Cebu Island Research Articles

Abundance and Characteristics of Microplastics in Commercially sold fishes from Cebu Island, Philippines

This study documents microplastics (MPs) in the top three commercially sold fishes viz. Auxis rochei , Rastrelliger kanagurta and Chanos chanos in major public markets of Cebu Island, Philippines. MPs were found in the gastrointestinal tracts (FGIT) and quantified and characterized according to size, type, and color. In general, nine (97.3%) of 81 FGIT samples contained 635 total pieces of MPs with size ranging 0.01 to 0.50 and 1.00 to 2.00 mm. Transparent microfibers (91%) were the most predominant MPs, with blue (48%) as the most common MP color observed, followed by red (39%), black (8%) and white (5%). Chanos chanos proved to be the most susceptible fish to MP ingestion with a mean average of 11.6 pieces per individual fish, followed by A. rochei with 6.6 pieces, and R. kanagurta with 5.3 pieces. The results indicated that MPs were ubiquitous and high in commercially sold fishes in major public wet markets of Cebu Island, Philippines. The ingestion of fishes is of primary concern as a route of human exposure to MPs because they filter a large volume of seawater and are typically eaten whole without gut removal. Further study is needed on the potential consequences of MPs to aquatic populations to assess comprehensive exposure integrating multiple sources and routes.

Species composition, relative abundance, and distribution of land snail species in Mt. Lantoy Key Biodiversity Area, Cebu, Philippines

Abstract. Rosales R, Lillo E, Alcazar SM, Colita L, Caballero J, Malaki AB. 2020. Species composition, relative abundance, and distribution of land snail species in Mt. Lantoy Key Biodiversity Area, Cebu, Philippines. Biodiversitas 21: 5438-5447. This study aimed to establish an inventory of land snails in Mt. Lantoy, Cebu Island, Philippines. A two-person team conducted sampling on eight permanent plots with an elevation range of 182 m-691 m. The study has listed a total of 872 individuals represented by 25 species belonging to 15 genera and nine families. Seven families belong to the air-breathing pulmonate group, Order Stylommatophora: Bradybaenidae, Camaenidae, Trochomorphidae, Achatinidae, Ariophantidae, Helicarionidae, Helicinidae. Two families were under the prosobranch group, Order Caenogastopoda: Cyclophoridae, and Pupinidae. The Cyclophoridae was the richest family with five species, followed by Bradybaenidae, Camaenidae, Helicinidae, having four species. The Trochomorphidae and Helicarionidae have three species. The Pupinidae has two species, while the Achatinidae and Ariophantidae has one species each. There were three (3) endemic and ten (10) new island record species collected and identified with four (4) species that were classified as rare. Rysotta otaheitana Ferussac 1821 was the most abundant, representing 25.22% of the total number of individuals. The Leptoma nitidum ancilis Bartsch 1918 has the widest geographical distribution with a constancy rate of 100%. Widespread species appear to be more abundant, while other species were geographically restricted in few study areas.

Bouguer Anomaly of Central Cebu, Philippines

ABSTRACT Cebu Island in Central Philippines consists of a Cretaceous basement complex capped by mostly Tertiary sedimentary units. Recent mapping conducted in Central Cebu revealed limited exposures of lithologies, especially those comprising the basement complex. The gravity method was utilized to generate Bouguer anomaly maps for Central Cebu. These geophysical maps provide the first images of the subsurface extent of the basement units. A prominent nearly circular gravity anomaly high is consistently observed in the Bouguer anomaly maps coinciding with the location of dense basement and intrusive rocks. However, field mapping revealed the very limited surface exposure of these units. The gravity highs recognized in the residual anomaly maps may correspond to the larger extent of the intrusive units at depth. The broad gravity high observed in the regional anomaly map may define the extent of the subsurface distribution of the Cretaceous basement complex.

