With this, these variables could be used to create general mathematical models which could be plugged into multiple data sets. given to the Grinnellian over Eltonian niche has important limitations, as knowledge of where species may occur is less useful and reliable in the absence of knowledge about their ecological function (Schmitz et al. GRINNELLIAN VS. ELTONIAN SPECIALIZATION Ecological specialization is often deﬁned as the restricted eco-logical niche breadth (orwidth) of agiven species (Futuyma & Moreno 1988). In the recent past, availability of large data sets of species presences has increased by orders of magnitude. In this article we distinguish between Eltonian niches , which are spatially fine-grained and based on variables related to ecological interactions and resource consumption, and Jackson and Overpeck's meaning , the Grinnellian niches (24, 25). Using only noninteractive, nonconsumable scenopoetic variables as axes in the multidimensional niche space is what characterizes Grinnellian niches… Thrasher" (Grinnell, 1917). The Main point:Soberón’s idea of a niche is focused on segregating large spatial scale abiotic variables and local spatial scale biotic variables into two distinct classes: Grinnellian and Eltonian niches. In other words, the niche is the sum of the habitat requirements and behaviors that allow a species to persist and produce offspring. This, together with developments in geographical information systems and statistical methods, has enabled scientists to calculate, for Niches and distributional areas: Concepts, methods, and assumptions Jorge Sobero´na,1 and Miguel Nakamurab aBiodiversity Institute, University of Kansas, Dyche Hall, 1345 Jayhawk Boulevard, Lawrence, KS 66045; and bCentro de Investigacio´n en Matema´ticas, A. C. … of traits related to species’ Grinnellian niches, i.e. Niche theory relates both spatial scales by considering the resources (Eltonian niche) and conditions (Grinnellian niche) used by species and allow us to assess the contribution of these factors for species co‐occurrence. traits influencing species’ fitness under different environmental conditions, is well-advanced, there is a lack of studies on the functional diversity related to species’ Eltonian niches, i.e. A Grinnellian niche is determined by the habitat in which a species lives and its accompanying behavioral adaptations. An Eltonian niche emphasizes that a species not only grows in and responds to an environment, it may also change the environment and its behavior as it grows. species’ functional roles in ecological processes and their effects on other species, a discrepancy known as the Eltonian Shortfall. 2003, Elith and Leathwick 2009). The Grinnellian niche concept embodies the idea that the niche of a species is determined by the in which it lives and its accompanyinghabitat behavioral adaptations.