Biodiversity Data Journal : Data Paper (Biosciences)
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Data Paper (Biosciences)
Avian communities of betel nut agroforestry and secondary forest in Taiwan
expand article infoJo-Szu Tsai‡, Chia-Hao Chang‡, Ping Huang§, Jerome Chie-Jen Ko§, Fu-Hsiung Hsu‡
‡ National Chiayi University, Chiayi City, Taiwan
§ Taiwan Biodiversity Research Institute, Chichi township, Taiwan
Corresponding author: Jo-Szu Tsai (ross.tsai@gmail.com)
Academic editor: Krizler Tanalgo
Received: 25 Jan 2025 | Accepted: 12 Apr 2025 | Published: 05 May 2025
© 2025 Jo-Szu Tsai, Chia-Hao Chang, Ping Huang, Jerome Chie-Jen Ko, Fu-Hsiung Hsu
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation: Tsai J-S, Chang C-H, Huang P, Ko JC-J, Hsu F-H (2025) Avian communities of betel nut agroforestry and secondary forest in Taiwan. Biodiversity Data Journal 13: e147871. https://doi.org/10.3897/BDJ.13.e147871
 Open Access

Abstract

Background

Betel nut agroforestry had quickly grown to occupy more than 1% of the land in Taiwan, often taking the place of secondary forests. While agroforestry systems can help mitigate biodiversity loss by preserving habitat structure and providing essential ecological services, the ecological role of betel nut plantations — particularly their impact on avian communities — remains largely understudied. Birds, as sensitive indicators of environmental change, offer valuable insights into habitat quality and biodiversity health. To address this knowledge gap, we conducted standardised point count surveys to collect data on bird species composition and abundance.

New information

This was the first avian dataset focused on betel nut agroforestry, providing detailed bird occurrence data for betel nut plantations and secondary forests. The dataset is particularly useful for understanding how agriculture alters ecological services in human-modified landscapes. Data were collected during the breeding seasons (March to May) of 2015 and 2016 across 80 sites in four counties of central Taiwan. Each site included five sampling points, with avian community data recorded twice per season at each point. This publicly available dataset on GBIF offers valuable insights into avian biodiversity and habitat use in agricultural ecosystems.

Keywords

avian communities, agroforestry, betel nut, secondary forest, subtropical Asia

Introduction

The conversion of natural habitats to farmlands drives biodiversity loss globally (Altieri 1999, Dudley and Alexander 2017, Williams et al. 2020), with intensive agriculture further threatening species diversity (Hazell and Wood 2008, Raven and Wagner 2021). Agroforestry systems, such as coffee, oil palm and rubber, can mitigate these impacts by creating refuge habitats, but their biodiversity value depends on management practices (Dietsch et al. 2007, Jose 2009, Karp et al. 2013). As a relatively unexamined system, betel nut agroforestry presents a valuable chance to study biodiversity within agricultural landscapes. Although it maintains tree cover and sustains livelihoods, its ecological advantages and challenges differ. Betel nut agroforestry predominantly exists in the tropical and subtropical zones of South and Southeast Asia, where it plays a vital role in both cultural traditions and economic functions (Pratt 2014, Singh et al. 2020). Despite the association of health concerns and social challenges, betel nut agroforestry plays a crucial economic and cultural role in these regions (Tham et al. 2017, Luong et al. 2024).

In Taiwan, betel nut plantations are a vital type of agroforestry, particularly in the hillside areas of central and southern Taiwan below 1200 m above sea level. The planting area has been increasing forty-fold since the 1960s and peaked in the 1990s due to its high economic value (Liu 2010), exceeding one percent of the total land area in Taiwan. The expansion of betel nut replaced vast areas of secondary forests, raising concerns about their potential impacts on ecological services, particularly in mountainous regions. Betel nut agroforestry systems retain tree cover, but often cause higher runoff and erosion than secondary forests, posing soil and water conservation challenges (Lu et al. 1999, Cheng et al. 2008). Despite its widespread economic significance, the effect of betel nut plantation expansion on biodiversity remains underexplored. Birds are sensitive to environmental change and habitat diversity and are regarded as significant indicators for biodiversity health (Fraixedas et al. 2020). Studying how these mobile organisms engage with betel nut agroforestry will clarify the implications of these plantations on avian community composition and dynamics, especially when compared to secondary forests, which are considered vital biodiversity reservoirs in human-altered landscapes.

