Extensive aquatic subsidies lead to territorial breakdown and high density of an apex predator

Energetic subsidies between terrestrial and aquatic ecosystems can strongly influence food webs and population dynamics. Our objective was to study how aquatic subsidies affected jaguar (Panthera onca) diet, sociality, and population density in a seasonally flooded protected area in the Brazilian Pantanal. The diet (n = 138 scats) was dominated by fish (46%) and aquatic reptiles (55%), representing the first jaguar population known to feed extensively on fish and to minimally consume mammals (11%). These aquatic subsidies supported the highest jaguar population density estimate to date (12.4 jaguars/100 km²) derived from camera traps (8,065 trap nights) and GPS collars (n = 13). Contrary to their mostly solitary behavior elsewhere, we documented social interactions previously unobserved between same-sex adults including cooperative fishing, co-traveling, and play. Our study demonstrates that aquatic subsidies, frequently described in omnivores, can also transform the ecology and behavior of obligate carnivores

Space use and movement of a Neotropical top predator: the endangered Jaguar

Não foi disponibilizado o número de páginas, pois não consta no arquivo.Accurately estimating home range and understanding movement behavior can provide important information on ecological processes. Advances in data collection and analysis have improved our ability to estimate home range and movement parameters, both of which have the potential to impact species conservation. Fitting continuous-time movement model to data and incorporating the autocorrelated kernel density estimator (AKDE), we investigated range residency of forty-four jaguars fit with GPS collars across five biomes in Brazil and Argentina. We assessed home range and movement parameters of range resident animals and compared AKDE estimates with kernel density estimates (KDE). We accounted for differential space use and movement among individuals, sex, region, and habitat quality. Thirty-three (80%) of collared jaguars were range resident. Home range estimates using AKDE were 1.02 to 4.80 times larger than KDE estimates that did not consider autocorrelation. Males exhibited larger home ranges, more directional movement paths, and a trend towards larger distances traveled per day. Jaguars with the largest home ranges occupied the Atlantic Forest, a biome with high levels of deforestation and high human population density. Our results fill a gap in the knowledge of the species’ ecology with an aim towards better conservation of this endangered/critically endangered carnivore—the top predator in the Neotropic

Boxplot and Posterior Density Estimates for male and female home range (log km²) [A and B], home range crossing time (log days) [C and D], velocity autocorrelation timescale (h) [E and F], and average distance traveled (Km/day) [G and H].

<p>Black line represents the difference between the posterior distribution of males and females, red represents the posterior distribution of females and blue represents the posterior distribution of males.</p

Space Use and Movement of a Neotropical Top Predator: The Endangered Jaguar - Fig 2

<p>(A) Variogram of a resident jaguar. Notice that the animal’s semi-variance reaches an asymptote within a few days, roughly representing the time to cross its home range. The red line represents the fitted model and the red shading represents the 95% CI. (B) A non-resident jaguar. Note the lack of a clear asymptote despite the fact that the animal was monitored for a long period (591 days). This lack of asymptote indicates that this animal is not range resident and thus a home range analysis for this individual is not appropriate. For both A and B, the fraction of the variogram displayed is 65% of the duration of each dataset.</p

Extent and conservation status of remaining habitat in Brazil’s major biomes and a portion of Atlantic Forest in Argentina.

<p>Jaguars are considered vulnerable in the Amazon and Pantanal, endangered in the Cerrado and critically endangered in the Atlantic Forest and Caatinga [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0168176#pone.0168176.ref014" target="_blank">14</a>,<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0168176#pone.0168176.ref015" target="_blank">15</a>].</p

Jaguars’ home range estimates in relation to human population size (square root transformed) across four study areas in Brazil and Argentina.

<p>Regression line is the species estimate from a linear regression model formulated in a Bayesian framework (Bayesian p-value = 0.495). Error lines are 95% CI.</p

Boxplot of home range (km²) for males and female jaguar by biome.

<p>Boxplot of home range (km²) for males and female jaguar by biome.</p

Movement parameters and home range sizes for GPS-collared jaguar across Brazil and Argentina biomes.

<p>Home ranges were estimated via 95% Kernel Density Estimates (KDE) and Autocorrelated Kernel Density Estimates (AKDE)<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0168176#t002fn001" target="_blank">¹</a>.</p

Map of study areas in Brazil and on the border of Brazil and Argentina.

<p>Source: mma.gov.br and wwf.org</p

Probability that the home range and movement parameter mean of male and female jaguars was different among locations (row vs column).

<p>Probability that the home range and movement parameter mean of male and female jaguars was different among locations (row vs column).</p