Advances in Environmental Biology, 9(25) Special 2015, Pages: 32-37 AENSI Journals

Advances in Environmental Biology

ISSN-1995-0756 EISSN-1998-1066

Journal home page: http://www.aensiweb.com/AEB/

An Inventory of Anuran Species Within and Outside the Hydraulicking Mining Area

1Cordulo P. Ascaño II, 1Queenilyn B. Albutra, 1Vicenta V. Ansigbat, 2Dennis A. Mugot, 3Sherryl L., 4Pazand Cesar G. Demayo

1 Department of Environmental Science and Technology, College of Arts and Sciences, Mindanao University of Science and Technology, Cagayan de Oro, 2Institute of Arts and Sciences, Misamis Oriental State College of Agriculture and Technology, Claveria, Philippines 3 Department of Natural Sciences, Division of Environmental Science, College of Arts and Sciences, Caraga State University, Butuan City, Philippines 4Department of Biological Sciences, College of Science and Mathematics, Mindanao State University - Iligan Institute of Technology, Iligan City, Philippines

ARTICLE INFO ABSTRACT Article history: The decline of anuran population worldwide has been identified to be caused by several Received 3 August 2015 factors. In this study, the effect of surface gold mining on the species richness and Accepted 28 October 2015 abundance of anurans has been assessed in Brgy. Tumpagon, Cagayan de Oro City, Available online 31 October 2015 Philippines. Collections of anurans were done in the established sampling points outside and inside the mining area of Brgy. Tumpagon. Canonical Correspondence Keywords: Analysis was performed to determine the species-habitat preference and species Anuran, diversity, surface mining, survival envelope of each species based on their association to different environmental Canonical Correspondence Analysis, variables. Results revealed that anuran diversity is higher outside than the mining area. species-habitat preference Decreased in anuran diversity inside the mining area is mainly due to habitat loss and fragmentation. Majority of the anuran species have showed preference toward the forested habitat than in disturbed habitat. Conservation policy must be developed for the protection of the habitat and conservation of anuran species.

© 2015 AENSI Publisher All rights reserved. To Cite This Article: Cordulo P. Ascaño II, Queenilyn B. Albutra, Vicenta V. Ansigbat, Dennis A. Mugot, Sherryl L., Pazand Cesar G. Demayo., An Inventory of Anuran Species Within and Outside the Hydraulicking Mining Area. Adv. Environ. Biol., 9(25), 32-37, 2015

INTRODUCTION

Despite the probability of increasing rate of endemism, assessments of the world’s highlighted that population of at least 42% of known species are declining and nearly a third of the known species of amphibians are globally threatened to be extinct [1, 2] with an estimated extinction rate of over 200 times as compared to their natural background rate [3]. There appears to be no single cause for the decline of amphibian population because like other , amphibians are also assaulted by a barrage of environmental insults that frequently operate in a complex way [4]. The crisis about the decline in amphibian population is an important concern for many biologists as they have considered amphibians as excellent indicators of stressed ecosystems [5, 6] and in eco-toxicological studies [7]. According to Whittaker et al. [8], amphibians are essential members of ecosystems and their decline could possibly have diverse but not fully understood impacts on communities and ecosystems. Endemism of Philippine amphibians is high (78.5%), but is likely to increase to about 80% when more new species will be described formally following the lineage species concept [9]. Apparently, several amphibian species are yet to be discovered in unexplored of the Philippines which make the species richness of amphibians still indefinite at present time thus this study was conducted. The inventory was made within and outside an illegal mining area which the landscape was extremely damaged by the activities. It is argued that the effects of this damage include not only the erosion of land but also death of important flora and fauna of the area.

