Present Status of Tamaraw (Bubalus mindorensis) in Mt. Aruyan, Mindoro, Philippines

Matsubayashi, Hisashi; Boyles, Rodel M.; Salac, Ronilo L.; Barrio, Arnel Del; Cruz, Libertado C.; Garcia, Reynor A.; Ishihara, S.; Kanai, Yoshikatsu

doi:10.3759/tropics.18.167

Cited by 6 publications

(4 citation statements)

References 3 publications

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“…The Philippine government prohibited the hunting of tamaraw as early as 1936 but poaching did not stop completely. A field survey in the Mount Aruyan–Malati Tamaraw Reservation revealed that few tamaraw remain there, and they are threatened by poaching and land-use conflicts with the Mangyan people (Matsubayashi et al, 2010). A similar field survey at Mount Calavite Wildlife Sanctuary in 2010 failed to find evidence of the presence of tamaraw (S. Ishihara et al, unpubl.…”

Section: Discussionmentioning

confidence: 99%

Long-term community-based monitoring of tamaraw Bubalus mindorensis on Mindoro Island, Philippines

Ishihara

Boyles²,

Matsubayashi

et al. 2014

Oryx

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The Critically Endangered tamaraw Bubalus mindorensis is endemic to Mindoro Island, Philippines, and little is known of its ecology. During 2006-2011 we used community-based monitoring to examine the population status and ecology of tamaraw in the species' core habitat of Mount Iglit-Baco National Park. Each year, for 5 consecutive days at the end of the dry season, trained local volunteers and rangers or project staff were allocated to 18 vantage points in the study area (c. 160 km 2 ). Tamaraw were categorized as adult (. 5 years), juvenile (2-5 years) or calf (, 2 years), and sexed when possible. During the study period the population was 239-314 (mean 271), with no significant fluctuations in age structure (percentage of adults, juveniles and calves: 57.8, 21.0 and 21.3%) or estimated adult female reproductive rates (29.1%). In adults, but not in juveniles, the sex ratio was biased towards females (1 : 1.86, P , 0.01). Bulls were often solitary (32.2% of sightings), whereas the majority of cows (94.7%) formed small groups of 2-12 individuals of different ages, with or without bulls (53.4 and 46.6%, respectively). These results demonstrate that the population remained relatively stable, maintaining a constant age structure and reproductive rate, and that long-term community-based monitoring was effective for quantitative characterization of the tamaraw's social behaviour, which is critical for conservation and management of the species.

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Section: Discussionmentioning

confidence: 99%

Long-term community-based monitoring of tamaraw Bubalus mindorensis on Mindoro Island, Philippines

Ishihara

Boyles²,

Matsubayashi

et al. 2014

Oryx

Self Cite

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“…Despite being officially protected by law since 1954, as well as the creation of the sizeable Mounts Iglit‐Baco Natural Park (hereafter noted MIBNP) protected area in 1970 to protect its key habitat (Maala, 2001), tamaraw range has decreased substantially over the last decades. As a consequence, the tamaraw is now found in a few isolated populations scattered across Mindoro, with MIBNP holding the largest population (Matsubayashi et al ., 2010; Wilson & Mittermeier, 2011; Long et al ., 2018), restricted to a single location <3000 ha hereafter referred to as the core zone of monitoring (CZM).…”

Section: Introductionmentioning

confidence: 99%

Cast away on Mindoro island: lack of space limits population growth of the endangered tamaraw

Bonenfant

Rutschmann

Burton

et al. 2023

Animal Conservation

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Endangered species, despite often living at low population densities, may undergo unexpected density‐dependent feedbacks in the case of successful recovery or marked reduction in range. Because density‐dependence dynamics can increase risk of extinction, these effects can hamper conservation efforts. In this study, we analyze the dynamics of the largest population of the tamaraw Bubalus mindorensis, a critically endangered ungulate species endemic to Mindoro island, Philippines. The population is located within a <3000 ha area in Mounts Iglit‐Baco Natural Park, with limited expansion possibilities. We took advantage of a 22 year time series of tamaraw counts to estimate annual population growth rate and possible density‐dependence, accounting for sampling errors in the counts. The tamaraw population has been increasing at an average rate of +5% per year, as would be expected given its protected status by law. Population growth showed strong spatial structuring, with a population growth close to +10% in the core area of protection, and a reduction of abundance of −5% at the periphery of its range, inside the protected area. This range constriction is concerning because our best population dynamics model suggests significant negative density‐dependence (Bayes factor = 0.9). The contraction of tamaraw range is likely caused by anthropogenic pressures forcing the species to live at relatively high densities in the core zone where protection is most effective, creating source‐sink dynamics. Our study highlights the fact that, despite the continuous population growth over the last two decades, the long‐term viability of the Mounts Iglit‐Baco Natural Park tamaraw population remains uncertain.

