Understanding topography-fog-vegetation relationships in central southern Arabia

Excited to share this new research in the fantastic Remote Sensing in Ecology and Conservation journal.

The cloud forests in Dhofar may be the driest on earth. They receive just 200 mm of rain each year, but during the monsoon/khareef, as much moisture is intercepted from the fog by the forest canopy! This is critical to ecosystem functions and services. Therefore, we hypothesized that vegetation patterns might correlate with fog distributions, which themselves might be affected by the complex mountain topography.

To investigate this, we first needed to map fog distributions at a high resolution (to see the effects of the complex topography). We found that many Landsat scenes showed the fog events, with little interference from other cloud types. So, using Google Earth Engine we extracted fog cover from 257 scenes, and calculated mean (average fog distributions) and SD (fog variability). We used recursive partitioning to analyse how topographic variables influence fog distributions and how fog distributions influence vegetation patterns (NDVI).

We found that fog accumulates against steep windward slopes and landforms, resulting in hotspots of fog interception, while lower fog densities occur in leeward locations. We also found a strong positive correlation between fog density and vegetation greenness. We found hotspots of fog interception, with consistently high fog densities and cloud forest over rough terrain. Complex forest canopy structures intercept more fog moisture than a smooth canopy. We found fog distributions describe patterns of vegetation greenness more accurately than topographic variables alone, and thus, we propose that regional vegetation patterns more closely follow a fog gradient, than an altitudinal gradient as previously supposed.

The Dhofar mountains are home to endemic and threatened biodiversity, and a wealth of archaeological and geological heritage. We hope that our layer of fog density, which is hosted in the PANGAEA data repository (doi.org/10.1594/PANGAE), will enable an improved understanding of how species and in Dhofar respond to local variability in topoclimatic conditions.

Growing Pastoral Societies

Daniel Peart presented preliminary results from our model of social-spatial patterns in pastoralism at the annual meetings of the American Anthropological Association in Vancouver, Canada. 

Daniel Peart presenting at the AAA meetings.

Simulating pastoralism in Dhofar

Work is underway to design an Agent-based model of contemporary pastoralism in Dhofar, which will then form the basis of the ancient model to test theories on pastoralist mobility, habitation and monument building in ancient Dhofar. In these photos, the team is busy creating conceptual diagrams of attributes and properties of the different agents in the model, and how they relate to one another.

Building in high resolution elevation attributes

Lawrence Ball generated geospatial data sets that generate layers of fog, elevation and other attributes of the Dhofar mountains. Daniel Peart is building these into a realistic agent-based model for the Dhofar human-ecosystem. The first display of elevation data in Netlogo is impressive!

A new narrative for teaching archaeology!

Joy McCorriston and co-author Julie Field published a new introductory textbook with a new narrative of the evolutionary context of our human historical ecology. The narrative introduces diversity in prehistory, establishes technology as the interface of humans and environments, showcases peopling the world, digging in, extinctions in the past, human behavioral ecology, producing food, humans as agents, feeding cities, building monuments-building society, conspicuous consumption, writing, extractivism, and choice in the Anthropocene future. Survey and excavations that led up to the ASOM Project are in the book.

Dr. Buffington accepts a new postdoctoral appointment!

Abigail Buffington PhD in her new surroundings at College of William and Mary, where she has accepted a position on a National Science Foundation funded project to examine land use histories in Pacific Islands using agent-based modelling (Jennifer Kahn, PI). ASOM wishes her all success and will continue to publish together and collaborate as her career develops.

Kyle Riordan rejoins ASOM team

Welcome back, Kyle Riordan! After completing an MA in Anthropology, Kyle rejoins the team to continue sediment analyses and help out with coordinating termite mound paleoproxy studies and communications among a team spread across Ohio, Pennsylvania, Virginia, Nice France and Moscow Russia.

Papers presented at the Seminar for Arabian Studies

PI Joy McCorriston and Abigail Buffington presented two papers on ASOM research at the Seminar for Arabian Studies, this year in Leiden (the Netherlands). McCorriston presented a paper on monuments in Dhufar with an emphasis on boat-shaped graves the team excavated at D114 this past field season. Buffington presented the results of the settlement survey along with preliminary spatial analysis. Additionally, team member Joe Roe presented survey results from his latest field season in eastern Jordan.

Molen de Valk windmill in the center of Leiden