DSpace Angular :: Browsing by Author "Vergara, Pablo M."

Browsing by Author "Vergara, Pablo M."

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An island biogeography approach for understanding changes in compositional similarity at present scenario of biotic homogenization
(ELSEVIER, 2011) Vergara, Pablo M.; Pizarro, Jaime; Castro, Sergio A.
Local extinction of native species and colonization of non-native species are commonly invoked as responsible for changes in species similarity among biotas of different regions. In this study we used a model of species similarity between islands to assess the emergent, and unexplored, effects of changes in colonization by native species, extinction of non-native species, and propagule pressure on species similarity among insular communities. The model predicts that extinction probability of endemic species has a positive but asymptotic effect on species similarity, which is exacerbated by increasing colonization and reducing extinction of non-native species. Species similarity tends to increase with increasing colonization probability by non-native species, however this effect may be reduced, or even reverted, when the islands are exposed to an elevated number of non-native species that are prone to extinction, high levels of endemic species loss, and an initially large number of native species shared between islands. Species similarity was positively affected by the propagule pressure rate of non-native species only when their colonization and extinction probabilities were large and small enough, respectively. A negative effect of propagule pressure rate can be caused by an increase in the pool size of non-native species, which involves the introduction of different species into different islands, promoting biotic differentiation between islands. Our results indicate that the interactions between colonization, extinction and species pool lead to nonlinear responses and unexpected scenarios of biotic change. In order to validate model predictions, future research programs should focus on understanding the dynamics on such complex meta-communities where coexist native, non-native and endemic species. (C) 2011 Elsevier B.V. All rights reserved.
Analyzing the Spatiotemporal Patterns of Forests Carbon Sink and Sources Between 2000 and 2019
(2022) Alaniz, Alberto J.; Carvajal, Mario A.; Marquet, Pablo A.; Vergara, Pablo M.; Meneses, Luis; Moreira-Arce, Dario
Here we present a global time-series of global forest above ground biomass from 2000 to 2019, analyzing spatiotemporal patterns of carbon balance, accounting for losses and gains. We generated a global Above-Ground Biomass (AGB) map for the year 2000 and assessed its correlation with different satellite products. We generated a multi-year analysis of AGB changes at the pixel level was generated, estimating carbon (C) loss and gain. Finally, we estimated the C losses due to forest clearing and wildfires analyzing their trends across biomes and countries. Our results show that the global mean annual loss was 2.88 +/- 0.33 PgC yr(-1), while global mean C gain was 2.95 +/- 0.43 PgC yr(-1), resulting in a neutral to sink behavior of -0.06 +/- 0.58 PgC yr(-1). The mean annual C loss by forest clearing was 1.04 +/- 0.03 PgC yr(-1), with an increasing trend of +0.03 +/- 0.01 PgC yr(-1). Eight biomes and 54 countries showed a significant increasing trend of C loss by forest clearing. Wildfires C losses reached 0.351 +/- 0.02 Pg C yr(-1), representing the 33.71% of forest clearing C losses. Boreal forest presented the highest C losses from wildfires, while significant increasing trends were evidenced in five biomes. We also find increasing trends of wildfire C loss in 20 countries while decreasing trends were identified in 10 countries. Our findings highlight the importance of designing strong policies to halt deforestation as agreed in the recent COP26 and provide information to identify priority areas to start implementing these policies in the short term.
Biodiversity and biogeography of birds in Pacific Mexico along an isolation gradient from mainland Chamela via coastal Marias to oceanic Revillagigedo Islands
(2012) Hahn, Ingo J.; Hogeback, Steffen; Roemer, Uwe; Vergara, Pablo M.
