Ciencias de la Tierra y Medioambientales
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A melting-pot for Pterodroma petrels on Rapa Nui: ecological divergence and reproductive isolation in a contact zone
(FRONTIERS MEDIA SA, 2023/07/27) Plaza Paula, Cristofari Robin, Gouin Nicolas, Soto-Gamboa Mauricio, Luna-Jorquera Guillermo
Speciation is thought to depend on general ecological segregation rather than on strict allopatry in species with planetary-scale foraging ranges, such as Pterodroma petrels. Separation in both breeding islands and foraging grounds are generally considered to be the conditions for prezygotic isolation. However, it is unclear how both can be maintained in a context of ongoing distributional range shifts due to global change, with range contractions and expansions caused by changing land use in breeding territories and oceanographic conditions impacting productivity areas. In this context, we expect that wherever the fragile balance of allopatric segregation breaks down, gene flow may be re-established across the borders of what is currently considered separated species. In these melting pot areas, fine-scale ecological differentiation is likely the only force opposing panmixia in otherwise highly similar organisms. In this study, we focus on six Polynesian Pterodroma species currently found on Motu Nui, a protected islet offshore of Rapa Nui (Easter Island), four of which have likely extended their breeding range to that island recently. To understand the fine-scale interaction between these closely-related species in their new contact zone, we used an integrative approach combining ecological and genetic methods, including morphometric, bioacoustics, stable isotope niche reconstruction, breeding site characterisation, phenology traits, and both nuclear and mitochondrial DNA markers. We found that significant amounts of gene flow occur across what is currently considered species boundaries, sometimes questioning the relevance of the accepted species classification. Interestingly, our results indicate that multivariate ecological distance between individuals in a group of closely related species (P. alba, P. atrata, P. heraldica, and P. neglecta) is a relevant predictor of gene flow intensity, while more distant species such as P. ultima and P. nigripennis seem to maintain reproductive isolation. Thus, the case of Pterodroma petrels supports the idea that incomplete allopatric speciation processes may be halted or even reversed on a secondary contact zone. Beyond their direct taxonomical relevance, our results underline the importance of considering fine ecological structures for biodiversity mapping and conservation policies.
A multimethod approach for building climate literacy and a climate portal in the context of spatial regional planning in northern Patagonia
(JOURNAL OF ENVIRONMENTAL MANAGEMENT, 2025-06) Pineda, CP.; Salazar, A.; Acuña, MP.; Melgar, DO.; Sepúlveda, ME.; Bravo, F.
Integrating climate change considerations into planning at the subnational level is imperative for effective adaptation and risk reduction. Increased climate literacy among planners, supported by tools like climate portals can help this integration. This paper presents our approach to conveying a reasonable level of climate literacy and co-developing an online portal that provides useable climate information to planners. The approach was implemented in Northern Patagonia in collaboration with a Regional Government in preparation for their firstever Land-Use Regional Plan. Our findings show that planners lack explicit experience in integrating climate considerations into planning but possess significant awareness of climate impacts. While national climate change assessments help identifying critical adaptation priorities, a coproduction approach was still needed for developing region-specific actionable climate information. By implementing the proposed multi-method approach, including interviews and simulated planning exercises, key features were identified and achieved: a learning process, through an interdisciplinary team, should be in place to promote usage, climate data must be at the relevant scale, contextual information should be included, the portal must be interactive so planners may incorporate their knowledge, and, since climate data can be understood in different ways, planning objectives can contextualize different interpretations. Hands-on workshops, integral to the co-production process, enhanced planners' climate literacy by fostering practical understanding and use of climate indices. This collaborative approach highlights how tailored climate tools may bridge the gap between science and planning, providing critical support for effective climate adaptation.
