TY - JOUR
T1 - Nutrient additions have direct and indirect effects on biocrust biomass in a long-term Chihuahuan Desert grassland experiment
AU - Baldarelli, Lauren M.
AU - Throop, Heather L.
AU - Collins, Scott L.
AU - Ward, David
N1 - Funding Information:
Many thanks to Christian Combs for field and laboratory assistance. We thank Stephanie Baker of the Sevilleta LTER for assistance with plant identification. We also thank Ben Specter for technical assistance and Art Link for chlorophyll a assistance. We also thank Drs. D. Bade, C. Blackwood, A. Case and X. Mou for use of laboratory equipment. This research was funded by the Herrick Trust , Kent State University .
Publisher Copyright:
© 2020
Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2021/1
Y1 - 2021/1
N2 - Anthropogenic activities have greatly affected some of the global biogeochemical cycles, including the nitrogen (N) and phosphorus (P) cycles. This alteration of nutrients has significantly impacted ecosystems around the globe. Arid ecosystems may be particularly vulnerable to changes in nutrient availability, in addition to their frequent limitation by water availability. We conducted a nutrient-fertilization experiment with an emphasis on the cover of biological soil crusts (biocrusts) in the Chihuahuan Desert. We manipulated N, P, and Potassium (K) in a full-factorial design. We visually estimated biocrust cover and fluorometrically measured chlorophyll a as an index of biocrust abundance. We found that there were significant interaction effects of N*P and N*K as well as significant main effects of N and P on chlorophyll a. Results from a path analysis suggest that both N and P had direct positive effects on aboveground vascular plant production and direct negative effects on chlorophyll a. There were also indirect negative effects on biocrust cover and chlorophyll a by vascular plant cover. Overall, nutrient additions had a direct positive effect on vascular plant cover, which in turn had a negative impact on biocrust cover. This indicates a possible mechanism for inter-taxon competition under conditions of increased nutrient availability.
AB - Anthropogenic activities have greatly affected some of the global biogeochemical cycles, including the nitrogen (N) and phosphorus (P) cycles. This alteration of nutrients has significantly impacted ecosystems around the globe. Arid ecosystems may be particularly vulnerable to changes in nutrient availability, in addition to their frequent limitation by water availability. We conducted a nutrient-fertilization experiment with an emphasis on the cover of biological soil crusts (biocrusts) in the Chihuahuan Desert. We manipulated N, P, and Potassium (K) in a full-factorial design. We visually estimated biocrust cover and fluorometrically measured chlorophyll a as an index of biocrust abundance. We found that there were significant interaction effects of N*P and N*K as well as significant main effects of N and P on chlorophyll a. Results from a path analysis suggest that both N and P had direct positive effects on aboveground vascular plant production and direct negative effects on chlorophyll a. There were also indirect negative effects on biocrust cover and chlorophyll a by vascular plant cover. Overall, nutrient additions had a direct positive effect on vascular plant cover, which in turn had a negative impact on biocrust cover. This indicates a possible mechanism for inter-taxon competition under conditions of increased nutrient availability.
KW - Biological soil crusts
KW - Inter-taxon competition
KW - Nutrient fertilization
KW - Nutrient network
KW - Path analysis
KW - Sevilleta long-term ecological research
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U2 - 10.1016/j.jaridenv.2020.104317
DO - 10.1016/j.jaridenv.2020.104317
M3 - Article
AN - SCOPUS:85091942462
SN - 0140-1963
VL - 184
JO - Journal of Arid Environments
JF - Journal of Arid Environments
M1 - 104317
ER -