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The major histocompatibility complex (MHC) is a genetic region in jawed vertebrates that contains key genes involved in the immune response. Associations between the MHC and avian malaria infections in wild birds have been observed and mainly explored in the Northern Hemisphere, while a general lack of information remains in the Southern Hemisphere. Here, we investigated the associations between the MHC genes and infections with Plasmodium and Haemoproteus blood parasites along a latitudinal gradient in South America. We sampled 93 rufous-collared sparrows (Zonotrichia capensis) individuals from four countries, Colombia, Ecuador, Peru, and Chile, and estimated MHC-I and MHC-II allele diversity. We detected between 1-4 (MHC-I) and 1-6 (MHC-II) amino acidic alleles per individual, with signs of positive selection. We obtained generalized additive mixed models to explore the associations between MHC-I and MHC-II diversity and latitude. We also explored the relationship between infection status and latitude/biome. We found a non-linear association between the MHC-II amino acidic allele diversity and latitude. Individuals from north Chile presented a lower MHC genetic diversity than those from other locations. We also found an association between deserts and xeric shrublands and a lower prevalence of Haemoproteus parasites. Our results support a lower MHC genetic in arid or semi-arid habitats in the region with the lower prevalence of Haemoproteus parasites.

UNESCO's MAB Programme promotes a people-centered conservation strategy to strengthen the sustainability of social and ecological systems. However, there exist knowledge gaps regarding its implementation in specific contexts. For this study, a mixed-methods sequential exploratory design was employed. In the first phase, an initial content analysis of the management program of the El Cielo Biosphere Reserve (CBR) and the functions of the statutory framework of UNESCO's MAB program was conducted. This analysis, which was human-driven but facilitated by artificial intelligence tools, underwent rigorous triangulation and expert validation to strengthen the reliability and robustness of the findings. Subsequently, the Management Effectiveness Tracking Tool (METT3) was issued to researchers, community members, civil servants, and former civil servants related to the management of the CBR. The 2024 results (n = 15) were contrasted with those obtained in 2017 (n = 15) using a quantitative approach consisting of descriptive, non-parametric, and Bayesian statistical techniques. We identified some problems in the implementation of the MAB-UNESCO Programme in the CBR, mainly due to the outdated management program and lack of effective governance, as well as the lack of understanding of the implications of being a MAB-UNESCO biosphere reserve. A numerical trend of deterioration in the effectiveness of the CBR's management was detected, with overall ratings of 44.78% and 29.62% in 2017 and 2024, respectively. This was associated with a lack of regulation, weak coordination among key actors, and a progressive reduction in funding. The findings of this study are useful to guide the transition of the CBR towards a conservation model that responds to current problems and contributes to the advancement of knowledge on the implementation of the MAB Programme in specific contexts. [ABSTRACT FROM AUTHOR]

For migratory birds, events happening during any period of their annual cycle can have strong carry-over effects on the subsequent periods. The strength of carry-over effects between non-breeding and breeding grounds can be shaped by the degree of migratory connectivity: whether or not individuals that breed together also migrate and/or spend the non-breeding season together. We assessed the annual cycle of the White-crested Elaenia (Elaenia albiceps chilensis), the longest-distance migrant flycatcher within South America, which breeds in Patagonia and spends the non-breeding season as far north as Amazonia. Using light-level geolocators, we tracked the annual movements of elaenias breeding on southern Patagonia and compared it with movements of elaenias breeding in northern Patagonia (1,365 km north) using Movebank Repository data. We found that elaenias breeding in southern Patagonia successively used two separate non-breeding regions while in their Brazilian non-breeding grounds, as already found for elaenias breeding in the northern Patagonia site. Elaenias breeding in both northern and southern Patagonia also showed high spread in their non-breeding grounds, high non-breeding overlap among individuals from both breeding sites, and similar migration phenology, all of which suggests weak migratory connectivity for this species. Elucidating the annual cycle of this species, with particular emphasis on females and juveniles, still requires further research across a wide expanse of South America. This information will be critical to understanding and possibly predicting this species' response to climate change and rapid land-use changes. [ABSTRACT FROM AUTHOR]

We present a reliable and robust open dynamic chamber for measuring greenhouse gas exchange in peatlands with minimal disturbance of the ground. This chamber, called the "skirt chamber", is based on a transparent plastic film placed above an open frame made of sparse interwoven wires and expanded around the base of the chamber below a steel chain that ensures contact to the ground, avoiding damage, trenching, and cutting vegetation. Gas exchange is determined using a portable gas analyzer from a mass balance in which the imperfect sealing of the chamber to the ground is quantified through the injection of a methane pulse. The method was tested on a pristine peatland dominated by Sphagnum magellanicum located on Navarino Island in the subantarctic Magellanic ecoregion in Chile. Our results indicate that the skirt chamber allowed the determination of methane fluxes and ecosystem respiration in about 20 min, with a limit of detection of 0.185 mg CH 4 m -2 h -1 and 173 mg CO 2 m -2 h -1 , respectively. We conclude that the skirt chamber is a minimally intrusive, fast, portable, and inexpensive method that allows the quantification of greenhouse gas emissions with high spatial resolution in remote locations and without delay. [ABSTRACT FROM AUTHOR]

The Magellanic sub‐Antarctic Forest is home to the world's southernmost avian community and is the only Southern Hemisphere analogue to Northern Hemisphere temperate forests at this latitude. This region is considered among the few remaining pristine areas of the world, and shifts in environmental conditions are predominantly driven by climate variability. Thus, understanding climate‐driven demographic processes is critical for addressing conservation issues in this system under future climate change scenarios. Here, we describe annual survival patterns and their association with climate variables using a 20‐year mark–recapture data set of five forest bird species in the Cape Horn Biosphere Reserve. We develop a multispecies hierarchical survival model to jointly explore age‐dependent survival probabilities at the community and species levels in a group of five forest passerines. At the community level, we assess the association of migratory behavior and body size with survival, and at the species level, we investigate the influence of local and regional climatic variables on temporal variations of survival. We found a positive effect of precipitation and a negative effect of El Niño Southern Oscillation on juvenile survival in the white‐crested Elaenia and a consistent but uncertain negative effect of temperature on survival in juveniles and 80% of adults. We found only a weak association of climate variables with survival across species in the community and no temporal trends in survival for any of the species in either age class, highlighting apparent stability in these high austral latitude forests. Finally, our findings provide an important resource of survival probabilities, a necessary input for assessing potential impacts of global climate change in this unique region of the world. [ABSTRACT FROM AUTHOR]

Illustrates the reciprocal relationships between the sciences and environmental ethics by examining the Darwinian theory of evolution and discussing its implications for ecologists and ethicists. (CCM)