FunDivEUROPE Knowledge Transfer Platform - Soil
http://www.fundiveurope.eu/taxonomy/term/325
enThe understorey, a forest layer with an underestimated importance for ecosystem functioning
http://www.fundiveurope.eu/node/221
<div class="field field-name-field-intended-reader field-type-list-text field-label-inline clearfix"><div class="field-label">Intended Reader: </div><div class="field-items"><div class="field-item even">Researcher</div></div></div><div class="field field-name-field-image field-type-image field-label-hidden"><div class="field-items"><div class="field-item even"><img typeof="foaf:Image" src="http://www.fundiveurope.eu/sites/default/files/birch_web_0.jpg" width="300" height="225" alt="" /></div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even" property="content:encoded"><p>The major forest types in Europe, from the Boreal to the Mediterranean region, all include a variable number of native vascular plant species in the understorey layer (1.3 m height), both herbaceous and woody. In spite of its small stature and biomass this layer can contain 90% or more of the plant species of the forest. The functional role of the understory vegetation has already been shown in previous studies on temperate forests. They can serve as:</p>
<ul><li>Food plants – Several understorey species produce berries or vegetative parts that represent an important and/or popular food for local people. Examples are the bluberries (Vaccinium myrtillus) and other dwarf Ericaceae growing diffusely in the boreal forests, or the wild Asparagus in the thermophilous deciduous forests of southern Europe.</li>
<li>Medicinal plants – Some species are known in the local traditional medecine for their therapeutic properties</li>
<li>Ornamentals – Several understorey species are used as ornamentals Cyclamen or are wild relatives of cultivated varieties Viola Helleborus.</li>
<li>Understorey species may also be involved in Carbon fixation and sequestration: The understorey contributes significantly to carbon sequestration, and can account for up to 5% of the net primary production of the forest.</li>
<li>Source of nectar for pollinators and seeds/fruits for small mammals. Many species produces nectar-rich flowers that provide source of energy to a wide range of pollinators and seeds or fruits that serve as food for forest animals. An example are the seeds of species such as Viola that have a lipid-rich elaiosome for dispersal by ants.</li>
<li>Decomposition and nutrient cycling. The herb layer contribute to up 15% of the foliar litter to the forest floor. Understorey litter has usually an elevated concentration of nutrients compared to trees (especially N and K). The rapid decomposition and high turnover rate of the herb-layer facilitates efficient recycling of nutrients in the forest soil.</li>
<li>Tree regeneration. Understorey species may facilitate regeneration of tree species by positively influencing microclimatic conditions at the ground level and by sheltering (hiding) the seedlings against browsing by herbivores.</li>
<li>Mechanisms of resistance to invasion by alien organisms. Understorey vegetation often includes highly adapted and competitive species that are likely to reduce the chances for alien, exotic species to establish in the community and become invaders.</li>
<li>Habitat provision for a multitude of small mammals and insects.</li>
</ul><p><img alt="" src="/sites/default/files/DSCN0996_0.JPG" style="height:227px; width:303px" />Establishing universal priorities among these services is very difficult, as the relative importance of each of them is strongly context-dependent. First, the region and type of ecosystem determines the pool of understorey species present, and the services provided are mostly species-specific. Secondly, the cultural and historical local contexts vary to the same extent as the type of forest ecosystem, so that a species that is not associated to a service in a given region may be considered of high interest in another region. Moreover, Hector & Bagchi (2007) and Isbell et al. (2011) indicated that different species promote different functions in different years, at different locations and under different environmental conditions. This promotes the precautionary principle of conserving maximum biodiversity in order to obtain long-term forest ecosystem stability and provisioning of ecosystem services. Trees have a species-specific impact on local environmental conditions: the mean amount, variability and nature of the light reaching the forest floor (Messier et al. 1998), soil water content via differences in throughfall, transpiration and water uptake by roots (e.g. Barbier et al. 2008, 2009; Geiβler et al. 2012), soil, nutrient availability and acidity via differences in litter quality and quantity, nitrogen fixation, nutrient uptake and atmospheric deposition on leaves and needles (e.g. Augusto et al. 2003; Hagen-Thorn et al. 2004), phytotoxic compounds, thickness litter layer (Rodríguez-Calcerrada et al. 2011). As a consequence of these tree species identity effects, the composition of the tree layer may substantially affect herb layer composition and productivity as the germination and performance of herb layer species depends on the environmental conditions (e.g. Ellenberg & Leuschner 2010).</p>
