Bioturbation by mammals and fire interact to alter ecosystem-level nutrient dynamics in longleaf pine forests

Activities of ecosystem engineers can interact with other disturbances to modulate rates of key processes such as productivity and nutrient cycling. Bioturbation, movement of soil by organisms, is a widespread form of ecosystem engineering in terrestrial ecosystems. We propose that bioturbation by s...

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Bibliographic Details
Published in:PloS one 2018-08, Vol.13 (8), p.e0201137-e0201137
Main Authors: Clark, Kenneth L, Branch, Lyn C, Farrington, Jennifer
Format: Article
Language:English
Subjects:
Animals
Biology and Life Sciences
Bioturbation
Coniferous forests
Consumption
Decomposition
Ecological Parameter Monitoring - methods
Ecology
Ecology and Environmental Sciences
Ecosystem
Ecosystem assessment
Engineers
Fires
Forest & brush fires
Forest ecosystems
Forest floor
Forests
Geomyidae
Gophers
Litter
Mammals
Mounds
Nitrogen
Nitrogen - chemistry
Nutrient cycles
Nutrient dynamics
Nutrients
Nutrients in soil
Nutritive Value
Phosphorus
Phosphorus - chemistry
Pine
Pine trees
Pinus
Pinus palustris
Plant Leaves - chemistry
Prairies
Prescribed fire
Productivity
Quercus laevis
Soil - chemistry
Soil nutrients
Terrestrial ecosystems
Terrestrial environments
Trees
Volatilization
Wildlife conservation
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Summary:Activities of ecosystem engineers can interact with other disturbances to modulate rates of key processes such as productivity and nutrient cycling. Bioturbation, movement of soil by organisms, is a widespread form of ecosystem engineering in terrestrial ecosystems. We propose that bioturbation by southeastern pocket gophers (Geomys pinetis), an abundant but declining ecosystem engineer in longleaf pine (Pinus palustris Mill.) forests, accelerates nutrient dynamics of the forest floor by burying litter and then reduces litter consumption and nitrogen (N) volatilization losses in the presence of fire. We evaluated our hypothesis by measuring how litter burial alters decomposition and N and phosphorus (P) turnover of longleaf pine and turkey oak (Quercus laevis Walt.) litter over four years, and then simulated interactive ecosystem-level effects of litter burial and low-intensity fires on N and P dynamics of the litter layer. In the field, mass loss was over two times greater and N and P were released much more rapidly from litter buried beneath mounds than on the surface of the forest floor. At a measured rate of mound formation covering 2.3 ± 0.6% of the forest floor per year, litter mass and N and P content of the forest floor simulated over an eight-year period were approximately 11% less than amounts in areas without pocket gopher mounds. In contrast to unburied litter, litter beneath mounds is protected from consumption during fires, and as fire interval increased, consumption rates decreased because mounds cover more years of accumulated litter. Our research indicates that bioturbation and burial of litter by pocket gophers accelerates turnover of N and P on the forest floor, and in the presence of fire, conserves N in this ecosystem where productivity is known to be nutrient limited.
ISSN:1932-6203
1932-6203
DOI:10.1371/journal.pone.0201137