Coarse woody debris in temperate littoral zones: implications for biodiversity, food webs and lake management

Abstract

Coarse woody debris (CWD) represents a relatively stable habitat in many lakes with forested shorelines providing a living place for a wide range of species. The spatial complexity of CWD is recognized as an important factor promoting the abundance, diversity and productivity of littoral biota, mainly by providing shelters and moderating predator-prey interactions. However, little is as yet known on the response of different species to various levels of CWD complexity and the effects of the spatial arrangement of CWD on the connectivity between littoral populations. It is also unclear how CWD decay, which modifies the surface complexity of wood and the quality of food, affects the diversity of wood-associated species and trophic interactions. Further research is also needed to recognize the contribution of littoral wood to carbon sequestration and nutrient fluxes, considering factors affecting the CWD decay rate, such as wood species and environmental conditions. CWD resources are systematically depleted by shoreline development which leads to disruptions in the functioning of lake ecosystems. Attempts at restoring CWD habitat provided ambiguous effects on littoral species and therefore better understanding of the role of CWD in lake ecosystems is crucial to the development of successful restoration projects and effective management programmes.

Decay processes in woody debris influence the taxonomic and functional composition of littoral macroinvertebrates

“…Such an influence of wood has been shown in experimental studies for both macroinvertebrates and algae constituting a potential food source for invertebrates (Sabater et al 1998;Gabel et al 2008). The complex microstructure of decayed wood can also support high densities of macroinvertebrates by a provision of diverse shelters and decrease in predation events (Czarnecka et al 2014;Czarnecka 2016). Such an effect was recorded with respect to macroinvertebrate predators and their prey (Czarnecka et al 2014), although the interactions among macroinvertebrates and predatory fish were more intricate and represented a trade-off between different prey density, varied availability of refuge on undecayed and decayed wood, as well as species-specific abilities of invertebrates to find shelters in woody structures (Czarnecka et al 2014;Czarnecka 2016).…”

“…The complex microstructure of decayed wood can also support high densities of macroinvertebrates by a provision of diverse shelters and decrease in predation events (Czarnecka et al 2014;Czarnecka 2016). Such an effect was recorded with respect to macroinvertebrate predators and their prey (Czarnecka et al 2014), although the interactions among macroinvertebrates and predatory fish were more intricate and represented a trade-off between different prey density, varied availability of refuge on undecayed and decayed wood, as well as species-specific abilities of invertebrates to find shelters in woody structures (Czarnecka et al 2014;Czarnecka 2016). In our study, we observed that more decomposed wood (class 2 and 3) D r a f t provided significantly greater numbers of shelters than undecayed wood (class 1), and the wood assigned to class and both provided a similar degree of protection, as macroinvertebrates efficiently exploited spaces under loose bark, as well as pits and grooves in highly decayed wood.…”

Reservoir management: an opinion to how the scientific community can contribute

“…Considering the conservation of fishery resources, it has been proposed that pre-removal of tree vegetation in new reservoirs should be allowed only to the extent necessary to maintain acceptable water quality, even considering transient and localized hypoxic processes (Gois et al, 2012). The partial vegetation suppression provides the newly formed reservoir with the development of a complex physical habitat favoring the establishment and maintenance of trophic chains (algae, macrophyte, invertebrates, fish and birds; Brauns et al, 2011) as well as, the maintenance of various ecosystem services such as refuge and habitat for aquatic organisms used in human feeding and medicinal uses; physical barrier to retain macrophytes benefitting navigation, fishing and recreation activities (Czarnecka, 2016).…”

The Braveheart amphipod: A review of responses of invasive Dikerogammarus villosus to predation signals

“…For a benthic organism, one of the most important elements of the anti-predator strategy is related to the optimal substratum choice. In general, prey survival rate increases with the level of substratum complexity and heterogeneity (Crowder & Cooper, 1982;Holomuzki & Hoyle, 1988;Czarnecka, 2016). Therefore, the distribution of benthic invertebrates depends on the bottom character (Czarnecka et al, 2009;Jermacz et al, 2015b) and their efficiency of using available substrata as shelters (Holomuzki & Hoyle, 1988;Kobak, Jermacz & Płąchocki, 2014;.…”