Puerto-Princesa Subterranean River National Park

For many years, logging, road widening and conversion to agricultural land were among the main causes of deforestation with additional impacts from illegal developments for tourism (IUCN, 2015). Reports of illegal logging and commercial plantations inside the Puerto Princesa Subterranean River National Park (PPSRNP) appear to be limited to agricultural activities of resident indigenous peoples and developments outside the boundaries of the World Heritage site respectively. These issues do not pose a significant threat to either the superlative beauty of the site or its biodiversity values but require effective management to ensure the impact and threat posed from these issues do not increase. However, in recent years there has been some backlash in efforts to tackle illegal logging, with a PPSRNP ranger being shot and wounded by illegal loggers trying to haul logs within the park boundaries in 2020 (Fabro, 2020b). In 2019 illegal logging was undertaken to open an unauthorized access road leading to PPSRNP, which would expose the park to illegal activities. Active law enforcement led to the park management and other environmental authorities filing administrative charges against the illegal cutting and construction (Ibañez, 2019). Some of the community members tend to do “kaingin” or slash-and-burn farming if they cannot perform their usual livelihood regularly (De Miranda et al., 2020).

PPURNP is the most visited cave in the Philippines, welcoming over 330,000 tourists in 2019, 100,000 more than a decade earlier. Scientists have warned that unless visitation is managed, the ecological integrity of caves will be compromised (de Vivo et al., 2009). The tourism management system in place for the World Heritage site at the time of its inscription and subsequent declaration as one of the “New 7 Wonders of Nature” in 2007 did not have the capacity to accommodate the increasing influx of tourists resulting from these declarations and in particular the latter. The system was unable to deal with the increasing number of tourists and in particular their concentration of visits in the morning for short periods of time. This also led to an increase in traffic on the one road that provides access to the main tourism area. Noise and pollution are reported from tourist vans and the motorized boats (bancas) that bring visitors back and forth from the cave to Sabang (Agnelli et al., 2018). Ecological problems in the cave are mainly related to the diurnal resting of bats, which are disturbed by noise and light generated by the exponential growth in tourism. Swallows and bats are the base for life and food webs in this cave and their conservation need to be a priority (Agnelli et al., 2018). In 2014, the Protected Area Management Board increased the allowable number of visitors to a maximum of 1200 per day, based on a study of the tourism carrying capacity of the site. However, this study failed to accommodate for the concentration of visits in the morning to enable an early start to the tour of the underground river cave system. Surpassing 300,000 visitors per year since 2015, an integrated tourism management plan and a new approach for tourism were needed in order to avoid inevitable future damage to the subterranean river and cave ecosystem. Starting in 2015, sustainable eco-tourism projects were initiated, including through the Philippines-Italy Debt for Development Swap Program (Agnelli et al., 2018; Acero, 2020). The collaboration led to the adoption of a series of prescriptions to minimize the anthropic impact, including opening and closing hours, distance boats can travel in the cave, the use of light sources and audio-guides. Although it was deemed that the current annual limit of 350,000 visitors / year is within carrying capacity considering the underground climate, it was stressed that further increases (in visitor numbers as well as opening hours and number of boats entering the cave) must absolutely be avoided in order to not affect bats, swallows and the cave ecosystem (De Vivio et al., 2020). It is unclear how the damage to tourism facilities by the 2021 typhoon and the post-covid tourism context have impacted tourism management. Although the State Party in 2023 indicated that the impact of tourism on the OUV of the World Heritage site are insignificant and stable (State Party of the Philippines, 2023), it is clear that this issue merits ongoing attention and action.

In the past, reports have identified the threat of river pollution due to both legal and illegal activities in the catchment of the underground river. The State Party still identifies water pollution as a current threat even if decreasing (State Party of the Philippines, 2023). There is a need for the issue to be dealt with in the updated management plan, as well as a need to provide regular community awareness campaigns and to establish an integrated land use plan to ensure long-term conservation of the natural values of the site (UNEP-WCMC, 2011). In addition to ongoing programmes promoting sustainable farming, environmental compliance with water and solid waste management among the growing community and tourism related establishments will be dealt with in new strategic management plan, which has been pending for many years, as part of the attempt to address pollution issues.

