Topographic Wetness Index calculation guidelines based on measured soil moisture and plant species composition

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985939%3A_____%2F21%3A00547082" target="_blank" >RIV/67985939:_____/21:00547082 - isvavai.cz</a>

Alternative codes found

RIV/60460709:41320/21:89417 RIV/60460709:41330/21:89937

Result on the web

<a href="https://doi.org/10.1016/j.scitotenv.2020.143785" target="_blank" >https://doi.org/10.1016/j.scitotenv.2020.143785</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.scitotenv.2020.143785" target="_blank" >10.1016/j.scitotenv.2020.143785</a>

Result language

angličtina

Original language name

Topographic Wetness Index calculation guidelines based on measured soil moisture and plant species composition

Original language description

Soil moisture controls environmental processes and spedes distributions, but it is difficult to measure and interpolate across space. Topographic Wetness Index (TWI) derived from digital elevation model is therefore often used as a proxy for soil moisture. However, different algorithms can be used to calculate TWI and this potentially affects TWI relationship with soil moisture and species assemblages. To disentangle insufficiently-known effects of different algorithms on TWI relation with soil moisture and plant species composition, we measured the root-zone soil moisture throughout a growing season and recorded vascular plants and bryophytes in 45 temperate forest plots. For each plot, we calculated 26 TWI variants from a LiDAR-based digital terrain model and related these TWI variants to the measured soil moisture and moisture-controlled species assemblages of vascular plants and bryophytes. A flow accumulation algorithm determined the ability of the TWI to predict soil moisture, while the flow width and slope algorithms had only a small effects. The TWI calculated with the most often used single-flow D8 algorithm explained less than half of the variation in soil moisture and species composition explained by the TWI calculated with the multiple-flow FD8 algorithm. Flow dispersion used in the 1D8 algorithm strongly affected the TWI performance, and a flow dispersion dose to 1.0 resulted in the TWI best related to the soil moisture and spedes assemblages. Using downslope gradient instead of the local slope gradient can strongly decrease TWI performance. Our results clearly showed that the method used to calculate TWI affects study conclusion. However, TMI calculation is often not specified and thus impossible to reproduce and compare among studies. We therefore provide guidelines for TWI calculation and recommend the FD8 flow algorithm with a flow dispersion close to 1.0, flow width equal to the raster cell size and local slope gradient for TWI calculation.

Czech name

—

Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10618 - Ecology

Project

<a href="/en/project/GA17-13998S" target="_blank" >GA17-13998S: Forest microclimate - neglected link between plant diversity and climate change</a><br>

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2021

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Science of the Total Environment

ISSN

0048-9697

e-ISSN

1879-1026

Volume of the periodical

757

Issue of the periodical within the volume

25 February

Country of publishing house

NL - THE KINGDOM OF THE NETHERLANDS

Number of pages

10

Pages from-to

143785

UT code for WoS article

000604432900063

EID of the result in the Scopus database

2-s2.0-85096555917