Mary Rose C. Posa

National University of Singapore, Singapore, Singapore

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Publications (15)68.9 Total impact

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    ABSTRACT: The unsustainable exploitation of nature by humanity has pushed many of the earth’s ecological systems to the brink of collapse. To help bring about the societal changes needed to reverse this trend, conservation biologists need to be more proactive, provocative, and purposeful in increasing environmental literacy. In this essay, we highlight different ways that scientists can engage various sectors of society and argue that passion, enthusiasm, and an understanding of the culture of human belief systems can help us to communicate effectively with a wider audience.
    Biological Conservation 02/2012; · 3.79 Impact Factor
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    M. R. C. Posa, D. A. Marques
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    ABSTRACT: The avifauna of tropical peat swamp forest has not been well documented, even though it is an extensive habitat in parts of South-East Asia. We conducted surveys using various methods at the Tuanan research station and surrounding areas in Central Kalimantan, Indonesian Borneo. These observations resulted in a list of 138 bird species and numerous noteworthy records. Although more depauperate than lowland rainforest on mineral soils, peat swamp forest is an important habitat for many threatened and Near Threatened bird species, especially habitat specialists such as Hook billed Bulbul Setornis criniger and Grey breasted Babbler Malacopteron albogulare. We also recorded in selectively logged peat swamp several high-profile globally threatened species such as Crestless Fireback Lophura erythrophthalma, Storm's Stork, Ciconia stormi, Great Slaty Woodpecker Mulleripicus pulverulentus, Black Hornbill Anthracoceros malayanus and Wrinkled Hornbill Aceros corrugatus. In view of its importance to certain species, peat swamp forest should be afforded more protection, especially in light of the recent rapid loss of this habitat to land conversion and forest fires.
    Forktail 01/2012; · 0.25 Impact Factor
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    01/2012: pages 33-39; CSIRO Publishing., ISBN: 9780643104075
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    M.R.C. Posa, L.S. Wijedasa, R.T. Corlett
    BioScience 04/2011; 61:49-57. · 5.44 Impact Factor
  • Mary Rose C. Posa, Lahiru S. Wijedasa
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    ABSTRACT: Tropical peat swamp forest is a unique ecosystem that is most extensive in Southeast Asia, where it is under enormous threat from logging, fire, and land conversion. Recent research has shown this ecosystem's significance as a global carbon store, but its value for biodiversity remains poorly understood. We review the current status and biological knowledge of tropical peat swamp forests, as well as the impacts of human disturbances. We demonstrate that these forests have distinct floral compositions, provide habitat for a considerable proportion of the region's fauna, and are important for the conservation of threatened taxa, particularly specialized freshwater fishes. However, we estimate that only 36% of the historical peat swamp forest area remains, with only 9% currently in designated protected areas. Given that peat swamp forests are more vulnerable to synergies between human disturbances than other forest ecosystems, their protection and restoration are conservation priorities that require urgent action.
    BioScience 02/2011; · 5.44 Impact Factor
  • Mary Rose C. Posa
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    ABSTRACT: Peat swamp forest is a unique wetland ecosystem covering extensive areas in Southeast Asia that has received relatively little scientific attention and is now being lost at a rapid pace. This study examines the effects of anthropogenic degradation on bird communities in disturbed peat swamp forest habitats – namely, intact logged forest, a degraded forest fragment, and non-forest regrowth – in Central Kalimantan, Indonesia. Results show that species richness was significantly higher and species composition significantly different in intact logged forest in comparison to the degraded forest fragment and non-forested area. Nectarivore and tree foliage-gleaning insectivore abundance declined outside the intact forest, while the regrowth was dominated by the yellow vented bulbul, an open country insectivore–frugivore. Surveys reveal that large intact tracts of logged peat swamp forest can harbour threatened and near threatened bird species (36% of records) and thus play a role in their conservation, especially for a few habitat specialists. Given the extent of unmanaged degraded peatlands and continuing pressure to development them, urgent conservation actions are needed to rehabilitate and protect this ecosystem.
    Biological Conservation - BIOL CONSERV. 01/2011; 144(10):2548-2556.
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    ABSTRACT: Cited By (since 1996):63, Export Date: 26 November 2013, Source: Scopus
    Biodiversity and Conservation. 01/2010; 19(2):317-328.
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    Biological Conservation 01/2010; 143:2375-2384. · 3.79 Impact Factor
  • The Auk 01/2009; · 2.40 Impact Factor
  • BioScience 01/2008; 58(3). · 5.44 Impact Factor
  • Reuben Clements, Mary Rose C Posa
    Nature 10/2007; 449(7161):403. · 38.60 Impact Factor
  • M. R. C. Posa, N. S. Sodhi, L. P. Koh
