Kelp gulls attack Southern right whales: a conservation concern?

Kelp gulls (Larus dominicanus) feed on pieces of skin and blubber they rip from Southern right whales’ (Eubalaena australis) backs in their breeding areas at Península Valdés, Argentina, producing injuries. This behavior has increased since the first record in 1972, and some authors have suggested that constant gull harassment could have a negative effect on right whale population. The main goal of this study is to assess the variables that most affect the gull attacks. We analyzed 5359 whale-watching sightings made during trips from Puerto Pirámides (42º34′S, 64º16′W) along the whale breeding seasons (June–December) 2005 to 2007. The most important factors affecting the attacks include the presence of a mother–calf pair, the time within the season, the distance to the coast and the wind velocity. There is also concern of possible transmission of infectious diseases in the attacks since increasing number of whales with different patterns of skin lesions have been observed.Fil: Fazio, Ana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Bertellotti, Néstor Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina. Wild Earth Foundation; ArgentinaFil: Villanueva, María Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentin

Integrative assessment of immunity, health-state, growth and survival of Magellanic penguin chicks in a colony exposed to ecotourism

Accumulating reports of negative impacts of tourist activities on wildlife emphasize the importance of closely monitoring focal populations. Although some effects are readily noticed, more subtle ones such as changes in physiological functions of individuals might go overlooked. Based on evidence of altered physiology associated with ecotourism on Magellanic penguins Spheniscus magellanicus, here we performed an integrated assessment using a diverse physiological toolkit together with more traditional fitness-related measures to better understand mechanisms and potential consequences. Chicks exposed to tourism showed altered immune condition and elevated flea prevalence, reinforcing previous findings. Tourism-exposed female, but not male, chicks also showed reduced hematocrit and plasma protein levels, providing evidence of sex-specific susceptibility. Physiological alterations detected in tourism-exposed young (week 1-2) chicks were maintained and the effect on flea infestation increased during the study period (week 4-5 of post-hatch). Despite the effects on physiology, these did not seem to translate into immediate fitness costs. No detectable effects of tourism were found on brood sex ratios, chick growth and body condition, and survival until week 5-6 post-hatch. No effects were detected on reproductive output and only a marginal effect on nest survival despite previous reports of tourism-associated alterations in stress indices of adults. This disconnection could result if the physiological changes are not strong enough to impact the measured fitness-related traits and/or only show impacts later in the brooding cycle or even after chick emancipation from their parents. In this respect, a potential link between our results and the previously documented female-biased juvenile mortality in this colony deserves consideration. Integrative assessments of anthropogenic impacts on wildlife should include understanding of physiological mechanisms and individual-level responses to enable the development or tailoring of management measures for effective conservation of exposed populations.This is a manuscript of an article published as Cumplido, M., V. D'Amico, M. Bertellotti, M. Atencio, S. J. Dinsmore, and M. G. Palacios. "Integrative assessment of immunity, health-state, growth and survival of Magellanic penguin chicks in a colony exposed to ecotourism." Science of The Total Environment 870 (2023): 161915. doi:10.1016/j.scitotenv.2023.161915. Posted with permission.This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License

The interplay among grazing history, plant-plant spatial interactions and species traits affects vegetation recovery processes in Patagonian steppe

Since the early 20 century Patagonian arid steppes have been subjected to overgrazing that led to the degradation of plant communities. We hypothesized that the interplay among grazing history, plant-plant spatial interactions and species traits affects recovery and assemblage of shrub community after short-term abandonment in north-eastern Patagonian arid steppe (Peninsula Valdés, Argentina). We compared six sites (two in grazed pastures, and four in short-term ungrazed pastures, two of which intensively grazed, while the other two low intensity grazed in the past) with regard to: shrub cover percentage (10 m × 10 m plots); shrub patch dimension, species richness, and spatial interactions among shrub species depending on patch dimension (patches sampled along transects); species richness and composition, vertical relations among species, and traits related to avoidance strategies and disturbance (1 m × 1 m plots sampled along transects). Our results indicated that recovery processes in abandoned pastures act through the increase in shrub patch size, formation of new patches, change in patch composition and richness, and in within-patch relations among shrub species. No significant differences were found between sites subjected to different past grazing intensities. The increase in shrub cover was due to a significant expansion of the dominant shrub Chuquiraga avellanedae. The mechanism of new patch formation and spread was mainly based on facilitative processes acting between the dwarf shrubs, poorly palatable and disliked by wild herbivores, and young individuals of the dominant species emerging from their canopy. As patch size increased, dwarf shrubs were covered by taller ones or grew at the edge of the patch, indicating a phase of competitive exclusion. Plant-plant spatial interactions involved changes in the composition of plant traits linked to avoidance strategies, which were indicators of grazed conditions and of plots with shrub cover lower than 50%, while less need for defence against animal browsing was highlighted in ungrazed pastures and shrub-dominated plots. As the density of herbivores is recognized as the key factor in biodiversity conservation and ecosystem recovery, management plans devoted to conservation of biodiversity and forage resources should work to recreate grazing conditions close to the wild ones or to impose a short-term period of ecosystem rest that allows the plant community to recover

