Background:

Historically, in biology, there have been discrepancies when considering certain taxa within the “native” or “exotic” categories in particular geographic areas.

Questions and/or Hypotheses:

Do the taxa have inherent qualities that allow establishing formalisms consistent with a principle of priority as a criterion to solve problems derivates of the categorization "native-exotic"?

Studied species/ Data description /Mathematical model:

Eucalyptus globulus, Phytolacca dioica, Prosopis alba, Schinus longifolius and Tipuana tipu were used as reference species to apply mathematical models called “Ancestrality Indices” that allow formalizing the degree of ancestral quality of a taxon in a given area.

Site and years of study:

Three areas geographically associated but with discordant characteristics were selected. This work was carried out between 2017 and 2022.

Methods:

Two types of complementary indices are proposed. The "Índice de Ancestralidad Binario", which starts from the classic distinction of "native-exotic" species and is coded in binary form. The “Scalar Ancestry Index”, which is based on the development of two criteria: a spatial one (“distance to the area of origin”) and a temporal one (“permanence time”).

Results:

Tables were obtained with the indices mentioned for the species and areas chosen.

Conclusions:

These indices will be useful, for example, when it is necessary to make decisions that may negatively affect ecosystems, considering the history and identity of the site. The indices would also be fundamental as a stimulus to research on associated themes and to compose the ecological stratigraphy of an area.