a flood site, increased leaf decomposition during period of inundation, and no difference in standing stock of forest floor litter between flood and nonflood sites (Molles et al. 1998).
• Ellis et al. (1999) observed that coarse woody debris and standing stock of forest floor litter were lower at a natural flood site compared to an experimental flood site and a nonflood site. Resulting leaf and wood decomposition rates increased with flooding.
• Restoration of the native bosque along the hydrologically altered and highly controlled Rio Grande would require instituting managed late spring/early summer floods in years with good water availability.
Literature CitedBuijse, A.D., H. Coops, M. Staras, L.H. Jans, G.J. Van Gees, R.E. Grifts, B.W. Ibelings, W. Oosterberg and F.C.J.M. Roozen. 2002. Restoration strategies for river floodplains along large lowland rivers in Europe. Freshwater Biology 47:889-907.
Crawford, C.S., A.S. Culley, R. Leutheuser, M.S. Sifuentes, L.H. White, and J.P. Wilber. 1993. Middle Rio Grande Ecosystem: Bosque Biological Management Plan. U.S. Fish and Wildlife Service, District 2, Albuquerque, New Mexico, 291 pp.
Dahm, C.N., K.W. Cummins, H.M. Valett, and R.L. Coleman. 1995. An ecosystem view of the restoration of the Kissimmee River. Restoration Ecology 3:225-238.
Ellis, L. M., C. S. Crawford, and M. C. Molles, Jr. 1999. Influence of experimental flooding on litter dynamics in a Rio Grande riparian forest, New Mexico. Restoration Ecology 7(2):193-204
Lieurance, F. S., H. M. Valett, C. S. Crawford, and M. C. Molles, Jr. 1994. Experimental flooding of a riparian forest: restoration of ecosystem functioning. In: Proceedings of the Second International Conference on Ground Water Ecology, J. A. Stanford and H. M. Valett (eds.), pp. 365-374, American Water Resources Association, Herndon, Virginia.
Molles, M. C., Jr., C. S. Crawford, L. M. Ellis, H. M. Valett, and C. N. Dahm. 1998. Managed flooding for riparian ecosystem restoration. BioScience 48:749-756.
Schmidt, J.C., R.H. Webb, R.A. Valdez, G.R. Marzolf and L.E. Stevens. 1998. Science and values in river restoration in the Grand Canyon. Bioscience 48(9):735-747
Tockner, K., F. Schiemer and J.V. Ward. 1998. Conservation by restoration: the management concept for a river-floodplain system on the Danube River in Austria. Aquatic Conservation: Marine and Freshwater Ecosystems 8:71-86.
Udoidiong, O.M. 1999. Restoration of stream ecosystem integrity in Akwa Ibom State, Nigeria. Journal of Environmental Science 11(1):63-71.
*
Cottonwood Leaf Biomass Collected as Litterfall* denotes significant difference
Leaf
Bio
mas
s (g
/m2 /y
r)
0
100
200
300
400
500
600
Flood Nonflood
2000Flood Nonflood
2001*Flood Nonflood
2002p=0.018
Total beetles:88 29
Flood SitesApril 2001 (pre-flood)
75
2
13
June 2001 (post-flood)
395
17
70
Total beetles:482 63
June 2001
7
20
36
Nonflood Sites April 2001
3
4
22
Carabids
Tenebrionids
Other beetles
Coarse Woody Debris (>2cm diameter)
Ave
rage
Bio
mas
s of
Coa
rse
Woo
dy D
ebr
is (
Mg/
ha)
0
2
4
6
8
10
12
14
16
18
2002 2003Flood Nonflood Flood Nonflood
Native Leaf Biomass Excluding Cottonwood Leaves
Leaf
Bio
mas
s (g
/m2 /y
r)
0
5
10
15
20
25
30
Flood Nonflood
2000Flood Nonflood
2001Flood Nonflood
2002
Cottonwood Leaf Mass Lost (2000-2001)bars represent standard errors
Date Decompostion Bags Collected
12/2000 2/2001 4/2001 6/2001 12/2001
Ash
-fre
e D
ry-w
eigh
t (g)
2.0
2.5
3.0
3.5
4.0
4.5
Flood Sites Nonflood Sites
Flo
od
Depth to Water Table 2001 and 2002red line denotes significant difference (p<0.05)
Jan 01 May 01 Sep 01 Jan 02 May 02 Sep 02 Jan 03
Dep
th to
Wat
er T
able
(cm
)
20
40
60
80
100
120
140
160
180
Nonflood Sites
Flood Sites
Beeping a well
Average Annual Woody Biomass Collected as Litterfall* denotes significant difference
Woo
dy B
iom
ass
(g/m
2 /yr)
0
200
400
600
800
1000
1200
1400
2000 2001* 2002
Flood Nonflood Flood Nonflood Flood Nonflood
p=0.035
Litterfall tub
Sampling for net nitrogen mineralization
Sampling for coarse woody debris
