Ciencias de la Tierra y Medioambientales
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Food habits of the Lesser grison Galictis cuja (Molina, 1782) in the Huasco coastal desert, Los Choros, northern Chile
(JOURNAL OF ARID ENVIRONMENTS, 2025-12) Zuleta-Ramos, C.; ZRau, JR.
The Lesser grison, Galictis cuja, is a carnivorous mammal widely distributed in South America. However, its conservation status and natural history are poorly understood throughout much of its range. In Chile, it is found in all regions of the country from deserts in the north to temperate rainforests in the south. This species is characterized as Rare in most of the habitats where it has been recorded. This study analyzed the diet of G. cuja in the Huasco coastal desert of the Coquimbo Region, northern Chile. Sixty-three fecal samples were collected in September 2010 (spring), which were then analyzed and categorized using keys and reference collections. Its diet was generalist, consisting of imago arthropods, larvae, and pupae, which represented 75 % of the prey consumed. Coleoptera of the family Tenebrionidae were the most frequently found trophic category in the diet. However, the Lesser grison also consumes wild rodents, which accounted for 25 % of its diet, with the Darwin leaf-eared mouse Phyllotis darwini (about 50 g) being the most frequent prey item. This suggests that their diet in this arid ecosystem is generalist, which could also be related to the resources available in a fluctuating environment.
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.
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.
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.
Isolation and Characterization of Polyunsaturated Fatty Acid-Rich Oil from Jumbo Squid (Dosidicus gigas) Viscera: Antioxidant Potential and Anticancer Activity on Colorectal Cancer Cells
(WASTE AND BIOMASS VALORIZATION, 2025-07) Quispe-Fuentes, I.; Valenzuela, P.; Roco, T.; Pérez-Won, M.; Espinoza, J.; Bernal, G.; Bernal, C.; Martinez, R.
The global impact of residues resulting from fishing processing has generated the need to develop sustainable processes, find additional potential of raw materials, and provide alternatives for their recovery of potentially valuable by-products. On the other hand, colorectal cancer (CRC) is the second leading cause of cancer death worldwide and needs novel and more effective treatments. In this study, we extracted and characterized oil from Jumbo squid hepatopancreas and evaluated its antioxidant potential and antiproliferative activity. The oil recovered from the Jumbo squid production process has characteristics that meet international standards. PUFA-rich oil from Jumbo squid hepatopancreas showed high concentrations of EPA/DHA (about 42% of the total fatty acids) and antioxidant potential. The antiproliferative activity evaluated on colorectal cancer cells, HCT116, showed activity against the tumor cells, representing the first evidence for a potential anticancer application. This research proposes a sustainable strategy for achieving a circular bioeconomy by recovering oil from jumbo squid viscera, offering alternatives for valorizing this bioproduct.
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.
Participatory scenario planning for sustainable development in San Pedro de Atacama, Chile : Addressing water scarcity and cultural preservation
(ENVIRONMENTAL DEVELOPMENT, 2026-01) Salas-Bravo, S.; Bodini-Salas, A.; Araya-Pinones, A.
Global changes present significant challenges for development, particularly for Indigenous communities, owing to their economic and social impacts. This study explored participatory scenarios for the sustainable development of San Pedro de Atacama, over time scales of 10, 30, 50, and 100 years. Using a mixed-methods approach (quan -> QUAL), the research engaged key stakeholders, with an emphasis on the local Indigenous Lican Antai population, to identify critical pressures and events influencing the region's future. The findings reveal deep concerns regarding water scarcity, climate change, expanding lithium mining, increased tourism, and loss of Indigenous cultural identity. Two main scenarios have emerged: Social Water Management and Social Distrust. In both scenarios, future development could result in a significant loss of historical and cultural roots and deterioration of biodiversity. Water scarcity has been identified as a critical factor catalyzing potential events, such as migration, population reduction, the decline of agriculture, and the emergence of new water management initiatives. This study proposes six strategic axes for sustainable development: community unity, multi-perspective tourism planning, territorial management, trust-building, leadership strengthening, and conflict transformation. Successful implementation requires coordination with higher levels of governance and efforts to incorporate traditional and Indigenous knowledge into public policies and management strategies. This pioneering study offers crucial insights into community perceptions of climate vulnerability and pathways for sustainable development in the Atacama Desert region.
