1 Introduction

Worldwide ecosystems are deteriorating at an alarming rate, and more than 1 million plant and animal species are facing the risk of extinction (IPBES 2019). Global loss of biodiversity, with an average of 69% decline, has been reported between 1970 and 2018 due to the dual crisis of climate change and biodiversity loss (WWF 2022). A decline of 47% has also been reported with respect to global natural ecosystems, followed by a 75% alteration in the land surface and 85% in wetlands. Land-use/land-cover changes have severely impacted terrestrial and freshwater ecosystems since 1970 (IPBES 2019). These observations were further supported by the IPBES-IPCC combined report, which reported 77% of land area and 87% of ocean area being modified by human impact (Pörtner et al. 2021). Loss of biodiversity and ecosystem degradation have created a positive feedback loop for even more drastic climate change consequences (Mooney et al. 2009). The UN Decade for Ecosystem Restoration (2021–2030), with the aim to halt and reverse ecosystem degradation and support sustainable productions and local livelihoods, was declared an extension of the Bonn Challenge for Forest Landscape Restoration and Land Degradation Neutrality by UNCCD (Dhyani et al. 2022a). Renewed attempts to ensure global efforts for achieving conservation of biodiversity are made through the Kunming-Montreal Global Biodiversity Framework, especially Targets 1, 2, and 3, which aim to bring the loss of ecosystems to zero by 2030, ensure appropriate restoration and conservation measures taken for the ecosystems (CBD 2022).

Ecosystems are part of life-support systems and provide goods and services with quantifiable value (Cowx and Portocarrero Aya 2011; Elmqvist et al. 2012). While ecosystems are critical for their biophysical value and functions, recent studies additionally indicate the existing links between biodiversity, ecosystem services, and human well-being (Cardinale et al. 2012; Sandifer et al. 2015; Ament et al. 2017; Pradhan and Khaling 2023), and healthy ecosystems have a significant role to play in this context (Costanza et al. 2022). Evaluating the status of the ecosystems is of serious consideration for a country as populous and biodiverse as India, considering ecosystem health assessment using RLE is a headline indicator for target A of GBF and will be required to mainstream in upcoming National Biodiversity Strategy and Action Plans (NBSAPs) produced by the country.

2 Biological Diversity and Significance of Red Listing of Ecosystems for India

India is home to rich biodiversity and a variety of landscapes and ecosystems ranging from mountains to deserts, and tropical evergreen forests to coral reef ecosystems and having important biodiversity hotspots (Space Applications Centre 2016). However, the country is experiencing rapid loss of biodiversity and ecosystems (Dhyani et al. 2022a). Nearly 30% or 98.7 million ha of total geographic land has been degraded or faced desertification (Space Applications Centre 2016). India has four biodiversity hotspots and high conservation-value ecosystems: the Himalayas, Indo-Burma, the Western Ghats, and the Sundaland. Indo-Burma is regarded as one of the most threatened of the World’s 36 biodiversity hotspots (CEPF 2020). The recent State of Forest Report by the Forest Survey of India (FSI 2021) found that the North-eastern states of Arunachal Pradesh, Manipur, Nagaland, Mizoram, and Meghalaya witnessed the largest forest cover loss in the country in the last two years (2019–2021). A study (Chaturvedi et al. 2017) found that about 50% of the forests in Meghalaya experienced increased disturbance from 2000 to 2016. The condition in the Himalayan ecosystems is even critical as they are threatened by diverse drivers, with an increased probability of loss of endemic species and natural ecosystems (Dhyani 2023). The dramatic increase in forest fires across Indian forests, increased temperatures, and erratic rainfall patterns have led to increased habitat destruction and loss of ecosystem structures and functions (Roy et al. 2015).

