Urbanization transforms environments in ways that alter biological evolution. We examined whether urban environmental change drives parallel evolution by sampling 110,019 white clover plants from 6169 populations in 160 cities globally. Plants were assayed for a Mendelian antiherbivore defense that also affects tolerance to abiotic stressors. Urban-rural gradients were associated with the evolution of clines in defense in 47% of cities throughout the world. Variation in the strength of clines was explained by environmental changes in drought stress and vegetation cover that varied among cities. Sequencing 2074 genomes from 26 cities revealed that the evolution of urban-rural clines was best explained by adaptive evolution, but the degree of parallel adaptation varied among cities. Our results demonstrate that urbanization leads to adaptation at a global scale.

No abstract

No abstract

Peatlands are one of the most important carbon cycle regulatory ecosystems, and are influenced by global climate change. However, studies of this kind of wetland are scarce in southern South America. In this study we performed a detailed analysis of recent accumulation rates of carbon (RERCA) in two types of Sphagnum peatland in Isla Grande de Chiloé (Chile) (42°-43°S and 75°-73°W). Monoliths of peat in continuous depths were analyzed and assigned ages using 210 Pb dating. The results showed a difference between the two types of peatland; the average rate for the anthropogenic peatland (107.34 ±113.9 g C m-2 yr-1) was superior to that of the natural peatland (78.33±77.1 g C m-2 yr-1). The surface profiles (30 cm) clearly revealed the recent rate of carbon accumulation for the past 100 years in Sphagnum peatlands of Northern Patagonia. The rate for the natural peatland is within the range found for ombrotrophic peatlands in the Northern Hemisphere. However, the rate estimated for the anthropogenic peatland was significantly greater than those reported in other parts of the world. Our results provide evidence of the importance of these unique ecosystems in the carbon accumulation process.

No abstract