@article {6106, title = {Electrolytes on the prairie: How urine-like additions of Na and K shape the dynamics of a grassland food web}, journal = {Ecology}, volume = {104}, year = {2023}, pages = {e3856}, abstract = {

The electrolytes Na and K both function to maintain water balance and membrane potential. However, these elements work differently in plants\—where K is the primary electrolyte\—than in animals\—where ATPases require a balanced supply of Na and K. Here we use monthly factorial additions of Na and K to simulate bovine urine inputs and explore how these electrolytes ramify through a prairie food web. Against a seasonal trend of increasing grass biomass and decreasing water and elemental tissue concentrations, +K and +Na plots boosted water content and, when added together, plant biomass. Compared to control plots, +Na and +K plots increased element concentrations in aboveground plant tissue early in summer and decreased them in September. Simultaneously, invertebrate abundance on Na and K additions were sequentially higher and lower than control plots from June-September and were most suppressed when grass was most nutrient rich. K was the more effective plant electrolyte, but Na frequently promoted similar changes in grass ionomes. The soluble/leachable ions of Na and K showed significant ability to shape plant growth, water content, and the 15-element ionome, with consequences for higher trophic levels. Grasslands with high inputs of Na and K\—via large mammal grazers or coastal aerosol deposition\—likely enhance the ability of plants to adjust their aboveground ionomes, with dramatic consequences for the distribution of invertebrate consumers.

}, keywords = {LTER-KNZ}, doi = {10.1002/ecy.3856}, url = {https://onlinelibrary.wiley.com/doi/10.1002/ecy.3856}, author = {Kaspari, Michael and Welti, E.A.R.} } @article {6027, title = {How and why grasshopper community maturation rates are slowing on a North American tall grass prairie}, journal = {Biology Letters}, volume = {18}, year = {2022}, abstract = {

Invertebrate growth rates have been changing in the Anthropocene. We examine rates of seasonal maturation in a grasshopper community that has been declining annually greater than 2\% a year over 34 years. As this grassland has experienced a 1\°C increase in temperature, higher plant biomass and lower nutrient densities, the community is maturing more slowly. Community maturation had a nutritional component: declining in years/watersheds with lower plant nitrogen. The effects of fire frequency were consistent with effects of plant nitrogen. Principal components analysis also suggests associated changes in species composition\—declines in the densities of grass feeders were associated with declines in community maturation rates. We conclude that slowed maturation rates\—a trend counteracted by frequent burning\—likely contribute to long-term decline of this dominant herbivore.

}, keywords = {LTER-KNZ}, doi = {10.1098/rsbl.2021.0510}, url = {https://royalsocietypublishing.org/doi/10.1098/rsbl.2021.0510}, author = {Kaspari, Michael and A. Joern and Welti, E.A.R.} } @article {6120, title = {How and why plant ionomes vary across North American grasslands and its implications for herbivore abundance}, journal = {Ecology}, volume = {102}, year = {2021}, pages = {e03459}, keywords = {LTER-KNZ}, doi = {10.1002/ecy.3459}, url = {https://esajournals.onlinelibrary.wiley.com/doi/10.1002/ecy.3459}, author = {Kaspari, Michael and Beurs, Kirsten M. and Welti, E.A.R.} } @article {KNZ002056, title = {Sodium addition increases leaf herbivory and fungal damage across four grasslands}, journal = {Functional Ecology}, volume = {35}, year = {2021}, pages = {1212-1221}, abstract = {

\ \ \  1. Sodium (Na) is an essential element for all animals, but not plants. Soil Na supplies vary geographically. Animals that primarily consume plants thus have the potential to be Na limited and plants that uptake Na may be subject to higher rates of herbivory, but their high Na content also may attract beneficial partners such as pollinators and seed dispersers.
\ \ \  2. To test for the effects of Na biogeochemistry on herbivory, we conducted distributed Na press experiments (monthly Na application across the growing season) in four North American grasslands.
\ \ \  3. Na addition increased soil and plant Na concentrations at all sites. Grasses in Na addition plots had significantly higher herbivore damage by leaf miners and fungal pathogens than those in control plots. Forbs with higher foliar Na concentrations had significantly more chewing insect herbivore and fungal damage.
\ \ \  4. While no pattern was evident across all species, several forb species had higher Na concentrations in inflorescences compared to leaves, suggesting they may allocate Na to attract beneficial partners.
\ \ \  5. The uptake of sodium by plants, and animal responses, has implications for the salinification in the Anthropocene. Increased use of road salt, irrigation with saline groundwater, rising sea levels, and increasing temperatures and evapotranspiration rates with climate change can all increase inputs of sodium into terrestrial ecosystems.
\ \ \  6. Our results suggest increasing terrestrial sodium availability will benefit insect herbivores and plant fungal pathogens.

}, keywords = {LTER-KNZ}, doi = {10.1111/1365-2435.13796}, url = {https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2435.13796?af=R}, author = {Welti, E.A.R. and Kaspari, Michael} } @article {KNZ002057, title = {Studies of insect temporal trends must account for the complex sampling histories inherent to many long-term monitoring efforts}, journal = {Nature Ecology \& Evolution}, volume = {5}, year = {2021}, pages = {589{\textendash}591}, keywords = {LTER-KNZ}, doi = {10.1038/s41559-021-01424-0}, url = {http://www.nature.com/articles/s41559-021-01424-0}, author = {Welti, E.A.R. and A. Joern and Ellison, Aaron M. and Lightfoot, David C. and Record, Sydne and Rodenhouse, Nicholas and Stanley, Emily H. and Kaspari, Michael} }