ECOLOGY IN SPACE AND TIME: UTILIZING GEOGRAPHIC INFORMATION SYSTEMS TO RECONSTRUCT PALEOENVIRONMENTS FROM TOOTH WEAR PATTERNS OF GAZELLES IN ISRAEL

Species can be used as a proxy for reconstructing paleoenvironments. Mesowear is the degree of how ungulate teeth wear over time. In browser species, there is little wear, whereas in grazer species, there is greater wear. Nonetheless, few studies have been conducted regarding the relationship between mesowear of ungulate teeth, and how a single species can adapt to environmental parameters over time by shifting its diet.

Mesowear, allows us to categorize a species as either a browser or grazer by measuring the degree of sharpness of the pointed cusps on the molars and assigning an ordinal value based on the wear pattern of the molars. The wear patterns give insight to the types of vegetation the animal ate and therefore is an excellent indicator of the surrounding ecology. A low value indicates the animal consumed mainly browse. An index of a five or six indicates the diet mainly consisted of grasses, causing the teeth to wear down due to the high degree of silica phytoliths in the grasses.

In this study, we tested if the mesowear pattern of the species, Mountain Gazelle, changes along an environmental gradient from wet and cold to hot and dry. Mesowear data were collected on 439 wild shot gazelles from Israel. The location of each gazelle was projected using GIS and different environmental variables retrieved from the GIS database and were attributed to each gazelle based on their GIS coordinates. We also include stable isotope data (C13), indicative of vegetation type. Thus, each gazelle has a single data point including location (coordinates), mesowear, rainfall, temperature, as well as isotope data which measures C₃ and C₄ plant ratio in the diet of the gazelles.

The mesowear and environmental factors were correlated using a Mantel test to find the relationship between wear patterns of the teeth, rainfall and temperature, vegetation patterns and several other environmental and climatic factors.

Results suggests that there is a correlation between climate factors and mesowear, specifically temperature and vegetation structure. This study suggests that this method has the potential to use single species mesowear as a paleoenvironmental proxy over time and can be used as an important tool in geology and archaeology.