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    ABSTRACT: One possible mechanism underlying species losses in the tropics is an increase in predation due to habitat degradation. Relative levels of predation at three heights (ground. 1-1.5 m. > 5 in for nests and > 3 In for caterpillars) were compared across a gradient of disturbance in the Subic Bay Watershed Forest Reserve. Philippines over a 2-mo period. Four 750-m transects were established in each habitat type (closed-canopy forest, open-canopy forest, rural areas) where artificial nests and caterpillar models were placed within 10m-radius plots and checked after it 5-d exposure period. Nests in open-canopy forest were least predated (16.7%,). with predation in rural areas (58.3%) being higher than in closed-canopy forest (32.8%). Predation nests at 1-1.5 in was significantly lower than ground nests. General linear mixed model analysis suggested that effects of habitat type on nest predation differed among heights. Attacks on caterpillars increased with disturbance (46.1-59.4%), but height was not found to have a significant effect on predation. Markings on plasticine models. camera traps and live traps were used to establish possible predators. Shifts in predator dominance among the habitats were observed. vegetation cover, tree density and small mammal abundance were not correlated with mean predation in the transects.
    Journal of Tropical Ecology 01/2007; 23:27-33. · 1.48 Impact Factor
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    Mary Rose C. Posa, Navjot S. Sodhi
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    ABSTRACT: Despite the loss of 83% of native forests in the Philippines, little is known on the effects of this massive habitat loss and degradation on its forest biotas. This is a cause for concern because of the threat posed to the country’s large number of endemic taxa. To investigate the impacts of anthropogenic disturbance, forest birds and butterflies were surveyed in closed and open canopy forests, as well as suburban, rural and urban areas within the Subic Bay Watershed Reserve and Olongapo City in western Luzon. Measures of forest species richness and population densities for both taxa were similar in the two forest types, but showed different patterns in the other habitats. Indirect gradient analysis showed that forest bird species were positively correlated with vegetation variables (i.e., canopy cover, tree density, height to inversion and ground cover), while forest butterflies were not strongly correlated to any of the measured habitat variables. Community composition of birds in forests was distinct from those in modified habitats, while butterfly communities were more similar. A simulation showed that canopy cover of 60% or higher was required by 24 of the 26 bird species that were sensitive to canopy loss. Endemicity and nesting strata were the significant predictors of vulnerability to habitat disturbance for birds, while endemicity and larval hostplant specificity were significant for butterflies. Both taxa were negatively affected by anthropogenic disturbance but may respond to different components in the habitat (i.e., structure and resources), and thus cannot be used as surrogates of each other. Conservation of forests with contiguous canopy cover should be prioritized, and more ecological research is needed to improve the knowledge on the effects of disturbance on Philippine biodiversity.
    Biological Conservation. 01/2006;
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    Navjot S. Sodhi, Mary roSe C. PoSa
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    ABSTRACT: Southeast Asia is a region of conservation concern due to heavy losses of its native habitats. In this overview, we highlight the conservation importance of Southeast Asia by comparing its degree of species endemism and endangerment, and its rate of deforestation with other tropical regions (i.e., Meso-America, South America, and Sub-Saharan Africa). Southeast Asia contains the highest mean proportion of country-endemic bird (9%) and mammal species (11%). This region also has the highest proportion of threatened vascular plant, reptile, bird, and mammal species. Furthermore, not only is Southeast Asia’s annual deforestation rate the highest in the tropics, but it has also increased between the periods 1990–2000 and 2000–2005. This could result in projected losses of 13–85% of biodiversity in the region by 2100. Secondary habitat restoration, at least in certain countries, would allow for some amelioration of biodiversity loss and thus potentially lower the currently predicted extinction rates. Nonetheless, urgent conservation actions are needed. Conservation initiatives should include public education, sustaining livelihoods, and ways to enhance the sustainability of agriculture and increase the capacity of conservation institutions. Furthermore, these actions should be country-specific and not ignore areas heavily populated by humans, as they can also harbour high numbers of threatened species. We urge that cooperative conservation initiatives be undertaken and support (e.g., capacity-building) be given by more developed countries in the region and beyond.
    Biodiversity and Conservation 19(2):317-328. · 2.26 Impact Factor

Publication Stats

177 Citations
68.90 Total Impact Points


  • 2009–2011
    • National University of Singapore
      • Department of Biological Sciences
      Singapore, Singapore
  • 2006
    • University of the Philippines Diliman
      Кесон-Сити, National Capital Region, Philippines