Field biologists have found that grassland plants are six times more likely to become out-grown by so-termed “space-invading” species. The research found further that when fertiliser is used the effect is even greater with non-native plants taking over swathes of green spaces.
In many parts of Ireland, grasslands are used for agricultural and for cattle. These areas are composed of native species of grass and plants introduced from other areas (what are termed “exotic species.”) These species are either introduced deliberately, for an agricultural reason, or they arrive by accident, transported by the wind or on the feet of people for example.
With fertilizer use, The Irish Times reports, such chemicals, often nitrogen based, are added to agricultural land to increase crop yield. Long-term use of fertilizer reduces the diversity of plant species. What also happens is that more dominant plant species grow in greater numbers. In many areas of grassland, it is the non-native species that tend to be the dominant types of plant.
The implications of this trend are of economic as well as conservational importance. Many aspects of farming rely on native grasses. Ironically, the activities by farmers in using fertilizers to boost yield could, over time, prove to be counter-productive in that the very species of plant that the farmers want to conserve end up being out-grown by other, less desirable species.
The study was carried out by biologists based at Trinity College, Dublin. The findings have been published in Nature Communications. The paper is titled “Plant species’ origin predicts dominance and response to nutrient enrichment and herbivores in global grasslands.”
In related agriculture news, in the U.K. The Soil Association has raised a warning about a new tendency by farmers to grow maize. This is said to be leading to damage to soils and water. Land put aside for growing corn in England has increased from 8,000 hectares in 1973 to 183,000 hectares in 2014.