Following an isolation gradient in West-Mexico the avifauna of three study areas is investigated, on mainland reserve and two island groups. The avifaunas are described and analysed regarding species richness, environmental attributes, endemism, broader ecological niches, and brood status. The taxonomical composition is determined on different hierarchy levels. Most species records come from mainland Chamela (262), followed by the coastal Marias (191) and the oceanic Revillagigedos (148). Thereof 139 bird species breed in Chamela, 61 on Marias and only 29 on the Revillagigedos. In total, in the three study areas 364 species were recorded, which belong to 22 orders. On island groups generally less taxa per hierarchy level are present than on the mainland, especially on the remote Revillagigedos. Here, on average 1.7 species are found per genus, 2.2 genera per family, and 2.5 families per order. In the analysis of the taxonomical hierarchy relations to each other an isolation gradient is identified: from mainland Chamela via the coastal Marias to the oceanic Revillagigedos the degree of relatedness decreases on average. The results support the theoretical hypothesis that on islands closely related taxa tend to exclude each other and that one generalist tends to replace several specialists. Small ecological niches are often not occupied by specialist species on islands, but are used by generalists.
Climate-induced tree senescence leads to a transient increase in reproductive success of a large woodpecker species
(2022) Carvajal, Mario A.; Alaniz, Alberto J.; Vergara, Pablo M.; Hernandez-Valderrama, Carlos; Fierro, Andres; Toledo, Gisela; Gamin, Juan
Climate change-induced mortality of trees is a concerning phenomenon for global forest ecosystems. The rapid decay and death of long-lived trees can significantly impact forest dynamics, with effects that transmit through ecological networks, becoming more evident in organisms occupying high trophic levels, such as large and spe-cialized woodpecker species. However, understanding how populations of high trophic level species respond to climate change is still a challenge. In this study it was analyzed 32-year data of social groups of the Magellanic Woodpecker (Campephilus magellanicus) in North Patagonia, a region facing increasingly frequent droughts and increased temperatures. A positive trend in the size of woodpecker social groups as a response to climate-induced tree senescence was tested. A causal structural equation model examining climate-tree senescence-woodpecker relationships was used. Increasing nonlinear trends and positive interannual growth rates (>10%) for tree senescence and group size were found. Lowland forest sites had higher levels of tree senescence and more numerous social groups. The causal model supported the positive effect of mean temperature on tree senes-cence and the positive association of woodpeckers with tree senescence. These results provide evidence of a climate-induced increase in tree senescence that causes an increase in the size of woodpecker social groups. It is suggested that accelerated decay and mortality of trees in the northern Patagonian forests will decrease the stocks of deadwood in the long term, threatening the persistence of this large woodpecker species. (c) 2021 Elsevier B.V. All rights reserved.
Contaminant emissions as indicators of chemical elements in the snow along a latitudinal gradient in southern Andes
(NATURE RESEARCH, 2021) Pizarro, Jaime; Vergara, Pablo M.; Cerda, Sergio; Cordero, Raul R.; Castillo, Ximena; Rowe, Penny M.; Casassa, Gino; Carrasco, Jorge; Damiani, Alessandro; Llanillo, Pedro J.; Lambert, Fabrice; Rondanelli, Roberto; Huneeus, Nicolas; Fernandoy, Francisco; Alfonso, Juan; Neshyba, Steven
The chemical composition of snow provides insights on atmospheric transport of anthropogenic contaminants at different spatial scales. In this study, we assess how human activities influence the concentration of elements in the Andean mountain snow along a latitudinal transect throughout Chile. The concentration of seven elements (Al, Cu, Fe, Li, Mg, Mn and Zn) was associated to gaseous and particulate contaminants emitted at different spatial scales. Our results indicate carbon monoxide (CO) averaged at 20 km and nitrogen oxide (NOx) at 40 km as the main indicators of the chemical elements analyzed. CO was found to be a significant predictor of most element concentrations while concentrations of Cu, Mn, Mg and Zn were positively associated to emissions of NOx. Emission of 2.5 mu m and 10 mu m particulate matter averaged at different spatial scales was positively associated to concentration of Li. Finally, the concentration of Zn was positively associated to volatile organic compounds (VOC) averaged at 40 km around sampling sites. The association between air contaminants and chemical composition of snow suggests that regions with intensive anthropogenic pollution face reduced quality of freshwater originated from glacier and snow melting.
Defining corridors for movement of multiple species in a forest-plantation landscape
(2020) Pliscoff, Patricio; Simonetti, Javier A.; Grez, Audrey A.; Vergara, Pablo M.; Barahona-Segovia, Rodrigo M.
