Corresponding author: Martin Reiss (
Academic editor: D.S. Schmeller
Headwater springs in the German Low Mountain Ranges are local ecotone habitats and biogeographical islands embedded in and interlinked with their adjacent landscape. The structure of forests reflects the eco-hydrological conditions in substrate type occurrence, microhabitat richness and biodiversity in forest springs. This study considers effects from different forest land cover by comparing spring habitats in deciduous beech forests and coniferous spruce forests on eco-hydrological structures and biodiversity. Study areas include six different forest landscapes in the Low Mountain Ranges in Central Germany in Hesse and Thuringia. Hydro-morphological structure mapping and invertebrate sampling was executed within a multi-habitat sampling regime, which involves sampling plots being allocated according to the cover ratio of the occurring substrata. Aquatic and terrestrial spring zones are considered with respect to an ecotone approach. Some
Reiss M, Chifflard P (2018) Different forest cover and its impact on eco-hydrological traits, invertebrate fauna and biodiversity of spring habitats. Nature Conservation 27: 85–99.
Mountainous headwater springs are mostly small water bodies where dominant groundwater occurs at the surface to form an intermittent or permanent discharge influenced by subsurface interflow and overland flow (
The objective of this study is to determine effects from different forest cover by comparing spring habitats in deciduous and coniferous forests on eco-hydrological structures and biodiversity. This research focuses on impacts from forest types as a determinant of the occurrence of corresponding microhabitat types, its substrate type composition and diversity, as well as its specific colonisation by invertebrates. Here, acidity is also considered, because conifer forests could be contributing to acidification of surface waters (
Study sites are located in 6 different forested parts of the Low Mountain Ranges in Central Germany (Fig.
Study sites in Central Germany.
Overview of the study sites within deciduous forest land cover.
Deciduous Forest | Hainich | Krofdorf | Keller-wald | Vogels-berg | Rhön | Burg-wald | Total |
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Geology | Limestone | Greywacke, Clay Shale | Volcanic rocks | Sandstone | |||
No. of objects | 4 | 16 | 27 | 9 | 5 | 0 | 61 |
% | 7% | 26% | 44% | 15% | 8% | – | 100% |
Overview of the study sites within deciduous forest land cover.
Coniferous Forest | Hainich | Krofdorf | Keller-wald | Vogels-berg | Rhön | Burg-wald | Total |
---|---|---|---|---|---|---|---|
Geology | Limestone | Greywacke, Clay Shale | Volcanic rocks | Sandstone | |||
No. of objects | 2 | 3 | 3 | 0 | 0 | 17 | 25 |
% | 8% | 12% | 12% | – | – | 68% | 100% |
Data analysis was based on a data set from a study on the microhabitat-fauna-relationship and the importance of invertebrate substrate preferences (
Adjacent biotope field mapping was done by observing a length of 100 metres from the springhead and by considering four separated quarters, orientated by compass directions (Fig.
Four-segment approach of adjacent biotope types mapping for springs.
Hydro-morphological structure mapping and invertebrate sampling was conducted using a novel integrated technique for multi-habitat sampling (
Data preparation was carried out by filtering and sorting all data related to 100% of the deciduous and coniferous forest cover within the four-segment approach of the adjacent biotope type field mapping procedure. Multiple methods were used to characterise diversity indices: Margalef richness (d) after
The results from hydro-physical-chemical
Hydro-physical-chemical measurements of deciduous forest and coniferous forest land cover.
Parameter | Wtemp | pH | EC | O2 Conc. | O2 Satur. | |||||
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°C | µS*cm-1 | mg/l | % | |||||||
Max | 15.9 | 13.4 | 8.5 | 8.3 | 960 | 790 | 13.0 | 14.8 | 134% | 142% |
75-Q | 12.4 | 11.5 | 7.9 | 7.4 | 320 | 230 | 9.7 | 10.7 | 107% | 102% |
Median | 10.2 | 10.3 | 7.7 | 5.4 | 200 | 180 | 8.9 | 7.0 | 92% | 75% |
25-Q | 8.1 | 8.1 | 7.5 | 4.9 | 130 | 140 | 7.1 | 4.3 | 79% | 43% |
Min | 3.1 | 3.0 | 6.0 | 4.0 | 70 | 110 | 3.6 | 2.4 | 38% | 25% |
The acidification of spring water seems to be one major effect in conifer forest springheads, showing that the pH measurements giving a much lower median value in coniferous forest with pH 5.4, than in deciduous forest with pH 7.7 (Fig.
pH of springs of coniferous (left boxplot) and deciduous (right boxplot) forest land cover.