MATERIALS AND METHODS

The Study Area: Tumpagon, as shown in figure 1a, is among the hinterland barangays of Cagayan de Oro City located at 8°19'19"N and 124°28'49"E and has a total area of 11,926,596 hectares. It is bounded by Iponan river on the

Corresponding Author: Cordulo P. Ascaño II, Department of Environmental Science and Technology, College of Arts and Sciences, Mindanao University of Science and Technology, Cagayan de Oro, Philippines 33 Cordulo P. Ascaño II et al, 2015 Advances in Environmental Biology, 9(25) Special 2015, Pages: 32-37 north and west sides; the province of Lanao del Norte on the south and barangay Pigsag-an on the east. Tumpagon has abundant supply of sand and gravel as well as gold. The gold mining activity in Tumpagon, Cagayan de Oro started during the 1950’s up to the present. The method is surface mining through hydraulic technique which utilizes highly pressurized water to dislodge the surface soils to extract the gold nuggets from the area (Fig. 1b).

Fig. 1: (a) Map of the location of the study and (b) Hydraulicking method used in mining the area.

Collection of Samples and Environmental Data: A total of 4 transect lines within and outside the mining environs were established, each transect line consists of 6 lines divided into 10 sampling points (Fig. 2). The duration of sampling depends on the species population curve which is when the plateau is reached or no additional species is observed, sampling is stopped. Collections of samples were done every 6pm to 9pm (Fig. 3). Microhabitat such as bare ground, woody ground, under wood debris, in water, in trees, in stone/rocks, under a stone/rocks and in holes were searched for the possible presence of anurans (Figs. 4 and 5).

Fig. 2: Map showing the two transect lines (a) within and (b) outside the mining area.

Fig. 3: Field collection method (a) in small ponds and crevices (b) field and (c) traps.

Fig. 4: Natural habitats of anuran outside the mining area (a) stream (b) mountain side (c) plants (d) stones (e) below the trees and water drainage. 34 Cordulo P. Ascaño II et al, 2015 Advances in Environmental Biology, 9(25) Special 2015, Pages: 32-37

Fig. 5: Habitats of anuran within the mining area (a) hydraulicked area (b) stones and gravels (c) grasslands (d) ponds.

A total of 4 transects within and outside the mining environs were established. In every sampling station, 6 (100-meter) transects were laid, cutting across varied habitat types. This sampling was done to ensure representativeness of anuran species in different habitat types. The 100-meter transects were at least 50-meters apart from each other and were established either parallel or perpendicular to the stream. Each of the 100-meter transects was divided into ten (10) points, where visual survey and a detailed habitat assessment was conducted. Geographical Positioning System (GPS) was used to exactly determine the locations of all sampling stations.

Identification and Processing of Samples: Photographic guides and taxonomic literature on Philippine anurans were used to identify the samples collected. Morphometric measurements such as head length (HL), head breath (HB), snout length (SL), eye diameter (ED), tympanum distance (TD), snout-vent length (SVL), tibial length (TL), hind leg (HL) were obtained using vernier caliper while the body weight was determined using Pesola spring balance. Captured specimens were identified and tagged prior to their release to avoid recounting of the same individuals. Two voucher specimens especially those unidentified species were preserved using 70% ethyl alcohol for 24 hours and then transferred to 10% formaldehyde solution.

Analysis of Data: Diversity indices and Canonical Correspondence analysis (CCA) were performed using the PAST software version 2.14. The CCA scores obtained from the analysis was then used to construct a boxplot which contains information pertaining to the habitat preference and survival envelope or range of tolerance of each anuran species. RESULTS AND DISCUSSION

The identified species of anurans collected during the wet and dry seasons outside and inside the mining area of Brgy. Tumpagon, Cagayan de Oro, Philippines were classified according to its family and species

