Journal of Threatened Taxa |
www.threatenedtaxa.org | 26 March 2022 | 14(3): 20713–20720
ISSN 0974-7907
(Online) | ISSN 0974-7893 (Print)
https://doi.org/10.11609/jott.7261.14.3.20713-20720
#7261 | Received 06
April 2021 | Finally accepted 08 March
2022
Habitat preference and population
density of threatened Visayan hornbills Penelopides
panini and Rhabdotorrhinus waldeni in the Philippines
Andrew Ross T. Reintar 1, Lisa J. Paguntalan
2, Philip Godfrey C. Jakosalem 3, Al
Christian D. Quidet 4, Dennis A. Warguez 5 & Emelyn Peñaranda 6
1,2,3 Philippines Biodiversity
Conservation Foundation, Inc., Door 1 Roma Apartments, 12th Street Lacson, Bacolod City, 6100 Negros Occidental, Philippines.
4,5 Department of Biological
Sciences, College of Science and Mathematics, Mindanao State University-Iligan
Institute of Technology, Andres Bonifacio Ave, Iligan City, 9200 Lanao del
Norte, Philippines.
6 Conservation and Development
Division, Department of Environment and Natural Resources - Region VI, DENR
Region VI, Pepita Aquino Street, Port Area, Iloilo City, 5000 Iloilo,
Philippines.
1 andrewrossreintar@philbio.org.ph
(corresponding author), 2 lisapaguntalan@philbio.org.ph, 3 godo.jakosalem@philbio.org.ph,
4 alchristianquidet20@gmail.com, 5 dennis.warguez@g.msuiit.edu.ph,
6 emelyn_penaranda@yahoo.com
Editor: Anonymity
requested. Date of
publication: 26 March 2022 (online & print)
Citation: Reintar,
A.R.T., L.J. Paguntalan, P.G.C. Jakosalem,
A.C.D. Quidet, D.A. Warguez
& E. Penaranda (2022). Habitat preference and
population density of threatened Visayan hornbills Penelopides
panini and Rhabdotorrhinus waldeni in the Philippines. Journal of Threatened Taxa 14(3): 20713–20720. https://doi.org/10.11609/jott.7261.14.3.20713-20720
Copyright: © Reintar
et al. 2022. Creative Commons Attribution
4.0 International License. JoTT allows unrestricted use, reproduction, and
distribution of this article in any medium by providing adequate credit to the
author(s) and the source of publication.
Funding: United Nations Development Programme (UNDP) through the UNDP – Biodiversity; Partnership Project; Biodiversity
Management Bureau (BMB); Global
Environment Facility (GEF); Local Government Unit of Culasi; Local Government Unit of Sebaste
Competing interests: The authors
declare no competing interests.
Author Details: Andrew
Ross T. Reintar - Filipino. An ornithologist
and the Field Operations Officer of Philippines Biodiversity Conservation
Foundation. Recently conducted a conservation project on the Critically
Endangered Cebu flowerpecker and is currently involved in Sulu hornbill and Tawi-tawi biodiversity conservation, working on population
and ecological study, education, capacity development and community-based
forest protection. Lisa J. Paguntalan - Filipino. An ornithologist and the
Executive Director of Philippines Biodiversity Conservation Foundation. She’s
been doing conservation work for more than two decades focusing on threatened
species and habitats in the Philippines. Currently overseeing the Sulu hornbill
and Tawi-tawi biodiversity conservation program of PhilBio and other core conservation programs. Philip
Godfrey C. Jakosalem - Filipino. Is an
ornithologist and the Field Operations Manager of Philippines Bioversity Conservation Foundation (PhilBio).
He’s been doing conservation work on for two decades, working on bird
conservation and ecology. Currently one of the lead of the Sulu hornbill and Tawi-tawi biodiversity conservation program and waterbirds research of PhilBio. Al
Christian D. Quidet - Filipino. Currently a
medical student of Xavier University in Mindanao. Previously involved in
biodiversity research during his undergraduate thesis with particular focus on
Visayan hornbills. Dennis A. Warguez - Filipino. An associate professor of
Mindanao State University-Iligan Institute of Technology, is currently enrolled
as a Ph.D. student at De La Salle University-Manila. He had recently conducted
herpetological surveys organized by Herp Watch Pilipinas
in Antique, Samal Island, Mt. Apo Protected Area, and
Mt. Hamiguitan Range Wildlife Sanctuary. Emelyn Peñaranda -
Filipino. Development Management Officer of the Department of Environment and
Natural Resources Region 6. She is now actively engaged in the implementation
of conservation and development programs and projects concerning protected areas, biodiversity, forest, coastal and marine and
urban ecosystems as well as climate change and gender and development.
