The EU’s Biodiversity Strategy for 2030 aims to address the main drivers of biodiversity loss, with invasive alien species (IAS) as one of the key factors. Among the many exotic plants introduced over the past two centuries into the Mediterranean basin, some Acacia spp. are among the most aggressive. The genus Acacia has more than 1,350 species, most of which have an Australian origin.
In Portugal, acacias were introduced in the 18th century as ornamental plants and for specific purposes such as slope fixation and barriers to the expansion of coastal dune areas. In recent decades, acacias have come to be regarded as an invasive species. They self-reproduce, occupying new areas, creating new occupation spots that are stable in space and time with negative environmental and economic consequences (e.g., loss of diversity and alteration of the wildfire regime). It is estimated that these species already occupy 60 thousand ha and cause annual losses of 10 million euros. Therefore, in Decree-Law 92/2019, all species of the genus of Acacia in Portugal were recognised as an exotic invader. Also, in Portugal, a variety of projects / activities are carried out annually to research and control acacia.
In order to tackle this issue, there is a growing demand for cross-functional projects that bring together specialists from different fields looking for answers and solutions. An example of one of these projects is ACACIA4FIREPREV, which combines biologists, chemists, forestry and education specialists, not only to promote the most efficient use of acacia biomass, helping to reduce the risk of wildfires but also to raise public awareness of the threats and need to control these species invasions. This approach helps to promote innovative methods enhancing this project. For instance, in May 2021 while working with a target audience within the scope of citizen science activities, was used, for the first time, the BioBlitz method (intense biological survey), in order to detect and identify acacias.
The BioBlitz was first coined by U.S. National Park Service naturalists. The main aim is to find and identify the maximum number of species, in a specific area, over a short period of time, functioning as a biological inventory. There is a strong public component to many BioBlitzes, with the goal of getting people interested in biodiversity. Usually, plant identification is carried out by biologists and botanists. Hence, one of the things that makes BioBlitz special is that, in addition to scientists, many families, students, teachers and other members of the community participate in it.
Having conducted a section on the identification of acacias and other weed plants within the framework of BioBlitz da Tapada, the ACACIA4FIREPREV members sought to draw attention not only to the diversity of the Tapada da Ajuda Botanical Park (located in the center of Lisbon) but also to its biological threats.