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Ruddy-headed goose Chloephaga rubidiceps has a migratory population that overwinters mainly in the Pampas region, Argentina, and breeds in Southern Patagonia. This population has decreased considerably, with less than 800 individuals remaining to date. We conducted the first assessment on the influence of environmental and anthropogenic-impact (wind farms and high-voltage networks) variables on ruddy-headed goose migration pathways across the Patagonian coast by applying kernel density analyses and statistical procedures. We used satellite tracking data obtained from six ruddy-headed geese during their migration pathways between 2015 and 2018. Five core distribution areas were identified during migration. During autumn migration, core areas were associated with high primary productivity and low elevation areas, while during spring migration they were located in the proximity of watercourses and waterbodies. We found that more than 30% of the grid cells included in the influence area of high-voltage networks overlapped with high-density areas for ruddy-headed geese during both migrations. Around 30% of the grid cells included in the influence zone of wind farms overlapped with high-density areas for ruddy-headed goose during autumn migration; while this applied to only 13% during spring migration. We highlight areas of high-risk along the distributional range of the species where large-scale patterns of collision mortality are likely to occur and mitigation measures should be prioritized. We suggest proactive measures that could mitigate future collisions with energy infrastructure because, given their threatened status, a few deaths may have a large effect on the small remnant population. [ABSTRACT FROM AUTHOR]

In this paper, transformations of internal links within the indigenous political field are explored, focusing on the last decades of the frontier. This period, in which the state progresses towards its political unification and institutional consolidation, state policies regarding Indian people show a more unified profile and aim to create the conditions necessary for the frontiers advance. The peace treaties policy, extended to almost the whole indigenous map, will be one of the devices through the state will attempt to canalize and to order its relations with different chiefs and groups. Our interest attempts to identify the probable conditionings and influences of this policy on the indigenous population at the conformation, strengthening and weakening of their political alliances. We intend specifically to reconstruct-within this context-the process of the Calfucurá's leadership, to identify the impact of state interventions over the extent of his political summoning capacity during this period. [ABSTRACT FROM AUTHOR]

The objective of this work is to evaluate temporal variation of dento‐alveolar lesions in hunter‐gatherer groups who inhabited the middle course of the Negro River during the late Holocene (ca. 3000‐750 years BP) in order to discuss cultural practices and changes in the paleodiet. Caries, dental calculus, periodontal disease, periapical lesions, antemortem tooth loss, tooth wear, dislocation, and osteoarthrosic lesions in the temporomandibular joint were analysed. The sample is represented by 567 teeth and 547 alveoli, corresponding to 32 adult and subadult individuals, who were divided into two periods for comparative purposes: pre‐1000 and post‐1000 BP. The results indicate a low prevalence of oral lesions without differences between sex and age. In the pre‐1000 BP period, there is a larger frequency of antemortem tooth loss, parafunctional wear of the anterior teeth, dental dislocations, and osteoarthrosis in the mandibular condyles compared with the post‐1000 period. This tendency indicates that the individuals would have been exposed to greater stress in chewing. However, the variations were not significant, so there is no clear evidence of changes in the diet and particularly in carbohydrate and plant intake through the late Holocene. Severe tooth wear is the main factor that caused some pathologies (e.g., antemortem tooth loss), and limited the development of others (e.g., caries). The results obtained here agree with other microregions from northeastern Patagonia and differ from Humid Pampas, eastern Pampa‐Patagonian transition, and lower course of the Negro River due to differences in carbohydrate consumption in the last ca. 1000 years BP. [ABSTRACT FROM AUTHOR]

Diversity often increases ecosystem functioning and enhances stability, but this relationship has been evaluated at the community scale and considering, for the most part, only species richness. Here, we explored the relationship between landscape diversity and either the coefficient of variation or the interannual standard deviation of greenness in Pampean grasslands and Patagonian meadows, and tried to elucidate the mechanisms responsible for the resulting patterns. The coefficient of variation decreased with increasing landscape richness in Pampas but remained constant in Patagonia, while the interannual standard deviation of greenness decreased in both regions. The diversity-variability relationship in Pampean grasslands was largely accounted for by the mechanism of statistical averaging, while in Patagonian meadows, it was accounted for by a combination of statistical averaging, mean-variance rescaling and positive covariation of landscape units. There were no cases of negative covariance among landscape units. This is the first demonstration that landscape diversity increases stability of ecosystem functioning. [ABSTRACT FROM AUTHOR]