Disentangling the Spatio-Environmental Drivers of Human Settlement: An Eigenvector Based Variation Decomposition

Abstract

The relative importance of deterministic and stochastic processes driving patterns of human settlement remains controversial. A main reason for this is that disentangling the drivers of distributions and geographic clustering at different spatial scales is not straightforward and powerful analytical toolboxes able to deal with this type of data are largely deficient. Here we use a multivariate statistical framework originally developed in community ecology, to infer the relative importance of spatial and environmental drivers of human settlement. Using Moran’s eigenvector maps and a dataset of spatial variation in a set of relevant environmental variables we applied a variation partitioning procedure based on redundancy analysis models to assess the relative importance of spatial and environmental processes explaining settlement patterns. We applied this method on an archaeological dataset covering a 15 km2 area in SW Turkey spanning a time period of 8000 years from the Late Neolithic/Early Chalcolithic up to the Byzantine period. Variation partitioning revealed both significant unique and commonly explained effects of environmental and spatial variables. Land cover and water availability were the dominant environmental determinants of human settlement throughout the study period, supporting the theory of the presence of farming communities. Spatial clustering was mainly restricted to small spatial scales. Significant spatial clustering independent of environmental gradients was also detected which can be indicative of expansion into unsuitable areas or an unexpected absence in suitable areas which could be caused by dispersal limitation. Integrating historic settlement patterns as additional predictor variables resulted in more explained variation reflecting temporal autocorrelation in settlement locations.

The Human Footprint in Mexico: Physical Geography and Historical Legacies

“…Although human modification indices do not convey the entire human effect expressed as changes historically accumulated over natural ecosystems, they are useful to infer the spatial pattern and extent of the capacity of humans to transform the earth through land use [ 11 ]. Many studies analyze how diverse ecological regions have different capacity to respond to landscape transformations (e.g., [ 12 , 13 ]), but only a few of them (e.g., [ 14 – 16 ]) analyze how the physical geography (defined, for example, as biomes or ecoregions) affects the spatial patterns of human modification.…”

Inverse responses of species richness and niche specialization to human development

“…Moreover, previous work has found that reduced species richness is associated with increased nitrogen deposition (Payne et al, 2017) -another environmental variable associated with human development (though the effect of nitrogen on species richness is inconsistent; Peñuelas et al, 2013;Pescott & Jitlal, 2020;Sasaki et al, 2010;Seastedt & Vaccaro, 2001). Indeed, where humans settle on a landscape is non-random (Antrop, 2004;Pickett & Cadenasso, 1995;Vandam et al, 2013) and these confounding variables may influence diversity. Additional work is hence needed to disentangle the relative importance of different variables associated with human development.…”

A Generalized Spatial Measure for Resilience of Microbial Systems

“…For example, the spatial effects of social dilemmas have been investigated for several decades ( Nowak and May, 1992 ; Hauert, 2006 ) and the frequency of human cooperation and collaboration or selfishness and exploitation across spatial dimensions impacts the resilience of groups of peoples and their ability to maintain high productivity ( Alvard, 2004 ; Jimenez et al, 2008 ). Furthermore, spatial patterns of human settlements and population densities may be related to community stability in the face of perturbation events such as loss of water, tillable soil, hunting ground, food, energy and other resources, as well as the related incidents of overpopulation and politico-military conflicts ( Tir and Diehl, 1998 ; Vandam et al, 2013 ). In this context, densities of refugee settlements across countries and subsequent patterns of repopulation of cities after wars may reveal human community and ethno-regional group stability properties in the face of significant devastation.…”