Global Biodiversity Conservation Research Articles

Mapping drivers of land conversion among smallholders: A global systems perspective

CONTEXTAgriculture-driven land conversion poses a significant threat to global biodiversity conservation. Balancing agricultural expansion with conservation is a critical challenge for governments and development partners. Sustainability-oriented agriculture programs such as conservation agriculture and land intensification aim to reduce land conversion and deforestation; however, evidence of their effectiveness remains complex and elusive, especially regarding the role of smallholders. OBJECTIVEThis study addresses this knowledge gap by systematically mapping the drivers of smallholder land conversion and their interconnections across three focal biodiverse contexts including sub-Saharan Africa, Latin America, and Southeast Asia as well as from a global scale. METHODSUsing literature that focuses on the nexus of smallholder farmers and agricultural intensification, this study systematically identified the potential of distinct factors and dynamic processes to serve as system leverage points toward improved outcomes for biodiversity, food security, and smallholder livelihoods, using a combination of structural factor analysis, centrality analysis, and feedback loop analysis. RESULTS AND CONCLUSIONSThe results highlight the importance of strengthening land tenure systems, providing technical support to farmers, improving market access, and prioritizing smallholder livelihoods in mitigating land conversion. SIGNIFICANCEContextual differences emphasize the need for context-specific interventions and further research to explore factors driving land conversion more deeply within specific contextual boundaries. Future studies should map proposed policy interventions onto local systems driving land conversion and incorporate the diverse perspectives of local stakeholders to guide effective and sustainable agriculture interventions.

The Ne/N ratio in applied conservation.

Recent developments within the IUCN and the Convention on Biological Diversity have affirmed the increasingly key role that effective population size (N e) and the effective size: census size ratio (N e/N) play in applied conservation and management of global biodiversity. This paper reviews and synthesizes information regarding the definition of N e and demographic and genetic methods for estimating effective size, census size, and their ratio. Emphasis is on single-generation estimates of contemporary N e/N, which are the most informative for practical applications. It is crucial to clearly define which individuals are included in the census size (N). Defining N as the number of adults alive at a given time facilitates comparisons across species. For a wide range of applications and experimental designs, inbreeding N e is simpler to calculate and interpret than variance N e. Effects of skewed sex ratio are generally modest, so most reductions to N e/N arise from overdispersed (greater-than-Poisson) variance in offspring number (). Even when fecundity changes with age, overdispersed within-age variance generally contributes most to overall , and both random and deterministic (mediated by selection) factors can be important. Most species are age-structured, so it is important to distinguish between effective size per generation (N e) and the effective number of breeders in one season or year (N b). Both N e and N b are important for applied conservation and management. For iteroparous species, a key metric is variance in lifetime reproductive success (), which can be affected by a variety of additional factors, including variation in longevity, skip or intermittent breeding, and persistent individual differences in reproductive success. Additional factors that can be important for some species are also discussed, including mating systems, population structure, sex reversal, reproductive compensation, captive propagation, and delayed maturity.

Opening the black box: explainable deep-learning classification of wood microscopic image of endangered tree species

BackgroundTraditional method of wood species identification involves the use of hand lens by wood anatomists, which is a time-consuming method that usually identifies only at the genetic level. Computer vision method can achieve "species" level identification but cannot provide an explanation on what features are used for the identification. Thus, in this study, we used computer vision methods coupled with deep learning to reveal interspecific differences between closely related tree species.ResultA total of 850 images were collected from the cross and tangential sections of 15 wood species. These images were used to construct a deep-learning model to discriminate wood species, and a classification accuracy of 99.3% was obtained. The key features between species in machine identification were targeted by feature visualization methods, mainly the axial parenchyma arrangements and vessel in cross section and the wood ray in tangential section. Moreover, the degree of importance of the vessels of different tree species in the cross-section images was determined by the manual feature labeling method. The results showed that vessels play an important role in the identification of Dalbergia, Pterocarpus, Swartzia, Carapa, and Cedrela, but exhibited limited resolutions on discriminating Swietenia species.ConclusionThe research results provide a computer-assisted tool for identifying endangered tree species in laboratory scenarios, which can be used to combat illegal logging and related trade and contribute to the implementation of CITES convention and the conservation of global biodiversity.

