To remotely monitor vegetation at temporal and spatial resolutions unobtainable with satellite-based systems, near remote sensing systems must be employed. To this extent we used Normalized Difference Vegetation Index NDVI sensors and normal digital cameras to monitor the greenness of six different but common and widespread High Arctic plant species/groups (graminoid/Salix polaris; Cassiope tetragona; Luzula spp.; Dryas octopetala/S. polaris; C. tetragona/D. octopetala; graminoid/bryophyte) during an entire growing season in central Svalbard. Of the three greenness indices (2G_RBi, Channel G% and GRVI) derived from digital camera images, only GRVI showed significant correlations with NDVI in all vegetation types. The GRVI (Green-Red Vegetation Index) is calculated as (G_DN − R_DN)/(G_DN + R_DN) where G_DN is Green digital number and R_DN is Red digital number. Both NDVI and GRVI successfully recorded timings of the green-up and plant growth periods and senescence in all six plant species/groups. Some differences in phenology between plant species/groups occurred: the mid-season growing period reached a sharp peak in NDVI and GRVI values where graminoids were present, but a prolonged period of higher values occurred with the other plant species/groups. In particular, plots containing C. tetragona experienced increased NDVI and GRVI values towards the end of the season. NDVI measured with active and passive sensors were strongly correlated (r > 0.70) for the same plant species/groups. Although NDVI recorded by the active sensor was consistently lower than that of the passive sensor for the same plant species/groups, differences were small and likely due to the differing light sources used. Thus, it is evident that GRVI and NDVI measured with active and passive sensors captured similar vegetation attributes of High Arctic plants. Hence, inexpensive digital cameras can be used with passive and active NDVI devices to establish a near remote sensing network for monitoring changing vegetation dynamics in the High Arctic.

To assess the ability of traditional biological recording schemes and lay citizen science approaches to gather data on species distributions and changes therein, we examined bumblebee records from the UK’s national repository (National Biodiversity Network) and from BeeWatch. The two recording approaches revealed similar relative abundances of bumblebee species but different geographical distributions. For the widespread common carder (Bombus pascuorum), traditional recording scheme data were patchy, both spatially and temporally, reflecting active record centre rather than species distribution. Lay citizen science records displayed more extensive geographic coverage, reflecting human population density, thus offering better opportunities to account for recording effort. For the rapidly spreading tree bumblebee (Bombus hypnorum), both recording approaches revealed similar distributions due to a dedicated mapping project which overcame the patchy nature of naturalist records. We recommend, where possible, complementing skilled naturalist recording with lay citizen science programmes to obtain a nation-wide capability, and stress the need for timely uploading of data to the national repository.

Resilience of tundra vegetation to disturbance by herbivores can be low and lead to ecosystem state shifts. Pink-footed geese Anser brachyrhynchus are the most numerous herbivore on Svalbard and disturb vegetation when foraging for below-ground plant biomass (grubbing). We assessed grubbing extent (occurrence of vegetation disturbance) and intensity (proportion of vegetation disturbed) in 2006/07/08 when goose numbers were approximately 56,000 and in 2013 when they increased to approximately 81,000. Despite a 36% increase in population size, in 2013 the grubbing extent at pre-breeding sites was similar to that in 2007/08 but grubbing intensity was lower. Extensive snow cover in 2013 probably dispersed geese over larger areas in search of snow-free patches for feeding, thereby reducing grubbing intensity. At the largest known breeding site, both grubbing extent and intensity increased with more geese. Birds preferentially fed close to nests in previously grubbed wet habitat, probably aiding nest defence and permitting feeding on plants that were easier to remove from the soil. A greater impact on tundra vegetation may occur at nesting areas if the breeding population continues to grow. However, timing of snowmelt appears key in moderating the impact of disturbance on tundra vegetation since it controls spatial distributions of feeding geese.

After the publication of the research paper by Anderson et al. [1], a reanalysis of the data showed that mistakes had been introduced in the calculation of the greenness indices and the filtering for outliers prior to the statistical analysis.