Research undertaken by Trinity academics has revealed, for the first time, the numerous interacting factors that reveal why species diversity and productivity vary so enormously across the grasslands of our planet.
With grasslands covering approximately one-third of the world’s ice-free land and relied upon for agriculture and supporting livestock for meat and dairy products, such research should prove very beneficial for farming and food production.
Growing concerns over the environmental impact and growing cost of fertilisers mean that the findings by Trinity researchers are significant, with the suggestion that diversity both in Ireland and across the globe could boost the productivity of grasslands in a similar way to how fertilisers have done so in the past.
In a press release, Yvonne Buckley, Professor of Zoology in Trinity’s School of Natural Sciences, said: “We have traditionally relied very heavily on fertilisers for increasing productivity in grasslands but by paying attention to species diversity grasslands can produce the multiple benefits that we need, such as habitat for critical pollinators, while still maintaining productivity.”
The findings, published in the journal Nature, show that Irish agriculture is heavily dependent on pastures which vary from low diversity pastures on heavily fertilised soils to to some of the world’s most diverse pastures, which exist on the nutrient poor soils of The Burren, Co. Clare.
The researchers findings suggest that across all pasture types, an increase in species diversity can result in an increased pasture productivity. However, an increase in fertilisation results in lower species diversity, even though productivity levels are increased, according to the findings. This leaves two potential avenues for managers of pastures to go down to increase productivity – increase species diversity or increase fertilisation levels.
Prof Buckley emphasised the importance of such a study: “In a world where fuel prices are increasing rapidly and pushing up the cost of fertilisers, the use of species diversity to increase and maintain productivity will become increasingly critical. We need to understand the effects of species diversity in Irish pastures in order to set an appropriate course for sustainable intensification.”
In ecological terms, these findings show that the main factors determining the number of species to be found in a grassland are soil suitability and local climatic suitability, as well as determining how much biomass it will produce. However, the same conditions are not necessarily beneficial for diversity and biomass production.
Professor Buckley added: “This research reconciles decades of debate as to which mechanism was strongest and explains over 60% of the variation in diversity seen between sites worldwide.”