The International Union for Conservation of Nature Red List does not account for intraspecific diversity

Abstract The International Union for Conservation of Nature (IUCN) Red List identifies threatened and endangered species and is a key instrument in global biodiversity conservation efforts. Our understanding of the structure and value of genetic biodiversity below the species level is rapidly increasing. Nonetheless, the IUCN assessment criteria overlook genetic variation within species. Here, we address this blind spot and discuss the principles of species conservation status classification relative to intraspecific biodiversity. We focus on coastal species, which thrive in heterogeneous environments known to drive genetic differentiation. The focal example species, Atlantic cod and sugar kelp, have contrasting life histories, are ecologically and economically important constituents of the coastal ecosystem, and are currently not classified as threatened in Norway and Canada. We expose important variation in population structure, the presence of ecotypes and genetic-environment covariation, as well as loss of ecotypes that threatens the conservation of these species. Because the genetic makeup of species directly influences their resilience, omitting this information from conservation status assessments can result in loss of adaptive capacity to future stressors, such as climate change. Consequently, recognizing and preserving intraspecific variation emerges as vital for species’ abilities to adapt to and survive in future ocean conditions.

Comparative assessment of eDNA metabarcoding and longline deployments for elasmobranch surveying across a large tropical marine park network

Abstract Medium‐ to large‐scale marine protected areas (MPAs) are playing an increasingly important role in global marine biodiversity conservation. A key question is “how do we collect relevant data on biodiversity and population trends to inform their design and measure success?” This question is particularly relevant for marine taxa that are difficult to survey, such as sharks and rays, and where populations may occur over vast areas. Environmental DNA (eDNA) metabarcoding has proven to be an effective sampling method and may provide a solution to these challenges; however, it remains unclear how its sampling effectiveness compares with traditionally used methods for elasmobranch surveying. Here, we directly compared the efficacy of eDNA metabarcoding and demersal longline deployments to survey elasmobranchs across 31 sites over a 55,000 km2 area of the Kimberley and Roebuck Australian Marine Parks in Australia's North‐west Marine Parks Network. In total, we documented 49 unique elasmobranch taxa, 36 of which were detected by eDNA and 32 (from a total of 815 captured sharks) by longline. A combined approach yielded over 34% more elasmobranch taxa than either method alone. Site community compositions varied between the two survey methods; notably eDNA was able to detect species from outside of the immediate sampling area, although this was still consistent with a detection radius of a few kilometres, highlighting a particular use in rugose reef habitats where it is difficult to deploy longlines. In investigating the quantitative use of eDNA data, we report that eDNA metabarcoding read abundance (count) data was poorly correlated with longline aggregate catch (count and biomass) data across raw, relative and rank abundance measures. However, we found that in multivariate analyses, both binary (presence–absence) and abundance (after square‐root transformation) datasets produced highly similar ordination patterns, largely segregating method (eDNA vs. longline), followed by latitude and depth. Lastly, we identified required levels of eDNA replication and longline deployments to maximize captured elasmobranch diversity. This study sets an integrated, georeferenced baseline and long‐term monitoring approach for the management and conservation of elasmobranch diversity within this unique marine park network.

Proximity to natural forests failed to rescue a declining agroforestry tree species

The conservation of species in human-modified landscapes such as agroforestry systems is central to global conservation and sustainable use of biodiversity. Understanding the dynamics of key species in agroforestry systems is important for predicting the sustainability of these systems. However, the population dynamics of agroforestry tree species are often unknown, and planning for the management of these systems is generally grounded on the untested assumption that the tree component will persist over time. Here, we developed an integral projection model for Vitellaria paradoxa (Sapotaceae), one of the most important tree species in traditional agroforestry systems in West Africa. We collected three years of demographic data from six populations around the Pendjari Biosphere Reserve in Benin to parameterize this model and test the effect of populations’ proximity to natural habitats on the short- and long-term dynamics of V. paradoxa. However, models suggest that V. paradoxa populations are projected to decline at a yearly rate of 10.6% and within the next two decades, this tree will be locally extinct. We found a significant positive effect of proximity to natural forest on the long-term population dynamics, but this failed to save populations from decline. Elasticity analyses show that the best strategy to slow down such a decline includes preserving the largest mature trees. However, traditional management systems that protect shea butter trees in agroforestry systems are now replaced by increasing tree cutting to produce firewood, charcoal and carve out mortars and pestles. The decline of this key agroforestry tree poses a broader threat to long-term sustainability of agroforestry systems.

Maintaining the native gut microbiota of bharal (Pseudois nayaur) is crucial in ex situ conservation.

