Advanced

Does organic farming lead to taxonomically more distinct communities compared to conventional farming?

Corlett, Bianca (2012) BIOM24 20121
Degree Projects in Biology
Abstract
Abstract

Agricultural intensification is causing a worldwide loss in biodiversity, and organic farming has been proposed as a valid method for preserving it. Studies have shown that organic farming increases species abundances, however the taxonomic breadth of communities may be an additional important biodiversity measure which is not affected by study intensity or sample size. The aim of this study was to examine if the pattern of increased bird, generalist predator, and flower--‐visiting insect biodiversity with organic farming was still evident if information about the taxonomic relatedness between species in a community was included in the analysis. A literature search was conducted in order to gather data sets from studies... (More)
Abstract

Agricultural intensification is causing a worldwide loss in biodiversity, and organic farming has been proposed as a valid method for preserving it. Studies have shown that organic farming increases species abundances, however the taxonomic breadth of communities may be an additional important biodiversity measure which is not affected by study intensity or sample size. The aim of this study was to examine if the pattern of increased bird, generalist predator, and flower--‐visiting insect biodiversity with organic farming was still evident if information about the taxonomic relatedness between species in a community was included in the analysis. A literature search was conducted in order to gather data sets from studies comparing animal communities in organic versus conventional European cereal farms. Pair--‐wise and community composition comparisons were made between organic and conventional systems, and variation was examined between study site coordinates and functional groups. No significant differences in species richness or taxonomic breadth were found in organic systems versus conventional systems, although bird and butterfly biodiversity measures showed weak relationships to farming systems. There were no significant effects of spatial location on biodiversity measures. However, community composition differed between farming systems, with winners and losers among the analysed species. This pan--‐ uropean study did not suggest a positive effect of organic farming on species numbers or the taxonomic breadth of communities, however biodiversity effects are more pronounced if abundances are also considered. Further studies should include information about landscape complexity and characteristics, and animal functional traits.

Popular science summary:
Animal biodiversity in organic farms:
does taxonomic information matter?

Modern agriculture is rapidly expanding and lowering biodiversity in agricultural animal communities. Organic farming is thought to be less harmful due to the use of organic fertilizers and lack of pesticides, and is a strategy to preserve animal biodiversity.

Biodiversity can be defined as the diversity of species in an ecosystem. Generally, higher biodiversity is a positive factor in ecosystems of all kinds. The most common measure to quantify biodiversity in scientific literature is species richness: the number of different species present in a certain area.

While species richness is an important factor in biodiversity, many scientific articles neglect to include taxonomic information about the species being discussed. Taxonomy is the study of species classification, and taxonomic information can be very useful in the context of ecosystem diversity. "Taxonomic breadth" is a measure that can be used alongside species richness, and explains how closely species are related within a community.

To examine whether organic farming truly did benefit animal biodiversity, this thesis project examined the species richness and taxonomic breadth of bird, generalist predator (beetles and spiders), and flower-visiting insect communities in organic versus conventional cereal farms in Europe via a literature search.

In the 38 data sets that were analyzed, it was found that organic farming did not increase species richness or taxonomic breadth. In fact, bird diversity appeared to decrease in organic farms. These unexpected results are likely due to the lack of information about landscape characteristics in the analysis. This study illustrates that animal biodiversity is not able to be quantified simply by species richness or taxonomic breadth alone - landscape characteristics are a large factor in animal biodiversity, and should be included in the analysis in order to get accurate results.








Advisor: Klaus Birkhofer, Johan Ekroos, and Henrik Smith
Master´s Degree Project, 30 credits in Ecology (Biodiversity and Conservation Science) 2012
Department of Biology, Lund University (Less)
Please use this url to cite or link to this publication:
author
Corlett, Bianca
supervisor
organization
course
BIOM24 20121
year
type
H2 - Master's Degree (Two Years)
subject
language
English
id
3732460
date added to LUP
2013-04-30 12:51:26
date last changed
2013-04-30 12:51:26
@misc{3732460,
  abstract     = {Abstract

Agricultural intensification is causing a worldwide loss in biodiversity, and organic farming has been proposed as a valid method for preserving it. Studies have shown that organic farming increases species abundances, however the taxonomic breadth of communities may be an additional important biodiversity measure which is not affected by study intensity or sample size. The aim of this study was to examine if the pattern of increased bird, generalist predator, and flower--‐visiting insect biodiversity with organic farming was still evident if information about the taxonomic relatedness between species in a community was included in the analysis. A literature search was conducted in order to gather data sets from studies comparing animal communities in organic versus conventional European cereal farms. Pair--‐wise and community composition comparisons were made between organic and conventional systems, and variation was examined between study site coordinates and functional groups. No significant differences in species richness or taxonomic breadth were found in organic systems versus conventional systems, although bird and butterfly biodiversity measures showed weak relationships to farming systems. There were no significant effects of spatial location on biodiversity measures. However, community composition differed between farming systems, with winners and losers among the analysed species. This pan--‐ uropean study did not suggest a positive effect of organic farming on species numbers or the taxonomic breadth of communities, however biodiversity effects are more pronounced if abundances are also considered. Further studies should include information about landscape complexity and characteristics, and animal functional traits.

Popular science summary:
Animal biodiversity in organic farms: 
does taxonomic information matter?

Modern agriculture is rapidly expanding and lowering biodiversity in agricultural animal communities. Organic farming is thought to be less harmful due to the use of organic fertilizers and lack of pesticides, and is a strategy to preserve animal biodiversity. 

Biodiversity can be defined as the diversity of species in an ecosystem. Generally, higher biodiversity is a positive factor in ecosystems of all kinds. The most common measure to quantify biodiversity in scientific literature is species richness: the number of different species present in a certain area.

While species richness is an important factor in biodiversity, many scientific articles neglect to include taxonomic information about the species being discussed. Taxonomy is the study of species classification, and taxonomic information can be very useful in the context of ecosystem diversity. "Taxonomic breadth" is a measure that can be used alongside species richness, and explains how closely species are related within a community.

To examine whether organic farming truly did benefit animal biodiversity, this thesis project examined the species richness and taxonomic breadth of bird, generalist predator (beetles and spiders), and flower-visiting insect communities in organic versus conventional cereal farms in Europe via a literature search.

In the 38 data sets that were analyzed, it was found that organic farming did not increase species richness or taxonomic breadth. In fact, bird diversity appeared to decrease in organic farms. These unexpected results are likely due to the lack of information about landscape characteristics in the analysis. This study illustrates that animal biodiversity is not able to be quantified simply by species richness or taxonomic breadth alone - landscape characteristics are a large factor in animal biodiversity, and should be included in the analysis in order to get accurate results.




 



Advisor: Klaus Birkhofer, Johan Ekroos, and Henrik Smith
Master´s Degree Project, 30 credits in Ecology (Biodiversity and Conservation Science) 2012
Department of Biology, Lund University},
  author       = {Corlett, Bianca},
  language     = {eng},
  note         = {Student Paper},
  title        = {Does organic farming lead to taxonomically more distinct communities compared to conventional farming?},
  year         = {2012},
}