UP biologists uncover the promise of “surrogate species” to PH biodiversity

In a country where natural resources were once rich and fertile, the odds for species trampling at the brink of endangerment are soaring beyond what is thinkable. 

As the road toward extinction sets clear, it all comes back to the methods of human practice and how to address this dilemma better, deciding how much of Earth’s living heritage must be understood, protected, and preserved. Facing the urgency of time and limited resources, scientists turn to surrogates—species that can stand in for the many others that cannot be studied yet.

A 2025 study by Jay Fidelino, Rio Renato Constantino, and Dr. Mariano Roy Duya from the University of the Philippines Institute of Biology dives into this case. By examining relationships among amphibians, reptiles, birds, and mammals across the country’s Key Biodiversity Areas (KBAs), the researchers probe whether these surrogates can serve as a baseline for biodiversity monitoring and conservation planning.

The needs of surrogates

The Philippines, a megadiverse nation yet so vulnerable, is highly susceptible to the threats brought by deforestation, habitat fragmentation, and urban expansion. Decades of poor management, deforestation, urbanization, and pollution have pushed Philippine ecosystems to the edge. 

A 2021 study cited how urbanization in Southeast Asian countries, such as the Philippines, leads biodiversity hotspots to become susceptible to ecological imbalance. Habitats such as mangroves, coral reefs, and forests continue to experience these severe threats. 

With the country having already lost about 93% of its primary forests, this delivers concerns like food and water insecurity, the displacement of indigenous peoples, high mortality rates due to calamities, and biodiversity loss. Hence, profiling organisms is a challenge.

With that, surrogates serve as stand-ins in estimating overall biodiversity status while also assessing how ecosystems respond to environmental pressures or restoration efforts, guiding which areas or actions to be prioritized.

By studying one group, scientists can infer the distribution, richness, and fitness of other species. It is pragmatic, allowing conservation efforts to move forward despite the limits of data and time.

Patterns across KBAs

The UP researchers analyzed over a thousand species, including amphibians, reptiles, birds, and mammals, distributed across terrestrial and terrestrial-marine KBAs. These areas serve as the nation’s frontier for many endemic and threatened species. 

The question was simple: do these groups exhibit similar patterns of diversity?

According to the study, its findings indeed showed congruence among taxa. Reptiles, in particular, exhibited strong alignment with their distribution patterns. Mammals followed next, then amphibians, and finally birds. 

This congruence indicated that despite their ecological differences, they continue to share similar responses to the conditions of their environment and habitat.

Rethinking surrogacy to the endemics and threats

Despite promising data, certain regions of the study showed discrepancies. Where one taxon flourished, another faltered. These variations stress the complexity of interactions as shaped by habitat and biogeography. 

Scenes changed when diverted to threatened species. Unlike endemics, their distributions were far less consistent. Drawn by differences in several factors, this inconsistency challenges the use of threatened species as a basis for prioritization, which prompts a more careful approach to threatened-species-based surrogacy.

Beyond richness, the researchers probed deeper into the makeup of biodiversity—specifically the proportions of endemic and threatened species. Endemic species, confined to the Philippines and nowhere else, exhibited relatively consistent distribution patterns across taxa. This congruence supports the use of endemics as reliable indicators of regional biodiversity value.

Furthermore, depending on surrogates at all times comes at a cost. While surrogates provide valuable findings, they are not a one-size-fits-all solution for biodiversity planning. Ecosystems vary across regions, and a surrogate that effectively represents biodiversity in one area may not fully capture the ecological dynamics in another. Not all the time, the assumption that one taxon’s distribution mirrors another is always accurate.

In the reality of rising biodiversity loss, surrogates offer both a lifeline and a limitation. The work of the scientists demonstrates that surrogate taxa can elucidate patterns that are hidden. Yet their findings also remind us that biodiversity cannot be distilled to a single measure. The future of Philippine ecology still depends on the balance between efficiency and accuracy, and it is only through continued sources for study that conservation can take root.