Author
contributions: ARTR—Manuscript writing. Survey and
data gathering. Performed the analysis and map making of the study.
Conceptualization of the study. Arrangements and preparations of the survey
expedition. LJP—Manuscript writing and review. Conceptualization, development
and realization of the study and survey expedition. Fund sourcing for the
project. PGCJ—Conducted survey and data gathering. Conceptualization and
development of the study. ACDQ—Survey and data gathering. Conceptualization of
the study. DAW—Survey and data gathering. Conceptualization of the study.
Arrangements and preparations of the survey expedition. EP—Arrangements and
preparations of the survey expedition. Manuscript review.
Acknowledgements: We are grateful on the support
from several highly committed individuals and institutions, specifically, the
United Nations Development Programme - Global Environment Facility through the
Biodiversity Partnership Project of the Department of Environment and Natural
Resources - Biodiversity Management Bureau, William Oliver Student Research
Grant, Virginia Zoo and DENR Region 6. We thank CENR Officer Cynthia Blancia and CDS Chief Gloria Decena,
Director Mundita S. Lim, BPP Manager Jose Regunay, Former DENR-6 RD Jim Sampulna,
Former DENR-6 RTD Carlo Custodio, Melba Salditos, MSU-IIT Chancellor Sukarno Tanggol,
Mayor Jose Christopher Varona and Alma Lisay Sandig; to Mayor Jose
Jeffrey Lomugdang. To our field technicians: Pedro Villarta and Jaime Getaruelas;
volunteers: Ecel Mae Lagudas,
Erl Pfian Maglangit, Ronnie Jann Ian Mabitasan;
to our field guides: Junjun, Roland, Elliser, Pato, Edmund, Almond,
Renz, Jomari, Lito, Arnel, Ranti, Alex, Sonny,
Charlie, Sonny and Benjamin.
Abstract: The habitat preference and
population density of the Critically Endangered Rufous-headed Hornbill Rhabdotorrhinus waldeni
and Endangered Visayan Tarictic Hornbill Penelopides
panini were studied in the Central Panay Mountain range in Panay Island,
western Visayas. Point counts were established to
survey for hornbills and habitat variables were measured in a 30 x 30 m plot at
each point. P. panini was recorded in primary and secondary forest,
while records of R. waldeni were mostly in
primary forest, with only one record in secondary forest. Spearman’s rank order
correlation and stepwise multiple regression showed that R. waldeni is positively correlated to density of large
trees (>70cm DBH), with the Visayan Tarictic Hornbill showing moderate
correlation with density of medium-sized trees (31–70 cm DBH). Central Panay
Mountains is the largest remaining forests block in western Visayas.
It is the stronghold area of R. waldeni and
other western Visayas threatened species, supporting
the need to declare the site a protected area.
Keywords: Critically Endangered,
Endangered, Panay, Rufous-headed Hornbill, Tarictic Hornbill, western Visayas.
INTRODUCTION
There are 62 species of hornbills
in the world, of which 10 species and six subspecies are endemic to the
Philippines (Gonzalez et al. 2013; Poonswad et al.
2013). All Philippine hornbills occur in lowland forests below 1,200 m
(Gonzalez et al. 2013), but forest loss in the lowlands may have pushed species
to the upper limit of up to 1,500 m elevation (Poonswad
et al. 2013). Of the 10 species in the Philippines, two are classified as
Critically Endangered, two as Endangered, and six as Vulnerable (IUCN 2020).
The Ticao Hornbill Penelopides
panini ticaensis, subspecies of the Visayan
Tarictic Hornbill was declared Extinct (Poonswad et
al. 2013) because of habitat loss. The Rufous-headed Hornbill Rhabdotorrhinus waldeni
and P. panini are restricted-range species found only in the islands
of Negros and Panay in western Visayas, where they
inhabit lowland forest (Image 1 & 2). With continuing lowland forest
loss, populations have been assessed by BirdLife and
the International Union for the Conservation of Nature (IUCN) as decreasing. BirdLife International (2020) and the IUCN (2020) estimate
the Panay population at 1,800 individuals, with 1,200 mature individuals, and
declared the Negros population as possibly extinct.
