Researches:
Article title: Mapping Hotspots of Human Impact on Native Dendroflora Biodiversity in Cebu Island, Philippines
Authors: Isabella Pauline L. Quijano, Mary Joyce L. Flores, and Chito L. Patiño
Publication title: Philippine Journal of Science 150(S1):455-466, March 2021
Abstract:
The continuing pressure on the natural environment exerted by human activities such as land conversion has been threatening to drive tens of thousands of species to extinction globally for decades. Species conservation requires identifying species ranges impacted by threats, which helps predict localized extirpations and potential extinctions. This paper assessed the human pressures that threaten the local biodiversity in Cebu Island, Philippines, to help prioritize actions to manage and mitigate human impacts on local biodiversity. Hotspots, where modeled dendroflora species richness is compromised, were identified through a spatial overlay of pre-defined high-resolution human pressure variables. A notable observation was that the largest and only protected KBA-the Central Cebu Protected Landscape (CCPL)-had the highest percentage occurrence of medium to high threats within its boundaries, which could be attributed to its proximity to highly populated municipalities and cities. More importantly, possible areas of refuge for key species were identified. These areas could be appropriated as local restoration sites by the local government units of Mt. Lanaya and Nugas forest in the south of Cebu since these KBAs had high dendroflora richness but with less occurrence of high threats. The resulting maps could also be used as important references for targeted conservation management programs to help mitigate the threats that are driving local species to their decline and for preemptive planning of local and national conservation agenda.
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Article title: Effect of the MV St. Thomas Aquinas Oil Spill on Zooplankton Composition and Abundance in Mactan Island, Cebu, the Philippines
Authors: Mary Joyce L. Flores, Judith R. Silapan, and Brisneve Edullantes
Publication title: Journal of Nature Studies 19(1), July 2020
Abstract:
A survey of zooplankton composition and abundance was conducted on four nearshore waters last May 2014, 9 months after the oil spill by the passenger vessel "MV Saint Thomas Aquinas." Samples from three sites hypothesized to represent different degrees of oil contamination along the south coast of Mactan Island in Cebu, the Philippines were compared with those from the reference site in Dalaguete, Cebu. A total of six phyla with over 15 species and a density of 630 individuals/L of micro-and mesozooplankton were identified where ciliates specifically aloricates coming out as the most numerous. The average zooplankton density in the reference site (mean=143) differed significantly (p=0.04) from zooplankton density observed in S2 (mean=12.33), a moderately affected site. The aloricate ciliates, the copepods, and the zooplankton eggs were evident in all the sites. Although there was no significant spatial variation (p<0.05), the aloricates were more abundant in the unaffected and lesser affected sites. The copepods (p<0.01) and zooplankton eggs (p=0.03 and p<0.01) appeared to be good zooplankton predictors for the effects of the oil spill in this study as they have significantly higher abundance in the unaffected and least affected sites while controlling for other factors. Further investigation is recommended to monitor the temporal dynamics of the zooplankton population and abundance taking into consideration other intervening factors such as physicochemical factors, trophic relationships especially with bacteria, as well as the organisms' physiology, behavior, life stages, and sizes. The use of ratios of abundances or other indices can also be explored. Regular monitoring is strongly suggested especially in areas where the probability of oil spills is high and data is absent.
