Sedgefield (on the Garden Route rather than the Western Cape proper) is actually a biodiversity hotspot because of its mix of estuaries, wetlands, forests, dunes, and fynbos. A surprisingly high number of threatened and endemic species occur there.

Some of the most notable endangered or threatened species include:

Knysna Seahorse

The most famous one. This is the only seahorse species in the world endemic to South Africa and occurs naturally in only three estuarine systems — including the Swartvlei estuary at Sedgefield. It is listed as Endangered due to its extremely small range.

Birds

The Wilderness–Sedgefield lake system is recognised internationally as an Important Bird and Biodiversity Area. Threatened bird species recorded there include:

* African Black Oystercatcher
* Knysna Warbler
* African Grass Owl
* African Finfoot
* Maccoa Duck
* Crowned Eagle

These species rely on intact wetland, forest, dune, and estuarine habitats.

Geometric Tortoise

One of South Africa's most endangered tortoises. It is mainly associated with the southwest Cape, but the broader fynbos conservation network linked to areas like Sedgefield helps support related conservation efforts.

Sedgefield Procydrela Zodariid Spider

A little-known but officially endangered spider species endemic to parts of the southern Cape fynbos region, including Sedgefield itself.

Plants & Ecosystems

Sedgefield lies within the globally important Cape Floristic Region, one of the world's richest floral kingdoms.

Threatened ecosystems around the area include:

* Coastal dune fynbos
* Freshwater wetlands
* Estuarine vegetation
* Southern Cape forest patches

These habitats support many rare orchids, ericas, proteas, and endemic fynbos species.

Pink Satyr Orchid

Is one of the interesting local orchids found from the Cape Peninsula through to Sedgefield and becoming increasingly localised and rare due to habitat loss and invasive plants.

The broader Sedgefield/Wilderness system is considered ecologically significant because it links lakes, estuaries, and indigenous forest into one of the most biologically diverse landscapes in South Africa.