Currently, only three protected
areas (PAs) exist in Panay: Northwest Panay Peninsula Protected Landscape, Sibalom Natural Park, and Bulabog-Putian
Natural Park. Despite ongoing conservation efforts, the largest remaining
forest and stronghold of hornbill populations is in the Central Panay
Mountains, and remains unprotected. This paper presents information on the
habitat, abundance and conservation status of P. panini and R. waldeni in CPM. Conservation initiatives primarily led
by local government units and Department of Environment and Natural Resources
(DENR) are also presented. This research was undertaken as part of the
Philippine Hornbills Conservation Programme of Philippines
Biodiversity Conservation Foundation Inc.
METHODS
Study area
The Central Panay Mountain (CPM)
refers to the chain of mountains that stretches and divides Panay Island into
four provinces: Iloilo, Antique, Aklan, and Capiz (Klop et al. 2000; Mallari et al. 2000). The mountainous
spine of CPM encompasses the largest forest area of montane and lowland
forests. Survey for hornbill population and habitat preference was conducted in
Mt. Camantra, Sebaste,
Antique from 25 July 2016 – 3 August 2016 and from 4–9 August 2016 for Mt. Igpako, Culasi in Central Panay
Mountains. At the onset of the field surveys, severe tropical storm Nida
affected the weather conditions in the country including Panay Island. Field
research was authorized by DENR Region VI through a gratuitous permit issued to
Philippines Biodiversity Conservation Foundation Inc. (PhilBio).
Mt. Camantra
(11.544778°N & 122.148408°E)
The Mt. Camantra
is located in the municipality of Sebaste (Figure 1)
with elevation range of 444–996 m. The primary forest covers steep ridges and
gullies. The average height of trees was 25 m and majority have more than 30 cm
diameter at breast height. Canopy cover ranges 60–100% forest cover. Thick and
tall undergrowth cover the trail and some areas were almost inaccessible with
fallen dead trees and decaying logs. Forest trails were hardly visible
indicating limited human-related activities. The secondary lowland forest
habitat (11.544139° N & 122.147083° E) was located at 419 m. Majority of
the trees have heights ranging 10–15 m with average diameter at breast height
of 30 cm (n= 41 plots). The trails were visible following rivers, streams, and
mountain ridges. The canopy cover ranged from 40–80 %. Abandoned agricultural
clearings and presence of pineapple and coconut plantations were observed in
the lower sections of the forests closer to the town and lower reaches of
rivers and streams.
Mt. Igpako
(11.466167°N & 122.1355°E)
The Mt. Igpako
site is located in the municipality of Culasi (Figure
1) with primary lowland forests reaching up to 631 m. The forest understory was
thick with Pandanus sp. and few climbing bamboo species. Large uprooted
trees from recent typhoons were encountered. Canopy cover ranges 60–90% with
patches of openings created from uprooted trees. In elevations above 900 m,
moss cover thickly covered the forest floor and barks of trees.
Hornbill distribution and
abundance: point-count sampling
Twenty-four-point count stations
were established and surveyed, 15 located in the primary lowland forests of Mt.
Camantra, Sebaste (5
points) and Mt. Igpako, Culasi
(10 points), and nine in the secondary lowland forest in Mt. Camantra, Sebaste. Each sampling
point was at least 250 m apart and the observation record bands are 100 m
radius. Bird observations were conducted from 0600 h to 1100 h. Two to three
observers recorded the distance of the hornbill from the center of the point
station as well as the number of individuals seen or heard. Distance of the
hornbill was recorded only through estimate. Observation per point was around
10 minutes. 8 x 42 and 10 x 42 roof-type binoculars were used during the
survey.
We identified forest type
following the definition from the Convention on Biological Diversity (CBD):
Primary forest is a forest that has never been logged and has developed
following natural disturbances and under natural processes. Secondary forest is
a forest that has been logged and has recovered naturally or artificially.
Habitat assessment
Twenty-four 30 x 30 m plots were
established in each of the 24 sampling points to determine habitat
characteristics (Table 1). Canopy cover was measured using an improvised densiometer, and a tape measure was used in acquiring
diameter at breast height (DBH). Understory cover percentage was measured
through visual estimate. Garmin GPS was used to measure elevation and
coordinates.
Data analyses
Hornbill density was acquired by
calculating the average number of hornbills per point and dividing it by the
total area sampled (3.14 hectares/point * number of point count stations)
(Raman & Mudappa 2003). Density and population
estimate using DISTANCE program was not used due to insufficient number of
encounters for both species of hornbill.
