Transcript Species Traits Analysis_Debinski Kerr Larivee_Oct_2015x

Species Traits as Filters of
Climate-Induced Range Expansion
DIANE DEBINSKI JEREMY KERR AND MAXIM LARRIVÉE
IOWA STATE UNIVERSITY, UNIVERSITY OF OTTAWA,
INSECTARIUM DE MONTRÉAL
INTRODUCTION
• As climate warms, species are
expected to move poleward or
up in elevation to track the
environmental conditions to
which they are most adapted
(Parmesan et al. 1999; Chen,
Hill et al. 2011)
• However, this movement and
the subsequent colonization of
new habitat may be affected by
species-specific habitat affinities
and life history traits that
facilitate or impede range
expansion
Warming over time
0°C
Diagram courtesy of Jay Fitzsimmons
map from vidiani.com
INTRODUCTION
• Even if the “thermal envelope” is ideal, the
vegetation conditions or other
environmental parameters may not be
conducive
http://www.greenpeace.org/canada/en/campaigns/forests/boreal
• Similarly, traits such as wingspan or
voltinism may act as a filter in defining
which species can successfully colonize
new regions
• Build on use of trait analysis:
• Ockinger et al. (2010) Eco. Letters
Debinski et al. (2013) Ecology
INTRODUCTION (CONT.)
• Using massive, long-term butterfly
datasets, we asked:
1. How do abundance patterns
change over time from early vs.
recent time?
• 2. How do butterfly traits affect the
changes in abundance?
Red to Blue = Increasing to
decreasing butterfly species
richness in the past century
Red to Blue =
High to low
butterfly species
richness
• 1901-1970
• 1985-2010
HYPOTHESES
Species with larger wingspans and more generations per
year would respond more quickly to climate change and
thus show positive trends in abundance.
Generalist species would show increasing trends, whereas
specialists would be more likely to show decreasing trends.
BUTTERFLY METHODS: BUTTERFLY DATA
 Compared species abundance patterns from historical time
periods (1901-1970) and recent time periods (1985-2010).
 Restricted analysis to ~100 species that were well sampled
(i.e., they had abundances of 50 or more during each time
period)
BUTTERFLY METHODS: TRAITS
 Wingspan
 Preferred habitat - open (e.g., grassland), closed (e.g., forest) or
edge (e.g., riparian edge).
 Moisture - wet habitat, dry habitat or both.
 Voltinism - 1-3 generations per year.
Sources: Scott, Opler, BAMONA, Iftner, Acorn, Layberry, xerces.org., natureserve.org
BUTTERFLY
METHODS
Grid cells at a 400 km
resolution
(equal area projection)
BUTTERFLY METHODS: STANDARDIZING ABUNDANCE
A standardized abundance was calculated for each species by
subtracting the mean count over all species and locations within
each time frame.
For each species at each location standardized abundance at
time t1 was subtracted from the standardized abundance at time t2
to calculate a standardized difference in abundance.
We then used a linear model to model standardized difference in
abundance:
std_diff ~ y + wingspan + habitat_type + moisture + voltinism +
wingspan * y + habitat_type * y + moisture * y + voltinism * y
Where y= latitude
RESULTS: TRAITS AND ABUNDANCE CHANGES
Table 2: Coefficients from the full model with all main effects for difference in standardized
abundance. All factors were significant.
Model
wingspan
1.47
Moisture: dry
•
(base=
wet)
-51.66
moisture: both
(base=wet)
38.15
Voltinism2
(base=1)
73.58
Voltinism3
(base=1)
131.58
Note: interaction with latitude was
also significant for all factors
HABITAT GENERALISTS
http://butterfliesofamerica.com/phyciodes_pulchella_camillus_live1.htm
P I E R I S R A P A E , P H Y C I O D E S P U C H E L L A ,
Z E L I C A O N , A N D C U P I D O A M Y N T U L A .
P A P I L I O
http://www.butterfliesandmoths.org/species/Cupido-amyntula
3 GENERATIONS PER YEAR
http://www.learnaboutbutterflies.com/North%20America%20-%20Vanessa%20virginiensis.htm
http://commons.wikimedia.org/wiki/File:Pieris_rapae_total_Richard_Bartz.jpg
http://commons.wikimedia.org/wiki/File:Vanessa_cardui_3_Luc_Viatour.jpg
• Pieris rapae, Vanessa cardui, and Vanessa virginiensis.
R E S U L T S : PROPORTIONAL CHANGE IN ABUNDANCE
between 1901-1970(t1) and 1985-2010 (t2) for species with 1 (left), 2 (middle), or 3 (right) generations per year.
• 1 Generation
• 2 Generations
• 3 Generations
SUMMARY: ABUNDANCE PATTERNS
Species with the following traits showed increases in relative
abundance over time:
o Larger wingspans
o More generalized habitat requirements
o Higher growth rates (voltinism)
No significant differences relative to habitat affinities
SYNTHESIS
• Our results support the hypothesis that traits are indeed acting
as an important filter differentiating which species will respond
most quickly to climate change.
ACKNOWLEDGEMENTS
 University of Ottawa, Distinguished Visiting Researcher Program
 Iowa State University, Faculty Professional Development Assignment
 E-butterfly: www.e-butterfly.ca
 Statistical consulting: Lendie Follett, ISU