Introduction
Forest cover degradation is a highly urgent environmental issue, contributing to the loss of biodiversity and the impacts of global climate change. Forests not only function as carbon sinks but also as important habitats for various species, including birds, which play a vital role in the ecosystem (Brockerhoff, et al., 2017). As a birdwatcher, I believe that bird species can serve as key indicators of the health of a forest ecosystem. When certain bird species begin to disappear or experience a decline in population, it often reflects deteriorating environmental conditions, such as deforestation and habitat fragmentation.
 |
| Bird watching in damaged forest areas |
The presence and diversity of bird species in an area can provide valuable insights into the integrity of the ecosystem. Research shows that birds that depend on dense vegetation cover tend to be more sensitive to habitat changes compared to species that are more adaptable (Buchanan, et al., 2016). Therefore, observing changes in bird communities not only provides an overview of ecosystem health but also offers important data for forest management and conservation. As the pressure on natural habitats increases due to urbanization and agricultural activities, it is crucial for us to understand how bird species can serve as effective indicators in detecting forest cover degradation.
The purpose of this article is to explore how bird species can serve as indicators of forest cover degradation. In this context, I will discuss the characteristics of bird species that are sensitive to habitat changes, provide examples of species that show population declines as a sign of degradation, and explain the observation methods that can be used to identify changes in bird species. Thus, it is hoped that this writing can provide a new perspective for researchers, conservationists, and decision-makers in the efforts to preserve forests.
Basic Concepts
Healthy forest cover plays an important role in maintaining the stability of the global ecosystem, such as providing habitat for flora and fauna species, as well as supporting the carbon and water cycles (Acosta-Muñoz, et al., a2024). Forest cover degradation occurs when forests lose biodiversity, ecosystem functions, and the ability to provide environmental services due to pressures such as deforestation, habitat fragmentation, or other human activities (Dalagnol, et al., 2023). In this context, the decline in forest quality is often not directly detected. However, changes in bird populations and behavior can serve as early indicators of degradation, which can be measured and analyzed more easily than physical landscape changes (Bhowmick, 2021).
Bird diversity is closely related to ecosystem conditions, especially in complex tropical forests. Birds are often considered bioindicators because they occupy various ecological niches and have a high sensitivity to habitat changes (Lu et al., 2024). For example, insectivorous birds that depend on the understory vegetation of forests are often the first species to decline when the forest begins to degrade due to illegal logging or land conversion (Betts, 2022). On the other hand, more generalist and adaptive bird species, such as seed-eating birds or predatory birds, tend to survive longer in disturbed habitats, indicating the loss of specialist species as a sign of ecosystem degradation (Donald, 2018).
Monitoring bird species allows researchers to identify long-term trends related to forest health, so the diversity of bird species can provide a clear picture of forest cover conditions. (Prowse, 2021). Fruit and nectar-eating birds, for example, are highly dependent on intact vegetation and the diversity of flowering trees (May-Uc, et al., 2020). When forest vegetation is fragmented, these species often disappear or move to better areas, reflecting broader habitat degradation. This change not only impacts the forest ecosystem but also disrupts ecological functions that depend on birds, such as pollination and seed dispersal.
Bird Species as Indicators
Bird species play an important role in forest ecosystems and are often used as biological indicators to detect environmental changes, including forest degradation. One of the reasons birds are very effective as indicators is because they occupy various trophic levels and ecological niches, so changes in bird communities can quickly reflect disturbances in the habitat. Some birds, especially insectivorous birds and frugivorous birds, are very sensitive to habitat changes caused by deforestation, fragmentation, or land conversion into plantations (Mariano-Neto et al., 2023). The decline or loss of these species often serves as an early sign of forest ecosystem degradation.
For example, in the tropical forests of Sumatra, birds such as hornbills and other fruit-eating birds are highly dependent on large trees that provide fruits as their main food source. When forest cover decreases or is disturbed, the population of these birds declines drastically due to the loss of food sources and nesting places (Irawan et al., 2020). The decline in the number of hornbills not only affects the diversity of birds themselves but also impacts the forest regeneration process, considering their role in seed dispersal from large trees. Thus, the extinction of this species indicates that the ecological functions of the forest are also disrupted.
Additionally, insectivore birds that live in the understory of the forest often become one of the first groups of birds to be affected by forest degradation. Birds like the Horsfield's babbler (Malacocincla sepiaria) in Sumatra rely on dense vegetation to hunt insects. When the forest understory is disturbed by human activities, such as illegal logging or land clearing for plantations, these species begin to disappear, becoming a clear sign that their habitat has been degraded (Betts et al., 2022). Observations of the decline in bird populations provide a clear picture of how far the process of forest degradation has progressed, especially in forests that are considered not yet fully damaged.