As wildlife protection continue to strengthen, research on the gut microbiota of wildlife is increasing. Carrying out conservation and research on endangered species in the Qinghai Tibet Plateau plays an important role in global biodiversity conservation. This study utilized 16S rRNA sequencing of fecal samples to investigate the composition, function, and changes of the gut microbiota of bharal in different environments, seasons, and genders. The results showed that Firmicutes and Bacteroidota were the dominant phyla and UCG-005, Bacteroides, UCG-010 were the dominant genera of bharal. In the wild, the abundance of Firmicutes increased which was conducive to the decomposition and utilization of cellulose, hemicellulose, and carbohydrate. Due to the variety of food types and nutrition in different seasons, the composition and function of gut microbiota were obviously different between genders. Compared with zoo, higher alpha diversity, a more complex gut microbiota network structure, and stronger metabolic function were conducive bharal to adapting to the wild environment. In the zoo, captive bharals were fed foods rich in high fat and protein, which increased the abundance of Bacteroidota and reduced the alpha diversity of gut microbiota. A fixed diet unified the gut microbiota between genders of bharal. It is very important to pay attention to the impact of captive environments and maintain the native gut microbiota of wildlife.

Identifying Strategies for Effective Biodiversity Preservation and Species Status of Chilean Amphibians.

Resources are limited in global biodiversity conservation efforts, which emphasizes the significance of setting conservation priorities. Using standardized criteria, we evaluated 58 amphibian species in Chile to determine their conservation priority (CP). Species with insufficient historical data had their values marked as missing. With a median value of p = 1.67, the results demonstrated CP values ranging from p = 0.48 to p = 3.0, classifying species into priority and non-priority groups. Four levels were established for the priority categories: no priority, low priority, medium priority, and high priority. Additionally, the Telmatobiidae and Alsodidae families were identified as two more priority families. Notably, the species with the highest priority were found to be T. halli, T. fronteriensis, T. philippii, T. chusmisensis, A. pehuenche, and Alsodes tumultuosus, where T. philippii and T. fronteriensis have equal priority for conservation at the national level according to the conservation priority analysis. Eight priority families-the Alsodidae, Batrachylidae, Bufonidae, Ceratophryidae, Leptodactylidae, Rhinodermatidae, and Telmatobiidae-were determined, and 14 species-or 24% of the species examined-need further study. Based on the conservation priority analysis, the species T. fronteriensis and T. philippii share the highest priority for conservation at the national level (p = 2.50). With 70% of the amphibians under study being threatened mainly by habitat loss, pollution, and emerging diseases, the creation of conservation categories made the threat assessment process easier. Due to a lack of information on geographic distribution and abundance, quantitatively classifying amphibians in Chile remains difficult. The analysis of conservation priorities and potential extinction threats informs appropriate management strategies.

Configuring the field of global marine biodiversity conservation

IntroductionThe article describes and analyzes the emergence of the field of global marine biodiversity conservation over the past fifteen years. We draw on collaborative research at international meetings, which we position as ‘field’ sites, places where diverse actors come together to negotiate the meaning and terms of global environmental governance and where that work is accessible and visible to researchers.MethodsBased on Collaborative Event Ethnography (CEE), a method developed to facilitate study of large meetings, we mobilize research from seven meetings since 2008 to describe the field of global marine biodiversity conservation, but more importantly to specifying how that field has been configured.ResultsWe identify practices of orchestration, narrative, performance, alliance, social objects, devices, and technologies, formal outcomes, and formal procedures, and their use at three phases of field configuration: building, framing, and bounding.DiscussionThe results: 1) enhance our understanding of the role of international conferences in global environmental governance generally, and for marine biodiversity conservation specifically; 2) demonstrate the relevance of field and field configuration theory; 3) contribute to theory on institutional fields by specifying practices of field configuration.

Effects of Land Cover on the Taxonomic and Functional Diversity of the Bird Communities on an Urban Subtropical Mountain

