Post on 24-Jul-2020
Christopher J. Anderson and B. Graeme Lockaby
Auburn University, School of Forestry and Wildlife Sciences,
Auburn, AL 36849
Changes in forested wetland composition, structure, and processes along a tidal gradient on the
Apalachicola River, FL, USA
June 4, 2012
9th INTECOL International Wetland Conference, Orlando, FL
Introduction • Methods • Results/Discussion • Summary
Tidal freshwater forested wetlands Upriver extent of tidal influence
Most prominent on larger rivers with gradual relief
Normally freshwater but prone to periodic saltwater intrusion
Wetland forests across a tidal gradient on the Apalachicola River
Wetland forests across a tidal gradient on the Apalachicola River
Introduction • Methods • Results/Discussion • Summary
Introduction • Methods • Results/Discussion • Summary
Environmental services related to forested riparian wetlands along the river Carbon/nutrient cycling
Water quality
Wildlife habitat
Forest products
Wetland forests across a tidal gradient on the Apalachicola River
Project goal Using the Apalachicola River, evaluate how
forested wetland conditions and processes change across a tidal gradient
Objectives Examine how tidal hydrology influences:
Forest structure and composition
Physio-chemical conditions
Foliar nutrient cycling
Wetland forests across a tidal gradient on the Apalachicola River
Introduction • Methods • Results/Discussion • Summary
Lower
Apalachicola
River study
sites.
Wetland forests across a tidal gradient on the Apalachicola River
Study design
•17 transects
•37 forest plots (500 m2)
•10 water level recorders
Introduction • Methods • Results/Discussion • Summary
Wetland measures across a tidal gradient Species structure and composition (2007-10):
Measured forest tree (>2.5 cm dbh) density, basal area/growth, and size class
Determined species importance values and community composition
Forest soils and woody debris (2009-10)
Soil nutrient conditions (% C, N, S, exch. P)
Electrical conductivity
Coarse woody debris
Examined N and P leaf translocation and flux by tidal and non-tidal trees(2008)
Wetland forests across a tidal gradient on the Apalachicola River
Introduction • Methods • Results/Discussion • Summary
Wetland forests across a tidal gradient on the Apalachicola River
Cluster analysis dendrogram for lower Apalachicola River forested wetlands. Matrix color
coding based on species IV range between 0 (Min) and 64 (Max).
Swamp tupelo-
Bald cypress
Cabbage palm-
Sweet bay
Ogechee tupelo-
Overcup oak
Water oak- Carolina
ash
Anderson and Lockaby. 2011. Wetlands 31:895-906.
Introduction • Methods • Results/Discussion • Summary
Community composition
Wetland forests across a tidal gradient on the Apalachicola River
Hummock
Hollow
Introduction • Methods • Results/Discussion • Summary
Wetland forests across a tidal gradient on the Apalachicola River
Importance values for Nyssa biflora and Taxodium distichum related to plot elevation
coefficient of variation in tidal stands along the lower Apalachicola River.
y = -0.0002x3 + 0.0254x2 - 1.3004x + 22.192
R2 = 0.3297
0.0
0.1
0.2
0.3
0.4
0.5
0.6
50 55 60 65 70
Plot elevation CV
Taxo
diu
m d
isti
ch
um
IV
1.0
y = -0.0307x + 2.1483
R2 = 0.6218
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
50 55 60 65 70
Plot elevation CV
Nyssa b
iflo
ra IV
1.0
Micro-topography and species composition
Introduction • Methods • Results/Discussion • Summary
Wetland forests across a tidal gradient on the Apalachicola River
Mean (±SE) density and tree size classes for tidal (n=7) and non-tidal (n=8) forest stands
along the lower Apalachicola River.
0
100
200
300
400
500
600
700
800
900
2.5 - 5.0 cm 5.0 - 10.0 cm 10.0 - 15.0 cm 15.0 - 20.0 cm > 20.0 cm
Tree DBH class
No
. s
tem
s h
a-1
Non-tidal
Tidal
Mean forest tree density:
Tidal: 1446 ±159 stems ha-1
Non-tidal: 962 ±962 stems ha-1
Anderson, Lockaby, and Click. In revision.
Tree stem density and size class
Introduction • Methods • Results/Discussion • Summary
Wetland forests across a tidal gradient on the Apalachicola River
Mean (±SE) basal area and annual increment growth of tidal (n=7) and non-tidal (n=8) forest
stands
-0.4
-0.2
0
0.2
0.4
0.6
0.8
2007-08 2008-09 2009-10
BA
I (m
2 h
a-1
yr-1
)
Tidal
Non-tidal
Mean forest basal area*
Tidal: 35.6 ±3.3 m2 ha-1
Non-tidal: 64.4 ±2.8 m2 ha-1
Anderson, Lockaby, and Click. In revision.