Forestry plantations of Pinus radiata, managed through clearcutting method, would offer resistance to the movement of native fauna among remnants of native forest. In this study, we evaluate the possibilities of establishing connectivity corridors for native fauna in a forest landscape dominated by P. radiata, focusing on seven species with some level of specialisation in the use of different land covers and that exhibit different movement strategies. We sampled presences and abundances using several types of sampling to determine the abundance and crossing edge probabilities for the ground-dwelling beetle Ceroglossus chilensis; the mesocarnivores Conepatus chinga, Lycalopex culpaeus and Leopardus guigna; the terrestrial frogs Eupsophus septentrionalis and Pleuroderma thaul, and the understory bird Pteroptochos castaneus. We use species distribution modelling and circuit theory to calculate connectivity for each species. Finally, a spatial priorization approach was applied to obtain two scenarios of least-cost corridors. The results show that species with more specific requirements such as L. guigna, P. castaneus, P. thaul and E. septentrionalis, are unlikely to move through clear cuttings and young plantations, but their movement is possible through adult pine plantations with understory. For species that are habitat generalists such as C. chinga and L. culpaeus plantations were suitable for movement. The management of forest plantations should use multi-taxa assessments in the design of biological corridors that allow the connection of forest fragments. (C) 2020 The Authors. Published by Elsevier B.V.
Effects of air pollution and weather on the initial COVID-19 outbreaks in United States, Italy, Spain, and China: A comparative study
(2023) Alaniz, Alberto J.; Carvajal, Mario A.; Carvajal, Jorge G.; Vergara, Pablo M.
Contrasting effects have been identified in association of weather (temperature and humidity) and pollutant gases with COVID-19 infection, which could be derived from the influence of lockdowns and season change. The influence of pollutant gases and climate during the initial phases of the pandemic, before the closures and the change of season in the northern hemisphere, is unknown. Here, we used a spatial-temporal Bayesian zero-inflated-Poisson model to test for short-term associations of weather and pollutant gases with the relative risk of COVID-19 disease in China (first outbreak) and the countries with more cases during the initial pandemic (the United States, Spain and Italy), considering also the effects of season and lockdown. We found contrasting association between pollutant gases and COVID-19 risk in the United States, Italy, and Spain, while in China it was negatively associated (except for SO2). COVID-19 risk was positively associated with specific humidity in all countries, while temperature presented a negative effect. Our findings showed that short-term associations of air pollutants with COVID-19 infection vary strongly between countries, while generalized effects of temperature (negative) and humidity (positive) with COVID-19 was found. Our results show novel information about the influence of pollution and weather on the initial outbreaks, which contribute to unravel the mechanisms during the beginning of the pandemic.
Environmental and biotic filters interact to shape the coexistence of native and introduced bees in northern Patagonian forests
(2023) Vergara, Pablo M.; Fierro, Andres; Carvajal, Mario A.; Alaniz, Alberto J.; Zorondo-Rodriguez, Francisco; Cifuentes, Maria C.; Castro, Sergio A.
Native and introduced species can coexist in rich ecosystems where competition for resources is less intense; however, native species can be excluded from suitable habitats hosting a high abundance of introduced species. To test these hypotheses, we estimated the probability of introduced bees (buff-tailed bumblebees and honeybees) to co-occur and dominate giant bumblebees in forested landscapes of northern Patagonia. We evaluated the effects of 29 remote-sensing variables of forest ecosystems on bee abundance using data from 56 landscapes. Then, we used a probabilistic Bayesian model to estimate the effects of the most important predictors of bee abundance on their co-occurrence and dominance probabilities. Introduced and native bees exhibited heterogeneous and scale-dependent responses to environmental conditions, with only six variables affecting their cooccurrence and dominance probabilities. A high maximum temperature was associated with both a decreased co-occurrence and an increased dominance of introduced bumblebees, and the opposed pattern was found for vegetation continuous fields, an index of canopy continuity. Similar responses were found for the co-occurrence probability of honeybees and giant bumblebees. Thus, species dominance and co-occurrence changed differently along environmental gradients, with co-occurrence increasing as native and introduced species become more abundant. A high dominance of introduced bees in unsuitable habitats suggests interspecific competition is strengthened as resources become scarcer, thus reinforcing the idea that abiotic and biotic filters interact with each other.