First Distribution Record of North Philippine Temple Pitviper (Tropidolaemus subannulatus Gray, 1842) on Cebu Island, Philippines

This paper presents the newly documented single specimen of the North Philippine temple pitviper (Tropidolaemus subannulatus), one of the venomous endemic snakes of the Philippines. The species has never been recorded in Cebu Island in the last two waves of survey in 1986 and 2016. The new record for Cebu Island on 13 Apr 2018 was a male juvenile T. subannulatus in a diverse forest over limestone in Mount Lantoy key biodiversity area (KBA), with an elevation of 648 m having geographic coordinates of 9.91395ºN and 123.51207ºE in Barangay Cansuje, Argao, Cebu, Philippines. The specimen was recorded in the permanent vegetation plot no. 1, established within the secondary natural forest, perching on the vines (Piper sp.). Some tree species found within the collection area were the following; Garcinia rubra, Ficus ampelas, Canarium asperum, Calophyllum blancoi, Gomphandra luzoniensis, and Goniothalamus almeri. The distance of occurrence from the ground is approximately 3 m. It seemed that the microhabitat characteristics of Mt. Lantoy KBA, particularly the forest over limestone in Barangay Cansuje, is favoring the survival of T. subannulatus.

Short communication: Diversity of cave-dwelling bats in Cebu Island, Philippines

Abstract. Alcazar SMT, Lit Jr IL, Rebancos CM, Barrion-Dupo ALA, De Guia APO, Bantayan NC, Alvarez JDV. 2020. Short communication: Diversity of cave-dwelling bats in Cebu Island, Philippines. Biodiversitas 21: 3249-3254. The species composition and richness of cave-dwelling bats in 16 caves of Cebu Island were studied to provide resource managers and local government units in Cebu baseline information that may be used toward conservation and sustainable utilization and management of local cave resources. Stationary and mobile mist-netting were employed at the entrance and dark zones of the caves to maximize the capture of bats. The study accounts for 15 species of cave bats, of which two were unidentified but are believed to be potentially new species, namely Rhinolophus sp. and Myotis sp., and three are new distribution records to Cebu, namely Rhinolophus philippinensis, Eonycteris robusta, and Megaderma spasma. In terms of richness values, Balay’g Agta holds six species and the remaining caves have less than five species. The presence of endemic, potentially new species and new distribution records of bats presents high conservation value and raises concern and calls for urgent action to protect the caves and the resources therein.

Phenotypic Characterization and Ethnobotanical Inventory of Chili Pepper (Capsicum spp.) Cultivars in Cebu Island, Philippines

Phenotypic Characterization and Ethnobotanical Inventory of Chili Pepper (Capsicum spp.) Cultivars in Cebu Island, Philippines

Geochemistry of the Late Cretaceous Pandan Formation in Cebu Island, Central Philippines: Sediment contributions from the Australian plate margin during the Mesozoic

AbstractThe Late Cretaceous Pandan Formation in Cebu Island is one of the oldest sedimentary units in the Central Philippines. The inconsistencies in geological descriptions and interpretation of the depositional environment of the Pandan Formation complicated efforts to determine the origin and tectonic history of the basement of Cebu Island. This study therefore looks into the petrological and geochemical characteristics of the Pandan Formation and their implications for the tectonic development of the Philippine Arc during the late Mesozoic. Petrographic analyses indicate significant contribution from mafic sources with additional inputs from felsic rocks, siliciclastics and metamorphic sources. Enrichment of detrital quartz from felsic volcanic and plutonic rocks, as well as from siliciclastic and metamorphic sources, has shifted the SiO2 composition of the Pandan clastics from a mafic to a more intermediate source. Whole‐rock geochemical analyses revealed low SiO2/Al2O3 = 4.21, low K2O/Na2O = 1.16, low Th/Sc = 0.13, low Th/U = 2.78, high La/Th = 4.51, significantly low REEs = ca 76.45 ppm and low LaN/YbN = 4.28. A slight negative chondrite‐normalized Eu/Eu* (0.91) anomaly and significantly high PAAS‐normalized positive Eu/Eu* (1.39) values are consistent with derivation from a young undissected magmatic arc terrane. Tectonic discrimination diagrams suggest formation in an oceanic island arc to active margin/collision zone modelled to be located at the oceanic leading edge of Australia. Rapid uplift and erosion of the magmatic arc and older allochthonous blocks gave way to the rapid deposition of the Pandan Formation in the Late Cretaceous at the subequatorial region.

