Using statistics to design and estimate vital rates in matrix population models for a perennial herb. Issue 1 (23rd October 2019)

• Record Type: Journal Article
• Authors: Ramula, Satu; Kerr, Natalie Z.; Crone, Elizabeth E.
• Is Part Of: Population ecology. Volume 62:Issue 1(2020)
• Page Start: 53
• Page End: 63
• Publication Date: 2019-10-23
• Subjects: demography -- matrix population model -- plant population dynamics -- stochasticity -- vital rates; Animal populations -- Periodicals; Insect populations -- Periodicals; 591.788
• DOI: 10.1002/1438-390X.12024
• Languages: English
• ISSNs: 1438-3896

Abstract

Abstract: Matrix population models are widely used to assess population status and to inform management decisions. Despite existing theories for building such models, model construction is often partially based on expert opinion. So far, model structure has received relatively little attention, although it may affect estimates of population dynamics. Here, we assessed the consequences of two published matrix structures (a 4 × 4 matrix based on expert opinion and a 10 × 10 matrix based on statistical modeling) for estimates of vital rates and stochastic population dynamics of the long‐lived herb Astragalus scaphoides . We explored the ways in which choice of model structure alters the accuracy (i.e., mean) and precision (i.e., variance) of predicted population dynamics. We found that model structure had a negligible effect on the accuracy and precision of vital rates and stochastic stage distribution. However, the 10 × 10 matrix produced lower estimates of stochastic population growth rates than the 4 × 4 matrix, and more accurately predicted the observed trends in population abundance for three out of four study populations. Moreover, estimates of realized variation in population growth rate due to fluctuations in population stage structure over time were occasionally sensitive to matrix structure, suggesting differential roles of transient dynamics. Our study indicates that statistical modeling for choosing categories in matrix models might be preferable over expert opinion to accurately predict population trends and can provide a more objective way for model construction when the biological knowledge of the species is limited. Abstract : We assessed the consequences of two published matrix structures (a 4 × 4 matrix based on expert opinion and a 10 × 10 matrix based on statistical modelling) for estimates of vital rates and stochastic population dynamics of the long‐lived herb Astragalus scaphoides . Our findings indicate that while matrix structure may not matter for estimates of some population parameters (e.g., the accuracy and precision of vital rates and stochastic stable stage distribution), it may affect estimates of stochastic population growth rate. Overall, statistical modeling to choose model structure might predict population trends more accurately than a model constructed based on expert opinion.