Illegal wildlife trade has been noted as a relatively recently emerging threat to the site and its biodiversity and is a general issue and threat across the island of Palawan. Several alarming reports regarding illegal trafficking of the Philippine Pangolin (Manis culionensis), which is only found on Palawan, have recently been published (Gomez and Sy, 2018; PCSD, 2019), including accounts of poaching in both the Puerto Princesa Subterranean River National Park (PPSRNP) and other protected areas on the island (Abano, 2019). A 2020 report published by TRAFFIC found a worrying increase in Philippine Pangolins confiscated from the illegal trade in the Philippines in just the last two years (Sy and Krishnasamy, 2020), although it is not known if any of these were poached in the PPSRNP. It is estimated that Philippine Pangolins have declined up to 95% in the last 40 years and it continues to face pressure (Alberts, 2020; PCSD, 2020). However, some Philippine Pangolins confiscated from the illegal trade have been released back in PPSRNP, as it is seen as one of the safest areas for Pangolins on Palawan (PCSD, 2020; IUCN Consultation, 2020b). The Palawan Council for Sustainable Development also report on large confiscations of marine species, such as turtles and sharks from around the island (Estoya et al., 2017). Despite the lack of reports of illegal wildlife trade impacting species within the World Heritage site, there is increasing concern for a number of species including the Philippine Cockatoo (Cacatua haematuropygia) and the Palawan Forest Turtle (Siebenrockiella leytensis), which are found within the site, after an increase in the number of confiscations involving these critically endangered species. During the Covid-19 pandemic, park rangers have continued to monitor the site, as there is a perceived risk that the lack of income from tourism might drive an increase in illegal poaching, logging and destructive fishing practices (Fabro, 2020a; Miranda, 2020). However, decades of marine conservation in PPSRNP is now helping to provide locals with abundant fish harvests, and to support to the recovery plan of the community, PPSRNP has been distributing relief goods including moringa seedlings, which also helps wildlife conservation as it is an important food source, particularly for the Katala bird (Ganancial and Sandig, 2000). In conclusion, for the World Heritage site specifically, the illegal wildlife trade is currently seen as a low threat given that the majority of the trade and illegal collection is happening in the broader Palawan. In 2023 the State Party reported how the threat of poaching, subsistence hunting and collection of wild plants was decreasing (State Party of the Philippines, 2023).

The park administration, which took up office in 2013, has been implementing a number of measures to combat illegal activities (UNESCO, 2014; UNESCO, 2015). In response to serious issues with land claims and illegal land sales, agricultural expansion and development, a new cadastral survey was initiated, and a Survey and Registration of Protected Area Occupants (SRPAO) was conducted in April 2014 (UNESCO, 2014; IUCN, 2015; UNESCO, 2015). To further clarify land use, delineation of zones within the World Heritage site is currently underway, and assessments of socioeconomic indicators using SEAMS (Economic Assessment Monitoring System) have been updated in the four barangays/villages within the site to determine the extent of users and utilization of resources within the site (IUCN Consultation, 2020b). However, it has been reported that areas continue to be titled to corporations and that in 2020, residents and land speculators have started to encroach on the forest areas (LGA report, 2020).

Plastic pollution has become an emerging threat to the Philippines, especially in Palawan (Sajorne et al., 2021). Studies investigating macro- and microplastic litter along the coasts of Palawan Island, including Puerto-Princesa Subterranean River National Park, have found high level of plastic pollution (Sajorne et al., 2021, 2022). Collected plastic were mostly fishing line nylon, food packaging and plastic fragments, while polymer types of mainly polyethylene terephthalate (PET) and polypropylene (PP) were found in the beach sediment. While the west coast of Palawan Island showed significantly lower plastic pollution than the east coast, plastic pollution represents a significant issue for the site ecology and biodiversity. Proper strategy, implementation of existing laws, and community participation are needed to address this problem. Local and national government units should intensify solid waste management and educate the public on plastic pollution’s ill effects.

Before Super Typhoon Rai, total forest in the park in 2021 was 16,674 hectares (79.2% of the total land area of the park). The Super Typhoon has damaged 9,619.34 hectares (57.69%) forests and 27.52 hectares (73%) of mangroves. Seventy-three percent (or 6,993 hectares) of the damaged forest were attributed to fallen or uprooted trees whilst 27% (or 2,627) were defoliated forests.
The climate-induced disaster has had a profound impact on the OUV especially for the indicator species within the park. For example, there has been a dramatic contraction, fragmentaion, and diminishing of the quality/suitability of the area of habitat of the Palawan hornbill (Anthracoceros marchei), Palawan peacock pheasant (Polyplectron napoleonis) and Busuanga wart frog (Limnonectes acanthi)- across the park. The species’ long-term survival are greatly compromised as this may contribute to isolation from the rest of the island.
Livelihood of indigenous peoples are also compromised because of the massive land cover change. Rattan and almasiga resin (both coming from forests) are potentially affected as the areas of habitat have been reduced significantly that might lead to reduced harvest (Mallari et al 2023).