A social–ecological geography of southern Canadian lakes

To assess the three components of the socio-ecological geography of Southern Canada, data were collected or retrieved from three large-scale national datasets: (1) lake biophysical and chemical characteristics, from the NSERC Canadian Lake Pulse Network—Lake Survey (Huot et al. 2019), (2) threat level, from the World Wildlife Fund (WWF) Canada—Watershed Reports (2017), and (3) recreational uses as ES, from Statistics Canada—Survey on the Importance of Nature to Canadians (Special Surveys Division 1996). We chose these datasets because they were at the national scale and standardized across that scale. For example, other ES could have been explored, such as drinking water, but that information is heavily fragmented across jurisdictions.

The ecological component of our assessment included the novel use of information generated by the Lake Pulse Network Lake Survey in considering how lakes within distinctive lake regions deviated from reference conditions. The social component of our assessment included information derived from the WWF Watershed Reports (2017) on threats to surface waters (https://watershedreports.wwf.ca/#intro), and data from Statistics Canada on in-land water recreational use. WWF did a comprehensive analysis of human-driven threats to surface waters at the watershed level across the country, where information for 167 different sub-watersheds was used. Pressures assessed in that report were similar to those linked to ecosystem status as well as recreational ES in Grizzetti et al. (2016). Finally, we incorporated a quantitative assessment of recreational ES use of lakes across Canada as another social metric. ES use was corrected for the current population and considered realized; we did not assess demand for services (potential use or projected use), although we anticipate that with climate change, demand will increase. The socio-ecological framing of the work presented borrows from theoretical approaches suggested in the literature (Villamagna et al. 2013; Grizzetti et al. 2016), but with a more spatially explicit and quantitative component similar to Martín-López et al. (2017). Although the loss of recreational services would have an economic cost to many regions across Canada (Fisheries and Oceans Canada 2019), we did not incorporate the economic value of these ES in this assessment (Jones et al. 2016).

Based on threats to drinking water sources and aquatic ecosystem health identified by Environment Canada (Environment Canada 2001), WWF's 2017 Watershed Report (WWF-Canada 2017) developed seven indicators of the most significant threats currently facing Canada's watershed, namely pollution, habitat loss, habitat fragmentation, overuse of water, invasive species, flow alteration, and climate change. Among the seven threat indicators reported by the WWF, we selected five that apply to lakes (pollution, climate change, invasive species, overuse of water, and habitat loss). Flow alteration and habitat fragmentation were discarded in part because these threats apply more to rivers, as well as some of the built-in redundancy of some of these indicator threats. The remaining five indicators were calculated based on more specific sub-indicators that are of growing regional concern: pollution includes point-source pollution, pipeline incidents, transportation accidents, and agricultural contamination risks from nitrogen, phosphorus, and pesticide release; habitat loss includes LULC as well as forest loss; overuse of water indicates the ratio of water withdrawal to water supply; invasive species indicates the presence of invasive species; and climate change includes summer and winter temperature anomalies and spring and summer precipitation anomalies.

The presence and magnitude of these threats were assessed in 167 sub-watersheds of Canada's 25 Pearse watersheds (WWF-Canada 2015). The data were originally gathered by the WWF to establish a relative ranking of threats across the country. Threat categories (ranging from “none” to “very high”) for individual indicators were defined according to a regular interval classification system (WWF-Canada 2015). For more details on the methods, see WWF's 2017 Watershed Report “Threat methodology” (https://watershedreports.wwf.ca/#intro). We used the average threat score for the five chosen indicators in the 167 sub-watersheds to capture as much variation as possible. Although sub-watershed scores were presented as threats to rivers, the report explicitly states that the same level of threat applies to lakes and wetlands located within these same sub-watersheds.

Statistics Canada conducted the Survey on the Importance of Nature to Canadians among 87,000 Canadians aged 15 years and older in 1996. This survey assessed the social and economic value that Canadians place on nature-related recreational activities (Environment Canada 1999). Of interest to our study is the “water and recreation” theme of this survey, which provides information on four freshwater recreational uses, including participation in (1) swimming and beach activities, (2) sport fishing, (3) canoeing, kayaking, and sailing, and (4) power boating. The metric we applied to assess ES use in this study is participation measured as days per km² of major drainage area for these four recreational water activities. Participation was calculated by major drainage area (11 in Canada): Maritime Provinces, St. Lawrence, Northern Quebec and Labrador, Southwestern Hudson Bay, Nelson River, Western and Northern Hudson Bay, Great Slave Lake, Pacific, Yukon, Arctic, and Mississippi as defined by the Standard Drainage Area Classification (Natural Resources Canada 2003). Data on recreational use were adjusted to reflect today's population in each major drainage area by multiplying the use frequency by the ratio of the current population (2016 census) to the one in 1996. A composite score was based on the sum of the measured participation in the four recreational services.