Fire Severity Causes Temporal Changes in Ground-Dwelling Arthropod Assemblages of Patagonian Araucaria-Nothofagus Forests
(2022) Zuniga, Alfredo H.; Rau, Jaime R.; Fierro, Andres; Vergara, Pablo M.; Encina-Montoya, Francisco; Fuentes-Ramirez, Andres; Jaksic, Fabian M.
Fire is one of the main drivers of anthropogenic disturbances in temperate forest ecosystems worldwide, with multiple effects spread across ecological networks. Nevertheless, the biodiversity effects of fire are poorly known for species-diverse groups such as arthropods. In this research, we used a burn gradient generated two and three years after a large fire event to assess how different levels of fire severity affect arthropod diversity in the forest with the main forest forming long-living tree species Araucaria araucana, in southern Chile. The species richness and abundance of arthropods among trophic guilds was estimated annually in four fire-severity levels. We found that arthropods responded differently to fire severity levels, depending on their trophic guilds and years after fire (two and three years after fire). During the second year after fire, zoophages, phytophages, and parasitoids were more diverse in areas with high fire severity within the second year after fire, as compared to those in areas with low severity or unburned stands. In the third year after fire, a change in this trend was observed, where the abundance of all groups dropped significantly, with positive changes in the diversity in zoophages, phytophages, polyphages and saprophages, which is more noticeable in sites with high severity. These results indicate that annual variation in environmental conditions triggers bottom-up cascading effects for arthropods. Forests stands severely impacted by fires support highly fluctuating and possibly unstable arthropod assemblages. Hence, restoration efforts should be focused on recovering microhabitat conditions in these stands to allow the persistence of arthropods.
Increasing importance of heat stress for cattle farming under future global climate scenarios
(2021) Carvajal, Mario A.; Alaniz, Alberto J.; Gutierrez-Gomez, Constanza; Vergara, Pablo M.; Sejian, Veerasamy; Bozinovic, Francisco
In the last decades, livestock species have been severely affected by heat stress because of increasing temperatures, which has threatened animal welfare and decreased production. Based on thermal comfort indices and ensemble climate projections, we analyzed the current and future global spatiotemporal patterns of the heat exposure of cattle in 10 agroclimatic zones. The results show that similar to 7% of the global cattle population is currently exposed to dangerous heat conditions. This percentage is projected to increase to similar to 48% before 2100 under a scenario of growing emissions. Tropical agroclimatic zones are expected to face an early increase in the exposure to intense heat before 2050. Heat exposure was negatively correlated with the socioeconomic variables, showing that poor and livestock-dependent tropical countries are the most affected. Our results demonstrate the near future consequences of heat stress on livestock, emphasizing the limited time available to implement effective abatement strategies. (C) 2021 Elsevier B.V. All rights reserved.