The primary aim of this dataset was to address the knowledge gap concerning the ecological impact of betel nut agroforestry on avian biodiversity in central Taiwan. Specifically, we collected the composition and diversity of bird communities in betel nut agroforestry systems with those in adjacent secondary forests. With this dataset, we aimed to provide insights into the potential role of betel nut plantations in supporting avian populations. Such information is essential for guiding sustainable management practices and balancing economic and ecological interests in the region.

Project description

Title: 

Avian communities of betel nut agroforestry and secondary forest in Taiwan

Study area description: 

The study area is in the subtropical climate. The annual average temperature is 23℃ and the annual rainfall is 1774.3 mm. The rainy season is from June to August caused by the southwest monsoon.

Sampling methods

Sampling description: 

We conducted five point count surveys in 40 betel nut and 40 secondary forest plots in March to May 2015 and 2016 in central Taiwan (Fig. 1). Following a standard point count procedure (Buckland et al. 2005), we spent 6 minutes at each point to record the number of different bird species we saw and heard and the distance of each bird determined by Laser range finder (Nikon laser 1000AS).

Figure 1.  

Locations of 40 betel nut agroforestry and 40 secondary forest plots in central Taiwan.

We identified homogeneous patches of secondary forest and betel nut plantation below 1200 m above sea level using Google Earth software (Google Inc.) that are larger than 13.6 ha. We then selected 40 secondary forest and 40 betel nut plantation plots that are at least 4 km apart from the plot centre. Within each plot, we established five sampling points along the designated road system, with each point at least 200 m apart to prevent double-counting. Bird sampling was conducted within 4 hours after sunrise on a clear day (without rain and strong wind). Each sampling point was surveyed twice in the breeding season (March to May). For each bird record, the following information was collected: bird species (the smallest taxonomic unit: species), number of individuals (number), horizontal distance to the observer and flock formation with more than five individuals were recorded. In 2015, the horizontal distance was recorded using four categories (0-25 m, 25-100 m, >100 m and flyovers), following the standardised method used in the Taiwan Breeding Bird Survey (Ko et al. 2017). However, we recognised that these broad categories might be too coarse for accurately estimating detection probabilities in future analyses. Therefore, starting in 2016, distance estimation was refined to 10-m bands (in addition to a flyover category) to enhance precision and allow greater flexibility in future data applications. For each sampling point record, investigation date (year, month and day), starting time, observer and weather condition (clear, cloudy, overcast, fog, drizzle or showers) were recorded. Wind conditions during the survey were also recorded and categorised into four levels, based on the Beaufort scale: (1) Calm to Light Air (Beaufort 0–1), (2) Light to Gentle Breeze (2–3), (3) Moderate to Fresh Breeze (4–5) and (4) Strong Breeze and Above (≥ 6). To ensure data collection consistency, the investigation was conducted by four experienced investigators, all of whom had prior field experience in forest bird surveys. At the beginning of the study, all investigators underwent briefings in the field to align and standardise procedures for species identification and distance estimation. A laser rangefinder was used to obtain actual distance measurements, standardising the investigators’ reference points. The taxonomic system follows the Checklist of Birds of Taiwan, maintained by the Bird Record Committee of the Taiwan Wild Bird Federation (Ding et al. 2023).

Geographic coverage

Description: 

The records in this dataset are collected from the central region of Taiwan island, including Nantou, Yunlin, Chiayi and Tainan Counties.

Coordinates: 

23.101 and 24.047 Latitude; 120.355 and 120.914 Longitude.

Taxonomic coverage

Description: 

This dataset focused on the avian communities in Taiwan. We recorded 85 species distributed in 11 orders and 39 families. Detailed information of bird order, family and occurrences were described in Table 1.

Table 1.
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Taxonomic composition of bird species observed in betel nut agroforestry and secondary forest in Taiwan.