Adaptive plasticity to drought of Grime's CSR strategies
(WILEY, 2023/11/01) Escobedo Victor M., Molina-Montenegro Marco A., Salgado-Luarte Cristian, Stotz Gisela C., Gianoli Ernesto
Grime's strategies (competitor, stress tolerator, ruderal, CSR) represent viable trait combinations with which species deal with environmental conditions. CSR strategies are broadly used to understand plant adaptation to the environment, yet their plastic responses have received little attention. A globally-calibrated tool (StrateFy) estimates CSR strategies using specific leaf area (SLA), leaf dry matter content (LDMC) and leaf area (LA) data, but these three traits can hardly characterise whole-plant responses to the environment individually. CSR strategies reflect tradeoffs among growth, survival and reproduction, at both leaf and whole-plant levels, thus integrating several functions. We hypothesised that CSR strategies and the three constituent traits would show independent plasticity patterns, and that CSR strategies would be more likely to show adaptive responses, i.e. to fit expected functional responses to environmental gradients. We compared phenotypic plasticity to drought in single traits (SLA, LDMC and LA) with the integrated plasticity of the resulting CSR strategy. The study species was the invasive plant Mesembryanthemum crystallinum, which is distributed in arid and semiarid Chile. We found that trait plasticity was rather idiosyncratic and contrary to what would be expected from a functional adjustment to drought: LDMC did not change (expected response: increase) and SLA increased (expected response: decrease). Conversely, plastic responses of CSR strategy and LA were consistent with functionally adaptive responses to drought in all populations: S-strategy increased, while C-strategy and LA decreased. We advocate the use of Grime's CSR theory as an integrative approach to further our understanding of adaptive plasticity in plants.
Age-driven structural characteristics relate to epigeal arthropod communities in olive agroecosystems of the Atacama Desert
(AGRICULTURE ECOSYSTEMS & ENVIRONMENT, 2025-06-15) Wallberg, BN.; Pizarro-Araya, J.; Alfaro, FM.; Calderón, JE.; Loayza, AP.
Intensive agriculture has led to a significant global decline of biodiversity. However, agroecosystems like olive groves can serve as biodiversity refuges, especially in arid environments, by acting as resource islands that promote the persistence of multiple species, including arthropods. The structural complexity and productivity of olive groves typically increase with age, enhancing their ability to sustain high biodiversity. In this study, we examined how epigeal arthropod diversity patterns vary across olive orchards of different ages in the Huasco Valley of Chile's Atacama Desert. We hypothesized that older olive orchards, with greater structural complexity and productivity, would harbor higher arthropod abundance, diversity, and distinct community compositions than a younger olive orchard. To test this hypothesis, we sampled epigeal arthropods in three olive orchards of different ages (young, intermediate, and centennial) using pitfall traps and characterized each orchard's structure and productivity (NDVI). Our findings indicate that olive orchard age is related to arthropod composition and abundance but not diversity. Young and intermediate olive orchards had higher arthropod abundance, dominated by isopods and hymenopterans, while entomophthorans and mites predominated in the centennial orchard. Each orchard harbored a unique arthropod community, with NDVI being a key factor in the centennial orchard, dry weed biomass in intermediate orchards, and leaf litter in young groves. These results suggest that the structural characteristics associated with olive orchard age play a crucial role in shaping arthropod communities in arid environments, highlighting the importance of habitat management within agroecosystems for promoting biodiversity.
An exotic plant species indirectly facilitates a secondary exotic plant through increased soil salinity
(SPRINGER, 2023/08/01) de la Cruz Henry J. J., Salgado-Luarte Cristian, Stotz Gisela C. C., Gianoli Ernesto
Indirect facilitation among exotic species may promote their establishment on ecosystems, causing biodiversity losses. However, few experimental studies have identified the mechanisms underlying the indirect facilitation among exotic species. In central-northern Chile, Mesembryanthemum crystallinum (Aizoaceae) is an exotic halophyte that increases soil salinity, while M. nodiflorum is another exotic halophyte -currently less dominant- that often co-occurs with M. crystallinum. In this study, we evaluated the indirect facilitation of M. nodiflorum by M. crystallinum which was mediated by the suppression of salt-susceptible native competitors via increased soil salinity. We further determined the relationship between salt-tolerance traits and the outcome of competitive interactions in saline soil. We included two native Asteraceae plants co-occurring with these Mesembryanthemum species: the -highly probable- salt-susceptible Helenium urmenetae and the salt-tolerant Amblyopappus pusillus. We combined field co-occurrence surveys with greenhouse germination and competition experiments. The Mesembryanthemum species tended to co-occur, which suggests facilitation. Further, the salinity level found under M. crystallinum significantly decreased germination and performance of H. urmenetae, but not of M. nodiflorum and A. pusillus. Accordingly, when in competition, the increased salinity counteracted the negative effect of H. urmenetae on M. nodiflorum biomass, giving M. nodiflorum a competitive advantage. These patterns were associated with decreased specific leaf area and crassulacean acid metabolism expression in M. nodiflorum. In contrast, A. pusillus and M. nodiflorum maintained a neutral interaction regardless of salinity. Overall, our results suggest that M. crystallinum, by increasing soil salinity, may reduce the performance of salt-susceptible competitors, indirectly facilitating the establishment of M. nodiflorum.
