Mary Rose C. Posa

National University of Singapore, Tumasik, Singapore

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Publications (19)127.48 Total impact

  • Lahiru S. Wijedasa · Mary Rose C. Posa · Gopalasamy R. Clements ·

    Nature 11/2015; 527(7578):305-305. DOI:10.1038/527305b · 41.46 Impact Factor
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    ABSTRACT: Orangutans (genus Pongo) are the largest arboreal mammals, but Bornean orangutans (P. pygmaeus spp.) also spend time on the ground. Here, we investigate ground use among orangutans using 32,000 hr of direct focal animal observations from a well-habituated wild population of Bornean orangutans (P. p. wurmbii) living in a closed-canopy swamp forest at Tuanan, Central Kalimantan, Indonesia. Ground use did not change with increasing observation time of well-habituated individuals, suggesting it was not an artifact of observer presence. Flanged males spent the most time on the ground (ca. 5% of active time), weaned immatures the least (around 1%). Females and immatures descended mainly to feed, especially on termites, whereas flanged males traveled more while on the ground. Flanged males may travel more inconspicuously, and perhaps also faster, when moving on the ground. In addition, orangutans engaged in ground-specific behavior, including drinking from and bathing in swamp pools. Supplementary records from 20 ground-level camera traps, totaling 3986 trap days, confirmed the observed age-sex biases in ground use at Tuanan. We conclude that ground use is a natural part of the Bornean orangutan behavioral repertoire, however it remains unclear to what extent food scarcity and canopy structure explain population differences in ground use. Am. J. Primatol. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.
    American Journal of Primatology 08/2015; DOI:10.1002/ajp.22460 · 2.44 Impact Factor
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    ABSTRACT: Conservation science needs to engage the general public to ensure successful conservation interventions. Although online technologies such as Twitter and Facebook offer new opportunities to accelerate communication between conservation scientists and the online public, factors influencing the spread of conservation news in online media are not well understood. We explored transmission of conservation research through online news articles with generalized linear mixed-effects models and an information theoretic approach. In particular, we assessed differences in the frequency conservation research is featured on online news sites and the impact of online conservation news content and delivery on Facebook likes and shares and Twitter tweets. Five percent of articles in conservation journals are reported in online news, and the probability of reporting depended on the journal. There was weak evidence that articles on climate change and mammals were more likely to be featured. Online news articles about charismatic mammals with illustrations were more likely to be shared or liked on Facebook and Twitter, but the effect of news sites was much larger. These results suggest journals have the greatest impact on which conservation research is featured and that news site has the greatest impact on how popular an online article will be on Facebook and Twitter.
    Conservation Biology 01/2015; 29(3). DOI:10.1111/cobi.12455 · 4.17 Impact Factor
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    Petah A. Low · Katerina Sam · Clare McArthur · Mary Rose C. Posa · Dieter F. Hochuli ·
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    ABSTRACT: The use of model caterpillars to assess relative rates of predation has risen in popularity in recent years. Among the various benefits of the technique is its capacity to provide information on the identity of attackers through the impressions left in the modelling clay from which the model prey is constructed. However, there currently exists no detailed information on how to assign attack marks to particular predators. We aimed to address this gap by collating a comprehensive reference collection of the types of marks made by different predators to serve as a guide for researchers wanting to identify the predators responsible for attacks. To determine what level of resolution in identification may be considered reliable, we also tested the consistency of predator assignments made by different individuals. We found that predator identification at a coarse taxonomic level (i.e., bird, mammal, arthropod) was reasonably consistent. In contrast, when more fine-scale identification was attempted, the level of consistency and therefore also confidence in the accuracy of an identification was dramatically reduced, reflecting the difficulty of distinguishing between attacks made not only by different arthropod groups but also by differently sized birds and mammals. We recommend that identifications be made at a coarse taxonomic level and, where possible, by multiple individuals. We also suggest that our collection of images of representative attack marks from each of the coarse predator categories, and descriptions of their defining characteristics, can serve as a guide to assist with identifications and this will be complemented by a good knowledge of the locally occurring and abundant predators.
    Entomologia Experimentalis et Applicata 06/2014; 152(2). DOI:10.1111/eea.12207 · 1.62 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 08/2012; · 0.04 Impact Factor
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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; DOI:10.1016/j.biocon.2011.12.016 · 3.76 Impact Factor
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    Land-use Intensification Effects on Biodiversity and Ways to Mitigate Them, Edited by Lindenmayer D., Young A., Cunningham S., Broad hurst L., 01/2012: pages 33-39; CSIRO Publishing., ISBN: 9780643104075
  • 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 10/2011; 144(10):2548-2556. DOI:10.1016/j.biocon.2011.07.015 · 3.76 Impact Factor
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    M.R.C. Posa · L.S. Wijedasa · R.T. Corlett ·

