[MARMAM] new paper in Remote Sensing of the Environment

Simone Panigada simo.pani at inwind.it
Sat Jun 28 15:54:15 PDT 2008


Dear Marmam subscribers,

the following article has been pubished on Remote 
Sensing of the Environment, and it is now available online at:

http://dx.doi.org/10.1016/j.rse.2007.11.017

Please note access to the full text of this 
article will depend on your personal or institutional entitlements.

Best regards,

Simone Panigada


Modelling habitat preferences for fin whales and 
striped dolphins in the Pelagos
Sanctuary (Western Mediterranean Sea) with physiographic and remote
sensing variables

Simone Panigada, Margherita Zanardelli, Monique MacKenzie, Carl Donovan,
Frédéric Mélin, Philip S. Hammond

A B S T R A C T

One of the needs of the Pelagos Sanctuary for the 
Conservation of Mediterranean Marine Mammals is
information on critical habitats for cetaceans. 
This study modelled habitat use and preferences of fin whales
and striped dolphins (the two most abundant 
species in the area) with the aim of providing this information,
using sighting data collected between 1993 and 
1999. The study area was divided into a 2Œ latitude by 2Œ
longitude grid. The explanatory variables 
considered in the models were physiographic variables (mean, range
and standard deviation of depth and slope, and 
distance from the nearest coastline) and remotely-sensed data
(Sea Surface Temperature and Chlorophyll-a 
concentration). The former were calculated for each cell using GIS
tools, while the latter were obtained from AVHRR 
and SeaWiFS sensors. Generalized Additive Models (GAMs)
with multidimensional smoothers were used to 
model the distribution of fin whales and striped dolphins in
relation to these variables, and Classification 
And Regression Trees were used for habitat characterization and
predictive models. The GAMs were coupled with 
Generalized Estimating Equations (GEEs) to account for
temporal autocorrelation in the errors and to 
help ensure model selection was reliable; the QIC statistic was
used alongside GEE-based p-values. Bathymetric 
features were the most valuable predictors in the Pelagos
Sanctuary area for both species. Sea Surface 
Temperature values were indicators of striped dolphin and fin
whale presence, with both species showing a 
tendency to prefer colder waters (21–24 °C). Chl-a levels were
selected by the GAM models only for striped 
dolphins, and with large associated uncertainty; this may be
related to the relatively brief period examined 
(only 2 years) and/or to any functional relationship operating at a
different geographical or temporal scale. The 
boosted classification trees however indicated an importance of
Chl-a for both species. The techniques applied to 
this dataset proved to be valuable tools to describe habitat use
and preferences of cetaceans, and the use of the 
remotely-sensed data can substantially improve the
predictions. The results of this study will be 
used for assessing critical habitats within the Pelagos Sanctuary
and will provide information for conservation and management in the Sanctuary.

Keywords: Mediterranean Sea, 
Conservation/management, Critical habitat, 
Habitat modelling, MPA, Fin whale, Striped dolphin

___________________________
Simone Panigada, Ph.D.
Vice-President
panigada at inwind.it

Tethys Research Institute
Viale G.B. Gadio 2, 20121 Milano, Italy
tel. +39 0272001947 / 0272013943
fax +39 0286995011
tethys at tethys.org
<http://www.tethys.org/>  
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