Reaction of an estuarine food web to disturbance: Lindeman’s perspective

Abstract

Currently, a central demand of coastal and marine food web researchers is the search for holistic and functional ecosystem health indicators. Based on concepts directly derived from R. L. Lindeman's work (Lindeman 1942; Ecology 23:399-418), 6 estuarine food web models were analysed to assess the potential impact of multiple disturbances on the trophic state of food webs. The models described a Zostera noltii meadow and a bare sediment site in the Mondego estuary, Portugal, during 3 distinct time periods corresponding to (1) nutrient enrichment, (2) the implementation of mitigation measures, and (3) after a centenary flood. We tested 4 candidate metrics, directly derived from the trophic-dynamic concepts proposed by Lindeman (1942): food chain length, the detritivory/herbivory ratio, trophic efficiency per trophic level and mean trophic efficiency. Based on this case study, none of the metrics are yet ready to be used per se as operational metrics to quantify and interpret the impact of disturbances on the ecosystem's trophic state. Trophic efficiency appeared to be sensitive to external pressures. However, the mean trophic efficiency of the system might not be sufficient to draw conclusions about the trophic efficiency of the ecosystem: trophic efficiency should be observed at the trophic level in order to better understand cascading effects within food webs.

Plankton food-web functioning in anthropogenically impacted coastal waters (SW Mediterranean Sea): An ecological network analysis

“…The ENA indices have proved to be very useful to characterize ecosystem functioning, to describe the activity and the retention capacity as well as the level of organization and maturity of the food webs, and to detect any change in their environments (Proulx et al, 2005;Heymans et al, 2007). These indicators have been frequently used, especially to assess the impact of natural and anthropogenic pressures on coastal marine ecosystems (Belgrano et al, 2005;Niquil et al, 2014;Piroddi et al, 2015;Chaalali et al, 2016). They also provide useful information on the degree of stress and stability of food webs (Grami et al, 2008;Heymans et al, 2014;Saint-Béat et al, 2015).…”

Benthic and fish aggregation inside an offshore wind farm: Which effects on the trophic web functioning?

“…Some ENA indices, such as the redundancy, have also been linked to notions of stability (Christensen et al, 2005) such as the resilience of trophic webs to perturbations (Heymans et al, 2007). Finally, ENA indices have also been proposed as trophic descriptors of ecosystem health for the EU Marine Strategy Framework Directive (Dame and Christian 2007;Niquil et al, 2012;Rombouts et al, 2013;Niquil et al, 2014).…”

Before-After analysis of the trophic network of an experimental dumping site in the eastern part of the Bay of Seine (English Channel)

“…Ecological Network Analysis indices are powerful tools because they can link system architecture to system functioning and can reveal emergent properties (Ulanowicz, 2004). These indices have been commonly used in coastal and marine systems to assess changes in their functioning in response to perturbations (Tomczak et al, 2013;Tecchio et al, 2015;Raoux et al, 2017) and as ecosystem health indicators (Bondavalli et al, 2006;Niquil et al, 2012;Niquil et al, 2014). In fact, several emergent properties of ecological functioning can change under stress (Mukherjeer et al, 2015;Tecchio et al, 2015).…”

“…This type of joint analysis has been frequently applied to coastal and marine systems to assess changes in their functioning in response to environmental perturbations (Ortiz and Wolff 2002;Rybarczyk et al, 2003;Niquil et al, 2012;Tecchio et al, 2013Tecchio et al, , 2015. ENA indices have also been proposed as trophic descriptors of ecosystem health for the EU Marine Strategy Framework Directive (Niquil et al, 2012;Niquil et al, 2014).…”