October 30, 2025
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Preface
Please note: this is a reproduction of a peer-reviewed article published by the journal Earth’s Future (AGU – Advancing Earth and Space Sciences). This article is available under the Creative Commons CC-BY-NC-ND 4.0 license and permits non-commercial use of the work as published, without adaptation or alteration provided the work is fully attributed.
Citation: Alejo, C., Reed, G., & Matthews, H. D. (2025). Indigenous-led nature-based solutions align net-zero emissions and biodiversity targets in Canada. Earth’s Future, 13, e2025EF006427. https://doi.org/10.1029/2025EF006427
Authors
C. Alejo, G. Reed, H. D. Matthews
Publisher
Published by Earth’s Future (AGU – Advancing Earth and Space Sciences).
Abstract
Indigenous-led Nature-based Solutions (“Indigenous-led NbS”), such as Indigenous Protected Conserved Areas and Indigenous Guardians programs, may represent a unique opportunity to advance climate and biodiversity targets grounded in Indigenous self-determination. Previous studies have comprehensively explored the scope and potential environmental outcomes of Indigenous-led NbS. Here, we build on this literature to assess how government support for Indigenous-led NbS influences climate and biodiversity outcomes. Specifically, we estimate the contribution of Indigenous-led NbS funded by the federal Government of Canada in conserving carbon stocks and biodiversity across terrestrial ecosystems. Using geospatial analysis and quasi-experimental methods, our results indicate that Indigenous-led NbS are as effective as existing Protected Areas in terms of climate change mitigation and biodiversity conservation. Moreover, our results demonstrate that government funding for Indigenous-led NbS is associated with moderate yet significant avoided land use emissions relative to Protected Areas. Based on topic-modeling applied to Indigenous-led NbS descriptions, climate and biodiversity outcomes emerge from holistic approaches to governance, intergenerational knowledge exchange, and climate-biodiversity action. Thus, government funding to Indigenous-led NbS may align biodiversity and climate outcomes with some aspects of Indigenous self-determination. The long-term alignment of these outcomes will require extended and sustained funding as well as full recognition of the rights of Indigenous Peoples.
Plain Language Summary
Nature-based Solutions (NbS) aim to enhance nature to tackle pressing challenges like climate change and biodiversity loss. Across the globe, Indigenous Peoples are leading NbS (i.e., Indigenous-led NbS) such as Indigenous Protected Conserved Areas and Indigenous Guardians programs. Previous studies have explored their potential environmental outcomes. Our study builds on these studies to understand how government financial support to Indigenous-led NbS influences carbon storage in plants and soil and biodiversity conservation. We focus on Canada as it offers valuable insights about the ways substantial government support may influence Indigenous-led NbS. Our results show that Indigenous-led NbS carbon storage and biodiversity conservation outcomes are similar to existing Protected Areas. Moreover, government funding to Indigenous-led NbS was related to lower carbon emissions from land use change compared to Protected Areas. By analyzing Indigenous-led NbS project descriptions, we found that environmental outcomes emerge from reciprocal relationships between people and the natural world. For example, knowledge exchange between youth and elders is essential for environmental health. Overall, government support for Indigenous-led NbS may align climate and biodiversity benefits with some aspects of Indigenous self-determination, but these positive outcomes will only continue with long-term financial commitment and full recognition of Indigenous rights.
Key Points
- Indigenous Lands are as effective as existing Protected Areas in conserving carbon stocks and maintaining different aspects of biodiversity
- Government funding for Indigenous-led Nature-based Solutions is associated with moderate avoided land use emissions relative to Protected Areas
- A sustainable alignment of biodiversity, climate, social, economic, and cultural outcomes requires full recognition of Indigenous rights
1 Introduction
Indigenous Peoples steward significant portions of Protected Areas and intact ecosystems globally (Garnett et al., 2018). Given this extensive stewardship, international consensus acknowledges that addressing the interconnected climate and biodiversity crises require meaningful partnerships with Indigenous Peoples. The Kunming-Montreal Global Biodiversity Framework, for example, established specific targets to protect Indigenous Peoples’ rights and ensure their participation in decision-making while pursuing other ambitious targets, including the protection of 30% of land and sea by 2030 and moving toward the sustainable management of species (CBD, 2022). Similarly, the Paris Agreement states that climate change mitigation and adaptation actions should respect Indigenous rights and recognize the importance of Indigenous knowledge (UNFCCC, 2015).
Nature-based Solutions (NbS) have been framed as a potential pathway to connect Indigenous Peoples to global climate and biodiversity actions (Matthews et al., 2022; Reed et al., 2024; Seddon, 2022; Townsend et al., 2020). NbS involve working with and enhancing nature through protection, management and restoration actions to address biodiversity loss, climate change and other societal challenges (Chausson et al., 2020; Seddon et al., 2020). Grounded in the inseparability and reciprocal relationships of people and nature, Indigenous epistemologies are inherently Nature-based (Reed et al., 2024). Recognizing these unique approaches and contributions of Indigenous Peoples to climate and biodiversity actions has resulted in the introduction of the term Indigenous-led NbS (Vogel et al., 2022).
