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Biomantling and bioturbation by colonies of the Florida harvester ant, Pogonomyrmex badius.

Tschinkel WR - PLoS ONE (2015)

Bottom Line: These parameters were used in a simulation to estimate the amount of soil mantled over time by the observed population of P. badius colonies.Spread evenly, P. badius mantling would create a soil layer averaging 0.43 cm thick in a millennium, with 10-15% of the soil deriving from depths greater than 1 m.Biomantling by P. badius is discussed in the context of the ant community of which it is a part, and in relation to literature reports of ant biomantling.

View Article: PubMed Central - PubMed

Affiliation: Dept. of Biological Science, Florida State University, Tallahassee, Florida, United States of America.

ABSTRACT
In much of the world, soil-nesting ants are among the leading agents of biomantling and bioturbation, depositing excavated soil on the surface or in underground chambers. Colonies of the Florida harvester ant, Pogonomyrmex badius excavate a new nest once a year on average, depositing 0.1 to 12 L (3 L average) of soil on the surface. Repeated surveys of a population of about 400 colonies yielded the frequency of moves (approximately once per year), the distance moved (mean 4 m), and the direction moved (random). The area of the soil disc correlated well with the volume and maximum depth of the nest, as determined by excavation and mapping of chambers. The population-wide frequency distribution of disc areas thus yielded the frequency distribution of nest volumes and maximum depths. For each surveyed colony, the volume of soil excavated from six specified depth ranges and deposited on the surface was estimated. These parameters were used in a simulation to estimate the amount of soil mantled over time by the observed population of P. badius colonies. Spread evenly, P. badius mantling would create a soil layer averaging 0.43 cm thick in a millennium, with 10-15% of the soil deriving from depths greater than 1 m. Biomantling by P. badius is discussed in the context of the ant community of which it is a part, and in relation to literature reports of ant biomantling.

No MeSH data available.


Mean size-free distribution of chamber area by decile of maximum depth.Data from Tschinkel [31].
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pone.0120407.g004: Mean size-free distribution of chamber area by decile of maximum depth.Data from Tschinkel [31].

Mentions: These distributions, volumes and frequencies produce the overall rates of biomantling. What remains to be estimated is the relative amount of soil brought up from various depths. To this end, Tschinkel [31] showed that the "size-free shape" of the nest does not change with nest size (i.e. the proportion of total nest area (volume) found at each proportion of maximum depth is invariant) (Fig. 4). Therefore, given a total nest volume derived from the disc area, the distribution of this volume in relation to depth can be estimated from the relationship in Fig. 4. For the simulations, the amount of soil brought to the surface from each of six 50 cm depth regions was estimated for ten nest size classes (data from [35] in S2 Table) ranging from less than 1000 cm3 to about 10,000 cm3 and depths to almost 3 m. These are shown in Fig. 5, and were used to generate the equations in Table 2. The depths are coded by color, and these colors are used for depth-weighted composition of disc soil in the simulations below.


Biomantling and bioturbation by colonies of the Florida harvester ant, Pogonomyrmex badius.

Tschinkel WR - PLoS ONE (2015)

Mean size-free distribution of chamber area by decile of maximum depth.Data from Tschinkel [31].
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4368782&req=5

pone.0120407.g004: Mean size-free distribution of chamber area by decile of maximum depth.Data from Tschinkel [31].
Mentions: These distributions, volumes and frequencies produce the overall rates of biomantling. What remains to be estimated is the relative amount of soil brought up from various depths. To this end, Tschinkel [31] showed that the "size-free shape" of the nest does not change with nest size (i.e. the proportion of total nest area (volume) found at each proportion of maximum depth is invariant) (Fig. 4). Therefore, given a total nest volume derived from the disc area, the distribution of this volume in relation to depth can be estimated from the relationship in Fig. 4. For the simulations, the amount of soil brought to the surface from each of six 50 cm depth regions was estimated for ten nest size classes (data from [35] in S2 Table) ranging from less than 1000 cm3 to about 10,000 cm3 and depths to almost 3 m. These are shown in Fig. 5, and were used to generate the equations in Table 2. The depths are coded by color, and these colors are used for depth-weighted composition of disc soil in the simulations below.

Bottom Line: These parameters were used in a simulation to estimate the amount of soil mantled over time by the observed population of P. badius colonies.Spread evenly, P. badius mantling would create a soil layer averaging 0.43 cm thick in a millennium, with 10-15% of the soil deriving from depths greater than 1 m.Biomantling by P. badius is discussed in the context of the ant community of which it is a part, and in relation to literature reports of ant biomantling.

View Article: PubMed Central - PubMed

Affiliation: Dept. of Biological Science, Florida State University, Tallahassee, Florida, United States of America.

ABSTRACT
In much of the world, soil-nesting ants are among the leading agents of biomantling and bioturbation, depositing excavated soil on the surface or in underground chambers. Colonies of the Florida harvester ant, Pogonomyrmex badius excavate a new nest once a year on average, depositing 0.1 to 12 L (3 L average) of soil on the surface. Repeated surveys of a population of about 400 colonies yielded the frequency of moves (approximately once per year), the distance moved (mean 4 m), and the direction moved (random). The area of the soil disc correlated well with the volume and maximum depth of the nest, as determined by excavation and mapping of chambers. The population-wide frequency distribution of disc areas thus yielded the frequency distribution of nest volumes and maximum depths. For each surveyed colony, the volume of soil excavated from six specified depth ranges and deposited on the surface was estimated. These parameters were used in a simulation to estimate the amount of soil mantled over time by the observed population of P. badius colonies. Spread evenly, P. badius mantling would create a soil layer averaging 0.43 cm thick in a millennium, with 10-15% of the soil deriving from depths greater than 1 m. Biomantling by P. badius is discussed in the context of the ant community of which it is a part, and in relation to literature reports of ant biomantling.

No MeSH data available.