Diversity and distribution of ferns in forest over limestone in Cebu Island Key Biodiversity Areas (KBAs), Philippines

Abstract. Lillo EP, Malaki AB, Alcazar SMT, Rosales R, Redoblado BR, Pantinople E, Nuevo RU, Cutillar RC, Almirante A, Buot IE Jr. 2020. Diversity and distribution of ferns in forest over limestone in Cebu Island Key Biodiversity Areas (KBAs), Philippines. Biodiversitas 21: 413-421. Three forest areas of Cebu Island, Philippines were recognized as Key Biodiversity Areas (KBAs) by Department of Environment and Natural Resources [DENR], Philippines based on the criteria of vulnerability and irreplaceability, namely Nug-as of Alcoy, Palinpinon Range of Dalaguete, and Mt. Lantoy of Argao. The study aimed to assess the composition, diversity, and distribution of ferns in the aforementioned KBA's. Quadrat at 20 m x 20 m was established within the 2000 m transect line at an interval of 200 m. Result showed a total of 50 species, categorized into 15 families and 29 genera for 30 quadrats. Twelve species were considered as new records on Cebu. Thirteen species were recorded in both Mt. Lantoy and Nug-as forest KBA’s, but absent in Palinpinon range. While 6 species were recorded as unique to Nug-as forest. Nug-as forest and Mt. Lantoy showed a relative value of very high species diversity. Nug-as forest and Mt. Lantoy KBA forming into one cluster and Palinpinon range proved to have a distinct fern species composition, and form another cluster. Local government units (LGU) in every KBA need to recognize the necessity of biodiversity information in their localities that would facilitate information sharing and awareness, hence enhancing protection and conservation of unique biodiversity, since they are at the forefront of local action.

Genetic Diversity and Relative Abundance of Cebu Black Shama (Copsychus cebuensis Steere) in Fragmented Forests of Cebu Island, Philippines

This study determined the relative abundance of Cebu black shama (Copsychus cebuensis Steere) in selected isolated forest fragments in Cebu Island, Philippines and their genetic diversity based on 619 bp cytB gene. Mist nets were used to capture the bird in these forest fragments. Four contour feathers were plucked from the body of the caught birds, before they were released, and were stored in tubes with 70% ethanol before DNA extraction. Fifty-nine black shama (C. cebuensis) individuals were encountered from the visited territories. At least 13 black shama individuals were estimated to inhabit one hectare of forest habitat. For the first time, analyses of mitochondrial genes revealed that C. cebuensis had a long evolutionary history from an initially large and stable population that went through recent expansion resulting from a recent isolating or bottleneck event as indicated by high haplotype diversity (Hd) and nucleotide diversity (πn), i.e. Hd>0.50 and πn>0.005, and non-significant values of Tajima’s D test, Fu and Li’s D*, and Fu’s Fs statistics. It is hypothesized that this bottleneck event was habitat fragmentation. Furthermore, phylogenetic analyses of C. cebuensis supported its monophyly.

RUNOFF ESTIMATION USING SCS RUNOFF CURVE NUMBER METHOD IN CEBU ISLAND

Abstract. Cebu, with its growing development and increasing demand for water, needs tools and inputs to efficiently understand and manage its water resources. Rainfall runoff models were developed to model surface runoff which may be used to assess water availability. Soil Conservation System (SCS) Runoff Curve Number (CN) method predicts runoff based on an empirical curve number for ungauged watersheds. This study aims to estimate the amount of runoff for the catchments of Cebu Island using the SCS-CN Runoff technique. The data needed for the application of the method in this study were rainfall distribution data, land use/land cover and soil texture for curve number assignment, LiDAR DEM for the delineation of the catchments, and supporting runoff measurements from a different runoff estimation model for assessment of the results. The collected data were prepared by assigning the mean statistics of the rainfall distribution and the composite curve number for each catchment using Geographic Information System (GIS). The calculation of the runoff was also done using the same framework. Maps representing Cebu Island’s catchments’ runoff estimates were produced. Since observed runoff data were unavailable, the results were verified by comparing the SCS-CN estimated runoff to the results of a physically-based distributed hydrologic and hydraulics modelling software, FLO-2D. The SCS-CN estimations were found to coincide with the FLO-2D runoff estimates based on various statistical assessments. Although the results may have higher uncertainties due to the unavailability of observed runoff data, the SCS-CN Runoff method provided relevant results to that of a complex simulation model. Thus, the method may be applied to estimate runoff of ungauged catchments of Cebu Island, the results of which could provide relevant information for water resource management.

