Differential effects of elevated nest temperature and parasitism on the gut microbiota of wild avian hosts

Background Changes in wild animal gut microbiotas may influence host health and fitness. While many studies have shown correlations between gut microbiota structure and external factors, few studies demonstrate causal links between environmental variables and microbiota shifts. Here, we use a fully factorial experiment to test the effects of elevated ambient temperature and natural nest parasitism by nest flies (Protocalliphora sialia) on the gut microbiotas of two species of wild birds, the eastern bluebird (Sialia sialis) and the tree swallow (Tachycineta bicolor). Results We find that bacterial communities from the nestlings of each host species show idiosyncratic responses to both heat and parasitism, with gut microbiotas of eastern bluebirds more disrupted by heat and parasitism than those of tree swallows. Thus, we find that eastern bluebirds are unable to maintain stable associations with their gut bacteria in the face of both elevated temperature and parasitism. In contrast, tree swallow gut microbiotas are not significantly impacted by either heat or nest parasitism. Conclusions Our results suggest that excess heat (e.g., as a result of climate change) may destabilize natural host-parasite-microbiota systems, with the potential to affect host fitness and survival in the Anthropocene.

Differential Effects of Elevated Nest Temperature and Parasitism on the Gut Microbiota of Wild Avian Hosts

Background: Changes in wild animal gut microbiotas may influence host health and fitness. While many studies have shown correlations between gut microbiota structure and external factors, few studies demonstrate causal links between environmental variables and microbiota shifts. Here, we use a fully factorial experiment to test the effects of elevated ambient temperature and natural nest parasitism by nest flies (Protocalliphora sialia) on the microbiotas of two species of wild birds, the eastern bluebird (Sialia sialis) and the tree swallow (Tachycineta bicolor).Results: We find that bacterial communities from the nestlings of each host species show differential response to both heat and parasitism, with gut microbiotas of eastern bluebirds more disrupted by heat and parasitism than those of tree swallows. Thus, we find that eastern bluebirds are unable to maintain stable associations with their gut bacteria in the face of both elevated temperature and parasitism. In contrast, tree swallow gut microbiotas are not significantly impacted by either heat or nest parasitism.Conclusions: Our results suggest that excess heat (e.g., as a result of climate change) may destabilize natural host-parasite-microbiota systems, with the potential to affect host fitness and survival in the anthropocene.

Reproductive success of Eastern Bluebirds (Sialia sialis) varies with the timing and severity of drought

Drought affects avian communities in complex ways. We used our own and citizen science-generated reproductive data acquired through The Cornell Lab of Ornithology’s NestWatch Program, combined with drought and vegetation indices obtained from governmental agencies, to determine drought effects on Eastern Bluebird (Sialia sialisL.) reproduction across their North American breeding range for the years 2006–2013. Our results demonstrate that some aspects of bluebird reproductive success varies with the timing and severity of drought. Clutch size was unaffected by drought occurrence or severity during or within one and two months of clutch initiation, but hatching and fledging rates decreased as drought severity increased. Drought conditions occurring one month prior to the month during which eggs should have hatched, and two months prior to the month nestlings should have fledged also reduced the numbers of fledged offspring. We also demonstrate the value of datasets generated by citizen scientists in combination with climate data for examining biotic responses at large temporal and spatial scales.

Diagnóstico de las afectaciones socio-ambientales por el ruido en el procesamiento de cacao de la corporación CAORO en el sitio Río Negro

Diagnosis of socio-environmental effects due to noise in cocoa processing of the CAORO corporation at Río Negro site Autores: Yuri Patricio Espinoza Aguilar [email protected] Alex Dumany Luna Florin [email protected] Maria Belén Buele Calderón [email protected] Filiación: Universidad Técnica de Machala Km.5 1/2 Via Machala Pasaje 2983362 - 2983365 - 2983363 - 2983364 [email protected] Resumen En el sector Río Negro perteneciente a la parroquia La Victoria del cantón Santa Rosa, la corporación CAORO (Corporación Agroexportadora El Oro) ha venido desarrollando la actividad de la compra de cacao donde se realiza la fermentación y secado del mismo para la comercialización a nivel nacional y posterior exportación, esta actividad presenta impactos sociales y ambientales los cuales se darán a conocer en la presente investigación. Entre los impactos sociales se encontró que los trabajadores están expuestos por un periodo de tiempo extenso al ruido con decibeles que superan los límites permisibles establecidos en el Texto Unificado de Legislación Secundaria Medio Ambiental, lo que a futuro le puede causar un riesgo a la salud como nerviosismo y sordera. En los impactos ambientales se observó que el ruido afecta a las aves terrestres como Furnarius cinnamomeus, Dives warszewiczi, Ara chloroptera, Eastern bluebird, Columba livia, Turdus merula, del sector causando que se perturben en la búsqueda de alimentos por estar siempre alerta a los depredadores, también algunas aves modificaban su comportamiento natural al trinar en este entorno ruidoso. Las vibraciones generadas por la maquinaria utilizada tienen efectos adversos en la salud del trabajador que habita en la corporación, causando espondilitis, calcificación de discos e incluso menor habilidad manual. En la fauna las vibraciones causan daños mecánicos al aparato digestivo y sistemas respiratorios, además desorientación puesto que cada animal tiene una vibración específica de energía que los ayuda a comunicarse entre sí.