Plant Diversity and Status in the Northern Landscape of Mt. Malindang Range and Environs, Misamis Occidental, Philippines
Corazon G. Alava, Ph. D.
The high biodiversity in the Philippines is attributed to a large number of islands and the presence of many high mountains. Mindanao, the second largest island in the Philippine archipelago, supports a wide variety of plants. However, like the rest of the archipelago, the area covered by natural forests is rapidly decreasing with only 29% remaining, most of which are located in upland ranges.
Mt. Malindang Range Natural Park, located in the provinces of Misamis Occidental, Zamboanga del Sur, is the only representative natural forest in Zamboanga Peninsula Biogeographic Zone (Myers 1988). However, it is one of the upland ranges where biodiversity has been severely threatened due to the conversion of the forest to agricultural land and human settlements. The commercial and social demand for the biological resources has resulted in high rates of biodiversity loss. Economically important and endemic species are threatened by habitat loss and nonsustainable utilization. Mt. Malindang has become one of the “hotspots” in the Philippines that has to be highly prioritized for protection and conservation (Ong et al. 2002).
The study was conducted to generate knowledge on the critical flora resources of Mt. Malindang. Through the participatory approach, it intended to provide a better understanding of plant species diversity and availability s that resources can be shared and managed effectively.
Review of Related Literature
Ecosystem and Species Diversity
Mindanao has an estimated forest cover of 30,960 sq km, which is 24.55% of its total land area of 126,092 sq km.( 10,060, 900 hectares). It has a wide spectrum of ecological diversity, namely: beach forest, limestone or karst forest, forest over ultrabasic or ultramafic soils, lowland dipterocarp forest, montane and mossy forests and grassland vegetation (Conservation International 2002).
The flora of Mindanao is largely allied to that of the Papuasian-Australasian and t0 a lesser degree, to that of the Bornean via the Basilan-Sulu-Tawi-tawi island arch and Zamboanga. The Papuasian-Australasian affinity is best exemplified by the present distribution range of the following genera: Eucalyptus (Myrtaceae), Discocalyx (Myrsinaceae), Heterospathe (Arecaceae) and Sararanga ((Pandanaceae) (Fernando 2001); Gruezo and Zamora 200). On the other hand, the Bornean affinity is demonstrated by the distribution ranges of Salaca and Plectocomia (Fernando 2001); Ashton 1993).
Plant communities may be considered subdivisions of a vegetation cover. Likewise, vegetation consists of a mosaic of plant communities in a terrestrial landscape. Wherever the cover shows more or less obvious spatial changes, one may distinguish a different community. These changes in spacing and height of plants , changes in life forms of plants, which in turn may correspond to spatial changes in the environment(Muller and Heinz 1974).
Different plant communities reflect the prevalence of different abiotic factors such as climate, relief ( altitude and aspect). Soil , water conditions, and eventually land use. The close relationship of a plant community to the site on which it occurs led to the introduction of the term ecosystem. The vegetation specialist maps plant communities as to their location, extent and distribution. Many vegetation ecologists assume that the plants in a community are interdependent and that communities are integrated entities.
There were 12,000 species f plants credited to the Philippines, consisting of 8,000 flowering plants ( Madulid 1995), 1,023 ferns (Amoroso 1997), 77 fern allies and 3,000 nonvascular plants( Zamora 1991). Out of the 12,000 Philippines plant species listed officially as endangered (Tan et al. 1986; Gruezo 1990). Furthermore, Madulid (1991) reported that of the 8,000 species of flowering plants, 23 genera and about 3,500 species were endemic to the country.
Among the flowering plant families, the Orchidaceae, Rubiaceae, Myrtaceae, Euphorbiaceae, Annonaceae and Melastomataceae had the greatest number of endemic species, while Gramineae, Liliaceae. Ulmaceae, Leguminosae and Rutaceae had lower endemism. The gymnosperms were poorly represented with only 33 species and 18% endemism while the pteridophytes had 30% endemism (Zamora and Co 1986; Amoroso 1997).
Salgado (1990) reprted 958 species of ferns belonging to 151 genera in 31 families. In Mindanao, a total of 574 species were recorded. In Mt. Kitanglad alone, there were 410 species ( Amoroso et al. 1996). Mindano is also rich in fern allies. Of the 79 species of fern allies in the Philippines, 68 are found in Mindanao ( Amoroso et al. 2001).
