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.