Reassessment of Semecarpus calcicola
Kochummen - a narrow range endemic tree from
Sabah, Malaysia
Sandy T.L. Tsen , Loke Thian Yew , Aida Nabihah M Khatta , Normah Awang Besar , Zaleha Aziz ,
Richard B Sebastian , Syahrir Mhd Hatta , Suzika Juiling , Eyen Khoo , Sasikumar Tanggaraju ,
Kaden D Ashdown , Hoo Pui Kiat , Rimi Repin , Floriosha Landa , Colin R Maycock
‡ Forest Research Center, Sabah Forestry Department, Sandakan, Malaysia
§ Faculty of Tropical Forestry, Universiti Malaysia Sabah, Kota Kinabalu, Malaysia
| Faculty of Science and Natural Resources, Universiti Malaysia Sabah, Kota Kinabalu, Malaysia
¶ Forest Research Center, Sabah Foresty Department, Sandakan, Malaysia
# Oregon State University, Oregon, United States of America
¤ Sabah Parks, Kota Kinabalu, Malaysia
Corresponding author: Colin R Maycock ([email protected])
Abstract
Background
Desk-top based IUCN Red List assessment are an important first step in the conservation
of tropical trees, as they can serve as a guide for conservation action. However, field
validation is required to ensure that the limited resources available for plant conservation in
the tropics are being used effectively. The aim of this study is to conduct a field validation
of Semecarpus calcicola, a narrow range endemic tree from Sabah, Malaysia. S. calcicola
was previously known only from the type specimen collected in 1979 from Pulau
Mantanani Besar, Sabah, Malaysia. In a desk top assessment conducted in 2019, the
species was assessed as Vulnerable D2 due to a restricted range and possible threats
from land use change and natural disasters (Damit et al. 2019). During the Pulau
Mantanani Scientific Expedition in August 2019 and September 2020, surveys were carried
out on the three islands that comprise the Mantanani Islands group. Transect surveys and
plots were established to obtain information on the extent of occurrence (EOO), area of
occupancy (AOO) and an estimate of the number of mature individuals. We also assessed
the immediate and potential threats to the species.
New information
In this paper, we present new occurrences for Semecarpus calcicola, extending its
geographic range to a new island (Pulau Mantanani Kecil), and to a new substrate type
‡,§ § § § |
§ § § ¶ §
# § ¤ | §
©.
(calcareous sand deposits). We determined a revised area of occupancy (AOO) and extent
of occurrence (EOO) of 16 km for the species, and estimated the total number of mature
individuals to be below 1000 individuals. The largest subpopulation is located on Pulau
Mantanani Besar, and accounts for more than 90% of the mature individuals. Habitat loss
and degradation due to clearing of the low-lying areas for resort development and small-
scale agriculture on the limestone hills are the major threats to the population on Pulau
Mantanani Besar. While the population on Pulau Mantanni Kecil is within a gazetted
Bird Santuary, there was evidence of past small-scale agriculture. Based on these
threats, 3 locations were defined and the species reassessed as Endangered
B1ab(i,ii,iii,iv,v)+B2ab(i,ii,iii,iv,v); C2a(i,ii).
Introduction
The Post-2020 Global Biodiversity Framework calls for a reduction in the number of
threatened species and an increase in the abundance of species by 2050 (Secretariat of
the Convention on Biological Diversity 2020). While there is debate on the wording of this
goal and how it will be achieved (Williams et al. 2020), it dictates the need for accurate
assessments of the conservation status of the flora and fauna. The IUCN Red List of
Threatened Species is the primary sources of this information (Rodrigues et al. 2006). The
Red List is a useful tool for conservation planning as it allows for the identification of
species most at risk of extinction and the prioritization of conservation efforts (Rondinini et
al. 2014, Betts et al. 2020). However, to maximise the benefit accrued; the
assessments need to accurately reflect the species threat status. Within most biodiversity-
rich tropical countries, Red List assessments are typically a desk-top analysis of the
available data with input from experts. While these assessments are a good starting point,
there is a need for field validation, especially for species with traits that make them more
prone to extinction (Nic Lughadha et al. 2020, Duncan et al. 2021). Species range is one of
the major contributors to extinction risk (O'Grady et al. 2004), with narrow range endemics
generally facing a greater risk of extinction, than more widely spread species (Nic
Lughadha et al. 2020).