Ancient fires enhance Amazon forest drought resistance
(FRONTIERS MEDIA SA, Maynard Daniel S.) Vedovato Laura B., Carvalho Lidiany C. S., Aragao Luiz E. O. C., Bird Michael, Phillips Oliver L., Alvarez Patricia, Barlow Jos, Bartholomew David C., Berenguer Erika, Castro Wendeson, Ferreira Joice, Franca Filipe M., Malhi Yadvinder, Marimon Beatriz, Marimon Junior Ben Hur, Monteagudo Abel, Oliveira Edmar A., Pereira Luciana O., Pontes-Lopes Aline, Quesada Carlos A., Silva Camila V. J., Espejo Javier Silva E., Silveira Marcos, Feldpausch Ted R.
Drought and fire reduce productivity and increase tree mortality in tropical forests. Fires also produce pyrogenic carbon (PyC), which persists in situ for centuries to millennia, and represents a legacy of past fires, potentially improving soil fertility and water holding capacity and selecting for the survival and recruitment of certain tree life-history (or successional) strategies. We investigated whether PyC is correlated with physicochemical soil properties, wood density, aboveground carbon (AGC) dynamics and forest resistance to severe drought. To achieve our aim, we used an Amazon-wide, long-term plot network, in forests without known recent fires, integrating site-specific measures of forest dynamics, soil properties and a unique soil PyC concentration database. We found that forests with higher concentrations of soil PyC had both higher soil fertility and lower wood density. Soil PyC was not associated with AGC dynamics in non-drought years. However, during extreme drought events (10% driest years), forests with higher concentrations of soil PyC experienced lower reductions in AGC gains (woody growth and recruitment), with this drought-immunizing effect increasing with drought severity. Forests with a legacy of ancient fires are therefore more likely to continue to grow and recruit under increased drought severity. Forests with high soil PyC concentrations (third quartile) had 3.8% greater AGC gains under mean drought, but 33.7% greater under the most extreme drought than forests with low soil PyC concentrations (first quartile), offsetting losses of up to 0.68 Mg C ha(-1)yr(-1) of AGC under extreme drought events. This suggests that ancient fires have legacy effects on current forest dynamics, by altering soil fertility and favoring tree species capable of continued growth and recruitment during droughts. Therefore, mature forest that experienced fires centuries or millennia ago may have greater resistance to current short-term droughts.
Application of Vacuum and Convective Drying Processes for the Valorization of Pisco Grape Pomace to Enhance the Retention of its Bioactive Compounds
(2024/05/01) Poblete Jacqueline; Quispe-Fuentes Issis; Aranda Mario; Vega-Galvez Antonio
PurposeThe pisco produced in Chile is a distillate from pisco grape varieties, which generates a large amount of grape pomace. However, with the growing interest in reducing the environmental impact and converting these residues into novel by-products, the research and their evaluation in each stage can contribute significantly to ensuring their recovery. This study evaluated the kinetics of vacuum and convective drying from grape pomace at different temperatures and the influence on the retention of polyphenolic compounds and antioxidant activity as scalable alternatives for agro-industry.MethodsThe pisco grape pomace was dried by two drying methods at different temperatures: Vacuum drying (50-100 degrees C
Aridity Niche and Species Traits Mediate the Global Vulnerability of Passerine Birds
(GLOBAL CHANGE BIOLOGY, 2025-06) Petit, M.; Sayol, F.; Weideman, C.; Bertin, A.
