scholarly journals Functional Role of Extrafloral Nectar in Boreal Forest Ecosystems under Climate Change

Forests ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 67 ◽  
Author(s):  
Jarmo Holopainen ◽  
James Blande ◽  
Jouni Sorvari

Carbohydrate-rich extrafloral nectar (EFN) is produced in nectaries on the leaves, stipules, and stems of plants and provides a significant energy source for ants and other plant mutualists outside of the flowering period. Our review of literature on EFN indicates that only a few forest plant species in cool boreal environments bear EFN-producing nectaries and that EFN production in many boreal and subarctic plant species is poorly studied. Boreal forest, the world’s largest land biome, is dominated by coniferous trees, which, like most gymnosperms, do not produce EFN. Notably, common deciduous tree species that can be dominant in boreal forest stands, such as Betula and Alnus species, do not produce EFN, while Prunus and Populus species are the most important EFN-producing tree species. EFN together with aphid honeydew is known to play a main role in shaping ant communities. Ants are considered to be keystone species in mixed and conifer-dominated boreal and mountain forests because they transfer a significant amount of carbon from the canopy to the soil. Our review suggests that in boreal forests aphid honeydew is a more important carbohydrate source for ants than in many warmer ecosystems and that EFN-bearing plant species might not have a competitive advantage against herbivores. However, this hypothesis needs to be tested in the future. Warming of northern ecosystems under climate change might drastically promote the invasion of many EFN-producing plants and the associated insect species that consume EFN as their major carbohydrate source. This may result in substantial changes in the diet preferences of ant communities, the preventative roles of ants against insect pest outbreaks, and the ecosystem services they provide. However, wood ants have adapted to using tree sap that leaks from bark cracks in spring, which may mitigate the effects of improved EFN availability.

2012 ◽  
Vol 367 (1605) ◽  
pp. 2955-2961 ◽  
Author(s):  
Lee E. Frelich ◽  
Rolf O. Peterson ◽  
Martin Dovčiak ◽  
Peter B. Reich ◽  
John A. Vucetich ◽  
...  

As the climate warms, boreal tree species are expected to be gradually replaced by temperate species within the southern boreal forest. Warming will be accompanied by changes in above- and below-ground consumers: large moose ( Alces alces ) replaced by smaller deer ( Odocoileus virginianus ) above-ground, and small detritivores replaced by larger exotic earthworms below-ground. These shifts may induce a cascade of ecological impacts across trophic levels that could alter the boreal to temperate forest transition. Deer are more likely to browse saplings of temperate tree species, and European earthworms favour seedlings of boreal tree species more than temperate species, potentially hindering the ability of temperate tree species to expand northwards. We hypothesize that warming-induced changes in consumers will lead to novel plant communities by changing the filter on plant species success, and that above- and below-ground cascades of trophic interactions will allow boreal tree species to persist during early phases of warming, leading to an abrupt change at a later time. The synthesis of evidence suggests that consumers can modify the climate change-induced transition of ecosystems.


2010 ◽  
Vol 86 (3) ◽  
pp. 312-316 ◽  
Author(s):  
Yueh-Hsin Lo ◽  
Juan A. Blanco ◽  
J. P. (Hamish) Kimmins

In this note we raise our concerns about the use of climate envelope models as a basis for forest planning under climate change. Such models assume constant relationships among tree species presence, abundance or growth rates and climatic variables, and that these can be transferred from their current distribution areas to areas that are predicted to have a similar future climate. Climate is an important determinant of tree species distributions, but its effects are mediated through soils, competition from other plant species, herbivores, diseases, insects and fire. This complexity should be addressed when making predictions about plant species distribution changes. If forecasts based only on climate are accepted uncritically and become the basis for forest policy and practice, there could be important consequences for the success of forest management. We illustrate the issue with the historical response of tree growth to climate variability for three conifer species along an altitudinal gradient in southern interior British Columbia. The growth–climate relationships differ not only among species but also between ecological zones, which implies that the different combinations of tree species and site will react differently to the same change in climate. All things considered, caution is needed when developing management plans using predicted future tree distributions based only on current/past tree/climate relationships. Key words: climate-envelope models, climate change, species distributions, dendroclimatology


Ecology ◽  
2010 ◽  
Vol 91 (3) ◽  
pp. 767-781 ◽  
Author(s):  
Paul Kardol ◽  
Melissa A. Cregger ◽  
Courtney E. Campany ◽  
Aimee T. Classen

Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1047
Author(s):  
Gianni Bellocchi ◽  
Catherine Picon-Cochard

Associated with livestock farming, grasslands with a high diversity of plant species are at the core of low-input fodder production worldwide [...]


2021 ◽  
Author(s):  
Birgit Nordt ◽  
Isabell Hensen ◽  
Solveig Franziska Bucher ◽  
Martin Freiberg ◽  
Richard B. Primack ◽  
...  

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