In a recent assessment of the 289 tree species endemic to the Malaysian State of Sabah,
73 species were recorded from a single locality (Tsen et al, unpublished data). All of these
species either fell within a threat category (65 species) or were categorized as data
deficient (8 species), and represent high priority candidates for field validation (Brummitt et
al. 2015, Bland et al. 2017). In this paper, we present a field validation of Semecarpus
calcicola, a narrow range endemic known only from the type locality on Pulau Mantanani
Besar (Large Mantanani Island) in Sabah, Malaysia.
Methods
Surveys were conducted across Pulau Mantanani Besar, Pulau Mantanani Kecil (Small
Mantanani Island) and Pulau Lingisan during the Pulau Mantanani Scientific Expedition in
August 2019 and September 2020. We determined the species distribution by mapping
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individuals encountered along transects on the Island’s network of trails, the ridge tops of
the limestone hills and transects crossing the islands. The location of the individuals
encountered were recorded using a Garmin GPSMAP 64csx. The extent of occurrence and
area of occupancy were calculated from the GPS coordinates using Geospatial
Conservation Assessment Web Tool GeoCAT (Bachman et al. 2011). The AOO was
calculated using a 4 km grid cell. To estimate the number of mature individuals, we
combined the data from the surveys with plot-based sampling. The plot-based sampling
was restricted to a 26.5 ha area that covered the limestone hills and adjacent low-lying
areas of Pulau Mantanani Besar (Fig 1). This is the recorded habitat of Semecarpus
calcicola (Kochummen 1996) and our initial surveys in August 2019 indicated it had the
greatest abundance of Semecarpus calcicola. In this area, we installed twenty-six 400 m
plots at randomly selected coordinates. All Semecarpus calcicola were enumerated, and
inspected for signs of flowering or fruiting. From these observations, we obtained a
minimum flowering diameter of 9.8 cm dbh and classified all trees greater than that as
potential mature individuals. To estimate the number of mature individuals, we used the
direct counts from the transects (excluding those within the 26.5 ha sampling area) and
extrapolation from the twenty-six 400 m plots (Loke et al. unpublished data). The species
was assigned to a Red List category based on the EOO, AOO and the estimated number
of mature individuals following the guidelines for using the IUCN Red List Categories and
Criteria (IUCN Standards and Petitions Committee 2019).
Species Conservation Profile
Semecarpus calcicola Kochummen
Species information
Taxonomy
Kingdom Phylum Class Order Family
Plantae Tracheophyta Rosids Sapindales Anacardiaceae
Taxonomic notes
This species was described by K.M Kochummen in 1996 during his revision of the
Anacardiaceae for Tree Flora of Sabah and Sarawak. The species name was initially
published using a male suffix as Semecarpus calcicolus (Kochummen 1996) and the
species is currently listed under this name on the IUCN Red List (Damit et al. 2019).
However, it has been changed to the feminine form Semecarpus calcicola on the
International Plant Names Index (IPNI 2021), as tree names are typically treated as
feminine (Manara 1991). The type specimen was collected in 1979 by Dewol Sundaling
& Awang Rahman (SAN 90206, Holotype: SAN herbarium) from Pulau Mantanani Besar
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2
2
3
Map of records (image):
Map of records (Google Earth):
Basis of EOO and AOO:
Min Elevation/Depth (m):
Max Elevation/Depth (m):
near Kota Belud, Sabah, Malaysia (Kochummen 1996). Kochummen (1996) distinguished
this species from the morphological similar species S. angulatus and S. cupularis based on
the inflorescence and habitat preference. S. calcicola has an extra axillary inflorescence,
with the other species having either a terminal or axillary inflorescences. Furthermore, S.
calcicola appeared to be a limestone specialist, being restricted to limestone hills of Pulau
Mantanani Besar.
Region for assessment:
- Global
Reviewers
To be determined
Editor
To be determine
Geographic range
Biogeographic realm:
- Indomalayan
Countries:
- Malaysia
Fig. 1
Suppl. material 1
Observed
Basis (narrative)
The EOO and AOO is based on GPS coordinate taken during the Pulau Mantanani
Scientific Expedition in August 2019 and September 2020.
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4
EOO (km2):
Trend:
Causes ceased?:
Causes understood?:
Causes reversible?:
AOO (km2):
Trend:
Causes ceased?:
Causes understood?:
Causes reversible?:
Number of locations:
Range description
Semecarpus calcicola is a narrow range endemic tree restricted to the Mantanani Island
group. The species was originally collected from the limestone hills on Pulau Mantanani
Besar in 1979, since then no other collections were made. In the recent Pulau Mantanani
Scientific Expedition organized by Sabah Parks in 2019 and 2020, the species was
recorded from the small limestone hills of Pulau Mantanani Kecil and the calcareous sand
deposits on Pulau Mantanani Besar (Fig. 2).
