Hurricane-induced demographic changes in a non-human primate population

Abstract

Major disturbance events can have large impacts on the demography and dynamics of animal populations. Hurricanes are one example of an extreme climatic event, predicted to increase in frequency due to climate change, and thus expected to be a considerable threat to population viability. However, little is understood about the underlying demographic mechanisms shaping population response following these extreme disturbances. Here, we analyse 45 years of the most comprehensive free-ranging non-human primate demographic dataset to determine the effects of major hurricanes on the variability and maintenance of long-term population fitness. For this, we use individual-level data to build matrix population models and perform perturbation analyses. Despite reductions in population growth rate mediated through reduced fertility, our study reveals a demographic buffering during hurricane years. As long as survival does not decrease, our study shows that hurricanes do not result in detrimental effects at the population level, demonstrating the unbalanced contribution of survival and fertility to population fitness in long-lived animal populations.

Rhesus macaques compensate for reproductive delay following ecological adversity early in life

“…In this way, variation in individual quality may mask expected trade‐offs (McLean et al, 2019 ). Although major hurricanes are known to have immediate effects on the mean annual fertility of these females, they have no effects on annual survival, a finding that motivated hypotheses about the potential optimization of life histories by means of ensuring survival on a bad year at the cost of reproduction (Morcillo et al, 2020 ). Finally, our analysis showed that experiencing a hurricane early in life slightly increased the chances of having an LRS equal to 0.…”

“…Hurricanes Hugo and Georges were category 3 hurricanes when their centers were closest to the CSFS (~23 and ~8.4 km from CSFS, respectively). These hurricanes exhibited sustained wind speeds of approximately 201 and 185 km h −1 , respectively, with hurricane‐force winds extending over the entire field station (Morcillo et al, 2020 ). Both hurricanes produced severe damage to Cayo Santiago's vegetation, with 60–90% canopy loss following each hurricane (Morcillo et al, 2020 ).…”

“…These hurricanes exhibited sustained wind speeds of approximately 201 and 185 km h −1 , respectively, with hurricane‐force winds extending over the entire field station (Morcillo et al, 2020 ). Both hurricanes produced severe damage to Cayo Santiago's vegetation, with 60–90% canopy loss following each hurricane (Morcillo et al, 2020 ). Although food provisioning, and thus census taking, resumed after 1 (Hugo) and 2 (Georges) days (Morcillo et al, 2020 ), major hurricanes are significant events that also cause changes in behavior involving an increase in the proximity of social networks (Testard et al, 2021 ).…”

“…Both hurricanes produced severe damage to Cayo Santiago's vegetation, with 60–90% canopy loss following each hurricane (Morcillo et al, 2020 ). Although food provisioning, and thus census taking, resumed after 1 (Hugo) and 2 (Georges) days (Morcillo et al, 2020 ), major hurricanes are significant events that also cause changes in behavior involving an increase in the proximity of social networks (Testard et al, 2021 ). Given negative density dependence in reproduction driven by the annual number of adult females alive in the population (Hernández‐Pacheco et al, 2013 ; Hernández‐Pacheco & Steiner, 2017 ), we also considered the experienced female adult density at birth as a second source of early‐life ecological adversity.…”

“…We focus on major hurricanes and density dependence as main sources of ecological adversity on the rhesus macaque population at Cayo Santiago. Cayo Santiago, located in the Caribbean region, is subjected to major hurricane events which suppress mean annual fertility (Morcillo et al, 2020 ) and change the social structure of the population (Testard et al, 2021 ). Moreover, this population is known to be regulated by density through negative density dependence in fertility (Hernández‐Pacheco, Delgado, et al, 2016 ; Hernández‐Pacheco et al, 2013 ).…”