Intermediate metrics of translocation success are useful for long-lived, slow to mature species where survival and reproduction happen over decades. With fewer than 150 individuals in the wild, the... Show moreIntermediate metrics of translocation success are useful for long-lived, slow to mature species where survival and reproduction happen over decades. With fewer than 150 individuals in the wild, the Critically Endangered Philippine crocodile (Crocodylus mindorensis) is one of the most threatened species on Earth. This study presents the first analysis of diet and body condition of wild Philippine crocodiles and headstarted (i.e. captive-reared) individuals released into the wild over the last decade, and uses these results to show how diet and body condition can be pertinent intermediate metrics of translocation success. Analyses of stomach contents revealed 17 different aquatic and terrestrial invertebrate and vertebrate prey species. Interestingly, 70% of Philippine crocodiles showed snails to be the predominent prey type, followed by fish (36.7%), birds (33.3%) and reptiles (33.3%). More than 50% of crocodiles consumed the invasive golden apple snail, a leading agricultural pest. Regardless of crocodile history (wild vs. headstarted) or size class (juvenile vs. adult), no evidence was found for dietary differences in percentage occurrence, percentage composition or prey diversity. Body condition was significantly higher in wild compared with headstarted individuals when analysed together in a pooled group, although neither group differed significantly from the standardized expectation, and headstarted individuals were not significantly different when body condition was derived independently for the two groups. This study provides a working example of how assessing the convergence of diet and body condition between translocated and wild individuals can provide complementary monitoring parameters to demonstrate post-release establishment of translocated crocodylians. The congruent dietary composition and comparable body condition observed in this study suggest that headstarted crocodiles adapt well following release. Crocodylus mindorensis survives in an agricultural landscape and is likely to play an ecologically important role by exploiting invasive species, reinforcing the importance of this species to local communities. Show less
Doyog, N.D.; Lumbres, R.I.C.; Weerd, M. van; Baoanan, Z.G. 2021
Forest resource monitoring of different forest types is of great importance in sustainable forest management and climate change mitigation. Monitoring the productivity of forest resources could be... Show moreForest resource monitoring of different forest types is of great importance in sustainable forest management and climate change mitigation. Monitoring the productivity of forest resources could be achieved by modeling the basic tree parameters necessary for forest growth and yield. This study was conducted to develop a height-diameter at breast height (h-d) model necessary for tree height (h) estimation since h measurement is difficult in the field, especially in dense forests, and to estimate the forest productivity of the Diguyo limestone forest within the Northern Sierra Madre Natural Park (NSMNP). The diameter at breast height (d) and h of 124 trees were measured in seven 400-m2 plots as the basis for the model development. The h-d model was developed using different non-linear models such as the Chapman-Richards (CR), exponential (EX), Korf/Lundqvist (KL), modified logistic (ML), Schnute (SC), and Weibull (WE) models. The models were evaluated using the adjusted coefficient of determination (R2 adjusted), Akaike information criterion (AIC), Bayesian information criterion (BIC), mean absolute error (MAE), root mean square error (RMSE), percentage root mean squared error (PRMSE), and root mean squared percentage error (RMSPE). The performance of the species-specific allometric models and the generic models were compared for the biomass productivity of the limestone forest. Results showed that the CR h-d model performed best with MAE, RMSE, PRMSE, RMSPE, R2 adjusted, AIC, and BIC values of 1.47 m, 1.74 m, 19.31%, 28.71%, 0.79, 32.46, and 36.00, respectively. The highest average predicted tree biomass and carbon stock of the Diguyo limestone forest was 112.52 ± 97.65 t/ha and 50.64 ± 43.94 tC/ha, respectively, which is lower than other karst forests in Asia. The low forest resource productivity is due to the physical condition of the forest aggravated by natural and anthropogenic disturbances, thereby needing immediate attention to achieve forest sustainability. Show less
Taggueg, J.B.; Guzman Jr., L.S.; Soriano, L.S.; Acay, J.T.; Weerd, M. van 2019
Since 2011, the Faculty of Social Sciences (FSW) and the Institute of Environmental Sciences (CML) of Leiden University, in cooperation with Isabela State University and the Mabuwaya Foundation in... Show moreSince 2011, the Faculty of Social Sciences (FSW) and the Institute of Environmental Sciences (CML) of Leiden University, in cooperation with Isabela State University and the Mabuwaya Foundation in the Philippines organize an annual month–long international, interdisciplinary course on sustainable development, water issues and water management in the Cagayan River basin in Northeast Luzon in the Philippines. Thirty students participate in this course, 15 through Leiden University and 15 through Isabela State University. The students are enrolled in different studies, encompassing social, natural and applied sciences. The annual report contains background information, all student reports and the online blog that the students maintained during the course. Show less
