DOI: 10.5061/dryad.gxd2547p6
title: Unravelling processes between phenotypic plasticity and population dynamics in migratory birds

description: Populations can rapidly respond to environmental change via adaptive
 phenotypic plasticity, which can also modify interactions between
 individuals and their environment, affecting population dynamics. Bird
 migration is a highly plastic resource-tracking tactic in seasonal
 environments. However, the link between the population dynamics of
 migratory birds and migration tactic plasticity is not well understood.
 The quality of staging habitats affects individuals’ migration timing and
 energy budgets in the course of migration, and can consequently affect
 individuals’ breeding and overwintering performance, and impact population
 dynamics. Given staging habitats being lost in many parts of the world,
 our goal is to investigate responses of individual migration tactics and
 population dynamics in the face of loss of staging habitat, and to
 identify the key processes connecting them. We started by constructing and
 analysing a general full-annual-cycle individual-based model with a
 stylized migratory population to generate hypotheses on how changes in the
 size of staging habitat might drive changes in individual stopover
 duration and population dynamics. Next, through the interrogation of
 survey data, we tested these hypotheses by analysing population trends and
 stopover duration of migratory waterbirds experiencing loss of staging
 habitat. Our modelling exercise led to us posing the following hypotheses:
 the loss of staging habitat generates plasticity in migration tactics,
 with individuals remaining on the staging habitat for longer to obtain
 food due to a reduction in per capita food availability. The subsequent
 increasing population density on the staging habitat has knock on effects
 on population dynamics in the breeding and overwintering stage. Our
 empirical results were consistent with the modelling predictions. Our
 results demonstrate how environmental change that impacts one
 energetically costly life history stage in migratory birds can have
 population dynamics impacts across the entire annual cycle via phenotypic
 plasticity.
description: IBM: The individual-based model was constructed in
 NetLogo Bird survey data: Bird surveys were conducted
 in the wetlands in the north of Bohai Bay, located in the northwest of the
 Yellow Sea. The survey range is shown in Fig S3. Survey data was collected
 between 2004 and 2018 by using telescopes and binoculars.
description: <strong>1. NetLogo code for the individual-based
 model</strong> NetLogo code to construct the
 individual-based model with capital breeding tactic and income breeding
 tactic respectively, and to get the model outputs including: total number
 of individuals, daily population density at each habitat, individual time
 spent at each habitat, individual energy reserves when leaving each
 habitat and individual energy reserves at each time step. Different
 habitat scenarios and sensitivity analysis can be run by using the
 "behaviour space". The model scenarios, the
 decision rules, the order of events of the model are fully described in
 the paper.  Code_IBM_CapitalBreeding.nlogo
 Code_IBM_IncomeBreeding.nlogo <strong>2.
 Bird survey data</strong> The dataset comes from
 the long-term bird survey project on the Bohai Bay, China, run by Beijing
 Normal University (BNU). The data provided here is a subset of the full
 dataset, which includes bird surveys from 2016 to 2018. If you are
 interested in the full dataset, please contact Zhengwang Zhang
 (BNU). Key to variables: year: is
 the year of the survey month: is the month of the
 survey day: is the date of the survey
 julian: is the Julian date of the survey area:
 is the survey site, the location of the survey site can be found in
 Fig.S3 species: is the common English name of the
 species. The "uncurlew sp.", "unduck sp.",
 "untern sp." are species that cannot be identified as species
 level, they were all treated as unidentified species in our
 analyses. number: is the population size of the species
 at the survey site at the specific survey date effort:
 is the number of observers of the survey
 Survey_data_BNU.csv
 figure_S3_SurveyArea.tif