Biodiversity in Agriculture

Biodiversity is a term used to describe the enormous variety of life on Earth. It can be used more specifically to refer to all of the species in one region or ecosystem. Biodiversity refers to every living thing, including plants, bacteria, animals, and humans. Scientists have estimated that there are around 8.7 million species of plants and animals in existence.[1]

Biodiversity helps farmers grow food.

Agricultural fields function like ecosystems and are healthiest with high biodiversity. A farm with high biodiversity provides habitat by growing many types of crops and planting native plants. A high variety of crops, grasses, and shrubs occupying a farm increases the number of helpful insects that live there. More helpful insects result in more food being grown and less use of chemicals that can cause pollution.

Livestock positively impact biodiversity.

Livestock, especially ruminants, can have a positive impact on biodiversity and soil carbon via the “maintenance of permanent grassland and hedges and optimised use of manure”.

One theory holds that plant-hungry animals help shape ecosystems by mowing down dominant plants that might smother other plants, thus enhancing biodiversity—but only if the area is lush. A new study shows that this might not be entirely true.

Researchers synthesised data from more than 250 vegetation-heavy areas, examining areas where large herbivores graze and areas they don’t.

“Large herbivore populations are in decline in ecosystems across the globe, and so understanding how these declines are likely to affect biodiversity is really important,” says co-author Todd Palmer, a biologist at the University of Florida.

By comparing data on the effects of herbivores on plant communities across a wide range of productivity, the researchers found that the effects of grazing animals on biodiversity could be predicted by understanding the impact that herbivory has on plant dominance.

When grazing animals reduced dominance by feeding on abundant species that appealed to their tastes, the grazers increased biodiversity by freeing up resources for other, less dominant plant species. However, in areas where the most abundant plant species are resistant to grazing, herbivores increased dominance by feeding on the rare and tasty species, thereby reducing biodiversity.

The results suggest that management of dominance, not of grazing activity per se, is key to conserving biodiversity.[2]

‘Livestock make meadows and meadows make livestock’

Trevor Dines, a botanical specialist with Plantlife, a UK conservation charity working at home and abroad to save threatened wildflowers, plants and fungi, reiterated the importance of grassland areas as “unique crucibles of biodiversity”.

As well as housing thousands of species of pollinators and other insects, Dines also highlighted the importance of meadows for storing carbon.

“Meadows are more than just havens for wildlife; their soils sequester as much carbon as woodland soils and they’re better at capturing floodwaters and reducing nitrogen leaching than intensively farmed grasslands.”

And these meadows rely on livestock to thrive, according to the plant expert.[3] He pointed out that the benefits go both ways, with species-rich grasslands able to offer livestock a healthy diet higher in minerals and amino acids, thus able to sustain more productive animals.

[1] Biodiversity | National Geographic Society

[2] Change in dominance determines herbivore effects on plant biodiversity | Nature Ecology & Evolution

[3] Plant biodiversity suffers without livestock grazing, says expert – EURACTIV.com