Bird monitoring as an ecosystem indicator becomes very important in the context of conservation, where bird species can provide long-term data that can be used to guide forest management policies. By observing changes in bird communities over time, we can assess the severity of degradation and identify priority areas for ecosystem restoration (Owen et al., 2022). Therefore, studies that integrate bird species data into forest monitoring are crucial for maintaining the sustainability of increasingly threatened tropical ecosystems.
Case Study
The tropical forests of Sumatra, known as one of the world's biodiversity hotspots, have experienced significant degradation due to illegal logging, land conversion into palm oil plantations, and habitat fragmentation. In the Aceh region, monitoring bird species has provided valuable insights into the impact of forest degradation. Based on my observations as a birdwatcher in Aceh, I see that especially in fragmented lowland areas, bird species that depend on intact forest cover, such as those from the Bucerotidae and Muscicapidae families, show a drastic decline in population in highly fragmented areas. The disappearance of this species coincides with the decline in habitat quality, where the large trees they use for nesting and foraging have been cut down.
Example is the significant decline in the population of Helmeted Hornbills in the lowland forests of Sumatra, besides the high level of hunting, the fragmentation of forests by palm oil plantations has become a major factor. Hornbills, which play a key role in the seed dispersal of large trees, are now rarely seen in areas that have undergone intensive deforestation. The presence of this species is closely related to the integrity of the forest canopy and the availability of large fruit trees, which are their main food source (Fitriansyah et al., 2022). The decline in hornbill populations not only indicates habitat degradation but also shows that natural forest regeneration is threatened because their role in seed dispersal has ceased.
Besides hornbills, insectivorous birds living in the understory of the forest also experience similar impacts. One of them is the Mangrove blue-flycatcher (Cyornis rufigastra), which is highly dependent on dense vegetation and insects as its food source, and has significantly declined in areas that have experienced forest fragmentation. When the forest understory is opened up due to human activities, the vegetation that serves as the habitat for these birds decreases, thereby affecting their ability to survive (Betts et al., 2021). This data confirms that bird species living in various forest strata can serve as indicators of habitat conditions and degradation levels.
The high rate of forest fragmentation will negatively impact bird diversity, especially species that depend on intact forest cover. The presence or absence of this bird species provides insight into the level of ecosystem damage and the importance of habitat restoration. Therefore, integrating bird monitoring into forest conservation and rehabilitation plans is crucial to support efforts to preserve threatened tropical forests.
Conservation and Policy Implications.
Birdwatching as an indicator of forest cover degradation has significant implications for conservation and natural resource management. Birds are a group of fauna that can be relatively easily monitored, with their high diversity and dependence on various types of habitats allowing them to function as "bioindicators" of ecosystem health. As a birdwatcher, I see that utilizing bird species data in forest management policies should be a priority to mitigate further damage to threatened ecosystems. Birds, through their behavior responsive to environmental changes, can help predict ecosystem threats even before forest degradation becomes physically apparent.
In several tropical regions, including Sumatra, observations have shown that the forest bird species most affected by forest fragmentation are those that depend on intact forest strata, such as the canopy and understory. In the context of policy, this data provides direction for conservation priorities, for example, by focusing on the protection of forest areas with high bird diversity and targeting restoration in areas experiencing a decline in key species populations. Birds like hornbills, which play a crucial role in the dispersal of large tree seeds, should be the main focus of ecosystem-based conservation programs because their presence affects forest regeneration. The protection of species like this should be taken into consideration in the establishment of protected areas or ecosystem restoration.
Forest management policies must also integrate a science-based approach supported by long-term data from bird surveys. One approach that can be taken is to develop a citizen science program that involves local communities and birdwatchers to conduct sustainable bird population monitoring. This initiative not only raises public awareness about the importance of forest conservation but also enriches the database used to guide forest management policies. Long-term monitoring is crucial for detecting trends in bird species population changes and for assessing the effectiveness of implemented conservation policies.
Overall, the use of birds as indicators of forest degradation offers a scientific and pragmatic way to assess ecosystem health. Thus, this data must be utilized by policymakers in formulating effective conservation strategies, including the protection of critical habitats, forest restoration, and coordinated long-term monitoring. Collaboration between scientists, the government, and local communities will be essential to ensure the sustainability of the remaining tropical forests, which not only protect birds but also the entire interconnected ecosystems within them.
Challenges in Using Bird Species as Indicators
Although bird species have been recognized as effective bioindicators for monitoring ecosystem conditions, there are several significant challenges in widely applying this approach. As a researcher and birdwatcher, I see that one of the main obstacles is the need for consistent and high-quality long-term data. In many cases, bird population monitoring is often sporadic or limited to certain periods, making it difficult to obtain a comprehensive picture of population dynamics in the long term (Duarte, et al., 2024). Without long-term data covering various seasons and environmental conditions, assessments of forest degradation based on bird populations can be inaccurate.
