01980nas a2200133 4500008004100000245011500041210007100156300001000227490000800237520150500245100002101750700001801771856005701789 2023 eng d00aElectrolytes on the prairie: How urine‐like additions of Na and K shape the dynamics of a grassland food web0 aElectrolytes on the prairie How urine‐like additions of Na and K ae38560 v1043 a

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.

1 aKaspari, Michael1 aWelti, E.A.R. uhttps://onlinelibrary.wiley.com/doi/10.1002/ecy.385601392nas a2200133 4500008004100000245010600041210006900147490000700216520091600223100002101139700001401160700001801174856006601192 2022 eng d00aHow and why grasshopper community maturation rates are slowing on a North American tall grass prairie0 aHow and why grasshopper community maturation rates are slowing o0 v183 a

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.

1 aKaspari, Michael1 aJoern, A.1 aWelti, E.A.R. uhttps://royalsocietypublishing.org/doi/10.1098/rsbl.2021.051000507nas a2200133 4500008004100000245011300041210006900154300001100223490000800234100002100242700002300263700001800286856006900304 2021 eng d00aHow and why plant ionomes vary across North American grasslands and its implications for herbivore abundance0 aHow and why plant ionomes vary across North American grasslands  ae034590 v1021 aKaspari, Michael1 aBeurs, Kirsten, M.1 aWelti, E.A.R. uhttps://esajournals.onlinelibrary.wiley.com/doi/10.1002/ecy.345902168nas a2200133 4500008004100000245008600041210006900127300001400196490000700210520169700217100001801914700002101932856008101953 2021 eng d00aSodium addition increases leaf herbivory and fungal damage across four grasslands0 aSodium addition increases leaf herbivory and fungal damage acros a1212-12210 v353 a

    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.

1 aWelti, E.A.R.1 aKaspari, Michael uhttps://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2435.13796?af=R00677nas a2200193 4500008004100000245013200041210006900173300001400242490000600256100001800262700001400280700002300294700002500317700001800342700002500360700002300385700002100408856005400429 2021 eng d00aStudies of insect temporal trends must account for the complex sampling histories inherent to many long-term monitoring efforts0 aStudies of insect temporal trends must account for the complex s a589–5910 v51 aWelti, E.A.R.1 aJoern, A.1 aEllison, Aaron, M.1 aLightfoot, David, C.1 aRecord, Sydne1 aRodenhouse, Nicholas1 aStanley, Emily, H.1 aKaspari, Michael uhttp://www.nature.com/articles/s41559-021-01424-0