urban-to-rural gradients
DESCRIPTION
Urban-to-rural gradients. More abundant in quiet sites. R 2 = 0.4 p = 0.0002. White-breasted Nuthatch. Red-bellied Woodpecker. % change from noisy to quiet sites. More abundant in noisy sites. % song overlap with traffic noise. Effects on bird composition. - PowerPoint PPT PresentationTRANSCRIPT
Urban-to-rural gradientsUrban-to-rural gradients
100 80 60 40 20 0
overlap.traffic3500
-100
-50
0
50
100
150pe
rcen
t.di
ff%
cha
nge
from
noi
sy t
o qu
iet
site
s
% song overlap with traffic noise
R2 = 0.4p = 0.0002
More abundantin quiet sites
More abundant in noisy sites
White-breasted Nuthatch
Red-bellied Woodpecker
Effects on bird composition
Fragmentation in the Fragmentation in the “Triangle”“Triangle”
38% population 38% population growth:1990-2000growth:1990-2000
About 20.5% of About 20.5% of forest cover lostforest cover lost
Triangle Research Triangle Research Initiative: Initiative: economics, forest economics, forest ecology, bird ecology, bird behavior…behavior…
Land-use change until Land-use change until 19201920
Mostly Mostly hardwood foresthardwood forest
Much of Much of landscape landscape clearedcleared Not too wet or Not too wet or
too drytoo dry Not too hillyNot too hilly
Farm abandonment and Farm abandonment and successionsuccession
Many farms Many farms abandonedabandoned ““Worst of the best”Worst of the best” Now dominated by Now dominated by
pinespines Pinus taedaPinus taeda Pinus echinataPinus echinata
Hardwood forests Hardwood forests changingchanging More red mapleMore red maple Less oakLess oak
Fragmentation in Fragmentation in “Triangle”-“Triangle”-
central questionscentral questions What is the effect of forest What is the effect of forest
fragmentation on NC Piedmont forests?fragmentation on NC Piedmont forests? Where is deforestation occurring?Where is deforestation occurring? How do edges affect abiotic and biotic How do edges affect abiotic and biotic
processes in forests?processes in forests? Do patterns of fragmentation affect patterns Do patterns of fragmentation affect patterns
of forest dynamics at a large scale?of forest dynamics at a large scale?
What are the effects of What are the effects of edges?edges?
Change in abiotic conditionsChange in abiotic conditions For plants, big things are light, For plants, big things are light,
temperaturetemperature Change in biotic conditionsChange in biotic conditions
Increased flux of exotic speciesIncreased flux of exotic species
Experimental design-Experimental design-forest dynamicsforest dynamics
66 edges selected66 edges selected 30m transect30m transect All trees greater than All trees greater than
breast height sampled breast height sampled within 5mwithin 5m
All stems sampled All stems sampled within 1mwithin 1m
Tree cores taken from Tree cores taken from trees > 10cm DBHtrees > 10cm DBH
Forest
Non-Forest
Light sensor
Schematic of edge transects.
Temp. sensor and moisture sensor
Experimental design-Experimental design-microclimatemicroclimate
8 intensive 8 intensive transectstransects 50% south-facing50% south-facing 50% deciduous50% deciduous
2 light sensors at 2 light sensors at 0m and 30m0m and 30m
3 temp/humidity 3 temp/humidity sensors are 0m,5m, sensors are 0m,5m, and 30mand 30m
Forest
Non-Forest
Light sensor
Schematic of edge transects.
Temp. sensor and moisture sensor
What’s the climate like What’s the climate like near edges?near edges?
Sensor data Sensor data recorded every 10 recorded every 10 minutesminutes
Aggregated to daily Aggregated to daily PPFD, max. and PPFD, max. and min. temp., and RHmin. temp., and RH
3-factor crossed 3-factor crossed ANOVA design: ANOVA design: south, deciduous, south, deciduous, monthmonth
More light…More light…
Canopy closure is less Canopy closure is less near edgenear edge
Light is more: Light is more: +3.9molPPFD/day+3.9molPPFD/day
The magnitude of the The magnitude of the effect varies monthly:effect varies monthly: Jan.: +6.0 mol PPFD/dayJan.: +6.0 mol PPFD/day Aug.: +3.5 mol PPFD/dayAug.: +3.5 mol PPFD/day
Seasonality varies with Seasonality varies with aspectaspect0
2040
6080
100
Perce
nt ca
nopy
clos
ure
0 0-5 5-10 10-15 15-20 20-25 25-30
Distance from edge (m)
Higher maximum Higher maximum temperatures…temperatures…
South-facing edges, max. temp. South-facing edges, max. temp. +3.0+3.0°C°C
North-facing edges, max. temp. North-facing edges, max. temp. +0.2°C+0.2°C
Magnitude of edge effect on max. Magnitude of edge effect on max. temp. does not vary by monthtemp. does not vary by month
No effect on minimum temperatureNo effect on minimum temperature
Greater swings in RHGreater swings in RH
Similar RH at night near edgesSimilar RH at night near edges Much lower RH during the Much lower RH during the
afternoonafternoon Complicated three-way interaction: Complicated three-way interaction:
Month, South, EdgeMonth, South, Edge Low RLow R22
Do trees grow faster?Do trees grow faster?
Over 1200 cores Over 1200 cores collectedcollected
Average 5-year Average 5-year growth rate growth rate calculatedcalculated
Log(Growth) = Log(Growth) = f(dist. to edge, f(dist. to edge, species, soil species, soil nutrients, soil nutrients, soil moisture proxies, moisture proxies, competition) competition)
Some do…Some do…
DBH in cm
ave
rag
e g
row
th r
ate
in m
m
0 10 20 30 40 50
05
10
15
0-5mgreater than 5m
Pinus taeda
DBH in cm
ave
rag
e g
row
th r
ate
in m
m
0 10 20 30 40 50
05
10
15
0-5mgreater than 5m
Liriodendron tulipifera
Some don’tSome don’t
No growth response from red maple and No growth response from red maple and sweet gumsweet gum
Environmental variables measured explain Environmental variables measured explain about 65% of plot-level variance, and are about 65% of plot-level variance, and are more important than edge effectsmore important than edge effects
Soil variables are very important, Soil variables are very important, especially Percent Base Saturationespecially Percent Base Saturation
Greater TCI means a greater growth ratesGreater TCI means a greater growth rates Only significant interaction term: for Only significant interaction term: for P. P.
taeda taeda there is a greater increase in growth there is a greater increase in growth rates on dry edges than on wet edgesrates on dry edges than on wet edges
But lot’s of exoticsBut lot’s of exotics
Increased Tree-of-Increased Tree-of-Heaven, Princess Heaven, Princess Tree…Tree…
Also increased oak Also increased oak abundanceabundance
Reduced Reduced abundance of red abundance of red maplemaple