A 10‐year decrease in plant species richness on a neotropical inselberg: detrimental effects of global warming?

Abstract

International audienceThe census of vascular plants across a 10-year interval (1995-2005) at the fringe of a neotropical rainforest (Nouragues inselberg, French Guiana, South America) revealed that species richness decreased, both at quadrat scale (2 m2) and at the scale of the inselberg (three transects, embracing the whole variation in community composition). Juvenile stages of all tree and shrub species were most severely affected, without any discrimination between life and growth forms, fruit and dispersion types, or seed sizes. Species turnover in time resulted in a net loss of biodiversity, which was inversely related to species occurrence. The most probable cause of the observed species disappearance is global warming, which severely affected northern South America during the last 50 years (+2° C), with a concomitant increase in the occurrence of aridity

Stability of plant communities along a tropical inselberg ecotone in French Guiana (South America)

“…It may even be thought that present-day climate warming, and accompanying increased frequency of severe El Niño events in the Southern Oscillation Zone (Malhi and Wright, 2004) cause a reversion of the successional progress. Results of a parallel study showed that the recruitment of juveniles of woody species between 1995 and 2005 was severely affected by the severe El-Niño event which occurred in 1997 (Fonty et al, 2009). In this study we observed a decrease of 24% for individuals and 22% for species over the 205 quadrats of the three transects (totalling 410 m 2 ).…”

“…In a previous paper, we reported a marked decrease in plant species richness and tree recruitment in a 10-yr period (1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005) embracing a severe El-Niño event in 1997 (Fonty et al, 2009). In the present study, we explored the community scale and questioned the temporal change of the vegetation on the ecotone gradient over the same period.…”

“…Mean annual air temperature lies between 25 and 27 • C at the Nouragues station (Grimaldi and Riéra, 2001). Climatic measurements (synthesis in Fonty et al, 2009) indicate a marked El Niño event in 1997. This granitic whaleback dome protruding ∼300 m from the rain forest matrix (Fig.…”

The impact of red howler monkey latrines on the distribution of main nutrients and on topsoil profiles in a tropical rain forest

“…In the understorey of the tall-tree rain forest, the air temperature varies from 24.9°C to 28.5°C and the air humidity varies from 84.4% to 96.7% (FF, personal data, 2008). More detailed climate data, including present-day warming trends, are available in Fonty et al (2009). Soils are acid (pH < 5) claysandy Ferralsols (FAO 2006) with a micro-aggregate texture of biological origin and a sparsely distributed litter cover (Grimaldi & Riéra 2001).…”

Variations in dung beetles assemblages (Coleoptera: Scarabaeidae) within two rain forest habitats in French Guiana

“…We need replicates on a larger scale and to investigate other natural habitat types such as riverine lowland cloud forest (obregon et al 2011), bamboo forest or palm swamp to understand the effects of natural forest dynamics and by extension of anthropogenic disturbance on species distribution. A regular increase in temperature observed over the last 50 years in French Guiana was the most probable cause of plant species richness 10-year decrease in low forest in Nouragues (Fonty et al 2009). Similar trends are predicted in several region of South America (Boulanger et al 2006) which may play direct or indirect role on dung beetle communities through changes in forest structure.…”