Meta‐analysis of the differential effects of habitat fragmentation and degradation on plant genetic diversity

Abstract

Genetic diversity is a key factor for population survival and evolution. However, anthropogenic habitat disturbance can erode it, making populations more prone to extinction. Aiming to assess the global effects of habitat disturbance on plant genetic variation, we conducted a meta-analysis based on 92 case studies obtained from published literature. We compared the effects of habitat fragmentation and degradation on plant allelic richness and gene diversity (equivalent to expected heterozygosity) and tested whether such changes are sensitive to different life-forms, life spans, mating systems, and commonness. Anthropogenic disturbance had a negative effect on allelic richness, but not on gene diversity. Habitat fragmentation had a negative effect on genetic variation, whereas habitat degradation had no effect. When we examined the individual effects in fragmented habitats, allelic richness and gene diversity decreased, but this decrease was strongly dependent on certain plant traits. Specifically, common long-lived trees and self-incompatible species were more susceptible to allelic richness loss. Conversely, gene diversity decreased in common short-lived species (herbs) with self-compatible reproduction. In a wider geographical context, tropical plant communities were more sensitive to allelic richness loss, whereas temperate plant communities were more sensitive to gene diversity loss. Our synthesis showed complex responses to habitat disturbance among plant species. In many cases, the absence of effects could be the result of the time elapsed since the disturbance event or reproductive systems favoring self-pollination, but attention must be paid to those plant species that are more susceptible to losing genetic diversity, and appropriate conservation should be actions taken. Meta-Análisis de los Efectos Diferenciales de la Fragmentación y Degradación del Hábitat sobre la Diversidad Genética de las PlantasResumen: La diversidad genética es un factor clave para la supervivencia y evolución de las poblaciones. Sin embargo, la perturbación antropogénica de los hábitats puede dañar esta diversidad, volviendo a las poblaciones más susceptibles a la extinción. Con el objetivo de evaluar los efectos globales de la perturbación del hábitat sobre la variación genética de las plantas, realizamos un meta-análisis basado en 92 estudios de caso obtenidos de la literatura publicada. Comparamos los efectos de la degradación y fragmentación del hábitat sobre la riqueza de alelos y la diversidad de genes (equivalente a la heterocigosidad esperada) de las plantas y probamos si dichos cambios son sensibles para diferentes formas de vida, tiempos de vida, sistemas de apareamiento y preponderancia. La perturbación antropogénica tuvo un efecto negativo sobre la riqueza de alelos, pero no sobre la diversidad genética. La fragmentación del hábitat tuvo un efecto negativo sobre la variación genética, mientras que la degradación del hábitat no tuvo efecto. Cuando examinamos los efectos individuales en los hábitats fragmentados, Article...

Meta‐analysis of genetic representativeness of plant populations under ex situ conservation in contrast to wild source populations

“…We conducted subgroup meta-analysis to test whether genetic representativeness varied among different species characteristics, sampling strategies for ex situ conservation, and ex situ conservation types. Categories with <3 data points were excluded because of low reliability (González et al 2020).…”

“…These changes have led to an increased risk of extinction for wild plant populations (Pimm et al 2014). Indeed, local extirpation of wild plant populations and losses of local biodiversity are occurring across the world (Wiens 2016;González et al 2020). Because of these impacts, ex situ conservation strategies have become an essential approach to protecting wild plants and preventing total extinction (Havens et al 2006;Mounce et al 2017;Abeli et al 2020).…”

Life history, climate and biogeography interactively affect worldwide genetic diversity of plant and animal populations

“…This extinction debt, predominantly linked to woody species, has been of considerable concern to nature conservation, and indicates an underestimation of the number of long-living species endangered by habitat fragmentation 21,[82][83][84] . Although we did not specifically collect studies in the context of habitat fragmentation, land-use change and consequent fragmentation are among the most pronounced global change drivers across the earth, and have most likely affected most populations to some extent 85,86 .…”

Effect of Human Disturbance on Genetic Structure of Rare and EndangeredPaphiopedilum micranthumImplied the Habitat Status

“…The complex responses to habitat disturbance were closely related to the plants’ life-span, mating system and life-form. Long-lived trees and self-incompatible species were more susceptible to a changing habitat (Gonzalez et al., 2019).…”

“…(2017) found that population diversity parameters of Erigeron annuus did not significantly differ between stable habitats and disturbed regions. A recent meta-analysis based on 92 case studies revealed that anthropogenic disturbance had a negative effect on allelic richness, but not on genetic diversity (Gonzalez et al., 2019). Regarding the correlation between disturbance and genetic structure, some reported that the environmental disturbance variables at different scales were not associated with the spatial genetic structure or genetic divergence in palm populations (Soares et al., 2019).…”