Hydraulic tradeoffs underlie local variation in tropical forest functional diversity and sensitivity to drought

Abstract Background and Aims In fragmented forests, proximity to forest edges can favour the establishment of resource-acquisitive species over more resource-conservative species. During seedling recruitment, resource-acquisitive species may benefit from either higher light availability or weaker top-down effects of natural enemies. The relative importance of light and enemies for recruitment has seldom been examined with respect to edge effects. Methods In a human-modified wet tropical forest in India, we first examined how functional traits indicative of resource-acquisitive vs. resource-conservative strategies, i.e. specific leaf area (SLA), leaf dry matter content, wood density and seed size, explained interspecific differences in densities of seedling recruits with distance to the forest edge. Then, we checked whether fungicide and insecticide treatments and canopy openness (proxy for light availability) explained edge effects on trait-mediated changes in seedling density. Finally, we examined whether light availability and natural enemy activity explained edge effects on functional diversity of seedling recruits. Key Results Up to 60 m from edges, recruit densities increased with decreasing seed size, but not at 90–100 m, where recruit densities increased with higher SLA. Trait-mediated variation in recruit densities changed with pesticides only at 90–100 m: compared with control plots, fungicide increased recruit densities for low SLA species and insecticide increased smaller seeded species. For SLA, wood density and seed size, functional diversity of recruits was higher at 90–100 m than at 0–5 m. At 90–100 m, fungicide decreased functional diversity for SLA and insecticide reduced seed size diversity compared with control plots. Canopy openness explained neither variation in recruit density in relation to traits nor functional diversity. Conclusions Altered biotic interactions can mediate local changes to trait composition and functional diversity during seedling recruitment in forest fragments, hinting at downstream effects on the structure and function of human-modified forests.

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Variation in hydroclimate sustains tropical forest biomass and promotes functional diversity

New Phytologist ◽

10.1111/nph.15271 ◽

2018 ◽

Vol 219 (3) ◽

pp. 932-946 ◽

Cited By ~ 13

Author(s):

Thomas L. Powell ◽

Charles D. Koven ◽

Daniel J. Johnson ◽

Boris Faybishenko ◽

Rosie A. Fisher ◽

...

Keyword(s):

Tropical Forest ◽

Functional Diversity ◽

Forest Biomass

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The sperm-associated microbiota of crickets and their local variation and rapid turnover

10.1101/2021.10.10.463754 ◽

2021 ◽

Author(s):

Barbara Angela Eckel ◽

Anastasia Victoria Illner ◽

Oliver Otti ◽

Klaus Reinhardt

Keyword(s):

Functional Diversity ◽

Potential Role ◽

Local Variation ◽

Rapid Turnover ◽

Male Sperm ◽

Different Populations ◽

Sperm Population

While studying aspects of the sperm biology and immunity of two species of crickets, we encountered bacteria that were released from the male sperm container, the spermatophore, alongside sperm. We describe a presumably rich microbe flora in the sperm population ('sperm-associated microbiota'). These sperm-associated microbiota differed between the two species of cricket and between different populations and showed functional diversity. Further, sperm-associated microbiota killed sperm, highlighting their potential role in fitness, especially since they are most likely transferred to females during mating.

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Tropical mammal functional diversity increases with productivity but decreases with anthropogenic disturbance

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2020.2098 ◽

2021 ◽

Vol 288 (1945) ◽

pp. 20202098

Author(s):

Daniel Gorczynski ◽

Chia Hsieh ◽

Jadelys Tonos Luciano ◽

Jorge Ahumada ◽

Santiago Espinosa ◽

...

Keyword(s):

Tropical Forest ◽

Observational Data ◽

Functional Diversity ◽

Primary Productivity ◽

Positive Association ◽

Camera Trap ◽

Tropical Regions ◽

Functional Richness ◽

Functional Dispersion ◽

Mammal Communities

A variety of factors can affect the biodiversity of tropical mammal communities, but their relative importance and directionality remain uncertain. Previous global investigations of mammal functional diversity have relied on range maps instead of observational data to determine community composition. We test the effects of species pools, habitat heterogeneity, primary productivity and human disturbance on the functional diversity (dispersion and richness) of mammal communities using the largest standardized tropical forest camera trap monitoring system, the Tropical Ecology Assessment and Monitoring (TEAM) Network. We use occupancy values derived from the camera trap data to calculate occupancy-weighted functional diversity and use Bayesian generalized linear regression to determine the effects of multiple predictors. Mammal community functional dispersion increased with primary productivity, while functional richness decreased with human-induced local extinctions and was significantly lower in Madagascar than other tropical regions. The significant positive relationship between functional dispersion and productivity was evident only when functional dispersion was weighted by species' occupancies. Thus, observational data from standardized monitoring can reveal the drivers of mammal communities in ways that are not readily apparent from range map-based studies. The positive association between occupancy-weighted functional dispersion of tropical forest mammal communities and primary productivity suggests that unique functional traits may be more beneficial in more productive ecosystems and may allow species to persist at higher abundances.

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