Biodiversity is experiencing an unprecedented crisis, with intensifying global aridity representing a critical driver of species extinction. However, the extent to which species' preferences for specific aridity conditions and their tolerance to a range of aridity conditions influence their vulnerability remains poorly understood. Using data from 5558 passerine bird species, we examined how aridity niche affects current and projected extinction risks and whether these relationships are influenced by other ecological and life-history traits altering species persistence. Bayesian models revealed significant impacts of aridity niche position and breadth on both current and projected extinction risks, with these effects varying according to other species traits. Overall, aridity niche interacted with a wider range of traits for projected extinction risk than for current extinction risk, indicating a broader array of species requiring conservation attention in the future. Our results identified three key risk groups: (1) species preferring humid conditions, (2) species confined to arid zones with small clutch sizes, and (3) species with narrow aridity breadth and with low habitat breadth, short generation length, an omnivorous diet, and a full migrant strategy. By identifying passerine birds most at risk, our study offers critical insights for prioritizing conservation actions, guiding both geographic focus and the identification of species requiring more attention under the ongoing climate change.
Assessing Groundwater Potential in a Mid-Mountain Dryland Area of North-Central Chile through Geospatial Mapping
(2023/08/01) Deformes Jose Miguel; Nunez Jorge; Fairley Jerry P.; Arumi Jose Luis; Oyarzun Ricardo
This study utilized the Random Forest (RF) algorithm to assess groundwater potential (GWP) in the mid-mountain region of the Coquimbo region, north-central Chile. A comprehensive evaluation of twenty-one factors, primarily derived from Digital Elevation Models (DEM) and satellite data, was conducted against a database of 3822 groundwater discharge points. The majority of them consisted of shallow wells with relatively low yields. The main objective was to develop a groundwater potential (GWP) map for the study area. Among the factors considered, six variables, including two anthropogenic factors (distance to roads and presence of agricultural communities) and four natural factors (slope, elevation, concavity, and ruggedness index), were identified as the most influential indicators of GWP. The RF approach demonstrated excellent performance, achieving an Area Under the Curve (AUC) value of 0.95, sensitivity of 0.88, specificity of 0.86, and kappa coefficient of 0.74 in the test set. The majority of the study area exhibited low GWP, while only 14% of the area demonstrated high or very high GWP. In addition to providing valuable guidance for future hydrogeological investigations in the region, the GWP map serves as a valuable tool for identifying the areas that are most vulnerable to water shortages. This is particularly significant, as the region has been severely affected by extended drought, making water supply a critical concern.
Conservation efforts in need of survey improvement in epigean beetles from the Atacama coast, Chile
(ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD, 2023/07/01) Pizarro-Araya Jaime, Villalobos Elizabeth V., Alfaro Fermin M., Moreira-Munoz Andres
The Atacama desert's southern margin includes a poorly explored area of high biotic value with natural areas that are crucial for diversity and conservation. We used pitfall traps to study epigean beetles across 17 sites located along the coast between the Paposo Norte Natural Monument and the Paposo Priority Site. We recorded a total of 3,237 epigean beetles specimens, belonging to 26 families and 97 species. The most well represented families in terms of richness were Curculionidae and Tenebrionidae, and most of the remaining families were represented by fewer than five species. The rarefaction analysis showed that the sampling effort was low, sug-gesting the presence of a hidden and underestimated diversity in the area under study. The ordination analysis showed a clear correlation between elevation and the epigean beetles assemblage, but richness was concentrated in shrubland environments within the Paposo Priority Site and consisted of a large number of rare species (singletons) and species restricted to a few sites of this coastal strip. The high richness estimated for the study area, stress an urgent need to include these units under governmental conservation programs aimed at tackling the multiple threats identified in these fragile arid coastal ecosystems.