Table 1: Species Profile of Anurans Found Outside and Inside the Small Scale Gold Mining Area of Brgy. Tumpagon, Cagayan de Oro, Philippines. Conservation Distribution Family Scientific name Common name Status Status Bufonidae Rhinella marina Cane Toad Least Concern Introduced Philippine Ceratobatrachidae Platymantis rabori Rabori's Forest Vulnerable Endemic Asian Brackish Water Frog / Dicroglossidae Fejervarya cancrivora Least Concern Resident Crab-eating Frog Dicroglossidae Common Pond Frog Least Concern Resident Philippine Dicroglossidae Limnonectes leytensis Swamp Frog Least Concern Endemic Dicroglossidae Limnonectes magnus Philippine Giant Frog Least Concern Data Deficient Megrophyidae Megophrys montana Horn Frog Least Concern Data Deficient Mindanao Horned Frog / Mindanao Megrophyidae Megophrys stejnegeri Southeast Asian Horned Vulnerable Endemic Toad Black-spotted Narrow-mouth Microhylidae Kalophrynus pleurostigma Least Concern Resident Frog Slender-digit Chorus Frog / Philippine Microhylidae Kaloula picta Painted Narrow-mouthed Least Concern Endemic Frog Ranidae erythraea Common Green Frog Least Concern Introduced Philippine Ranidae Hylarana signata Variable-backed Frog Least Concern Endemic Rhacophoridae Polypedates leucomystax Common Tree Frog Least Concern Resident

A total of 13 species of anurans (shown in figure 2) that belong to 7 families were identified in the study area; species under the family Dicroglossidae is the most common. In terms of the distribution status, 4 Philippine endemic species: P. rabori, L leytensis, K. picta and H. signata and 1 Mindanao endemic species, 35 Cordulo P. Ascaño II et al, 2015 Advances in Environmental Biology, 9(25) Special 2015, Pages: 32-37 the M. stejnegeri were identified. Of these endemic species, P. rabori (Philippine endemic) and M. stejnegeri (Mindanao endemic) are now considered vulnerable while the rest of anuran species collected including those non-endemic species are considered least concern.

Fig. 6: Species Composition of Anuran Species Found Inside and Outside the Mining Area of Brgy. Tumpagon, Cagayan de Oro City, Philippines. (Legend: a – F. cancrivora, b – F. limnocharis, c – H. erythraea, d – H. signata, e – K. pleurostigma, f – K. picta, g – L. leytensis, h – L. magnus, i – M. montana, j – M. stejnegeri, k – P. rabori, l – P. leucomystax, m – R. marina).

The abundance of anurans species varies depending on the season and area it was collected (Table 2), but in general, P. leucomystax, R. marina and F. cancrivora are considered the most abundant anurans in the entire study area. There are 7 anuran species namely: F. cancrivora, F. limnocharis, K. pleurostigma, K. picta, M. montana, P. leucomystax and R. marina found to be more abundant during the dry season than in the wet season. Between the 2 sampling areas, there are certain species that are found exclusively outside the mining area which include H. erythraea, M. stejnegeri, P. rabori, K. pleurostigma and M. montana. The first 3 anuran species were found only during the wet season while the latter 2 species were found in both seasons but are more abundant during the dry season (Fig. 3). In general, the abundance of all anuran species is greater outside the mining area except for the K. picta and R. marina which are more abundant inside the mining area as compared to the outside. Lastly, all 13 identified species of anurans identified in this study were all found outside the mining area during the wet season.

Table 2: Species Abundance of Anuran Species Found Outside and Inside the Small Scale Gold Mining Area of Brgy. Tumpagon, Cagayan de Oro, Philippines collected during the wet and dry seasons. Outside Mining Area Inside Mining Area Anuran Species Overall Wet Season Dry Season Total Wet Season Dry Season Total F. cancrivora 25 67 92 2 12 14 106 F. limnocharis 7 18 25 1 3 4 29 H. erythraea 23 0 23 0 0 0 23 H. signata 14 6 20 5 0 5 25 K. pleurostigma 1 6 7 0 0 0 7 K. picta 2 22 24 0 47 47 71 L. leytensis 19 8 27 2 2 4 31 L. magnus 40 2 42 8 3 11 53 M. montana 1 7 8 0 0 0 8 M. stejnegeri 1 0 1 0 0 0 1 P. rabori 2 0 2 0 0 0 2 P. leucomystax 25 48 73 12 26 38 111 R. marina 12 25 37 36 35 71 108 TOTAL 172 209 381 66 128 194 575

Fig. 7: Seriation showing the similarities and differences in the transect areas based on the presence and absence of anuran species in the areas. 36 Cordulo P. Ascaño II et al, 2015 Advances in Environmental Biology, 9(25) Special 2015, Pages: 32-37

Species richness and abundance of Anurans is higher outside than inside the mining area. Species dominance inside the mining area is also higher due to high abundance of 3 anuran species namely, R. marina, K. picta and P. leucomystax relative to other species. The outside mining area of the village of Tumpagon, Cagayan de Oro City can be considered therefore more diverse compared to the inside mining area (Table 3).