While the recognition of Indigenous-led NbS is recent, some government programs and policies have targeted Indigenous stewardship in environmental governance over recent decades. For example, Indigenous Guardians initiatives in North America, Australia, and Aotearoa (New Zealand) have integrated monitoring and management actions of species and ecosystems with processes of cultural revitalization and knowledge sharing (Reed et al., 2021). Indigenous Protected and Conserved Areas (IPCAs) around the world have partially recognized Indigenous governance and knowledge systems in the conservation and management of biodiversity (Borrini-Feyerabend et al., 2004; Tran et al., 2020). However, Indigenous-led NbS face significant challenges, including industrial development pressures, unresolved land rights, power imbalances in participation and decision-making, restrictive legislation, and financial instability (Kennedy et al., 2023). Despite the challenges, these initiatives represent an opportunity for holistic NbS that extend beyond specific environmental targets (Nalau et al., 2018; Reed et al., 2024). Thus, consistent policies and programs for Indigenous-led NbS may have an important role in supporting Indigenous Peoples actions for biodiversity and climate, while advancing social, economic and cultural outcomes (Artelle et al., 2019; Reyes-García et al., 2022).
Previous attempts have documented the potential and realized effects of Indigenous-led NbS initiatives on climate change mitigation and biodiversity protection. Some studies have highlighted the potential role of Indigenous-led NbS by estimating Indigenous Lands’ extensive carbon storage (Walker et al., 2014, 2020), species richness (Schuster et al., 2019), and ecological intactness (Fa et al., 2020; Garnett et al., 2018) relative to other forms of land tenure and across diverse ecoregions. Using quasi-experimental methods that control for confounders, others suggest that Indigenous Land governance avoids 1%–26% more deforestation (Nolte et al., 2013; Sze, Carrasco, et al., 2022; Vergara-Asenjo & Potvin, 2014), conserves 3%–33% higher carbon stocks (Alejo et al., 2021), and maintains 0.1%–5.2% higher ecological intactness (Sze, Childs, et al., 2022) than unprotected lands. Based on similar methods, another group of studies has estimated the realized effect of policies and financial incentives on Indigenous-led NbS. For instance, granting land jurisdiction to Indigenous Peoples reduces around 71% of deforestation in Peru (Blackman et al., 2017) and 66% in Brazil (Baragwanath & Bayi, 2020). Alejo et al. (2022) have shown that REDD+ (i.e., Reduced Emissions for Deforestation and Degradation) financial incentives in Indigenous and other local communities in Guatemala support 0.53–1.24 tC/ha*year of avoided emissions relative to Protected Areas and other forms of land tenure.
Here, we expand on this body of literature by examining how government support for indigenous-led NbS influences climate change mitigation and biodiversity targets relative to conventional Protected Areas. We assess the climate and biodiversity impacts of two Indigenous-led NbS funded by the Government of Canada (GC): the Indigenous Guardians Program (Government of Canada, 2023) IPCAs (Government of Canada, 2021). Focusing on Canada offers valuable insights of how substantial government support may influence Indigenous-led NbS outcomes to achieve climate change mitigation and biodiversity targets (Bishop et al., 2024; Indigenous Circle of Experts (ICE), 2018; M’s-it et al., 2021). To this end, we quantify the spatial-temporal patterns of carbon storage and a composite biodiversity index in Government funded and unfunded Indigenous Lands, as well as in conventional Protected Areas. Based on these geospatial assessment and quasi-experimental methods, we quantified the effects of government funding of Indigenous-led NbS on carbon storage and biodiversity relative to Protected Areas. Finally, we analyzed descriptions of Indigenous-led NbS initiatives using topic modeling to identify how climate and biodiversity outcomes align with Indigenous self-determination. Our results indicate that Indigenous-led NbS are as effective as Protected Areas in terms of carbon storage and biodiversity outcomes. Moreover, our results show that government funding for Indigenous-led NbS yields moderate yet significant avoided land use emissions relative to Protected Areas. Taken together, our results suggest that government funding for Indigenous-led NbS may align climate and biodiversity outcomes with some aspects of Indigenous self-determination.
