Spatial Ecosystem Models – a Brief Overview
Most ecosystem models lie on a continuum of basic to applied objectives with related modelling trade offs (DeAngelis and Yurek 2016). Basic ecosystem models are often mathematical models, primarily intended to develop, test, and formalize ecosystem theory (Jørgensen 2016). Most of these models have been aspatial, spatially implicit, or limited to few geographic sites and ecosystems (DeAngelis and Yurek 2016). The other end of the spectrum is marked by applied ecosystem models, which are usually fit to empirical data (Evans 2012) or derived using expert-based protocols (Halvorsen et al 2020). Applied models are normally intended for description or prediction of ecosystem conditions, including their specific arrangement in geographic space (Pickett and Candenasso 2002, Evans 2012, Geary et al 2020). Recently though, increasing awareness of the importance of space in shaping ecosystem pattern and process has prompted appeals to extend spatially explicit ecosystem modelling more evenly across scientific domains (e.g., DeAngelis and Yurek 2016, Fulton et al 2019). Spatially explicit approaches are not necessary in all ecosystem models, but they are indispensable for models intended for making predictions of ecosystems across landscapes (Evans 2012). We highlight the importance of spatially explicit modelling approaches as a strategy to help bridge theoretical and applied branches of ecosystem science. Furthermore, we demonstrate their use for contemporary and near-future ecosystem predictions, at local to regional landscape extents.
Ecosystems occur in geographic space (Pickett and Candenasso 2002) and space has long been recognized as a fundamental property mediating the expression of ecosystem heterogeneity (Rowe 1961, Holling 1992). Yet until recently, advances in spatially explicit ecosystem modelling have occurred under the somewhat independent auspices of ecosystem and landscape ecology (Loreau et al 2003). The latter discipline has commonly considered ecosystems and ecosystem processes as landscape components, focusing on their contributions to spatial heterogeneity (Pickett and Cadenasso 1995). Ecosystem ecologists have, in turn, mainly concentrated their attention on the exchange of organisms, energy, materials – particularly resources such as inorganic nutrients – along continuous geographic gradients or discretized landscape mosaics (Massol et al 2011, Gounand et al 2018). Their burgeoning approach – sometimes called ‘spatial or landscape ecosystem ecology ’ (sensu Loreau et al 2003) – often uses the meta-ecosystem as an analytical construct (Massol et al 2011) and frequently relies on mathematical models (e.g., Harvey et al 2021). However, current perspectives in spatial ecosystem ecology (e.g., Leroux et al 2017, Gounand et al 2018, Harvey et al 2021) call for improved integration of ecosystem and meta-ecosystem models with real-world landscape contexts to inform conservation policy. Thus far, this synthesis of landscape and ecosystem ecology has predominantly been championed through spatially explicit models of ecosystem functional properties (e.g., Leroux and Loreau 2012, Gounand et al 2018, Soranno et al 2019). We contend further synthesis is needed to predict other spatially structured aspects of ecosystem variation, including common pools of biotic and abiotic complexity at local and regional landscape extents. Furthermore, those biotic and abiotic factors interacting in a particular time and place, influence location-specific patterns of ecosystem compositional, structural, and functional properties (Nash et al 2014). The spatially explicit ecosystem modelling strategy presented in this forum is structured to illustrate these interdependent aspects of intra- and inter-ecosystem organization and variation.