<p><!--[if gte mso 9]><p><xml><br />
The overall impact of tree species richness<br />
on herb layer diversity, productivity and therefore also nutrient stocks, can<br />
be composed of additive and non-additive effects. In case it results solely<br />
from identity effects of the component tree species on the environmental<br />
conditions, the impact of tree species richness is purely additive and can be<br />
derived from the (binary) presence/absence of individual tree species. In<br />
forests composed of multiple tree species, this results in a diverse,<br />
patch-scale pattern of environmental conditions (Yankelevich et al. 2006; Morin<br />
et al. 2011). According to the environmental heterogeneity hypothesis (Ricklefs<br />
1977; Huston 1979), a heterogeneous environmental pattern may lead to higher<br />
forest-level herb layer diversity (Reich et al. 2012), as a result of<br />
compositional dissimilarities between the patches, even though there may be no<br />
differences in herb layer species richness between the patches. It may also<br />
lead to higher forest-level productivity as herb layer species are more likely<br />
to find optimal growth conditions in variable environments (Vockenhuber et al.<br />
2011). Non-additive effects of tree species richness on the herb layer may appear<br />
as a result of complementary resource use between herb layer species or<br />
interactions between tree species. For example, the mix of litter in stands<br />
with multiple tree species may induce complementarity in belowground resource<br />
uptake, e.g. use of different forms of the same nutrient or complementary<br />
rooting volumes (Sapijanskas et al. 2013). Interactions between tree species<br />
may induce novel environmental conditions. Ball et al. (2008) found that the<br />
mixing of litter in stands with multiple tree species may induce non-additive<br />
effects on litter N content, while the results of Dijkstra et al. (2009)<br />
indicated a non-additive effect on soil C respiration and net N mineralization.<br />
Decomposition rates in litter mixtures may also differ from the predictions<br />
based on single species (Wu et al. 2013), leading to differences in nutrient<br />
availability and soil acidity. This novel environment may induce the loss of<br />
specific herb layer species compared to the component monocultures, in case the<br />
new environmental conditions do not match their niche requirements anymore, and<br />
bring along opportunities for species that were not yet present in the<br />
component monocultures. In this case, the impact of tree layer diversity on herb<br />
layer diversity and productivity may be positive, neutral or even negative. We<br />
expect the ratio between additive (resource heterogeneity) and non-additive<br />
(novel environment) effects of tree species richness on the environmental<br />
conditions to depend on the mixing intensity. The more intimately tree species<br />
are mixed, the stronger the interspecific interactions and the more<br />
non-additive effects will dominate. --></p>
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<div class="video-embed-description">Kris Verheyen - tree species and understorey vegetation</div></div></div></div><div class="field field-name-field-hypothesis-reference field-type-entityreference field-label-above"><div class="field-label">Hypothesis Reference: </div><div class="field-items"><div class="field-item even"><a href="/node/27">Diversity and abundance of the understorey vegetation increases with increasing overstorey diversity in the canopy</a></div></div></div><div class="field field-name-field-biblio-reference field-type-entityreference field-label-above"><div class="field-label">Reference: </div><div class="field-items"><div class="field-item even"><a href="/node/168">The ecological significance of the herbaceous layer in temperate forest ecosystems</a></div></div></div><div class="field field-name-field-location field-type-entityreference field-label-above"><div class="field-label">Location: </div><div class="field-items"><div class="field-item even"><a href="/node/6">Europe</a></div></div></div><div class="field field-name-field-biblio-further-readings