Ecological Modelling of the Macaronesian-Mediterranean Junipers (Juniperus L. Sect. Juniperus) and conservation of the near-endemic tree Juniperus navicularis Gand. - Digital Annex

Digital Annex for the following thesis:

Ferreira, C. (2024) Ecological Modelling of the Macaronesian-Mediterranean Junipers (Juniperus L. Sect. Juniperus) and conservation of the near-endemic tree Juniperus navicularis Gand.

Abstract:

Juniperus L. Sect. Juniperus is a genus in the Cupressaceae family that includes species found in the Macaronesian and Mediterranean regions, known as needle leaved junipers. 

In this study we approached the near endemic J. navicularis, by reviewing its nomenclatural history and applying Species Distribution Models to infer its future suitable areas in the Iberian Peninsula to inform conservation policies of this Near Threatened (IUCN) tree.

We then applied a deeper spatial analysis with a past-to-future narrative, by hindcasting (since the last interglacial period, 130 Kyrs) and forecasting (up to the year 2100) the distribution of eight taxa inside Section Juniperus, using Species Distribution Models to explore their biogeographical and ecological dynamics, inferring about the main ecological drivers that shaped their distribution across eleven periods (seven past, current and three future scenarios). 

Results vary significantly between species. Models applied at a fine-scale (1 km) resolution and a wide range of bioclimatic and edaphic variables, for J. navicularis' show a major decline by 2070, followed by a slight increase of suitable area towards northern latitudes by 2100. This contrasts with Chapter 4, when using a coarser resolution (10 km) and a different variable set, where overall trends reflect global contractions across several species.

Results evidenced by the multispecies approach show an increase in the suitability areas  for J. deltoides, while the Macaronesian J. brevifolia and J. cedrus maintaining their areas, with the remaining J. cedrus subsp. maderensis, suffering slight decrease of suitability in the lower areas of the Madeira Island. Significant contractions were observed for the remaining continental junipers. 

Finally, we discuss our results and findings considering the need to implement conservation measures to ensure the long-term survival of these species, and the importance of their forests in a growing dryer environment were they behave as pioneer species and foundational species.