Key ecosystems in India are affected by continuously increasing human interference and increasing climate vulnerability. For instance, in biodiversity hotspots, the forest covers of 77% of Western Ghats–Sri Lanka, 99% of Indo-Burma, and 75% of the Indian Himalayan Region are already lost to diverse direct and indirect drivers of biodiversity loss (Singh and Kushwaha 2008; Dhyani et al. 2022a), followed by 47% decline in evergreen semi-evergreen forests in Kerala region of Western Ghats by 1998 (Prasad 1998). Even future projected changes estimate a reduction in the distribution of endemic plants in the biodiversity hotspots across India (Chitale et al. 2014). Increased vulnerability of forests in the Himalayas, parts of the Western Ghats and Central India (Chaturvedi et al. 2011; Dhyani et al. 2022b), and extinctions of endemic species and subspecies of various taxa in the Himalayas by 2100 present an alarming situation (Pandit et al. 2007; Dhyani et al. 2020). In Central India, tremendous development pressures have impacted the remaining refugees and wildlife corridors of the typically dry deciduous forest ecosystem with a human-dominated agricultural matrix (Schoen et al. 2022; Srivathsa et al. 2023).

The grasslands of the Terai region are part of a unique ecosystem, with grass species amongst the tallest in the world and maintained by annual flooding. All the iconic large mammals of the country and some of the most threatened species of birds use this sensitive ecosystem as their habitat. There has been a drastic reduction of these ecosystems by transitions into woodland as well as through human-induced land-use changes (Banerjee et al. 2023). The tree-covered freshwater wetlands Myristica swamps in the Western Ghats, considered primaeval ecosystems, are known to act as a sponge and source of water for several streams supporting diverse ecological and social requirements of the region. Unfortunately, they now exist as fast-depleting small, isolated pockets and are one of the most threatened ecosystems in India (Ranganathan et al. 2022). Conservation of blue carbon has also been emphasised in the coastal zones where sensitive ecosystems such as mangroves and seagrasses are being lost, resulting in a decline in the fisheries-based economy (Kadaverugu et al. 2021; Das and Santhanam 2022). Country-wise, India holds the highest number of threatened species in the Indo-Malayan Relm (Sivadas 2020). Projected climate change in the twenty-first century increases the risk of impaired ecosystem services resulting in reduced human well-being (Ashutosh et al. 2020). Habitat loss in biodiversity-rich areas may also be a crucial concern for the spread of zoonotic diseases (Walsh et al. 2019).

While species Red Listing has been an important approach by the IUCN Species Survival Commission since 1964, it has not been possible to assess the status of species and red list them timely as many species were threatened and even went extinct before they were discovered (https://www.iucnredlist.org). Hence, an umbrella approach that helps assess the ecosystem health was considered crucial to provide blanket protection to ecosystems as a sensitive habitat and flora and fauna residing in the ecosystem (Rodríguez et al. 2012).

Human well-being and ecosystem well-being are interlinked via diverse important ecosystem functions or ecosystem services. Alongside the provisioning and cultural services, the regulation and supporting ecosystem services are important to maintain balance in the environment and ensuring resilience in the changing climate conditions. These services, however, are often undervalued and mostly ignored (Dasgupta 2021). Certain undervalued ecosystems like mangroves, wetlands, salt marshes, and seagrasses are important carbon sinks (Banerjee et al. 2017; Ganguly et al. 2018; Bal and Banerjee 2020). Mangrove ecosystems, along with carbon sequestration, provide cushion to tropical cyclones (Bhargava and Friess 2022; Bimrah et al. 2022). The importance of certain ecosystems spans beyond their immediate environment; for example, diverse ecosystems in the Himalayas are important for downstream communities and even global processes (Joshi and Joshi 2018; Dhyani et al. 2022b). IUCN RLE tool is a proven asset in factoring in the ecosystem services to direct immediate actions and aids in conserving often overlooked but high conservation-value ecosystems.