Mountain ecosystems are crucial for global biodiversity conservation. However, their landscape features are constantly changing owing to urban expansion. Understanding the relationships between biotic communities and landscape features is essential for biodiversity conservation. This study aimed to examine the effect of land cover type on avian communities in Lishui, a mountainous urban area in eastern China. Avian surveys were conducted using 168 line transects in total across different land cover types once per season from December 2019 to January 2021. We assessed the diversity of bird communities by calculating various metrics at both taxonomic and functional levels. Among the land cover types measured, woodland, built-up land, cultivated land, and water bodies significantly influenced bird community diversity and composition. Species richness, species abundance, and functional richness were negatively correlated with the proportion of woodland but were positively correlated with the proportion of non-natural land cover, such as built-up and cultivated land. In contrast, functional evenness was positively correlated with the proportion of woodland and grassland but negatively correlated with the proportion of non-natural land cover. Land cover type also exhibited significant correlations with avian functional characteristics such as diet, foraging strata, and body mass, thereby influencing the overall community structure. Our results indicated that mountainous landscape patterns substantially affect avian communities. Different land cover types possess varying resource endowments that affect the distribution of avian species. Therefore, urban landscape planning in mountainous areas should carefully consider the various functions provided to organisms by different types of land cover to promote biodiversity.

Global multifaceted biodiversity patterns, centers, and conservation needs in angiosperms.

The Convention on Biological Diversity seeks to conserve at least 30% of global land and water areas by 2030, which is a challenge but also an opportunity to better preserve biodiversity, including flowering plants (angiosperms). Herein, we compiled a large database on distributions of over 300,000 angiosperm species and the key functional traits of 67,024 species. Using this database, we constructed biodiversity-environment models to predict global patterns of taxonomic, phylogenetic, and functional diversity in terrestrial angiosperms and provide a comprehensive mapping of the three diversity facets. We further evaluated the current protection status of the biodiversity centers of these diversity facets. Our results showed that geographical patterns of the three facets of plant diversity exhibited substantial spatial mismatches and nonoverlapping conservation priorities. Idiosyncratic centers of functional diversity, particularly of herbaceous species, were primarily distributed in temperate regions and under weaker protection compared with other biodiversity centers of taxonomic and phylogenetic facets. Our global assessment of multifaceted biodiversity patterns and centers highlights the insufficiency and unbalanced conservation among the three diversity facets and the two growth forms (woody vs. herbaceous), thus providing directions for guiding the future conservation of global plant diversity.

Identification and analysis of conservation gap of national nature reserves in China

The global system of nature reserves is facing adjustment and restructuring towards the goal of harmonizing ecological conservation with regional development. We use multiple ecoregion data at both global and national scales as ecological indicators to explore the gap areas of China's nature reserves, which can help to build a global network of nature reserve systems and lay a spatial foundation for global biodiversity conservation. This paper comprehensively resorts to the ideas and modeling approaches involved in gap analysis, conservation prioritization analysis and eco-region planning. After identifying in both global and national scales the potential areas with gaps in national nature reserves in China, it proposes conservation priority areas and optimization strategies. The study finds that in a global extent, the areas with the gaps in China cover a large area and are distributed widely, mostly on the both sides of the Tengchong-Heihe Line. The conservation priority areas are concentrated in mid-subtropical humid areas, plateau subtropical sub-humid areas and semi-arid areas, and plateau temperate humid/sub-humid areas. These areas are usually not sufficiently protected due to their diversified landforms, complex ecosystems and lack of protection measures. The results have verified and identified the areas with gaps in the building of Chinese national nature reserve system. They may make a unique and important contribution to global ecological conservation efforts in terms of protected area system optimization and conservation network building. SynopsisThis paper analyses the conservation gaps in China's national nature reserves and proposes conservation priority areas for optimising the layout of the nature reserve network.

Identifying the impact of global human activities expansion on natural habitats

Human activities expansion globally has exerted tremendous pressure on natural habitats and threatens the conservation of global biodiversity. Studying the impact of human activities expansion on natural habitats globally and in various biomes can provide scientific reference for differentiated approaches to global habitat restoration. However, previous studies still lack identification of the impact of global human activities expansion on natural habitats, especially in different biomes. Here we used the InVEST model to assess the changes in habitat quality globally and across biomes over the past 20 years and analyzed the impact of human activities expansion on them using Spearman correlation coefficients. The results showed an overall global degradation of natural habitats of 0.537% during 2000–2020, while human activities increased by 10.990%. Mangroves were the biomes with the most severe habitat degradation, while deserts and xeric shrublands were the biomes with the most significant habitat restoration. At the global scale, human activities had caused significant and growing negative impact on natural habitats, while in terms of different biomes, human activities may bring about habitat restoration. The findings of this study recommend the implementation of differentiated human activities regulation measures in different biomes to promote global habitat restoration.

