Laura Marisa Bellis

Planning conservation for multiple species while accounting for habitat availability and connectivity under uncertain land-use changes presents a major challenge. This study proposes a protocol to identify strategic conservation areas by assessing the functional connectivity of key bird species under future land-use scenarios in the Chaco Serrano of Córdoba, Argentina. We modeled three land-use scenarios for 2050: business as usual, sustainability, and intensification. Using the Equivalent Connected Area index, we evaluated functional connectivity for Chlorostilbon lucidus, Polioptila dumicola, Dryocopus schulzii, Milvago chimango, and Saltator aurantiirostris for 1989, 2019, and 2050, incorporating information about habitat specialization and dispersal capacity to reflect differences in ecological responses. All species showed declining connectivity from 1989 to 2019, with further losses expected under future scenarios. Connectivity declines varied by species and were not always proportional to habitat loss, highlighting the complex relationship between land-use change and functional connectivity. Surprisingly, the sustainability scenario led to the greatest losses in connectivity, emphasizing that habitat preservation alone does not ensure connectivity. Using the Integral Connectivity Index, we identified habitat patches critical for maintaining connectivity, particularly those vulnerable under the business as usual scenario. With a spatial prioritization analysis we identified priority conservation areas to support future landscape connectivity. These findings underscore the importance of multispecies, connectivity-based planning and offer a transferable framework applicable to other regions.

(1) Background: Changes in the spatial, temporal, and magnitude-related patterns of fires caused by humans are expected to exacerbate with climate change, significantly impacting ecosystems and societies worldwide. However, our understanding of fire regimes in many regions remains limited, largely due to the inherent complexity of fire as an ecological process. Pyrogeography, combined with unsupervised learning methods and the availability of long-term satellite data, offers a robust framework for approaching this problem. The purpose of the study is to identify the pyroregions of the Argentine Gran Chaco, the world’s largest continuous tropical dry forest region. (2) Methods: Using globally available fire occurrence datasets, we computed five fire metrics, related to the extent, frequency, intensity, size, and seasonality of fires at three spatial scales (5, 10, and 25 km). In addition, we tested two widely used cluster algorithms, the K-means algorithm and the Gaussian Mixture Model (GMM). (3) Results and Discussion: The identification of pyroregions was dependent on the clustering algorithm and scale of analysis. The GMM algorithm at a 25 km scale ultimately demonstrated more coherent ecological and spatial distributions. GMM identified six pyroregions, which were labeled based on three metrics in the following order: annual burned area (categorized in low, regular or high), interannual variability of fire (rare, occasional, frequent), and fire intensity (low, moderate, intense). The values were as follows: LRM (22% of study area), ROI (19%), ROM (14%), LOM (10%), ROL (9%), and HFL (4%). (4) Conclusions: Our study provides the most comprehensive delineation of the Argentine Gran Chaco’s Dry Forest pyroregions to date, and highlights both the importance of determining the optimal scale of analysis and the critical role of clustering algorithms in efforts to accurately characterize the diverse attributes of fire regimes. Furthermore, it emphasizes the importance of integrating fire ecology principles and fire management perspectives into pyrogeographic studies to ensure a more comprehensive and meaningful characterization of fire regimes.

(1) Background: Land-use change threatens biodiversity globally, making it essential to anticipate future impacts. (2) Methods: We assess future land-use change scenarios as a tool for analyzing the taxonomic and functional richness of birds in the Serrano forest. We developed two change scenarios: The “Business as usual” scenario assumes that the trend of land-use change observed between 2004 and 2019 will continue without modifications by 2035 and 2050. The “Sustainable” scenario seeks to achieve a sustainable relationship between anthropogenic land-use activities and ecosystem conservation. We created distribution models and derived the potential distribution of the taxonomic and functional richness of forest and understory specialist birds in the change scenarios. (3) Results: The taxonomic and functional richness of both bird groups was strongly affected in the “Business as usual” change scenario, which presented extreme deforestation events, while the “Sustainable” change scenario tended to maintain bird richness over time. We detected areas with a reduction in richness greater than 20% and areas where richness increased due to being distant from urbanization and exotic forests.

The South American Gran Chaco is among the most threatened ecoregions worldwide. Although land use change in the plains of this region has been widely studied, less is known about the southern mountainous areas. Our main goal was to analyze the land cover change dynamics in the Chaco Serrano between 1989 and 2019. We developed 3 land cover maps for the Sierras Chicas of central Argentina (1989, 2004 and 2019) and performed a land cover change analysis. Serrano forests lost 67,055 ± 8127 ha, and the annual rate of deforestation increased from −0.58 (1989–2004) to −1.87 (2004–2019). Between 1989 and 2019, grasslands exhibited the second‐highest negative annual rate of change (−0.59). In 2019, shrublands became the dominant cover, increasing their size by 30% compared to 1989. Urban areas had the highest positive annual rate of change (5.60) and increased their extension from 1% of the total study area in 1989 to 5% in 2019. Invasive alien species expanded rapidly but only in specific areas. Our main findings show that land cover change processes in the Chaco Serrano mountains have differed from those observed in the plain areas of the Chaco and were consistent with those observed in other mountainous regions of the world. The current scenario for the Serrano forest is critical, and if conservation strategies are not applied in the near future, it could be expected that most of the Serrano forest, a unique ecosystem within the Chaco, would eventually disappear.

The accurate detection and characterization of vegetation covers are essential to support monitoring and prevention actions in different fields of application, ranging from agricultural management to environmental conservation. Polarimetric decompositions over L-band SAR data (SAOCOM) were evaluated here to enable it. Cameron [1], Van zyl [2], Generalyzed Freeman Durden [2], Cloud-Pottier [3], Yamaguchi [4], GRVI [5] and Cloude [2] decompositions were explored in two contrasting seasons (winter and summer, dry and rainy seasons in the study area, respectively) to differentiate vegetation cover types in Chaco serrano (Córdoba, Argentina). Differences between vegetation covers were found, particularly between grasslands, shrublands and forests. Specifically, the volume components, which exhibited significant differences between seasons for all vegetation covers, would be suitable for studying vegetation phenology from time series data.

Land‐use change is one of the main threats to biodiversity at the global level, and subtropical dry forests are not exempt from such a threat. Recent studies suggest that species can become extinct with a considerable time lag, even if no further habitat loss occurs. Hence, there may be an extinction debt, which poses a great challenge to conservation. Here, we analyzed the response of taxonomic and functional richness of forest and understory specialist birds to 30 years (data from 1989, 2004 and 2019) of land‐cover and land‐use changes in the Chaco Serrano forest of central Argentina. Our results showed the occurrence of extinction debt in both forest and understory specialist birds, with such debt being greater in forest specialist birds. Results for species trait debt were inconclusive. We also found evidence that birds are not equally sensitive to land‐use change, indicating a species‐specific response. We conclude that the current presence of some large native forest patches and an intermediate degree of isolation in the region might be prolonging the persistence of some bird species and traits. Moreover, ecological legacies can strongly affect the current species distribution pattern and the permanence of functional traits in fragmented landscapes. These findings should be considered in conservation planning.