field-type-entityreference field-label-above"><div class="field-label">Further Readings: </div><div class="field-items"><div class="field-item even"><a href="/node/108">Temporal changes in forest plant communities at different site types</a></div><div class="field-item odd"><a href="/node/147">Understorey vegetation shifts following the conversion of temperate deciduous forest to spruce plantation</a></div><div class="field-item even"><a href="/node/88">Dynamics of understorey herbaceous plant diversity following shrub clearing of cork oak forests: A five-year study</a></div><div class="field-item odd"><a href="/node/110">Driving factors behind the eutrophication signal in understorey plant communities of deciduous temperate forests</a></div><div class="field-item even"><a href="/node/154">Unexpected understorey community development after 30 years in ancient and post-agricultural forests</a></div></div></div><div class="field field-name-field-question-reference field-type-entityreference field-label-above"><div class="field-label">Question Reference: </div><div class="field-items"><div class="field-item even"><a href="/node/48">Is understorey vegetation diversity associated with tree species diversity in European forests?</a></div><div class="field-item odd"><a href="/node/181">Why is biodiversity important?</a></div></div></div><div class="field field-name-field-tags field-type-taxonomy-term-reference field-label-above clearfix"><h3 class="field-label">Tags: </h3><ul class="links"><li class="taxonomy-term-reference-0"><a href="/taxonomy/term/308" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Tree species traits</a></li><li class="taxonomy-term-reference-1"><a href="/taxonomy/term/325" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Soil</a></li><li class="taxonomy-term-reference-2"><a href="/taxonomy/term/286" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Conditions</a></li><li class="taxonomy-term-reference-3"><a href="/taxonomy/term/17" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Understorey Vegetation</a></li><li class="taxonomy-term-reference-4"><a href="/taxonomy/term/36" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Litter</a></li><li class="taxonomy-term-reference-5"><a href="/taxonomy/term/29" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">seed</a></li><li class="taxonomy-term-reference-6"><a href="/taxonomy/term/301" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Biodiversity</a></li><li class="taxonomy-term-reference-7"><a href="/taxonomy/term/58" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Nutrient availability</a></li><li class="taxonomy-term-reference-8"><a href="/taxonomy/term/855" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Food</a></li><li class="taxonomy-term-reference-9"><a href="/taxonomy/term/34" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Root</a></li><li class="taxonomy-term-reference-10"><a href="/taxonomy/term/122" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Plant</a></li><li class="taxonomy-term-reference-11"><a href="/taxonomy/term/853" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Primary production</a></li><li class="taxonomy-term-reference-12"><a href="/taxonomy/term/48" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Tree species neighbourhood</a></li><li class="taxonomy-term-reference-13"><a href="/taxonomy/term/40" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Nutrient cycling</a></li><li class="taxonomy-term-reference-14"><a href="/taxonomy/term/129" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Soil water content</a></li><li class="taxonomy-term-reference-15"><a href="/taxonomy/term/30" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Resistance</a></li><li class="taxonomy-term-reference-16"><a href="/taxonomy/term/856" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Organisms</a></li></ul></div><div class="field field-name-field-userrating field-type-fivestar field-label-inline clearfix"><div class="field-label">Userrating: </div><div class="field-items"><div class="field-item even"><div class="clearfix fivestar-average-stars fivestar-average-text"><div class="fivestar-static-item"><div class="form-item form-type-item">
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</ul>Wed, 09 Apr 2014 11:04:26 +0000E.Ampoorter221 at http://www.fundiveurope.euhttp://www.fundiveurope.eu/node/221#commentsEffect of nitrogen deposition reduction on biodiversity and carbon sequestration
http://www.fundiveurope.eu/node/188
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</ul>Fri, 27 Dec 2013 12:32:19 +0000W.De Vries188 at http://www.fundiveurope.euhttp://www.fundiveurope.eu/node/188#commentsError | FunDivEUROPE Knowledge Transfer Platform