GEOSPATIAL ECOLOGICAL FOREST CORRIDOR MODELLING IN THE MOUNT LANTOY KEY BIODIVERSITY AREA

Abstract. In biodiversity conservation, ecological corridors are assumed to increase landscape-level connectivity and to enhance the viability of otherwise isolated wildlife populations. Mapping these corridors serves as a feasible method to support forest management efforts in pinpointing areas to give special attention to. Here, we assess the current forest presence in the 3,000 hectare Mt. Lantoy, Key Biodiversity Area in Argao, Cebu and present potential forest corridors that could enhance the canopy cover of the current protected area. We present a method to map the potential corridors through the identification of the forest patches obtained from the global forest cover dataset and the creation of a species distribution model for the black shama, an endemic bird species in Cebu island and a great biodiversity indicator for the area. Our ecological corridors were acquired through the sum of the cost distance rasters obtained from the weighted overlay and cost surface tools of the black shama habitat suitability model. With the obtained corridors from the study, four potential forest corridors/ extensions were identified connecting five different forest patches. These corridors have areas that range from 0.47–2.17 square kilometers, with a potential to increase the forest cover in the KBA to more than 33% after corridor modelling.

Local Communities' Knowledge, Attitude and Perception Toward Cebu Black Shama (Copsychus cebuensis Steere) and its Habitat Characteristics in Cebu Island, Philippines

A knowledge, attitude & perception (KAP) survey was conducted in four important bird areas (IBAs) in Cebu island, Philippines towards the protection and conservation of the Cebu black shama (Copsychus cebuensis) and its habitat. Similarly, the habitat quality of the black shama in the island was also assessed in terms of vegetation composition and diversity. A total of 193 households were interviewed from July 2013 to December 2013. Most of the respondents only finished elementary and high school levels. However, their mean knowledge score was above 6.50 while their attitude mean score was above 9.40. Their perception scores, on the other hand, were highly positive. Regardless of their educational attainment, people living near the identified black shama territories were highly knowledgeable, aware and positive towards the protection and conservation of the endangered bird and its habitat. Forty-five black shama territories were sampled employing 20 m x 20 m quadrats from September 2013 – February 2014. The black shama habitat is characterized with high plant species diversity (H’>3.50), even plant distribution (e >0.75), and low dominance index (D >0.01). In terms of vegetation composition, the black shama habitats were not similar. Integrating the social and ecological knowledge to conservation will likely promote a wider perspective of effective conservation program implementation than social or ecological knowledge alone.

Mesozoic porphyry Cu–Au mineralization and associated adakite-like magmatism in the Philippines: insights from the giant Atlas deposit

The Atlas porphyry Cu–Au deposit is located in central Cebu Island in the Philippines, with a proven mineral reserve of 1420 Mt at 0.45% Cu, 0.24 g/t Au, 0.018 g/t Mo, and 1.8 g/t Ag. It is associated with the Lutopan quartz diorite porphyry stock that was emplaced into the Cretaceous volcano-sedimentary sequences of the Cansi Formation. Two stages of hypogene alteration have been identified at Atlas: stage I quartz–magnetite ± chalcopyrite ± pyrite veins associated with potassic and propylitic alteration and stage II anhydrite–pyrite–chalcopyrite ± specularite veins associated with phyllic alteration. Supergene gypsum veins are also present. Mineralization is mainly associated with the stage I and stage II veins. The Lutopan quartz diorite porphyry yielded a zircon U–Pb age of 108.5 ± 1.6 Ma and is characterized by high Sr/Y (54–69), with the corresponding magma having high oxygen fugacity (avg. ΔFMQ +2.7, avg. Ce4+/Ce3+ of zircon = 439) and H2O concentrations (presence of amphibole and biotite phenocrysts) and low magmatic temperatures (avg. Ti-in-zircon thermometry = 706 °C). The relatively low La/Yb ratios (9–11), listric-shaped normalized REE patterns with weak or absent Eu anomalies, together with zircon eHf(t) values of 3.4 to 10.0, whole-rock ISr values of 0.70373–0.70382, eNd(t) values of 2.4–3.4 and Mg numbers of 49–53 suggest that the Lutopan quartz diorite porphyry was likely derived from partial melting of young lower continental crust or interaction between asthenospheric melts and lower crust melts, that evolved to adakite-like trace element compositions through amphibole fractionation. Stage I veins yielded a pyrite Re–Os isochron age of 110.2 ± 5.6 Ma, making Atlas the only Mesozoic porphyry deposit discovered in the Philippines.

