Data

In Table 1, the yellow column contains the quarter section numbers, which are the observational units. Quarter sections are numbered from lowest to highest consolidation index score. In the blue columns are the predictor variable, the consolidation index, and the covariate, mean sampe salinity. Both the predictor variable and covariate are continuous. Mean sample salinity per quarter section was included in the analyses to separate its effect on water boatman species assemblages from the effect of pond consolidation. In green are the counts of individuals for each species of water boatman identified in the samples, pooled by quarter section. Species are grouped by migratory status based on a combination of literature (Srayko et al. 2022), what we observed in the fall samples, and collective personal observations by myself, John Acorn, and Stephen Srayko.

Table 1: Raw data by quarter section. Asterisks denote migratory water boatman species.

We sampled during a drought year. Total quarter section pond area ranged from 3.13–10.68 ha in the spring and 0.83–10.68 ha in the summer due to extensive drying of non-permanent ponds. All seasonal marshes that we encountered in the spring were dry in the summer, but we were able to capture seasonal, semi-permanent, and permanent shallow open water habitats in the Alberta Wetland Classification System (Alberta Environment and Sustainable Resource Development, 2015) in our samples. We were able to maintain a spread of consolidation index values with our 14 quarter sections, despite the drought (Fig. 12). Mean sample salinity ranged from 0.55–4.42 ppt, excluding quarter section 12, which was an outlier at 20.68 ppt (Fig. 12). Quarter section 12 was excluded from the final analyses. Notably, 12 contained an extremely high abundance of a salt-tolerant species, Trichocorixa verticalis (Table 1). Quarter section 14 contained a single pond, scoring a maximum CI value; however, this single pond was seasonal (drying up by the fall) in 2024, contradicting the intended behaviour of the consolidation index, and pond habitat that is within the total pond area range of this study (0.83–10.68 ha) should become more permanent as it is consolidated. Final analyses were performed excluding this quarter section. Notably, 14 contained a high abundance of migratory species (Table 1).

Figure 12: Boxplots of the consolidation index and mean sample salinity data.

In our 84 samples that we collected from 14 quarter sections, we examined and identified 8,110 individuals representing 18 species of water boatmen. Four species were collected from only one quarter section (Table 1). I included these four species in the analyses but their relationships to the predictor variables should be cautiously interpreted. Overall, Callicorixa audeni and Trichocorixa verticalis were the most common and abundant water boatman species in this study, with collections from 13 of 14 quarter sections and counts peaking at 1,293 and 12,314 adult individuals per quarter section, respectively (Table 1). I extrapolated counts over 500 based on subsample size following recommendations from Doğramaci et al. (2010). The species-level count data is positively skewed and zero-inflated, typical of this type of community data, and for which distance-based ordinations are suitable. Principal coordinates analysis ordinations of the quater sections according to the species-count data are provided in Figures 13. The species names are shortened to the fist letter of the genus and first three letters of the specific epithet; refer to Table 1 for the full species names. The species-counts were converted to Bray-Curtis distances before ordinating. Figure 13A includes all quarter sections, while Figure 13B excludes the outlying quarter sections 12, which had extremely high salinity, and 14, which contained a single, seasonal pond. In terms of water boatman species composition quarter sections 3, 10, and 12 are more similar to each other than to other quarter sections (Fig. 13A) and they had higher salinities than others (Table 1). Quarter sections 2, 5, 7, and 11 also have similar species compositions (Figs. 13A, 13B) and have lower salinities (Table 1). Quarter sections 6 and 8 also differ from the other quarter sections in species composition (Figs. 13A and 13B) and were located further south than the others, southeast of Red Deer, AB (Methods Fig. 9).

Figure 13: Principal coordinates anaylsis ordinations of all quarter sections (A) and quarter sections excluding 12 and 14 (B), with vectors for water boatman species-counts (converted to Bray-Curtis distances). Species in green are migratory, species in blue are non-migratory. Species codes are the first letter of the genus name and first three letters of the specific epithet. Refer to Table 1 for full species names. Quarter sections are numbered from lowest to highest consolidation index score (higher number = higher consolidation index score, see Table 1).

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