As farms across the globe continue to shift toward organic agricultural practices, new research suggests that this transition may have unexpected effects on bat populations. The study has uncovered evidence that during the transition period to organic farming, bat activity is substantially reduced.
This surprising discovery highlights the intricate interconnectedness of ecosystems and raises questions about how best to manage farming transitions to benefit biodiversity.
While it has long been recognized that organic farming fosters greater biodiversity than conventional farming, less is known about the impact of the transition period on local wildlife.
Traditional farming heavily relies on substances such as pesticides, herbicides, and fertilizers which can be detrimental to many species. As farms convert to organic practices, these substances are removed, leaving a gap that some elements of biodiversity may struggle to bridge.
To gain insights into this, the researchers turned their focus to bats – specifically, insect-eating bats living in the citrus orchards of Cyprus.
Across 22 matched pairs of citrus orchards, the team monitored the activity of four bat species: Kuhl’s pipistrelle (P. kuhlii), Savi’s pipistrelle (H. savii), common bent-wing (M. schreibersii), and common pipistrelle (P. pipistrellus).
These observations allowed them to compare bat activity at certified organic farms with conventional farms, and those in transition to organic practices
The study revealed that the activity of three of the four bat species was notably lower at farms in the transition period compared to those maintaining conventional practices.
However, once the transition to organic farming was complete, bat activity increased, indicating a “time-lag” before the organic biodiversity boost for the most abundant bat species.
The researchers, initially anticipating positive effects from the onset of organic farming transition, were taken aback by these results.
“We can’t be certain why bats are negatively affected, but previous research suggests soil can suffer – with knock-on effects for other wildlife – when fertilisers, pesticides and other aspects of conventional farming stop,” said study co-author Penelope Fialas, from the University of Exeter.
Fialas suggested that the soil and wider ecosystem might need time to recover from the abrupt cessation of conventional farming inputs.
With these findings at hand, Fialas underlined the importance of carefully managing the transition to organic farming. Avoiding simultaneous transitions at neighboring farms could help wildlife find alternative habitats while each farm switches its methods, thereby reducing potential negative effects on biodiversity.
“We’ve long known that organic farms often harbour higher biodiversity than otherwise similar conventional farms,” said Gareth Jones from the University of Bristol.
“The transition to organic farming has been little studied, however, and determining if the detrimental effects during transition observed here hold for other animals and plants would be an interesting future research project.”
Notably, the study also found that the presence of “semi-natural” areas surrounding the farms did not influence these differences in bat activity. This may challenge some existing beliefs about the mitigating effects of these areas on changes in biodiversity during farming transitions.
The research was partially funded by the University of Göttingen and has been published in the Journal of Applied Ecology.
Organic farming is a method of crop and livestock production that involves much more than choosing not to use pesticides, fertilizers, genetically modified organisms, antibiotics, and growth hormones. Organic farming can be defined as:
An integrated farming system that strives for sustainability, the enhancement of soil fertility and biological diversity while, with rare exceptions, prohibiting synthetic pesticides, antibiotics, synthetic fertilizers, genetically modified organisms, and growth hormones.
Organic farming promotes the use of crop rotations and cover crops and encourages balanced host/predator relationships. It offers benefits like biodiversity, soil health improvement, lower levels of pollutants in groundwater, better taste, and possibly, nutritional benefits.
However, it also poses its own suite of environmental challenges. For example, due to the current low yields of organic farming, wide-scale adoption could require additional land to be converted for farming use.
Here are a few key principles and practices typically associated with organic farming:
Organic farming emphasizes the use of compost, green manure, and organic fertilizer to nourish the soil that crops are grown in. The health of the soil is a critical component in organic farming, and practices like crop rotation and intercropping are used to prevent the depletion of soil nutrients.
Organic farming doesn’t use synthetic weedkillers. Instead, organic farmers might plant fast-growing species to outcompete weeds, or use physical methods such as hand weeding or flame weeding.
Organic farming typically relies on the principle of biodiversity and the creation of a balanced ecosystem to control pests. This could include the use of insects that prey on crop pests, or using disease-resistant crop varieties. Some organic farmers might also use certain natural pesticides.
Organic standards for livestock involve a range of factors, including providing outdoor access for animals, using organic feed, and limiting the use of antibiotics.
Organic standards generally prohibit the use of genetically modified organisms (GMOs). This includes both the crops grown and the feed given to livestock.
A key principle of organic farming is the idea of sustainability. This involves farming practices that help maintain ecological balance, preventing soil depletion or the loss of biodiversity, and reducing the use of non-renewable resources.