2 Materials and Methods
2.1 Indigenous Lands and Protected Areas
Our study focuses on the effect GC Funded and Unfunded Indigenous Lands on carbon stocks and biodiversity relative to Protected Areas at the national scale (Figures 1 and 2). GC funding particularly refers to the five-year $500 million (CAD) commitment under the “Canada Nature fund” to support nature conservation initiatives since 2018 (Environment and Climate Change Canada, 2023a, 2023b). The commitment included the Indigenous Guardians program ($25 million) and funding for the establishment of Protected Areas ($300 million), including IPCAs. To identify GC Funded Indigenous Lands, we related the public database of Indigenous Guardians funded initiatives (Government of Canada, 2023) (Table S1 in Supporting Information S1) to proponents such as Indigenous governments, including councils and bands, or Indigenous organizations, boards, and societies to the Indigenous Peoples and communities’ profiles established by Crown-Indigenous Relations and Northern Affairs Canada (2022). The profiles allowed us to associate the proponents with reserves, land claims agreements, and other Indigenous Lands’ legislative boundaries (Government of Canada, 2022). Based on the Canadian Protected and Conserved Areas Database (Environment and Climate Change Canada, 2023a, 2023b), two IPCAs that were formally recognized in 2018 were included as government-funded Indigenous-Led NbS: Edéhzhíe Protected Area and Thaidene Nëné Territorial Protected Area. While the GC has funded more than 80 Indigenous Guardians pilot initiatives and planned the establishment of 60 IPCAs, we include in our analysis GC Funded Indigenous Lands between 2018 and 2020 that match the availability of carbon stocks and biodiversity data (2010–2020).
Within the spatial data set of Indigenous-led NbS, we analyzed their descriptions to identify how climate change and biodiversity outcomes align with Indigenous self-determination. Here, we refer to self-determination as aspects of Indigenous governance related to autonomy, sovereignty, and assertions of Indigenous nationhood (Von Der Porten, 2012) that are not exclusively dependent on states (Neville & Coulthard, 2019). To this end, we removed common terms such as “Indigenous”, “project”, and “monitor”; repetitive action verbs (e.g., strengthen, ensure, develop, understand); and terms referring to locations and Indigenous Nations. We then examined, through topic modeling, how the corpus of terms in the descriptions were associated across three general topics (Table S2 in Supporting Information S1). These number of topics provided a good balance of interpretability and model fit (Table S3 in Supporting Information S1) in the R package topicmodels (Grün et al., 2024).
After defining the spatial boundaries of GC Funded Indigenous-led NbS, the Canadian Protected and Conserved Areas database was used to determine the boundaries of Protected Areas established by 2010 that were not co-managed by Indigenous Peoples. These areas were defined as counterfactuals of Indigenous Lands. Other Indigenous Lands that were not funded by GC between 2018 and 2020 through the Indigenous Guardians and IPCAs initiatives were defined as unfunded Indigenous Lands and also compared to Protected Areas. We acknowledge that the legislative boundaries of Indigenous Lands defined in our study do not represent the traditional spatial extension of Indigenous land stewardship within what is currently known as Canada (Figure S1 in Supporting Information S1). Therefore, the effect of GC Funded and Unfunded Indigenous Lands on carbon stocks and biodiversity is highly conservative in our analysis.
2.2 Total Carbon Stocks and Land Cover Dynamics
Total carbon annual stocks and changes were estimated using biomass, soil organic carbon, and land cover maps (Table S1 in Supporting Information S1). Data sources included a 2010 global harmonized biomass carbon map (∼300 m resolution) from Spawn et al. (2020) and soil organic carbon data (∼250 m resolution) from Sothe et al. (2022), representing estimates from 2000 to 2019 averages at 30 and 100 cm of depth. To determine total carbon changes, ESA CCI annual land cover maps (Defourny et al., 2023) were converted to 9 IPCC classes following Hu et al. (2021). Class transitions before (2010–2017) and after (2017–2020) GC funding were used to estimate biomass and soil organic carbon changes separately (Table S4 in Supporting Information S1).
We calculated total carbon stocks losses, using the following approach. Vegetation-to-non vegetation (e.g., forest-urban) transitions resulted in a complete biomass loss. For vegetation-to-vegetation transitions, partial carbon losses were calculated as the difference between initial high-carbon vegetation (e.g., forest) and the ecozone average of low-carbon vegetation (e.g., grassland). We assumed soil organic carbon remained stable in vegetation-only transitions (W. Li et al., 2018; Noon et al., 2022). Using peatland maps (Xu et al., 2018), the transitions from high-carbon vegetation classes to agriculture or urban or bare land involved a carbon loss function in non-peat soils at 30 cm of depth and complete carbon loss in peat soils at 100 cm of depth (Noon et al., 2022; Poeplau et al., 2011).
Similarly, total carbon gains involved region-based estimates. Biomass gains were calculated using sequestration rates for boreal, temperate lowland, temperate mountain (Noon et al., 2022), and tundra regions (Rocha & Shaver, 2011). Soil organic carbon gains (e.g., agriculture to shrubland) were estimated using recovery functions in non-peat soils at 30 cm depth for temperate, boreal (Poeplau et al., 2011), and tundra regions (Loranty et al., 2014). The recovery functions in boreal and temperate peatlands corresponded to soil organic carbon estimates at 100 cm depth (Poeplau et al., 2011). Wetland-forest transitions were excluded due to potential classification errors and temporal transitions (Amani et al., 2021; N. Li et al., 2023). These changes in biomass and soil organic carbon from 2010 to 2017 and 2017–2020 were combined to create annual total carbon maps (Table S2 in Supporting Information S1) and to estimate annual stock changes (Table S3 in Supporting Information S1) at a 1 km resolution.
