Eric A. GrahamUCLA Department of Ecology and Evolutionary Biology

Ecological Applications of CENS Technologies at the James Reserve

Summer interns:

•Caitlin Hamilton•Geoff Robertson•Marina Sharifi

Ecological Projects

• Development of multi-scale methods for ecological research• Micrometeorological variation• Sap flow• Phenology• New and expanded projects

Micrometeorological Variation – Temperature

Date (month)

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Ave

rage a

ir t

em

pera

ture

(°C

)

0

5

10

15

20

25TrailfinderMosscamKeenwild

Time (hour of day)0 3 6 9 12 15 18 21 0In

stan

taneou

s air t

em

pera

ture

(°C

)

-5

0

5

10

15

20

25

30SummerWinter

* * *

* P < 0.05

• Multiple networked micrometeorological stations at the James Reserve allow for short and long-range comparisons of ecologically important variables.

• Temperature• Relative Humidity• Light• Soil moisture

Micrometeorological Variation – Light

• Biological responses to some stochastic meteorological variables can be readily modeled

• Photosynthetic light response curve.

Photosynthetic photon flux (µmol photons m-2 s-1)

0 500 1000 1500 2000

Net

pho

tosy

nthe

sis

(µm

ol C

O2

m-2

s-1

)

0

5

10

15

20

Micrometeorological Variation – Soil Moisture

Soil water content (v/v)

0.00 0.02 0.04 0.06 0.08 0.10

Wat

er

pote

ntia

l (M

Pa)

-25

-20

-15

-10

-5

0

water potential at which certain plants will experience drought

• Biological responses to some non-predictable meteorological variables can be readily modeled.

• Soil water availability

Time (day)

Feb Mar Apr May Jun Jul Aug Sep

Soi

l wat

er c

onte

nt (

v/v)

0.00

0.02

0.04

0.06

0.08

0.10

Rainfall eventAug 14, 2004

Sap flow in Manzanita and Pine

Time of day (h)0 6 12 18 0

Sap

flo

w v

eloc

ity(m

m s

-1)

0.0

0.5

1.0

1.5V

apor

Pre

ssur

e D

iffer

ence

(g H

2O m

-3 a

ir)

0

10

20

30

40

dew point = 9.1 °Cdew point = 15.3 °C

• Small-scale meteorological measurements can be used to explain sap flow data.

• Sap flow is driven by differences in water vapor concentration and is thus affected by leaf temperatures and relative humidity and requires local micrometeorological measurements.

Sap flow in Manzanita and Pine

Time of day (h)0 6 12 18 0

Sap

flow

vel

ocity

(mm

s-1

)

0.0

0.5

1.0

1.5P

PF

at l

eaf s

urfa

ce(

mol

pho

tons

m-2

s-1

)

0

100

200

300

400

500

600

East branchWest branch

Sap flow in Manzanita and Pine

Time (days)23 24 25 26 27 28 29 30

Sap

flow

(m3 m

-2 s

-1)

0

5

10

15

20

25

• Water moving from the soil through plants into the atmosphere (sap flow) can indicate water use strategies and water sources.

Inexpensive sap flow probes can be used for continuous long-term monitoring of water movement and signs of stress.

Bark beetle damage to the xylem system of pines can be monitored

Phenology

June 4 – 4.2 cm2 June 21 – 20.5 cm2

June 30 – 21.1 cm2 July 21 – 21.5 cm2

• Timing of leaf flushes and leaf longevity can be used to determine how species may be responding to disturbance and to climate change.

• Leaf flushes influence herbivore abundance and distribution and have long-range impacts on food webs.

Phenology

0

20

40

60

80

Ave

rag

e le

af

len

gth

(m

m)

0

20

40

60

80

Average leaf number

8 6 4 2 1 3 5 7 90

20

40

60

80

May 4

May 11

Jun 210

20

40

60

80 May 18

n = 30 buds

n = 38 buds

n = 42 buds

n = 42 buds

centerleaf

of bud• Leaves expanded quickly in Rhododendron in the spring of 2004. Leaf flush began later for individuals closer to the stream and continued longer into the summer.

• Additionally, final leaf size was greater in individuals near the stream.

• Microclimate affects could be responsible for such variation even over such a short distance (10 meters).

Phenology

Time (date)

4/20 4/27 5/03 5/10 5/17 5/24 6/01 6/07 6/14

Tra

nse

ct

po

sitio

n (

m)

0

5

10

15

20

shaded

exposed

54

30

42

55

2718 4

12

0

20

40

60

Surface (below leaf litter)20 cm below surface

Time (day)

2 3 4 5 6

So

il te

mpe

ratu

re (

°C)

0

20

40

60

near stream in shade

in clearing exposed

• Bracken fern fronds emerged at different dates along an exposure gradient.

New and Expanded Projects

• Microdendrometers will be used to measure changes in tree girth.• sensors based on strain

gauges are available with signal outputs within the range of CMS inputs.

• Transpiration estimation by “Energy Balance” methods• remote measurements of

radiation, temperature and wind speed can be used to calculate latent heat loss.

New and Expanded Projects

• Sharp transitions from primary forest to open areas provide a means of understanding the ecological effects of forest fragmentation

La Selva Biological station, Costa RicaMicroclimate Dynamics Across Forest Edges

New and Expanded Projects

Mobility in a high resolution camera will allow remote measurements of plant distribution and growth

dynamics

Temporally and spatially dense measurements of understory light environments can help understand complex forest patterns of biodiversity