Bird Abundances in Primary and Secondary Growths in Papua New Guinea: A Preliminary Assessment

Tvardíková, Kateřina

doi:10.1177/194008291000300403

Cited by 18 publications

(19 citation statements)

References 38 publications

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“…A repeated survey of rainforest birds was carried out along an elevation gradient on the slopes of Mt. Wilhelm in the Central Range of Papua New Guinea [ 29 , 30 ]. The study was completed along a 30 km long transect with eight sites, spanning from lowland floodplains at 200 m to the timberline at 3700 m. The sampling method was individual counts, which comprised surveying the bird communities at each site by point counts, mist-netting and random walks through the area.…”

Section: Methodsmentioning

confidence: 99%

Evaluating Functional Diversity: Missing Trait Data and the Importance of Species Abundance Structure and Data Transformation

Májeková¹,

Paal²,

Plowman³

et al. 2016

PLoS ONE

106

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Functional diversity (FD) is an important component of biodiversity that quantifies the difference in functional traits between organisms. However, FD studies are often limited by the availability of trait data and FD indices are sensitive to data gaps. The distribution of species abundance and trait data, and its transformation, may further affect the accuracy of indices when data is incomplete. Using an existing approach, we simulated the effects of missing trait data by gradually removing data from a plant, an ant and a bird community dataset (12, 59, and 8 plots containing 62, 297 and 238 species respectively). We ranked plots by FD values calculated from full datasets and then from our increasingly incomplete datasets and compared the ranking between the original and virtually reduced datasets to assess the accuracy of FD indices when used on datasets with increasingly missing data. Finally, we tested the accuracy of FD indices with and without data transformation, and the effect of missing trait data per plot or per the whole pool of species. FD indices became less accurate as the amount of missing data increased, with the loss of accuracy depending on the index. But, where transformation improved the normality of the trait data, FD values from incomplete datasets were more accurate than before transformation. The distribution of data and its transformation are therefore as important as data completeness and can even mitigate the effect of missing data. Since the effect of missing trait values pool-wise or plot-wise depends on the data distribution, the method should be decided case by case. Data distribution and data transformation should be given more careful consideration when designing, analysing and interpreting FD studies, especially where trait data are missing. To this end, we provide the R package “traitor” to facilitate assessments of missing trait data.

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Section: Methodsmentioning

confidence: 99%

Evaluating Functional Diversity: Missing Trait Data and the Importance of Species Abundance Structure and Data Transformation

Májeková¹,

Paal²,

Plowman³

et al. 2016

PLoS ONE

106

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“…A recent study of bird diets in Papua New Guinea showed that 61 of 98 bird species fed on ants, 47 species included ant eggs in their diet, 63 bird species fed on Lepidoptera larvae, and 39 bird species fed on adult Lepidoptera (Tvardikova 2013). Therefore, we identified butterflies and ants as important prey for birds (besides beetles and spiders).…”

Section: Methodsmentioning

confidence: 92%

“…Previous work in primary and secondary forests in Papua New Guinea (Tvardikova 2010) has demonstrated that lowland insectivorous birds and canopy frugivores are particularly sensitive to forest disturbance. Other investigators have also reported that large frugivorous and understory insectivorous birds are sensitive to habitat alteration (Stouffer and Bierregaard 1995, Sekercioglu 2002, Sekercioglu et al 2002, Kattan et al 2004, Lees and Peres 2010.…”