Groffen, J.; Ploeg, J. van der; Telan, S.P.; Weerd, M. van 2018
Little is known about the ecology and diet of Varanus bitatawa, a recently discovered monitor lizard endemic to the Sierra Madre Mountains of Northern Luzon. Here we present data that show that it... Show moreLittle is known about the ecology and diet of Varanus bitatawa, a recently discovered monitor lizard endemic to the Sierra Madre Mountains of Northern Luzon. Here we present data that show that it has a seasonal omnivorous diet comparable to its southern congener Varanus olivaceus. Consumption of fruits from Pandanus sp., Canarium sp. and Microcos stylocarpa was evident in fecal samples, from spool and line tracking observations, and from camera trap images. The frugivorous diet was supplemented with snails and insects belonging to the orders Orthoptera, Phasmatodea and Coleoptera. Habitat of V. bitatawa was studied in lowland disturbed dipterocarp forest at an elevation below 300 m. In three sampled sites basal area of dipterocarp trees ranged from 16.23 to 84.14 m2 ha-1, total tree density from 624.6 to 1021.4 trees per ha-1 and density of Pandanus from 115.15 to 222.30 trees per ha-1. Predominantly arboreal, V. bitatawa showed reliance on large sentinel trees. Of trees utilized, 47.4% were estimated at over 30 m tall with a mean circumference at breast height (CBH) of 176.28 cm and were significantly larger than the mean CBH of trees in sampled habitats. Shy and reclusive, V. bitatawa is likely to be vulnerable to disturbance. Illegal selective logging further degrades remaining habitat threatening the large dipterocarp trees on which they rely. Continued and improved protection of the forests within the Sierra Madre Mountain Range is imperative to safeguard the future of this restricted range species. Show less
Weerd, M. van; Gatan-Balbas, M.; Verheijen, J.; Mangabat, c. 2018
Since 2011, the Faculty of Social Sciences (FSW) and the Institute of Environmental Sciences (CML) of Leiden University, in cooperation with Isabela State University and the Mabuwaya Foundation in... Show moreSince 2011, the Faculty of Social Sciences (FSW) and the Institute of Environmental Sciences (CML) of Leiden University, in cooperation with Isabela State University and the Mabuwaya Foundation in the Philippines organize an annual month–long international, interdisciplinary course on sustainable development, water issues and water management in the Cagayan River basin in Northeast Luzon in the Philippines. Thirty students participate in this course, 15 through Leiden University and 15 through Isabela State University. The students are enrolled in different studies, encompassing social, natural and applied sciences. The annual report contains background information, all student reports and the online blog that the students maintained during the course. Show less
Weerd, M. van; Gatan-Balbas, M.; Hagen, R.; Servitillo, J. 2017
Since 2011, the Faculty of Social Sciences (FSW) and the Institute of Environmental Sciences (CML) of Leiden University, in cooperation with Isabela State University and the Mabuwaya Foundation in... Show moreSince 2011, the Faculty of Social Sciences (FSW) and the Institute of Environmental Sciences (CML) of Leiden University, in cooperation with Isabela State University and the Mabuwaya Foundation in the Philippines organize an annual month–long international, interdisciplinary course on sustainable development, water issues and water management in the Cagayan River basin in Northeast Luzon in the Philippines. Thirty students participate in this course, 15 through Leiden University and 15 through Isabela State University. The students are enrolled in different studies, encompassing social, natural and applied sciences. The annual report contains background information, all student reports and the online blog that the students maintained during the course. Show less
Ploeg, J. van der; Vermeersch, L.; Rodriguez, D.; Balbas, M.; Weerd, M. van 2017
This paper describes the efforts to establish a network of community-conserved areas in the municipality of San Mariano on Luzon, with the dual aim to protect the Philippine crocodile and to... Show moreThis paper describes the efforts to establish a network of community-conserved areas in the municipality of San Mariano on Luzon, with the dual aim to protect the Philippine crocodile and to improve inland fisheries. The necessary steps to establish a community-conserved area are summarized, and their sustainability assessed. The importance of local leadership and democratic decision-making processes in the design of community-based conservation measures is highlighted, and it is argued that implicit cultural values, such as hospitality and respect, are often a more important motivation for rural communities to protect aquatic resources than explicit concerns about food security and livelihoods. Show less
Law, S.J.; Kort, S.R. de; Bennett, D.; Weerd, M. van 2016