2.3 Composite Biodiversity Habitat Index
We estimated a composite biodiversity habitat index following Soto-Navarro et al. (2020) before and after the GC funding for Indigenous Lands started. This composite index combines local biodiversity (b) and regional ecological intactness (c) components. The local biodiversity component bi integrated species richness, species rarity, and local ecological intactness. The species richness and rarity derived from ∼300 m Area of Habitat Maps for mammals and birds based on IUCN’s red list species range data and ESA-CCI land cover (Lumbierres et al., 2022). Species richness summed species presence across grid cells (α diversity), while rarity weighted species presence relative to total occurrence. Both metrics were normalized and combined through a geometric mean (Si). The GLOBIO 4-Mean Species Abundance index (Ei) at ∼300 m resolution was used to estimate local ecological intactness (Kim et al., 2018). This β diversity measure reflects compositional turnover between disturbed and undisturbed lands. The previous estimates were resampled to a 1 km resolution and added to determine the local biodiversity component (i.e., bi = Si + Ei).
To determine regional ecological intactness (ci), we used the CSIRO-Biodiversity Habitat Index at 1 km resolution (Hoskins et al., 2020). This index estimates habitat conditions based on land cover and vascular plant species turnover and reflects the proportion of effective habitat remaining among grid cells with similar species composition before habitat transformation. The composite index combines the local and regional components as BI = bi × ci, highlighting areas of high local biodiversity and ecological intactness. Given the temporal availability of local (b) and regional (c) ecological intactness, the BI was estimated for 2010, 2015, and 2020 (Table S4 in Supporting Information S1). The BI change was estimated for the periods 2010–2015 and 2015–2020 (Table S5 in Supporting Information S1), assuming the latter would reflect biodiversity conditions after GC funding to Indigenous Lands started.
2.4 Matching Analysis and Generalized Additive Mixed Models
We performed Matching Analysis to control for the influence of environmental and socioeconomic confounders. Matching Analysis is a quasi-experimental method that removes heterogeneous observations, creating a subset of treatment and control observations with similar confounder values and, therefore, reducing the association of confounders with the treatment assignment and the outcome variable (Stuart, 2010). In our case, the observations corresponded to ∼1 km pixels where we determined land tenure (i.e., treatment variable), confounders (Table S5 in Supporting Information S1), total carbon stocks and the composite biodiversity habitat index (i.e., outcome variables) (Table S6 in Supporting Information S1). The treatment group corresponded to observations in GC Funded or unfunded Indigenous Lands, while the control corresponded to Protected Areas established before government funding started (i.e., 2010). Based on the treatment assignment, we matched either GC Funded or Unfunded Indigenous Lands to Protected Areas in the same ecozone and equivalent elevation, slope, population density, travel time to cities, and road distance. We used coarsened exact matching (Iacus et al., 2015) in the R package MatchIt (Ho et al., 2011) to determine equivalent value ranges for confounders. For example, a road distance between 0 and 5 km was considered equivalent. To assess the removal of heterogeneous observations, we compared the standard mean differences and Kolmogorov-Smirnoff statistics for all confounders before and after matching with the R package Cobalt (Greifer, 2021).
Based on the matched data sets, we fitted Generalized Additive Mixed Models (GAMMs) (Wood, 2017) in the R package mgcv (Wood, 2022). The GAMMs aimed to estimate the effect of GC Funded and Unfunded Indigenous Lands on carbon stocks and the composite biodiversity habitat index relative to Protected Areas (Table S9 in Supporting Information S1). For each outcome variable, we fitted a model including a fixed effect for land tenure comparisons (i.e., GC Funded vs. Protected Areas or Unfunded vs. Protected Areas), non-parametric interactions for confounders and geographic coordinates, and random effects. Regarding carbon storage models, the outcome variables were total carbon stocks in 2010, 2017, and 2020, and average annual changes before (2010–2017) and after (2017–2020) government funding. The biodiversity models included the biodiversity habitat index in 2010, 2015, and 2020, as well as average annual changes in the periods 2010–2015 and 2015–2020. The fixed effect determined whether an observation was an Indigenous Land (i.e., GC Funded or Unfunded), allowing us to quantify slope and intercept terms, representing the effects of Indigenous Lands and Protected Areas on the outcome variables, respectively. We spanned any remaining imbalances from the matched subset by adding non-linear smooth functions between the confounders and the outcome variables. These smooth functions were cubic regression splines set to a maximum of 3 knots (points joining different smooth functions). The models also included a spatial smooth function between observations’ longitude and latitude with the outcome variables, using 10 knots to directly account for spatial autocorrelation in the residuals (Keil & Chase, 2019). A random effect was included to account for the variation among groups of matched observations. The models comparing GC Funded Indigenous Lands and Protected Areas had an additional random effect accounting for the years of funding. Based on model-checking of residuals with different variable transformations and family distributions, we opted for a log transformation of annual carbon stocks variables, square root transformations of non-categorical confounders, and a Gaussian family distribution for the resulting 10 models. Consequently, the matching analyses and GAMMs allowed us to control for environmental (e.g., ecozone), socioeconomic (e.g., population density), and other confounders (e.g., years of funding) to estimate a low-bias and conservative effect of GC Funded and Unfunded Indigenous Lands on carbon storage and biodiversity relative to Protected Areas.