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Article title: Analyzing the Status of Mango Trees in Brgy. Cantipay, Carmen, Cebu Using Ndvi and Time Series Clustering
Authors: R. B. Navaja, F. P. Campomanes, C.L. Patiño, M. J. L. Flores
Publication title: The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences 42(4), December 2019
Abstract:
The Department of Agriculture – Region VII reports that many mango orchards in Cebu province are dying because of the absence of required post-harvest attention. Lacklustre yields and erratic pest infestations have driven some farmers and growers to abandon mango orchards. To help revive low-yielding mango orchards, there is a need to distinguish actively bearing mango trees from those that remain dormant throughout the year. Using remote sensing techniques, mango trees from separate orchards in Brgy. Cantipay, Carmen, Cebu were mapped and studied using multi-temporal Sentinel-2 data (from January 2018 through May 2019). Prior to that, a field visit was conducted to survey the area using UAVs and field observation, and in the process, was able to identify an abandoned mango orchard. Pixel-based Normal Difference Vegetation Index (NDVI) values were extracted from each of the 822 geotagged mango trees with an average of 16 trees among 53 divisions. Time series were derived from the average of the NDVI values from each division and plotted per month of extraction from oldest to latest. Clustering was applied to the time series data using Hierarchical Clustering with Ward’s Minimum Variance as an algorithm to determine the divisions with the closest time series. Using the resulting dendrogram as basis, two major clusters were selected based on the value of their distances with each other: Cluster 1 containing 29 Divisions, and Cluster 2 containing 24 Divisions. Cluster 1 contains most of the Divisions in and around the biggest active mango orchard. In contrast, Cluster 2 contains most of the Divisions that are in and around the previously identified abandoned mango orchard. An alternative dendrogram was also created by using Complete Linkage algorithm in Hierarchical Clustering, after which 3 relevant clusters were selected. The second dendrogram highlights the stark difference between Division 1, contained in Cluster 3, from the rest of the other clustered divisions at 2.17 units from the next closest one. Notably, Division 1 is located smack in the middle of the abandoned orchard The remaining clusters, Cluster 2 with 21 divisions containing most of the divisions in the abandoned orchard, is 2.46 distance units away from Cluster 1, which has 31 and hosting most of the divisions in the active mango orchards. Two major clusters emerged from using the two algorithms. Divisions with higher and more variant NDVI values seemed to come from the mango trees which were more active during the fruiting cycle. Divisions from the abandoned mango orchards were observed to have lower and less varied NDVI values because of minimal activity in the trees. Other Divisions clustered under the abandoned orchard could have been juveniles based on their size.
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Article title: Geospatial ecological first corridor modelling in the Mount Lantoy key Biodiversity Area
Authors: I. P. Quijano, M. J. L. Flores, and A. B. Malaki
Publication title: The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-4/W19, 2019
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.
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Article title: Monitoring Vegetation Cover Change Using Vegetation Indices in Tangbo River, Barangay Tangbo, Samboan
Authors: J. S. Yang, F. P. Campomanes, C. L. Patiño, and M. J. L. Flores
Publication title: The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-4/W19, 2019
Abstract:
Tangbo River is an important resource in Cebu’s southern town of Samboan for being the site of Aguinid Falls, a known tourist destination. Monitoring the changes in the river’s riparian vegetation is important since it has impacts on its ecological role of helping maintain biodiversity and river water quality. This study aims to detect vegetation index changes along the Tangbo River corridor using three vegetation indices: NDVI, EVI, NDMI, and Tasseled Cap indices, specifically for the years 1998, 2004, 2009, 2016, and 2019. It also aims to monitor the changes in NDVI and EVI values alongside tourism arrivals in Aguinid in 2018.Cloudless Landsat 5 (1998, 2004, 2009, and 2016) and Landsat 8 (2019) imagery were selected. Thirty reference points were plotted along the river with a 30-m distance between each point. Vegetation Indices (VI) and Tasseled Cap values were generated using data from these points and were compared for each selected year. NDVI and EVI values from the same reference points used in Landsat were generated from selected cloudless months of 2018 Planetscope imagery. Inbound tourist records were acquired from the tourism office of Samboan and the tourism arrivals for the year 2018 was then graphed with the Planetscope VI values for better visualization.Landsat imagery showed that there was a general upward trend in the vegetation indices from 1998 to 2019. Tasseled Cap Greenness and Wetness showed an increase in values from 1998–2019 while Tasseled Cap Brightness showed the opposite. Results from Planetscope data for the year 2018 showed that there was an inverse pattern between NDVI and tourism arrivals. Tourism arrivals peaked during the months of April and May based on annual records, while VI values dropped. On the other hand, both VI values peaked towards the last quarter of the year while tourist numbers dropped. This suggests that the pattern of VI values and tourism arrivals seemed to be influenced by seasonal changes rather than with each other. Findings from the study shows that further data collection is required to be able to establish a relationship between tourism and vegetation index values.
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Article title: Runoff Estimation Using SCS Runoff Curve Number Method in Cebu Island
Authors: F. C. Cayson, C. L. Patiño, and M. J. L. Flores
Publication title: The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-4/W19, 2019
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.
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Article title: Effects of Environmental Factors and Alien Plant Invasion on Native Floral Diversity in Mt. Manunggal, Cebu Island, Philippines
Authors: Jake Joshua Chi Garces and Mary Joyce Lapa Flores
Publication title: Current World Environment 13(3):390-402, December 2018
Abstract:
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.