Table 3: Diversity Indices of Anuran Species Found Outside and Inside the Small Scale Gold Mining Area of Tumpagon, Cagayan de Oro, Philippines. Outside Mining Area Inside Mining Area Wet Dry Diversity Indices Wet Season Dry Season Total Wet Season Dry Season Total Season Season Taxa_S 13 10 13 7 7 8 13 10 Individuals 172 209 381 66 128 194 238 337 Dominance_D 0.1399 0.1926 0.1371 0.3531 0.261 0.2409 0.1432 0.1828 Simpson_1-D 0.8601 0.8074 0.8629 0.6469 0.739 0.7591 0.8568 0.8172 Shannon_H 2.126 1.892 2.192 1.367 1.509 1.637 2.087 1.869 Evenness_e^H/S 0.6446 0.6631 0.6884 0.5606 0.6461 0.6428 0.6202 0.648

The current study clearly show that anuran diversity is lower inside when compared to the outside of the mining area. This can be attributed to the destruction of their habitat since the miners in the village of Tumpagon utilizes surface mining that strips off the soil and vegetation in the area to expose the underlying deposits of gold. The illegal practice of mining has des not only destroyed the landscape of the area where most of its vegetation has been removed, but it has also brought heavy siltation in the nearby river destroying the breeding ground of some species. Slash-and-burn system or ‘kaingin’ was also observed in the area which can also contribute to the decline in the population and diversity of anurans. Harvesting of for human consumption was also done by some residents but this action may not be viewed as a major since the abundance of common edible anuran species such as F. cancrivora and L. magnus still remains high. Habitat destruction, fragmentation and conversion are major causes of the dwindling of diversity [8, 10, 11, 12, 13]. Habitat loss and fragmentation can substantially reduce the abilities of juvenile amphibians to disperse across landscapes and the resulting reductions in post-metamorphic survival and population connectivity can threaten viability [11]. Amphibian populations may easily become isolated within a fragmented landscape because amphibians have low agility, high philopatry, and often find the matrix environment inhospitable [10]. Although some amphibians are able to thrive in urbanized or agricultural areas, many species still require undisturbed or relatively undisturbed habitat for survival [8]. Many forest-dependent species have been shown to be detrimentally affected by habitat loss and degradation, and there are cases of species that has gone extinct locally when forest fragments are too small to support viable populations [14]. Furthermore, according to Bell and Donnelly [15], rare species, species with low dispersal abilities, large area requirements, low fecundity, low population densities, abundance or high population variability, habitat and food specialists are the ones mostly affected by habitat loss and fragmentation.

Conclusion: The results of this study revealed that the illegal hydraulic mining activities in the village of Tumpagon in Cagayan de Oro City have negative impact on the diversity of anurans in the area. Comparison between 2 areas showed that the inside mining area is less diverse in anuran species as compared to the outside mining area. The species richness and abundance of anuran species is lower inside the mining area. Seasonal variation in anuran diversity was also noted in the study area wherein anurans have higher diversity during the wet season than in dry season. Habitat loss and fragmentation are the main identified reasons for the decreased diversity of anurans inside the mining area. While there are species that can survive in disturbed area, more anuran species are still dependent on undisturbed or forested area for survival thus actions must be taken for the conservation of the forested habitat.

ACKNOWLEDGEMENT

The researchers gratefully acknowledge the following agencies for their full support to this study: DOST- PCIEERD for research funding; the Tumpagon Barangay Council for providing security measures and valuable assistance to the group during the duration of this study; the LGU- CLENRO of Cagayan de Oro City for the favorable endorsement to conduct this study and for providing the relevant baseline data.

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