Trophic discrimination of stable isotopes and potential food source partitioning by leaf-eating crabs in mangrove environments

Erik Kristensen, Shing Yip Lee, Perrine Mangion, Cintia Organo Quintana, Thomas Bruun Valdemarsen

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Diet composition of leaf-eating mangrove crabs is a puzzle among mangrove ecologists. Nutrient-poor leaf litter can in most cases not support animal growth. Food partitioning (mangrove leaves, animal tissue, and microphytobenthos [MPB]) of sesarmid and ucidid mangrove crabs from eight locations in four countries was assessed using the concentration-dependent stable isotope mixing model, IsoConc. While stable C and N isotopes have the potential to track the origin and proportion of food sources for these crabs, only few values of trophic discrimination are available. This problem was addressed here for crabs foraging on leaf litter to identify discrimination values that provide a balanced diet with sufficient nutrients (i.e., N) when combined with other food sources. The data from all mangrove locations suggest that sesarmid and ucidid crabs ingest and assimilate mixtures of available food items. Leaf litter in the form of brown leaves was always the most important C source, while animal tissue in the form live and dead “prey” or MPB in the form of diatoms at the sediment surface were the dominant N sources. Model scenarios were generated to obtain the upper thresholds of trophic 13C discrimination between the examined crab species and leaf litter, while complying with the molar C/N < 20 requirement for sustainable invertebrate nutrition. The model predicts litter 13C discrimination thresholds of +1.5‰ to +6.0‰ for sesarmid crabs and −0.3‰ to +0.6‰ for ucidid crabs. The difference is probably caused by metabolic disparities between these two crab families. Deviations in 15N discrimination have in most cases only minor influence on the model-based 13C discrimination thresholds. The present findings lead us to suggest a modified Optimal Foraging Theory for leaf-eating mangrove crabs.
Original languageEnglish
JournalLimnology and Oceanography
Volume62
Issue number5
Pages (from-to)2097-2112
ISSN0024-3590
DOIs
Publication statusPublished - 2017

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mangrove
stable isotopes
crab
crabs
stable isotope
partitioning
ingestion
food
leaves
leaf litter
plant litter
animal tissues
animal
foraging
diet
animal growth
Bacillariophyceae
nutrient
nutrients
ecologists

Cite this

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title = "Trophic discrimination of stable isotopes and potential food source partitioning by leaf-eating crabs in mangrove environments",
abstract = "Diet composition of leaf-eating mangrove crabs is a puzzle among mangrove ecologists. Nutrient-poor leaf litter can in most cases not support animal growth. Food partitioning (mangrove leaves, animal tissue, and microphytobenthos [MPB]) of sesarmid and ucidid mangrove crabs from eight locations in four countries was assessed using the concentration-dependent stable isotope mixing model, IsoConc. While stable C and N isotopes have the potential to track the origin and proportion of food sources for these crabs, only few values of trophic discrimination are available. This problem was addressed here for crabs foraging on leaf litter to identify discrimination values that provide a balanced diet with sufficient nutrients (i.e., N) when combined with other food sources. The data from all mangrove locations suggest that sesarmid and ucidid crabs ingest and assimilate mixtures of available food items. Leaf litter in the form of brown leaves was always the most important C source, while animal tissue in the form live and dead “prey” or MPB in the form of diatoms at the sediment surface were the dominant N sources. Model scenarios were generated to obtain the upper thresholds of trophic 13C discrimination between the examined crab species and leaf litter, while complying with the molar C/N < 20 requirement for sustainable invertebrate nutrition. The model predicts litter 13C discrimination thresholds of +1.5‰ to +6.0‰ for sesarmid crabs and −0.3‰ to +0.6‰ for ucidid crabs. The difference is probably caused by metabolic disparities between these two crab families. Deviations in 15N discrimination have in most cases only minor influence on the model-based 13C discrimination thresholds. The present findings lead us to suggest a modified Optimal Foraging Theory for leaf-eating mangrove crabs.",
author = "Erik Kristensen and Lee, {Shing Yip} and Perrine Mangion and Quintana, {Cintia Organo} and Valdemarsen, {Thomas Bruun}",
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pages = "2097--2112",
journal = "Limnology and Oceanography",
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Trophic discrimination of stable isotopes and potential food source partitioning by leaf-eating crabs in mangrove environments. / Kristensen, Erik; Lee, Shing Yip; Mangion, Perrine; Quintana, Cintia Organo; Valdemarsen, Thomas Bruun.