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Article title: Abundance and population profile of Helicostyla daphnis (Stylommatophora: Bradybaenidae), an endemic snail of Cebu, Philippines
Authors: Mary Joyce L. Flores
Publication title: Journal of Biodiversity and Environmental Sciences (JBES) 5(1): 477-491, 2014
Abstract:
Helicostyla daphnis is a tree snail endemic to Cebu, Philippines. The study aimed to survey and compare the abundance and population profile (by age category) of Helicostyla daphnis in North Cebu and South Cebu in relation to season and other physicochemical factors. Sampling was done twice between April and September 2013. For snail sampling, a standardized direct search equivalent to a two-hour sampling effort in a total of eighteen quadrats in six sites was used. Elevation, air temperature, relative humidity, surface soil pH, and soil exchangeable calcium were measured on each quadrat. Independent t-test and Pearson correlation were used to relate abundance to the physicochemical variables. Snail abundance was significantly higher (p<0.01) during the dry season (dry=783 snails; wet=436). South Cebu had higher total abundance (dry = 477; wet = 284) compared to North Cebu (dry = 306; wet = 152). Adult snails dominated at 87% of total abundance during the dry season and 74% during the wet season. Neonates were present only during the wet season, contributing 5% to total abundance. The presence of eggs in both seasons could mean year-round reproduction; but increased egg abundance and significant presence of neonates imply higher reproductive activity during the wet season. Relative humidity and air temperature were the identified major determinants of abundance as they affect the species’ ability to avoid desiccation stress. The rate of harvesting of H. daphnis cannot also be ruled out as a factor affecting abundance between location.
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Article title: Effects of physicochemical factors and the local ecological knowledge on the population of Helicostyla daphnis (Broderip, 1841) in Borbon and Sogod, Cebu, Philippines
Authors: Funesto, E.G.M. and Flores, M.J.L.
Publication title: Applied Ecology and Environmental Research 15(3):1455-1471, June 2017
Abstract:
Helicostyla daphnis (Broderip, 1841), an arboreal edible snail endemic to Cebu, Philippines that was thought to be extinct, was discovered to be still thriving. To formulate strategies for conservation of H. daphnis, a survey of selected physicochemical parameters and local ecological knowledge (LEK) that could affect its population was conducted. On each the three sites, physicochemical parameters were measured and a standardized direct search method for snails was used. LEK was gathered among fifteen snail-hunting experts. Snail total abundance significantly varied across sites in the dry season (p=0.006), being highest at Site 1(private property), and least in at Site 2 (tree plantation). Snails were found to be more abundant in the dry season than the wet (dry=306; wet=152) but significant only at Site 1. Adult snails were the most dominant among the age categories in both the dry and wet seasons. Neonates, comprising 5% of the sampled population, were found only in the wet season. Relative humidity and air temperature were the major determinants of the total abundance. However LEK gathered pointed out that overharvesting and habitat destruction could be major contributors as well. Ficus leucantatoma, Buchananiaar borescens and Artocarpus heterophyllus are the vegetation most prefered by H. daphnis, according to LEK.
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Article title: Assessment of the Water Quality of Buhisan, Bulacao and Lahug Rivers, Cebu, Philippines Using Fecal and Total Coliform as Indicators
Authors: Eukene Bensig , Mary Joyce Flores and Fleurdeliz Maglangit
Publication title: Current World Environment 9(3):570-576, December 2014
Abstract:
This study was conducted to evaluate and compare the water quality of Buhisan, Bulacao and Lahug rivers in Cebu, Philippines using coliforms as indicators. Monthly sampling started from November 2011 to April 2012 in the upstream, midstream and downstream stations. The multiple tube fermentation technique was used for the analysis of coli forms. High total and fecal coli form counts were observed in the three rivers from February to April, but the difference in values across time was not significant. Fecal coli form counts of Buhisan and Bulacao rivers differed significantly across sampling stations. This was most likely due to the low fecal coli form (FC) values in the upstream compared with the midstream and downstream. The generally high FC and TC levels throughout the sampling period confirmed the presence of fecal pollution in the rivers. Organic pollution and the presence of coli forms could be related to the accumulation of waste water due to high impact human activities across the river networks. It is therefore recommended to conduct an inventory and monitor non-point sources of water pollution, establish waste water treatment measures and enforce policies for river protection.