Hunting in the Rain: Unusual Behavior by the Tiger Beetle Cylindera discreta elaphroides (Doktouroff) (Coleoptera: Cicindelidae) in Atropical Forest on Cebu Island, Philippines

Hunting in the Rain: Unusual Behavior by the Tiger Beetle Cylindera discreta elaphroides (Doktouroff) (Coleoptera: Cicindelidae) in Atropical Forest on Cebu Island, Philippines

Early Cretaceous adakite from the Atlas porphyry Cu-Au deposit in Cebu Island, Central Philippines: Partial melting of subducted oceanic crust

In the Philippine island arc system, there are widely developed Cenozoic arc volcanic rocks, adakites and large Cu-Au deposits. Besides, only two early Cretaceous adakitic intrusions have been found in the entire Philippines so far, i.e., the Lutopan Diorite and the adjacent Kansi diorites in Cebu Island, Central Philippines. The Lutopan Diorite (diorite to quartz diorite in lithology) is the ore-forming intrusion of the giant Atlas porphyry Cu-Au deposit, which is the only Cretaceous porphyry deposit in the Philippines. In this study, geochronology and geochemistry of the Lutopan Diorite in the Carmen pit of Atlas porphyry Cu-Au deposit are investigated in detail, by comparing them with the previously studied Early Cretaceous Kansi diorites and arc volcanic rocks in Cebu Island, to reveal the petrogenesis and magma sources. The Carmen diorites are characterized by moderate SiO2 and MgO contents, coupled with high Na2O and low K2O contents, LREE-enriched and listric REE distribution patterns, low Yb and Y contents, high Sr contents and thereby high Sr/Y ratios, and low (87Sr/86Sr)i (0.7037–0.7038), typical of modern island arc adakites. Zircon U-Pb ages of the Carmen diorites are 109 Ma − 107 Ma in the Early Cretaceous, which is identical with that of the Kansi diorite in the north within error. Both the Carmen and Kansi diorites were formed in intra-oceanic island arc settings. The Carmen diorites show listric REE patterns and low Nb/Ta, high Zr/Sm ratios, suggesting they are formed by partial melting of subducted oceanic crust in amphibolite facies, which is different from the garnet amphibolite- to amphibole eclogite-melting genesis of the Kansi diorites. There is a small amount of subducted sediments in the magma source of Carmen diorite, as further revealed by εNd(t) (+7.1 to +10.6), zircon εHf(t) (+3.3 to +3.9) values, and low Th/U ratios. The Carmen adakitic magma did not undergo significant interaction with mantle peridotite during magma ascent as indicated by the moderate MgO content and Mg# value, and quite low Cr and Ni contents, distinguished from the Kansi diorite (high-Mg adakite) that have high MgO, Mg#, and Cr and Ni contents. We suggest that the nearly contemporary Lutopan Diorite and Kansi diorite are two independent Early Cretaceous adakitic intrusions in Cebu Island, although they are both closely associated with Cu-Au mineralization. The slab-melting genesis and high oxygen fugacities of the Lutopan Diorite are the most important factors to cause Cu enrichment in the magma, which is necessary to form the giant Atlas porphyry Cu-Au deposit.

On the identity of Sundathelphusa philippina (von Martens, 1868) (Decapoda: Brachyura: Gecarcinucidae) from the Philippines, with descriptions of two new species.

The taxonomy of the Sundathelphusa philippina (von Martens, 1868) species group (Brachyura; Gecarcinucidae) from the Philippines is revised, and two new species are described. Sundathelphusa philippina sensu stricto is here restricted to the Bicol Peninsula of southern Luzon, and to the islands of Samar and Leyte. It is one of the largest freshwater crabs in the archipelago, reaching carapace widths of more than 53 mm. Sundathelphusa cebu sp. nov. from Cebu Island is superficially similar to S. philippina in morphology but can be separated by a suite of carapace characters. Sundathelphusa quirino sp. nov. from northern Luzon is the most distinct of the three taxa, with a distinctly more swollen carapace, relatively wider male pleon and a straighter male first gonopod. Sundathelphusa spelaeophila Stasolla, Abbarchi Innocenti, 2015, is also shown to be a junior synonym of S. philippina sensu stricto.

Native and alien plant species inventory and diversity in disturbed forests and its economic value.