Conservation efforts in need of survey improvement in epigean beetles from the Atacama coast, Chile
(2023/07/01) Pizarro-Araya Jaime; Villalobos Elizabeth V.; Alfaro Fermin M.; Moreira-Munoz Andres
The Atacama desert's southern margin includes a poorly explored area of high biotic value with natural areas that are crucial for diversity and conservation. We used pitfall traps to study epigean beetles across 17 sites located along the coast between the Paposo Norte Natural Monument and the Paposo Priority Site. We recorded a total of 3,237 epigean beetles specimens, belonging to 26 families and 97 species. The most well represented families in terms of richness were Curculionidae and Tenebrionidae, and most of the remaining families were represented by fewer than five species. The rarefaction analysis showed that the sampling effort was low, sug-gesting the presence of a hidden and underestimated diversity in the area under study. The ordination analysis showed a clear correlation between elevation and the epigean beetles assemblage, but richness was concentrated in shrubland environments within the Paposo Priority Site and consisted of a large number of rare species (singletons) and species restricted to a few sites of this coastal strip. The high richness estimated for the study area, stress an urgent need to include these units under governmental conservation programs aimed at tackling the multiple threats identified in these fragile arid coastal ecosystems.
Correlation of plasticities to drought and shade: implications for environmental niche overlap in drylands
(WILEY, 2024/03/01) Escobedo Victor M., Rios Rodrigo S., Salgado-Luarte Cristian, Gianoli Ernesto
Phenotypic plasticity can increase the extent of the environmental gradient occupied by a species (niche breadth) and modify the portion of niche space shared among co-occurring species (niche overlap). Thus, phenotypic plasticity may play a role in community assembly processes. Given that plants deal with a multivariate environment, and that functional traits are often correlated, plastic responses to different environmental factors are likely correlated. However, the implications of correlations of plasticities for niche overlap remain unexplored. Here, we present and evaluate a conceptual framework that links correlations of plasticities and niche overlap patterns among co-occurring plant species. We specifically tested in an arid shrubland whether positive, negative, or null correlations between plasticity to light and water availability would be associated with patterns of high, low, or random niche overlap, respectively. Field data identified light and water availability as key factors shaping herbaceous plant community structure. We estimated species' niche breadth and niche overlap using two-dimensional kernel-density estimations (NOK) and standardised effect sizes of Pianka's niche overlap index (OSES). We measured phenotypic plasticity to light and water availability in the six most abundant species in a greenhouse experiment. We used the plasticity index (PI) to test 1) the relationship between plasticity to light and water availability, and 2) the association between overall plasticity (average PI across traits) and niche breadth. We found a positive relationship between plasticity to light and water availability. Increased overall plasticity was associated with a broader niche breadth. Both NOK and OSES estimations indicated a significant niche overlap pattern. Results supported one of the predictions of our conceptual framework: that a positive correlation of plasticities would lead to increased niche overlap. The verified conceptual framework broadens our understanding of the role of phenotypic plasticity in plant community coexistence.
Dispossession and governance: The invisible role of indigenous peoples in protected natural areas in Chile
(2023/12/01) Huaiquimilla-Guerrero Katherine; Moscote-Guerra Jeimy; Ramirez-Rivera Sebastian; Duhalde-Correa Luciano A.; Peralta-Scholz Maria Jose; Silva Fernanda Orellana; Plaza Veronica; Barrera Adrian Sanhueza; Squeo Francisco A.; Gaymer Carlos F.
At the international level, the progressive recognition of indigenous peoples and their customary rights in leg-islative tools has established new guidelines for the conservation of natural resources in protected areas (PAs). The indigenous peoples (IPs) in Chile who suffered the dispossession of ancestral areas after the declaration of PAs, have demanded their inclusion and participation based on the legislative tools available. Via the available scientific, institutional and gray literature, we identified seven ways in which IPs contribute to and participate in the protection of biodiversity, conservation and sustainability of natural resources in marine and terrestrial ecosystems in Chile: resistance or defense of ancestral areas, biocultural conservation, sustainable practices, participation in consultation, promotion of area creation, development of management plans, and management, comprising participation in administration, co-administration or co-management. Sixty percent of IPs participate in the management of 7.3% of Chile's PAs. Overall, our results show that the Rapanui and Kawashkar peoples participate mostly in the co-management of 729,439 km2 and 668 km2 of MPAs, respectively. The Aymara and Atacamen similar to o peoples lead the management of TPAs in the north of Chile, with 1378 km2 and 872.36 km2 , respectively. The Mapuche people, with a higher population density, participate in both environments, leading the administration of maritory with 3475.98 km2 of Marine and Coastal Areas for Indigenous Peoples (MCAIPs). The participation of the remaining peoples is limited. Advancing the recognition and role of IP in the protection of nature via a shared biocultural governance is a challenge for the Chilean State.
