**1. Introduction**

The natural grasslands of the arid and semiarid zones are nonarable land due to climatic, edaphic, or topographic limitations, which are covered by native and/or

naturalized vegetation. They can be used as fodder for domestic and wild livestock, as well as to extract water and wood, and for recreational purposes [1]. Likewise, a characteristic of the natural grasslands of Argentine Patagonia (as well as much of the South American Arid Diagonal) is that different biological forms coexist (shrubs, subshrubs, herbaceous eudicots, and grasses) [2–4]. In these ecosystems, it is necessary to use an ecological evaluation method that considers the different biological forms that make up that plant community and that allows differentiating the forms present regardless of whether they are foragers or not, and whether they are present in all seasons of the year or not. That is, the method must reflect the comprehensive diversity present in the area, beyond the uses assigned to each of the species that make up the identified diversity indices (such as wild herbivory or livestock).

Starting in 1995, the Herbarium Trelew work team, referred in the following sections as HTW, used a variety of methods in the field for the flora censuses carried out, according to specific work requirements. Then, starting in 2002, the Pastoral Value Method [2–4], known in the following sections as PVM, is integrated into the methodologies to calculate the ecological parameters considering results and data obtained from the structure of the vegetation, forage productivity, and livestock receptivity.

From 2005 to 2009, it was adapted by the HTW work team gradually the way in which the data were collected based on: the need to generate specific data for the different lines of work that made up the HTW (research, project development, education, professional training, university training, and environmental services), the characteristics of arid and semiarid zones, the floristic composition observed, the field experience by the work staff, the observations in the floristic interactions, and the bases of conservation and preservation to be considered on the identified vegetation units and landscape units. The PVM was thus transformed into a post for obtaining and assessing new results and new horizons of botanical interpretation, expanding data collection not only to considerations of vegetation structure, forage productivity, and animal receptivity, but also to considerations of the type holistic ones related to plant ecology and eco-physiology for arid, semiarid, and subhumid zones. There is a change in the observation for data collection, moving from an exclusive livestock and productive approach to a multidisciplinary botanical, biological, ecological, physiological, and environmental approach, thus considering a new conservationist and protectionist point of view of the environments to evaluate.

In the PVM, the observations focus on the recording, which plants are available for livestock consumption, not only if they are young branches but also the height of the grazing animal and annual plants are not considered in the survey. On the other hand, in the Floristic-Holistic Method, called in the next sections as FHM, the entire flora is surveyed, regardless of the height of the plants or whether it is a young or old branch, focusing the observation mainly on the data of plants considering the presence and if they are alive. Starting in 2010, the FHM began to take hold, which is used to date in the active lines of work of the Botany Laboratory and HTW.

Since the 1990s, by the HTW work team, the published qualitative and quantitative methods have been adapted based on the experimental requirements with the aim of obtaining a modified method that has a conservationist and protectionist vision of the flora of the surveyed sites. It was also sought that the exposed method be useful to different types of applications in the field and diverse scopes in different areas of science. In this way, a method is obtained that considers and groups several methods in a complete way, feasible for application and analysis, applicable in terrestrial ecosystems for arid, semiarid, and subhumid zones, taking into account the

*The Floristic-Holistic Method for Arid, Semiarid, and Subhumid Areas: A Tool… DOI: http://dx.doi.org/10.5772/intechopen.106226*

visualization and understanding requirements of existing ecological dynamics and relationships to consider when making decisions on conservation, protection, planning, and management, which allow sustainable use of ecosystem goods and services in a systemic and holistic way. It is intended to express the path traveled both in field work and in office work in the last two decades by the HTW, based on the integration of qualitative and quantitative methods used historically, as they were adapted based on the experimental requirements, in view of the creation of the Floristic-Holistic Method that points toward a conservationist and protectionist vision of the flora of the surveyed sites.
