Hero or Villain: The Importance and Impacts of the Genus Juniperus on Ecosystems

The genus Juniperus species is widely distributed in the Northern Hemisphere of the planet Earth. These species are notable for their ability to adapt to extreme environmental conditions, playing a crucial role in ecosystem structure and function. Currently, their expansion is being driven by anthropogenic activities and climate change, posing significant challenges for both control and conservation. The objective of this review was to synthesize the available evidence regarding the ecological importance and impacts of Juniperus on ecosystems, promoting a holistic perspective that contributes to the achievement of the United Nations 2030 Agenda for Sustainable Development. A systematic literature search was conducted using the Scopus database, and only the documents published between 2001 and 2025 were considered for the investigation. The results showed that these species possess a high ecological versatility, favoring their invasive success in disturbed ecosystems, particularly under the influence of climate change and land-use changes. Conversely, Juniperus species facilitate positive ecological outcomes by providing essential ecosystem services that benefit both the human population and the flora and fauna present in these ecosystems. Nevertheless, their expansion also causes negative effects, such as the suppression of herbaceous shrubs and understory cover, alteration of the hydrological function, and accelerated soil erosion, among others. Consequently, the genus Juniperus exhibits a dual ecological role, acting as a hero to many species within these ecosystems, yet a villain to others. In this sense, given its remarkable adaptive dynamism under scenarios of climate change and continuous anthropogenic alterations, it is imperative to promote comprehensive conservation and restoration strategies. These should include ecological monitoring, invasive species control, genetic management, and habitat restoration. Such efforts must be supported by long-term interdisciplinary research to understand and mitigate the ecological, genetic, and social impacts resulting from its expansion. Furthermore, these investigations and strategies must be flexible and locally contextualized to promote genuine ecosystem resilience in the face of the ongoing environmental transformations.