Connecting Top-Down and Bottom-Up Approaches in Environmental Observing.

Effective responses to rapid environmental change rely on observations to inform planning and decision-making. Reviewing literature from 124 programs across the globe and analyzing survey data for 30 Arctic community-based monitoring programs, we compare top-down, large-scale program driven approaches with bottom-up approaches initiated and steered at the community level. Connecting these two approaches and linking to Indigenous and local knowledge yields benefits including improved information products and enhanced observing program efficiency and sustainability. We identify core principles central to such improved links: matching observing program aims, scales, and ability to act on information; matching observing program and community priorities; fostering compatibility in observing methodology and data management; respect of Indigenous intellectual property rights and the implementation of free, prior, and informed consent; creating sufficient organizational support structures; and ensuring sustained community members' commitment. Interventions to overcome challenges in adhering to these principles are discussed.

Non-native vascular flora of the Arctic: Taxonomic richness, distribution and pathways.

We present a comprehensive list of non-native vascular plants known from the Arctic, explore their geographic distribution, analyze the extent of naturalization and invasion among 23 subregions of the Arctic, and examine pathways of introductions. The presence of 341 non-native taxa in the Arctic was confirmed, of which 188 are naturalized in at least one of the 23 regions. A small number of taxa (11) are considered invasive; these plants are known from just three regions. In several Arctic regions there are no naturalized non-native taxa recorded and the majority of Arctic regions have a low number of naturalized taxa. Analyses of the non-native vascular plant flora identified two main biogeographic clusters within the Arctic: American and Asiatic. Among all pathways, seed contamination and transport by vehicles have contributed the most to non-native plant introduction in the Arctic.

Resilience and Adaptation: Yukon River Watershed Contaminant Risk Indicators.

River watersheds are among the most complex terrestrial features in Alaska, performing valuable ecosystem functions and providing services for human society. Rivers are vital to both estuarine and aquatic biota and play important roles in biogeochemical cycles and physical processes. The functions of watersheds have been used as vulnerability indicators for ecosystem and socioeconomic resilience. Despite a long history of human activity, the Yukon River has not received the holistic and interdisciplinary attention given to the other great American river systems. By using hypothesis-based monitoring of key watershed functions, we can gain insight to regime-shifting stresses such as fire, toxins, and invasive species development. Coupling adaptive risk management practices involving stakeholders with place-based education, especially contaminants and nutrition related, can maintain resilience within communities. The Yukon watershed provides a broadscale opportunity for communities to monitor the environment, manage resources, and contribute to stewardship policy formation. Monitoring keystone species and community activities, such as citizen science, are critical first steps to following changes to resiliency throughout the Yukon watershed. Creating a policy environment that encourages local experimentation and innovation contributes to resilience maintenance during development-imposed stress.

Effects of non-native Melilotus albus on pollination and reproduction in two boreal shrubs.

The establishment of abundantly flowered, highly rewarding non-native plant species is expected to have strong consequences for native plants through altered pollination services, particularly in boreal forest where the flowering season is short and the pollinator pool is small. In 18 boreal forest sites, we added flowering Melilotus albus to some sites and left some sites as controls in 2 different years to test if the invasive plant influences the pollination and reproductive success of two co-flowering ericaceous species: Vaccinium vitis-idaea and Rhododendron groenlandicum. We found that M. albus increased the pollinator diversity and tended to increase visitation rates to the focal native plant species compared to control sites. Melilotus albus facilitated greater seed production per berry in V. vitis-idaea when we added 120 plants compared to when we added 40 plants or in control sites. In R. groenlandicum, increasing numbers of M. albus inflorescences lowered conspecific pollen loads and percentage of flowers pollinated; however, no differences in fruit set were detected. The number of M. albus inflorescences had greater importance in explaining R. groenlandicum pollination compared to other environmental variables such as weather and number of native flowers, and had greater importance in lower quality black spruce sites than in mixed deciduous and white spruce sites for explaining the percentage of V. vitis-idaea flowers pollinated. Our data suggest that the identity of new pollinators attracted to the invaded sites, degree of shared pollinators between invasive and native species, and variation in resource limitation among sites are likely determining factors in the reproductive responses of boreal native plants in the presence of an invasive.