Livestock affects the evolutionary potential of native plant species in Monte Desert

D. JAUME; I. PELLIZA; M. TADEY; C. P. SOUTO

Congreso; II Meeting of Systematics, Biogeography, and Evolution; 2021

Understanding how anthropogenic disturbances affect genetic, ecological and evolutionary processes aids the development of sustainable management and conservation strategies, particularly in drylands threatened by desertification. Introduction of domestic livestock in natural areas of arid environments affects the dynamics and stability of plant communities with unpredictable evolutionary consequences. We hypothesize that livestock grazing exerts selective pressures, negatively affecting genetic diversity and fitness of consumed plants, and also of their offspring. We predict lower genetic diversity (heterozygosity and allelic diversity) and fitness (reproductive success and seedling vigor). We collected foliage and seeds of Atriplex lampa, a dominant consumed bush of the Patagonian Monte Desert, from two rangelands with High and Low Stocking Level, measuring fitness (height and diameter, % reproductive branches, seed weight and viable seed proportion). We sowed seeds under common garden conditions, and evaluated offspring vigor as height and branch number. We calculated standard population genetic parameters using microsatellite markers. As expected, we detected significantly lower genetic diversity in rangelands with HSL (He= 0.354 and Ad= 0.251) compared to those with LSL (He = 0.441 and Ad = 0.291) (all p