Setting the Conservation Agenda for Globally Threatened Species: the Forest Dependent Bleeding-Heart Pigeons

The ‘bleeding heart’ of the endemic pigeon Gallicolumba sp. may what makes it a seemingly mesmerizing and mystic creature. Naturally shy and evasive, they are well-known for the vivid red patch on their breast that appears like a bleeding wound. Fruit-eating birds such as the bleeding-heart pigeons are known important ecosystem service providers in tropical forests as they facilitate pollination. Sadly, the five species of bleeding-heart pigeons are globally threatened: Luzon bleeding-heart (Near Threatened, IUCN Red List), Mindoro bleeding-heart (Critically Endangered), Mindanao bleeding-heart (Vulnerable), Sulu bleeding-heart (Critically Endangered), and Negros bleeding-heart (Critically Endangered). Very few sightings resulted in sparse information about the bleeding-heart pigeons.

Past studies on these species point to bleeding-hearts as excellent ambassador species for the highly threatened forest habitats in the Philippines. Population levels and ecological requirements of all these species are poorly known, which may have contributed to the impediment of the success of conservation management efforts. Obviously, how can we effectively manage something that we do not have an in-depth understanding?

THE GRANT

To obtain relevant information about the bleeding hearts, CCIPH through the Science and Exploration in Asia research grant of the National Geographic embarked on a mission to fully understand the Philippine bleeding-heart pigeons in 2016. This research specifically studied and explored specific habitat needs and response to changing environmental variables of three Gallicolumba species: G. platenae, G. criniger, and G. keayi.

Estimation of population size and local abundance was also conducted to determine the status of these species in the islands where serious habitat fragmentation has been observed in the last decade. Sites covered in this project were Mt. Siburan in Sablayan, Mindoro Island (for G. platenae), Balinsasayao Twin Lakes Natural Park in Sibulan (for G. keayi), Negros Occidental, Mt. Nacolod in Southern Leyte (for G. crinigera).

A combination of field assessment techniques was employed for the assessment of the species on each target site:

Phase 1. Predicting where they might be: Species Distribution Modeling.

Prior to the field survey, the research team performed species distribution modeling to predict areas containing high concentration and suitable habitats in the identified target site on each of the species. This hastened the process of identifying the focus areas for the search of the bleeding-hearts. Occurrence records (i.e. geographic coordinates) obtained in previous surveys and a set of interpolated environmental predictors from WorldClim database were used to generate the model.

Consultation meetings and courtesy calls were then conducted by the field team particularly in the host community with the objective of introducing the study.

Phase 2. Identifying “Sweet Spots”

This phase was done in two stages. First, Transects routes (a minimum of 15) were set and traversed on areas identified by the SDM. All species encountered whether seen or heard, and taking note of time elapsed from arrival at sampling point, were recorded within the eight-minute sampling time. Broad habitat/vegetation surveys were conducted using transect routes, established for bird census. Results of the transect walks and point counts will be analyzed to identify specific areas where encounter of the NHB is highest (sweet spot).

Second, a 1-km grid was set after the ‘sweet spots’ were identified. Bleeding-heart occurrence was recorded and mapped within the grid to determine occupancy of the species. Detailed habitat recordings were done to identify specific habitat covariates that influences or limits the species occupancy and survival envelope.

Simultaneous to this stage, an extensive socio-economic dataset was generated through key informant interviews and focused group discussions determining potential solutions with the community and possible involvement of local peoples to conserve the species and their habitats.

Phase 3. Data Analysis (Occupancy Modeling and Population Estimation)

After the completion of the field work, the team proceeded with data cleaning and analysis. Through the presence-absence data from the grid/transect data, occupancy modeling will be performed to determine the species’ population and its spatial-ecological requirement. The The team utilized PRESENCE software to generate single-season and multi-season occupancy models. Using the same software, the Royce-Nichols function was used to generate the population estimate of the species.

Phase 4. Field assessment report writing and Community Validation

After writing the report, the team conducted a community validation meeting with the key stakeholders to present and gather feedback of the results of the study. Stakeholder feedbacks were essential part of the finalization of the report which included recommendations and commitment/s on the implementation of specific actions leading towards the conservation of the species.

MOVING FORWARD: A COMMUNITY EFFORT

Together with the local community, stakeholders and conservation experts, CCI PH identified urgent actions that should be taken to save the bleeding heart pigeons:

Improve protected area management
Increase coverage and scope of existing protected areas
Address drivers of deforestation and degradation
Improve forest governance
Declaration of new protected areas; and
Address massive deforestation and degradation for all five islands

Furthermore, CCIPH envisions that this project will encourage authorities to support and utilize actual field data and robust science in crafting strategies and policies in environmental management. This will further advocate conservation efforts around ambassador species that are known and are popular locally, and thus can act as flagships for the rehabilitation of the rapidly diminishing forest habitat. CCIPH is hopeful that will result to improvements in local conditions for both people and biodiversity.