Rank Order Family Scientific name Occurrences in betel nut agroforestry Occurrences in secondary forest
1 Accipitriformes Accipitridae Accipiter trivirgatus (Temminck, 1824) 17 11
2 Accipitriformes Accipitridae Accipiter virgatus (Temminck, 1822) 2 2
3 Accipitriformes Accipitridae Accipiter soloensis (Horsfield, 1821) 1 1
4 Accipitriformes Accipitridae Butastur indicus (Gmelin, 1788) 0 3
5 Accipitriformes Accipitridae Ictinaetus malayensis (Temminck, 1822) 1 0
6 Accipitriformes Accipitridae Pernis ptilorhynchus (Temminck, 1821) 2 2
7 Accipitriformes Accipitridae Spilornis cheela (Latham, 1790) 63 84
8 Accipitriformes Pandionidae Pandion haliaetus (Linnaeus, 1758) 0 1
9 Apodiformes Apodidae Apus nipalensis (Hodgson, 1837) 20 25
10 Columbiformes Columbidae Chalcophaps indica (Linnaeus, 1758) 33 46
11 Columbiformes Columbidae Columba pulchricollis (Blyth, 1846) 0 3
12 Columbiformes Columbidae Columba livia (J.F.Gmelin, 1789) 0 1
13 Columbiformes Columbidae Spilopelia chinensis (Scopoli, 1786) 82 48
14 Columbiformes Columbidae Streptopelia orientalis (Latham, 1790) 23 20
15 Columbiformes Columbidae Streptopelia tranquebarica (Hermann, 1804) 9 1
16 Columbiformes Columbidae Treron sieboldii (Temminck, 1835) 14 43
17 Coraciiformes Alcedinidae Alcedo atthis (Linnaeus, 1758) 1 1
18 Cuculiformes Cuculidae Cuculus optatus (Gould, 1845) 114 54
19 Cuculiformes Cuculidae Cuculus sparverioides (Vigors, 1832) 0 3
20 Galliformes Phasianidae Arborophila crudigularis (Swinhoe, 1864) 17 31
21 Galliformes Phasianidae Bambusicola sonorivox (Gould, 1863) 141 138
22 Galliformes Phasianidae Lophura swinhoii (Gould, 1863) 0 3
23 Gruiformes Rallidae Rallina eurizonoides (Lafresnaye, 1845) 1 0
24 Passeriformes Aegithalidae Aegithalos concinnus (Gould, 1855) 1 1
25 Passeriformes Campephagidae Pericrocotus solaris (Blyth, 1846) 6 48
26 Passeriformes Cettiidae Abroscopus albogularis (Moore, 1854) 87 143
27 Passeriformes Cisticolidae Prinia striata (Swinhoe, 1859) 12 2
28 Passeriformes Cisticolidae Prinia flaviventris (Delessert, 1840) 3 2
29 Passeriformes Cisticolidae Prinia inornata (Sykes, 1832) 4 0
30 Passeriformes Corvidae Corvus macrorhynchos (Wagler, 1827) 4 9
31 Passeriformes Corvidae Dendrocitta formosae (Swinhoe, 1863) 94 158
32 Passeriformes Dicaeidae Dicaeum minullum (Swinhoe, 1870) 6 44
33 Passeriformes Dicaeidae Dicaeum ignipectus (Blyth, 1843) 3 3
34 Passeriformes Dicruridae Dicrurus aeneus (Vieillot, 1817) 47 104
35 Passeriformes Dicruridae Dicrurus macrocercus (Vieillot, 1817) 13 4
36 Passeriformes Estrildidae Lonchura striata (Linnaeus, 1766) 25 12
37 Passeriformes Estrildidae Lonchura punctulata (Linnaeus, 1758) 4 1
38 Passeriformes Fringillidae Pyrrhula nipalensis (Hodgson, 1836) 0 1
39 Passeriformes Hirundinidae Cecropis striolata (Schlegel, 1844) 18 8
40 Passeriformes Hirundinidae Delichon dasypus (Bonaparte, 1850) 0 2
41 Passeriformes Hirundinidae Hirundo tahitica (Gmelin, 1789) 32 30
42 Passeriformes Hirundinidae Hirundo rustica (Linnaeus, 1758) 4 2
