Recovery of lotic periphyton communities after disturbance

Abstract

ABSTRACT/Periphyton communities represent potentially excellent candidates for assessing the recovery of lotto ecosystems after disturbance. These communities are ubiquitous, relatively easy to sample and measure (in terms of total community biomass), have short generation times, and may influence the recovery rates of higher trophic levels. The first section of this article analyzes how site availability, species availability, and differential species performance influence periphyton successional dynamics. This background information provides a foundation for understanding how pertphytic organisms respond after a disturbance. The second section of this article analyzes how periphyton communities respond to four different types of disturbance (flood events, desiccation, organic nutrient enrichment, and toxic metal exposure). Although data are limited, it is concluded that the fast growth rates and short generation times of periphytic organisms, coupled with their flexible life history strategies and good dispersal ability, allow Iotic periphyton communities to recover relatively quickly after a disturbance. In addition, disturbance type and severity, local environmental conditions, and site-specific factors also will influence recovery rates.Future research needs include a better understanding of: (1) what periphyton property(ies) would serve as the best index of recovery; (2) whether or not the robustness of this index varies among different environments and different disturbances; (3) interactions between autotrophs and heterotrophs within the periphyton mat, particularly with respect to nutrient cycling; (4) competitive interactions among organisms; (5) functional redundancy of organisms; and (6) the influence of the riparian zone and channel geomorphology on periphyton recovery rates.Periphyton communities in lotic ecosystems are complex assemblages comprised of autotrophs (algae) and heterotrophs (fungi, bacteria, protozoa), attached to substrates, and often embedded in a polysaccharide matrix. Periphyton communities possess properties that make them particularly useful in evaluating the rates at which recovery occurs in lotic ecosystems following disturbance. For example, they are ubiquitous and relatively easy to sample and measure (in terms of total community biomass). In addition, compared to terrestrial biota, many periphytic organisms have very short generation times (Cairns 1982, Baars 1983. This permits periphyton growth to be monitored through many generations and different successional seres between disturbance events, potentially resulting in a better understanding of recovery dynamics. Finally, because periphyton is a high-quality food resource for many lotic invertebrates (Lamberti and Moore 1984,

Effects of Sedimentation and Turbidity on Lotic Food Webs: A Concise Review for Natural Resource Managers

“…The influence of increased sedimentation on lotic food webs is pervasive and begins at primary trophic levels. Sediment in transport can have an abrasive quality and can reduce the quantity of periphyton that grows on stream substrata (Steinman and McIntire, 1990). Increases in lotic turbidity can limit light penetration and therefore reduce phytoplankton production (Hoetzel and Croome, 1994).…”

The roles of environment and space in shaping stream diatom communities

“…One of the Correspondence to: Laura Virtanen. E-mail: Laura.Virtanen@ helsinki.fi most significant factors leading to a decrease of algal biomass is physical disturbance (Steinman & McIntire, 1990;Stevenson et al, 1996), through substratum instability and associated abrasion, high water velocities, and abrasion by suspended sediments (Francoeur & Biggs, 2006). In addition, biotic factors, such as grazing by invertebrates and fish, may affect diatom occurrence (Feminella & Hawkins, 1995;Stevenson et al, 1996).…”

Ecological Recovery Potential of Freshwater Organisms: Consequences for Environmental Risk Assessment of Chemicals

“…For instance, in tundra ponds, a cryptomonad species became extinct during a crude-oil spill and was subsequently replaced by chrysophytes; the community did not return to its pre-disturbance composition during a study period of 6 years (Miller et al 1978 ). As pointed out by Steinmann and McIntire ( 1990 ), community structure in turn might also affect periphyton recovery time. For example, the age of periphyton communities might have an infl uence, in that young periphyton communities have a higher resistance and recover faster than older ones (Kaufman 1982 ), as older communities are more complex and dynamically fragile (May 1975 ).…”

“…Rapid recovery was frequently observed, e.g., in case studies that investigated recovery after pesticide applications in artifi cial mesocosm studies (Brock et al 2004 ; Hatakeyama et al 1994 ;Mohr et al 2008 ;Peterson and Stevenson 1992 ). A longer recovery time was observed e.g., for a periphyton community exposed to heavy metals (Steinmann and McIntire 1990 ) and for a case where the colonization of bricks (placed at a closed canopy site) was completed by lotic diatoms within 20 weeks (Robinson and Rushforth 1987 ). Long-term changes in algal communities might be the consequence of the replacement of one species by another.…”