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C L I F F O H M AR T Vineyard View How is Biodiversity Measured? I ncreasing biodiversity in and around vineyards is often touted as one of the goals of sustainable winegrowing, and it is frequently mentioned as an important component of other sustainable cropping systems. The term biodiversity is simple, but it describes an extremely important and complex property of a biological community. I often wonder how many people really understand what biodiversity means and how it is measured. When hearing the word biodiversity, many GovtLiaison_Dir08 people likely think of 11/29/07 with fur creatures 2:00 PM or feathers, which is understandable. TTB LABEL APPROVALS Low per-label costs Gov't. Liaison Negotiations or Footwork Reasonable Hourly Rates TRADEMARK SEARCHES As Low as $185 Your trade names or designs are searched at the U.S. Patent Office to help establish valuable ownership or avoid costly legal liability. Over 100 years' total staff experience handling every government liaison need for industry. Phone or write for details. 200 N. Glebe Rd., Suite 321 Arlington, Virginia 22203 Phone: (703) 524-8200 Fax: 525-8451 TOLL-FREE 1-800-642-6564 Major Credit Cards Accepted www.trademarkinfo.com Since 1957 82 W in es & V i ne s APR I L 2 013 However, the furred and feathered animals in and around vineyards are just a part of biodiversity. Because of the importance of biodiversity in biological communities (and the fact that many of us frequently use the term), I am devoting this column to defining biodiversity, describing why it is important for ecosystem function and presenting some scientific methods for measuring it. What is biodiversity? When I was in college (which was quite Pag a while ago now), the "bible" for ideas, definitions and scientific approaches to all aspects of ecology was T.R.E. Southwood's textbook "Ecological Methods." In my 1978 edition, he devoted a chapter to the topic of diversity. The word biodiversity is a more recent term that means the same thing. The definition of biodiversity is the variety of animal and plant species in a community. However, as Southwood points out, the concept is one of those common-sense ideas that prove elusive and multifaceted when it comes to precise quantification. If we are going to discuss biodiversity in terms of its importance in winegrowing, then it is important we speak of it in terms of quantification. If we cannot quantify biodiversity, how do we know it is at an adequate level? Or, how do we know it is increasing as we implement practices that supposedly enhance it? You will discover later in this column that quantifying biodiversity is not easy. But first, let's further discuss what it is. When sampling the animals and plants in a community, a few species are represented by a lot of individuals, and a lot of species are represented by only a few. This phenomenon highlights two important aspects of biodiversity: 1) species richness, which is the number of species present in a community; and 2) species evenness, which is the number of individuals present from each species. These two aspects make measuring and interpreting biodiversity a challenge. Is it more important to have a high species richness or species evenness? If a given site has a range of habitats made up of a variety of soils and plants, such as a hillside with a vineyard, a meadow and then a grove of trees, we would expect a larger number of animal species to be present than in a community with a narrow range of soils and plants, such as a vineyard on flat ground with a uniform soil type. That is because there are more ecological niches present on a site with more varied habitats. The hillside mentioned above has vines, grasses, shrubs and trees that provide opportunities for a greater number of different species to exist, while the flat ground site has only vines and grasses. The extreme case in the range of habitat variation accompanied with a high biodiversity is a tropical rainforest, which has many species of plants and many layers of forest canopy, providing an array of different niches. These areas Highlights • iodiversity has two important aspects: B species richness, which is the number of species present in the community, and species evenness, which is the number of individuals of each species. • have never seen anyone actually use I a biodiversity index to calculate it for a given biological community. • ue to the difficulty of calculating a bioD diversity index, monitoring an indicator species may be an alternative.