3 Results
3.1 Government Funded Indigenous-Led NbS in Canada
We identified 62 Indigenous Guardians programs and 2 IPCAs that were funded by the GC between 2018 and 2020. At least 20 initiatives involved multiple Indigenous governments or organizations and were distributed across 649 Indigenous land boundaries. Among these GC funded Indigenous-led NbS, 57 were implemented by First Nations and 7 by Inuit. While some guardians programs were led by Métis, we were not able to precisely identify their spatial boundaries. Regarding Indigenous Guardians programs, 40 programs were funded for a year, 17 for two years, and 5 for three years. Based on the descriptions provided by those Indigenous governments or organizations leading the programs, most of these Indigenous-led NbS aimed to strengthen local capacity for stewardship and monitoring actions in traditional lands and waters grounded in their knowledge, language, and culture. The topic modeling results suggested three main topics across these funded Indigenous-led NbS descriptions (Figure 3): (a) land and water governance, where stewardship, management, and conservation actions were related to Indigenous governments, local youth, and regional coordination; (b) a focus on climate change adaptation that connected youth and elders to protect lands, waters, and biodiversity; and (c) knowledge exchange processes (e.g., training, education) linking elders and youth with lands’ and waters’ health, conservation, management, and wildlife. These topics suggest that climate and biodiversity actions in GC Funded Indigenous Lands rely on holistic approaches to governance, climate change adaptation, and intergenerational knowledge exchanges.
3.2 The Spatial Patterns of Indigenous Lands and Protected Areas
We identified the spatial patterns of carbon storage and biodiversity (Table S5 in Supporting Information S1), along with environmental and socio-economic confounders (Table S6 in Supporting Information S1) in Indigenous Lands and Protected Areas. Before some Indigenous Lands were funded by GC (ca. 2017), the average total carbon stocks (i.e., biomass and soil organic carbon) were higher in Protected Areas (524.07 ± 495.27 tC/ha) than in unfunded (479.44 ± 446.83 tC/ha) and GC Funded (253.79 ± 287.67 tC/ha) Indigenous Lands (Figure 4). In contrast, the biodiversity habitat index in 2017, which comprises species richness, rarity, and ecological intactness, was relatively higher in GC Funded Indigenous Lands (0.73 ± 0.042) compared to unfunded Indigenous Lands (0.69 ± 0.15), and Protected Areas (0.68 ± 0.10). These differences in carbon storage and biodiversity seem explained by the confounders. Overall, Protected Areas are widely distributed in the latitudinal and longitudinal gradient of ecozones (Table S7 in Supporting Information S1) and provinces (Table S8 in Supporting Information S1) across ∼2.2 million km2 (Figure 5), representing varied mosaics of biodiversity, soil, and geological features. The unfunded Indigenous Lands covered 0.27 million km2 and exhibited a broader range of ecozones than GC Funded Indigenous Lands, which covered 0.49 million km2, mostly in the highly intact northern Taiga and Artic ecozones. Besides the spatial distribution across ecozones, other environmental and socioeconomic confounders highlight differences among these land tenures. Relative to Protected Areas, GC Funded Indigenous Lands were 56% and 23% more distant to cities (3,600 ± 1,803.70 min) and the road network (79 ± 59 km), respectively (Figure 6). Unfunded Indigenous Lands had a mean population density five times higher than Protected Areas (0.16 people/km2)). Given these disparate spatial distributions, Indigenous Lands and Protected Areas are not directly comparable in terms of carbon storage and biodiversity.
3.3 The Effect of Indigenous Lands and Government Funding on Carbon Storage and Biodiversity
After matching GC Funded and Unfunded Indigenous Lands to Protected Areas with equivalent environmental and socio-economic confounders (Figure 6), we quantified their differences in carbon stocks and the biodiversity habitat index through GAMMs. This approach that controlled for confounders, including funding duration, revealed low-bias and conservative estimates of Indigenous land stewardship on climate change mitigation and biodiversity. As a baseline, we quantified differences in carbon stocks and the biodiversity composite index before GC funding for Indigenous-led NbS started (ca. 2017) (Figure 7). Compared to Protected Areas, GC Funded Indigenous Lands showed 4% higher carbon stocks (264 tC/ha, p < 0.001) (Table S10 in Supporting Information S1), while those unfunded had 8.7% higher carbon stocks (282 tC/ha, p < 0.001) (Table S11 in Supporting Information S1). The biodiversity composite index displayed minimal differences between Protected Areas and GC Funded (+2%, p < 0.001) and unfunded (−1.7%, p < 0.001) Indigenous Lands. Thus, after controlling for confounders and before Government funding started, Indigenous Lands displayed a similar climate change mitigation and biodiversity potential relative to Protected Areas.
