Wetland Biodiversity and Ecosystem Conservation: Integrating Genetic, Species, and Ecosystem Perspectives for Effective Action

Wetlands are among the most productive yet most rapidly degrading ecosystems on Earth [1,2,3]. Covering only 5–8% of the land surface, they store ~30% of terrestrial soil carbon and support 40% of global biodiversity [4,5]. The provision of essential services, from water purification and flood control to carbon sequestration and climate resilience, depends on maintaining intact biodiversity across multiple levels of organisation [6,7]. However, conservation efforts have often focused on single species or simple area targets, neglecting the complex, multi-scale interactions that sustain wetland functions. Effective wetland conservation must simultaneously address genetic and population viability, species-level stressors, ecosystem-level cascades, and innovative restoration approaches [8]. This Special Issue highlights key emerging insights and outlines priority directions for science and action.

At the genetic and population level, a growing body of evidence indicates that habitat diversity and environmental gradients are as important as standing genetic variation in sustaining functional diversity and population resilience [9,10,11,12]. For the widespread wetland grass Phragmites australis, common garden experiments across eastern China show that phenotypic plasticity, rather than genetic variation alone, drives growth and decomposition [9]. For the Yangtze finless porpoise in Poyang Lake, population viability analysis projects a >90% decline in genetic diversity over the last 100 years and an extinction probability of 0.241 under baseline scenarios, despite recent population increases [10]. Key parameters, including breeding rate, sex ratio at birth, and gene flow, underscore the importance of connectivity and demographic management. Together, these studies demonstrate that environmental conditions and genetic diversity are interdependent: environmental heterogeneity shapes the expression of genetic potential, while genetic diversity provides the raw material for long-term adaptation [13].

At the species level, anthropogenic stressors such as microplastic pollution [14,15] and human land-use intensification [1,16] profoundly alter wetland plant and animal communities. Microplastic types exert type-specific and concentration-dependent effects on the native sedge Scirpus mariqueter: PET and PE suppress belowground biomass by more than 40% even at 0.1% concentration, whereas PP can increase seed production [15]. Such differential responses indicate that risk assessments must move beyond total microplastic mass to polymer identity. Human activities further shape species assemblages: intensive aquaculture and floating photovoltaic systems on coal mining subsidence wetlands reduce waterbird diversity and eliminate threatened species, whereas ecologically managed or unutilised subsidence wetlands can serve as valuable alternative habitats [16]. Citizen science platforms such as iNaturalist are increasingly valuable for tracking wetland species distributions and phenology on a large scale, complementing targeted research [17]. These examples collectively show that species-level conservation requires explicit consideration of pollutant chemistry and the intensity of human use.

At the ecosystem level, cascading effects link hydrology, plant nutrition, animal communities, and ecosystem services [6,7,18]. A systematic review of 76 studies finds that biodiversity monitoring in constructed wetlands remains heavily biased towards microbial communities using generic indices (e.g., Shannon–Wiener, Chao1), while plants and animals are rarely linked to treatment performance or ecosystem services [19]. This gap calls for standardised, trait-based and phylogenetically informed frameworks (e.g., Rao’s quadratic entropy, Faith’s phylogenetic diversity) that directly connect biodiversity to functions such as nutrient removal and carbon sequestration. Recognising and measuring these ecosystem-level interactions is a prerequisite for moving beyond static inventories to dynamic functional assessments.

Turning to restoration and management practices, the reviewed studies offer concrete lessons for improving conservation outcomes. For coal mining subsidence wetlands, long-term waterbird surveys demonstrate that “ecological aquaculture” and unutilised areas provide far greater conservation value than intensive development, suggesting that management regimes are a powerful lever even in heavily modified landscapes [16]. Such areas exemplify Other Effective area-based Conservation Measures (OECMs)—sites outside formal protected areas that deliver long-term in situ biodiversity conservation [20]. For threatened species, comprehensive protection combining total fishing bans, individual rescue, and population interchange reduces extinction probability from 0.241 to 0.0028 in the Yangtze finless porpoise, proving that aggressive action works [10]. The key message is that wetland restoration must shift from a narrow focus on area-based targets to a broader portfolio of active, context-specific, and multi-objective management strategies.

In conclusion, the science of wetland biodiversity conservation is moving decisively towards integration across genetic, species, and ecosystem levels. Building on the insights from this Special Issue, future research should prioritise three frontiers. First, explore the origin and evolution of key functional traits and biotic interactions in wetland organisms, from phenotypic plasticity to trophic cascades [21,22]. Second, predict the responses and adaptation of wetland biodiversity to future global change, including climate warming, microplastic pollution, and land-use intensification [23,24]. Third, develop synergistic mechanisms that couple wetland ecological conservation and restoration with regional socioeconomic development [25,26]. Achieving such synergy requires not only advancing academia, government, business, and the millions of people whose livelihoods depend on wetlands [27], but also harnessing citizen science for large-scale biodiversity monitoring [17] and formally integrating OECMs into national and corporate conservation strategies [20].

The window for action is narrowing, but the tools and insights now available, from population viability modelling to adaptive management, offer a realistic pathway to bend the curve of wetland loss. It is time to move beyond description to implementation by embedding genetic, species, and ecosystem perspectives into national biodiversity strategies, corporate environmental reporting, and on-ground restoration projects. Only then can wetlands fulfil their role as life-support infrastructure for both people and nature.