Knowledge of the relationships between species and
environmental variables requires understanding... more Knowledge of the relationships between species and environmental variables requires understanding the factors influencing the distribution patterns of populations. The Southern Brazilian coast is an important reproductive and calving site for Southern right whale Eubalaena australis (Desmoulins, 1822) (Cetartiodactyla, Balaenidae), which currently shows population growth, and variability in the number of individuals migrating, annually, to this area. This study investigated the hypothesis that the environmental and oceanographic factors ENSO (El Niño Southern Oscillation), SST (Sea Surface Temperature), shelf slope and amount of bays, influence southern right whales concentrating in specific areas, as well as the interannual variability in the number of individuals. Right whales data consisted of number and localization of individuals, sighted through helicopter expeditions between 27.4° and 30.4°S. Firstly, the population spatial distribution was analyzed through density estimative maps. Relationships between interannual variability in the number of right whales and ENSO were tested using nonparametric methods. Generalized Additive Models (GAMs) were applied for testing nonlinear relationships between right whales and the covariates SST, shoreline embayment index, shelf slope and latitude. Spatial distribution analysis showed higher concentration of right whales between Imbituba and Santa Marta Cape, which is a region characterized by cooler waters, many bays and higher shelf slope. Among the correlations tested between ENSO and right whales, it was significant at 0.05 only for the Nino4 index, on the feeding season, within a six years lag. GAMs results showed higher number of right whales around 28.5°S, SST between 15 and 18°C, higher number of bays and higher shelf slope, highlighting the importance of these environmental factors for habitat selection in right whales on the Southern Brazilian coast.
Knowledge of the relationships between species and
environmental variables requires understanding... more Knowledge of the relationships between species and environmental variables requires understanding the factors influencing the distribution patterns of populations. The Southern Brazilian coast is an important reproductive and calving site for Southern right whale Eubalaena australis (Desmoulins, 1822) (Cetartiodactyla, Balaenidae), which currently shows population growth, and variability in the number of individuals migrating, annually, to this area. This study investigated the hypothesis that the environmental and oceanographic factors ENSO (El Niño Southern Oscillation), SST (Sea Surface Temperature), shelf slope and amount of bays, influence southern right whales concentrating in specific areas, as well as the interannual variability in the number of individuals. Right whales data consisted of number and localization of individuals, sighted through helicopter expeditions between 27.4° and 30.4°S. Firstly, the population spatial distribution was analyzed through density estimative maps. Relationships between interannual variability in the number of right whales and ENSO were tested using nonparametric methods. Generalized Additive Models (GAMs) were applied for testing nonlinear relationships between right whales and the covariates SST, shoreline embayment index, shelf slope and latitude. Spatial distribution analysis showed higher concentration of right whales between Imbituba and Santa Marta Cape, which is a region characterized by cooler waters, many bays and higher shelf slope. Among the correlations tested between ENSO and right whales, it was significant at 0.05 only for the Nino4 index, on the feeding season, within a six years lag. GAMs results showed higher number of right whales around 28.5°S, SST between 15 and 18°C, higher number of bays and higher shelf slope, highlighting the importance of these environmental factors for habitat selection in right whales on the Southern Brazilian coast.
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Papers by Sabrina Espírito Santo
environmental variables requires understanding the factors influencing
the distribution patterns of populations. The Southern Brazilian coast
is an important reproductive and calving site for Southern right whale
Eubalaena australis (Desmoulins, 1822) (Cetartiodactyla, Balaenidae),
which currently shows population growth, and variability in the
number of individuals migrating, annually, to this area. This study
investigated the hypothesis that the environmental and oceanographic
factors ENSO (El Niño Southern Oscillation), SST (Sea Surface
Temperature), shelf slope and amount of bays, influence southern right
whales concentrating in specific areas, as well as the interannual
variability in the number of individuals. Right whales data consisted of
number and localization of individuals, sighted through helicopter
expeditions between 27.4° and 30.4°S. Firstly, the population spatial
distribution was analyzed through density estimative maps.
Relationships between interannual variability in the number of right
whales and ENSO were tested using nonparametric methods.
Generalized Additive Models (GAMs) were applied for testing
nonlinear relationships between right whales and the covariates SST,
shoreline embayment index, shelf slope and latitude. Spatial
distribution analysis showed higher concentration of right whales
between Imbituba and Santa Marta Cape, which is a region
characterized by cooler waters, many bays and higher shelf slope.
Among the correlations tested between ENSO and right whales, it was
significant at 0.05 only for the Nino4 index, on the feeding season,
within a six years lag. GAMs results showed higher number of right
whales around 28.5°S, SST between 15 and 18°C, higher number of
bays and higher shelf slope, highlighting the importance of these
environmental factors for habitat selection in right whales on the
Southern Brazilian coast.
environmental variables requires understanding the factors influencing
the distribution patterns of populations. The Southern Brazilian coast
is an important reproductive and calving site for Southern right whale
Eubalaena australis (Desmoulins, 1822) (Cetartiodactyla, Balaenidae),
which currently shows population growth, and variability in the
number of individuals migrating, annually, to this area. This study
investigated the hypothesis that the environmental and oceanographic
factors ENSO (El Niño Southern Oscillation), SST (Sea Surface
Temperature), shelf slope and amount of bays, influence southern right
whales concentrating in specific areas, as well as the interannual
variability in the number of individuals. Right whales data consisted of
number and localization of individuals, sighted through helicopter
expeditions between 27.4° and 30.4°S. Firstly, the population spatial
distribution was analyzed through density estimative maps.
Relationships between interannual variability in the number of right
whales and ENSO were tested using nonparametric methods.
Generalized Additive Models (GAMs) were applied for testing
nonlinear relationships between right whales and the covariates SST,
shoreline embayment index, shelf slope and latitude. Spatial
distribution analysis showed higher concentration of right whales
between Imbituba and Santa Marta Cape, which is a region
characterized by cooler waters, many bays and higher shelf slope.
Among the correlations tested between ENSO and right whales, it was
significant at 0.05 only for the Nino4 index, on the feeding season,
within a six years lag. GAMs results showed higher number of right
whales around 28.5°S, SST between 15 and 18°C, higher number of
bays and higher shelf slope, highlighting the importance of these
environmental factors for habitat selection in right whales on the
Southern Brazilian coast.