Mann-Whitney U-test was used to
compare the habitat variables between primary and secondary forest. Spearman’s
rank-correlations and multiple linear regression (stepwise) were used to
identify relationship between habitat variables and hornbill abundance.
RESULTS
Hornbill distribution and records
We recorded a total of 12
detections (22 individuals) of P. panini and 31 detections (94
individuals) of R. waldeni. P. panini was
recorded four times in primary forest and eight times in secondary forest while
99% of the records of R. waldeni were in
primary forest. There were 13 R. waldeni positively
identified as female and 18 as males and the rest were heard in groups. The
highest number of individuals observed in a cluster was 25 (eight females, 13
males and four immature) while the average number of individuals encountered in
a flock was 10. In the case of P. panini, three were positively
identified as males and four were females.
We observed R. waldeni in secondary forests feeding on fruiting native
trees together with P. panini, Pink-bellied Imperial Pigeon Ducula poliocephala, Green
Imperial Pigeon Ducula aenea,
Philippine Cuckoo dove Macropygia tenuirostris and other fruit-eating species.
Hornbill habitat preference
The primary lowland and secondary
forests in CPM varied across sites. There were more large and tall trees in the
primary and secondary forests of Mt. Camantra in Sebaste than in Mt. Igpako in Culasi. We tested for significant differences between
primary and secondary forests using Mann-Whitney U-tests. Trees with a range of
16–20 m tall and trees with 31–70 and >70cm DBH varied significantly between
primary and secondary forests (Table 1; Figure 2). This difference influenced
the abundance of the hornbills. The R. waldeni
was significantly correlated to the density of trees with 31–70cm DBH (rs= 0.614, P= 0.001) and trees greater than 70cm
DBH (rs= 0.618, P= 0.001). This species
was recorded almost strictly to primary forest with only one record in
secondary forest. There was no significant correlation between habitat variable
and P. panini, abundance. P. panini was recorded in both primary
and secondary forest with most of the records in the latter.
Stepwise multiple regression
showed that P. panini abundance was positively correlated with
understory cover (R2= 0.127, P= 0.049, Table 3) while the R. waldeni, abundance was positively related with presence
of trees with >70cm DBH (adjusted R2= 0.340, P= 0.002).
DISCUSSION
The forests in Sebaste and Culasi still contain
significant lowland tropical rainforests. Both hornbills were encountered in
primary and secondary lowland forest. Undisturbed forests with tall and large
trees were positively correlated with the occurrence of the hornbill. The CPM
remains as the main population stronghold of the Critically Endangered R. waldeni as it retains the largest lowland tropical
rainforest on the island.
In 2017, the Haribon
Foundation estimated 2,960–3,700 individuals remaining in Panay (Condeno 2018), slightly higher than the 2014 estimates of
2,880–3,600 (Quimpo et al. 2014). Based on the
estimates, R. waldeni appears to have
maintained its population since 2007 (Alabado et al.
2009; Quimpo et al. 2014; Condeno
2018). BirdLife International (2016) estimated
population of R. waldeni at 1,000–2,499 mature
individuals with total number of individuals at 1,500–4,000. From this study,
we acquired a density of 0.2 individuals/hectare (20 individuals/km2) for the P.
panini and 0.47 individuals/hectare (47 individuals/km2) for the R. waldeni. This is a crude estimate from our field
observations and basic density calculation from number of recorded hornbills
and the sampled area and accuracy can be improved with more data particularly
on adjacent forest areas and to run the analysis in the DISTANCE program.
Mynott et al. in 2021 estimated the
population density of P. panini in Northwest Panay Peninsula Natural
Park (NWPPNP) through DISTANCE analysis to be at 17.8 individuals/km2
(0.178 individuals/ha) in primary forests and 3.7 individuals/km2
(0.037 individuals/ha). Though we were not able the acquire density estimates
using DISTANCE analysis and per forest type our crude estimate of 20
individuals/km2 (0.2 individuals/ha) was close with their primary
forest density estimate. In terms of encounters between forest types, we
detected the P. panini more in the secondary forest (8 encounters) than
the primary forest (4 encounters) while Mynott et al.
in 2021 encountered more P. panini in primary forest (31 encounters)
than in secondary forest (12 encounters). We suspect that this was the case for
the sites we surveyed in CPM because of the presence of R. waldeni, which we observed to be more abundant and
dominant particularly in the primary forests.
