The wildlife of Chechnya includes a range of flora and fauna as reflected by its varying topographic and climatic conditions, with the Greater Caucasus to the south, the foreland zone the Terek and Sunza river valleys in the west and east, and the rolling plains of Nogai steppe in the north. Lake Kezenoyam in Chechnya is near the border with Dagestan and can sustain plankton growth. Salmo ezenami, a rare species of trout now critically endangered due to introduction of the invasive species European chub (Squalius cephalus), is native only to this lake and is therefore endemic to Lake Kezenoyam.