DOI: 10.5061/dryad.gqnk98svr
title: Guanaco distribution modeling in the last 2500 years in Northwest Patagonia

description: Context: The guanaco is one of the four species of South American camels,
 and is the largest native mammal inhabiting arid and semi-arid
 environments in South America. Although guanaco was abundant and widely
 distributed in the past, currently its density and distribution range are
 substantially reduced, inhabiting mainly in Argentine Patagonia in small
 isolated groups. The decline in guanaco populations is most likely related
 to the Anthropocene defaunation process that is affecting large mammals in
 developing countries worldwide, but the extent and causes of these changes
 are not well understood. Aims: Explore both the changes in the
 distribution of guanaco populations in Northwest Patagonia and the
 environmental and anthropic factors that shaped the distribution patterns,
 employing a long-term perspective spanning from the end of the Late
 Holocene to present times (i.e., last 2500 years). Methods: We
 combine archaeological information, ethnohistorical records and current
 observations and apply Species Distribution Models using bioclimatic and
 anthropic factors as explanatory variables. Key results: Guanaco
 spatial distribution in Northwest Patagonia changed significantly
 throughout time. This change consisted in the displacement of the species
 towards the east of the region and its disappearance from northwest
 Neuquén and southwest Mendoza in the last 30 years. In particular, the
 high-density urban settlements and roads, and secondly, competition with
 ovicaprine livestock (goats and sheep) for forage are the main factors
 explaining the change in guanaco distribution.
 Conclusions: Guanaco and human populations co-existed in the same
 areas during the Late Holocene and historic times, but during the 20th
 century the modern anthropic impact generated a spatial dissociation
 between both species, pushing guanaco populations to drier and
 unproductive areas that were previously peripheral in its distribution.
 Implications:  As with many other large mammal species in
 developing countries, Northwest Patagonia guanaco populations are
 undergoing significant changes in their range due to modern anthropic
 activities. Considering that these events are directly related to
 population declines and extirpations, together with the striking low
 density recorded for Northwest Patagonia guanaco populations, urgent
 management actions are needed to mitigate current human impacts.
description: We collected guanaco occurrences from archaeological,
 ethnohistorical and current sighting data, and separate this data in
 periods (Lata Holocene, Historic and Current). Likewise, different
 bioclimatic and anthropic variables that could contribute to explain
 guanaco distribution in Northwest Patagonia were collected. Finally, the R
 script to model guanaco distribution in each period and estimate the
 explicatory power of each variable is also upload.
description: # Guanaco Distribution Modeling in the last 2500 years in Northwest
 Patagonia
 [https://doi.org/10.5061/dryad.gqnk98svr](https://doi.org/10.5061/dryad.gqnk98svr) Here are guanaco (*Lama guanicoe*) occurrences that we collected from archaeological, ethnohistorical and current sighting data from Northwest Patagonia (Argentina), separated in periods (Lata Holocene, Historic and Current). Likewise, we also provide different bioclimatic and anthropic variables that could contribute to explain guanaco distribution in Northwest Patagonia, as well as the R script to model guanaco distribution in each period and estimate the explicatory power of each variable. We found significant changes in guanaco distribution throughout time. Specifically, in the Current period (last 30 years of sightings) guanaco distribution shifted to the East, and the main explanatory variables are Human footprint and herders summer camps. ## Description of the data and file structure The files upload are: * 3 csv files which contain the guanaco occurrences for the three periods considered, Late Holocene, Historic and Current; * 14 tiff files that are the variables used to model and explain guanaco distribution (8 bioclimatic variables and 6 anthropic variables; see below), all variables were clipped to the study area and standardized; * An R script file that specifies how to develop the step-by-step analyzes that we carried out in the work "Changes in guanaco distribution from Late Holocene to present times in Northwest Patagonia: connecting archaeological, ethnohistoric and current data". These are the bioclimatic and anthropic variables (14 tiff files) that were used to model distribution and are provided in this data set: Bio_1=Annual Mean Temperature (bioclimatic variable downloaded from WorldClim2 at [www.worldclim.org](http://www.worldclim.org); Fick and Hijmans 2017) Bio_2=Mean Diurnal Range (bioclimatic variable downloaded from WorldClim2 at [www.worldclim.org](http://www.worldclim.org); Fick and Hijmans 2017) Bio_3=Isothermality (bioclimatic variable downloaded from WorldClim2 at [www.worldclim.org](http://www.worldclim.org); Fick and Hijmans 2017) Bio_9=Mean Temperature of Driest Quarter (bioclimatic variable downloaded from WorldClim2 at [www.worldclim.org](http://www.worldclim.org); Fick and Hijmans 2017) Bio_12=Annual Precipitation (bioclimatic variable downloaded from WorldClim2 at [www.worldclim.org](http://www.worldclim.org); Fick and Hijmans 2017) Bio_14=Precipitation of Driest Month (bioclimatic variable downloaded from WorldClim2 at [www.worldclim.org](http://www.worldclim.org); Fick and Hijmans 2017) Bio_15=Precipitation Seasonality (bioclimatic variable downloaded from WorldClim2 at [www.worldclim.org](http://www.worldclim.org); Fick and Hijmans 2017) Bio_18=Precipitation of Warmest Quarter (bioclimatic variable downloaded from WorldClim2 at [www.worldclim.org](http://www.worldclim.org); Fick and Hijmans 2017) Human_Density Late Holocene = anthropic variable estimated by us with Kernel density method using archaeological site location data from this period Human_Density Historic = anthropic variable estimated by us with Kernel density method using archaeological site location data from this period Human_Occupation LH  = anthropic variable estimated by us with ESDM methods using archaeological site location data from Late Holocene Human_Occupation Historic = anthropic variable estimated by us with ESDM methods using archaeological site location data from this period Veranada = Summer camps distribution; anthropic variable estimated by us measuring the areas of seasonal occupation of current transhumant herders Hii= Human Footprint; anthropic variable downloaded from Sanderson et al. 2022 at [https://wcshumanfootprint.org/](https://wcshumanfootprint.org/) which summarizes various human activities that currently affect the landscape ## Sharing/Access information The data were taken from many and different type of sources. For more information please search the work "Changes in guanaco distribution from Late Holocene to present times in Northwest Patagonia: connecting archaeological, ethnohistoric and current data", and in its supplementary materials. ## Code/Software The uploaded R script shows the code and the step by step to perform the guanaco distribution analysis. To be able to do them you need to have the QGIS and R software