A critical comparison of integral projection and matrix projection models for demographic analysis

Doak, Daniel F.; Waddle, Ellen; Langendorf, Ryan E.; Louthan, Allison M.; Chardon, Nathalie Isabelle; Dibner, Reilly R.; Keinath, Douglas A.; Lombardi, Elizabeth; Steenbock, Christopher M.; Shriver, Robert K.; Linares, Cristina; Garcia, María Begoña; Funk, W. Chris; Fitzpatrick, Sarah W.; Morris, William F.; DeMarche, Megan L.

doi:10.1002/ecm.1447

Cited by 25 publications

(27 citation statements)

References 105 publications

(198 reference statements)

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“…Our selection of environmental variables used for all species imply that models constructed here for the purpose of a comparative study on demographic compensation will be different from those that might be constructed for other purposes or in studies focusing on single species. Although IPMs are increasingly used in demographic studies, their predictions have only rarely been verified (Doak et al, 2021; Ramula et al, 2009). More model validation efforts from other perspectives, for instance using (independent) presence/absence data of simulated species across environmental ranges (Schultz et al, 2022), may allow evaluating whether and when demographic models capture population performance.…”

Section: Discussionmentioning

confidence: 99%

The role of demographic compensation in stabilising marginal tree populations in North America

et al. 2022

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Demographic compensation-the opposing responses of vital rates along environmental gradients-potentially delays anticipated species' range contraction under climate change, but no consensus exists on its actual contribution. We calculated population growth rate (λ) and demographic compensation across the distributional ranges of 81 North American tree species and examined their responses to simulated warming and tree competition. We found that 43% of species showed stable population size at both northern and southern edges. Demographic compensation was detected in 25 species, yet 15 of them still showed a potential retraction from southern edges, indicating that compensation alone cannot maintain range stability. Simulated climatic warming caused larger decreases in λ for most species and weakened the effectiveness of demographic compensation in stabilising ranges. These findings suggest that climate stress may surpass the limited capacity of demographic compensation and pose a threat to the viability of North American tree populations.

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Section: Discussionmentioning

confidence: 99%

The role of demographic compensation in stabilising marginal tree populations in North America

et al. 2022

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“…We constructed size‐based demographic models using continuous size‐based vital rate functions, which can be viewed either as projection matrices or integral projection models (Caswell, 2001; Doak et al, 2021; Morris & Doak, 2002). Using tree height as our size‐classifying variable (hereafter “height classes”), we created mixed linear and general linear models for growth, variance in growth, survival, probability of reproduction, and number of seeds produced given reproduction.…”

Section: Methodsmentioning

confidence: 99%

Demographic consequences of mutualism disruption: Browsing and big‐headed ant invasion drive acacia population declines

Hays

Riginos

Palmer

et al. 2022

Ecology

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Across the globe, biological invasions have disrupted mutualisms, producing reverberating consequences for ecosystems. Although invasive species frequently trigger mutualism disruptions, few studies have quantified the demographic mechanisms by which mutualism breakdown may generate population effects. In a Kenyan savanna, the invasive big-headed ant (Pheidole megacephala) has disrupted a foundational mutualism between the monodominant whistling-thorn tree (Acacia drepanolobium) and native ants (Crematogaster spp.) that deter browsing by large mammalian herbivores. We conducted experiments to quantify the demographic consequences of this mutualism disruption in the presence and absence of large mammalian herbivores. Invasion by P. megacephala exacerbated population declines of A. drepanolobium, primarily through decreased survival and reproduction of adult trees. However, these fitness reductions were small compared to those resulting from the presence of large mammalian herbivores, which negatively impacted growth and survival. Contrary to expectation, the expulsion of metabolically costly Crematogaster mutualists by P. megacephala did not result in higher population growth rates for trees protected from large mammalian herbivores. Our results suggest that invasive P. megacephala may impose a direct metabolic cost to trees exceeding that of native mutualists while providing no protection from browsing by large mammalian herbivores. Across landscapes, we expect that invasion by P. megacephala will reduce A. drepanolobium populations, but that the magnitude and demographic pathways of this effect will hinge on the presence and abundance of browsers.

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“…The advent of the more versatile IPMs does not mean that MPMs must be abandoned. Doak et al (2021) compared key outputs from both approaches (population growth rate, sensitivity and elasticity patterns, life expectancy and damping ratio; some of these parameters are defined later) and found no large differences between models, especially when MPMs were built using ten or more categories. Arguments in favour of MPMs are ease of construction and interpretation.…”

Section: O N L I N E F I R S Tmentioning

confidence: 99%

“…In this paper we specifically concentrate on structured population models, which incorporate the change in individual demographic processes (fecundity, ontogenetic development -often referred to simply as growth-and survival, also called vital rates) in the course of the life cycle. Over the last half century, population ecologists have employed these models to record the dynamics of a wide variety of wild, threatened, invasive or economically important species (Crone et al 2011, Doak et al 2021. The growth in the number of studies is witnessed by the COMPADRE database which currently contains 8,708 matrix population models of 757 plant species from 639 publications (COMPADRE 2021).…”

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confidence: 99%

Conceptual and methodological issues in structured population models of plants

Martinez

Martorell²,

Franco

2022

Bot. Sci.

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Structured projection models (SPMs) are a powerful tool to investigate the dynamics of structured populations, which makes them ideal for the study of plant species spanning their range of life forms, sizes, longevity, and life cycle complexity. They are one of the most versatile tools in plant ecology, with hundreds of species studied so far and a wide variety of alternative formulations for different questions and purposes. We revise some of the most salient conceptual and methodological issues in the construction and use of SPMs including both discrete matrix projection models and continuous integral projection models. Consideration is given to the selection of the state variable and the estimation of parameters, especially those involving transitions difficult to observe in the field, such as the quantification of offspring production and the rarely observed mortality of individuals towards the end of the life cycle. Due to the growing importance of investigating population trends in a rapidly changing world, we highlight the use of SPMs for populations under a variety of environmental influences and/or away from their expected equilibrium. The presumed role of population density receives special attention because it often correlates with features of the environment, thus potentially confounding the two effects. Similarly, disentangling the various environmental effects poses challenges of its own, making it difficult to prove causality. The alternatives available are illustrated considering the selection of variables, samples, and model type suitable for specific purposes.

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A critical comparison of integral projection and matrix projection models for demographic analysis

Abstract: 2021. A critical comparison of integral projection and matrix projection models for demographic analysis. Ecological Monographs 91(2):e01447.

Cited by 25 publications

References 105 publications

The role of demographic compensation in stabilising marginal tree populations in North America

The role of demographic compensation in stabilising marginal tree populations in North America

Demographic consequences of mutualism disruption: Browsing and big‐headed ant invasion drive acacia population declines

Conceptual and methodological issues in structured population models of plants

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