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“…Originally found across the whole island of Mindoro with a gross estimate of 10,000 individuals in 1900 (Long et al 2018), the tamaraw has suffered from intensive land conversion for agriculture and logging industry, trophy hunting, disease outbreaks spread out by domestic cattle (Maala 2001), and traditional hunting conducted by upland indigenous communities who share their living space with the large herbivore (Long et al 2018). As a consequence, the species is now found in a few isolated populations scattered across Mindoro, with MIBNP hosting the largest number (Matsubayashi et al 2010;Wilson & Mittermeier 2011;Long et al 2018). The MIBNP tamaraw population has been restricted to one location of less than <3,000 ha in 2018, that we referred to as the Core Zone of the Monitoring (CZM, see Fig.…”

Section: Introductionmentioning

confidence: 99%

“…Despite being officially protected by law since 1954, as well as the creation of the sizeable Mounts Iglit-Baco Natural Park (MIBNP) protected area in 1970 to protect its key habitat (Maala 2001), tamaraw range has decreased substantially over the last decades. As a consequence, the tamaraw is now found in a few isolated populations scattered across Mindoro, with MIBNP holding the largest population (Matsubayashi et al 2010; Wilson & Mittermeier 2011; Long et al 2018), restricted to a single location <3 000 ha hereafter referred to as the core zone of monitoring (CZM).…”

Section: Introductionmentioning

confidence: 99%

Cast away on Mindoro island: lack of space limits population growth of the endangered tamaraw (Bubalus mindorensis)

Bonenfant

Rutschmann

Burton

et al. 2020

Preprint

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Endangered species, despite living at low population density, may undergo 2 density-dependent feed-backs in case of successful recovery or marked reduction in range. When at work, density-dependence dynamics increases extinction risks 4 and hamper conservation efforts. The last population of the critically endangered tamaraw (Bubalus mindorensis) lives on a < 3, 000ha in Mounts Iglit-Baco 6 Natural Park (MIBNP) with very limited expansion possibilities. Tamaraw abundance has been monitored on a yearly basis from animal counts by 8 Philippine authorities since the year 2000. Consistent with its protected status by law, the MIBNP tamaraw population has been increasing in size at an average 10 rate of +6% per year, which we found to be relatively low compared to other similar-sized Bovinea species. Population growth was strikingly spatially 12 structured within MIBNP with a population growth close to +16% in the core area of protection, while a reduction of abundance of −27% was measured at the 14 periphery of the species range inside MIBNP. Highly concerning is the fact that the annual population growth rate progressively decreased significantly over the 16 years since 2008, which we interpreted as an evidence of density-dependence. This isolated tamaraw population is currently experiencing a contraction of its 18 range at MIBNP, likely caused by anthropogenic pressures forcing large herbivores to live at relatively high density in the core zone of the monitoring 20 where protection is most effective. Our study highlights that beyond the encouraging results of a continuous growth over the last two decades, the 22 MIBNP tamaraw population remains subject to uncertainty of its long term viability. 24 14 is a decrease of the population growth at low population abundance (i.e. demographic component, see Stephens et al. (1999)). On the other hand, 16 classical density-dependent effects, the decrease of the population growth rate with density (Nicholson 1933), on population dynamics are often overlooked in 18 conservation because they are a priori expected to occur at high population abundance. Increasing density in populations of endangered species may, 20 however, occur incidentally following a range reduction caused by habitat loss or successful protection measures, and in turn triggers undesirable ecological 22 consequences for its conservation.Density-dependence is a pervasive demographic responses among large

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Present Status of Tamaraw (Bubalus mindorensis) in Mt. Aruyan, Mindoro, Philippines

Abstract: t i o n . T h e s e r e s u l t s i n d i c a t e t h a t t h e conser vation of tamaraw in the

Cited by 6 publications

References 3 publications

Long-term community-based monitoring of tamaraw Bubalus mindorensis on Mindoro Island, Philippines

Long-term community-based monitoring of tamaraw Bubalus mindorensis on Mindoro Island, Philippines

Cast away on Mindoro island: lack of space limits population growth of the endangered tamaraw

Cast away on Mindoro island: lack of space limits population growth of the endangered tamaraw (Bubalus mindorensis)

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