Oxidative status and stress during highly energetic life-history stages of Chinstrap Penguins: breeding versus molting

Life-history stages such as reproduction and molt are energetically costly. Reproductive costs include those associated not only with offspring production, but also protecting and provisioning young. Costs typically associated with molting include decreased thermoregulatory and locomotive performance, and increased metabolic and nutritional costs. Energetic demands may disrupt homeostasis, particularly in terms of its maintenance (e.g., oxidative stress and immunity). Few investigators have explored the relationship between effort (increased metabolic rate) and oxidative status and stress by comparing life-history stages with different energetic demands. However, comparative studies are crucial for understanding the processes of energy allocation and their consequences for different physiological functions. Our objective was to determine how two highly demanding life-history stages, breeding and molting, affected oxidative balance in Chinstrap Penguins (Pygoscelis antarcticus), a species where these two activities do not overlap. We found that the heterophil/lymphocyte (H/L) ratio was significantly higher during breeding than molting; oxidative damage was also higher during breeding. In contrast, we found no significant differences between these stages in total antioxidant capacity. We also found sex differences, with males having greater oxidative damage than females. Our results suggest that breeding is more stressful and more demanding for Chinstrap Penguins than molting, and provide further support for the relationship between effort, in terms of increased metabolic rate, and oxidative balance.his study was funded by the Spanish Ministry of Economy and Competitiveness (CTM2011‐24427 and CTM2015‐64720). RCC held a Spanish Ministry of Economy and Competitiveness FPI grant (BES2012‐059299)

The interplay among grazing history, plant-plant spatial interactions and species traits affects vegetation recovery processes in Patagonian steppe

Since the early 20th century Patagonian arid steppes have been subjected to overgrazing that led to the degradation of plant communities. We hypothesized that the interplay among grazing history, plant-plant spatial interactions and species traits affects recovery and assemblage of shrub community after short-term abandonment in north-eastern Patagonian arid steppe (Peninsula Valdés, Argentina). We compared six sites (two in grazed pastures, and four in short-term ungrazed pastures, two of which intensively grazed, while the other two low intensity grazed in the past) with regard to: shrub cover percentage (10 × 10 m plots); shrub patch dimension, species richness, and spatial interactions among shrub species depending on patch dimension (patches sampled along transects); species richness and composition, vertical relations among species, and traits related to avoidance strategies and disturbance (1 × 1 m plots sampled along transects). Our results indicated that recovery processes in abandoned pastures act through the increase in shrub patch size, formation of new patches, change in patch composition and richness, and in within-patch relations among shrub species. No significant differences were found between sites subjected to different past grazing intensities. The increase in shrub cover was due to a significant expansion of the dominant shrub Chuquiraga avellanedae. The mechanism of new patch formation and spread was mainly based on facilitative processes acting between the dwarf shrubs, poorly palatable and disliked by wild herbivores, and young individuals of the dominant species emerging from their canopy. As patch size increased, dwarf shrubs were covered by taller ones or grew at the edge of the patch, indicating a phase of competitive exclusion. Plant-plant spatial interactions involved changes in the composition of plant traits linked to avoidance strategies, which were indicators of grazed conditions and of plots with shrub cover lower than 50%, while less need for defence against animal browsing was highlighted in ungrazed pastures and shrub-dominated plots. As the density of herbivores is recognized as the key factor in biodiversity conservation and ecosystem recovery, management plans devoted to conservation of biodiversity and forage resources should work to recreate grazing conditions close to the wild ones or to impose a short-term period of ecosystem rest that allows the plant community to recover