Assessing the conservation priority of freshwater lake sites based on taxonomic, functional and environmental uniqueness

Abstract

Aim:We propose a novel approach that considers taxonomic uniqueness, functional uniqueness and environmental uniqueness and show how it can be used in guiding conservation planning. We illustrate the approach using data for lake biota and environment.Location: Lake Puruvesi, Finland. Methods:We sampled macrophytes and macroinvertebrates from the same 18 littoral sites. By adapting the original "ecological uniqueness" approach, we used distancebased methods to calculate measures of taxonomic (LCBD-t), functional (LCBD-f) and environmental (LCEH) uniqueness for each site. We also considered the numbers and locations of the sites needed to protect up to 70% of total variation in taxonomic, functional or environmental features in the studied part of the lake.Results: Relationships between taxonomic (LCBD-t), functional (LCBD-f) and environmental (LCEH) uniqueness were generally weak, and only the relationship between macrophyte LCBD-t and LCBD-f was statistically significant. Overall, however, if the whole biotic dataset was considered, macroinvertebrate LCBD-f values showed a consistent positive relationship with macrophyte LCBD-f. Depending on the measure of site uniqueness, between one-third to one half of the sites could help protect up to 70% of the ecological uniqueness of the studied part of Lake Puruvesi. Main conclusions:Although the dataset examined originated from a large lake system, the approach we proposed here can be applied in different ecosystems and at various spatial scales. An important consideration is that a set of sites has been sampled using the same methods, resulting in species and environmental matrices that can be analysed using the methodological approach proposed here. This framework can be easily applied to grid-based data, sets of islands or sets of forest fragments. We suggest that the approach based on taxonomic, functional and environmental uniqueness will be a useful tool in guiding nature conservation and ecosystem management, especially if associated with meta-system ideas or network thinking.

Shifting taxonomic and functional community composition of rivers under land use change

“…Identifying functional thresholds can better inform landscape‐scale conservation actions aimed at improving aquatic biodiversity, including limiting or mitigating land use change or targeting reforestation and instream restoration efforts (Gallagher et al, 2021; Miatta et al, 2021). Our research can help inform a more effective approach to the spatial planning of protected areas by considering additional dimensions of biodiversity (Brumm et al, 2021; Heino et al, 2022). We anticipate that threshold values such as those reported here can support the design of adaptive conservation goals to protect or restore freshwater biodiversity facing continued intensification of land use practices.…”

Controlling for the effects of environmental availability when testing how the environment determines community compositional uniqueness

“…Apart from taxonomic identities, recent studies have also extended ecological uniqueness metrics to spectral, functional trait and phylogenetic data (Heino et al, 2022; Laliberté et al, 2020; Nakamura et al, 2020). Additionally, any β pair metric can be decomposed into species replacement and richness difference components, followed by applying uniqueness metrics to calculate how sites contribute to these components in generating overall β patterns (Legendre, 2014).…”

“…This mechanism, however, is not always considered when assessing uniqueness patterns across space (Schneck et al, 2022). In some cases, the effects of environmental availability can be desirable, such as when the objective is to illustrate or predict the ecological uniqueness of different sites within landscapes and therefore identify conservation priorities (Dansereau et al, 2022; Dubois et al, 2020; Heino et al, 2022). However, if the objective is to examine how environmental drivers affect ecological uniqueness through specific mechanisms, such as whether human disturbance favours generalists and therefore reduces the uniqueness of communities (Allen et al, 2019; Leão et al, 2020), or isolation promotes speciation, and therefore unique communities (Perbiche‐Neves et al, 2019), the effects of environmental availability should be controlled to minimise its confounding effects.…”

Deciphering land‐use influences on boreal lakes to guide landscape planning

“…Moreover, the sites surveyed were ranked into those that most contributed to the overall beta component and, finally, a set of sites that contributed more than 70% of total beta diversity for each feature were suggested to be selected for strict conservation. In this case, the set of sites that embraced more than 70% of beta diversity also harboured more than 90% of species of macrophytes and macroinvertebrates detected during the survey (Heino et al, 2022). This finding suggests that the approach based on site uniqueness may also overcome the problem of including as high as possible gamma diversity in a landscape.…”

“…A way forward to this direction was proposed in a case study on Lake Puruvesi, a large boreal lake, where Heino et al (2022) examined the uniqueness of sites in relation to the other sites sampled. They not only focused on the ecological uniqueness of sites based on taxonomic composition (sensu Legendre & De Cáceres, 2013) of biotic communities but also used a modified approach to calculate the functional uniqueness of biotic communities and the abiotic uniqueness of each site.…”