The newly described Varanus bitatawa is a large, frugivorous, monitor lizard endemic to the northern Sierra Madre mountain range in Luzon, Philippines. This study presents the first description of... Show moreThe newly described Varanus bitatawa is a large, frugivorous, monitor lizard endemic to the northern Sierra Madre mountain range in Luzon, Philippines. This study presents the first description of its ecology from tracking and camera trapping. We captured five adult lizards weighing 1.0-5.1 kg with snout-vent lengths (SVL) from 40-66 cm and total lengths from 100-164 cm. Activity areas were non-overlapping with a mean of 12,400 m(2); males (23,300 m(2)) had larger activity areas than females (5,200 m(2)). Capture and camera trap records indicate that lizards move most frequently between 1000 and 1500. Movements were characterized by straight line distances between trees with a mean distance travelled between trees of 79 m. Mean daily distance covered was 176 m with larger distances covered by males (228 m vs 142 m for females). Show less
Ploeg, J. van der; Aquino, D.M.; Minter, T.; Weerd, M. van 2016
The legalisation of the customary land rights of rural communities is currently actively promoted as a strategy for conserving biodiversity. There is, however, little empirical information on the... Show moreThe legalisation of the customary land rights of rural communities is currently actively promoted as a strategy for conserving biodiversity. There is, however, little empirical information on the conservation outcomes of these tenure reforms. In this paper, we describe four conservation projects that specifically aimed to formalise land rights in the Philippines, a country widely seen as a model for the devolution of control over natural resources to rural communities. We demonstrate that these legalistic interventions are based on flawed assumptions, on: 1) the capacity of the state to enforce tenure; 2) the characteristics of customary land rights; and 3) the causal links between legal entitlements and sustainable natural resource management. As a result, these state-led tenure reforms actually aggravate tenure insecurity on the ground, and ultimately fail to improve natural resource management. Show less
Weerd, M. van; Taggueg, J.; Luning, S.; Gatan-Balbas, M.; Servitillo, J.; Persoon, G. 2016
Since 2011, the Faculty of Social Sciences (FSW) and the Institute of Environmental Sciences (CML) of Leiden University, in cooperation with Isabela State University and the Mabuwaya Foundation in... Show moreSince 2011, the Faculty of Social Sciences (FSW) and the Institute of Environmental Sciences (CML) of Leiden University, in cooperation with Isabela State University and the Mabuwaya Foundation in the Philippines organize an annual month–long international, interdisciplinary course on sustainable development, water issues and water management in the Cagayan River basin in Northeast Luzon in the Philippines. Thirty students participate in this course, 15 through Leiden University and 15 through Isabela State University. The students are enrolled in different studies, encompassing social, natural and applied sciences. The annual report contains background information, all student reports and the online blog that the students maintained during the course Show less
Cureg, M.C.; Bagunu, A.M.; Weerd, M. van; Balbas, M.G.; Soler, D.; Ploeg, J. van der 2016
Since 2011, the Faculty of Social Sciences (FSW) and the Institute of Environmental Sciences (CML) of Leiden University, in cooperation with Isabela State University and the Mabuwaya Foundation in... Show moreSince 2011, the Faculty of Social Sciences (FSW) and the Institute of Environmental Sciences (CML) of Leiden University, in cooperation with Isabela State University and the Mabuwaya Foundation in the Philippines organize an annual month–long international, interdisciplinary field course on sustainable development, water issues and water management in the Cagayan River basin and Sierra Madre Mountains in Northeast Luzon in the Philippines. Thirty students usually participate in this course, 15 through Leiden University and 15 through Isabela State University. The students are enrolled in different studies, encompassing social, natural and applied sciences. The annual report contains background information about that year’s course, all student reports and the online blog that the students maintained during the course. Show less
Cureg, M.C.; Bagunu, A.M.; Balbas, M.G.; Soler, D.; Weerd, M. van; Van der Ploeg, J. 2015
Since 2011, the Faculty of Social Sciences (FSW) and the Institute of Environmental Sciences (CML) of Leiden University, in cooperation with Isabela State University and the Mabuwaya Foundation in... Show moreSince 2011, the Faculty of Social Sciences (FSW) and the Institute of Environmental Sciences (CML) of Leiden University, in cooperation with Isabela State University and the Mabuwaya Foundation in the Philippines organize an annual month–long international, interdisciplinary field course on sustainable development, water issues and water management in the Cagayan River basin and Sierra Madre Mountains in Northeast Luzon in the Philippines. Thirty students usually participate in this course, 15 through Leiden University and 15 through Isabela State University. The students are enrolled in different studies, encompassing social, natural and applied sciences. The annual report contains background information about that year’s course, all student reports and the online blog that the students maintained during the course. Show less
