Oecologia

, Volume 182, Issue 2, pp 475–485

Spatial and temporal synchrony in reptile population dynamics in variable environments

  • Aaron C. Greenville
  • Glenda M. Wardle
  • Vuong Nguyen
  • Chris R. Dickman
Population ecology – original research

DOI: 10.1007/s00442-016-3672-8

Cite this article as:
Greenville, A.C., Wardle, G.M., Nguyen, V. et al. Oecologia (2016) 182: 475. doi:10.1007/s00442-016-3672-8

Abstract

Resources are seldom distributed equally across space, but many species exhibit spatially synchronous population dynamics. Such synchrony suggests the operation of large-scale external drivers, such as rainfall or wildfire, or the influence of oasis sites that provide water, shelter, or other resources. However, testing the generality of these factors is not easy, especially in variable environments. Using a long-term dataset (13–22 years) from a large (8000 km2) study region in arid Central Australia, we tested firstly for regional synchrony in annual rainfall and the dynamics of six reptile species across nine widely separated sites. For species that showed synchronous spatial dynamics, we then used multivariate follow a multivariate auto-regressive state–space (MARSS) models to predict that regional rainfall would be positively associated with their populations. For asynchronous species, we used MARSS models to explore four other possible population structures: (1) populations were asynchronous, (2) differed between oasis and non-oasis sites, (3) differed between burnt and unburnt sites, or (4) differed between three sub-regions with different rainfall gradients. Only one species showed evidence of spatial population synchrony and our results provide little evidence that rainfall synchronizes reptile populations. The oasis or the wildfire hypotheses were the best-fitting models for the other five species. Thus, our six study species appear generally to be structured in space into one or two populations across the study region. Our findings suggest that for arid-dwelling reptile populations, spatial and temporal dynamics are structured by abiotic events, but individual responses to covariates at smaller spatial scales are complex and poorly understood.

Keywords

Population dynamics Simpson Desert Population structure Moran’s theorem Wildfire 

Supplementary material

442_2016_3672_MOESM1_ESM.docx (69 kb)
Supplementary material 1 (DOCX 68 kb)
442_2016_3672_MOESM2_ESM.txt (3 kb)
Supplementary material 2 (TXT 4 kb)

Copyright information

© Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  • Aaron C. Greenville
    • 1
    • 2
  • Glenda M. Wardle
    • 1
    • 2
  • Vuong Nguyen
    • 1
    • 2
  • Chris R. Dickman
    • 1
    • 2
  1. 1.Desert Ecology Research Group, School of Life and Environmental SciencesUniversity of SydneySydneyAustralia
  2. 2.Long Term Ecological Research NetworkTerrestrial Ecosystem Research NetworkSydneyAustralia

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