Patch Dynamics in Lotic Systems: The Stream as a Mosaic

Abstract

This paper applies concepts of landscape ecology and patch dynamics to lotic systems. We present a framework for the investigation of pattern and process in lotic ecosystems that considers how specific patch characteristics determine biotic and abiotic processes over various scales. Patch characteristics include: size, size distribution within the landscape, juxtaposition, diversity, duration, and mechanisms affecting patch formation. Several topics of current interest in lotic ecology are examined from a patch-dynamics perspective: (1) response of periphyton communities to nutrient patches; (2) effects of patch dynamics on nutrient spiralling; (3) riparian patch dynamics and effects of leaf litter characteristics on lotic food webs; (4) beaver-induced patch dynamics; and (5) patch dynamics of river floodplains. We conclude that a patch-dynamics perspective coupled with a strong experimental approach can enhance the utility and predictive power of unifying concepts in lotic ecology, such as the river continuum hypothesis and nutrient spiralling, through its focus on organismal and process-specific building blocks of lotic systems. The effectiveness of a patch-dynamics approach as a framework for the study of lotic systems lies in the strength of the linkage between reductionist and wholestream perspectives.

Diet and ecomorphological relationships of an endemic, species-poor fish assemblage in a stream in the Iguaçu National Park

“…One, reported by Schoener (1974) and other investigators (MacArthur & Pianka, 1966;MacArthur & Levins, 1964;Ross, 1986) is spatial segregation, which could more consistently contribute to the differentiation of niches in narrower tracks. Therefore, low species richness does not necessarily lead to wider trophic breadth, but on the other hand, specialized trophic niches would be a consequence of morphological limitations associated with feeding resources in habitat mosaics (Pringle et al, 1988). This hypothesis gains support because the dietary overlap of this assemblage was high only for those congeneric species with similar morphologies.…”

Importance of floodplain waters for the conservation of chironomid (Diptera) biodiversity in a 6thorder section of the Garonne river (France)

“…This dimension includes the whole alluvial plain, defined as a mosaic of homoge neous patches on the physico-chemical and biological plan (Johnston & Naiman 1987, Pringle et al 1988, as well as the transverse bi-directional exchanges control ling interactions within this mosaic (Amoros & Roux 1988, Junk et al 1989, Bayley 1995.…”

Atyid Shrimps Production and Biomass Turnover in Masanga Mabe Equatorial Rain-Forest Stream of Congo Basin (Kisangani, DR Congo)

“…Actually, Benke [36] thinks that the quantity and the quality of foods constitute the most important limiting factors for the benthic production. Murphy et al [39], Pringle et al [40] and Dangles [41] affirm that the benthic accumulation of the allochthonous detritus in the forest headwaters streams is an important resource colonized by macroinvertebrates for eating and having shelter. Chadwick and Huryn [42] and Smock et al [43], studying the role of the habitat in the determination of macrobenthic production, have concluded that the production was always high on the bottom rich in plant debris than that of sandy one.…”