Inferring the Relative Resilience of Alternative States

Ecological systems may occur in alternative states that differ in ecological structures, functions and processes. Resilience is the measure of disturbance an ecological system can absorb before changing states. However, how the intrinsic structures and processes of systems that characterize their states affects their resilience remains unclear. We analyzed time series of phytoplankton communities at three sites in a floodplain in central Spain to assess the dominant frequencies or "temporal scales" in community dynamics and compared the patterns between a wet and a dry alternative state. The identified frequencies and cross-scale structures are expected to arise from positive feedbacks that…

The importance of phytoplankton production for carbon budgets in a semiarid floodplain wetland

Phytoplankton production (PP) in wetlands is not measured as often as that of macrophytes. A three year-study during a period of sustained high flooding was undertaken in a central Spanish floodplain wetland (Las Tablas de Daimiel National Park) to determine net PP, its spatial heterogeneity and controlling factors, and compare it with primary production in macrophyte communities. This enabled us to estimate carbon budgets for each community. All PP variables showed high spatial and temporal variability among sites, resulting in low coherence even when flooding connected all sites. Net PP corresponded to 25- 36% of submerged plant production and 3-10% of helophyte production. Net PP was con…

We carried out enclosure experiments to assess the potential deleterious effects of the alien species common carp (Cyprinus carpio L.), mosquitofish (Gambusia holbrookii Gir.), and pumpkinseed sunfish (Lepomis gibbosus L.) on water quality and food web in a severely degraded floodplain wetland, the Spanish National Park Las Tablas de Daimiel. With addition of either carp or pumpkinseed sunfish, chlorophyll a and turbidity levels, as well as concentrations of total phosphorus and total nitrogen increased. The magnitude of this increase depended on fish species and was severest in the carp treatment. Mosquitofish did not significantly affect water quality. In the treatments with fish, cyclopo…

Lakes in the era of global change: moving beyond single‐lake thinking in maintaining biodiversity and ecosystem services

The Anthropocene presents formidable threats to freshwater ecosystems. Lakes are especially vulnerable and important at the same time. They cover only a small area worldwide but harbour high levels of biodiversity and contribute disproportionately to ecosystem services. Lakes differ with respect to their general type (e.g. land-locked, drainage, floodplain and large lakes) and position in the landscape (e.g. highland versus lowland lakes), which contribute to the dynamics of these systems. Lakes should be generally viewed as ‘meta-systems’, whereby biodiversity is strongly affected by species dispersal, and ecosystem dynamics are contributed by the flow of matter and substances among locati…