INVESTIGADORES
TRAVAINI Alejandro
artículos
Título:
Where do Swainson`s hawks winter? Satellite images used to identify potential habitat
Autor/es:
JOSÉ HERNÁN SARASOLA; JAVIER BUSTAMANTE; JUAN JOSÉ NEGRO; ALEJANDRO TRAVAINI
Revista:
Diversity and Distributions
Editorial:
Blackwell Publishing
Referencias:
Lugar: Oxford; Año: 2008 vol. 14 p. 742 - 753
ISSN:
1366-9516
Resumen:
ABSTRACT
During recent years, predictive modelling techniques have been increasingly used to
identify regional patterns of species spatial occurrence, to explore specieshabitat
relationships and to aid in biodiversity conservation. In the case of birds, predictive
modelling has been mainly applied to the study of species with little variable inter-annual
patterns of spatial occurrence (e.g. year-round resident species or migratory
species in their breeding grounds showing territorial behaviour). We used predictive
models to analyse the factors that determine broad-scale patterns of occurrence and
abundance of wintering Swainsons hawks (Buteo swainsoni). This species has been
the focus of field monitoring in its wintering ground in Argentina due to massive
pesticide poisoning of thousands of individuals during the 1990s, but its unpredictable
pattern of spatial distribution and the uncertainty about the current wintering area
occupied by hawks led to discontinuing such field monitoring. Data on the presence
and abundance of hawks were recorded in 30 × 30 km squares (n = 115) surveyed
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
the focus of field monitoring in its wintering ground in Argentina due to massive
pesticide poisoning of thousands of individuals during the 1990s, but its unpredictable
pattern of spatial distribution and the uncertainty about the current wintering area
occupied by hawks led to discontinuing such field monitoring. Data on the presence
and abundance of hawks were recorded in 30 × 30 km squares (n = 115) surveyed
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
the focus of field monitoring in its wintering ground in Argentina due to massive
pesticide poisoning of thousands of individuals during the 1990s, but its unpredictable
pattern of spatial distribution and the uncertainty about the current wintering area
occupied by hawks led to discontinuing such field monitoring. Data on the presence
and abundance of hawks were recorded in 30 × 30 km squares (n = 115) surveyed
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
the focus of field monitoring in its wintering ground in Argentina due to massive
pesticide poisoning of thousands of individuals during the 1990s, but its unpredictable
pattern of spatial distribution and the uncertainty about the current wintering area
occupied by hawks led to discontinuing such field monitoring. Data on the presence
and abundance of hawks were recorded in 30 × 30 km squares (n = 115) surveyed
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
the focus of field monitoring in its wintering ground in Argentina due to massive
pesticide poisoning of thousands of individuals during the 1990s, but its unpredictable
pattern of spatial distribution and the uncertainty about the current wintering area
occupied by hawks led to discontinuing such field monitoring. Data on the presence
and abundance of hawks were recorded in 30 × 30 km squares (n = 115) surveyed
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
the focus of field monitoring in its wintering ground in Argentina due to massive
pesticide poisoning of thousands of individuals during the 1990s, but its unpredictable
pattern of spatial distribution and the uncertainty about the current wintering area
occupied by hawks led to discontinuing such field monitoring. Data on the presence
and abundance of hawks were recorded in 30 × 30 km squares (n = 115) surveyed
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
(Buteo swainsoni). This species has been
the focus of field monitoring in its wintering ground in Argentina due to massive
pesticide poisoning of thousands of individuals during the 1990s, but its unpredictable
pattern of spatial distribution and the uncertainty about the current wintering area
occupied by hawks led to discontinuing such field monitoring. Data on the presence
and abundance of hawks were recorded in 30 × 30 km squares (n = 115) surveyed
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.
× 30 km squares (n = 115) surveyed
during three austral summers (200103). Sixteen land-use/land-cover, topography,
and Normalized Difference Vegetation Index (NDVI) variables were used as predictors to
build generalized additive models (GAMs). Both occurrence and abundance models
showed a good predictive ability. Land use, altitude, and NDVI during spring previous to
the arrival of hawks to wintering areas were good predictors of the distribution of
Swainsons hawks in the Argentine pampas, but only land use and NDVI entered
the model of abundance of the species in the region. The predictive cartography
developed from the models allowed us to identify the current wintering area of
Swainsons hawks in the Argentine pampas. The highest occurrence probability and
relative abundances for the species were predicted for a broad area of south-eastern
pampas that has been overlooked so far and where neither field research nor conser-vation
efforts aiming to prevent massive mortalities has been established.