In addition, climate change adds complexity to the use of birds as indicators of forest degradation. Some bird species have shown adaptation to temperature and weather changes by expanding their habitat range to new areas. This phenomenon can complicate the assessment of the impact of local habitat degradation, where species that are usually sensitive to habitat changes still manage to survive in areas fragmented due to climate shifts (Liu et al., 2024). Therefore, it is difficult to separate the impact of deforestation from the influence of climate change, and further research is needed to understand the interaction between these two factors in the context of bird populations.
Another challenge that needs to be considered is the local variation in bird behavior. Some bird species may be more tolerant of habitat changes compared to other species. For example, common birds from the families Apodidae, Cisticolidae, and Pycnonotidae can survive in habitats that have been significantly fragmented or disturbed, while birds like hornbills or woodpeckers are more vulnerable to habitat loss. This requires meticulousness and in-depth research to determine habitat conditions and make birds an important indicator.
In addition, logistical constraints often pose obstacles in the implementation of bird monitoring programs. Many tropical areas experiencing deforestation are located in remote and inaccessible regions, hindering efforts to conduct regular surveys and monitoring. In my experience, some areas in the Sumatra forest that have suffered severe degradation are difficult to access, both due to challenging terrain and security issues on the ground. This results in a lack of data for critical areas, which ultimately limits our understanding of how bird species respond to forest degradation in various types of ecosystems.
To solve these challenges, collaboration between scientists, conservation organizations, and local governments is essential. Development of more innovative monitoring methods. One of them is the bioacoustic method or the use of remote sensing combined with field data, which can help improve the effectiveness of using birds as indicators. With a more integrated and innovative approach, we can overcome these obstacles and harness the full potential of birds as strong bioindicators in forest conservation.
Recommendations for the Use of Bird Species as Indicators in the Future
The use of bird species as indicators of forest cover degradation requires a more integrated approach in the future to maximize their benefits in conservation. One of the main recommendations is the importance of building a wider and more sustainable bird monitoring network. By expanding the geographical coverage of bird monitoring and involving more stakeholders, such as local communities, scientists, and the government, we can gather more representative data on changes in bird populations across various types of forests, from lowlands to mountains. This data is important not only for assessing the current condition of the habitat but also for predicting the long-term impacts of deforestation and climate change.
In addition, new technologies such as audiomuth, camera traps, and drones have opened up greater opportunities for monitoring birds in remote locations that were previously difficult to access. Combining this technology with field observations can provide richer and more comprehensive data on the dynamics of bird species in areas experiencing forest degradation. For example, monitoring using a bioacoustic approach on birds has proven effective in detecting the presence of species that are rarely seen in the field, such as nocturnal birds or species that are more hidden in the forest canopy (Joel, et al., 2024). By using this technology, we can overcome some of the challenges of traditional monitoring that rely on the presence of observers in the field.
The enhancement of cross-disciplinary collaboration is also very much needed in future efforts. Bird scientists need to work more closely with forest ecologists, conservation planners, and policymakers to translate findings from bird monitoring into concrete actions for forest protection. Bird monitoring data is often not fully utilized by policymakers due to a lack of communication between researchers and stakeholders. By building stronger communication channels and facilitating better data exchange between research and policy, we can ensure that bird species conservation aligns with the overall protection of ecosystems.
In addition, it is important to strengthen community-based approaches through citizen science programs, where local communities are involved in bird monitoring. Through the program, it has shown great potential in collecting large-scale data and raising conservation awareness among the local community. This initiative can help monitor bird species more intensively in forest areas experiencing degradation pressure, while also providing economic incentives for the community through birdwatching-based ecotourism. This approach not only increases the volume and quality of the data collected but also promotes the long-term sustainability of forest conservation through local engagement.
Reference
Acosta-Muñoz, C., Navarro-Cerrillo, R.M., Bonet-García, F.J., Ruiz-Gómez, F.J., González-Moreno, P. 2024. Evolution and Paradigm Shift in Forest Health Research: A Review on of Global Trends and Knowledge Gaps. Forests, 15(8), 1279. DOI: 10.1101/2024.06.03.597256.
Betts, M.G., Yang, Z., Hadley, A. S., Smith, A. C. 2022. Forest degradation drives widespread avian habitat and population declines. Nature Ecology & Evolution. 6:709–719. doi: 10.1038/s41559-022-01737.
Bhowmick, S.R. 2021. Biodiversity Assessement of Bird Species as Bioindicators and Impact of Air Pollution on The Ecological. International Journal of Pure and Applied Zoology. 9(2):18-25.