Extent of occurrence
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Decline (observed)
Justification for trend
Pulau Mantanani Besar has experienced an approximate 46% loss in forest cover. Forest
cover loss is continuing as a result of tourism development and land use change.
No
Yes
No
Area of occupancy
16
Decline (observed)
Justification for trend
Pulau Mantanani Besar has experienced an approximate 46% loss in forest cover. There is
a continued decline in forest cover on Palau Mantanani Besar and ongoing land use
change will result in habitat degradation.
No
Yes
No
Locations
3
5
Trend:
Number of individuals:
Trend:
Basis for decline:
Causes ceased?:
Causes understood?:
Causes reversible?:
Justification for number of locations
The number of locations was calculated to be three considering the main threats to the
species, namely small-holder cultivation and fire, resort development, small scale
harvesting and introduced ungulates.
Decline (observed)
Justification for trend
There is a continuous loss of forest cover and habitat degradation on Pulau Mantanani
Besar due to human activities.
Population
less than 1000 mature individuals
Decline (observed)
Justification for trend
Direct observation of changes in population and habitat extent and quality.
- (a) direct observation
- (c) a decline in area of occupancy, extent of occurrence and/or quality of habitat
No
Yes
No
Population Information (Narrative)
Fifty-four mature individuals have been located to date, of which 90% are on Pulau
Mantanani Besar. However, based on extrapolation from twenty-six 400 m plots the
estimated population on Pulau Mantanani Besar is between 509 and 764 mature
individuals (Loke et al. unpublished data). Currently there is no control over resort
development and the increasing number of resorts being established threatens the
population in the low-lying areas. There is also evidence of small-scale harvesting of
mature individuals across Pulau Mantanani Besar and small holder cultivation on the
limestone hills of both islands (Fig. 3). Seedling recruitment was high immediately after
fruiting, however, there was evidence of high rates of seedling herbivore (Fig. 4).
Subpopulations
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6
Abundance largest subpopulation:
Number of subpopulations:
Trend:
Severe fragmentation?:
System:
Habitat specialist:
Trend in extent, area or quality?:
Habitat importance:
Habitats:
Habitat importance:
Habitats:
Habitat importance:
Habitats:
~90% of individuals are on Pulau Mantanani Besar
2
Stable
Yes
Justification for fragmentation
The two subpopulations are found on seperate islands.
Habitat
Terrestrial
Yes
Habitat (narrative)
The population is found on the limestone derived soils and calcareous sand deposits of
Pulau Mantanani Besar and Pulau Mantanani Kecil. Most of the individuals occur on the
Gomantong soil association found on the limestone hills in the eastern part of
Pulau Mantanani Besar and to a lesser extent on Pulau Mantanani Kecil. Scatter
individuals were encountered on the Usukan soil association of Pulau Mantanani Besar.
The population is primarily found in the undisturbed forests, although there are some
individuals within abandoned coconut plantations and smallholder farms.
Decline (observed)
Justification for trend
There is a continued loss of forest cover on Pulau Mantanani Besar.
Major Importance
- 1.6. Forest - Subtropical/Tropical Moist Lowland
Marginal
- 14.3. Artificial/Terrestrial - Plantations
Marginal
- 14.4. Artificial/Terrestrial - Rural Gardens
7
Generation length (yr):
Dependency of single sp?:
Threat type:
Threats:
Threat type:
Threats:
Threat type:
Threats:
Ecology
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No
Ecology and traits (narrative)
Semecarpus calcicola is a small tree that reaches a maximum of about 18 m in height and
30 cm dbh. While the species is encountered on both the calcareous sand deposits and
limestone derived soils, it shows a preference for the ridges of the limestone areas (Loke et
al. unpublished data). Fruiting was observed in August 2019 and September 2020, on
individuals greater than 10 cm dbh.
Threats
Past
- 1.3. Residential & commercial development - Tourism & recreation areas
- 2.1. Agriculture & aquaculture - Annual & perennial non-timber crops
Ongoing
- 1.3. Residential & commercial development - Tourism & recreation areas
- 2.1. Agriculture & aquaculture - Annual & perennial non-timber crops
- 2.3. Agriculture & aquaculture - Livestock farming & ranching
- 5.3. Biological resource use - Logging & wood harvesting
Future
- 11.2. Climate change & severe weather - Droughts
- 11.4. Climate change & severe weather - Storms & flooding
Justification for threats
The species is threatened by habitat loss On Pulau Mantanani Besar, by the clearing of the
coastal plains for resort development and small-scale agriculture on the limestone hills.