Section: Resumen El Efecto De La Fragmentación Del Bosque Sobre La Rmentioning

confidence: 99%

Effect of forest fragmentation on bird species richness in Papua New Guinea

et al. 2014

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Tropical forests worldwide are being fragmented at a rapid rate, causing a tremendous loss of biodiversity. Determining the impacts of forest disturbance and fragmentation on tropical biotas is therefore a central goal of conservation biology. We focused on bird communities in the interior (>100 m from forest edge) of forest fragments (300, 600, and 1200 ha) in the lowlands of Papua New Guinea and compared them with those in continuous forest. We surveyed bird communities using point counts, mist‐netting, and random walks, and measured habitat and microclimate characteristics at each site. We also surveyed leaf‐dwelling arthropods, butterflies, and ants, and obtained diet samples from birds to examine food availability and food preferences. We recorded significantly fewer bird species per point in the 300‐ha forest fragment than in other study sites. Overall, we recorded 80, 84, and 88 species, respectively, in forest fragments, and 102 in continuous forest. Frugivores (especially large frugivores) and insectivores had lower species richness in forest fragments than continuous forest. Our results did not support the food scarcity hypothesis, that is, the decline of insectivorous birds in forest fragments is caused by an impoverished invertebrate prey base. We also found no significant differences among forest fragments and continuous forest in microclimates of forest interiors. Rather, we found that microhabitats preferred by sensitive birds (i.e., 30% of species with the strongest preferences for continuous forest) were less common in forest fragments (19%–31% of points) than in continuous forest (86% of points). Our results suggest that changes in microhabitats may make forest fragments unsuitable for sensitive species. However, limited dispersal capabilities could also make some species of birds less likely to disperse and occupy fragments. In addition, impoverished food resources, size of the forest fragment, or hunting pressure could contribute to the absence of large frugivorous birds in forest fragments. The forest fragments in our study, preserved as village‐based protected areas, were not large enough to sustain the bird communities found in continuous forest. However, because these fragments still contained numerous bird species, preservation of such areas can be an important component of management strategies to conserve rainforests and birds in Papua New Guinea.

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“…Studies comparing avian species richness and community structure in SF and PF report inconsistent results. Some studies have found equivalent or higher species richness in SF compared to PF (Andrade & Rubio‐Torgler, ; Blake & Loiselle, ; Borges, ; O'Dea & Whittaker, ; Schulze & Waltert, ), while other studies report reduced species richness in SF (Barlow, Mestre et al., ; Bowman, Woinarski, Sands, Wells, & McShane, ; Gibson et al., ; Terborgh & Weske, ; Tvardíková, ). These conflicting results may stem from three key factors: the age of SF studied, the landscape context, and the responses of different avian groups to habitat change.…”

Section: Introductionmentioning

confidence: 99%

“…Studies focusing on young SF may therefore underestimate the longer‐term value of SF for bird conservation. While estimates of avian species richness in young SF are often inflated by non‐forest species, species composition in young tropical SF tends to differ from PF (Barlow, Gardner et al., ; Borges, ; Tvardíková, ). With increasing time since abandonment, both forest structure and bird communities become more similar to those of PF (Andrade & Rubio‐Torgler, ; Borges, ; Raman, ).…”

Section: Introductionmentioning

confidence: 99%

Connectivity with primary forest determines the value of secondary tropical forests for bird conservation

et al. 2019

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Species extinctions caused by the destruction and degradation of tropical primary forest may be at least partially mitigated by the expansion of regenerating secondary forest. However, the conservation value of secondary forest remains controversial, and potentially underestimated, since most previous studies have focused on young, single-aged, or isolated stands. Here, we use point-count surveys to compare tropical forest bird communities in 20-120-year-old secondary forest with primary forest stands in central Panama, with varying connectivity between secondary forest sites and extensive primary forest. We found that species richness and other metrics of ecological diversity, as well as the combined population density of all birds, reached a peak in younger (20-year-old) secondary forests and appeared to decline in older secondary forest stands. This counter-intuitive result can be explained by the greater connectivity between younger secondary forests and extensive primary forests at our study site, compared with older secondary forests that are either (a) more isolated or (b) connected to primary forests that are themselves small and isolated. Our results suggest that connectivity with extensive primary forest is a more important determinant of avian species richness and community structure than forest age, and highlight the vital contribution secondary forests can make in conserving tropical bird diversity, so long as extensive primary habitats are adjacent and spatially connected.Abstract in Spanish is available with online material. K E Y W O R D S bird communities, community structure, conservation, landscape management, land-use change, Panama, secondary forest, tropical extinction crisis S U PP O RTI N G I N FO R M ATI O N Additional supporting information may be found online in the Supporting Information section at the end of the article. How to cite this article: Mayhew RJ, Tobias JA, Bunnefeld L, Dent DH. Connectivity with primary forest determines the value of secondary tropical forests for bird conservation.

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Bird Abundances in Primary and Secondary Growths in Papua New Guinea: A Preliminary Assessment

Cited by 18 publications

References 38 publications

Evaluating Functional Diversity: Missing Trait Data and the Importance of Species Abundance Structure and Data Transformation

Evaluating Functional Diversity: Missing Trait Data and the Importance of Species Abundance Structure and Data Transformation

Effect of forest fragmentation on bird species richness in Papua New Guinea

Connectivity with primary forest determines the value of secondary tropical forests for bird conservation

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