When low-impacted lakes were considered using LDA, we observed a considerable amount of overlap, suggesting similarities in morphometric and chemical properties among lakes in certain ecozones (Fig. S3). Overlap generally occurred between adjacent ecozones and within a common physiographic region (Fig. S1). For example, lakes in the Prairies, Boreal Plains, and Taiga Plains ecozones, all from the Interior Plain physiographic region, had similarly high Secchi depth, high conductivity, and reduced watershed slope. This suggested that these ecozones could be merged into a large lake region with shared physical and chemical baseline conditions (see Table S1). Based on the amount of overlap observed in the LDA reflecting shared properties among ecozones and on physiographic spatial proximity, we aggregated several ecozones into five “lake regions” (Fig. 2a). These were renamed from west to east as the “Pacific” (n = 69), the “Mountains” (n = 137), the “Plains” (n = 165), the “Continental” (n = 220), and the “Atlantic” (n = 68) lake regions (Fig. 2b). The LDA performed with the new lake regions was more robust, where the two first canonical variates explained 49% and 40% of the total variance, compared to 52% and 29% for the LDA among the original ecozones. Attribution of lakes to their group (ecozone or lake region) was also improved by using the discriminant functions of the new aggregated lake regions. The classification was correct, with a mean of 85% using the lake region as the grouping when compared to 76% when using ecozones (Table S2). Table 2 describes the variability of the unimpacted reference lake conditions for each lake region.

The LDA discriminant function indicated that altitude, mean watershed slope, colour (A440), DOC, and conductivity were the variables that best distinguished lake regions (Fig. 2a and Tables S3 and S4). We observed that Pacific lakes were generally deep (highest mean depth and low dynamic ratios), unproductive (high Secchi depth, low TN, low TP, low Chl a, and low DOC), and with steep catchment slopes. Mountain lakes were typically quite clear (high Secchi), contained little Cl⁻, and were, unsurprisingly, generally located at much higher altitudes. In contrast, Plains lakes were located within shallow catchments and were the most naturally productive and ion-rich lakes. Indeed, baseline values of TN, TP, DOC, and conductivity were twice as high as in other regions, but Secchi and SUVA254 were the lowest. Lakes in the Continental region generally exhibited median values falling in the middle of the distribution of most variables. Atlantic lakes tended to be small and shallow (second lowest mean depth and high dynamic ratio), located at low altitudes, and rather coloured (high A440) with low conductivity. Also, the Atlantic was the only region where pH was acidic (<7) for most lakes. Conditions of reference lakes in some regions—TN in the Plains for example—were higher than those considered high in all other regions. As such, regional reference conditions need to be established rather than a national average when assessing the deviation for lake ecological state or relative lake health (Table 2).

To characterize the deviation of lakes from reference conditions, we compared how the morphometric, chemical, and land-use characteristics of highly impacted lakes deviated from the low-impact ones (Fig. 3). These deviations were calculated using region-specific z-scores, allowing us to compare the direction and/or magnitude of changes among lake regions. For morphometry, impacted lakes generally had lower values compared to reference (Fig. 3a), indicating that these lakes tended to be shallower, smaller, had shallower watershed slopes, lower drainage and dynamic ratios, and were located at lower altitudes. The Plains region was an exception to this trend, as most morphometric variables had positive deviations, and impacted lakes tended to be larger with higher drainage and dynamic ratios and located at higher altitudes. Other exceptions were observed in the Pacific region (higher dynamic ratio) and in the Atlantic (deeper lakes with a steeper slope). Finally, while all morphometric variables from impacted lakes in the Continental region were similar to reference, there were large differences for some variables in other regions, namely the much lower slope in the Pacific, the much lower altitude in the Mountains, and the much lower dynamic ratio in the Atlantic.