First, do no harm? Dark logic models, social injustice, and the prevention of iatrogenic conservation outcomes

In medicine and public health, the Hippocratic injunction to ‘first do no harm’ has inspired a longstanding tradition of research and practice seeking to mitigate iatrogenic (doctor or practitioner-created) risks. Aiming to anticipate and prevent iatrogenic outcomes, dark logic models challenge practitioners to explicitly consider mechanisms through which harms may arise from the implementation of proposed interventions. Placing recent literatures on conservation (in)justice in closer dialogue with debates about the utility of dark logic models in the health sciences, this article explores how such approaches may or may not be useful for avoiding negative social impacts or injustices in conservation governance. Particularly considering resurgent spatial ambitions in global biodiversity conservation – as evidenced by the Half Earth and 30 × 30 conservation targets – we suggest that dark logic models may ultimately prove to be a worthwhile component of conservation practice vis-à-vis the UN Convention on Biological Diversity's Kunming-Montreal Global Biodiversity Framework. In this context, dark logic models constitute an additional tool – which can be used in complementary fashion, alongside others – to better anticipate and prevent conservation harms, as well as to avoid further burdening those who have done the least to cause the biodiversity crisis with conservation's negative socioeconomic impacts.

Spatial identification of lost-and-found carbon hotspots at Javanese rice systems, Indonesia

CONTEXTAgricultural landscapes play a crucial role in global carbon sequestration and biodiversity conservation. The presence of trees outside forests has been recognized as a significant carbon pool, but it is crucial to acknowledge that these trees serve purposes beyond being a carbon sink. This study focuses on integrating border trees and home gardens as distinct land use classes in Indonesian Javanese agricultural land to assess their impact on carbon stock potential and biodiversity connections. OBJECTIVEThe objective is to classify and quantify the tree composition of these classes, estimate their carbon stock potential, analyze plant species diversity, and identify the ecological connections between home gardens and field borders. METHODSTo achieve this, high-resolution multispectral and Synthetic Aperture Radar images were used from four sampling areas covering 100 km2 each in Lamongan and Malang districts, East Java, Indonesia, for land cover/land use mapping. The land use function method was used to identify border trees and home gardens as separate land use classes. Carbon stock potential was estimated based on tree cover composition, while plant species diversity was analyzed through field surveys and farmer focus group discussions. RESULTS AND CONCLUSIONSCrops with border trees cover approximately 28% to 48% of the cropland area in the study sites, while home gardens represent about 74% to 85% of the settlement area. This suggests a potential to double tree presence in these sites by adopting border trees and home gardens practices across the entire area. The median tree cover ratio was around 27% for border trees and 33% for home gardens. This stratification approach identified 31% to 50% more carbon stock compared to calculations using standard classes. Furthermore, home gardens and border trees show a positive correlation with species richness, indicating their role as keepers of biodiversity. Therefore, home gardens and border trees could serve as a sustainability indicator for agricultural land in the Javanese farm system. SIGNIFICANCEThis research contributes to sustainable agricultural practices and climate change mitigation. The stratification approach of identifying border trees and home gardens offers a cost-effective approach for the better computation of carbon stock and can lead to effective land use policies and conservation measures that promote ecological resilience. The study provides valuable insights for similar agricultural contexts worldwide, guiding efforts toward a more sustainable agricultural future.

Challenges to Implementing the Kunming-Montreal Global Biodiversity Framework

The Convention on Biological Diversity (CBD) has been a pivotal international instrument for global biodiversity conservation since 1992. The recent Kunming-Montreal Global Biodiversity Framework (GBF) aims to provide a pathway for the CBD for the present decade. However, the practicalities of land use and biodiversity conservation pose significant challenges. Drawing from diverse literature and reports, we identify nine implementation challenges for the GBF. These encompass harmonising conservation with sustainable development, integrating local values and indigenous knowledge, adopting a holistic landscape approach, and prioritising effective local governance. A shift from broad targets to explicit conservation metrics is vital. We propose strategies emphasising building institutional capacity for localised, participatory conservation and policy-making processes. This article offers suggestions for improving the GBF’s implementation and shaping future policy frameworks.

Groundwater is a hidden global keystone ecosystem.