43 Passeriformes Laniidae Lanius cristatus (Linnaeus, 1758) 0 1
44 Passeriformes Leiothrichidae Garrulax canorus (Linnaeus, 1758) 4 5
45 Passeriformes Leiothrichidae Garrulax poecilorhynchus (Gould, 1863) 1 4
46 Passeriformes Leiothrichidae Heterophasia auricularis (Swinhoe, 1864) 17 78
47 Passeriformes Leiothrichidae Liocichla steerii (Swinhoe, 1877) 29 85
48 Passeriformes Leiothrichidae Trochalopteron morrisonianum (Ogilvie-Grant, 1906) 0 1
49 Passeriformes Monarchidae Hypothymis azurea (Boddaert, 1783) 225 277
50 Passeriformes Motacillidae Anthus hodgsoni Richmond, 1907 0 1
51 Passeriformes Motacillidae Motacilla alba (Linnaeus, 1758) 3 0
52 Passeriformes Motacillidae Motacilla cinerea (Tunstall, 1771) 1 1
53 Passeriformes Muscicapidae Copsychus malabaricus (Scopoli, 1786) 6 19
54 Passeriformes Muscicapidae Myiomela leucura (Hodgson, 1845) 24 56
55 Passeriformes Muscicapidae Myophonus insularis (Gould, 1863) 6 19
56 Passeriformes Muscicapidae Niltava vivida (Swinhoe, 1864) 1 1
57 Passeriformes Oriolidae Oriolus traillii (Vigors, 1832) 6 23
58 Passeriformes Paridae Parus monticolus (Vigors, 1831) 6 8
59 Passeriformes Passeridae Passer montanus (Linnaeus, 1758) 36 0
60 Passeriformes Pellorneidae Alcippe morrisonia (Swinhoe, 1863) 397 472
61 Passeriformes Pellorneidae Alcippe brunnea (Gould, 1863) 296 432
62 Passeriformes Phylloscopidae Phylloscopus inornatus (Blyth, 1842) 0 6
63 Passeriformes Phylloscopidae Phylloscopus borealis (J.H.Blasius, 1858) 0 1
64 Passeriformes Pittidae Pitta nympha Temminck & Schlegel, 1850 0 2
65 Passeriformes Pycnonotidae Hypsipetes leucocephalus (Gmelin, 1789) 496 388
66 Passeriformes Pycnonotidae Pycnonotus sinensis (Gmelin, 1789) 456 217
67 Passeriformes Pycnonotidae Spizixos semitorques (Swinhoe, 1861) 29 41
68 Passeriformes Sturnidae Acridotheres javanicus (Cabanis, 1851) 26 0
69 Passeriformes Sturnidae Acridotheres cristatellus (Linnaeus, 1758) 2 0
70 Passeriformes Timaliidae Pomatorhinus musicus (Swinhoe, 1859) 285 446
71 Passeriformes Timaliidae Pomatorhinus erythrocnemis (Gould, 1863) 127 199
72 Passeriformes Timaliidae Stachyridopsis ruficeps (Blyth, 1847) 461 423
73 Passeriformes Turdidae Turdus chrysolaus (Temminck, 1832) 2 6
74 Passeriformes Turdidae Turdus pallidus (Gmelin, 1789) 1 1
75 Passeriformes Vireonidae Erpornis zantholeuca (Blyth, 1844) 22 52
76 Passeriformes Zosteropidae Yuhina brunneiceps (Ogilvie-Grant, 1906) 2 9
77 Passeriformes Zosteropidae Zosterops simplex (Swinhoe, 1861) 248 65
78 Pelecaniformes Ardeidae Bubulcus ibis (Linnaeus, 1758) 7 8
79 Pelecaniformes Ardeidae Egretta garzetta (Linnaeus, 1766) 6 7
80 Pelecaniformes Ardeidae Gorsachius melanolophus (Raffles, 1822) 3 3
81 Pelecaniformes Ardeidae Nycticorax nycticorax (Linnaeus, 1758) 0 2
82 Pelecaniformes Ardeidae Ardea alba (Linnaeus, 1758) 1 0
83 Piciformes Megalaimidae Psilopogon nuchalis (Gould, 1863) 538 567
84 Piciformes Picidae Yungipicus canicapillus (Blyth, 1845) 37 46
85 Strigiformes Strigidae Glaucidium brodiei (Burton, 1836) 1 9

