Cavinti Underground River and Caves Complex

The CURCC (14°16'51"N, 121°38'6"E) is located within barangay Paowin in the municipality of Cavinti, around 15 minutes drive from the municipal center. This eastern part of the province of Laguna contains part of the Sierra Madre mountain range. It has a dry season from March to May and a wet season for the other months. The southern Sierra Madre is a distinct ecological area that remains underresearched, and consists of rugged terrain which contains a number of limestone cave systems. The CURCC is surrounded by natural forest and lies around from the nearest settlement. However, there are some spots of old-growth forest. ==History and tourism==

The cave system was discovered by a local logger either in 1980 The Department of Environment and Natural Resources classifies the caves as Class II, meaning portions can be used by the public if accompanied by official guides. The water in the caves forms rivers, pools, and waterfalls. The resulting formations are a tourist draw. One formation is called the "fountain of youth", and produces safe drinking water. As the site is both managed and relatively remote, human disturbance is limited. However, a paved road constructed from the main barangay village that stops from Cathedral cave directly impacted the environment, while also resulting in more nearby construction and an increase in tourists. There is also visible damage in Minalokan cave, including stalactite mining and graffiti. ==Biodiversity==

A study published in 2023 found the site had a terrestrial vertebrate Shannon's Diversity Index of 1.771. The insectivorous species host a larger number of antibiotic-resistant bacteria than the others, possibly reflecting greater interaction with agricultural environments. There are 41 species of fungus identified, a majority being saprotrophic. Common species include Daldinia concentrica, Rigidoporus microporus, Auricularia auricula, Lentinus tigrinus, Schizophyllum commune, and Microporus xanthopus. The 41 species come from 34 genera and 20 families. This species may be part of a species complex with other Stenobrimus species, with all known Stenobrimus species being endemic to the Philippines. and Lupaeus dentatus have been found in the plant litter surrounding the caves. ==References==