When considering changes before and after GC funding (i.e., 2018), all Indigenous Lands, regardless of government support, displayed negligible reductions in the composite biodiversity index (<−0.0005, p < 0.001). These reductions were similar to Protected Areas (Figure 8). In contrast, carbon stocks changes resulted in varying effects partially attributable to GC funding. Before receiving government funding (i.e., 2010–2017), GC Funded Indigenous Lands resulted in moderate gains in carbon (0.07 tC/ha*year, p < 0.001) that were smaller than Protected Areas (0.09 tC/ha*year, p < 0.001) (Table S10 in Supporting Information S1). During the government funding period (i.e., 2017–2020), both GC Funded Indigenous Lands and matched Protected Areas experienced carbon stocks losses. However, these losses were 2.8 times lower in GC Funded Indigenous Lands (−0.04 tC/ha*year, p < 0.05) than in Protected Areas (−0.11 tC/ha*year). In other words, GC Funded Indigenous Lands resulted in avoided emissions relative to Protected Areas during the funding period 2017–2020. As a reference, unfunded Indigenous Lands and matched Protected Areas experienced non-significantly different gains in carbon stocks (∼0.11 tC/ha*year, p > 0.5) in 2010–2017, but the latter showed greater gains in 2017–2020 (∼0.16 tC/ha*year, p < 0.001) (Table S11 in Supporting Information S1). Taken together, we did not identify significant changes in biodiversity attributable to GC funding in Indigenous Lands. However, our results indicate that funding for Indigenous-led NbS is associated with mitigating carbon stock losses relative to Protected Areas, suggesting that government support for Indigenous governance may contribute to avoided land use emissions.
4 Analysis
4.1 Indigenous-Led NbS Contributions to Climate and Biodiversity
Our study assessed the effect GC Funded and Unfunded Indigenous Lands on carbon stocks and biodiversity relative to conventional Protected Areas. We have focused on federal government support for the Indigenous Guardians IPCAs since 2018. Our results contribute to the accumulating body of evidence highlighting the key role of Indigenous land stewardship in climate change mitigation and biodiversity conservation (Bishop et al., 2024). Similar to findings in the tropics (Walker et al., 2014, 2020), we show that Indigenous Lands maintain carbon stocks comparable to Protected Areas. These climate benefits are evident in Unfunded Indigenous Lands, which resemble the spatial distribution of Protected Areas across high-carbon ecoregions, including temperate and boreal forests. Our assessment extends beyond biomass to include soil organic carbon, revealing the crucial role of Indigenous Lands in protecting peatlands and other irrecoverable carbon stocks that, if lost, will not recover by 2050 (Noon et al., 2022).
Regarding biodiversity, previous studies have estimated Indigenous stewardship across 36% of global intact forests (Fa et al., 2020). Schuster et al. (2019) identified that Indigenous Lands outperformed species richness in Protected Areas from Brazil, Australia, and Canada. By implementing a composite index that integrates estimates of intactness with species richness and rarity (Soto-Navarro et al., 2020), our results show that Indigenous Lands contribute to different aspects of biodiversity. Therefore, Indigenous governance could complement the role of existing Protected Areas in terms of climate change mitigation, biodiversity, and ecological representation. According to socio-economic and environmental confounders, this role is not limited to remote areas but extends toward accessible and more densely populated areas in southern provinces, challenging fortress conservation approaches (Domínguez & Luoma, 2020). Instead, Indigenous Lands provide an understanding of conservation that supports the relational interaction between people and place (Artelle et al., 2019).
After controlling for confounders, GC Funded and Unfunded Indigenous Lands were as effective as Protected Areas on carbon storage and biodiversity. This low-bias and conservative effect suggests an intrinsic effect of Indigenous Lands governance that is not explained by environmental and socio-economic confounders. Previous findings from the tropics have suggested a similar effect on avoided deforestation (Blackman et al., 2017; Nolte et al., 2013; Sze, Carrasco, et al., 2022; Vergara-Asenjo & Potvin, 2014), carbon stocks (Alejo et al., 2021, 2022; Blackman & Veit, 2018), and ecological intactness (Sze, Childs, et al., 2022) relative to unprotected lands. Using Protected Areas rather than unprotected lands as counterfactuals, our analysis shows that Indigenous Lands can achieve substantial climate and biodiversity benefits. These benefits from Indigenous governance, consistent across varied environmental and socio-economic contexts, emerge from unique forms of knowledge of lands and waters, adaptive management practices, customary laws, and place-based values (Artelle et al., 2019).
