This dataset contains data and analysis code for the paper entitled
“Acclimation of the nitrogen cycle to changes in precipitation"
by Currier et al. As the frequency of precipitation extremes are
expected to increase, especially in arid regions, we asked how
prolonged shifts in water availability facilitate acclimation of the
N cycle in a semiarid grassland. Using natural abundances of stable
nitrogen isotopes for dominant plants and soils and rainfall
manipulation experiments, we tested the hypothesis that N cycling
will interact with water availability further amplifying the
openness of the N cycle through time. For the dominant plant
species, we found the relationship for N availability vs. ambient
annual precipitation to be significantly positive, contrary to
global spatial models. We also considered the temporal dynamics of
our experiments, which imposed directional rainfall manipulations in
duration ranging from 5 to 14 years. The slopes of these
relationships decreased (became less positive) with more time since
the onset of the directional precipitation extremes. These data and
metadata supplement long-term foliar and soil isotope data from the
Jornada LTER (Dataset ID: knb-lter-jrn.210586001) with a large
spatial dataset from NEON data package DP1.10026.001 and Craine et
al. 2018 (https://doi.org/10.5061/dryad.v2k2607).
more »
« less
Water availability modifies productivity response to biodiversity and nitrogen in long‐term grassland experiments
Diversity and nitrogen addition have positive relationships with plant productivity, yet climate‐induced changes in water availability threaten to upend these established relationships. Using long‐term data from three experiments in a mesic grassland (ranging from 17 to 34 yr of data), we tested how the effects of species richness and nitrogen addition on community‐level plant productivity changed as a function of annual fluctuations in water availability using growing season precipitation and the Standardized Precipitation‐Evapotranspiration Index (SPEI). While results varied across experiments, our findings demonstrate that water availability can magnify the positive effects of both biodiversity and nitrogen addition on productivity. These results suggest that productivity responses to anthropogenic species diversity loss and increasing nitrogen deposition could depend on precipitation regimes, highlighting the importance of testing interactions between multiple global change drivers.
more » « less- NSF-PAR ID:
- 10362539
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Ecological Applications
- Volume:
- 31
- Issue:
- 6
- ISSN:
- 1051-0761
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
more » « less
Abstract Questions Predicted increases in temperature and changes to precipitation are expected to alter the amount of plant available nutrients, in turn, altering rates of primary production and exotic plant invasions. However, it remains unclear whether increased responses occur in wetter than average years, even in low fertility and low rainfall regions.
Location Four Australian grasslands, including sites in arid Western Australia, semi‐arid Victoria, alpine Victoria and sub‐tropical Queensland.
Methods Using identical nutrient addition experiments, we use 6‐years of biomass, cover and species richness data to examine how rates of biomass production and native and exotic cover and richness are affected by growing season precipitation [proportion of yearly growing season precipitation (
GSP ) to long‐term meanGSP ] and nutrient (N, P, K and micronutrients) addition.Results Rates of grassland productivity strongly increased with increasing
GSP .GSP increased rates of native cover but not native or exotic richness, nor rates of exotic cover change. We detected no significantNPK effect on rates of grassland productivity, exotic cover or exotic richness change. In contrast,NPK addition decreased rates of native cover change and fertilized plots had significantly fewer native species. We did not detect a significant interaction betweenNPK andGSP .Conclusions Grassland productivity was more strongly predicted by variation in growing season precipitation than by nutrient addition, suggesting it will vary with future changes in rainfall. Response to nutrients, however, depend on species origin, suggesting that increasing soil nutrient availability due to anthropogenic activities is likely to lead to negative effects on native species richness and cover.
-
more » « less
Abstract Although diversity‐dependent plant–soil feedbacks (PSFs) may contribute significantly to plant diversity effects on ecosystem functioning, the influences of underlying abiotic and biotic mechanistic pathways have been little explored to date. Here, we assessed such pathways with a PSF experiment using soil conditioned for ≥12 yr from two grassland biodiversity experiments. Model plant communities differing in plant species and functional group richness (current plant diversity treatment) were grown in soils conditioned by plant communities with either low‐ or high‐diversity (soil history treatment). Our results indicate that plant diversity can modify plant productivity through both diversity‐mediated plant–plant and plant–soil interactions, with the main driver (current plant diversity or soil history) differing with experimental context. Structural equation modeling suggests that the underlying mechanisms of PSFs were explained to a significant extent by both abiotic and biotic pathways (specifically, soil nitrogen availability and soil nematode richness). Thus, effects of plant diversity loss on plant productivity may persist or even increase over time because of biotic and abiotic soil legacy effects.
-
more » « less
Abstract In most plant communities, the net effect of nitrogen enrichment is an increase in plant productivity. However, nitrogen enrichment also has been shown to decrease species richness and to acidify soils, each of which may diminish the long‐term impact of nutrient enrichment on productivity. Here we use a long‐term (20 year) grassland plant diversity by nitrogen enrichment experiment in Minnesota, United States (a subexperiment within the BioCON experiment) to quantify the net impacts of nitrogen enrichment on productivity, including its potential indirect effects on productivity via changes in species richness and soil pH over an experimental diversity gradient. Overall, we found that nitrogen enrichment led to an immediate positive increment in productivity, but that this effect became nonsignificant over later years of the experiment, with the difference in productivity between fertilized and unfertilized plots decreasing in proportion to nitrogen addition‐dependent declines in soil pH and losses of plant diversity. The net effect of nitrogen enrichment on productivity could have been 14.5% more on average over 20 years in monocultures if not for nitrogen‐induced decreases in pH and about 28.5% more on average over 20 years in 16 species communities if not for nitrogen‐induced species richness losses. Together, these results suggest that the positive effects of nutrient enrichment on biomass production can diminish in their magnitude over time, especially because of soil acidification in low diversity communities and especially because of plant diversity loss in initially high diversity communities.
-
more » « less
Abstract Effects of plant diversity on grassland productivity, or overyielding, are found to be robust to nutrient enrichment. However, the impact of cumulative nitrogen (N) addition (total N added over time) on overyielding and its drivers are underexplored. Synthesizing data from 15 multi-year grassland biodiversity experiments with N addition, we found that N addition decreases complementarity effects and increases selection effects proportionately, resulting in no overall change in overyielding regardless of N addition rate. However, we observed a convex relationship between overyielding and cumulative N addition, driven by a shift from complementarity to selection effects. This shift suggests diminishing positive interactions and an increasing contribution of a few dominant species with increasing N accumulation. Recognizing the importance of cumulative N addition is vital for understanding its impacts on grassland overyielding, contributing essential insights for biodiversity conservation and ecosystem resilience in the face of increasing N deposition.
