The timing and ecological consequences of Pleistocene megafaunal decline in the eastern Andes of Colombia (article)

This is the final version. Available on open access from Cambridge University Press via the DOI in this recordData availability: The data supporting this publication are openly available from the NERC Data repository or can be accessed by contacting the corresponding author(s).Examining the ecological consequences of the late Quaternary megafaunal extinctions within biodiversity hotspots is crucial for our understanding of the potential consequences of contemporary extinctions. We present the first multi-species record of spores of coprophilous fungi (SCF) from Monquentiva and the high-Andean forests of Colombia to reconstruct Late Pleistocene and Holocene megafaunal abundance. Fossilised pollen and charcoal are used to examine the consequences of megafaunal declines on the surrounding vegetation and fire activity. Our SCF record indicates the presence of Pleistocene megafauna at least since 30,290 BP, with two waves of megafaunal decline at ca. 22,900 BP and 10,990 BP. At Monquentiva, megafaunal decline in the Early Holocene resulted in transitional non-analogue vegetation, loss of some herbivore-dispersed plant taxa, an encroachment of palatable and woody flora, and a rise in fire activity. Differences with other published South-American records suggest that ecological consequences of megafaunal declines were habitat-specific. Overall, we show that ecosystems in the eastern Colombian Cordillera were highly sensitive to the decline of megafaunal populations. Under the current biodiversity crisis, management and conservation efforts must account for the effects of local herbivore declines on plant dispersal, on fire activity, and the potential loss of ecosystem services.Natural Environment Research Council (NERC)Arts and Humanities Research Council (AHRC

Quantifying resilience of socio-ecological systems through dynamic Bayesian networks

This is the final version. Available on open access from Frontiers Media via the DOI in this recordQuantifying resilience of socio-ecological systems (SES) can be invaluable to delineate management strategies of natural resources and aid the resolution of socio-environmental conflicts. However, resilience is difficult to quantify and the factors contributing to it are often unknown. We provide a theoretical and conceptual framework to quantify resilience in a long-term context. Our approach uses elements from interdisciplinarity and network perspectives to establish links and causalities between social and ecological variables and resilience attributes. The evaluation and modeling of SES structure and function are established from the analysis of dynamic Bayesian networks (DBN). DBN models allow quantifying resilience through probabilities and offer a platform of interdisciplinary dialogue and an adaptive framework to address questions on ecosystem monitoring and management. The proposed DBN is tested in Monquentiva, a SES located in the high Andes of Colombia. We determined historical socio-ecological resilience from paleoecological evidence (palynological diversity, forest cover, fires, and precipitation) and social-economic factors (governance, social organization, and connectivity) between 1920 and 2019. We find that transformation processes in Monquentiva are mainly related to social change (e.g., social organization) and increased ecological diversity that in turn have fostered SES resilience between 1980 and 2019. The ability to predict the SES response over time and under cumulative, non-linear interactions across a complex ecosystem highlights the utility of DBNs for decision support and environmental management. We conclude with a series of management and policy-relevant applications of the DBN approach for SES resilience assessment.Natural Environment Research Council (NERC

Holocene fires and ecological novelty in the high Colombian Cordillera Oriental

This is the final version. Available from Frontiers Media via the DOI in this record. DATA AVAILABILITY STATEMENT: The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation. Any queries should be directed towards the corresponding author(s).Rapid climate changes and the increasing presence of humans define the Holocene Epoch (11.6 calibrated kiloyears before present – hereafter kyr BP), when biological systems have faced the most recent and abrupt environmental changes. Understanding how biodiversity responds to extrinsic factors requires determining the effects of varying climatic conditions, changes in disturbance regimes, and increasing anthropogenic impacts. Despite being one center for biodiversity, the potential synergies of long-term anthropogenic and climate changes in shaping areas of high Andean biodiversity have yet to be explored fully. Here we present new pollen and charcoal records from the Pantano de Monquentiva (hereafter Monquentiva) on the highlands of the eastern flank of the Colombian Cordillera Oriental (CCO) to document relationships between climate, vegetation, and fire through the Holocene. We found compositional transitions at 8.7, 6.1, and 4.1 kyr BP at Monquentiva resulting from the interaction of climate, fire, and human occupation. Reduced moisture and temperature caused a compositional shift in Páramo vegetation from ca. 8.7 kyr BP. Fire activity was recorded throughout the Holocene and increased slightly during the Mid-Holocene when regional and local fire decoupling suggested human activities as the source of ignition. Mid-Holocene fires had a large effect on the vegetation composition at Monquentiva which recorded a rapid shift at ca. 6.8 kyr BP. Fire activity increased sharply from 4.1 kyr BP, promoting the reorganization of plant communities at 3.8 kyr BP. This shift in fire activity was likely related to more severe ENSO events and subsequently intensified by human activities after 3.8 kyr BP. Although high climatic sensitivity explains most Holocene vegetation changes in the eastern flank of the CCO, our study highlights the relevance of fire activity, uneven distribution of climatic variables, and human intervention to the composition of the vegetation we see today.Natural Environment Research CouncilNatural Environment Research Counci