3 Current Trends in Red Listing of Ecosystems

With the growing global loss of ecosystems, it has become imperative to assess the health of ecosystems to prioritise conservation actions and ensure appropriate actions are undertaken to reduce biodiversity loss and restore them using Nature-based Solutions (Dhyani et al. 2022b; Manika et al. 2023). IUCN Red List of Ecosystems (RLE) following the global typology of ecosystems is helpful to assess ecosystem health to identify priority conservation areas (Sato et al. 2019; Dhyani et al. 2022a; Keith et al. 2022). Ecosystem Health Assessment following the IUCN Red List of Ecosystems (RLE) is an important, standardised, and tested approach for conducting transparent and reproducible risk assessments for assessing threats to ecosystems as well as their collapse in terrestrial, freshwater, as well as marine ecosystems at different tiers/levels as also evidenced through multiple assessments undertaken in Australia, Latin America, and Europe (Keith et al. 2022). The earlier global ecosystem assessments relied heavily on species matrices and land-cover proxies, which could only partially include the ecosystem’s functional aspects (Keith et al. 2022). Hence, the IUCN Global Ecosystem Typology based on the generalisation of the world’s ecosystem based on their species composition, functions, and drivers of threat is a tested, data-driven and appropriate approach (Keith et al. 2022). Classifying the ecosystems and assessing ecosystem health using RLE based on this typology has been globally considered an effective approach for creating a unified database to prioritise areas and share best practices and successful measures from one region to another (Keith et al. 2015).

The significance of RLE is recognised in the recently approved Kunming-Montreal Global Biodiversity Framework (GBF), 2023, for its incorporation in law and government regulatory tools, the listing of the threatened ecosystems to improve their status in legal protection, acts as an important tool in planning and expansion of protected areas, for informing decisions regarding the restoration investments (Rowland et al. 2020a; IUCN-CEM 2021). The Red List of Ecosystems uses the IUCN Red List Index for Ecosystems as the reporting index, which is one of the main indicators in the monitoring framework for the post-2020 Global Biodiversity Framework. Along with the size of natural ecosystems, their capacity for supporting ecosystem components, and Target 1, it is a headline indicator for Goal A. For GBF Target 2, 3, and 7, it also serves as a component or supplemental indicator (Rowland et al. 2020b; Nicholson et al. 2021). RLE has also been highlighted as a useful tool and indicator in the National Biodiversity Strategy and Action Plans in countries like South Africa and Norway, enabling smoother tracking and reporting for national and international biodiversity and environment goals and targets (Bland et al. 2018) and will be required in post-2022 NBSAPs of each country that is signatory and has ratified CBD.

So far, 4279 ecosystem assessments have been carried out in the world over. National assessments have been carried out in 60 countries, and sub-national assessments in 19 countries (IUCN-CEM 2022). While RLE was to be completed for the entire world by 2022, the pandemic brought a temporary break to this process, and post-pandemic approval of Kunming-Montreal GBF, it is now important to assess the remaining areas and ecosystems at a country level. Many of these are biodiversity hotspots, high conservation-value ecosystems and may be facing hidden collapse (Dhyani et al. 2022b).

In the IUCN programme for 2017–2020 and even later 2021–2025, South Asia has been considered a region requiring the greatest conservation needs among IUCN’s eight Statutory Regions. Further, India is reeling under tremendous loss and degradation of ecosystems, and ecosystem health assessments will be critical to address climate change, land degradation, biodiversity loss, and other issues (Singh and Kushwaha 2008). Hence, it is crucial to undertake and initiate pilot ecosystem health assessments in various high conservation-value ecosystems of the region. One of the RLE carried out for the Sundarbans mangroves assessed the ecosystem to be in the ‘Endangered’ category owing to continuous clearing of the mangrove forests over several decades and declining fish populations (Sievers et al. 2020), and similar attempts are required to be initiated to assess the health of other high-value high priority ecosystems across the country.