Small-scale timber harvesting was also observed on this island. During the Pulau
Mantanani Scientific Expedition we observed abundant recruitment, however, almost all of
the recruits showed extensive herbivory damage (Fig. 4). The two likely candidates for this
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Conservation action type:
Conservation actions:
Conservation action type:
Conservation actions:
Use type:
Use and trade:
Ecosystem service type:
Research needed:
are the introduced domestic cattle or the terrestrial hermit crabs (Fig. 5). Further work is
required to determine the extent that this herbivory plays on seedling dynamics.
Conservation
Needed
- 1.1. Land/water protection - Site/area protection
- 2.1. Land/water management - Site/area management
- 3.4. Species management - Ex-situ conservation
- 4.3. Education & awareness - Awareness & communications
In Place
- 1.1. Land/water protection - Site/area protection
- 3.4. Species management - Ex-situ conservation
Justification for conservation actions
Currently only the small population on Pulau Mantanani Kecil has formal protection. Pulau
Mantanani Kecil is designated a Bird Sanctuary under the Sabah Land Ordinance 1960
(REF). There is a need to work with the local communities and resort owners to protect the
population on Pulau Mantanani Besar. During the Pulau Mantanani Scientific Expedition
seeds were collected from beneath four mother trees on Pulau Mantanani Besar, and a
small ex situ population has been established in the nurseries of the Faculty of Tropical
Forestry, Universiti Malaysia Sabah and the Forest Research Center, Sabah Forestry
Department. These seedlings need to be planted into suitable protected sites (Fig. 6)
Other
National
- 9. Construction or structural materials
Justification for use and trade
There is small scale local harvesting of this species for outdoor construction.
Less important
- 1.1. Research - Taxonomy
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- 1.2. Research - Population size, distribution & trends
- 1.3. Research - Life history & ecology
- 1.5. Research - Threats
- 2.2. Conservation Planning - Area-based Management Plan
- 3.1. Monitoring - Population trends
Justification for research needed
Semecarpus calcicola was described by Kochummen (1996) based on the morphological
characteristic of a single specimen, phylogenetic studies should be conducted to
validate this species. Further work is required to improve the estimates of population size
and population trend, particularly for the population on Pulau Mantanani Besar that faces
multiple threats. There is a need to work with the local community and resort owners to
develop a conservation management plan for this species, as continued resort
development, harvesting of mature individuals and clearing for small-scale agriculture
threatens this species.
Conclusion
Accurate assessment of the conservation status of species is crucial to facilitate
conservation actions and address the targets set in the Post 2020 Global Biodiversity
Framework. Within biodiversity-rich countries, the data on which to base these
assessments is sorely lacking for most plants and most assessments are based on a desk
review of past collection records (Prance et al. 2000). One of the shortfalls of relying on
past records is that there is the possibility that the threat category for the species will be
misassigned. Despite that, desktop assessments are a useful starting point to generate
a short list of candidate species for field validation. While field validation is both costly and
time-consuming it is essential to confirm that the status assigned accurately portrays the
situation on the ground and yields information that enable the development of species-
specific conservation actions. In the case of Semecarpus calcicola, the action
required involves a strengthening of existing protection on Pulau Mantanani Kecil, the
development of effective in situ conservation measures for the population on Pulau
Mantanani Besar and the establishment of a genetically diverse ex situ collection.
Acknowledgements
This work was conducted as part of Pulau Mantanani Expeditions organised by Sabah
Parks, we thank the director of Sabah Parks and staff for their support. We appreciate the
financial support provided by Universiti Malaysia Sabah through research grant
SDK0055-2018: Propagation and Conservation of Selected Threatened and Endangered
Species in Sabah.
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Figure 1.
Map showing Pulau Mantanai and locations of Semecarpus calcicola
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Figure 2.
A new record of Semecarpus calcicola from the calcareous sand deposits of Pulau Mantanani
Besar.
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Figure 3.
Evidence of small-scale agriculture on Pulau Mantanani Kecil
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Figure 4.
New recruit of Semecarpus calcicola showing herbivory.
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Figure 5.
Terrestrial hermit crab (Coenobita sp.) on a Semecarpus calcicola seedling.
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Figure 6.
Semecarpus calcicola seedling ready for planting at the Forest Research Centre, Sabah
Forestry Department.
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Brief description:
Supplementary material
Suppl. material 1: Fig S1. Distribution of Semecarpus calcicola and GeoCAT analysis
Authors: Tsen et al.
Data type: occurrences
The output from GeoCAT showing the AOO, EOO and distribution of
Semecarpus calcicola across the Pulau Mantanani island chain.
Download file (477.25 kb)
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