Groundwater is a vital ecosystem of the global water cycle, hosting unique biodiversity and providing essential services to societies. Despite being the largest unfrozen freshwater resource, in a period of depletion by extraction and pollution, groundwater environments have been repeatedly overlooked in global biodiversity conservation agendas. Disregarding the importance of groundwater as an ecosystem ignores its critical role in preserving surface biomes. To foster timely global conservation of groundwater, we propose elevating the concept of keystone species into the realm of ecosystems, claiming groundwater as a keystone ecosystem that influences the integrity of many dependent ecosystems. Our global analysis shows that over half of land surface areas (52.6%) has a medium-to-high interaction with groundwater, reaching up to 74.9% when deserts and high mountains are excluded. We postulate that the intrinsic transboundary features of groundwater are critical for shifting perspectives towards more holistic approaches in aquatic ecology and beyond. Furthermore, we propose eight key themes to develop a science-policy integrated groundwater conservation agenda. Given ecosystems above and below the ground intersect at many levels, considering groundwater as an essential component of planetary health is pivotal to reduce biodiversity loss and buffer against climate change.

Assessing the impact of river connectivity on fish biodiversity in the Yangtze River Basin using a multi-index evaluation framework

The Yangtze River Basin, the world's third-largest river basin and a hot spot for global biodiversity conservation, is facing biodiversity crisis caused by reduced river connectivity. The deterioration arises from four dimensions: longitudinal, lateral, vertical and temporal. However, limited research has quantified the spatiotemporal connectivity of the Yangtze River Basin and further evaluated the consequent impact on fish biodiversity. In our study, a multi-index evaluation framework was developed to assess the variations in the four-dimensional connectivity of the Yangtze River Basin from 1980 to 2020, and fish biodiversity affected by reduced connectivity was detected by environmental DNA metabarcoding. Our results showed that the Yangtze River Basin suffers from a pronounced connectivity reduction, with 67% of assessed rivers experiencing deteriorated connectivity in recent years. The lost fish biodiversity along the river reaches with the worst connectivity was likely attributed to the construction of hydropower plants. The headwaters and the downstreams of most hydropower plants had a higher fish biodiversity compared with reservoirs. The free-flowing reaches in the downstream of the lowest hydropower station, had higher lotic fish abundance compared with that in the upstream. As for the entire Yangtze River Basin, 67% of threatened fish species, with 70% endemic species, were threatened by reduced river connectivity. Our result indicates that the massive loss of river connectivity changes the spatiotemporal patterns of fish community and threatens protected fish. More effective measures to restore the populations of affected fish in rivers with reduced river connectivity are required.

Assessing the conservation effectiveness of the World’s protected areas: A habitat quality and human activities perspective

The World’s Protected Areas (WDPA) have been established for more than 100 years and serve an essential role in global biodiversity conservation. Assessing the conservation effectiveness of the WDPA is important for understanding the current status of global biodiversity conservation and formulating corresponding improvement measures. However, previous studies still lack to assess the conservation effectiveness of the WDPA at a global scale with a human activities and habitat quality perspective. Here, we construct a framework for evaluating conservation effectiveness from the perspective of human activities and habitat quality, and attempt to assess the conservation effectiveness of the WDPA. The study results found that habitat quality in the WDPA has not degraded over the past two decades and that human-land relationship have been further harmonized. However, trends in the impact of human activities on habitat quality varied across analytical models. The findings of this study affirm the conservation effectiveness of the WDPA but also raise some vigilance, which can provide scientific advice for policymakers further to improve the differentiated protective measures of the WDPA.

Effects of human depopulation and warming climate on bird populations in Japan.

Quantifying biodiversity trends in economically developed countries, where depopulation, associated secondary succession, and climate warming are ongoing, provides insights for global biodiversity conservation in the 21st century. However, few studies have assessed the impacts of secondary succession and climate warming on species' population trends at a national scale. We estimated the population trends of common breeding bird species in Japan and examined the associations between the overall population trend and species traits with the nationwide bird count data on 47 species collected from 2009 to 2020. The overall population trend varied among species. Four species populations increased moderately, 18 were stable, and 11 declined moderately. Population trends for 13 species were uncertain. The difference in overall trends among the species was associated with their habitat group and temperature niche. Species with relatively low-temperature niches experienced more pronounced declines. Multispecies indicators showed a moderate increase in forest specialists and moderate declines in forest generalists (species that use both forests and open habitats) and open-habitat specialists. Forest generalists and open-habitat specialists also declined more rapidly at sites with more abandoned farmland. All species groups showed an accelerated decline or decelerated increase after 2015. These results suggest that common breeding birds in Japan are facing deteriorating trends as a result of nationwide changes in land use and climate. Future land-use planning and policies should consider the benefits of passive rewilding for forest specialists and active restoration measures (e.g., low-intensive forestry and agriculture) for nonforest specialists to effectively conserve biodiversity in the era of human depopulation and climate warming.