Temporal coverage

Notes: 

2015-03-01 through 2015-05-31, 2016-03-01 through 2016-05-31.

Usage licence

Usage licence: 
Creative Commons Public Domain Waiver (CC-Zero)
IP rights notes: 
This work is licensed under a Creative Commons Attribution (CC-BY 4.0) License.

Data resources

Data package title: 
Avian communities of betel nut plantation and secondary forest in Taiwan
Resource link: 
https://doi.org/10.15468/wkdnqx
Alternative identifiers: 
6ef6360c-c904-4eab-87fe-7bd234cb5c42
Number of data sets: 
1
Data set name: 
Avian communities of betel nut plantation and secondary forest in Taiwan.
Data format: 
Darwin Core
Description: 

This was a project focusing on understanding avian communities in the betel nut plantation and the secondary forest in Taiwan. We collected the data in the breeding season (March to May) in 2015 and 2016 in a total of 80 sites in four counties in central Taiwan (Tsai et al. (2025)). There were five sampling points in each site and we collected avian community data at each point twice in each season.

Column label Column description
eventID The identifier for each sampling event.
parentEventID The identifier for the sampling year (and locationID) for the nested sampling events, each with its own evnetID.
eventDate The date during which a sampling event occurred.
eventTime The time during which a sampling event occurred.
samplingProtocol Protocol used in sampling events.
sampleSizeValue The area where a sampling event occurred.
sampleSizeUnit The unit of the area where a sampling event occurred.
samplingEffort The amount of time spent during a sampling event.
locationID The identifier for each sampling site.
country The name of the country where the sampling events occurred.
countryCode The standard code for the country where the sampling events occurred.
decimalLatitude The geographic latitude in decimal degrees of the centre of a sampling site.
decimalLongitude The spatial reference system on which the geographic coordinates of sampling sites were based.
coordinateUncertaintyInMetres The horizontal distance (in metres) from the given sampling site coordinates describing the smallest circle containing the whole of the sampling site.
Type The nature of the record resource.
basisOfRecord The specific nature of the data record.
occurrenceID The identifier for each occurrence record.
recordedBy The names of people responsible for each occurrence record.
individualCount The number of individuals of the species observed during the 6-min observation time.
occurrenceRemarks Comments or notes about the given occurrence record.
scientificName The scientific name for the species presented in the occurrence record.
kingdom The scientific name of the kingdom in which the species is classified.
phylum The scientific name of the phylum in which the species is classified.
class The scientific name of the class in which the species is classified.
Order The scientific name of the order in which the species is classified.
family The scientific name of the family in which the species is classified.
genus The scientific name of the genus in which the species is classified.
taxonRank The taxonomic rank of the most specific name of the species.
vernacularName Chinese common name for the species.
measurementID The identifier for each measurement of fact took during sampling.
measurementType The nature of each measurement.
measurementValue The value of each measurement.
measurementDeterminedBy The names of people who took the measurements.
measurementDeterminedDate The date on which the measurement was made.
measurementMethod The method or protocol used to determine the measurement.
geodeticDatum The spatial reference system on which the geographic coordinates of sampling sites were based.

Acknowledgements

We thank Wei-Jai Wen and Shun-Yun Chang for conducting part of the survey.

Author contributions

Jo-Szu Tsai: Conceptualisation, Investigation, Methodology, Project administration, Supervision, Writing - original draft, Writing - review and editing. Chia-Hao Chang: Data curation, Investigation, Visualisation, Writing - original draft. Ping Huang: Data curation, Validation, Writing - review and editing. Jerome Chie-Jen Ko: Funding acquisition, Supervision, Validation, Writing - review and editing. Fu-Hsiung Hsu: Conceptualisation, Methodology, Resources, Supervision, Writing - review and editing.

References

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