Basal area and increment growth
Introduction • Methods • Results/Discussion • Summary
Wetland forests across a tidal gradient on the Apalachicola River
Mean (±SE) surface soil (0-15 cm) measures for tidal (n=20) and non-tidal (n=17) forest plots along
the lower Apalachicola River. Letters denote significant differences (p<0.05) per nested ANOVA.
Electrical
conductivity
(mmhos cm-1)
0.0
1.0
2.0
3.0
4.0
Non-
tidal
Tidal
Carbon (%)
0.0
5.0
10.0
15.0
Non-
tidal
Tidal
Nitrogen (%)
0.0
0.2
0.4
0.6
0.8
1.0
Non-
tidal
Tidal
Sulfur (%)
0.0
0.1
0.2
0.3
0.4
Non-
tidal
Tidal
Mean surface soil measures
Exch.
Phosphorus
(ppm)
0.0
1.0
2.0
3.0
4.0
5.0
Non-
tidal
Tidal
Introduction • Methods • Results/Discussion • Summary
a a a a a b b b b b
Wetland forests across a tidal gradient on the Apalachicola River
Mean (±SE) coarse woody debris (CWD) for tidal (n=3) and non-tidal (n=5) forest stands along the
lower Apalachicola River. * denotes significant difference detected at p<0.05 per ANOVA.
0
1
2
3
4
5
6
<7.62 cm >7.62 cm
CWD size class
Mg
ha
-1Non-tidal
Tidal*
Anderson, Lockaby, and Click. In revision.
Coarse woody debris
Introduction • Methods • Results/Discussion • Summary
Wetland forests across a tidal gradient on the Apalachicola River
Percent tidal (n=19) and non-tidal (n=9) trees sampled with complete, intermediate, or
incomplete resorption proficiency of a) nitrogen and b) phosphorus (per Killingbeck 1996).
0
20
40
60
80
100
Complete Intermediate Incomplete
Pe
rce
nt
Non-tidal
Tidal
0
20
40
60
80
100
Complete Intermediate Incomplete
Pe
rce
nt
Non-tidal
Tidal
(<3 μg P
cm-2)
(3-8 μg P
cm-2)
(>8 μg P
cm-2)
(<50 μg N
cm-2)
(50-75 μg N
cm-2)
(>75 μg N
cm-2)
a) b)
Nutrient resorption proficiency
Anderson and Lockaby. 2011. Aquatic Botany 95:153-160.
Introduction • Methods • Results/Discussion • Summary
Wetland forests across a tidal gradient on the Apalachicola River
Estimated litterfall and nutrient flux for tidal (n=5) and non-tidal (n=3) forest stands along the
lower Apalachicola River.
1 4399 35.8 1.4
2 3997 31.9 1.4
15 3672 31.2 1.2
7pt 4513 36.8 1.4
WS2 2472 21.0 1.0
Avg. 3811 31.3 1.3
3 8107 100.4 5.3
5 5661 71.6 3.9
7 6180 77.5 4.0
Avg. 6649 83.2 4.4
N (kg ha-1
) P (kg ha-1
)
Litterfall
(kg ha-1
)Plot
Introduction • Methods • Results/Discussion • Summary
Tidal
Non-tidal
Anderson and Lockaby. 2011. Aquatic Botany 95:153-160.
Litterfall and nutrient flux
Summary of findings: Forest tree species and community composition
provided clear indications of tidal influence
Microtopography within tidal sites appears to be important for community composition
Tidal hydrology and periodic saltwater intrusion resulted in consistent differences in soil C, N, S, exch. P, electrical conductivity, and other soil measures
Tidal wetlands appeared to be P-limited based on nutrient resorption efficiencies and N:P and C:P ratios
Wetland forests across a tidal gradient on the Apalachicola River
Introduction • Methods • Results/Discussion • Summary
Summary of findings (continued): Tidal wetlands appeared to be P-limited based
on leaf nutrient resorption measures and foliage/litterfall N:P and C:P ratios.
The nutrient pool associated with tidal forests is significantly lower than non-tidal forests.
Wetland forests across a tidal gradient on the Apalachicola River
Introduction • Methods • Results/Discussion • Summary
Acknowledgements AU Center for Forest Sustainability, McIntire-Stennis Grant
Program
Apalachicola National Estuarine Reserve, Florida Wildlife Research Institute, Florida Fish and Wildlife Conservation Commission
A. Cerro, F. Barksdale, J. Clewley, N. Click, J. Dow, R. Governo, R. Jolly, T. Kesler, L.Levi, H. Light, J. Mitchell, J. Morse, W. Morse, J. Timpone, J. Trusty, J. Wanat
Wetland forests across a tidal gradient on the Apalachicola River
Introduction • Methods • Results/Discussion • Summary
Introduction • Methods • Results/Discussion
Environmental services related to forested riparian wetlands Carbon cycling
Wildlife habitat
Water quality
Wetland forests across a tidal gradient on the Apalachicola River