DOI: 10.5061/dryad.hhmgqnkkc
title: Demographic consequences of changes in environmental periodicity

description: The fate of natural populations is mediated by complex interactions among
 vital rates, which can vary within and among years. While the effects of
 random, among-year variation in vital rates have been studied extensively,
 relatively little is known about how periodic, non-random variation in
 vital rates affects populations. This knowledge gap is potentially
 alarming as global environmental change is projected to alter common
 periodic variations, such as seasonality. We investigated the effects of
 changes in vital-rate periodicity on populations of three species
 representing different forms of adaptation to periodic environments: the
 yellow-bellied marmot (Marmota flaviventer), adapted to strong seasonality
 in snowfall; the meerkat (Suricata suricatta), adapted to inter-annual
 stochasticity as well as seasonal patterns in rainfall; and the dewy pine
 (Drosophyllum lusitanicum), adapted to fire regimes and periodic post-fire
 habitat succession. To assess how changes in periodicity affect population
 growth, we parameterized periodic matrix population models and projected
 population dynamics under different scenarios of perturbations in the
 strength of vital-rate periodicity. We assessed the effects of such
 perturbations on various metrics describing population dynamics, including
 the stochastic growth rate, log λS. Overall, perturbing the strength of
 periodicity had strong effects on population dynamics in all three study
 species. For the marmots, log λS decreased with increased seasonal
 differences in adult survival. For the meerkats, density dependence
 buffered the effects of perturbations of periodicity on log λS. Finally,
 dewy pines were negatively affected by changes in natural post-fire
 succession under stochastic or periodic fire regimes with fires occurring
 every 30 years, but were buffered by density dependence from such changes
 under presumed more frequent fires or large-scale disturbances. We show
 that changes in the strength of vital-rate periodicity can have diverse
 but strong effects on population dynamics across different life histories.
 Populations buffered from inter-annual vital-rate variation can be
 affected substantially by changes in environmentally-driven vital-rate
 periodic patterns; however, the effects of such changes can be masked in
 analyses focusing on inter-annual variation. As most ecosystems are
 affected by periodic variations in the environment such as seasonality,
 assessing their contributions to population viability for future
 global-change research is crucial.
description: <strong>Data
 collection</strong> <strong>Yellow-bellied marmot (<em>Marmota
 flaviventer</em>)</strong><strong> </strong> We used seasonal data on survival,
 life-history stages, and recruitment of individual female yellow-bellied
 marmots. The data were collected between 1976 and 2016 in nine marmot
 colonies living at 2900 masl in the upper East River Valley near Gothic,
 Colorado, United States. To collect these demographic data, individuals
 were live-trapped each year throughout their summer active season, and
 ear-marked in the first capture event. <strong>Meerkat (<em>Suricata
 suricatta</em>)</strong> We used seasonal data on survival,
 life-history stages and social status, emigration, and recruitment of
 individual female meerkats. The data were collected by frequently visiting
 (one to three times per week) wild groups of individually-marked meerkats
 in the Kuruman River Reserve, South Africa. For this study, we used 20
 years of individual data (1997–2016). We also used data on population
 density, calculated as the number of individuals per
 km<sup>2</sup> of population range at each
 census. <strong>Dewy pine (<em>Drosophyllum
 lusitanicum</em>)</strong><strong> </strong> We used data on survival, life-history
 stages, and reproduction of individual dewy pines. The data were collected
 annually for nine years between April 2011 and April 2019 on dewy-pine
 populations occurring in three sites of southern Spain and facing
 different types of post-fire disturbance: human-disturbed (i.e., heavy
 persistent browsing) or natural (i.e., little browsing). The seed
 bank-related vital rates (seed germination or stasis) were estimated from
 seed-burial and greenhouse germination experiments. In addition, we used
 data on population density, calculated as the number of aboveground dewy
 pines per 1-m<sup>2 </sup>square within a study transect in
 each site and each post-fire habitat state.
description: The dataset contains all data
 (as .csv files) to replicate the analyses performed in Conquet et al. 2022
 "<em>Demographic consequences of changing environmental
 periodicity</em>", Ecology. Information regarding specific
 files is available in the README files.