Conservation Biology hasan impact factor of 4.842. The impact factor is determined by the averageamount of times a journal has been cited within papers throughout a given year.
If a journal has a high impact factor, the journal has been cited numeroustimes, whereas a low impact factor would mean that it was not cited that often.This article by Beecher et al. has been cited 112 times since being publishedin 2002. A paper that has used Beecher’s article is cited in the following: Wickramasinghe,L. P., Harris, S., Jones, G. and Vaughan, N.
(2003), Bat activity and speciesrichness on organic and conventional farms: impact of agriculturalintensification. Journal of AppliedEcology, 40: 984–993. doi:10.1111/j.1365-2664.
Wildlifeconservation and farmland management have common interests when it comes to theenrichment of bird habitats and the natural elimination of farmland pests. TheUnited States is covered in almost one-fifth of croplands which have beenchemically controlled over the past two generations. Birds will use these areasfor daily activities such as, breeding, foraging, migration, and winteringactivities. Most birds will use the uncultivated field edges, but there aresome birds that will still forage in the crops.
Field quality can be determinedby pesticide use. Pesticides can affect the resources for foraging and can havenegative effects on organisms. With the use of organic farming, which does notuse harsh fertilizers and pesticides, cultural and mechanical practices arebeing used.
Beecher et al. uses a statement from the National Research Councilthat states: “alternative agriculture sustains and enhances rather than reducesand simplifies the biological interactions” (2002). This study examined thebird communities in paired nonorganic and organic cornfields to see which typeof farmland the birds would prefer. A study done by Dahlgren and Chamberlainfound that there was a greater species richness and abundance of birds withinorganic farms than on nonorganic farms. Beecher et al. have come up with thefollowing hypothesis for this paper: “Modifying farm-management practices,especially near field edges where bird activity is concentrated, may enhancethe conservation of birds and their potential predation on crop pests” (2002).
Beecheret al. studied the bird populations within pairs of nonorganic and organiccrops on privately owned farms in east-central Nebraska. The farms were locatedat the western edge of the dryland corn belt within the central Great Plains. Theyran this study in two consecutive years in early summer, June 6th,1995 to July 9th, 1995 and June 12th, 1996 to July 18th,1996 and late summer from August 4th, 1995 to September 4th,1995 and July 31st, 1996 to September 7th, 1996.
In the1995 study, there were 16 sites (8 pairs) in the early summer session and 12sites (6 pairs) in the late summer session. In the 1996 study, there was 14sites (7 pairs) in both early and late summer sessions. The pairs consisted ofan organic and nonorganic farmland with like features. During the study therewas one researcher, Dr. Beecher, who would count the birds within the givenareas, so it was done the same way every time. While researching they looked atthe bird abundance, species richness, and the make of organic and nonorganicfarmland, which was used to determine the differences in correlation to farmmanagement, biological control of crop pests, and bird conservation efforts.
The nonorganic crops received altered standard management of crop rotation andpesticide use. These fields also received synthetic herbicides and fertilizers.The organic fields were synthetic fertilizer and pesticide free for at least 3consecutive years. Each site in the early summer crops had two lines calledstrip-transect lines, one bordering the edge of the crops and the other was 100meters into the crop. The Beecher would also survey the vegetation adjacent tothe field and 25 meters of the crop perimeter. The total area for both organicand nonorganic fields were 21.5 hectares in 1995 and 19.
6 hectares for organicand 20.9 hectares for nonorganic in 1996. In the late summer sessions, the cornheight caused the strip-transect method to not work, so they used an alteredfixed-distance point counts. This was done by dividing the crops intorectangular or square every 100 meters. There were three to six visits per siteper season between sunrise and then 4 hours later. Paired sites were alwaysvisited on the same days.
The lines were walked at a pace of about 100 metersper every 10 minutes. The point counts lasted for 5 minutes. Birds were countedas they were feeding within the areas or right above the areas (aerialforagers) and nesting birds were counted. The groundcover, tree dispersion, andvegetation was determined by using the Daubenmire frame test. Restrictedmaximum-likelihood estimations were used to compare between the organic andnonorganic migratory and foraging birds. A two-tailed binomial paired t testwas used to see the differences in the organic and nonorganic sites.
Beecheret al found that organic sites had on average a higher mean bird abundance andspecies richness than the nonorganic sites in both early and late summers. Theabundance was 2.6 times more greater and the richness in the surveys was twotimes more in the organic sites. Fifty-four bird species were recorded over thetwo years. Fifty-one species were found in the organic sites and thirty-ninespecies were found in the nonorganic sites. There was a greater abundance and richnessof the foraging guilds (insectivores, omnivores, and granivores) with in theorganic crops than the nonorganic crops in both early and late summers. Theneotropical and short-term birds had more abundance and richness on organic farmscompared to resident birds.
The resident birds had no difference between organicand nonorganic. The results help bolster the hypothesis. Results were explainedwith raw and summarized data. The raw data was given throughout the results sectionand was then summed up at the end of the results section to make it easier to understand.Bar graphs, pie charts, and tables were also used to provide the results informationwithin the article. Theresults of this study show that organic farming can help bird conservation efforts.The overall findings showed that “organic cropland, compared with nonorganiccropland, sustains a greater abundance and species richness of birds acrossforaging and migratory guilds” (2002). This helps to show that their hypothesiswas correct and gives us ways to change for the better of our future.
A 1-year Canadianstudy also showed relatively similar results that showed more birds and specieson an organic cropland and gave the differences to the nonuse of herbicides. Studiesdone by Braae et al. and Christensen et al. found that organic crops had a highercarrying capacity for birds.
The use of organic crops and farms in the future willlead to a more sustainability and conservation of bird species.