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Article title: Fecal and Coliform Levels as Indicative Factors in Deteriorationof the Water Quality of Lahug River, Cebu City, Philippines
Authors: Eukene O. Bensig, Mary Joyce Lapa Flores, Fleurdeliz Maglangit
Publication title: IAMURE International Journal of Ecology and Conservation 10(1), October 2014
Abstract:
The use of surface waters such as rivers for domestic, agricultural andindustrial purposes have made them vulnerable to pollution leading to impairedwater quality. The water quality of Lahug River in Cebu City was evaluated usingcoliforms as indicators, in relation with physicochemical parameters such as biological oxygen demand (BOD), conductivity, dissolved oxygen (DO), nitrate,pH, phosphate, salinity, temperature, total dissolved solids (TDS) and totalsuspended solids (TSS). Sampling was done once a month from November 2011to April 2012 in three stations covering the upstream, midstream and downstream.The multiple tube fermentation technique was used for the analysis of coliforms.The level of these indicator bacteria increased from the upstream towards thelower reaches of the river especially in the months of February to April; however,the difference in values across time was not significant. This implies that therewas a continuous fecal pollution in the river. There were no statistically significantcorrelations between FCs and TCs with the physicochemical parameters. Anegative relationship was observed among FCs and TCs with pH, TSS, DOand nitrate (p>0.05). These results suggest the presence of sewage and organicpollutants in the river. Keywords: Aquatic Ecology, water quality, coliform, physicochemical parameters,experimental design, Philippines
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Article title: An Assessment of the Physicochemical Parameters of Mananga River, Cebu, Philippines
Authors: Mary Joyce Lapa Flores
Publication title: IAMURE International Journal of Ecology and Conservation 4:34-61, October 2012
Abstract:
The Mananga River today is a source of potable water to meet the demands of a fast growing Cebu metropolis. The physicochemical parameters of Mananga River were studied to assess its water quality status. Six sample collections were done from February to December 2006 in 3 monitoring stations covering the upstream (S1), midstream (S2) and downstream (S3) of Mananga River. Results showed significant spatial variation (p<0.05) in the studied physicochemical parameters except for alkalinity, total phosphates and nitrate-nitrogen (NO3-N). Significant temporal variation (p<0.05) was also observed for the factors except for stream width, biological oxygen demand (BOD5) and total suspended solids (TSS). Flow velocity showed significant positive correlation with discharge, pH, DO and NO3-N, and negative correlation with water temperature and TSS. Water temperature correlated negatively with DO and pH, and positively with TSS, with the latter showing a positive correlation with BOD5. The results implied that water currents play a major role in the distribution of dissolved substances and the suspension of sediments. Water quality of the studied segments of Mananga River progressively decreased downstream and was more pronounced during the dry periods. Results also indicated that the river was receiving loads of organic matter from natural and anthropogenic sources.
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Article title: Macroinvertebrate composition, diversity and richness in relation to the water quality status of Mananga River, Cebu, Philippines
Authors: Mary Joyce Lapa Flores and Macrina Zafaralla
Publication title: Philippines Science Letters 5(2), 2012
Abstract:
The water quality of Mananga River was assessed between February and December 2006 using selected physicochemical factors in combination with macroinvertebrate composition and diversity indices. Three sampling stations, each 100 m long, were established. Alkalinity, total phosphates and nitrate-nitrogen were similar in all sampling stations. The significant variation in stream depth, width and stream bed profile resulted in diminishing velocity but increasing discharge downstream. These physical characteristics led to increased total suspended solids, water temperature, and biological oxygen demand, but decreased pH and dissolved oxygen levels downstream. The physicochemical factors influenced the composition and diversity of macroinvertebrates in Mananga River. A total of 37 families representing 15 orders were recorded. Aquatic insects (Class Hexapoda) made up 58.6% of total abundance followed by the gastropods (Class Gastropoda) at 39.9%. The order Ephemeroptera of Hexapoda had the highest abundance (47.6% of total) and highest richness (6 families). Family Thiaridae was the most persistent and the most abundant macroinvertebrate taxa followed by Caenidae. Almost all taxa were represented in the upper stations, except for Neritidae, Grapsidae and Nereididae, which were limited to the downstream station. Macroinvertebrate richness and diversity were significantly higher in the upper stations, but there was an apparent lack of seasonal variation. Signs of increasing water quality deterioration were evident in the results of the physicochemical analyses, and validated by the diversity index where the upper stations came out as moderately polluted, and the downstream station as moderately to highly polluted.
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