The flora of the Philippines is rich in endemic forms. An endemic plant is presumably evolved locally and therefore constitutes part of the unique plant life of the country. Zamora and Co ( 1986) has reported that the 930 species of Phlippine ferns, 278 are endemic species while 6 ( Psomiocrpa, Thayeria, Tectaridium, Podosorus, Nannothelypsteris and Copelandiopteris) are endemic genera. It should be noted that despite the high specific endemism of the local flora ( about 33%), generic and high specific endemism can be explained by the geologic history of the country. One explanation is the evidence that the archipelago has not been separated long enough from the neighboring islands to develp many endemic genera. Because a genus is a more distinct entity, it requires a longer period to evolve ( Zamora and Co 1986).
Inventory and assessment of plant species are aimed to measure and quantify biodiversity. They describe species richness and abundance ( Gruezo 1997; Amoroso et al. 1996; Polacks 2000; Arances et al. 2004), a number of ndangered, rare and extinct species ( Cali et al. 1999; Arances et al. 2004; Tan et al. 1986; Gruezo 1990), species functions and relations (Gruezo and Gonzales 1997), biodiversity indicators (Noss 1990; Reid 1994; Ticsay-Ruscoe 1997; Gruezo and Gonzales 1997), species distribution (Madulid 1995; Gonzales and Dans 1997; Lubos 2000), species uses and ecological importance ( Saniano 1981; Agbayani 1996; Burton 1996; Arances et al. 2004) and enumeration and status of certain groups of spcies ( Rojo 1996 and 1999; Pipoly amd Madulid 1996; Amoroso 1997; Gonzales 2000; Amoroso et al. 2000; Alava 2000) among others.
Statement of Problem and Objectives
The study was conducted to inventory and assess the plant resources in the Mt. Malindang Natural Park. Specifically , the study aimed to:
identify and map the plant communities in the forest and agroecosystems of Mt. Malindnag;
determine the floristic diversity and conservation status;
determine the plant species being threatened by utilization and habitat loss;
document indigenous knowledge on conservation;
develop a monitoring and conservation instrument among concerned communities ; and
formulate recommendations and strategies to increase awareness on plant diversity and conservation
The methods and procedures employed in the study are described in the following subheadings:
Location of Study Sites
The research sites were located in the municipalities of Don Victoriano, Misamis Occidentasl ( Barangays Mansawan, Gandawan and Lake Duminagat), Oroquieta City ( Sebucal, Mailen, Toliyok and Bunga, Lopez Jaena ( Peniel), Calamba (Mamalad and Siloy) and Concepcion ( Small Potongan and Marugang). These municipalities were within the watersheds and have tributaries to the two major river systems, Layawan and Langaran , and all within the Mt, Malindang Protected Area.
Participatory Approach: Organizing and Training Local researchers
To enhance awareness on Biodiversity Research Program and elicit community cooperation and participation, the Terrestrial Ecosystem Master Project ( TEMP) conducted a community information drive, meetings and consultations with the barangays included in the project, namely, Sebucal, Mialen, Toliyok and Bunga in Oroquieta City; Mamalad,in Calamba; and Peniel in Lopez Jaena, Misamis Occidental .
TEMP and socioeconomic and cultural (SEC) studies team conducted trainings on capability building for research assistants, researchers and local researchers. The participants were given a training-workshop on plant taxonomy, herbarium processing and management.
Vegetation analysis and Mapping
Two approaches were integrated to come up with a vegetation map of the northern landscape showing both vegetation structure
( physiognomy) as well as floristic composition of the plant communities (Figure 2). The first approach was the top-down or deductive approach, which analyzed remote sensing images; while the second was the inductive or bottom-up approach which analyzed field data. The top-down strategy focused on the different vegetation structures and their geographical distribution. The bottom-up gave an insight on the content of the different plant communities. The floristic composition provides the basis for the assessment of community diversity, the community threat and the economically important plants for the community.
Healthy canopies of vegetation have a very distinctive interaction with energy in the visible and near-infrared regions of the electromagnetic spectrum; absorption of energy in the blue and red region of the visible light, and high reflection of energy in the infrared region. Green vegetation indices were calculated through a combination of the visible red and the near-infrared bands of the satellite images. The range of vegetation indices was divided into different strata. The spatial representation of these strata was compared with altitude data. Some of these combinations were assumed to represent mossy forest and montane forest, mixed dipterocarp forest and agroforest. The almaciga forest type was based on the predominance of the almaciga species and cannot be detected by biomass/ altitude combinations.
Site Selection and Establishment of Sample Plots
Using the Landsat 7 imagery maps, the segment of the Mt. Malindang area comprising the Langaran and Layawan Rivers was selected for the field study. The segment was then divided into grids
( Figure 1). Sample grid selection for field studies was based on a proportional distribution of the grids over different vegetation strata, representing the elevation gradient, which were found in the image processing of satellite information. The grids contained the sampling sites for the research on the forest ecosystems, the agroecosystems and the grass-dominated fallowed areas. The choice of the plots within the sites was executed according to the subjective sampling method. Random sampling was not possible due to the limited accessibility of the area.
