Nutrient additions have direct and indirect effects on biocrust biomass in a long-term Chihuahuan Desert grassland experiment

被引：15

作者：

Baldarelli, Lauren M. ^{[1
]}

Throop, Heather L. ^{[2
,3
]}

Collins, Scott L. ^{[4
]}

Ward, David ^{[1
]}

机构：

[1] Kent State Univ, Dept Biol Sci, Kent, OH 44242 USA

[2] Arizona State Univ, Sch Earth & Space Explorat, Tempe, AZ 85287 USA

[3] Arizona State Univ, Sch Life Sci, Tempe, AZ 85287 USA

[4] Univ New Mexico, Dept Biol, Albuquerque, NM 87131 USA

来源：

JOURNAL OF ARID ENVIRONMENTS | 2021年 / 184卷

关键词：

Biological soil crusts; Sevilleta long-term ecological research; Nutrient fertilization; Nutrient network; Inter-taxon competition; Path analysis; BIOLOGICAL SOIL CRUSTS; BIOGEOCHEMICAL CYCLES; MULTIMODEL INFERENCE; BEHAVIORAL ECOLOGY; MODEL SELECTION; NITROGEN; DEPOSITION; RESPIRATION; LIMITATION; RESPONSES;

D O I：

10.1016/j.jaridenv.2020.104317

中图分类号：

Q14 [生态学（生物生态学）];

学科分类号：

071012 ; 0713 ;

摘要：

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.

引用

页数：7