For the deviation of chemical variables, we visualized nutrients, Chl a, and Secchi separately from variables related to changes in carbon (DOC and spectral properties), pH, and ions (Figs. 3b and 3c, respectively). TP and Chl a, which are classically used to characterize eutrophication, were higher in impacted lakes for several regions but not all (Fig. 3b). Concentrations in the Mountain and Atlantic regions were similar to reference, and although there was an increase in TP in the Plains, there was no corresponding increase in Chl a. Secchi, which is also classically used to assess eutrophication, was lower in impacted lakes in all regions except in the Atlantic, where it was on average higher, and as such, highly impacted lakes were counterintuitively more transparent. TN, however, increased rather strongly and consistently across all regions. Fluctuations in nutrients were also observable in the relative changes in N:P ratios, where regions responded rather differently. When C:N and C:P ratios were considered, the responses were equally divergent. If TN increased in all cases and DOC stayed the same, the ratios should have all decreased. This, however, was not always the case, as DOC increased regionally in impacted lakes in the Pacific region, decreased in the Atlantic, but remained unchanged in the others (Fig. 3c). Spectral measures of A440 and SUVA254, which represent coloured and terrestrial DOC composition, respectively, were largely similar between lakes of low and high impact, with some notable decreasing trends in both the Atlantic and Mountain Regions and an increasing trend of A440 in the Pacific. Cl⁻, conductivity, sulphate, and pH increased consistently across all regions in impacted lakes, but the magnitude of the response for Cl⁻ was the strongest.

Across regions, not surprisingly, differences in land use for highly impacted lakes were driven predominantly by increasing agriculture or urban expansion in their watersheds (Fig. 3d). Urban expansion was the main anthropogenic change across all regions except for the Plains, where agriculture was most dominant. Mountain and Continental lakes were strongly affected by both drivers, whereas the Atlantic and Pacific were primarily impacted by urban development. We used a PCA to look for correlations among the deviations from reference lakes of different variables across regions (Fig. 4). This allowed us to determine more generalized patterns of changes in chemical variables in response to changes in physical and land-use features. Axis one separated impacted lakes between those influenced by changes in urban areas and those influenced by agricultural land use. Compared to the latter, lakes impacted by urban expansion in their watershed tended to be smaller, clearer, with lower nutrients, located at lower altitudes, and associated with increasing Cl⁻ concentrations. Those impacted by agriculture and pasture tended to be shallower and had higher drainage and sediment dynamic ratios, with higher TP, TN, Chl a, and DOC concentrations. As Cl⁻ tended to be more indicative of an urban signal and TN, one of agriculture, and both had a consistently strong deviating response across all regions (Figs. 3b and 3c and Fig. S4), we used both these variables as our indicators of altered lake ecological state.

Using TN and Cl⁻ as indicators of human impact, we created a national map of lake ecological state based on sampled lakes (Fig. 5a). Altered lakes were scattered across Canada, but dense clusters were observed in Southern Ontario and across the Prairies. Regional patterns in lake state attributed to either Cl⁻, TN, or a combination of both emerged (see individual maps of lake state based on Cl⁻ or on TN; Fig. S5). Newfoundland, Nova Scotia, Northern Ontario, and the Vancouver area were predominantly altered due to Cl⁻, while alteration in the central part of the Prairies (Manitoba, Saskatchewan, and Alberta) was attributable to TN. The alteration in the middle of British Columbia, the southern part of the Prairies, Southern Ontario, and the Lower St. Lawrence in Quebec was due to a combination of both. The northern regions (Northern British Columbia, Alberta, Saskatchewan, and Quebec) and Western Ontario showed little change in lake state.

Threat levels (Fig. 5b) were higher in the southern part of Canada, which coincides with higher population densities. However, northern areas were also subject to threats, mainly climate change and habitat loss. The highest overall threat levels were found around the Great Lakes and in the southern part of the Prairies. In these regions, all of the threats considered were present at a very high level. Exceptions were habitat loss and climate change in Southern Ontario (moderate level) and for invasive species in the Southern Prairies (low level). Regions within the St. Lawrence watershed were the only ones affected by water overuse, whereas pollution level was a widespread threat, particularly along the border with the United States (WWF-Canada 2017).

