Biodiversity indices - cropland

Biodiversity is related to the species richness, density, and diversity of an ecosystem. One of the impacts of land desertification is loss in biodiversity. If an ecosystem is overexploited, the consequence is the loss of biodiversity expressed by direct loss of plant species and the animals associated with them. Biodiversity indices are used to express the change in biodiversity.

Aim of the method/technique	The proposed technique aims to characterized change in biodiversity on landscape units.
Scale – spatial and temporal	Measurements of biodiversity indices at field level are inappropriate for the assessment of cropland biological diversity. Therefore, studies on biodiversity should focus at landscape level.
Brief description	Biodiversity indices in cropland regions can be defined by various methodologies. Various studies (Benton et al. 2003, Hendrickx 2007, Persson et al. 2010, Filippi-Codacioni et al.2010) have shown that  regional diversity (?-diversity) correlates with turnover diversity (ß-diversity) rather than local diversity (a-diversity). Therefore, since cropland biological diversity is beyond the scope (and probably the resources available) of the project, it is suggested to use landscape heterogeneity combined with an index of management intensity as a surrogate to assess it. Moreover, farmland landscape heterogeneity and management intensity are important indices of other aspects of the system as well. The proposed methodology is to select randomly within the predominantly agricultural area of the study site, three replicate landscape units of 1X1 km. Within these areas, detailed maps of agricultural use can be constructed at the field level. The typology of the use has to be formalized so that it is consistent between areas (e.g. olive groves, vines, citrus orchards, arable fields predominantly under wheat cultivation etc.). The linear elements within the landscape (e.g. watercourses, hedgerows etc.) should be also mapped. Based on these data, a number of landscape indices can be easily calculated. Apart from the landscape composition and structure, a value reflecting management intensity should be attributed to each field. Relevant data to estimate a combined index include nitrogen inputs and number of pesticide applications (Herzog et al. 2006). It is suggested that in the case of soil cultivation and irrigation, at least, must be included as well. Since management intensity will be probably be assessed also for other purposes the classes as those proposed in DESERTLINKS project (DIS4ME 2005) should be used.
Data requirements	The required data are: land use intensity maps, aerial photographs, remote sensing images at high and medium spatial resolution. The biological diversity will be defined by field observations, and interpretation of aerial photographs.
Main applications in cropland regions	Description of biodiversity indices of a cropland ecosystem can be useful in assessing the impacts of various responses to LEDD.
Strengths and weaknesses	Defining biodiversity requires expertise in biology with the ability. Strengths are referred to the capability to apply very efficient statistical analysis of the defining plant species distribution. A weakness is the complete spatial and temporal availability of data.

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