Diversification trajectories and paleobiogeography of Neogene chondrichthyans from Europe
(CAMBRIDGE UNIV PRESS, 2023/05/01) Villafana Jaime A. A., Rivadeneira Marcelo M. M., Pimiento Catalina, Kriwet Juergen
Despite the rich fossil record of Neogene chondrichthyans (chimaeras, sharks, rays, and skates) from Europe, little is known about the macroevolutionary processes that generated their current diversity and geographical distribution. We compiled 4368 Neogene occurrences comprising 102 genera, 41 families, and 12 orders from four European regions (Atlantic, Mediterranean, North Sea, and Paratethys) and evaluated their diversification trajectories and paleobiogeographic patterns. In all regions analyzed, we found that generic richness increased during the early Miocene, then decreased sharply during the middle Miocene in the Paratethys, and moderately during the late Miocene and Pliocene in the Mediterranean and North Seas. Origination rates display the most significant pulses in the early Miocene in all regions. Extinction rate pulses varied across regions, with the Paratethys displaying the most significant pulses during the late Miocene and the Mediterranean and North Seas during the late Miocene and early Pliocene. Overall, up to 27% and 56% of the European Neogene genera are now globally and regionally extinct, respectively. The observed pulses of origination and extinction in the different regions coincide with warming and cooling events that occurred during the Neogene globally and regionally. Our study reveals complex diversity dynamics of Neogene chondrichthyans from Europe and their distinct biogeographic composition despite the multiple marine passages that connected the different marine regions during this time.
Ecological uniqueness across multiple levels of biodiversity in a Chilean watershed
(SPRINGER, 2024/06/01) Borquez Jessica, Sampertegui Sandra, Wallberg Britt N., Coral-Santacruz Diana, Ruiz Victor H., Samollow Paul B., Gouin Nicolas, Bertin Angeline
To effectively address biodiversity loss, it is essential to prioritize conservation efforts by identifying areas of high conservation value. Ecological uniqueness is a valuable metric for this purpose that decomposes beta diversity into local contributions to beta diversity (LCBD), thereby measuring the contribution of each site within a region to overall biodiversity variation. LCBD has been used extensively to evaluate ecological uniqueness from community composition data, but biodiversity is a multifaceted concept, and community-based ecological uniqueness may not capture the full range of ecological uniqueness occurring at other levels of biological organization. We investigated ecological uniqueness estimates derived from community and species population levels in a watershed of south-central Chile and analyzed their responses to water and habitat quality variables. Ecological uniqueness was estimated at the community level from fish and macroinvertebrate assemblages and at the population level using genetic and morphological data gathered for two invertebrates, the gastropod Chilina dombeiana and the water bug Aquarius chilensis. Our results revealed low spatial congruence between the levels of ecological uniqueness calculated for these different biodiversity components, with mismatches occurring among sites with high LCBD values. Water and habitat quality were major drivers of beta diversity in this watershed, accounting for 43.8% to 74.3% of the spatial variation in LCBDs, and their effects differed among the ecological uniqueness estimates. Overall, our results underscore the idiosyncratic nature of ecological uniqueness metrics, emphasizing the importance of using multiple components of biodiversity to guide conservation actions.