In: Limnology and Oceanography, Vol. 62, No. 5, 2017, p. 2097-2112.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Trophic discrimination of stable isotopes and potential food source partitioning by leaf-eating crabs in mangrove environments

AU - Kristensen, Erik

AU - Lee, Shing Yip

AU - Mangion, Perrine

AU - Quintana, Cintia Organo

AU - Valdemarsen, Thomas Bruun

PY - 2017

Y1 - 2017

N2 - Diet composition of leaf-eating mangrove crabs is a puzzle among mangrove ecologists. Nutrient-poor leaf litter can in most cases not support animal growth. Food partitioning (mangrove leaves, animal tissue, and microphytobenthos [MPB]) of sesarmid and ucidid mangrove crabs from eight locations in four countries was assessed using the concentration-dependent stable isotope mixing model, IsoConc. While stable C and N isotopes have the potential to track the origin and proportion of food sources for these crabs, only few values of trophic discrimination are available. This problem was addressed here for crabs foraging on leaf litter to identify discrimination values that provide a balanced diet with sufficient nutrients (i.e., N) when combined with other food sources. The data from all mangrove locations suggest that sesarmid and ucidid crabs ingest and assimilate mixtures of available food items. Leaf litter in the form of brown leaves was always the most important C source, while animal tissue in the form live and dead “prey” or MPB in the form of diatoms at the sediment surface were the dominant N sources. Model scenarios were generated to obtain the upper thresholds of trophic 13C discrimination between the examined crab species and leaf litter, while complying with the molar C/N < 20 requirement for sustainable invertebrate nutrition. The model predicts litter 13C discrimination thresholds of +1.5‰ to +6.0‰ for sesarmid crabs and −0.3‰ to +0.6‰ for ucidid crabs. The difference is probably caused by metabolic disparities between these two crab families. Deviations in 15N discrimination have in most cases only minor influence on the model-based 13C discrimination thresholds. The present findings lead us to suggest a modified Optimal Foraging Theory for leaf-eating mangrove crabs.

AB - Diet composition of leaf-eating mangrove crabs is a puzzle among mangrove ecologists. Nutrient-poor leaf litter can in most cases not support animal growth. Food partitioning (mangrove leaves, animal tissue, and microphytobenthos [MPB]) of sesarmid and ucidid mangrove crabs from eight locations in four countries was assessed using the concentration-dependent stable isotope mixing model, IsoConc. While stable C and N isotopes have the potential to track the origin and proportion of food sources for these crabs, only few values of trophic discrimination are available. This problem was addressed here for crabs foraging on leaf litter to identify discrimination values that provide a balanced diet with sufficient nutrients (i.e., N) when combined with other food sources. The data from all mangrove locations suggest that sesarmid and ucidid crabs ingest and assimilate mixtures of available food items. Leaf litter in the form of brown leaves was always the most important C source, while animal tissue in the form live and dead “prey” or MPB in the form of diatoms at the sediment surface were the dominant N sources. Model scenarios were generated to obtain the upper thresholds of trophic 13C discrimination between the examined crab species and leaf litter, while complying with the molar C/N < 20 requirement for sustainable invertebrate nutrition. The model predicts litter 13C discrimination thresholds of +1.5‰ to +6.0‰ for sesarmid crabs and −0.3‰ to +0.6‰ for ucidid crabs. The difference is probably caused by metabolic disparities between these two crab families. Deviations in 15N discrimination have in most cases only minor influence on the model-based 13C discrimination thresholds. The present findings lead us to suggest a modified Optimal Foraging Theory for leaf-eating mangrove crabs.

U2 - 10.1002/lno.10553

DO - 10.1002/lno.10553

M3 - Journal article

VL - 62

SP - 2097

EP - 2112

JO - Limnology and Oceanography

JF - Limnology and Oceanography

SN - 0024-3590

IS - 5

ER -