The study was conducted to assess the native and alien plant species in one of the highly disturbed forest (S1) and less disturbed forest (S2) in Mt. Manunggal, Cebu Island, Philippines. Twenty-four quadrats with a size of 20mx20 m were established using a quadrat sampling technique to identify and record all plant species. Diversity indices were utilized to determine species abundance, richness, evenness, and diversity. There was also the characterization of sites concerning anthropogenic activities and economic uses of native and alien plant species. Results showed that there was apparent domination of alien plants in terms of species richness and abundance in both sites (S1; R=62 species; N=10519; S2; R=55; N=32739). However, there was higher species richness (S1; R=62 and S2; R=30) and diversity (S1; H’=2.76, D=0.10 and S1; H’=2.41, D=0.11) but lower abundance (S1; N=10519 and S2; N=32739) and evenness (S1; PE=0.67 and S2; PE=0.73) in S1 than in S2. The high abundance and evenness of alien plant species in S2 could be due to high anthropogenic activities and its economic value. These factors indirectly assist in the introduction and persistence of alien plant species in disturbed ecosystems by increasing alien plant invasion which usually results in a higher diversity of alien plant species in highly disturbed sites. Assessment on the negative impacts to native plant species by alien plant invasion, enhanced by anthropogenic activities, must, therefore, serve as bases in future directions and implication for restoration and conservation of the remaining forests of Mt. Manunggal, Cebu Island, Philippines.

Arthropod functional feeding groups as indicators of smallscale disturbance: a first approach in Mt. Manunggal, Cebu Island, Philippines

Arthropod functional feeding groups as indicators of smallscale disturbance: a first approach in Mt. Manunggal, Cebu Island, Philippines

Floristic Inventory and Ethnobotany of Wild Edible Plants in Cebu Island, Philippines

The study discussed the  diversity, utilization, socio-economic value and threats associated to the wild edible plants (WEPs) in Cebu Island, Philippines. Semi-structured  interview, field observations and pairwise ranking were utilized to  generate responses from purposively-selected  informants living in  three mountain communities in Cebu: Mt. Kapayas, Catmon, Nug-as Forest Reserve, Alcoy and Cantabaco Forest, Toledo. The study recorded a total of 168 edible plant species belonging to 111 genera and 97 families. Majority of plant habits of the recorded plants were trees (42.94%), herbs (30%) and shrubs (14.71%). The recorded use of WEPs include food, medicine, construction/technology, beverage, forage, food coloring and condiments where 30% of the informants suggest the marketability of the WEPs and 14.7% of the WEPs were reported as alternative food source. Test for use diversity showed significant difference in the uses of WEPs in the three sites (X2 = 2.46, α = 0.05). Pairwise-ranking results indicated that selective cutting for construction and technology, natural disaster and agricultural expansion are key threats to WEPs in these areas. The study suggests 1) public awareness and community-based management at all levels to lessen threats, 2) further investigation on nutritive and socio-economic values;and 3) investigation of pharmacological profiles to evaluate medicinal benefits.  Keywords : wild edible plants, ethnobotany, alternative food source

Effects of Environmental Factors and Alien Plant Invasion on Native Floral Diversity in Mt. Manunggal, Cebu Island, Philippines

The status of native floral diversity in Mt. Manunggal, Cebu Island, the Philippines in relation to environmental factors and alien plant invasion has not been recorded and published. To assess factors influencing native plant communities in Mt. Manunggal, a vegetation survey of native and alien plants, as well as selected environmental variables at two sites (Site 1- invaded plot; Site 2- adjacent uninvaded plot) were measured, and anthropogenic disturbances observed using a t-test, regression analysis, and Pearson correlation. For each site, selected environmental parameters, as well as native and alien plant abundance and diversity, were determined last October-November, 2016. There was also a characterization of sites with respect to anthropogenic disturbances. Altitude (t= -14.11, p=0.000), soil temperature (t=2.68, p=0.014), and light intensity (t = -2.61; p=0.016) significantly differed between study sites due to the complex topography and geology of Mt. Manunggal, the variation in floral cover, and degree of anthropogenic activities. Among all environmental factors at both sites, altitude was highly positively correlated to alien plant abundance (r=0.709;p=0.000) at Site 1 while native plant abundance at Site 2 was negatively correlated with soil pH (r=-0.579;p=0.003).There was an apparent domination of alien plants in terms of species richness and abundance at both sites and this could have significantly affected native plant abundance. The strong correlation of environmental parameters to alien plant invasion could favor the continued dominance of alien plant species, resulting in a further decrease of native species.