Weeds are vital to the existence of farmland species, study finds

September 29, 2011

Weeds, which are widely deemed as a nuisance plant, are vital to the existence of many farmland species according to a new University of Hull study published in the journal Biological Conservation today.

Since many weeds produce flowers and seed, they are an integral part of our ecosystem and together with other crop and non-crop seeds found on farms, they provide food for over 330 species of insects, birds and animals.

Scientists at the Universities of Hull and Bristol examined the distribution of berries and soil-surface seeds collected over an entire year. They built up the first picture of its kind showing which habitats are the most important and how the seed resources change in different seasons.

Whilst considerable research has linked agricultural intensification with dramatic declines of seed-feeding birds, surprisingly little is known about the wider importance of seeds for other farmland animals, especially insects. Moreover, understanding the dynamics of farmland seed food resources for species of conservation concern is of considerable research interest.

The team of researchers created complex 'food-webs' which linked all farmland insects, birds and mammals which are known to feed on the seeds recorded on a typical organic farm. They used the food-web to identify the key seed-producing plants favoured by most animals. This enabled them to model the impacts of increasing farm management on seed resources and food-web interactions.

Dr Darren Evans, a lecturer in at the University of Hull and who led the research said: "We understand a lot about farmland birds and mammals, but little about the plants and insects that underpin them. In this study, we discovered not only the importance of weed and non-crop species for many farmland animals but that the vast majority of seed-feeding animals on farms are insects, which are often overlooked by conservationists."

The team of researchers converted seed counts into mass and energy estimates; they found that shed seeds and berries available on a single organic farm have can produce a staggering 560 gigajoules of energy.

Dr Evans added: "We show that an increase in farm management intensity can lead to a decline of up to 19% in overall seed biomass and energy, which is presumably why causes many farmland birds to suffer a 'hunger-gap' in mid-winter. Non-farmed habitats such as woodlands and hedgerows are important for seed resources, but we also show that some farmed areas are too".

The team predicted that increased farming intensity can have large cascading effects throughout an entire ecosystem, which can indirectly affect animals associated with the seeds.

The scientists conclude that farmers can maintain or enhance biodiversity by appropriately managing uncultivated, semi-natural habitats such as hedgerows and woodlands but that even small changes to cropped areas, such as allowing some weed species to grow, could have a huge impact on the quantity and variety of seeds available on the farm and the animals that feed on them. They suggest that rather than focussing limited conservation resources on a small number of charismatic species such as birds, an alternative approach is to understand and manage the complex network of interactions on farms and to explore ways of incorporating this into policy.

Explore further: Another reason to drink a nice cup of shade-grown joe

More information: 'Seeds in farmland food-webs: Resource importance, distribution and the impacts of farmland management' Biological Conservation.

Related Stories

Another reason to drink a nice cup of shade-grown joe

December 22, 2008

A new study published in the December 23rd issue of Current Biology, a Cell Press publication, reveals another "eco-friendly" reason to select shade-grown coffee over beans that were grown in the sun: Shade coffee farms not ...

Spread of Western Juniper Seeds Studied

November 5, 2009

(PhysOrg.com) -- Aromatic, evergreen foliage and plump, dusty-blue to nearly purple berries make western juniper appealing, whether it's a small shrub or a lofty tree. The trouble is, during the past 100 years or so, some ...

Beetles play an important role in reducing weeds

July 25, 2011

Researchers funded by the UK Biotechnology and Biological Sciences Research Council and the French Institut National de la Recherche Agronomique (INRA) have found that ground beetles reduce the amount of weed seeds in the ...

Short-lived seed of alpine plants

September 21, 2011

Scientists from the Millennium Seed Bank Partnership have found that the seeds of alpine plants are shorter lived than their lowland relatives. This will have implications for seed conservation strategies for alpine species.

Recommended for you

Most EU nations seek to bar GM crops

October 4, 2015

Nineteen of the 28 EU member states have applied to keep genetically modified crops out of all or part of their territory, the bloc's executive arm said Sunday, the deadline for opting out of new European legislation on GM ...

Ancestral background can be determined by fingerprints

September 28, 2015

A proof-of-concept study finds that it is possible to identify an individual's ancestral background based on his or her fingerprint characteristics – a discovery with significant applications for law enforcement and anthropological ...

Trade in invasive plants is blossoming

October 3, 2015

Every day, hundreds of different plant species—many of them listed as invasive—are traded online worldwide on auction platforms. This exacerbates the problem of uncontrollable biological invasions.


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.