Latitude does not influence cavity entrance orientation of South American avian excavators
(OXFORD UNIV PRESS INC, 2021) Ojeda, Valeria; Schaaf, Alejandro; Altamirano, Tomas A.; Bonaparte, Bianca; Bragagnolo, Laura; Chazarreta, Laura; Cockle, Kristina; Dias, Raphael; Di Sallo, Facundo; Ibarra Eliessetch, José Tomás; Ippi, Silvina; Jauregui, Adrian; Jimenez, Jaime E.; Lammertink, Martjan; Lopez, Fernando; Montellano, Maria Gabriela Nunez; de la Pena, Martin; Rivera, Luis; Vivanco, Constanza; Santillan, Miguel; Soto, Gerardo E.; Vergara, Pablo M.; Wynia, Amy; Politi, Natalia
In the Northern Hemisphere, several avian cavity excavators (e.g., woodpeckers) orient their cavities increasingly toward the equator as latitude increases (i.e. farther north), and it is proposed that they do so to take advantage of incident solar radiation at their nests. If latitude is a key driver of cavity orientations globally, this pattern should extend to the Southern Hemisphere. Here, we test the prediction that cavities are oriented increasingly northward at higher (i.e. colder) latitudes in the Southern Hemisphere and describe the preferred entrance direction(s) of 1,501 cavities excavated by 25 avian species (n = 22 Picidae, 2 Trogonidae, 1 Furnariidae) across 12 terrestrial ecoregions (15 degrees S to 55 degrees S) in South America. We used Bayesian projected normal mixed-effects models for circular data to examine the influence of latitude, and potential confounding factors, on cavity orientation. Also, a probability model-selection procedure was used to simultaneously examine multiple orientation hypotheses in each ecoregion to explore underlying cavity-orientation patterns. Contrary to predictions, and patterns from the Northern Hemisphere, birds did not orient their cavities more toward the equator with increasing latitude, suggesting that latitude may not be an important underlying selective force shaping excavation behavior in South America. Moreover, unimodal cavity-entrance orientations were not frequent among the ecoregions analyzed (only in 4 ecoregions), whereas bimodal (in 5 ecoregions) or uniform (in 3 ecoregions) orientations were also present, although many of these patterns were not very clear. Our results highlight the need to include data from under-studied biotas and regions to improve inferences at macroecological scales. Furthermore, we suggest a re-analysis of Northern Hemisphere cavity orientation patterns using a multi-model approach, and a more comprehensive assessment of the role of environmental factors as drivers of cavity orientation at different spatial scales in both hemispheres.
Molecular and phylogenetic analysis of herpesviruses in endangered free-ranging cervids of Chile: ovine gammaherpesvirus-2-A novel threat to wild and domestic animal health in Chilean Patagonia
(2024) Hidalgo-Hermoso, Ezequiel; Cabello, Javier; Lopez, Rodrigo; Vergara-Wilson, Vicente; Vera, Frank; Valencia, Carola; Sanchez, Carlos; Celis, Sebastian; Silva, Alejandra; Carinanos, Aintzane; Barria, Ismael; Vicencio, Rocio; Munoz-Leal, Sebastian; Aravena, Paula; Lagos, Rocio; Toro-Letelier, Juan; Verasay-Caviedes, Sebastian; Garnham, Antonio; Pena, Irene; Sanchez, Fernando; Moreira-Arce, Dario; Vergara, Pablo M.; Alegria-Moran, Raul; Cortes-Hinojosa, Galaxia
Introduction Herpesvirus infections have been highlighted as emerging diseases affecting wildlife health and the conservation of several taxa. Malignant catarrhal fever (MCF) and infectious keratoconjunctivitis (IKC) are two viruses that infect wild ruminants. Nevertheless, epidemiological data on herpesviruses in South American wild ruminants are limited. An outbreak of caprine gammaherpesvirus-2 (CpHV-2) that recently was suspected as the cause of MCF in southern pudus (Pudu puda) prompted the need to conduct molecular screenings in Chilean cervids to understand the epidemiology of herpesviruses. The aim of this study was to determine the occurrence and genetic diversity of herpesviruses in free-ranging cervids from Chile.Methods Herpesvirus infection was assessed in antemortem blood samples (n = 86) from pudus (n = 81) and huemuls (Hippocamelus bisulcus) (n = 5), as well as postmortem samples of spleen (n = 24) and lung (n = 3) from pudus, using a nested pan-herpesvirus PCR assay.Results Combining all suitable sample types, DNA of pudu gammaherpesvirus-1 was detected in five pudues and five huemuls, with an overall prevalence of 9.90% (n = 10/101; 95% CI = 5.11-17.87%). One pudu tested positive for ovine gammaherpesvirus-2 (n = 1/96; 1.04%; 95% CI = 0.05-6.49%), and one pudu tested positive for a Macavirus sequence with 98.63 similarity to ovine gammaherpesvirus-2 (n = 96; 1.04%; 95% CI = 0.05-6.49%).Discussion To the best of our knowledge, this is the first report of a herpesvirus in huemul and of ovine gammaherpesvirus-2 in Chile. Our results also confirm the active circulation of herpesvirus in free-ranging cervids in Chilean Patagonia, and as such, MCF should be considered as a possible cause of disease in free-ranging Chilean pudus and livestock species. Further research is necessary to develop a plan of systematic monitoring (serological and pathological screening) of herpesviruses in Chilean wild and domestic ruminants to understand their diversity and impact on animal health and conservation.
