Generalist and Specialist Feeding Crabs Maintain Discrete Trophic Niches Within and Among Estuarine Locations

Vermeiren, Peter; Abrantes, Kátya G.; Sheaves, Marcus

doi:10.1007/s12237-015-9959-x

Cited by 19 publications

(9 citation statements)

References 59 publications

(80 reference statements)

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“…Thus, more extensive research on the spatial and temporal variability of the origin of basal resources, as well as the bottom-up interactions of estuarine food webs and their relationships with other environmental factors, is needed to better understand the food web dynamics in both systems. Understanding the trophic interactions present in estuaries with a strong human presence is crucially important for defining proper management and conservation strategies 80 . Furthermore, the management of factors that influence an estuary, such as freshwater discharges and urban and agricultural wastes, can regulate inputs of basal resources and modulate a phytoplankton or detrital dominated food web.…”

Section: Discussionmentioning

confidence: 99%

Human pressures on two estuaries of the Iberian Peninsula are reflected in food web structure

Donázar-Aramendía

Sánchez-Moyano

García-Asencio

et al. 2019

Sci Rep

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As a result of the increased urban and agricultural development in coastal environments, estuaries are among the most modified and threatened aquatic ecosystems. This study used stable isotopes to examine the effects of human impacts by contrasting the food web structures of two Iberian estuaries exposed to different degrees of human pressure. More complex feeding pathways were found in the more altered estuary (Guadalquivir). Greater spread among species along the carbon axis suggests that the primary consumers exploit organic matter with various origins, whereas different nitrogen signals of the secondary consumers suggest that they feed on different suites of prey. In contrast, the similar isotopic signals of secondary consumers in the relatively little influenced estuary (Guadiana) suggests similarity in diet composition and feeding on the same organic matter sources. Understanding trophic interactions in estuaries is vital for defining proper management and conservation, and the preliminary data provided here are one step in this direction.

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Section: Discussionmentioning

confidence: 99%

Human pressures on two estuaries of the Iberian Peninsula are reflected in food web structure

Donázar-Aramendía

Sánchez-Moyano

García-Asencio

et al. 2019

Sci Rep

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“…Recent studies have shown that inter‐tidal crabs also occupy discrete habitats according to environmental conditions related, for instance, to availability of structural complexity (Vermeiren & Sheaves ), generalist or specialized diet (Vermeiren et al . ) or food distribution (Silva et al . ).…”

Section: Discussionmentioning

confidence: 99%

Variations in crab claw morphology and diet across contrasting inter‐tidal habitats

et al. 2017

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Crabs are important predators of inter‐tidal ecosystems, controlling the abundance and distribution of their prey populations. Often the same crab species occupies several habitats and, although their effects on prey have been quantified across habitats, crabs’ dietary and morphological responses to differing environmental influences have been overlooked. Here, we used the crabs Eriphia verrucosa and Pachygrapsus marmoratus as model species to examine differences in claw morphometry – size and wear – and diet between rocky shore and heterogeneous sand flat habitats. We predicted that, intra‐specifically, crabs from rocky shores would consume more hard‐shelled prey owing to their high availability and consequently, would display chelipeds with the following claw characteristics: a higher degree of claw damage, stronger musculature (higher propel height) and increased mechanical advantage (defined as the ratio of input lever length to output lever length) than crabs in the heterogeneous sand flat habitats. Sampling was performed in heterogeneous sand flat habitats and rocky shores of the Central Portuguese coast. For each crab species, carapace width, diet composition and several claw morphometric measures were recorded, revealing significant intra‐specific differences (using multivariate analysis) between shore types. We found that E. verrucosa and P. marmoratus consumed more hard prey on rocky shore than on sand flat habitats, which resulted in rocky shore crabs having more accentuated dentition wear and larger musculature than their sand flat habitat counterparts. We suggest that the strong response of crab claw morphometry to environmentally induced diet variations is an important mechanism in the successful adaptation of crab species to inhabit differing habitats. A major implication is that the impact of the same species on prey may vary largely with habitat type as a result of predation efficiency varying with claw condition.

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“…might reflect the more omnivorous diet and higher trophic position (including opportunistic carnivory) compared to the elongated claws of Tubuca spp. which often feed on microphytobenthos and scoop up mud rather than crush prey (Vermeiren et al 2015). Freire et al (1996) identified that the portunid L. navigator, with a diet composed mainly of sea weeds and soft organisms, had less mobile chela with lower muscle ratios compared to the portunid L. depurator which consumed more hard-shelled prey.…”

Section: Habitat Characteristics-morphology Linkagesmentioning

confidence: 99%

“…Freire et al (1996) identified that the portunid L. navigator, with a diet composed mainly of sea weeds and soft organisms, had less mobile chela with lower muscle ratios compared to the portunid L. depurator which consumed more hard-shelled prey. Vermeiren et al (2015) studying spatial variation in diet preferences among intertidal mangrove crabs identified that M. frontalis and Metopograpsus latifrons displayed a more opportunistic diet preference, able to shift among locations, compared to the specialized diet of T. coarctata and T. seismella. However, whether this diet opportunism among locations is also evidenced in spatial variation in claw morphologies is not yet known.…”

Section: Habitat Characteristics-morphology Linkagesmentioning

confidence: 99%

Habitat, Sexual and Allometric Influences on Morphological Traits of Intertidal Crabs

Vermeiren

Lennard

Trave

2020

Estuaries and Coasts

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Intertidal crabs display distinct morphological traits that allow differential interactions with biotic and abiotic features of the intertidal landscape, but are also influenced by allometry and sexual selection. This study aimed to explore the influence of sexual, allometric and habitat factors on morphological variation in the intertidal mangrove crab assemblage. A standardized photographic protocol was developed using readily available, low-cost technology to capture the morphology of carapaces and claws as sets of Cartesian landmarks. Digitization errors were 1 to 2 orders of magnitude smaller than the variation among individuals. In Tubuca seismella and Tubuca signata (superfamily Ocypodoidea), species that have traditionally been studied for sexual dimorphism, standardized major claw sizes were 2.8 and 3.7, respectively, times larger for males than females. Sexual dimorphism in claw size was also observed for Metopograpsus frontalis and Parasesarma longicristatum (superfamily Grapsoidea), with the largest claw in males being 15% and 33%, respectively, larger than in females. In contrast to size, claw shape did not relate to sex, except for T. seismella. Carapace shape, although variable among individuals and displaying asymmetry, was unrelated to sex. Claw and carapace shapes displayed high correlations, with values around 0.78. Carapace shapes grouped into taxonomic families and linked to habitat preferences, while claw shapes varied along a taxonomic gradient. These results complement studies on crab morphology that focus on specific factors or species, and stress the importance of multiple, interacting factors including sexual, allometric and habitat influences as drivers of morphological trait variability.

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Generalist and Specialist Feeding Crabs Maintain Discrete Trophic Niches Within and Among Estuarine Locations

Cited by 19 publications

References 59 publications

Human pressures on two estuaries of the Iberian Peninsula are reflected in food web structure

Human pressures on two estuaries of the Iberian Peninsula are reflected in food web structure

Variations in crab claw morphology and diet across contrasting inter‐tidal habitats

Habitat, Sexual and Allometric Influences on Morphological Traits of Intertidal Crabs

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