Although most GC funded Indigenous Lands received funding for only a year, these incentives are associated with moderate avoided emissions relative to Protected Areas. Previous findings on Indigenous guardians and IPCAs reveal mechanisms through which funding translates into tangible climate and biodiversity benefits (Reed et al., 2021). For example, the Wahkohtowin Indigenous Guardians program in Ontario (Canada) has contributed to initiatives such as improved forest management with landscape conservation planning or herbicide alternatives with moose recovery and monitoring (Powell et al., 2024). IPCAs, like Thaidene Nëné in the Northwestern Territories (Canada), demonstrate how sustained government funding enables long-term Indigenous-led NbS. In this case, First Nations governments implement management plans rooted in Indigenous worldviews and laws supported by guardians trained in both Indigenous science and Western science (Nitah, 2021). Consequently, government support for Indigenous governance may contribute to enforcing impactful conservation, management, and monitoring actions with quantifiable effects in the short term. Currently, there is a partially realized climate and biodiversity potential through GC Funded Indigenous Lands, but guaranteeing sustained funding and including unfunded Indigenous Lands is pivotal for long-term climate and biodiversity benefits.
4.2 The Limitations of Carbon and Biodiversity Assessments for Indigenous-Led NbS
Estimating carbon storage and biodiversity outcomes in Indigenous-led NbS presents diverse challenges. While our results demonstrate that land cover monitoring effectively tracks carbon stocks changes, biodiversity monitoring through a composite index change proved more complex. We found no significant biodiversity changes following government funding, which may reflect limitations in our measurement approach. The composite index would only account for ecological intactness changes, representing only 50% of the composite index value. Additionally, the intactness measures are either estimated in reference to anthropogenic pressures (Kim et al., 2018) or the total remaining habitat for species in a cell (Hoskins et al., 2020). At our study’s 1 km resolution, certain land cover transitions, such as forest to shrubland, may register as carbon stock losses without necessarily affecting intactness measures. Future biodiversity assessments would benefit from integrating area of habitat maps and land cover changes with habitat quality and connectivity metrics across diverse taxonomic groups and at high resolutions (Arce-Plata et al., 2025). Improving assessments is essential for accurately representing the relationship between Indigenous Peoples and biodiversity (Fernández-Llamazares et al., 2024). In any case, these remote-sensing-based carbon storage and biodiversity estimates are conservative and complementary to monitoring actions in the field. Beyond these technical limitations, such measurements do not capture other outcomes rooted in the holistic relationships of Indigenous Peoples with their lands and waters. These relational outcomes could be better assessed through complimentary research, including qualitative and Indigenous-led approaches.
4.3 Indigenous-Led NbS and Indigenous Self-Determination
Our analysis of GC Funded initiatives’ descriptions exhibits the holistic nature of Indigenous-led NbS and some of their social and cultural outcomes. As stated in previous work (Reed et al., 2024), these initiatives extend beyond climate change mitigation and biodiversity conservation to encompass broader and reciprocal relationships between people and nature. Using Reed et al. (2022) policy analysis framework, we find that government-funded Indigenous Guardians Programs and IPCAs may support some aspects of Indigenous self-determination. First, Indigenous-led NbS aim to enable Indigenous governments to connect local rightsholders’ values and priorities with regional and Government stakeholders’ decision-making processes. This holistic approach to environmental governance may advance Indigenous Peoples’ effective participation (Artelle et al., 2019; Reed et al., 2022).
Indigenous-led NbS may contribute to other aspects of self-determination. For example, these initiatives facilitate knowledge exchange by connecting elders with youth or Indigenous and Western knowledge systems to manage lands, waters, and wildlife. Such exchange processes help preserve Indigenous knowledge while enabling it to work “side-by-side” with Western knowledge in environmental governance (M’s-it et al., 2021; Reed et al., 2022). Furthermore, Indigenous-led NbS address climate change by recognizing its connection to biodiversity loss and implementing actions guided by intergenerational knowledge exchange. This approach toward the climate and biodiversity crisis creates opportunities to achieve social, economic, and cultural outcomes, advancing Indigenous rights (Reed et al., 2021). Determining the exact effect of these outcomes is beyond the scope of our study. Nonetheless, our findings suggest that government funding of Indigenous-led NbS may support climate and biodiversity outcomes as well as some aspects of Indigenous governance, knowledge exchange, and rights. Furthermore, the effectiveness of Indigenous holistic approaches to NbS demonstrates why financial frameworks should expand beyond environmental metrics to recognize local values and support social and cultural benefits.
