Which temporal resolution to consider when investigating the impact of climatic data on population dynamics? The case of the lesser horseshoe bat (Rhinolophus hipposideros)

Abstract

Climatic variables are often considered when studying environmental impacts on population dynamics of terrestrial species. However, the temporal resolution considered varies depending on studies, even among studies of the same taxa. Most studies interested in climatic impacts on populations tend to average climatic data across timeframes covering life cycle periods of the organism in question or longer, even though most climatic databases provide at least a monthly resolution. We explored the impact of climatic variables on lesser horseshoe bat (Rhinolophus hipposideros) demography based on count data collected at 94 maternity colonies from 2000 to 2014 in Britanny, France. Meteorological data were considered using different time resolutions (month, life cycle period and year) to investigate their adequacy. Model averaging was used to detect significant predictors for each temporal resolution. Our results show that the finest temporal resolution, e.g. month, was more informative than coarser ones. Precipitation predictors were particularly decisive, with a negative impact on colony sizes when rainfall occurred in October, and a positive impact for June precipitations. Fecundity was influenced by April weather. This highlights the strong impact of climatic conditions during crucial but short time periods on the population dynamics of bats. We demonstrate the importance of choosing an appropriate time resolution and suggest that analogous studies should consider fine-scale temporal resolution (e.g. month) to better grasp the relationship between population dynamics and climatic conditions.

Spring weather conditions influence breeding phenology and reproductive success in sympatric bat populations

“…See also Jan et al. () regarding the temporal resolution of climatic variables, which identified April as a critical period influencing bat fecundity based on colony emergence counts. ASFC is largely determined by temperature, with rain and wind having comparatively little effect (see Table S7).…”

The importance of local settings: within-year variability in seawater temperature at South Bay, Western Antarctic Peninsula

“…Although a number of moorings have been deployed along channels and open waters in the WAP (See http://www.soos.aq/activities/soos-at-sea/moorings ), there remains a lack of long-term, high-resolution temperature data from shallow waters in coastal zones dominated by diverse communities of sessile organisms with limited behavioral thermoregulatory ability ( Ashton et al, 2017 ). Fine-scale temporal (daily) data can be crucial for inferring climatic impacts on survival, growth and reproduction ( Kearney, Matzelle & Helmuth, 2012 ), while monthly data is better suited to studying relationships between population dynamics and climatic conditions ( Gutt et al, 2017 ; Jan et al, 2017 ; Kennicutt et al, 2016 ). Observational gaps in surface seawater temperature leave fractionated information that does not provide a coherent and robust picture of the current and future conditions occurring in Antarctic ecosystems.…”

Population-level sensitivity to landscape variables reflects individual-based habitat selection in a woodland bat species

“…From 2000 to 2014, 94 R. hipposideros maternity colonies were monitored in Brittany, France ( Fig. 1, see details in Jan et al, 2017). The following demographic variables were compiled for each colony: mean colony size (the number of adults averaged over the years), fecundity (the juveniles/adults ratio averaged over the years), and growth rate.…”

“…We are very grateful to all volunteers from Bretagne Vivante and Le Groupe Mammalogique Breton for providing visual count data of maternity colonies in Brittany that allowed us to perform this study as well as the companion study published in Oecologia (Jan et al 2017). We thank Benoît Persyn and Météo-France for providing us with meteorological data through the research convention Météo-France/INRA.…”