, 1997 and Hellsten et al., 1999) and Loktak (India) (Singh and Khundrakpam, 2011). Other lakes are largely turbid such as the Boraphed Reservoir in Thailand (Mizuno and Mori, 1970). Whether these lakes indeed show alternative stable states has not been proven by this review and would require further research. Model results also indicated 3 lakes to have habitats that are particularly suitable for macrophyte growth mainly because of their shallowness. These are Lake Upemba (Congo), Lake Istokpoga (USA) and Lake Tathlina (Canada). Indeed,

macrophytes are abundantly present in Lake Upemba. Also in Lake Istokpoga macrophytes are flourishing. Despite great effort, removal of excess macrophytes from this lake had only a temporary effect (O’Brien and Hapgood, 2012) indicating that Lake Istokpoga has conceivably only one stable state which is macrophyte dominated. Cilengitide chemical structure Whether Lake Tathlina (Canada) is also macrophyte dominated is not clear because data are not available. The majority Cell Cycle inhibitor of the lakes fall outside the suggested domain with the possibility of having macrophytes. These large shallow lakes are expected to be prone to the size effect. This is not surprising, since they have a large fetch or depth reducing

the window of opportunity for macrophytes ( Fig. 2A, process 1). However, this contrasts to observations in the literature showing that in most of the lakes macrophytes had a chance to grow at least some time in history ( Table 1). In some of the lakes this can be explained by natural water fluctuations. A drop in water level restricts the surface area where size effects prevail. For example, the water fluctuations in Lake Chad make the lake switch from a great large inland ‘sea’ in wet periods to a marshy macrophyte-rich area in dry periods ( Leblanc et al., 2011). Additionally, in Lake Beyşehir and Lake Uluabat (both in Turkey) receding water levels made large areas suitable for macrophyte Avelestat (AZD9668) growth, whereas higher water levels prevented macrophytes to grow ( Beklioglu

et al., 2006). Water level fluctuations can thus lead to alternating behaviour of lakes to eutrophication, which will be showing a turbid state during high water levels, a macrophyte dominated state during extreme low water levels and possibly alternative stable states in between ( Blindow et al., 1993 and Van Geest et al., 2005). However, fluctuating water levels are not the sole explanation of macrophyte presence in all lakes. So far, the effects of spatial heterogeneity have been ignored. If spatial heterogeneity is accounted for, as with the data of Taihu, there may well be compartments within large shallow lakes that are more sheltered or shallower and thereby being suitable for macrophyte growth.