Abstract:
Marine mollusks are among the most diverse and ecologically important groups in coastal
ecosystems, yet patterns of diversity and distribution among islands remain poorly understood.
In particular, species distribution and overlap between coastal localities in the Philippines remain
unexplored, despite the archipelagic country being recognised for its exceptional biodiversity.
This study uses a shell collection as an unconventional and non-invasive approach to
documenting mollusk diversity, offering insights into rare and uncommon species often overlooked
in conventional surveys and live sampling methods, through a comparative analysis of
three islands: Ormoc, Leyte; Punta Engaño, Cebu; and Nocnocan, Bohol. Results reveal distinct
biodiversity and low species overlap across the sites, with estimates of more than 60, 70,
and 30 identified species, respectively, highlighting the differences among island communities.
The one-way ANOVA showed a significant difference in diversity among sites (F=0.471,
p<0.05). Nocnocan exhibits the lowest species richness and abundance, but demonstrates high
evenness and a balanced species distribution, suggesting a stable yet constrained community
dynamic, potentially due to its smaller size, isolation, and status as a tourist area. Ormoc and
Punta Engaño displayed significantly higher species richness and abundance with Punta Engaño
recording the highest biodiversity metrics. This pattern shows how island attributes may influence
species diversity, highlighting the necessity for location-specific management approaches.
While shell collections can provide useful insights, it is important to acknowledge that selective
collection may influence results. Therefore, the value of shell collections may be used as a
complementary tool, and the method can be further enhanced when interpreted alongside data
from field sampling techniques, offering a more robust approach to documenting species and
balancing the accessibility and historical value of collections with the ecological accuracy of
direct sampling.
