Organic Agriculture Boosts Biodiversity On Farmlands

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Does organic farming foster biodiversity? The answer is yes, however, the number of habitats on the land plays an important role alongside the type and intensity of farming practices. These are the findings of an international study that looked at ten regions in Europe and two in Africa. The results has been published in Nature Communications. The study shows that even organic farms have to actively support biodiversity by, for example, conserving different habitats on their holdings.

An international team, including scientists from Technische Universität München (TUM), investigated the contribution of organic farming to supporting farmland biodiversity between 2010 and 2013. Researchers wanted to explore whether organic farms are home to more species than their conventional neighbors. The team used uniform methods across Europe to capture data and analyze it to establish the impact of farming methods and intensity and of landscape features on biodiversity.

“Organic farming is beneficial to the richness of plant and bee species. However, observed benefits concentrate on arable fields,” says TUM’s Prof. Kurt-Jürgen Hülsbergen. His Chair for Organic Agriculture and Agronomy analyzed 16 Bavarian dairy farms.

The study investigated farms in twelve regions with different production systems. In each region, farms were selected randomly, half of them certified organic for at least five years. In Switzerland, grassland-based cattle farms were studied and in Austria the study looked at arable farms. In Italy and Spain, researchers focused on farms with permanent crops such as wine and olives, and on small-scale subsistence farms in Uganda.

More species because of field boundaries

More species were found in organic arable fields than in non-organic fields. In contrast, there was little difference in grasslands or vineyards. Organic farming benefited the four taxonomic groups of plants, earthworms, spiders and bees — which were sampled as surrogates for the multitude of creatures living on farmland — in different ways. In general, more species of plants and bees were found on organic than on non-organic fields, but not more species of spiders and earthworms.

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Deforestation Leaves Fish Undersized And Underfed

Trees on the edge of a lake (Image: EyeWire)
The role forest matter plays in aquatic food chains is a relatively recent discovery

Deforestation is reducing the amount of leaf litter falling into rivers and lakes, resulting in less food being available to fish, a study suggests. Researchers found the amount of food available affected the size of young fish and influenced the number that went on to reach adulthood. The team said the results illustrated a link between watershed protection and healthy freshwater fish populations. The findings have been published in Nature Communications.

“We found fish that had almost 70% of their biomass made from carbon that came from trees and leaves instead of aquatic food chain sources,” explained lead author Andrew Tanentzap from the University of Cambridge’s Department of Plant Sciences.

“While plankton raised on algal carbon is more nutritious, organic carbon from trees washed into lakes is a hugely important food source for freshwater fish, bolstering their diet to ensure good size and strength,” he added.

Size matters

Dr Tanentzap observed: “Where you have more dissolved forest matter you have more bacteria, more bacteria equals more zooplankton.

“Areas with the most zooplankton had the largest, fattest fish,” he added, referring to the study’s results.

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