Spatial niche modelling of five endemic cacti from the Brazilian Caatinga: Past, present and future

Abstract

Climate change, together with human activities, impacts on natural and human systems on all continents and poses a major threat to biodiversity, especially in environments with a high rate of endemism and where species are profoundly adapted to specific environmental conditions, as is the case of the seasonally dry tropical forests, noticeably the Caatinga, an exclusively Brazilian biome. The objective of this study was to build spatial niche models of five species of Cactaceae (Arrojadoa penicillata, Brasilicereus phaeacanthus, Pereskia aureiflora, Stephanocereus leucostele and Tacinga inamoena) endemic to the Caatinga and with different traits, to evaluate the impact of climate change on their geographical distribution. The species records and environmental variable values were overlaid on a grid of 6818 cells with 0.5° spatial resolution. Niche models were obtained for five types of general circulation models between ocean and atmosphere and 12 different ecological models. The ensemble ecological niche model was calculated at present and projected to past (last glacial maximum – LGM, 21 000; and mid‐Holocene – Hol, 6000 years ago) and future climate conditions (average of 2080), under the effect of climate change, in the greenhouse gas emission scenario RCP4.5. The distribution pattern of the studied species indicates an area with less environmental suitability in the LGM, followed by an expansion that began in the Hol and continued until the present period. In the future (2080), the models predicted a retraction of areas of environmental suitability, in which P. aureiflora and B. phaeacanthus, given their more restricted, marginal habitat and woody habit, present a great risk of extinction, whilst S. leucostele, A. penicillata and T. inamoena present a smaller reduction in suitable area, partly reflecting their spreading, less woody habit. Regional conservation actions for Cactaceae species and their habitat need to take these findings into account if we are to ensure the survival of these species.

Análise populacional de Tacinga inamoena (K. Schum.) N. P. Taylor & Stuppy numa Caatinga Hiperxerófila

“…De acordo com esses autores, fatores como disponibilidade de recursos, condições edafoclimáticas, perturbações antrópicas ou naturais, interferem na estrutura e dinâmica vegetal e, consequentemente, as populações de C. jamacaru. Estudos recentes têm apontado os impactos das mudanças climáticas e o uso forrageiro como os principais fatores que afetam a distribuição de cactáceas endêmicas da Caatinga e, a médio e longo prazo, algumas espécies apresentarão grande risco de extinção, enquanto que outras apresentarão uma queda na distribuição em seus habitats (Simões et al, 2019;Carvalho, 2016). Assim, estudos como este com Cactaceae que ocorrem na Caatinga são incentivados para entender o estabelecimento e as chances de sobrevivência dessas espécies no seu ambiente natural, sobretudo, diante de um cenário de mudanças climáticas e intervenções antrópicas.…”

“…As mudanças climáticas, juntamente com as atividades humanas, impactam os ecossistemas naturais em todos os continentes e representam uma grande ameaça à biodiversidade, especialmente em ambientes com alto índice de endemismo e onde as espécies são profundamente adaptadas às condições ambientais específicas, como é o caso das florestas tropicais sazonalmente secas, notavelmente a Caatinga, um bioma exclusivamente brasileiro (Simões et al, 2019). As condições edafoclimáticas da Caatinga favorecem o desenvolvimento de espécies vegetais bem adaptadas à região (Souza et al, 2019), a exemplo das cactáceas, que apresentam características adaptativas singulares em áreas com déficit hídrico e elevada amplitude térmica.…”

Multi-temporal ecological niche modeling for bird conservation in the face of climate change scenarios in Caatinga, Brazil

“… Silva et al (2019) showed that, throughout the Caatinga biome, areas of suitable habitat for endemic plant species would be reduced under both optimistic and pessimistic future climate change scenarios. Simoes et al (2019) found that endemic cacti species are threatened with extinction due to the retraction of environmentally suitable areas. This area reduction for plants in STDFs was also reported in other works ( Oyama & Nobre, 2003 ; De Andrade et al, 2017 , Marengo, Torres & Alves, 2017 ).…”

“…Furthermore, this region is home to sites of interest for establishing new areas of integral protection due to extensive natural remnants ( MMA, 2021 ; Antongiovanni, Venticinque & Fonseca, 2018 ; Antongiovanni et al, 2020 ). The south of the Caatinga is fundamental for the conservation of cacti species ( Carvalho et al, 2022 ) and one of the few areas in eastern Brazil capable of safeguarding different Cactaceae species in climate change scenarios in the next 60 years ( Simoes et al, 2019 ). The east and central parts are also crucial for conserving endemic plants from the Caatinga dry forest ( Silva et al, 2019 ), corroborating the pattern found in the present study.…”

The fate of Holoregmia, a monospecific genus endemic to the Brazilian Caatinga, under different future climate scenarios

“…If the climate changes permanently, this will affect the ecological niche of species in this environment (e.g. Chagas et al 2020;Silva et al 2020;Simões et al 2020).…”