Spatial Models of Abundance and Habitat Preferences of Commerson’s and Peale’s Dolphin in Southern Patagonian Waters

Funding: This research was possible with the support of the Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). Funding for travel to and accommodation for NAD in Aberdeen, Scotland was provided by CONICET and Cetacean Society International. The work of NAD was part of a postdoctoral fellowship funded by CONICET. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

Guanaco Sighting

Data sets corresponding to "Spatial abundance models and seasonal distribution for guanaco (Lama guanicoe) in central Tierra del Fuego, Argentina" publication

Kelp geese (Chloephaga hybrida) and Flightless steamer ducks (Tachyeres pteneres) in the Beagle Channel: the importance of islands in providing safe nesting habitat

We describe nest-site characteristics and studied breeding habitat use of Kelp geese (Chloephaga hybrida) and Flightless Steamer ducks (Tachyeres pteneres) along 137km of coastline on the northern shore of the Beagle Channel, Argentina, and 87 km of island coastline. Also, we examined the importance of vegetation cover, predation and tourism on the distribution of nests among islands. We found all nests only on islands and islets. Nesting sites for both species were strongly associated with higher proportions of high vegetation cover (shrubs), and for Kelp geese they were also associated to the absence of terrestrial predators. Tourist presence on islands was not associated to the presence of nest for neither species. The northern coasts of the Beagle Channel and the islands and islets along the channel have similar habitat types. However, the islands and islets are relatively inaccessible to mammalian terrestrial predators compared to the coast of the channel were terrestrial predators are frequently recorded. Therefore, islands and islets seem to provide a relatively safe nesting habitat for Kelp geese and Flightless Steamer ducks by offering refuge mainly from ground predators. Additionally, habitat changes caused by increased human disturbance along the northern shore of the Beagle Channel may also explain the presence of nests only on islands and islets, though further studies are needed to assess these effects. This study provides new information on the breeding habitat and nesting sites of Flightless Steamer ducks and Kelp geese in the Beagle Channel, which in the future may contribute to the identification of priority breeding sites, and habitats and habitat features to protect. Also, it highlights the importance of islands and islets of the Beagle Channel as a safe breeding refuge for these two ground nesting seabirds.Fil: Liljesthrom, Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Schiavini, Adrian Carlos Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Saenz Samaniego, Ricardo Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Fasola, Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Raya Rey, Andrea Nélida. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentin

Spatially explicit model and uncertainty map of Peale’s dolphin.

<p>Density surface model of average abundance of Peale’s dolphin in the study area analyzed (a); averages were taken over the time periods where surveys were conducted, predicting using the appropriate dynamic variances for that time period. The map of per cell coefficient of variation (CV) for the fitted model shows the largest uncertainty in the southeast portion of the study area (b); uncertainty was combined over multiple time periods by noting that the variance of a sum is the sum of the covariances. Cell area is 100km².</p

Relationships between the geographic position and the linear predictor in the model for Commerson’s dolphin.

<p>The number in brackets in “s” gives the effective degrees of freedom (a measure of flexibility) of each term. The contours (and colours) are the effect of the spatial smooth on abundance on the scale of the link function.</p

Relationships between the smooth terms and the linear predictor in the model for Peale’s dolphin.

<p>From left to right: (a) geographic position (easting, northing), (b) depth, and (c) sea surface temperature (SST). Dashed lines represent 95% confidence intervals. The number in brackets in each “s” gives the effective degrees of freedom (a measure of flexibility) of each term. The contours (and colours) are the effect of the spatial smooth on abundance on the scale of the link function.</p

Autocorrelation of deviance residuals between segments (lags) for the fitted density surface model of Peale’s dolphin.

<p>The dashed line represents the 95% confidence interval.</p

Tracks of the different scientific cruises surveys during austral summer and fall months.

<p>Each single line of each cruise represents one day of survey effort. Black polygon indicates the region of study analyzed. White polygon indicates the primary range of distribution of Commerson’s dolphin in the southwest South Atlantic Ocean. Red polygon indicates the primary range of distribution of Peale’s dolphin in the southwest South Atlantic Ocean.</p

Autocorrelation of deviance residuals between segments (lags) for the fitted density surface model of Commerson’s dolphin.

<p>The dashed line represents the 95% confidence interval.</p