Recreational use (Fig. 5c) was highest in Eastern Canada, followed by the West Coast. Participation in terms of days/km² of watershed in all four categories of recreational ES (swimming and beach activities, sport fishing, power boating, and paddle and sail boating) was highest in the St. Lawrence Drainage Area (Quebec, Newfoundland, and Southern Ontario). In the Maritimes Provinces, participation was also very high in most ES categories, except for power boating. In the Pacific Drainage Area (British Columbia and a part of Alberta), all ES categories were popular, particularly for sport fishing and swimming, but participation in days/km² of watershed was lower than in Eastern Canada. Use in the Nelson River Drainage Area (Prairies) was low compared to the other three regions, but fishing and swimming were the most popular ES in that region. In the less densely populated northern regions, overall use of recreational ES was low, with sport fishing as the main ES (Environment Canada 1999).

On the composite map (Fig. 5d), the dominant colour in Eastern Canada changes from purple in the north to magenta in the south, reflecting the high recreational ES use (blue) in this region, with threat level (red) intensifying from north to south. We also note the presence of cyan patches in Southern Quebec and Nova Scotia, particularly around Quebec City and Halifax respectively, implying the presence of altered lakes actively used for recreation. The tip of Southern Ontario appears in white, indicating that lakes were altered, threatened, and intensively used. In Western Canada, similar colour gradients as in the East emerged, but shades tended to be darker. This suggests that the same components (recreational uses and threat level) were present, but at lower levels compared to the East. The threat level also intensifies on a north–south gradient in the west, from Whitehorse to Vancouver. The few diffuse green spots indicate areas where lakes were particularly altered. In Southern Manitoba, the red to orange colour suggests that despite the strong presence of threats, the lakes in this region have suffered minimal alteration compared to their reference state. In Southern Saskatchewan, however, the yellowish colour indicates significant levels of threat and lake alteration. In the middle of these two provinces, there is a light green clump signifying the alteration of several lakes, but with a lower threat level than those located to the south. Recreational use does not emerge in these regions, as the level of participation was considered low compared with the rest of Canada. The main colour obtained in Northern Canada (Northern Quebec and Ontario, Northern Saskatchewan and Alberta, and Northwest Territories) was dark brown, indicating a low level of threat, little to no recreational use, and low levels of lake alteration.

Understanding how severely a lake is altered by human activities in its watershed requires the knowledge of reference conditions prior to those changes. Spatial differences in the underlying geology that influence the topography, morphometry, and land cover will likely create regionally distinct lake references (Boyce 2015; Read et al. 2015), which are essential to characterize when carrying out comparisons at the continental scale (Cheruvelil et al. 2013). The stratified design of LakePulse sampling, which included a series of low or unimpacted lakes across most of the country, allowed us to determine these reference conditions (Huot et al. 2019). We found that unimpacted lakes from several Canadian ecozones adjacent to one another with shared physiography had similar morphometric and chemical reference traits. Landscape and watershed characteristics such as elevation and mean slope were the most important variables in discriminating lake properties between regions, followed by conductivity, DOC, and, to a lesser extent, nutrients. This finding highlights the role of physiography in creating lake regions across Canada (Boyce 2015), suggesting that climate and vegetation type related to ecozones had less of an overall influence on reference lake physical and chemical characteristics.

The deviation of highly impacted lakes from their regional reference allowed us to evaluate which chemical variables were most consistent in capturing a lake's response to anthropogenic changes in its watershed. Most regions behaved as expected and experienced cooccurring higher concentrations of TN, TP, and Chl a, with reduced Secchi due to increased turbidity (Minns et al. 2008; Webster et al. 2008) and land-use changes (Carpenter et al. 1998; Nielsen et al. 2012). However, higher TN in impacted lakes was more consistently observed across the lake regions and was not always accompanied by higher TP and Chl a or transparency loss. Increases in TP, and as a consequence algal biomass, may have been dampened in regions where urban expansion was dominant due to legislative reductions from point-source sewage inputs or well-managed septic systems (Budd and Jones 1978; Schindler 2006). One exception was the naturally P-rich region of the Prairies (Table 2), where, despite a significant increase in both nutrients, the increase in Chl a was not as marked. This could be explained by a threshold response of Chl a to increasing TN (Filstrup et al. 2018). Another possible explanation of why TN was more indicative of human impact in the watershed is the relatively higher applications of N as compared to P fertilizers on agricultural lands (Glibert et al. 2014; Goyette et al. 2016) or inputs from atmospheric N deposition (Elser et al. 2009). Excessive N inputs relative to P in conditions when both are high is cause for concern as higher N:P ratios tend to favour the establishment of more toxic species of algae and cyanobacteria (Leavitt et al. 2006; Scott and McCarthy 2010; Glibert et al. 2014; Taranu et al. 2017), which impinge on multiple valuable aquatic ES.