For the forest ecosystems, different sampling sites were set up on the north and south slopes ( within the same grid) because sunlight exposure was considered a relevant ecological factor. The number of sample plots per sample site was six.
For the tree layer, the dimensions of the sample nested plots in the study area were 20X 20 m. Within the plots, all trees with diameter at breast height (dbh) of 10 cm and more were recorded and their corresponding total heights were measured. Within the plot, a subplot of 5 x 5 m was laid out at a representative location to inventory the tree saplings, shrubs, herbs, pteridophytes, vines, and palms. Inside the 5 x 5 m subplot, a 1x1 m-quadrat was established to record bryophytes and lichens.
In agroecosystem, the gardens along the foothills, both in the northern and southern exposures, were observed. The sampling procedure followed was a transect-mosaic approach ( random sampling). The gardens along the transect were mapped and numbered on each exposure. Six gardens were selected randomly for sampling.: 20x20 m. 5x5 m and 1x 1 m sample plots, subplots and quadrats. The species and varieties of crops, shrubs, fruit trees saplings and herbs ( weeds, grasses and ornamental plants) were inventoried.
Altogether, 220 sample plots were established: 133 plots in the agroecosystem and 87 plots in forest ecosystems ( 15 in mossy forests, 21 in montane forests, 6 in almaciga forests, 12 in submontane dipterocarp forests, 8 in lowland dipterocarp forests, 12 in mixed dipterocarp forests, 7 in mixed lowland dipterocarp forests and 6 in plantation forests).
Two Subanon researchers and three Subanon laborers per barangay helped establish the plots and conduct inventory and assessment of plant species in the forests and agroecosystems.
The vegetation plot data consisted of species information and data variables. Species data consisted of species names found in the plot linked to their corresponding cover-abundance values; while data variables included ecosystem type, plot name, date, altitude, slope, and aspect.
Because the vegetation in the plots were measured and recorded using different methods and scales (DBH) measurements, frequency and cover percentage) the values were integrated into a common simple ordinary scale to make floristic classification possible. Under this method, each species should occur only once in the list and should appear under different growth forms ( e. g., tree and sapling) so as not to disturb the classification procedure, which is based on floristic composition .( Tables 1 to 3).
After the recording of the cover-abundance value, the species information is interactively stored in a database using the software Turboveg. This required input to complete flora list of the Mt. Malindang. The cover-abundance value and the vegetation layer were added under each species. After the data input, Turboveg was used to makes all types of selection, and to transform these selections to output files, which then became ready for clustering.
The floristic classification was done with the help of the program TWINSPAN (Hill 1979). This program is a divisive clustering technique,, which is used worldwide in vegetation research. The TWINSPAN ordering method is based on the mathematical algorithm of reciprocal averaging and results in a new matrix that shows a block structure along the main diagonal line of the matrix. The different block represent unique sample-species combination, which form the basis of the delineation of plant
Table 1. Integration of the 20x 20 m plot in three classes: trees with 10 dbh up including palms, pandan and tree fern________________________
10-20 20-40 >40_______
1-2 1 1 1
3-5 1 2 3
6-10 2 3 3_______
Table 2. Integration of 5x 5 m plot data in three classes: saplings, shrubs, herbs , vine and pteridophytes_______________________________
> 10 3____________________
Table 3. Upgrading scheme for tree species class due to high presence of saplings_______________________________________________________________
Number of Saplings DBH
10-20 20-40 >40_______
1-3 1->1 1->2 1->3
4-10 1->1 2->3 3->3
> 10 2->2 3->3 3->3_______
communities that are somehow homogeneous with respect to their species composition.
Final Arrangement and Interpretation of Tables
The phytosociological table produced by TWINSPAN was furthered organized using Megatab, a program that manually rearranges tables. It can handle a maximum of 24, 000 relevees and 5, 900 species, and can also produce synoptic tables. In addition, it can simplify many technical procedures, such as adding new relevees and combining species that used to require help from expert.
Sorting synoptical tables requires use of consistent principles for the classification of the status level of species. Comparind different clusters, a species maybe differential for a cluster or group of cluster or not. The following criteria were applied to exclusive differential, selective differential and preferent differential species:
Exclusive differential species
> 25% presence in the community and < 10% in the other community
>10% presence in the community and 0% in the other community
Selective differential species
Presence in the community > 50% and in the other community < 25%
Preferential differential species have significant higher cover abundance values in the community as compared with the other communities.
