Data from: Cross-realm incidental and cobenefits in freshwater and terrestrial biodiversity conservation planning

Freshwater species face greater threats than terrestrial ones;
however, conservation efforts for freshwater species lag far
behind those for terrestrial ecosystems. Traditionally,
conservation planning is often implemented independently for terrestrial
and freshwater realms, ignoring potential incidental conservation benefits
and cobenefits across them. We established datasets of terrestrial and
freshwater species in the Three Parallel Rivers Region, predicted their
distributions using Biomod2, applied Marxan Connect to identify priority
conservation areas (PCAs) for each group and evaluated their
incidental conservation benefits and cobenefits. Terrestrial PCAs were
concentrated in mountain valleys (e.g., Gaoligong and Cangshan Mountains),
while freshwater PCAs were clustered along four major
rivers and lakes. Despite low correlations in irreplaceability
(r = 0.34–0.45, p <0.001) and limited spatial
similarity (Jaccard = 0.35–0.43), both PCA types yielded incidental
benefits and cobenefits. Each PCA protected ≥ 80% of species and 52% of
area in its own realm, while incidentally covering ≥ 79% of
species and 42% of area in the other. Notably, terrestrial PCAs protected
more freshwater species, whereas freshwater PCAs covered larger
area for terrestrial species. Importantly, the greatest cross-realm
cobenefits were achieved by the TS–FS PCAs, which yielded the highest
coverage for both terrestrial (88.35% and 62.02%) and freshwater species
(81.71% and 56.77%) and exhibited a strong synergistic relationship
(y = 0.24x1.31, R2 = 0.85), while featuring overlapping
PCAs that protected the highest proportions of species (80.45–91.28%) and
area (46.25–63.04%) across taxonomic groups. Synthesis and
applications. Single-realm planning can yield cross-realm
cobenefits, demonstrating strong potential for integrated conservation
strategies. Integrating these cobenefits into cross-realm planning is key
to advancing the “30×30” biodiversity targets.