Multiple environmental drivers for the Patagonian forest-dwelling beetles: Contrasting functional and taxonomic responses across strata and trophic guilds
(2022) Vergara, Pablo M.; Fierro, Andres; Carvajal, Mario A.; Alaniz, Alberto J.; Quiroz, Madelaine
changes in forest-dwelling beetle communities. However, the effects of multiple environmental factors can be complex to detect in ecosystems that offer a broad variety of microhabitats for a great variety of beetle species. This is the case in Patagonian temperate forests, where the use of remote sensing provides an opportunity to evaluate the sensitivity of beetle species to environmental changes. Here, we identified the environmental drivers of forest-dwelling beetle communities in the ground and canopy of 34 north Patagonian-forest landscapes. We analyzed the associations of the taxonomic and functional diversity of five trophic guilds with 30 remote-sensing variables of landscape structure, composition, and disturbances; vegetation and soil properties; and climate and physical variables. Hierarchical clustering analysis was used to identify trophic guilds responding similarly to predictors. Segmented regression analysis was used to evaluate functional redundancy from taxonomic-functional richness relationships. A total of 583 species (23,848 individuals) of beetles were recorded for both strata. The effects of environmental variables were heterogeneous across strata and guilds. Canopy beetles were especially sensitive to early successional conditions, and canopy attributes, but also benefited from the canopy openness. Forest specialists of the ground and canopy responded differently to environmental variables. Ground-dwelling beetles were mostly affected by fires, human modifications, edge closeness, high temperatures, and soil properties, responding weakly to canopy properties. Functional redundancy
Multiscale spatial analysis of headwater vulnerability in South-Central Chile reveals a high threat due to deforestation and climate change
(2022) Alaniz, Alberto J.; Smith-Ramirez, Cecilia; Rendon-Funes, Adriana; Hidalgo-Corrotea, Claudia; Carvajal, Mario A.; Vergara, Pablo M.; Fuentes, Norka
Headwaters represent an essential component of hydrological, ecological, and socioeconomical systems, by providing constant water streams to the complete basin. However, despite the high importance of headwaters, there is a lack of vulnerability assessments worldwide. Identifying headwaters and their vulnerability in a spatially explicit manner can enable restauration and conservation programs. In this study, we assess the vulnerability of headwaters in South -Central Chile (38.4 to 43.2 degrees S) considering multiple degradation factors related to climate change and land cover change. We analyzed 2292 headwaters, characterizing multiple factors at five spatial scales by using remote sensing data related to Land Use and Cover Change (LUCC), human disturbances, vegetation cover, climate change, potential water demand, and physiography. We then generated an index of vulnerability by integrating all the analyzed vari-ables, which allowed us to map the spatial distribution of headwater vulnerability. Finally, to estimate the main drivers of degradation, we performed a Principal Components Analysis with an Agglomerative Hierarchical Clustering, that allowed us to group headwaters according to the analyzed factors. The largest proportion of most vulnerable headwa-ters are located in the north of our study area with 48.1 %, 62.1 %, and 28.1 % of headwaters classified as highly vul-nerable at 0, 10, and 30 m scale, respectively. The largest proportion of headwaters are affected by Climate Change (63.66 %) and LUCC (23.02 %) on average across all scales. However, we identified three clusters, in which the north-ern cluster is mainly affected by LUCC, while the Andean and Coastal clusters are mainly affected by climate change. Our results and methods present an informative picture of the current state of headwater vulnerability, identifying spa-tial patterns and drivers at multiple scales. We believe that the approach developed in this study could be useful for new studies in other zones of the world and can also promote Chilean headwater conservation.