R. waldeni is almost certainly
extirpated in NWPPNP (Birdlife International 2022) and its presence needs to be
confirmed. With that, there is lesser competition for space and resources for
the P. panini in NWPPNP, most significantly in the primary forests. Though the two species of hornbills co-exist
and form flocks, there will be competition for nesting trees during breeding
season. The P. panini having a broader habitat preference, requiring
less pristine conditions than the R. waldeni,
were able to occupy the secondary forests if competition for resources ensues.
P. panini shows preference to areas with
medium-sized trees (30–70 cm DBH) which could be one of their minimum
requirement for nesting. This was similar to the results of Klop
et al. (2000) in their study of nest site characteristics, where the mean DBH
of nesting trees of P. panini was 34 cm. Klop
et al. (2000) only measured one nesting tree of R. waldeni
that was 90 cm. These results indicate that P. panini has a wider
range of habitat preference, and thus it is able to survive in secondary
forests and tolerate some level of disturbance. R. waldeni
on the other hand has a narrow preferred habitat range, requiring large
trees and undisturbed forests. Among the sites in Panay, CPM holds the largest
lowland forest cover in Panay followed by Northwest Panay Peninsula Protected
Landscape and Sibalom Natural Park.
Hornbill distribution
The past distribution of P. p.
panini was on Negros, Panay, Masbate, Sicogon,
Pan de Azucar and Guimaras
Islands. However, it is now extinct on the latter three and only survives in
small forest fragments on Negros and Panay (Poonswad
et al. 2013; Paguntalan et al. 2002, 2004). It
is uncertain if populations still remain on Masbate Island although locals have
reported the presence of the species in small forest fragments in Milagros and Mobo watershed in 2013. The loss of forests, combined with
hunting, have threatened the survival of the bird in the wild, exemplified by
the extinction of Ticao hornbill (Klop
et al. 2000; Poonswad et al. 2013).
R. waldeni
was known to
occur on Negros, Panay and Guimaras Island. It is now
extinct on Guimaras and survives in lowland forests
in Negros and Panay. There were very few records of the species in the last 30
years in Negros (Poonswad et al. 2013). We
have encountered two females and two males in Northern Negros Natural Park on
20 March 2013 and two females and five males in 16 February 2017. A lone female
was observed from the viewing deck in Balinsasayao
Twin Lakes Natural Park last on 22 June 2017 while a group of three individuals
composed of one female and two males were seen on 19 August 2019.
The two threatened hornbills are
reported to occur in at least five Protected Areas in Panay and Negros. Of the
five, two are in Panay (Sibalom Natural Park and
Northwest Panay Peninsula Protected Landscape) and three in Negros (Northern
Negros Natural Park, Mt. Kanlaon Natural Park and Balinsasayao Twin Lakes Natural Park) (Table 4). Two of the
significant forest blocks (Cuernos de Negros Mountain
Range in Negros and the Central Panay Mountain Range in Panay) remain
unprotected. With the known forest areas where the R. waldeni
exists, of which there are few, the CPM is the stronghold and the most
important sanctuary for the species.
Threats
The primary lowland forests in Sebaste and Culasi are still
relatively undisturbed. Part of the reason for this is the topography of the
area. The forests are found on steep mountain ridges and gullies that are
difficult to access. Trails follow the rivers and streams and bisect steep
slopes to reach the mountain ridges. The lower reaches and areas close to the
villages showed evidence of disturbances while the forest interior remained
relatively pristine. As one moves farther away from the villages and rivers,
less disturbance in forests was encountered.
In areas close to the villages
and towns, habitat destruction and hunting remain as the main threats to
hornbill populations. Large trees were observed being selectively logged for
timber needed to make boats and houses or sold as lumber in the nearby town.
Clearings were then planted with subsistence crops. Locals were also reportedly
using marble guns for hunting birds and other animals for protein and for
sport.
During the survey, two of the six
known nesting trees of R. waldeni in Mt. Camantra were uprooted by previous typhoons. We also
recorded two additional nesting holes suspected to be that of R. waldeni based on the size of the tree, location and
size of the nesting hole and the larger seeds found at the base of the tree
trunk directly below the nest hole. Locals have also reported this nest as that
of R. waldeni.
Conservation efforts
The national threatened status of
R. waldeni remained at Critically Endangered
status, but P. panini was changed from Endangered to Critically
Endangered status in the recent revision of the National List of Threatened
Fauna and their categories in the Department Administrative Order 2019 – 19
(BMB DENR 2020).
