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Fine‐scale spatial variation in fitness is comparable to disturbance‐induced fluctuations in a fire‐adapted species
Author(s) -
Coutts Shaun R.,
QuintanaAscencio Pedro F.,
Menges Eric S.,
SalgueroGómez Roberto,
Childs Dylan Z.
Publication year - 2021
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.1002/ecy.3287
Subject(s) - spatial variability , ecology , population , disturbance (geology) , spatial ecology , vital rates , spatial heterogeneity , variation (astronomy) , extinction (optical mineralogy) , environmental science , scale (ratio) , geography , biology , population growth , demography , statistics , mathematics , cartography , paleontology , physics , sociology , astrophysics
The spatial scale at which demographic performance (e.g., net reproductive output) varies can profoundly influence landscape‐level population growth and persistence, and many demographically pertinent processes such as species interactions and resource acquisition vary at fine scales. We compared the magnitude of demographic variation associated with fine‐scale heterogeneity (<10 m), with variation due to larger‐scale (>1 ha) fluctuations associated with fire disturbance. We used a spatially explicit model within an IPM modeling framework to evaluate the demographic importance of fine‐scale variation. We used a measure of expected lifetime fruit production, E F , that is assumed to be proportional to lifetime fitness. Demographic differences and their effects on E F were assessed in a population of the herbaceous perennial Hypericum cumulicola (~2,600 individuals), within a patch of Florida rosemary scrub (400 × 80 m). We compared demographic variation over fine spatial scales to demographic variation between years across 6 yr after a fire. Values of E F changed by orders of magnitude over <10 m. This variation in fitness over fine spatial scales (<10 m) is commensurate to postfire changes in fitness for this fire‐adapted perennial. A life table response experiment indicated that fine‐scale spatial variation in vital rates, especially survival, explains as much change in E F as demographic changes caused by time‐since‐fire, a key driver in this system. Our findings show that environmental changes over a few tens of meters can have ecologically meaningful implications for population growth and extinction.