Native bees in Mediterranean semi-arid agroecosystems: Unravelling the effects of biophysical habitat, floral resource, and honeybees
(2021) Rodriguez, Sharon S.; Perez-Giraldo, Laura C.; Vergara, Pablo M.; Carvajal, Mario A.; Alaniz, Alberto J.
The sustainable provision of pollination services in large regions of the Nearctic and Neotropics usually involves the coexistence of a rich assemblage of native bees and introduced bees in the same agroecosystem. This requires identifying biotic and abiotic conditions that improve the quality of semi-natural habitats surrounding agricultural crops aiming to enhance native bee survival. Here we unravel the contribution of habitat conditions, diversity of flowering plants, and honeybee abundance to the taxonomic diversity, flower visitation rates and functional trait distribution of native bees. We have selected three 1.2 km diameter experimental landscapes in a Mediterranean semi-arid agroecosystem of Central Chile, where wild bees, honeybees, and flowering plants were sampled in 83 10 x 10 m plots. The effects of eleven remote-sensing indices characterizing the habitat conditions, and their interactions with honeybee abundance have been analysed. Native bees were taxonomically richer in semi-natural habitats, with higher surface temperatures and near citrus crops. The flower visitation rates of native bees were positively affected by canopy closure and decreased in sites with a higher terrain slope. Highlands had lower honeybee abundance and native bees were more specialized. We found higher flower visitation rates of native bees on large patches with low abundance of honeybees and small patches with high abundance of honeybees. Visitation rate was also higher in sites with high flowering plant richness and with high abundance of honeybees. These findings suggest that native bees and honeybees differ in their habitat use and flowering resources. This partitioning may enhance, coexistence between these pollinator groups. We suggest that management of Mediterranean agroecosystems be focused on increasing forest canopy closure on the remnants of semi-natural habitats, while maintaining the flower diversity near crops and highlands.
Perspectives on the timing of ecosystem collapse in a changing climate
(2024) Alaniz, Alberto J.; Marquet, Pablo A.; Carvajal, Mario A.; Vergara, Pablo M.; Moreira-Arce, Dario; Muzzio, Miguel A.; Keith, David A.
Climate change is one of the most important drivers of ecosystem change, the global-scale impacts of which will intensify over the next 2 decades. Estimating the timing of unprecedented changes is not only challenging but is of great importance for the development of ecosystem conservation guidelines. Time of emergence (ToE) (point at which climate change can be differentiated from a previous climate), a widely applied concept in climatology studies, provides a robust but unexplored approach for assessing the risk of ecosystem collapse, as described by the C criterion of the International Union for Conservation of Nature's Red List of Ecosystems (RLE). We identified 3 main theoretical considerations of ToE for RLE assessment (degree of stability, multifactorial instead of one-dimensional analyses, and hallmarks of ecosystem collapse) and 4 sources of uncertainty when applying ToE methodology (intermodel spread, historical reference period, consensus among variables, and consideration of different scenarios), which aims to avoid misuse and errors while promoting a proper application of the framework by scientists and practitioners. The incorporation of ToE for the RLE assessments adds important information for conservation priority setting that allows prediction of changes within and beyond the time frames proposed by the RLE.
Rapid behavioral recovery based on environmental enrichment of a white-throated toucan (Ramphastos tucanus: Ramphastidae) affected by collision trauma
(2022) Alaniz, Alberto J.; Astudillo-Hinojosa, Karina; Soto, Ana Francisca; Vergara, Pablo M.; Carvajal, Mario A.; Moreira-Arce, Dario
Captive animals that have experienced traumatic events require a high range of care prior to reintro-ducing them into their natural habitat; and this care should ensure their welfare in captivity. This re-port shows the ethological evolution of beneficial effects attributed to environmental enrichment. Specif-ically, the report focuses on the recovery of a white-throated toucan (Ramphastos tucanus: Ramphastidae) affected by a collision trauma resulting in a skull fracture, which received treatment and care in the Taricaya wildlife rescue center (Madre Selva, Peru). An environmental enrichment protocol was imple-mented for 30 days, recording all activities during this period. We performed generalized linear models to identify significant trends in the observed activities. We showed that inactive time and self-mutilation significantly decreased, while walking, eating, and washing activities increased during the study period. Temporal improvement in toucan welfare may be associated with higher energy (walking), better nutri-tion (eating), and decreased stress, as shown by reduced self-mutilation. Our report provides evidence on the favorable outcome of environmental enrichment in a toucan, raising its importance as a management tool for veterinary practitioners in wildlife rescue centers. (c) 2022 Elsevier Inc. All rights reserved.
