Gwennap Head identified steamships were wrecked, stranded or sank in the area. There have been none since 1923. The navigation markers feature as "the Cones of Runnel" in Hammond Innes's 1940 thriller "The Trojan Horse". Gwennap Head is part of the Porthgwarra to Pordenack Point Site of Special Scientific Interest (SSSI) designated for its vegetation of waved maritime heath, and for being of considerable ornithological interest; especially for passage migrants. It is renowned for its relative abundance of passing marine bird species with many common species such as northern gannet ("Morus bassanus"), Manx shearwater ("Puffinus puffinus"), common guillemot, ("Uria aalge"), razorbill ("Alca
Summerland Peninsula Bird Area. It is home to one of the largest Little Penguin ("Eudyptula minor") breeding colonies in Australia, the second largest breeding colony of Australian Fur Seals ("Arctocephalus pusillus doriferus") in the world, one of the largest breeding colonies of Greater crested terns ("Sterna bergii") in Victoria and an important breeding ground for Short-tailed shearwaters ("Puffinus tenuirostris"). Several plants regarded as rare or threatened in either Victoria or Australia have been recorded on the peninsula, including River Swamp Wallaby-grass ("Amphibromus fluitans") listed as vulnerable in Australia. The peninsula was significantly modified by agricultural, residential and recreational developments until the 1980s