Effects of land cover and habitat condition on the bird community along a gradient of agricultural development within an arid watershed of Chile
(ELSEVIER, 2023/10/15) Petit Mariangeles, Celis Cristian, Weideman Craig, Gouin Nicolas, Bertin Angeline
Agricultural activities are a major cause of change in avifauna, frequently resulting in diminished diversity and biotic homogenization, and ultimately compromising ecosystem functioning and resilience. Arid ecosystems, which provide habitat for numerous native and endemic bird species, are vulnerable to global change and valuable in predicting future ecosystem shifts in regions undergoing aridification as a result of climate change. However, the impacts of agriculture on bird communities in arid ecosystems are understudied. Here, we evaluate these impacts in the arid Limari watershed in north-central Chile, a region that has experienced extensive land use conversion to agriculture over the past 50 years. Specifically, we investigated current spatial patterns of avian beta diversity and the impact of landscape context on this diversity facet. Moreover, we evaluated how bird species respond to land cover and habitat conditions and the role of specific bird traits in this regard. To achieve this, we evaluated taxonomic and functional beta diversity across 26 sites distributed along a gradient of agricultural development, applied a beta diversity decomposition procedure, and carried out hierarchical joint species distribution modeling. Our study revealed high taxonomic but low functional beta diversity of the avifauna in the Limari watershed, potentially indicative of past functional homogenization. Contrary to our initial expectations, present agricultural practices did not decrease beta diversity. While human-related landscape elements and agricultural features mostly had neutral or positive effects on bird occurrence, they negatively affected endemic species and certain bird traits related to diet and habitat. Riparian vegetation cover and quality, unrelated to agricultural and urban development, emerged as key factors structuring the regional bird community, and influenced beta diversity. Our results underscore the profound influence of land use change on the avian community in this arid region and the vital role of riparian ecosystems in this regard. Balancing conservation objectives with agricultural development is key to ensuring both the persistence of several functional groups in the region as well as the ecosystem services they provide.
Effects of land cover and habitat condition on the bird community along a gradient of agricultural development within an arid watershed of Chile
(2023/10/15) Petit Mariangeles; Celis Cristian; Weideman Craig; Gouin Nicolas; Bertin Angeline
Agricultural activities are a major cause of change in avifauna, frequently resulting in diminished diversity and biotic homogenization, and ultimately compromising ecosystem functioning and resilience. Arid ecosystems, which provide habitat for numerous native and endemic bird species, are vulnerable to global change and valuable in predicting future ecosystem shifts in regions undergoing aridification as a result of climate change. However, the impacts of agriculture on bird communities in arid ecosystems are understudied. Here, we evaluate these impacts in the arid Limari watershed in north-central Chile, a region that has experienced extensive land use conversion to agriculture over the past 50 years. Specifically, we investigated current spatial patterns of avian beta diversity and the impact of landscape context on this diversity facet. Moreover, we evaluated how bird species respond to land cover and habitat conditions and the role of specific bird traits in this regard. To achieve this, we evaluated taxonomic and functional beta diversity across 26 sites distributed along a gradient of agricultural development, applied a beta diversity decomposition procedure, and carried out hierarchical joint species distribution modeling. Our study revealed high taxonomic but low functional beta diversity of the avifauna in the Limari watershed, potentially indicative of past functional homogenization. Contrary to our initial expectations, present agricultural practices did not decrease beta diversity. While human-related landscape elements and agricultural features mostly had neutral or positive effects on bird occurrence, they negatively affected endemic species and certain bird traits related to diet and habitat. Riparian vegetation cover and quality, unrelated to agricultural and urban development, emerged as key factors structuring the regional bird community, and influenced beta diversity. Our results underscore the profound influence of land use change on the avian community in this arid region and the vital role of riparian ecosystems in this regard. Balancing conservation objectives with agricultural development is key to ensuring both the persistence of several functional groups in the region as well as the ecosystem services they provide.
Enhancement of the catalytic activity of Carbonic Anhydrase by covalent immobilization on Magnetic Cellulose Crystals
(2023/02/01) Rodriguez Liliana Castro; Restrepo-Sanchez Nora; Pelaez Carlos; Bernal Claudia
In this study, Magnetic Cellulose Crystals (MCCs) are modified, characterized and used to immobilization of Bovine Carbonic Anhydrase (BCA). BCA enzyme was covalently attached via glutaraldehyde to two MCCs materials: a magnetic cellulose I polymorph (MCC-I) and a mixture of magnetic cellulose I and II polymorphs (MCCI-II). The esterase activity of BCA immobilized into MCC-I (BCA-MCC-I) and MCC-I-II (BCA-MCC-I-II) was 228 and 318 % greater than the free enzyme, respectively. At 60 degrees C, BCA-MCC-I-II maintained up to 80 % of its initial activity, after 48 h. The activity of BCA-MCC-I was higher in comparison with the other derivatives at acid pH, conserved the 80 % of initial activity after 48 h. The high activity and stability of achieved biocatalysts are considering a great starting step to develop green strategies for CO2 mitigation, using eco-friendly materials, like cellulose. These findings are expected to impact enzyme-based CO2 transformation strategies and contribute to mitigate global warming.
