Elve Lode & Martin Küttim

Background information of groundwater dependent ecosystems (GDE) on Estonian

Gauja-Koiva river basin

5-6 July, 2018, Salacgriva, Latvia

5-6 July, 2018, Salacgriva, Latvia

Content

• Some facts about the Koiva river

• Something about GDEs

• „Ecological data base“ of GDEs in Koiva river catchment

• Known spring-fens in Koiva river catchment

5-6 July, 2018, Salacgriva, Latvia

Location of Koiva river and it catchment

Length of the Koiva river (in Estonia) = 26 km, i.e. between 228-254 km from the mouth of the Gauja river Catchment area (in Estonia) = 1302 km2 (ca 25% from all Gauja river catchment) (EELIS data base; Eesti NSV jõgede, ojade ja kraavide ametlik nimestik, 1986)

5-6 July, 2018, Salacgriva, Latvia

Koiva river stream network

The longest river in the catchment is the Mustjõgi river (L= 84 km, F= 1820 km2, in Estonia 994 km2)Totally there are about 50 flowing water bodies in the Koiva river basin data base, but 80% of them are brooks (EELIS data base; Eesti NSV jõgede, ojade ja kraavide ametlik nimestik, 1986)

5-6 July, 2018, Salacgriva, Latvia

Groundwater-Dependent Ecosystems (GDEs)are ecosystems that rely upon groundwater for their continued existence

Groundwater-Dependent Terrestrial Ecosystems

(GWDTEs) are wetlands which critically depend on groundwater flows and /or chemistries

P

1. General atmosphere-ground conditions

a) Availability of sufficient water (mainly from the atmosphere)

b) Availability to form recharge and discharge areas

on the landscape

Prerequisites for occurrence of GDEs or GWDTEs

5-6 July, 2018, Salacgriva, Latvia

2. Interaction between general hydro-geological conditions

and surface topology, i.e. type of GDEs or GWDTEsa) Availability to form regional groundwater dependent ecosystems on the landscape

or

a) Availability to form local groundwater dependent ecosystems on the landscape

https://wetlandinfo.ehp.qld.gov.au/wetlands/ecology/aquatic-ecosystems-natural/groundwater-dependent/spring-

ecosystems-of-the-surat-and-southern-bowen-basins/#top-overview

5-6 July, 2018, Salacgriva, Latvia

3. Ecosystem dynamics within non-disturbed

atmosphere-hydro-geologic-surface topology conditions, - as a referencea) Dynamics of discharge area hydrology, i.e. water quantity and quality in wet phase and dry phase

b) Dynamics of ecosystems plant cover, i.e. horizontal zonation and it dynamics in wet phase and dry phase

Type 1a Wetlands located in off-stream environments,

within floodplains

Example of ecological zonation of regional groundwater

dependent ecosystem on the ground

1. Zone of permanent inundation and/or flowing discharge

2. Zone of aeration and reduced saturation

3. Saturated shoulder of the mound

4. Non-wetland area

5. Discharge tail during the wet phase

6. Wetland to non-wetland transition zone

7. Discharge tail during dry phase

8. Discharge tail during the dry phase

https://wetlandinfo.ehp.qld.gov.au/wetlands/ecology/aquatic-ecosystems-

natural/groundwater-dependent/spring-ecosystems-of-the-surat-and-southern-bowen-

basins/type-1

5-6 July, 2018, Salacgriva, Latvia

Example of ecological zonation of regional

groundwater dependent ecosystem

Type 2 Semi-permanent brackish, palustrine wetlands with

minor wetland soils and minor vegetation cover, mainly

connected to regional groundwater systems

Type 3 Permanent to semi-permanent riverine wetlands with minor

wetland soils and moderate vegetation cover, sourced from local and

regional groundwater systems and significantly influenced by surface

water flows

Example of ecological zonation of mixed

groundwater dependent ecosystem and

influenced by surface water flows

https://wetlandinfo.ehp.qld.gov.au/wetlands/ecology/aquatic-ecosystems-natural/groundwater-dependent/spring-ecosystems-of-the-surat-and-southern-bowen-basins/#type

type-2 & type-3

5-6 July, 2018, Salacgriva, Latvia

Type 4 & 5 Semi-permanent fresh riverine-to-palustrine wetlands with minor wetland soils and moderate vegetation cover,

mainly connected to local groundwater systems.