As seen from the global case studies, RLE can specifically help prioritise conservation areas and other aspects in India, along with other co-benefits (Fig. 1). This shall help create a robust database for policy interventions at various levels, from local to national. It can also inform the State Biodiversity Strategy and Action Plans (SBSAPs), and NBSAPs, and support better reporting of biodiversity assessments to international bodies like Convention on Biological Diversity (CBD), International Union for Conservation of Nature (IUCN), United Nations Convention to Combat Desertification (UNCCD), United Nations Environment Programme (UNEP), and United Nations Framework Convention on Climate Change (UNFCCC), and reporting on the progress towards Global Goals under the new Global Biodiversity Framework and also UN SDGs, especially SDG 13, 14, and 15 directly dealing with the loss of biodiversity and ecosystems. Considering the importance and benefits of RLE, ecosystem-level, national as well as biome-level ecosystem assessments are a crucial necessity, with a major focus initially on the most vulnerable ecosystems, especially hotspots.

Fig. 1
figure 1

Significance of Red Listing of Ecosystems (RLE)-based prioritisation for conservation areas in India. The figure shows the seven significant co-benefits of RLE, which can contribute more than assessing an ecosystem's conservation status to informed decision-making

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As per the IUCN Red List of Ecosystems, RLE comprises “five criteria for assessing the risk of ecosystem ‘collapse’”. The criteria are based on the principle that ecosystem risk is a consequence of the species that comprise them, their interactions, and the ecological processes on which they rely (Keith et al. 2013) (Fig. 2).

Fig. 2
figure 2

Criteria for ecosystem red listing and assessing threat levels (Adapted from (Keith et al. 2013)). The five scientific criteria are based on which an ecosystem is assessed to understand its risk of collapse as per available evidence

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4 Approach to be Followed for Red Listing of Ecosystems in India

Instead of a nationwide approach followed in regions like North America (Comer et al. 2022), a more focused approach can be followed in India that will be more beneficial. It is important initially to undertake pilot studies and analyse the gaps and challenges arising from them to help support future assessments. There have been studies for identifying the critical area (landscape prioritisation) in the country based on their vulnerability to climate change and anthropogenic stressors (Srivathsa et al. 2023) and vegetation map, and an essential component of the ecosystem and RLE has already been created (Roy et al. 2015) [this helped in understanding the shift and change in forest ecosystems from Champion and Seth (1968)], which is a much-needed base for delineating functional ecosystems [ecosystem functioning, which encompasses processes such as biomass production, resource regulation, energy flow, and interactions among biota, along with ecosystem properties like ecological processes and species traits, defines and sustains the identity of an ecosystem and shapes its responses (Keith et al. 2022)] in the country. Further, a recent work (Choksi et al. 2023) can help integrate the socio-economic and biophysical concerns in this approach to ensure that one of the mega but hidden drivers of socioeconomics in ecosystem health assessments bringing local concerns in the High Conservation Value Area (Brown et al. 2013). (Moktan et al. 2021) used criteria like species distribution, key ecosystems, cultural ecosystem services, and threats to identify priority areas for conservation at the state level (Sikkim). However, the functional classification of ecosystems is largely lacking for Indian ecosystems, which means that a collaborative approach rather than a single institutional approach will be practical and appropriate to strengthen partnerships and collaborations between different organisations working in important ecosystems, sharing their experiences and strengths that can benefit these initial pilots.

This paper highlights the collaboration and partnerships emerging between different organisations in India CSIR-National Environmental Engineering and Research Institute (NEERI), Kerala Forest Research Institute (KFRI), Birla Institute of Technology and Science (BITS Pilani), Network for Conserving Central India (NCCI), Aranyak, Indian Institute of Technology (IIT) Delhi, Ashoka Trust for Research in Ecology and the Environment (ATREE), and others, to attempt RLE in moist temperate mixed broad-leaved forests in Western Himalayas; Terai Grasslands; Myristica Swamps in Western Ghats; Evergreen forests, Goa; Central Indian Forests; Mangroves in East Coast; Coastal Wetlands; River stretches (Ganga Gomukh to Haridwar) as first pilots in the country. These ecosystems are threatened by diverse drivers of loss that include but are not limited to socio-economic factors, climate change, and habitat loss (Singh and Kushwaha 2008; Tewari et al. 2017; Santhanam et al. 2022; Sivadas et al. 2023; Choksi et al. 2023; Manika et al. 2023). Also, the presence of organisations working in these ecosystems for a longer time brings a ground understanding of authentic information from different contexts and concerns of these ecosystems.

