Effectiveness of eradication measures for the invasive Australian swamp stonecrop Crassula helmsii

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The Ecosystem Resilience Approach (ERA) to control the invasive Australian swamp stonecrop (Crassula helmsii)

The invasive Australian swamp stonecrop (Crassula helmsii) threatens species characteristic of shallow soft water lakes and pools in Europe. Eradication of this plant is, however, difficult and costly once a large population has established. For this reason, we here explore a novel ecosystem resilience approach (ERA) to control this species. These datasets contain information about the first field performances of the ERA. Effectiveness of the ERA is measured by determining the cover (%) of the invasive species and the introduced and naturally established native vegetation after the introduction of a competing species in field plots. Additionally we’ve observed and measured field characteristics (soil- and water nutrient content by AA- and ICP analysis) to describe difference between the treated locations. *The data appropriate to this article may contain Dutch notes. For an English explanation, please contact the author of the data Abstract of paper: The invasive Australian swamp stonecrop (Crassula helmsii) threatens species characteristic of shallow soft water lakes and pools in Europe. Anthropogenic disturbances of these ecosystems cause open niches in their littoral zones and allow C. helmsii to form dominant stands, especially under nutrient enrichment. Eradication of this amphibious and clonal plant is, however, difficult and costly once a large population has established. For this reason, we here explore a novel ecosystem resilience approach (ERA) to control this species. This approach includes supressing the species by facilitating the occurrence and expansion of native vegetation. This requires a set-back of C. helmsii’s abundance by actively reducing its biomass, and the rehabilitation of optimal environmental conditions for native species. Our ERA study in four nature areas shows that restoring abiotic conditions, a one-time reduction of C. helmsii’s biomass and the introduction of native species makes the ecosystem more resilient against invasions, as shown by less recolonization of this invasive plant species. Therefore, we state that ERA can effectively be applied in practice to decrease the invasibility of ecosystems by C. helmsii. Effectiveness, costs and benefits, and recommendations for application in practice are discussed. Overall, we argue that incorporating ERA in nature- and water management will provide more sustainable solutions in terms of biodiversity as well as economics for invasive species prevention and control

Invasive Australian swamp stonecrop (Crassula helmsii) negatively affects spawning but accelerates larval growth of the endangered natterjack toad (Epidalea calamita)

C. helmsii often invades the breeding habitat of endangered amphibians, such as Epidalea calamita. However, effects on natterjack population were unclear. The spawning rate, egg survival and the speed of larval growth of this toad species in relation to the presence of C. helmsii were studied. For this study we’ve measured temperature (by temperature data loggers) and chemical properties (by ICP- and AA analysis) of the water, as affected by C. helmsii. Additionally we’ve measured numbers of spawning, egg survival and larval sizes to investigate larval growth rate performing an exclosure experiment at a field location (Gijzenrooise zegge). *The data appropriate to this article may contain Dutch notes. For an English explanation, please contact the author of the data Abstract of the paper: The invasive Crassula helmsii is expanding in Europe. Several ecological effects are described, most of which focus on ecosystem functioning and native vegetation but rarely on fauna. In North-western Europe, C. helmsii often invades the breeding habitat of endangered amphibians, such as Epidalea calamita. The spawning rate, egg survival and the speed of larval growth of this toad species in relation to the presence of C. helmsii were studied. In order to unravel causal mechanisms, the outcome is related to temperature and chemical properties of the water, as affected by C. helmsii. Spawning and egg survival were significantly lower in case of C. helmsii dominance compared to bare soil conditions, and negatively affected the population size of E. calamita. However, larval growth rate was significantly higher in C. helmsii dominated treatments, which could be beneficial for tadpoles. Differences in water temperature and chemistry were a possible explanation for these effects. It remains unclear whether the population viability of E. calamita is negatively affected when C. helmsii is present. In many areas, however, this plant species completely overgrows and causes desiccation of waterbodies. Therefore, appropriate management measures will be required to protect this toad against this invader

The Ecosystem Resilience Approach (ERA) to control the invasive Australian swamp stonecrop (Crassula helmsii): Innovative control of C. helmsii

The invasive Australian swamp stonecrop (Crassula helmsii) threatens species characteristic of shallow soft water lakes and pools in Europe. Eradication of this plant is, however, difficult and costly once a large population has established. For this reason, we here explore a novel ecosystem resilience approach (ERA) to control this species. These datasets contain information about the first field performances of the ERA. Effectiveness of the ERA is measured by determining the cover (%) of the invasive species and the introduced and naturally established native vegetation after the introduction of a competing species in field plots. Additionally we’ve observed and measured field characteristics (soil- and water nutrient content by AA- and ICP analysis) to describe difference between the treated locations. *The data appropriate to this article may contain Dutch notes. For an English explanation, please contact the author of the data Abstract of paper: The invasive Australian swamp stonecrop (Crassula helmsii) threatens species characteristic of shallow soft water lakes and pools in Europe. Anthropogenic disturbances of these ecosystems cause open niches in their littoral zones and allow C. helmsii to form dominant stands, especially under nutrient enrichment. Eradication of this amphibious and clonal plant is, however, difficult and costly once a large population has established. For this reason, we here explore a novel ecosystem resilience approach (ERA) to control this species. This approach includes supressing the species by facilitating the occurrence and expansion of native vegetation. This requires a set-back of C. helmsii’s abundance by actively reducing its biomass, and the rehabilitation of optimal environmental conditions for native species. Our ERA study in four nature areas shows that restoring abiotic conditions, a one-time reduction of C. helmsii’s biomass and the introduction of native species makes the ecosystem more resilient against invasions, as shown by less recolonization of this invasive plant species. Therefore, we state that ERA can effectively be applied in practice to decrease the invasibility of ecosystems by C. helmsii. Effectiveness, costs and benefits, and recommendations for application in practice are discussed. Overall, we argue that incorporating ERA in nature- and water management will provide more sustainable solutions in terms of biodiversity as well as economics for invasive species prevention and control