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Enhanced activity of soil nutrient-releasing enzymes after plant invasion: a meta-analysis. Zhou Yong,Staver A Carla Ecology Plant invasion can significantly alter soil nutrient cycling of ecosystems. How these changes are linked to soil enzyme activities is still unknown, however, even though these are proximate agents of organic matter decomposition and nutrient release. We performed a meta-analysis of 60 case studies examining responses of 10 unique soil enzymes to plant invasion, and tested whether invaded soils differed in their enzyme activities from uninvaded soils. We also examined whether increases in soil nutrient-releasing enzyme activity were paralleled by enhanced soil nutrient availability after plant invasion. Overall, we found that plant invasion had significant impacts on the activities of seven types of soil enzymes. Plant invasion had inconsistent impacts on C-decomposing enzymes, but invaded sites had significantly higher activities of soil enzymes related to N- and P-release than noninvaded sites. Increases in nutrient-releasing enzyme activity after plant invasion ranged from +23% to +69%, which potentially results in a linear increase of soil nutrient availability in response to enhanced enzyme activities. Invaded soils also had higher nutrient stocks and soil microbial biomass than uninvaded soils. Our results suggest that enhanced activity of soil nutrient-releasing enzymes after plant invasion may accelerate nutrient cycling, potentially creating a nutrient-rich soil environment that benefits invaders and promotes their persistence, as invasive plants often appear to be more resource-demanding and competitive than native species. 10.1002/ecy.2830
Fatness and fertility: which direction? Seminara Stephanie B The Journal of clinical investigation Metabolic status has long been thought to determine reproductive status, with abnormal metabolic phenotypes altering reproductive cascades, such as the onset of puberty. In this issue of the JCI, Tolson and colleagues provide evidence that kisspeptin, a hormone that promotes sexual maturation, regulates metabolism. Female mice lacking the kisspeptin receptor (KISS1R) gained more weight than control animals, and this weight gain was caused not by increased food consumption, but by an overall decrease in energy and metabolism. While this study provides a direct link between the kisspeptin pathway and metabolic output, more work will need to be done to determine whether alterations in this pathway contribute to human obesity. 10.1172/JCI76623
The role of mites in insect-fungus associations. Hofstetter R W,Moser J C Annual review of entomology The interactions among insects, mites, and fungi are diverse and complex but poorly understood in most cases. Associations among insects, mites, and fungi span an almost incomprehensible array of ecological interactions and evolutionary histories. Insects and mites often share habitats and resources and thus interact within communities. Many mites and insects rely on fungi for nutrients, and fungi benefit from them with regard to spore dispersal, habitat provision, or nutrient resources. Mites have important impacts on community dynamics, ecosystem processes, and biodiversity within many insect-fungus systems. Given that mites are understudied but highly abundant, they likely have bigger, more important, and more widespread impacts on communities than previously recognized. We describe mutualistic and antagonistic effects of mites on insect-fungus associations, explore the processes that underpin ecological and evolutionary patterns of these multipartite communities, review well-researched examples of the effects of mites on insect-fungus associations, and discuss approaches for studying mites within insect-fungus communities. 10.1146/annurev-ento-011613-162039