Of Mine Revegetation and Speciation

In 1965 in Janis Antonovics began studying the sympatric speciation of vernal sweet grass (Anthoxanthum odoratum) at the Trelogan mine in Flintshire, Northern Wales. Trelogan mine was established in the mid nineteenth century and reworked in the last quarter of that century before closing in 1898. It had been noticed in 1963 the difference in appearance of the grass around the mine and mine tailings from that of the grass in the surrounding pasture. The mine was separated from the pasture by a wall and other small populations of the mine species had grown in patches near the mine. Antonovics has spent the last 40+ years studying these grasses.

One of the first differences that were noted was the metal tolerance of the variety of A. odoratum near the mine compared to the intolerance of the grass of the pasture. Further, it was observed that the two populations of grasses had developed prezygotic barriers in the time since divergence in the form of different flowering times. Another difference seen between the two populations was the evidence of chlorosis in the grass near the mine tailings caused by high levels of zinc and lead in the soil.

Antonovics's findings have remained consistent throughout the past forty years of study in this area. This remains true even when the two species were removed from their natural settings and cultivated in a garden setting instead. The greatest amount of isolation was seen at the mine boundary, creating a barrier of species to help resist interbreeding. Even the clusters of metal tolerant grass outside of the mine were found to exist only on mine tailings, as they had leeched from the mine on higher ground to lower areas.

The new species of A. odoratum is what is known as a bioreporter. It provides a signal of metal rich soil. Bioreporters especially come in handy in the revegetation of mines in the land reclamation process and can be studied to help determine metal levels in soil of area being reclaimed. The abundance of the metal tolerant sweet grass near the mine today shows that over the last hundred years metal levels in the soil have remained relatively high.

What is so amazing about these findings is that it shows a high level of differentiation in a very short distance and in a very short time period (probably only within the last 100 years). This information refutes the commonly held belief that speciation or evolution requires massive amounts of time in order to occur. Instead, we are shown that speciation can happen in what in the grand scheme of things is an instant. Indeed, we, as a species, have come a long way from the flat earth, fixed species, divinely created system of existence that was so prevalent less than 200 years ago.

Works cited

1) Antonovics, Janis. "Evolution in closely adjacent plant populations X: long-term persistence of prereproductive isolation at a mine boundary." Heredity. Vol.96 n.1. (2006). Pp. 33-37. published online 26 Apr 2006.