Macroinvertebrate colonization of two different tree species leaf packs (native vs. introduced) in a Mediterranean stream

Abstract

Allochthonous leaf litter from riparian vegetation represents the main energy source in small lotic systems, where canopy limits autochthonous primary production. In this study, leaf packs of two tree species (the native Salix neotrichia and the introduced Populus x canadensis) were positioned in the Fardes Stream (southern Spain) to analyze the macroinvertebrate colonization. On two dates, leaf packs were removed, and colonizing macroinvertebrates were collected and identified; at the same time, Surber samples were collected to characterize the riverbed macroinvertebrate coenosis. Leaf packs attracted rich and varied communities of benthic macroinvertebrates, with an increase of the abundance of most taxa over time. No significant differences were found between the colonizing communities of the two leaf types. Some macroinvertebrate species showed a preference for leaf packs, probably due to trophic or hydrologic factors. Considering functional feeding groups, increases in shredders and scrapers and decreases in predators and filterers were detected over time, while collector-gatherers almost did not change in abundance.

The effect of large predators on the decomposition rate and the macroinvertebrate colonization pattern of leaves in a Mediterranean stream

“…Though a total of 35 taxa were recorded in the riverbed, 32 in big and 34 in medium during the study period, a lower number of families coexisted in each moment. These values are quite similar to those found by Peralta‐Maraver et al () in a previous litter bag colonization experiment in the same stream. The number of coexisting families was always lower in the litter bags than in the riverbed, indicating that some taxa actively avoided this kind of habitat and did not use it either as a food source or as shelter.…”

“…This finding is also true even if we do not consider those families with the scarcest abundances (see “Number of families without singletons or doubletons” in Supporting Information 1), that is, those that could be only migrants. In fact, Peralta‐Maraver et al () already identified some of these taxa as families with a negative electivity of leaves. This situation is the case, for instance, for Elmidae or Ancylidae, for which trophic resources (mainly biofilm, as they behave as grazers) could be scarcer in the litter bags than in other microhabitats of the stream reach, or Ephemeridae, which prefer inhabiting sites with fine sediments.…”

Rainbow Trout diets and macroinvertebrates assemblages responses from watersheds dominated by native and exotic plantations

“…This low preference of macroinvertebrates, may be related to the characteristics of the eucalyptus leaves, for example the quantity of nutrients, and presence of secondary compounds (e.g. tannins) (Peralta-Maraver et al, 2011). It is difficult to conclude which of these factors accounts for the changes observed in our study, so future work should focus on resolving which are the principal consequences produced by eucalyptus species affecting benthic aquatic macroinvertebrates.…”

Comparing biotic drivers of litter breakdown across stream compartments

“…Both compartments are certainty distinct environments with characteristic abiotic conditions (Peralta‐Maraver, Galloway, et al, ; Peralta‐Maraver, Galloway, et al, ), and it is likely that litter breakdown differs between these zones. The majority of leaves falling into streams and rivers are trapped by streambed structures, mostly cobbles and woody debris, forming leaf packs that are processed in the BZ (Cummins, Petersen, Howard, Wuycheck, & Holt, ; Peralta–Maraver, ). However, a substantial part of the total leaf litter entering streams and rivers is buried and stored in the HZ as a consequence of storm events, flooding and sediment movements (Cornut et al, ).…”