The data variables in the phytosociological table were the first source of ecological information, which can easily be correlated with the detected plant communities. In mountainous areas such as Mt. Malindang, altitude plays a decisive role on the highest levels of classification. At the lower levels of classification (determining variants of communities), altitude, slope, soil type and water conditions play critical roles.
Vegetation Map: Integration of Classification and Physiognomical Maps
Ecological information obtained trough GIS is used to modify the physiognomical map into a realistic vegetation map. Borders irrelevant to plant communities were deleted, while where necessary new borders were added. For example, in the ecological analysis, when a clear floristic difference was found between north (315-45 degrees) and south (125-235 degrees) facing slopes, appropriate borders where added to delineate such changes; likewise, the same was done when different forest types were found at different altitudes. Some vegetation types may only occur in very small areas, and therefore not chartable at such a minute scale. In such cases, that vegetation type was usually combined with the adjacent vegetation type into a complex type. Another method was by mapping the small areas (when they are low in number) as point information with symbols.
Different parameters for measuring the magnitude of floral species diversity were used. These include: (1) relative density, (2) relative frequency, (3) relative dominance, (4) species importance value, and (5) species similarity.
Density (D) – individuals of a species will be counted and the density value will be delivered using the following formula:
Number of individuals
Relative Density (RD)
Density of species A
Relative Density = x 100
Total Density of all species
Frequency (F) – the plots in which species A occurred will be counted and frequency value will be computed using the following formula:
Number of plots in which species A occurs
Number of plots examined
Frequency value for species
Relative Frequency = x 100
Total of frequency values for all species
Species basal coverage values
Species Dominance =
Note: Trees’ basal areas were taken at breast height
level, While shrubs at 3 cm above ground.
Relative Dominance (RD)
Dominance of species A
Relative Dominance = x 100
Total Dominance of all species
Species Importance Value (SIV) – as a rough and overall estimate of the influence or importance of plants species in the community. The importance value (SIV) was computed using the following:
SIV or ni = RD + RF + Rdom
RD= Relative Density
RF = Relative Frequency
Rdom = Relative Dominance
Shanon Index of General Diversity (H’)
H’ = -
Similarity Index (SI)
A + B - C
C = No. of species present in both sites A and B
A = No. of species present in site A
B = No. of species in site B
Locations of all accounted trees within one of the six 20 x 20 m plots site (center plot) were determined. Each plot was subdivided in smaller plots of 5 x 5 m. The tree species and the number of individuals per species were recorded. Profiling of all trees (10 cm dbh and up) was done at the center plots for the north as well as for the south-facing slope. The tress’ dbh, height, crown diameter, position in the plot, association (overlap with other trees), and all other aspects of stand structure were collected and processed for herbarium specimen vouchers.
Assessment of Conservation Status of Floral Species
Assessment of the conservation status of plant species revealed whether the plants were endangered, endemic, depleted, rare, economically and/or socioculturally important. The plants were classified according to the definitions provided by the International Union for Conversation of Nature (IUCN), Mace and Stuart (1994 and 2004), Rojo (1999), Merrill (1926), Zamora and Co (1986), and the Department of Environment and Natural Resources (DENR) (2000):
endangered species – actively threatened with extinction; its survival is unlikely without protective measures
endemic species – confined to a certain geographical region or its parts
rare species – not under immediate t6hreats of extinction but occurring in such small numbers or in such localized or specialized habitats that it could quickly disappear if the environment worsens; needs watching
depleted species – although sufficiently abundant for survival, the species have been nearly depleted and in decline as a result of natural causes or human activities
economically important species – based on known uses
Based on the conservation status of species, the list of threatened species was prepared. A separate list of locally threatened species was likewise prepared, based on the number of individuals per plot. The list were merged and compared to the list of species used by the people, as determined by the SEC studies team. The usage intensity of the species was calculated from household to community level. This information indicated the pressure the pressure the demand of the species exerted on the resource base.
Status of Indigenous Knowledge within the Community
Indigenous knowledge (IK) on phenomenal occurrences, as well as beliefs and local species indicators were gathered in several barangays using focus group discussion (FGD) and knowledge indicator (KI) interviews.
KI information from both the floral data and the SEC studies team data were synchronized using scientific/technological knowledge. The results and insights served as inputs to the formulation of floral diversity monitoring and conservation practices.
Biodiversity Monitoring and Evaluation System (BIOMES)
The instrument for biodiversity monitoring and evaluation was developed by Central Mindanao University and the Bukidnon Resource Foundation (BRF), Incorporation. A training-workshop was held with the members of the community monitoring teams and TEMP researchers. A training manual on Biodiversity Monitoring and Evaluation System (BIOMES) was developed consisting of 10 modules.