Despite federal funding, significant barriers prevent the full expression of Indigenous-led NbS, and thus, Indigenous self-determination. We have shown that youth-elders and indigenous-western knowledge exchanges are fundamental components of Indigenous-led NbS. Nevertheless, significant legislative and epistemic barriers limit the ethical engagement of Indigenous Knowledge in NbS. For instance, traditional fire management practices are frequently discarded to follow governments’ directives (Reed et al., 2021) and only gain temporary consideration during post-wildfire crises (Nikolakis et al., 2024). The absence of ethical treatment of Indigenous knowledge limits the ability of Indigenous governments to contribute to environmental governance and decision-making. Such limitations highlight a fundamental tension in government-funded Indigenous-NbS: the absence of recognition of Indigenous jurisdiction over the land.
Recognizing the full jurisdiction and authority of Indigenous Peoples, including land rights, such as IPCAs in Canada (Mansuy et al., 2023; Vogel et al., 2022), has been one of the most effective pathways for aligning self-determination with climate and biodiversity outcomes (Baragwanath & Bayi, 2020; Benzeev et al., 2023; Blackman et al., 2017). However, most of the Indigenous Guardians programs analyzed here correspond to federally recognized boundaries that do not account for the customary land governance of Indigenous Peoples. Federally recognized boundaries not only represent a methodological limitation of our study but also a tangible barrier to Indigenous self-determination as well as climate and biodiversity outcomes. For example, Indigenous Guardians programs, such as the Coastal Watchmen program in British Columbia, can’t fully exercise monitoring and enforcement actions due to jurisdictional limitations (Coastal First Nations – Great Bear Initiative, 2022). At a deeper level, the unwillingness to recognize Indigenous jurisdiction represents a continuation of the government’s assumption of sovereignty over Indigenous Lands. In response to this absence of recognition, some Indigenous organizations have pursued self-determination initiatives (Cameron et al., 2019) and legal actions to assert Indigenous laws (Listuguj Mi’gmaq Government, 2021). Therefore, recognizing Indigenous jurisdiction is fundamental to achieving biodiversity and climate outcomes enabled by Indigenous Peoples’ knowledge systems and effective participation in environmental governance.
5 Conclusions
Our results support a growing consensus about Indigenous-led NbS′ pivotal role in aligning biodiversity, climate, social, economic, and cultural outcomes. Through key improvements on previous research, including tracking biomass and soil organic carbon emissions and assessing biodiversity through a composite index, we provide a conservative estimate of Indigenous-led NbS contributions to climate and biodiversity in Canada. Our results demonstrate that Indigenous Lands are as effective as existing Protected Areas in conserving carbon stocks and maintaining different aspects of biodiversity. These results imply that supporting Indigenous-led NbS could strategically complement the role of existing Protected Areas while advancing both the Kunming-Montreal Global Biodiversity Framework targets and greenhouse gas emission reduction commitments under the Paris Agreement’s Nationally Determined Contributions. Our results also indicate that government funding for Indigenous-led NbS, such as IPCAs and Indigenous Guardians, is associated with moderate avoided emissions relative to Protected Areas. To realize long-term climate and biodiversity benefits, government funding needs to be sustained in current Indigenous-led NbS and extend to unfunded Indigenous Lands.
Finally, we identify that Indigenous-led NbS emerge from reciprocal relationships between Indigenous Peoples and the natural world, fostering holistic approaches to governance, knowledge exchange, and climate-biodiversity action. These approaches ultimately contribute to climate and biodiversity outcomes as well as Indigenous self-determination. Thus, government funded Indigenous-led NbS could advance Indigenous Peoples’ effective participation and engagement of knowledge in decision-making. However, a sustainable alignment of biodiversity, climate, social, economic, and cultural outcomes requires full recognition of Indigenous rights, including land rights.
Acknowledgments
This work has been supported by a Natural Sciences and Engineering Research Council of Canada (NSERC) Alliance Grant with Microsoft (ALLPR 571271-21). C.A. was supported by the Horizon Postdoctoral fellowship at Concordia University.
Conflict of Interest
The authors declare no conflicts of interest relevant to this study.
Data Availability Statement
All input data used in the analyses are publicly available (Agriculture and Agri-Food Canada, 2023; Crown-Indigenous Relations and Northern Affairs Canada, 2022; Defourny et al., 2023; Environment and Climate Change Canada, 2023b; Government of Canada, 2023; Hoskins et al., 2020; Kim et al., 2018; Lumbierres et al., 2022; Natural Resources Canada, 2011, 2023; Noon et al., 2022; Sothe et al., 2022; Spawn et al., 2020; Statistics Canada, 2011; Weiss et al., 2018; WorldPop & CIESIN – Columbia University, 2020; Xu et al., 2018). The geospatial data sets generated for this study were not released publicly to respect the privacy of Indigenous organizations and lands analyzed in our study. For inquiries about access to these data sets, please reach out to Graeme Reed (greed@afn.ca) for further information. The code and resulting models’ statistics supporting this study are available in Alejo et al. (2025).