Biogeochemical impacts of the northward expansion of kudzu under climate change: the importance of ecological context

Abstract

Abstract. Climate change is generally expected to push plant species to higher latitudes and elevations; how the climate-induced migrations of disruptive invasive species may affect higher-latitude ecosystems has not been widely examined. Kudzu (Pueraria montana) has large impacts on nitrogen (N) cycling and trace N gas emissions in the southeastern United States. To understand how its projected northward migration under climate change will impact ecosystems in the northeastern United States, we examine the impacts of kudzu in the Mid-Atlantic region, near kudzu's northern invasion front. We pair plots invaded by kudzu with adjacent uninvaded plots, and examine rates of leaf litter decomposition, soil nitrogen pools and net cycling rates, N trace gas emissions, and microbial dynamics. Kudzu litter has more N and decomposes faster than litter from co-occurring species. Unlike in Georgia, near the center of kudzu's current range in the United States, kudzu invasion in the Mid-Atlantic has very small ecosystem impacts, causing significant increases only in the sizes of soil nitrate pools. These Mid-Atlantic ecosystems may be buffered against invasion impacts, creating a lag between changes in the plant community and biogeochemical changes. A combination of factors, including time since establishment, soil types, growing season length, and temperatures, may limit kudzu's biogeochemical impacts along its invasion front.

Invasive species’ leaf traits and dissimilarity from natives shape their impact on nitrogen cycling: a meta‐analysis

“…Globalization has increased rates of invasion by exotic species (Sax et al ., ) and some have dramatic consequences for human and ecosystem health (Ehrenfeld, ; Steffen et al ., ). A critical way through which species invasions alter ecosystems is by increasing soil nitrogen (N) pools and fluxes (Ehrenfeld, ; Liao et al ., ; Vilà et al ., ; Pyšek et al ., ), speeding up N cycling in ways that can be harmful for people and ecosystems by reducing ecosystem nutrient retention, water quality, carbon storage, and increasing greenhouse gas emissions (Ehrenfeld, ; Hickman & Lerdau, ). Although these biogeochemical changes can be large (i.e.…”

Invasive perennial forb effects on gross soil nitrogen cycling and nitrous oxide fluxes depend on phenology

“…Most invasive plant studies measure only a few response variables, focusing on plant and soil properties such as biomass and nutrient pools rather than process rates (Hulme et al 2013). The few studies that have explored invasion effects on ecosystem N outputs show that invasion increases potential denitrification (Parker andSchimel 2010, Carey et al 2017) and gaseous N losses (Hickman and Lerdau 2013). Because we measured a suite of soil N pools and fluxes, we were able to link lower gross mineralization rates and smaller inorganic N pools to lower rates of gaseous N loss during a period of plant N uptake; we also measured enhancement of both microbial N-cycling activity and ecosystem N loss during a period of low plant N demand.…”

Cap. 7. Bosques. En: La Quinta Evaluación Nacional del Clima.

“…En Hawaii, el cambio climático y la propagación de gramíneas invasoras han aumentado la frecuencia y la extensión de los incendios forestales 32 . En el Sureste, el aumento de las temperaturas ha permitido que especies invasoras sensibles al frío, como el kudzu, se desplacen hacia el norte 33 , lo que afecta la estructura y la composición de los bosques. El kudzu y otras enredaderas leñosas se ven estimuladas por el aumento del dióxido de carbono (CO 2 ) 34 , y en algunos casos superan a los árboles y otras plantas 35 .…”