Short-term colonization dynamics of macroinvertebrates in restored channelized streams

Abstract

Macroinvertebrate colonization of restored rivers is a function of dispersal into the restored reach and its suitability for population establishment. To maximize potential for colonization success, spatial considerations such as distance to colonizer source pools and dispersal pathways must be included in restoration planning. Unfortunately, the dispersal abilities of macroinvertebrates and ecological importance of different dispersal modes for colonization are still poorly understood. We used a field experiment that controlled colonization by passive drift and allowed distinction between active upstream aquatic and active/passive aerial dispersal, thus testing their differential importance during colonization of experimentally restored stream reaches. Two agricultural streams emanating below culverts were longitudinally separated along the first 30 m and one stream side each was covered with a fine-mesh net to limit aerial dispersal.Colonization of manually disturbed background and experimentally introduced cobble substrate was investigated over 6 months. We found that upstream instream dispersal, especially in these agricultural streams, can be rapid (days) and play an important role in the short-term colonization of restored streams. We conclude that a landscape perspective, in addition to instream measures, must be considered when attempting to restore streams dominated by agricultural and urban land use that constrains available species pools and limits dispersal pathways.

Aquatic versus Terrestrial Insects: Real or Presumed Differences in Population Dynamics?

“…Classic studies on an amphipod (not an insect), with a high propensity to drift, demonstrated that losses via the drift were trivial compared to population production [159]. Finally, upstream movement of juvenile aquatic insects can also be significant [160] and possibly offset the effects of drift dispersal, but studies have been few and some suffer from methodological shortcomings [161]. In short, the evidence that downstream drift is a dynamically important characteristic of lotic insect populations is both thin and unconvincing.…”

Connectivity and seasonality cause rapid taxonomic and functional trait succession within an invertebrate community after stream restoration

“…Remarkably, most colonization studies have been performed in terrestrial ecosystems, even though disturbance and subsequent succession is common in lotic ecosystems due to their dynamic nature [ 12 , 13 ]. Aquatic invertebrates have traits to quickly disperse to recently released habitat [ 14 – 18 ], but previous studies on stream colonization have shown that succession does not merely depend on species characteristics or time itself [ 19 ]. Invertebrate succession is rather shaped by a combination of 1) the distance between the regional species pool and new habitat [ 20 – 22 ], 2) the presence of a suitable habitat for settling and colonization [ 23 , 24 ], 3) dispersal capacity and life history traits of present species [ 17 , 25 – 28 ], and 4) the timing of dispersal [ 29 , 30 ].…”

Contributions of source populations, habitat suitability and trait overlap to benthic invertebrate community assembly in restored urban streams

“…The dispersal ability of a species, the distance to source populations and dispersal barriers represent the first filter that determines whether a restored reach will be colonised (Lake et al, 2007; Sundermann et al, 2011; Tonkin et al, 2014). Consequently, good dispersers are the first to reach those sections (Winking et al, 2016; Baumgartner & Robinson, 2017; Lorenz et al, 2018), which is expected to be most relevant in the starting phase of community recovery (Vos et al, 2023). However, dispersal capacity loses importance with increasing connectivity (Brederveld et al, 2011).…”