Treatment of landfill leachate by combined use of ultrasound and photocatalytic process using fly ash as catalyst
(2024/01/01) Poblete Rodrigo; Cortes Ernesto; Perez Norma; Rodriguez C. A.; Luna-Galiano Yolanda
Advanced oxidation processes, such as sonophotocatalysis and photocatalysis, have been proven to be interesting alternatives for the effective treatment of old landfill leachates. Since there is no specific information about which parameters help to improve the treatment efficiency when using fly ash (FA) in a sonophotoreactor, this research focuses on evaluating the use of an ultrasound process (US) combined with a photo-Fenton process, with FA as a catalyst for the first time. The removals of colour, chemical oxygen demand (COD), and aromatic compounds (UV 254) present in landfill leachates were studied using a factorial design, where the effect of different loads of FA (1, 1.5, and 2 g FA/L), pH (pH = 3, 6, and 8.9), and US frequency irradiation (576, 864, and 1138 kHz) on the efficiency of photo-Fenton was evaluated. The highest removals of COD (40.7%), colour (36.8%), and UV 254 (50.8%) were achieved adjusting the pH to 3, adding 2 g of FA/L, and applying 576 kHz of US frequency. It was found that pH is the parameter that has the highest effect on pollutant removal (95% confidence level). In addition, the removals of COD, colour, and UV 254 increased at lower pH values and US frequency. Also, the presence of Fe2O3, SiO2, and TiO2 in the FA under UV irradiation and ultrasound process, improved the removal of complex organic matter present in the landfill leachate, where HO center dot was the most important radical.
The dynamics of arsenic and copper in solid and aqueous phases in reactive confluences receiving acid drainage: The role of turbidity and particle size*
(2023/06/15) Diaz J. A.; Castillo D.; Oyarzun R.; Briso A.; Montecinos M.; Pasten P.
The fate of suspended solids in aqueous systems enriched with copper (Cu) and arsenic (As) is still poorly understood, especially in mildly acidic streams with natural turbidity. This study integrated field, laboratory, and modeling to determine how turbidity, particle size distribution, and the partition of Cu and As interact in two model river confluences in an Andean watershed (upper Elqui, North-Central Chile). The mildly acidic Toro River (4<5
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.
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.
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.
Linnean and Wallacean shortfalls in the knowledge of arthropod species in Chile: Challenges and implications for regional conservation
(2023/05/01) Vergara-Asenjo Gerardo; Alfaro Fermin M.; Pizarro-Araya Jaime
Despite global efforts to identify and classify species to improve biodiversity baselines, there still remains large knowledge shortfalls that affect our understanding of the functioning of ecosystems and the design of effective conservation practices. Using the results of the first ongoing large-scale biodiversity inventory for Chile which has already recorded ca. 1,800 species and discovered 87 new species of arthropods, we explore and discuss taxonomy (Linnean) and distribution (Wallacean) shortfalls that preclude large-scale knowledge of arthropod biodiversity for one of the lesser studied groups in the world - the arthropods. Linnean shortfalls are mainly associated with the lack of funding of monitoring and inventory initiatives and the bias towards most charismatic or umbrella species, which in turn trigger effects on the experts' availability, recruitment of taxonomists in research centers, journal impact factors, as well as the availability of scientific collections of type specimens. Instead, Wallacean shortfalls are related to accessibility to remote areas, and the spatial and temporal resolution of sampling efforts. Based on our results and literature review, we discuss the findings and also propose a novel conceptual framework aimed to reduce data gaps and support biodiversity conservation policies, particularly in developing countries. The framework has three main components: (1) the ecosystems, their species, and the threats
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
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.
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.
Use of copper sheet in a solar photo-Fenton-like process applied in the treatment of landfill leachate
(2023/05/01) Poblete Rodrigo; Rodriguez Carlos Anibal; Carrasco Claudia; Herrera Jose; Salazar-Gonzalez Ricardo
It is known that copper can be used as catalyst in photo-Fenton-like process
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.
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.