Explainable Artificial Intelligence in Hydrology: Interpreting Black-Box Snowmelt-Driven Streamflow Predictions in an Arid Andean Basin of North-Central Chile
(2023/10/01) Nunez Jorge; Cortes Catalina B.; Yanez Marjorie A.
In recent years, a new discipline known as Explainable Artificial Intelligence (XAI) has emerged, which has followed the growing trend experienced by Artificial Intelligence over the last decades. There are, however, important gaps in the adoption of XAI in hydrology research, in terms of application studies in the southern hemisphere, or in studies associated with snowmelt-driven streamflow prediction in arid regions, to mention a few. This paper seeks to contribute to filling these knowledge gaps through the application of XAI techniques in snowmelt-driven streamflow prediction in a basin located in the arid region of north-central Chile in South America. For this, two prediction models were built using the Random Forest algorithm, for one and four months in advance. The models show good prediction performance in the training set for one (RMSE:1.33, R2: 0.94, MAE:0.55) and four (RMSE: 5.67, R2:0.94, MAE: 1.51) months in advance. The selected interpretation techniques (importance of the variable, partial dependence plot, accumulated local effects plot, Shapley values and local interpretable model-agnostic explanations) show that hydrometeorological variables in the vicinity of the basin are more important than climate variables and this occurs both for the dataset level and for the months with the lowest streamflow records. The importance of the XAI approach adopted in this study is discussed in terms of its contribution to the understanding of hydrological processes, as well as its role in high-stakes decision-making.
Exploring the Causes of Multicentury Hydroclimate Anomalies in the South American Altiplano with an Idealized Climate Modeling Experiment
(ATMOSPHERE, 2025-06-20) Jara, IA.; Astudillo, O.; Salinas, P.; Torrez-Rodríguez, L.; Lampe-Huenul, N.; Maldonado, A.
Paleoclimate records have long documented the existence of multicentury hydroclimate anomalies in the Altiplano of South America. However, the causes and mechanisms of these extended events are still unknown. Here, we present a climate modeling experiment that explores the oceanic drivers and atmospheric mechanisms conducive to long-term precipitation variability in the southern Altiplano (18-25 degrees S; 70-65 W; >3500 masl). We performed a series of 100-year-long idealized simulations using the Weather Research and Forecasting (WRF) model, configured to repeat annually the oceanic and atmospheric forcing leading to the exceptionally humid austral summers of 1983/1984 and 2011/2012. The aim of these cyclical experiments was to evaluate if these specific conditions can sustain a century-long pluvial event in the Altiplano. Unlike the annual forcing, long-term negative precipitation trends are observed in the simulations, suggesting that the drivers of 1983/1984 and 2011/2012 wet summers are unable to generate a century-scale pluvial event. Our results show that an intensification of the anticyclonic circulation along with cold surface air anomalies in the southwestern Atlantic progressively reinforce the lower and upper troposphere features that prevent moisture transport towards the Altiplano. Prolonged drying is also observed under persistent La Ni & ntilde;a conditions, which contradicts the well-known relationship between precipitation and ENSO at interannual timescales. Contrasting the hydroclimate responses between the Altiplano and the tropical Andes result from a sustained northward migration of the Atlantic trade winds, providing a useful analog for explaining the divergences in the Holocene records. This experiment suggests that the drivers of century-scale hydroclimate events in the Altiplano were more diverse than previously thought and shows how climate modeling can be used to test paleoclimate hypotheses, emphasizing the necessity of combining proxy data and numerical models to improve our understanding of past climates.