Another striking and consistent difference between human-impacted and reference lakes among regions was higher Cl⁻ concentrations. In northern freshwaters, this increase in Cl⁻ concentrations is primarily attributed to road salt used for de-icing during winter, which explains why it was most associated with urbanization in the watershed (Chapra et al. 2009; Canadian Council of Ministers of the Environment 2011; Dugan et al. 2017). Regions with the highest road salt use in Canada are Southern Ontario, Quebec, and the Maritimes (Environment Canada and Health Canada 2001; Evans and Frick 2001), and salt application is also reported to be high in the Prairies (Morin et al. 2000), consistent with our observations of altered Cl⁻ concentrations in these regions (Fig. S5a). The environmental impact of increased Cl⁻ concentration in lakes is of growing concern, particularly with changing climate conditions where warmer average winter temperatures and changes in precipitation may require more salt for de-icing (Kaushal et al. 2021). High levels of Cl⁻ can have adverse effects on aquatic life, with chronic toxicity occurring at 250 mg/L (Evans and Frick 2001) and recent experimental work showing adverse effects and shifts in community composition at even lower Cl^- concentrations, highlighting the need to downscale toxicity levels even further (Hébert et al. 2022; Hintz et al. 2022). Increased salinization may also impact physical lake properties, including stronger and more prolonged stratification, with cascading repercussions on major biogeochemical cycles (Kaushal et al. 2005; Dugan et al. 2017). As such, increased Cl⁻ concentrations may influence the provisioning of several ES, including sport fishing. However, the overall consequences of increased salinization on lake ecosystem functioning and services remain underexplored. Regardless, Cl⁻ was the strongest human indicator of urban expansion, whereas TN was both an agricultural and urban indicator. Both TN and Cl⁻ can render drinking water unpotable due to concerns around human health and taste, respectively (Kaushal et al. 2005; Howard and Maier 2007; Karimi et al. 2020), making their combined deviation a good proxy for assessing the altered lake ecological state and vulnerability to provide different ES.

Beyond the clear patterns of TN and Cl⁻ increase in impacted lakes, we also found some regional anomalies in the deviations from certain chemical variables. For example, impacted lakes in the Atlantic and mountain regions were clearer than reference lakes on average, with a higher or unchanged Secchi depth. As Chl a concentrations in impacted lakes were similar to those in reference lakes, this enhanced water clarity could be explained by lower coloured DOC (A440, Brezonik et al. 2019). A possible influence on this loss in colour is the photobleaching of CDOM, which can increase water transparency (Del Vecchio and Blough 2002; Kalff 2002). Overall, lakes from the mountain region are on average deeper and at higher altitudes (Table 2), whereas impacted Atlantic lakes, morphometrically, tend to be deeper with a lower sediment-dynamic ratio (Fig. 3). For both, this would result in longer water residence times, favouring photobleaching. Indeed, in terms of morphometric, topographic, and landscape variables, most impacted lakes tended to be near or lower than reference lakes (with the exception of the Plains), but each region has its peculiarities. One overarching tendency is that impacted lakes across multiple regions were more accessible to human populations. This includes impacted Pacific, Mountain, and Atlantic lakes that were at lower altitudes, similar to what has been reported elsewhere (Ebner et al. 2022). In the case of the Pacific region, impacted lakes had much shallower watershed slopes than unimpacted ones and were presumably easier to develop on. In the Plains, Pacific, and Continental regions, impacted lakes were generally smaller and shallower, making them more vulnerable to changes in the landscape due to higher internal loading and reduced volume (Nõges 2009). Impacted lakes in the Plains had both higher drainage and dynamic ratios, resulting in a higher proportion of terrestrial inputs (Kalff 2002) and a greater proportion of the water in contact with sediments (Håkanson 1982), respectively. These physical features combined could explain the slightly higher colour in the impacted lakes of this specific region, as their physical properties make them inherently more vulnerable to human pressure.

To create the first social–ecological geography of lakes in southern Canada, we developed an innovative framework that spatially links regional lake ecological state, emerging lake threats, and recreational ES use. By colour-coding ecological and social gradients, the RGB composite map (Fig. 5) allowed us to visualize hotspots of aquatic ecosystem vulnerability and ES conservation. This approach clearly identified areas where lakes were used by people and where there was a risk of losing recreational ES due to threats or lake degradation. From the perspective of preserving recreational ES, the colours of interest were white (high alteration, threats, and use), cyan (high alteration and use), and magenta (high threats and use), where use coincided with an altered lake state and/or threat. This first broad-scale national attempt suggests that locations expressing these colours should be considered priority areas for restoration or for monitoring as a precaution to ensure ES will not be lost over time.

