Abstracts

Presented by Robert Clark - Email: bob.clark@canada.ca

Wetlands are being lost or degraded, threatening biodiversity to an extent greater than in most ecosystems. To develop science-supported responses, we require an understanding of interacting effects of land-use and climate change on wetland biodiversity. We evaluated how current climate, climate change and land-use (conversion of grassland to cropland, loss of natural habitats), and wetland-water quality affect aquatic macroinvertebrates and birds at sites in Alberta, Canada. Macroinvertebrate taxa richness (MTR) was negatively related to salinity, whereas total precipitation and total phosphorous negatively influenced chironomids and odonates, respectively. Abundances of chironomids were positively associated with cropland cover. Greater area of non-woody riparian vegetation reduced the negative effect of salinity on MTR. Higher cropland cover and dissolved organic carbon synergistically interacted with total precipitation to affect chironomids. Higher grassland cover also increased the negative impact of total phosphorous on odonates. Higher average rainfall and greater warming temperatures over time were key determinants of higher bird species richness (BSR) and abundances of several bird functional groups. Area of pasture and forages, shrubland, grassland, trees, and wetlands were positively associated with most bird groups and BSR. Warming temperatures over time ameliorated the negative effects of higher cropland or less shrubland on aerial insectivores, arboreal herbivores, arboreal insectivores, terrestrial herbivores, and terrestrial insectivores. Climate patterns and climate change were as important as local land-use pressures for biodiversity with stronger impacts on birds. Climate change as a ghost of the past was more influential than current climate and provided novel empirical evidence that progressively warmer, wetter conditions is benefiting some bird groups, including aerial insectivores, a group of conservation concern. Riparian vegetation ameliorated the negative impacts of climate and water quality gradients on MTR and could mitigate the consequences of global change in intensive agricultural systems.