A Grinnellian Niche Perspective on Species-Area Relationships

Abstract

In this work, Grinnellian niche theory (a body of theory about geographic distributions of species in terms of noninteracting niche variables) is used to demonstrate that species-area relationships emerge with both size of environmental space and size of geographic area. As environmental space increases, more species' fundamental niches are included, thus increasing the number of species capable of living in the corresponding region. This idea is made operational by proposing a size measure for multidimensional environmental space and approximating fundamental niches with minimum volume ellipsoids. This framework allows estimating a presence-absence matrix based on the distribution of fundamental niches in environmental space, from which many biodiversity measures can be calculated, such as beta diversity. I establish that Whittaker's equation for beta diversity is equivalent to MacArthur's formula relating species numbers and niche breadth; this latter equation provides a mechanism for the species-niche space relationship. I illustrate the theoretical results via exploration of niches of the terrestrial mammals of North America (north of Panama). Each world region has a unique structure of its environmental space, and the position of fundamental niches in niche space is different for different clades; therefore, species-area relationships depend on the clades involved and the region of focus, mostly as a function of MacArthur's niche beta diversity. Analyzing speciesarea relationships from the perspective of niche position in environmental space is novel, shifting emphasis from demographic processes to historical, geographic, and climatic factors; moreover, the Grinnellian approach is based on available data and is computationally feasible.

Environmental heterogeneity predicts global species richness patterns better than area

“…The relative importance of environmental heterogeneity and pure area for species richness can also depend on the region of focus (Sobéron, 2019) and the scale of observation (Palmer & White, 1994). Species–area relationships usually show steeper slopes at fine scales than at large scales (Fridley et al., 2005; Rosenzweig, 1995).…”

The Decline and Impending Collapse of the Atlantic Salmon (Salmo salar) Population in the North Atlantic Ocean: A Review of Possible Causes

“…Indeed, the area of the optimum temperature zone of 4-8 °C for S. salar (Reddin and Shearer 1987) may be expanding (Friedland, et al 2011). Like birds (Tingley et al 2009), salmon probably track their Grinnellian niche through time (Soberón 2019). Even with overall warming of the North Atlantic caused by recent climate change (Friedland et al 2014), the area of the NASpG has remained relatively stable (Hátún et al 2009), and available at-sea habitat for marine growth of salmon although fluctuating from year to year remains relatively unchanged (Friedland and Todd 2012;Nielsen et al 2013;Strøm et al 2020).…”

Diversification in and around the Atlas Mountains: Insights into the systematics and biogeography of the genus Thalpomena (Orthoptera: Acrididae: Oedipodinae)

“…The R package ‘ ellipsenm ’ (Cobos, Osorio‐Olvera, et al, 2019; Cobos, Peterson, et al, 2019) was used to calculate the potential suitable areas based on known occurrences of the identified molecular groups. Distribution models were created utilizing an ellipsoid envelope approach, assuming a species ecological niche from a Grinnellian perspective, as a set of environmental conditions that allow a species to maintain populations for long periods of time, without immigration events (Soberón, 2019). Suitability values represent a multivariate normal transformation of Mahalanobis distances, used to represent how far each combination of environmental conditions is from the optimum (ellipsoid centroid).…”