The enactment of the Expanded
National Integrated Protected Areas System (ENIPAS) Act of the Philippines
effectively legislated into law the declaration of two Protected Areas in
Negros (Balinsasayao Twin Lakes Natural Park and
Northern Negros Natural Park) and two in Panay (Northwest Panay Peninsula
Protected Landscape and Sibalom Natural Park). Mt. Kanlaon Natural Park has its own Republic Act declaring it
as a protected area in 2002.
The DENR Region VI initiated the
protected area suitability assessment (PASA) last December 2020–January 2021 as
the first step in declaring Central Panay Mountain Range as a protected area.
This was in response to the resolution passed by the Regional Development
Council of Region VI in 2018. There were several attempts in the past to
declare the CPMR as a nationally declared protected area, but only local
legislations were enacted.
MANAGEMENT RECOMMENDATIONS
Declaration of Central Panay Mountains
as Protected Area – The Regional Development Council of Region VI and
the Department of Environment and Natural Resources (DENR) Region VI had
initiated the process of declaring Central Panay Mountains as a protected area
last October 2018. The move to declare CPM as PA started in the early 1990s and
with millions of funds poured in the last two decades, this has remained a
suggestion. Local Government Units (LGU) of all four provinces should seriously
investigate securing the very mountains that provided its life support system:
freshwater.
Collaboration with LGUs and
stakeholders in monitoring protected areas – average annual national budget
allocations for monitoring PAs is US $581 while class A local government units
have annual funds of at least US $19,380 for environmental programs including
monitoring PAs. The Protected Areas Management Board of each PA, DENR and LGU
within Key Biodiversity Areas (KBAs) should institutionalize the conduct of
synchronized bio-monitoring and hornbill count in each Protected Area and KBA
using improved line-point and DISTANCE analysis.
Surveys on threatened hornbills
of western Visayas – Surveys are needed in the
other identified forests patches, e.g., Northwest Panay Peninsula Protected
Landscape, Sibalom Natural Park, Cuernos
de Negros Mountain Range, Sta. Catalina forest, Masbate Island, to determine
the presence of surviving populations.
Table 1. Mean values and
Mann-Whitney U-test results of habitat variables between primary and secondary
forest.
Habitat variable |
Primary forest |
Secondary forest |
U |
p |
Elevation |
646.7 |
266.8 |
135 |
0.000 |
Density of 10–15 m tall trees
(no./ha) |
369 |
257 |
|
|
Density of 16–20 m tall trees
(no./ha) |
126 |
71 |
103 |
0.035 |
Density of >20 m tall trees
(no./ha) |
45 |
33 |
|
|
Canopy cover (%) |
67.3 |
70 |
|
|
Understory cover (%) |
67.3 |
53.5 |
|
|
Density of trees with 10–30 cm
DBH (no./ha) |
291 |
272 |
|
|
Density of trees with 31–70 cm
DBH (no./ha) |
200 |
87 |
116.5 |
0.007 |
Density of trees with >70 cm
DBH (no./ha) |
24 |
0 |
112.5 |
0.005 |
Standing dead tree (no./ha) |
20 |
6.3 |
|
|
Table 2. Stepwise multiple
regression analysis of hornbill abundance with significant habitat variables
and values.
Species |
Variables |
Standard error (SE) |
Standardized coefficient Beta |
p |
Visayan Tarictic Hornbill |
Constant |
1.077 |
|
0.296 |
|
Understory cover |
0.017 |
0.406 |
0.049 |
Rufous-headed Hornbill |
Constant |
0.596 |
|
0.233 |
|
Density of trees with >70 cm
DBH |
0.331 |
0.607 |
0.002 |
Table 3. Estimates of forest in
Panay and Negros island.
Name of area |
Size (ha) |
Estimated forest cover |
Forest <1,200 m (ha) |
Northwest Panay Peninsula Protected
Landscape |
12,009 |
8,000 |
5,000 |
Central Panay Mountain Range |
105,200 |
105,200 |
30,049 |
Sibalom Natural Park |
5,511.47 |
672 |
672 |
Northern Negros Natural Park |
70,826.16 |
24,000 |
~10,000 |
Mt. Kanlaon
Natural Park |
24,388 |
8,000 |
~2,500 |
Balinsasayao Twin Lakes Natural Park |
8,016.05 |
3,000 |
~2,500 |
Cuernos de Negros Mountains |
4,096 |
2,000 |
~500 |
Source: Condeno (2018); Schade
(2018); NAMRIA (2010); DENR FMB (2013); de Alban et al. (2004); Quimpo et al. (2014); PBCFI – BMB (2019).
For figures &
images - - click here
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