Year of compilation: 2001
Non-bird biodiversity: Rare plants include Ferraria foliosa, F. densepunctulata, Cerycium venoum (presumed extinct) and Cullumia floccosa. The fish Barbus burgi (CR) has a global range restricted to the Verlorenvlei system and some of the upper catchment streams of the Berg river. Among reptiles, the IBA lies in the centre of the ranges of several Namaqualand endemics, most of which have been recorded in the vicinity and may be present in the succulent Karoo terrestrial vegetation surrounding the wetland: Homopus signatus, Bitis schneideri (VU), B. cornuta, Acontias litoralis, Typhlosaurus caecus, Scelotes sexlineatus, Meroles knoxii, Cordylus cataphractus (VU), C. macropholis, Gerrhosaurus typicus (LR/nt), Bradypodion occidentale and Pachydactylus austeni.
This wetland is of great significance, especially in terms of its large area, the diversity of its habitats, the large populations of waterbirds that it supports, and the relative scarcity of similar habitats in the Western Cape. Despite being one of the most important estuarine/lacustrine systems in South Africa, Verlorenvlei does not have any formal protection status and neither statutory control nor any form of management is currently in existence. The Ramsar-designated land is state-owned and is managed by Cape Nature Conservation.
Several man-made obstructions disrupt water flow in the system, a concrete causeway, a rubble causeway at the railway bridge, and road causeways (500 m, 1 km and 2.6 km upstream of the mouth) all prevent natural flow and disturb the sensitive ecological functioning of the system. These obstructions disrupt hydrological fluctuations within the wetland, causing flooding upstream, extensive siltation and reduction of freshwater load into the estuary, and also prevent fish migration. As such, urgent action is required to maintain free water movement in Verlorenvlei as a whole; unnecessary obstructions, especially the illegal causeway near the mouth, should be removed, while necessary crossing points should be modified to return the system to a natural state. Verlorenvlei may become irreparably damaged if conservation action is not rapidly forthcoming.
The land surrounding the lake is privately owned, and the vlei faces several threats from intensive farming practices in this area. The surrounding vegetation has become considerably degraded through extensive agricultural and grazing pressure. The introduction of mechanized irrigation systems, which use underground lake water, may impact the lake considerably. Non-native fish compete with indigenous freshwater species and alter the vegetation structure, potentially altering system dynamics. Similarly, the invasive non-native tree Acacia cyclops was introduced to stabilize the coastal dunes; it has now spread throughout the area where it threatens the indigenous vegetation.
BirdLife International (2020) Important Bird Areas factsheet: Verlorenvlei Estuary. Downloaded from http://www.birdlife.org on 27/11/2020.