Remote-sensing estimates of forest structure and dynamics as indicators of habitat quality for Magellanic woodpeckers
(2021) Alaniz, Alberto J.; Carvajal, Mario A.; Fierro, Andres; Vergara-Rodriguez, Valentina; Toledo, Gisela; Ansaldo, Diego; Moreira-Arce, Dario; Rojas-Osorio, Alejandro; Vergara, Pablo M.
Bridging remote-sensing ecosystem indices with biodiversity conservation implies converting these indices into habitat quality indicators for species playing an important role in communities and ecosystems, such as woodpeckers. However, an ecologically reliable estimation of habitat quality necessarily involves an assessment of fitness components ultimately responsible for population persistence. Here, we assessed the relationship between remote-sensing indices of forest structure, dynamics and composition with the breeding performance of Magellanic woodpeckers in conservation areas of southern Chile. We used a Bayesian-spatial model based on age and sex information from woodpecker?s social group data collected seasonally in seven years. The probability of a young remaining in the group decreased with the mean group size during the previous year, with group size fluctuating temporally in all conservation areas. Tree senescence had a positive effect on the pairing probability of woodpeckers, but this effect became more marked in sites of higher altitude. Paired woodpeckers were more likely to be observed in sites supporting more than 69% of forest cover. The probability of the young remaining in the territory was positively affected by the interaction between forest canopy continuity and altitude, with retention of the young being more likely in sites located higher than 1000 masl. Social groups were larger in sites where the continuity of canopy increased over time. Those findings suggest that remote sensing indices representing the structure and dynamics of forest ecosystems are important indicators of the habitat quality for woodpeckers. Thus, forest biodiversity that depends on the woodpecker?s engineering function may be conserved through the retention of senescent trees and the maintaining of critical levels of forest cover ensuring high habitat-quality for breeding woodpeckers.
Scale-dependent habitat use from an individual-based perspective: the case of the endangered Darwin's fox living in heterogeneous forest landscapes
(2021) Moreira-Arce, Dario; Cabello, Javier; Meneses, Luis O.; Norambuena, Katherine; Perez-Hernandez, Christian G.; Hidalgo-Hermoso, Ezequiel; Alaniz, Alberto J.; Vergara, Pablo M.
Context Understanding how rare and threatened species respond to habitat heterogeneity at different spatial scales requires unbiased population-level parameters incorporating individual variability in occurrence and detection probabilities.
Unraveling the socio-environmental drivers during the early COVID-19 pandemic in China
(2023) Alaniz, Alberto J.; Vergara, Pablo M.; Carvajal, Jorge G.; Carvajal, Mario A.
The effect of environmental and socioeconomic conditions on the global pandemic of COVID-19 had been widely studied, yet their influence during the early outbreak remains less explored. Unraveling these relationships represents a key knowledge to prevent potential outbreaks of similar pathogens in the future. This study aims to determine the influence of socioeconomic, infrastructure, air pollution, and weather variables on the relative risk of infection in the initial phase of the COVID-19 pandemic in China. A spatio-temporal Bayesian zero-inflated Poisson model is used to test for the effect of 13 socioeconomic, urban infrastructure, air pollution, and weather variables on the relative risk of COVID-19 disease in 122 cities of China. The results show that socioeconomic and urban infrastructure variables did not have a significant effect on the relative risk of COVID-19. Meanwhile, COVID-19 relative risk was negatively associated with temperature, wind speed, and carbon monoxide, while nitrous dioxide and the human modification index presented a positive effect. Pollution gases presented a marked variability during the study period, showing a decrease of CO. These findings suggest that controlling and monitoring urban emissions of pollutant gases is a key factor for the reduction of risk derived from COVID-19.

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