Resilience of Alternative Stable States during the Recovery of Shallow Lakes from Eutrophication: Lake Veluwe as a Case Study

Abstract

In this paper we analyze a long-term dataset on the recovery from eutrophication of Lake Veluwe (The Netherlands). Clear hysteresis was observed in a number of ecosystem variables: the route to recovery differed significantly from the route that led to loss of clear water. The macrophyte dominated state disappeared in the late 1960s at TP above 0.20 mg l 1 , whereas its return occurred at less than 0.10 mg TP l 1. Several regime shifts resulting in the occurrence of three alternative stable states were observed over a period of 30 years. The turbid state showed resistance to change, despite a strong and prompt reduction in Chl-a following reduction of external P-loading. The most important component that determined hysteresis in the return to clear water was not internal P-loading, but a high level of nonalgal light attenuation (through sediment resuspension) maintained by the interaction between wind and benthivorous fish. Although Chara was able to re-colonize the most shallow parts of the lake, recovery stalled and for a number of years clear (above charophyte beds) and turbid (deeper parts of the lake) water co-existed, as a separate alternative state on route to full recovery. Lake-wide clear water was re-established after bream density had been reduced substantially. This allowed a return of zebra mussels to the lake, whose high filtration capacity helped in maintaining clear water. In this study, we were able to identify the main drivers of hysteresis and regime shifts, although formal demonstration of cause and effect was not possible on the basis of field data alone. We argue that resilience of the present clear water state of Lake Veluwe very much depends on sizable populations of a few keystone species, especially Chara (stoneworts) and Dreissena (zebra mussels), and that careful management of these species is equally important as control of nutrients. Lake management should strive to maintain and strengthen resilience of the ecosystem, and this should offer protection against a renewed collapse of the clear state.

Does the responses of Vallisneria natans (Lour.) Hara to high nitrogen loading differ between the summer high-growth season and the low-growth season?

“…Worldwide, with the increasing eutrophication of shallow lakes, a decline in the abundance of submersed macrophytes has often been seen (Körner, 2002;Ibelings et al, 2007;Wang et al, 2014), producing substantially negative impacts on the ecosystem structure, functioning, and services of shallow lakes (Scheffer, 1998;Jeppesen et al, 1998). Most scientists agree that phytoplankton shading promoted by increasing inputs of phosphorus is an underlying cause of the decreasing abundance, but the role of nitrogen has received increasing attention in recent years (Moss, 2001;Jeppesen et al, 2007;Moss et al, 2013).…”

Importance of climate change-physical forcing on the increase of cyanobacterial blooms in a small, stratified lake

“…This phenomenon has traditionally been attributed to anthropogenic perturbations, particularly phosphorus (P) enrichment (Schindler, 1974). Lake eutrophication has decreased in the last 20-30 yrs, at least in western countries (Pomati et al, 2012), and eutrophied lakes have in Importance of climate change-physical forcing on the increase of cyanobacterial blooms in a small, stratified lake Dolores o n l y many cases recovered, or are recovering after reduction or elimination of nutrient sources (Edmondson and Leman, 1981;Ruggiu et al, 1998;Jeppesen et al, 2005;Ibelings et al, 2007). In some cases, increases in temperature may offset the effects of oligotrophication by promoting the expansion of some forms of CYAN (Kosten et al, 2012).…”

Restoring macrophyte diversity in shallow temperate lakes: biotic versus abiotic constraints

“…The ongoing eutrophication of freshwater bodies (Carpenter et al, 1998;Tilman et al, 2001) has induced a decline or disappearance of macrophytes from many shallow water ecosystems Brouwer & Roelofs, 2001;Gulati & van Donk, 2002;Lamers et al, 2002). This has been observed in many shallow lakes in densely populated areas, for instance in the Loosdrecht lakes (Best et al, 1984;Gulati & van Donk, 2002;Van de Haterd & Ter Heerdt, 2007) and Lake Veluwemeer (Van den Berg et al, 1999;Ibelings et al, 2007) in The Netherlands, Lake Fure (SandJensen et al, 2008) and Lake Arresø in Denmark and the Müggelsee in Germany (Korner, 2001). Increased nutrient availability can initially stimulate macrophyte growth as long as the water remains clear (Lombardo & Cooke, 2003;Nagasaka, 2004;Feuchtmayr et al, 2009).…”