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Population Size of Common Species (Z8)
 
The Z8 indicator “Population Size of Common Species” is designed to reveal long-time changes in the populations of common animal and plant species. Characterized by large populations and wide distributions, common species are of great ecological importance: They make up the major share of the living biomass, they supply an abundant food resource for other organisms, they provide the largest contribution to ecosystem services, and they help shape the appearance not only of their habitats, but also of landscapes as whole.
 
 
Changes in the distributions of breeding bird, plant and moss species
 

The table below lists the ten bird, plant and moss species whose nationwide distributions have increased or declined most during the 2001-2009 surveying period (significant changes in frequency only). Species occurring in under 3% of inspected sampling areas have been disregarded.

Breeding birds   Plants   Mosses  
Common Crossbill abnehmender Trend Colonial Bentgrass abnehmender Trend Drepanocladus uncinatus zunehmender Trend
Garden Warbler abnehmender Trend Early Dog-Violet* zunehmender Trend Dicranum montanum zunehmender Trend
Bullfinch abnehmender Trend Dandelion* zunehmender Trend Hypnum cupressiforme zunehmender Trend
Common Swift zunehmender Trend Red Clover zunehmender Trend Velutina De Not. section* zunehmender Trend
Ring Ouzel abnehmender Trend Sweet Vernalgrass* zunehmender Trend Eurhynchium hians* zunehmender Trend
Wood Pigeon zunehmender Trend Red Fescue zunehmender Trend Bryum capillare* zunehmender Trend
Red Kite zunehmender Trend Rough Bluegrass zunehmender Trend Radula complanata zunehmender Trend
Fieldfare abnehmender Trend Common Ash zunehmender Trend Plicata Kindb. section* zunehmender Trend
    Bugleweed zunehmender Trend Fissidens taxifolius zunehmender Trend
    European Mountain Ash zunehmender Trend Plagiomnium affine* zunehmender Trend
* Aggregates and complexes

Comments:

• The large majority of breeding bird species underwent no significant change in distribution. Among the common breeding birds that did lose ground are two species of thrushes, with their declining distribution possibly brought about by similar environmental factors.

• Since populations of most plant species remained unaffected by detectable changes between 2001 and 2009, they are not featured in Table 1 above. Changes in the population sizes of common plant species are mostly the result of population increases rather than declines. Losers and winners form a conglomerate of species characterized by widely differing ecological demands. Population sizes of some species typical of rich pastures—such as Red Clover, Dandelion or Bugleweed—are increasing. However, another nutrient indicator, Crested Dog’s Tail, is receding. As regards mountain plant populations, the Purple Mountain Saxifrage is spreading, while the Blunt-leaved Willow is drawing back.

• Most moss species did not undergo significant changes between 2001 and 2009, either, so they are not covered by Table 1 above. All changes in population size recorded for common moss species are increases. These winners include typical forest mosses such as Hypnum cupressiforme, Fissidens taxifolius, Plagiomnium affine agg., Drepanocladus uncinatus or Blepharostoma trichophyllum, which have particularly increased at the subalpine level. The reason for this trend is not known, but Drepanocladus uncinatus and Blepharostoma trichophyllum may possibly benefit from more deadwood being available again.

• Since rare species only occur in a few BDM sampling areas, the Z8 indicator is not suited to document the development of their population sizes.
 
 
Complete Data Sheet
 

> Complete Z8 datasheet (13,5 MB)
 
 
Further Information
 

In charge of this indicator
Tobias Roth, roth@hintermannweber.ch, +41 (0)61 717 88 62

Related indicators
> Z12: Diversity of Species Communities

Weblinks
> www.bafu.admin.ch/?lang=en: comprehensive information on the Federal Office for the Environment FOEN
> www.lfi.ch/index-en.php: comprehensive information on the Swiss National Forest Inventory
> www.wsl.ch/land/products/webflora/welcome-en.ehtml: distribution maps of Swiss vascular plant species
> http://www.nism.uzh.ch/index.php?content=einleitung&lang=en: inventory of the Swiss bryophyte flora
> www.birdlife.ch/d/home_e.html: Swiss Association for the Protection of Birds (mostly in French and German)
> www.vogelwarte.ch/home.php?lang=e&cap=index: comprehensive information on the Common Breeding Bird Survey (MHB) and the Swiss Bird Index (SBI) of the Swiss Ornithological Institute Sempach

Appendices
> Appendix 1: Widespread species in Switzerland’s landscapes
> Appendix 2: Most common species in Switzerland’s habitats
> Appendix 3: Complete breeding bird species list
> Appendix 4: Complete butterfly species listr
> Appendix 5: Complete vascular plant species list
> Appendix 6: Complete moss species list
> Appendix 7: Complete mollusk species list
 
 
 
 
     
       
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