Examples of ecological zonation of local groundwater dependent ecosystem

https://wetlandinfo.ehp.qld.gov.au/wetlands/ecology/aquatic-ecosystems-natural/groundwater-dependent/spring-ecosystems-of-the-surat-and-southern-bowen-

basins/#type 4 & type-5

5-6 July, 2018, Salacgriva, Latvia

Questions needed to answer* What is the list of the terminology what we will agree to use?Groundwater-Dependent Ecosystems (GDEs)(are ecosystems that rely upon groundwater for their continued existence)

or

Groundwater dependent terrestrial ecosystems (GWDTEs)

(are wetlands which critically depend on groundwater flows and /or chemistries)

* What is the spring mire?Not all fens are the spring mires and

not all springs are forming spring mires!

* What are the threshold values (TVs) for the GDEs or GWDTE?(Groundwater dependent terrestrial ecosystem (GWDTE) threshold values (TVs) are groundwater chemical

concentrations which have been derived from empirical evidence)

* How to mesaure and report the ecosystem conditions?1) General atmosphere-ground conditions

2) Interaction between general hydro-geological conditions and surface topology

3) Ecosystem dynamics within non-disturbed atmosphere-hydro-geologic-surface topology conditions, as a

reference

4) Disturbances

5-6 July, 2018, Salacgriva, Latvia

„Ecological data base“ of Koiva river catchment

Red polygons1. Matsi spring mire – 3 areas

2. Varstu spring mire – 1 area

Green polygons3. 1411A, 1421

4. 3131, 3113

5-6 July, 2018, Salacgriva, Latvia

Spring fens in South-Estonia (Ilomets et al 2012)

Symbols: green dots - calcareous spring fens in good state; blue squares - drained sites; red triangles - abandoned tufa deposits or damaged sites

Spring fens in Estonia (Paal & Leibak 2011)

5-6 July, 2018, Salacgriva, Latvia

Spring fen vegetation

5-6 July, 2018, Salacgriva, Latvia

Spring fen vegetation: community composition

• Cotton-grasses:• Eriophorum angustifolium• E. latifolium

• Schoenus ferrugineus

• Sesleria caerulea

• Sedges:• Carex davalliana• C. hostiana• C. dioica• C. diandra• C. rostrata

• Pinguicula vulgaris

• etc

5-6 July, 2018, Salacgriva, Latvia

Environmental factors controlling the vegetation composition

• High water table

• Low fluctuation of water table

• Stabile temperature

• Low availability of nutrients

• High pH

• Precipitation of tufa (?)

5-6 July, 2018, Salacgriva, Latvia

Water table ~ vegetation (Küttim 2013)

5-6 July, 2018, Salacgriva, Latvia

Spring fens in Koiva catchment

• Matsi

• Varstu

• More?

5-6 July, 2018, Salacgriva, Latvia

Matsi spring fens (Ilomets et al 2014)

• Location: Võru county, Varstu parish, Matsi village• Geologically: in Võru-Hargla valley, by the Mustjõgi river• Area: 4.6 ha (in three parts)

• Northern part 3.4 ha

• In a relatively good state, but surrounded by the ditches and a road• Mostly open habitats, but wooded in drier part

• Vegetation: • Dominated everywhere by Menyanthes trifoliata• Sedges (Carex lasiocarpa, C. rostrata)• Abundant Epipactis palustris (protected II cat.!)

5-6 July, 2018, Salacgriva, Latvia

Matsi spring fens (Ilomets et al 2014)

5-6 July, 2018, Salacgriva, Latvia

Matsi spring fens (Ilomets et al 2014)

• Oppressional springs (igritsevad) in the northern and central part, overflowing water in the south

• Tufa precipitation in the northern and central part, iron precipitation in the south

• Water table near surface(5...11 cm below surface)

• Minor slope (1 m per 50 m)

• pH 6.9...7.7

• Sedge-brown moss peat with tufa layers

5-6 July, 2018, Salacgriva, Latvia

5-6 July, 2018, Salacgriva, Latvia

5-6 July, 2018, Salacgriva, Latvia

Thank You!