Through this framework, we found that populated urbanized areas were of greatest concern. The southern tip of Ontario, which includes the Greater Toronto Area and accounts for nearly 20% of the country's population (Canada Population 2021), appeared in white on the map due to a combination of lakes being intensively altered, threatened, and used. Other areas of concern include the Lower St. Lawrence River between the cities of Montreal and Quebec and the Halifax region in Nova Scotia, which all exhibit a colour approaching light cyan, indicating high recreational use combined with an altered lake ecological state and a moderate threat level. All these urban locations should be monitored, as a degraded lake state could potentially lead to the loss of lake services. The same colour combinations were found in British Columbia around the cities of Vancouver and Victoria. However, according to the data we had, recreational use on the West Coast was lower, which resulted in the altered lake ecological state (in lighter green) emerging as a more prominent component overall. Areas coloured magenta were found in southeastern Ontario, southern Quebec, and the lower part of British Columbia. Here, recreational use and threat levels were high, but lakes, on average, are not yet significantly degraded. As such, management efforts should be implemented now to maintain their current healthy state. Finally, in the Plains, particularly around Saskatoon, Saskatchewan, and Edmonton, Alberta, lakes were altered and threatened by growing agriculture and urbanization, even though recreational ES use is low.

We believe our approach is valuable in identifying priority areas for ES and aquatic ecosystem protection, and the results presented here should be considered a proof of concept. One of the benefits of our proposed framework is that it is very flexible in that it can be applied at different scales of inquiry, with a focus on more regional threats of concern where applicable (for example, mining, logging, or wildfires), and assess the use of different ES than the ones used here. It also provides a striking visual representation that is relatively easy to understand. The approach may be most useful to management and stakeholders at smaller regional or local scales of inquiry, where information on a broader suite of ES valued by local communities may be available or more quantitatively robust. The challenge, perhaps at smaller scales, is assessing the deviation of a lake's ecological condition from baseline. However, the latter could be taken from a broader context of spatial assessment (i.e., the Lake Region presented here), whereas threats and use could be quantified more locally (Martín-López et al. 2017).

One limitation to our study is that our indicators of altered lake ecological state, TN and Cl⁻, do not necessarily impinge directly on the delivery of the four recreational services assessed here but may act as a proxy for some. For example, Health Canada's Guidelines for Canadian Recreational Water Quality (2012) related to swimming have threshold values for cyanobacteria and E. coli related to the risk to human health in the case of direct contact with skin. High concentrations of TN are known to promote toxic algal and cyanobacterial blooms (Glibert et al. 2014; Monchamp et al. 2014; Taranu et al. 2017) and are indirectly linked to the loss of this ES. Similarly, Cl⁻ may, through food web effects (Dugan et al. 2017; Hintz et al. 2022), influence sport fisheries, although that remains underexplored. A more appropriate ES to assess with nitrate (as part of TN) and Cl⁻ is the loss of drinking water, as increasing concentrations of both can render water unpotable due to human health concerns and taste, respectively (Kaushal et al. 2005; Howard and Maier 2007; Karimi et al. 2020), but we did not find easily accessible data around that ES across Canada.

There were also several limits to the recreational ES dataset we used. First, it was dated from 1996, and although adjusted for the current population, it is possible that recreational habits have changed over time and no longer accurately reflect current use. Second, the ES dataset covered broad watershed areas across the country and was not as spatially explicit as other components in our model. The recreational ES data were also only available in days of use per square kilometer of major watershed, which reflects the intensity of use over a given area, not the intensity of use by individuals. As such, whether the lakes assessed in Lake Pulse were actually used for these recreational ES is uncertain, although given the proximity of these lakes to roads, chances are more likely. Less densely populated areas are disadvantaged as use could be diluted by watershed size, where a sparsely populated area in which individuals use ES intensively can be equivalent to a densely populated area where individual use is infrequent. Furthermore, many of these sparsely populated areas are inhabited by First Peoples who were not considered in the census; given their intimate relationship with natural resources, we argue the need to prioritize the protection of ES for those nations that rely directly on them for provisioning (Berkes 1990; Islam and Berkes 2016).