INVESTIGADORES
IRIBARNE Oscar Osvaldo
artículos
Título:
Conditional responses of organisms to habitat structure: an example from intertidal mudflats
Autor/es:
GUTIÉRREZ, J; O. IRIBARNE
Revista:
OECOLOGIA
Editorial:
Springer
Referencias:
Lugar: NY; Año: 2004 vol. 139 p. 572 - 582
ISSN:
0029-8549
Resumen:
Abstract Habitat structure is often assumed to be a
predictor of habitat function. However, habitat structure
may be insufficient to predict the functional significance
of a habitat if the level of resources in the habitat is a
consequence of the interaction between the habitat structure
and physical or biological factors. In this study, we
investigated whether depressions in tidal flat sediments
generated by stout razor clams, Tagelus plebeius, affect the
spatial patterns of pit digging by deposit-feeding burrowing
crabs, Chasmagnathus granulata. The pits dug by
crabs while feeding overlapped with clam siphon holes at
a frequency higher than expected at random, and
measurements of pit-digging by crabs integrated over
several days indicated a higher frequency of feeding in the
sediment of depressions. The daily frequency of pitdigging
by crabs in depressions was positively related to
the organic matter content of their sediments, but was
significantly higher than the frequency of pit-digging away
from clam siphon holes only after events of high bedload
sediment transport, when the organic matter in the
sediments of these depressions peaked. This example
demonstrates the conditional nature of the relationship
between habitat structure and function by illustrating how
a physical processbedload sediment transportmay
introduce variation in the function that depressions play as
feeding sites for burrowing crabs. Published information
suggests that such conditional responses of organisms to
habitat structure: (1) occur in a variety of habitats; (2)
involve a variety of structures either of biotic or abiotic
origin; and (3) are the consequence of either physical or
biological controls that vary in importance according to
the general mechanism through which habitat structure
affect resources. This broad experimental evidence
suggests that the accuracy of predictive models linking
habitat structure and function can be improved by
incorporating a mechanistic perspective that allows recognition
of the potential for conditional responses of
organisms to habitat structure.Habitat structure is often assumed to be a
predictor of habitat function. However, habitat structure
may be insufficient to predict the functional significance
of a habitat if the level of resources in the habitat is a
consequence of the interaction between the habitat structure
and physical or biological factors. In this study, we
investigated whether depressions in tidal flat sediments
generated by stout razor clams, Tagelus plebeius, affect the
spatial patterns of pit digging by deposit-feeding burrowing
crabs, Chasmagnathus granulata. The pits dug by
crabs while feeding overlapped with clam siphon holes at
a frequency higher than expected at random, and
measurements of pit-digging by crabs integrated over
several days indicated a higher frequency of feeding in the
sediment of depressions. The daily frequency of pitdigging
by crabs in depressions was positively related to
the organic matter content of their sediments, but was
significantly higher than the frequency of pit-digging away
from clam siphon holes only after events of high bedload
sediment transport, when the organic matter in the
sediments of these depressions peaked. This example
demonstrates the conditional nature of the relationship
between habitat structure and function by illustrating how
a physical processbedload sediment transportmay
introduce variation in the function that depressions play as
feeding sites for burrowing crabs. Published information
suggests that such conditional responses of organisms to
habitat structure: (1) occur in a variety of habitats; (2)
involve a variety of structures either of biotic or abiotic
origin; and (3) are the consequence of either physical or
biological controls that vary in importance according to
the general mechanism through which habitat structure
affect resources. This broad experimental evidence
suggests that the accuracy of predictive models linking
habitat structure and function can be improved by
incorporating a mechanistic perspective that allows recognition
of the potential for conditional responses of
organisms to habitat structure.Tagelus plebeius, affect the
spatial patterns of pit digging by deposit-feeding burrowing
crabs, Chasmagnathus granulata. The pits dug by
crabs while feeding overlapped with clam siphon holes at
a frequency higher than expected at random, and
measurements of pit-digging by crabs integrated over
several days indicated a higher frequency of feeding in the
sediment of depressions. The daily frequency of pitdigging
by crabs in depressions was positively related to
the organic matter content of their sediments, but was
significantly higher than the frequency of pit-digging away
from clam siphon holes only after events of high bedload
sediment transport, when the organic matter in the
sediments of these depressions peaked. This example
demonstrates the conditional nature of the relationship
between habitat structure and function by illustrating how
a physical processbedload sediment transportmay
introduce variation in the function that depressions play as
feeding sites for burrowing crabs. Published information
suggests that such conditional responses of organisms to
habitat structure: (1) occur in a variety of habitats; (2)
involve a variety of structures either of biotic or abiotic
origin; and (3) are the consequence of either physical or
biological controls that vary in importance according to
the general mechanism through which habitat structure
affect resources. This broad experimental evidence
suggests that the accuracy of predictive models linking
habitat structure and function can be improved by
incorporating a mechanistic perspective that allows recognition
of the potential for conditional responses of
organisms to habitat structure.Chasmagnathus granulata. The pits dug by
crabs while feeding overlapped with clam siphon holes at
a frequency higher than expected at random, and
measurements of pit-digging by crabs integrated over
several days indicated a higher frequency of feeding in the
sediment of depressions. The daily frequency of pitdigging
by crabs in depressions was positively related to
the organic matter content of their sediments, but was
significantly higher than the frequency of pit-digging away
from clam siphon holes only after events of high bedload
sediment transport, when the organic matter in the
sediments of these depressions peaked. This example
demonstrates the conditional nature of the relationship
between habitat structure and function by illustrating how
a physical processbedload sediment transportmay
introduce variation in the function that depressions play as
feeding sites for burrowing crabs. Published information
suggests that such conditional responses of organisms to
habitat structure: (1) occur in a variety of habitats; (2)
involve a variety of structures either of biotic or abiotic
origin; and (3) are the consequence of either physical or
biological controls that vary in importance according to
the general mechanism through which habitat structure
affect resources. This broad experimental evidence
suggests that the accuracy of predictive models linking
habitat structure and function can be improved by
incorporating a mechanistic perspective that allows recognition
of the potential for conditional responses of
organisms to habitat structure.bedload sediment transportmay
introduce variation in the function that depressions play as
feeding sites for burrowing crabs. Published information
suggests that such conditional responses of organisms to
habitat structure: (1) occur in a variety of habitats; (2)
involve a variety of structures either of biotic or abiotic
origin; and (3) are the consequence of either physical or
biological controls that vary in importance according to
the general mechanism through which habitat structure
affect resources. This broad experimental evidence
suggests that the accuracy of predictive models linking
habitat structure and function can be improved by
incorporating a mechanistic perspective that allows recognition
of the potential for conditional responses of
organisms to habitat structure.