Evaluation of propofol as an anesthetic in swine tracheal transplant surgery Evaluación del propofol como anestésico para cerdos sometidos a trasplante de tráquea

Because the swine have been used as an ideal animal model for different medical investigations, it has been useful to the advance in vital organs transplant field. The trachea transplant is a surgical procedure which requires special conditions in anesthetic depth and muscular relax, for a long period, and in addition, an excellent intra and post-operatory analgesic. The aim of this study was to use a combination of xylacine and ketamine, as premedication and evaluate propofol as a general anesthetic in trachea transplant donor or recipient pigs. All the methodology was under the approval of the Committee of Ethics for the Experimentation with Animals of the University of Antioquia. Ten donors and 10 recipients female Yorkshire pigs having a body weight of about 30 kg were used. Trachea extraction from a donor and its transplantation to a recipient in the same surgical procedure was performed. The average body weight (PP) was 30 ± 2.92 kg for both the groups, the average value were as follows: time of recumbency (TR) 8.25 ± 2:85 min; latency period (PL) 6.05 ± 1.73 min, (for both groups); surgical time (TQ) for donors and recipients was 80 ± 0.02, and 247 ± 0.02 min, respectively; heartbeat rate (FC) 90.34 ± 8.14 bpm, O2 saturation (SO2) 95.47 ± 1.79 %; exhaled PCO2 31.13 ± 1.89 mmHg; temperature (T) for both groups was 37.51 ± 0.74ºC. The mean arterial pressure average (PAM) for both group was 65.47 ± 5.94 mmHg; the average time of esternal recumbecency (TRE) for donor female pigs was 16.50 ± 4.09 min, and the average time to stand up (TP) for swine recipients was 30.70 + 3.27 min. These results indicate that Propofol can be considered as a safe anesthetic for use in continuous perfusion. Since it has not an analgesic effect it is strongly recommended to combine it with opioids during anesthetic-surgical procedures; it can be also used with neuromuscular preanesthetics or inhaled anesthetics.<br>Los cerdos se han utilizado como modelo animal ideal para diversas investigaciones médicas; han sido útiles para el avance en el trasplante de órganos. El trasplante de tráquea es un procedimiento quirúrgico que requiere condiciones especiales en profundidad anestésica y relajación muscular por un período largo, y además, una analgesia intra y del postoperatoria excelente. Nuestra investigación utiliza una combinación de xylacine y ketamina, como premedicación y evaluar el propofol como anestésico general en cerdos donantes y receptores en quienes el trasplante de la tráquea sería hecho. Toda la metodología contó con la aprobación del Comité de Ética para la Experimentación con los Animales de la Universidad de Antioquia. Utilizamos 10 donantes y 10 cerdos raza Yorkshire hembras con un peso corporal de cerca de 30 kilogramos. Se realizó la extracción de la tráquea de un donante y el trasplante a un receptor en el mismo procedimiento quirúrgico. El peso corporal (PP) fue de 30 ± 2.92 kg para todo el grupo, el tiempo de recumbencia (TR) para ambos grupos fue de 8.25 ± 2.85 min, el período de latencia (PL) para ambos grupos fue de 6.05 ± 1.73 min, el promedio de tiempo quirúrgico (TQ) para los donantes fue de 80 min ± 0.02, el TQ de los receptores fue de 247m ± 0.02. La presión arterial media (PAM) para todo el grupo fue de 65.47 ± 5.94 mmHg, el promedio de frecuencia cardiaca (FC) para ambos grupos fue de 90.34 ± 8.14 ppm, el promedio de saturación de oxigeno (SO2) fue de 95.47 ± el 1.79% y el CO2 espirado fue de 31.13 ± 1.89 mmHg y el promedio de la temperatura (t) para ambos grupos fue de 37.51 ± 0.74ºC. La tiempo de recumbencia esternal (TRE) para las cerdas donantes fue de 16.50 ± 4.09 min y el tiempo para pararse (TP) para los receptores fue de 30.70 ± 3.27 min. El propofol se puede considerar como anestésico seguro para el uso en la perfusión continua durante la anestesia. Puesto que no tiene un efecto analgésico se recomienda combinarlo con opioides durante procedimientos anestésico-quirúrgicos; puede también ser utilizado con preanestésicos, relajantes musculares o anestésicos inhalados