Brockerhoff, E. G., Barbaro, L., Castagneyrol, B., Forrester, D. I., Gardiner, B., et al.. 2017. Forest biodiversity, ecosystem functioning and the provision of ecosystem services. Biodiversity and Conservation. 26 (13), pp.3005-3035. ⟨10.1007/s10531-017-1453-2⟩. ⟨hal-02625784⟩.
Buchanan M.L., Askins R.A., Jones C.C. 2016. Response of Bird Populations To Long-Term Changes In Local Vegetation and Regional Forest Cover. The Wilson Journal of Ornithology 128(4):704-718. DOI: 10.1676/15-108.1.
Dalagnol, R., Wagner, F.H., Galvão, L.S., Braga, D., Osborn, F.M. 2023. et al.. Mapping tropical forest degradation with deep learning and Planet NICFI data. Remote Sensing of Environment, 298, ⟨10.1016/j.rse.2023.113798⟩. ⟨hal-04229541⟩.
Donald, PF., Arendarczyk, B., Spooner, F., Buchanan, G. M. 2018. Loss of forest intactness elevates global extinction risk in birds. Animal Conservation. 22(4). DOI: 10.1111/acv.12469.
Duarte, A., Weldy, M. J., Lesmeister, D. B., Ruff, Z. J., Jenkins, J. M. A., Valente, J. J., and Betts, M. G.. 2024. Passive acoustic monitoring and convolutional neural networks facilitate high-resolution and broadscale monitoring of a threatened species. Ecological Indicators. 162:112016. DOI: 10.1016/j.ecolind.2024.112016.
Fitriansyah, R. A., Setiawan, A., Rustiati E. L., Utoyo, L., Sibarani, M.C.. 2022. Spatial distribution and temporal patterns of food tree availability of hornbills (Bucerotidae) at Way Canguk Research Station, Bukit Barisan Selatan National Park, Indonesia. Biodiversitas Journal of Biological Diversity. 23(4). DOI: 10.13057/biodiv/d230433.
Irawan, D., Nurcahyani, N., ., P., Kanedi, M., & Utoyo, L. (2022). Growth of Hornbill Feed Seeds at Way Canguk Research Station, Bukit Barisan Selatan National Park. Jurnal Ilmiah Biologi Eksperimen Dan Keanekaragaman Hayati (J-BEKH), 9(1), 12–23. https://doi.org/10.23960/jbekh.v9i1.207.
Joel, Y. H., Iniunam, A., Dami, D. F., Ottosson, U., and Chaskda, A. A.. 2024. A comparison of the sampling effectiveness of acoustic recorder, camera trap and point count methods in sampling nocturnal birds in Afrotropical landscapes. Ecology and Evolution. 14(5). DOI: 10.1002/ece3.11389.
Liu, J., Tingley, M. W., Wu, Q., Ren, P., Jin, T., Ding, P., Si, X.. 2024. Habitat fragmentation mediates the mechanisms underlying long-term climate-driven thermophilization in birds. Biorxiv. DOI: 10.1101/2024.04.15.589628.
Lu, X., Jia, Y., Wang, Y. 2024. The effect of landscape composition, complexity, and heterogeneity on bird richness: a systematic review and meta-analysis on a global scale. Landscape Ecology. 39(8). DOI: 10.1007/s10980-024-01933-w.
Mariano-Neto, E., Santos, R. A. S. 2023. Changes in the functional diversity of birds due to habitat loss in the Brazil Atlantic Forest. Frontiers in Forests and Global Change, vol. 6, id. 1041268. DOI: 10.3389/ffgc.2023.1041268.
May-Uc, Y., Nell, C.S., Parra-Tabla, V., Navarro, J., Abdala-Roberts, L. 2020. Tree diversity effects through a temporal lens: Implications for the abundance, diversity and stability of foraging birds. Journal of Animal Ecology 89(8). DOI: 10.1111/1365-2656.13245.
Owen, K. C., Melin, A. D., Campos, F. A., Fedigan, L. M., Gillespie, T. W., and Mennill, D. J.. 2020. Bioacoustic analyses reveal that bird communities recover with forest succession in tropical dry forests. Avian Conservation and Ecology, 15 (1), 1-20. DOI: 10.5751/ACE-01615-150125.
Prowse, T. A. A., O'Connor, P. J., Collard, S. J., Peters, K. J., and Possingham, H. P. 2021. Optimising monitoring for trend detection after 16 years of woodland-bird surveys. Journal of Applied Ecology 58 (5) 1090-1100. https://doi.org/10.1111/1365-2664.13860
.jpeg)
.jpeg)
0 Comments