Effects of Long-term Experimental Warming on Aphid Density in the Field

Background and aim Global warming is expected to have large impacts on high alpine and Arctic ecosystems in future. Here we report the effects of 18 years of experimental warming on two contrasting high alpine plant communities in subarctic Sweden.Methods Using open-top chambers (OTCs), we analysed the effects of long-term passive experimental warming on two high alpine plant communities, a species- and nutrient-poor heath and a more nutrient- and species-rich mesic meadow. We determined the impact on species composition, species diversity (at the level of rare, frequent and dominant species in each community), and phylogenetic and functional diversity.Key results Long-term warming drove differentiation in the species composition in both heath and meadow vegetation, with the warmed plots having distinctly different species composition in 2013 compared with 1995. In addition, variability in species composition increased in the meadow, while it decreased in the heath. The long-term warming had a significant negative effect on the three orders of phylogenetic Hill diversity in the meadow. There was a similar tendency in the heath, but only the phylogenetic diversity of dominant species was significantly affected. Long-term warming caused a reduction in graminoids in the heath, while deciduous shrubs increased. In the meadow, cushion-forming plants showed an increase in abundance from 2001 to 2013 in the warmed plots. Conclusions Responses in species and phylogenetic diversity to experimental warming varied over both time (medium vs long-term responses) and space (i.e. between the two neighbouring plant communities heath and meadow). The meadow community was more negatively affected in terms of species and phylogenetic diversity than the heath community. A potential driver for the changes in the meadow may be decreased soil moisture caused by the long-term warming.

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Examination of long-term suppression of aphid density through augmentative release of larvae of flightless Harmonia axyridis (Coleoptera: Coccinellidae) and adults of Aphidius colemani (Hymenoptera: Aphidiinae) onto eggplants in commercial greenhouse, with a combination of sweet alyssum intercropping and brine-shrimp egg provision

Annual Report of The Kansai Plant Protection Society ◽

10.4165/kapps.60.55 ◽

2018 ◽

Vol 60 (0) ◽

pp. 55-59

Author(s):

Shuji Kaneko ◽

Kanako Shirotsuka ◽

Manabu Shibao

Keyword(s):

Brine Shrimp ◽

Harmonia Axyridis ◽

Aphidius Colemani ◽

Aphid Density ◽

Augmentative Release

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Bryophyte cover and richness decline after 18 years of experimental warming in Alpine Sweden

10.32942/osf.io/zrbqf ◽

2019 ◽

Author(s):

Juha Alatalo ◽

Annika Jägerbrand ◽

Mohammad Bagher Erfanian ◽

Shengbin Chen ◽

Shou-Qin Sun ◽

...

Keyword(s):

Climate Change ◽

Negative Impact ◽

Species Abundance ◽

Experimental Warming ◽

Litter Cover ◽

General Decline ◽

Principal Response Curve ◽

Heath Community ◽

Abundance And Diversity

Background and Aims: Climate change is expected to affect alpine and Arctic tundra communities. Most previous long-term studies have focused on impacts on vascular plants, but this study examined potential impacts of long-term warming on bryophyte communities.Methods: Experimental warming with open-top chambers (OTCs) was applied for 18 years to a mesic meadow and a dry heath alpine plant community. Species abundance was measured in 1995, 1999, 2001 and 2013. Key results: Species composition changed significantly from the original communities in the heath, but remained similar in the mesic meadow. Experimental warming increased beta diversity in the heath community. Bryophyte cover and species richness both declined with long-term warming, while Simpson diversity showed no significant responses. Over the 18-year period, bryophyte cover in warmed plots decreased from 43% to 11% in heath and from 68% to 35% in meadow (75% and 48% decline, respectively, in original cover), while richness declined by 39% and 26%, respectively. The decline in both cover and richness first emerged after seven years. Warming caused a significant increase in litter in both plant communities. Litter cover had a negative impact on bryophyte cover in both communities. Conclusions: This study showed that bryophyte species do not all respond similarly to climate change. Total bryophyte cover declined in both dry heath and mesic meadow communities under experimental long-term warming (by 1.5-3°C), driven by general declines in many species. Principal response curve, cover and richness results suggested that bryophytes in alpine heath vegetation are more susceptible to warming than those in meadow vegetation, supporting the suggestion that bryophyte communities may be less resistant in drier environments than in wetter habitats. Species loss was slower than the general decline in bryophyte abundance, and diversity remained similar in both communities. Increased litter cover led to a steep decline in bryophyte cover.

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