A recent IUCN-CEM global Steering Committee meeting in India followed by an international master class workshop on the status of ecosystems in Asia and Ecosystem Health Assessments for evidence-based Nature-based Solution (NbS) applications organised at Kerala Forest Research Institute (KFRI), Peechi Kerala in March 2023 raised a common thought on the need for working towards the common goal of assessment of the status of ecosystems in the region, emphasising the need for developing a roadmap along with diagnostic model and collaboration of experts from different domains and networks for achieving the goal (Manika et al. 2023).

India, being a vast country with a range of different ecosystem types, also has certain challenges to undertaking ecosystem health assessments. This includes the requirement for intensive capacity building, the inaccessibility of certain ecosystems’ evaluation, and the lack of funding support. However, effective collaboration between stakeholders and public & private entities could enable us to move forward and overcome these barriers. Apart from implementing ecosystem health assessment using RLE, the effort is to build the capacity of researchers to strengthen the cooperation and ensure that ecosystem health assessments are undertaken for different ecosystems of the country at the ecosystem, national as well as biome levels, whatever suits local, regional, and transboundary conditions. Conducting RLE will also help set up continuous monitoring systems for regular updating of undertaken and ongoing assessments, along with collaboration and cooperation to identify the gaps and further addressing these gaps by scientific collaborators and partners who are capable and empowered with diverse tools and techniques required for ecosystem health assessments The process would enable establishing a network of researchers, academicians, students, and other stakeholders that can help address future conservation, restoration, and conflict resolution concerns too (Fig. 3).

Fig. 3
figure 3

Steps for implementing a nationwide RLE assessment [adapted from Comer et al. (2022)]. Five major steps are identified for the implementation of an assessment for understanding the ecosystem collapse, starting from defining an ecosystem based on Global Ecosystem Typology to setting up a continuous monitoring system for revisiting the assessments

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The ecosystem health assessment scientific network for India will be crucial to achieving: (a) functional mapping of ecosystems, (b) identification of priority areas and threats, (c) understanding of socio-economic drivers, (d) climate change impacts on the ecosystems, (e) generation of crucial data on biodiversity, ecological interactions, ecosystem services and overall planning and implementation of customised Nature-based Solutions (NbS) at a landscape level (Valderrábano et al. 2021), (f) status of flow of ecosystem services (tangible and intangible), and (g) set of ecosystem health indicators that are relevant for India. Mainstreaming RLE in the NBSAPs can help improve our understanding beyond spatiotemporal changes in ecosystems as followed so far and help us understand the impact of diverse drivers on ecosystem functions and support GBF and Other Effective area-based Conservation Measures (OECMs).

5 Conclusion

Considering the successful implementation of RLE in other continents, regions, and countries, its effective use in informed management activities, and in the face of climate emergency threatening the existence of ecosystems, biodiversity, and the resulting ecological functions. The six-step approach proposed here, tailored to the country context, will help in prioritising the actions and identifying and gauging the probability of range-wide collapse of high-value ecosystems. It is imperative that RLE initiated in pilots is further followed for other high conservation-value ecosystems of South Asia and countries in the Asian region, as it could be an invaluable tool for quantitatively assessing the health of regional ecosystems and biomes. Although challenging, RLE has been effective in safeguarding resources, combating climate change, ensuring sustainable development, and helping policymakers devise science-supported, evidence-based strategies and implement them effectively to support conservation and sustainable development. This also includes mainstreaming various targets and goals, including SDGs, targets under GBF, NBSAPS, Net Zero, and others.