    BioScience 04/2011; 61:49-57. · 5.38 Impact Factor
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    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; 61(Jan 2011):49-57. DOI:10.1525/bio.2011.61.1.10 · 5.38 Impact Factor
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    ABSTRACT: Southeast Asia experiences one of the highest rates of deforestation in the tropics due to agricultural expansion, logging, habitat fragmentation and urbanization, which are expected to result in species declines and extinctions. In particular, growing global demands for food, biofuel and other commodities are driving the rapid expansion of oil palm and paper-and-pulp industries at the expense of lowland dipterocarp forests, further jeopardizing Southeast Asian forest biotas. We synthesize recent findings on the effects of land-use changes on plants, invertebrates, vertebrates and ecosystem functioning/services in Southeast Asia. We find that species richness and abundance/density of forest-dependent taxa generally declined in disturbed compared to mature forests. Species with restricted ranges and those with habitat and foraging specialization were particularly vulnerable. Forest loss also disrupted vital ecosystem services (e.g. crop pollination). Long-term studies are needed to understand biotic sustainability in regenerating and degraded forests, particularly in the context of the synergistic or additive effects of multiple agents of biodiversity loss (e.g. invasive species and climate change). The preservation of large tracts of mature forests should remain the principal conservation strategy in the tropics. In addition, reforestation and reintroductions of native species, as well as improved connectivity among forest patches could enhance the conservation value of forest remnants in human-dominated landscapes.
    Biological Conservation 10/2010; 143(10):2375-2384. DOI:10.1016/j.biocon.2009.12.029 · 3.76 Impact Factor
  • N.S. Sodhi · M.R.C. Posa · T.M. Lee · David Bickford · L.P. Koh · B.W. Brook ·
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    ABSTRACT: Cited By (since 1996):63, Export Date: 26 November 2013, Source: Scopus
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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 02/2009; 19(2):317-328. DOI:10.1007/s10531-009-9607-5 · 2.37 Impact Factor
  • Navjot S. Sodhi · Mary Rose C. Posa · Tien Ming Lee · Ian G. Warkentin ·

    The Auk 01/2009; 125(Jul 2008):511-519. DOI:10.1525/auk.2008.1708 · 1.86 Impact Factor
  • Mary Rose C. Posa · Arvin C. Diesmos · Navjot S. Sodhi · Thomas M. Brooks ·
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    ABSTRACT: The Philippines is a megabiodiversity country, but it is also often seen as a country of ecological ruin whose biodiversity is on the verge of collapse. Decades of environmental neglect have pushed ecosystems to their limit, often with deadly repercussions for the human population. Is conservation in the Philippines a lost cause? We review current conservation efforts in the Philippines, considering the actions of academics, field researchers, local communities, nongovernmental organizations, the government, and other sectors of society. Remarkably, however precarious the present situation may seem, there have been some recent positive gains and signs of hope. Although there is no room for complacency, we conclude that the diversity Of available indicators suggests that conservation in the Philippines, against many odds, shows signs of success, and thus deserves greater attention and increased investment.
    BioScience 03/2008; 58(3). DOI:10.1641/B580309 · 5.38 Impact Factor
  • Reuben Clements · Mary Rose C Posa ·

    Nature 10/2007; 449(7161):403. DOI:10.1038/449403d · 41.46 Impact Factor
  • Mary Rose C. Posa · Navjot S. Sodhi · Lian Pin 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(01):27-33. DOI:10.1017/S0266467406003671 · 0.90 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 04/2006; 129(2-129):256-270. DOI:10.1016/j.biocon.2005.10.041 · 3.76 Impact Factor
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    Navjot S. Sodhi · Mary roSe C. PoSa ·

Publication Stats

466 Citations
127.48 Total Impact Points

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  • 2007-2014
    • National University of Singapore
      • Department of Biological Sciences
      Tumasik, Singapore
  • 2006-2008
    • University of the Philippines Diliman
      • Institute of Biology
      Кесон-Сити, Metro Manila, Philippines