Agricultural landscape heterogeneity matter: responses of neutral genetic diversity and adaptive traits in a neotropical savanna tree
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2020
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Plants are one of the most vulnerable groups to fragmentation and habitat loss, that may
affect community richness, abundance, functional traits, and genetic diversity. Here, we
address the effects of landscape features on adaptive quantitative traits and evolutionary
potential, and on neutral genetic diversity in populations of the Neotropical savanna
tree Caryocar brasiliense. We sampled adults and juveniles in 10 savanna remnants
within five landscapes. To obtain neutral genetic variation, we genotyped all individuals
from each site using nine microsatellite loci. For adaptive traits we measured seed size
and mass and grown seeds in nursery in completely randomized experimental design.
We obtained mean, additive genetic variance (Va) and coefficient of variation (CVa%),
which measures evolvability, for 17 traits in seedlings. We found that landscapes with
higher compositional heterogeneity (SHDI) had lower evolutionary potential (CVa%) in
leaf length (LL) and lower aboveground dry mass (ADM) genetic differentiation (QST ).
We also found that landscapes with higher SHDI had higher genetic diversity (He) and
allelic richness (AR) in adults, and lower genetic differentiation (FST ). In juveniles, SHDI
was also positively related to AR. These results are most likely due to longer dispersal
distance of pollen in landscapes with lower density of flowering individuals. Agricultural
landscapes with low quality mosaic may be more stressful for plant species, due to the
lower habitat cover (%), higher cover of monocropping (%) and other land covers, and
edge effects. However, in landscapes with higher SHDI with high quality mosaic, forest
nearby savanna habitat and the other environments may facilitate the movement or
provide additional habitat and resources for seed disperses and pollinators, increasing
gene flow and genetic diversity. Finally, despite the very recent agriculture expansion in
Central Brazil, we found no time lag in response to habitat loss, because both adults
and juveniles were affected by landscape changes.
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Agroecosystem, Qquantitative genetics, Caryocaraceae, Aandscape genetics, Cerrado, Fragmentation, Model selection, Genetic diversity
Citação
AMARAL, Tatiana Souza do; SANTOS, Juliana Silveira dos ; ROSA, Fernanda Fraga; PESSÔA, Marcelo Bruno; CHAVES, Lázaro José; RIBEIRO, Milton Cezar; COLLEVATTI, Rosane Garcia. Agricultural landscape heterogeneity matter: responses of neutral genetic diversity and adaptive traits in a neotropical savanna tree. Frontiers in Genetics, Laussane, v. 11, p. 606222, 2021. DOI: 10.3389/fgene.2020.606222. Disponível em: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7890196/pdf/fgene-11-606222.pdf. Acesso em: 9 mar. 2023.