On the prevalence and dynamics of inverted trophic pyramids and otherwise top-heavy communities.
Ecol Lett
; 21(3): 439-454, 2018 03.
Article
en En
| MEDLINE
| ID: mdl-29316114
ABSTRACT
Classically, biomass partitioning across trophic levels was thought to add up to a pyramidal distribution. Numerous exceptions have, however, been noted including complete pyramidal inversions. Elevated levels of biomass top-heaviness (i.e. high consumer/resource biomass ratios) have been reported from Arctic tundra communities to Brazilian phytotelmata, and in species assemblages as diverse as those dominated by sharks and ants. We highlight two major pathways for creating top-heaviness, via (1) endogenous channels that enhance energy transfer across trophic boundaries within a community and (2) exogenous pathways that transfer energy into communities from across spatial and temporal boundaries. Consumer-resource models and allometric trophic network models combined with niche models reveal the nature of core mechanisms for promoting top-heaviness. Outputs from these models suggest that top-heavy communities can be stable, but they also reveal sources of instability. Humans are both increasing and decreasing top-heaviness in nature with ecological consequences. Current and future research on the drivers of top-heaviness can help elucidate fundamental mechanisms that shape the architecture of ecological communities and govern energy flux within and between communities. Questions emerging from the study of top-heaviness also usefully draw attention to the incompleteness and inconsistency by which ecologists often establish definitional boundaries for communities.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Cadena Alimentaria
/
Ecología
Tipo de estudio:
Prevalence_studies
/
Risk_factors_studies
Límite:
Humans
País/Región como asunto:
America do sul
/
Brasil
Idioma:
En
Revista:
Ecol Lett
Año:
2018
Tipo del documento:
Article
País de afiliación:
Estados Unidos