Microhabitats, which cover ratios for deciduous and coniferous forest springs (Fig.
Cover ratio of microhabitats in deciduous (left) and coniferous (right) forest headwater springs. Substrate terminology: Argyllal – Agry; Psammal – Psam; Psammopelal – Pspl; Akal – Akal; Microlithal – Mikrol; Mesolithal – Mesol; Macrolithal – Makrol; Megalithal – Megal; Emergent macrophytes – eMphy; Submerged macrophytes – sMphy; Moss cushions – Mosses; Fine roots – Roots; Xylal (Dead Wood) – Xylal; Coarse particular organic material – CPOM; Coniferous litter – Clit; Fine particular organic material – FPOM;
Overall, 52 taxa and 2617 individuals in springs of deciduous forest land cover and 33 taxa and 326 individuals in springs of coniferous forest land cover were found. Tables
Taxa list of springs within deciduous forest land cover. x – good substrate type preference identification; xx – very good substrate type preference identification; m – mosses (spring dwelling taxa are in bold).
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577 | 26 | 22.2 | x | |||||
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198 | 11 | 18.0 | x | |||||
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402 | 26 | 15.5 | x | |||||
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110 | 10 | 11.0 | x | x | ||||
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112 | 15 | 7.5 | x | |||||
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50 | 7 | 7.1 | x | |||||
188 | 34 | 5.5 | x | ||||||
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177 | 38 | 4.7 | x | |||||
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165 | 36 | 4.6 | xx | |||||
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17 | 4 | 4.3 | xx | |||||
86 | 29 | 3.0 | x | ||||||
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20 | 7 | 2.9 | x | x | ||||
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16 | 6 | 2.7 | xx | |||||
71 | 28 | 2.5 | x | x | |||||
58 | 23 | 2.5 | x | x | |||||
19 | 8 | 2.4 | |||||||
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7 | 3 | 2.3 | xx | |||||
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30 | 13 | 2.3 | xx | |||||
17 | 8 | 2.1 | |||||||
57 | 27 | 2.1 | x | ||||||
2 | 1 | 2.0 | |||||||
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8 | 4 | 2.0 | x | |||||
2 | 1 | 2.0 | x | x | |||||
72 | 37 | 1.9 | x | m | |||||
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27 | 15 | 1.8 | x | |||||
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7 | 4 | 1.8 | m | |||||
7 | 4 | 1.8 | x | ||||||
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30 | 18 | 1.7 | x | x | ||||
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13 | 8 | 1.6 | x | |||||
8 | 5 | 1.6 | x | x | |||||
17 | 11 | 1.5 | |||||||
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4 | 3 | 1.3 | xx | |||||
11 | 10 | 1.1 | xx | ||||||
4 | 4 | 1.0 | x | ||||||
1 | 1 | 1.0 | |||||||
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1 | 1 | 1.0 | ||||||
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3 | 3 | 1.0 | xx | |||||
1 | 1 | 1.0 | |||||||
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2 | 2 | 1.0 | x | xx | x | |||
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1 | 1 | 1.0 | ||||||
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3 | 3 | 1.0 | xx | |||||
1 | 1 | 1.0 | |||||||
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1 | 1 | 1.0 | xx | |||||
4 | 4 | 1.0 | x | ||||||
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1 | 1 | 1.0 | ||||||
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1 | 1 | 1.0 | ||||||
2 | 2 | 1.0 | x | m | |||||
1 | 1 | 1.0 | |||||||
1 | 1 | 1.0 | x | xx | |||||
1 | 1 | 1.0 | |||||||
2 | 2 | 1.0 | |||||||
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1 | 1 | 1.0 | ||||||
Averages | Ø 50 | Ø 10 | Ø 3 | ||||||
Identification of substrate type preferences | 7 | 3 | 20 | 9 | 7 | 3 | |||
Identification of substrate type preferences / total no. of taxa | 0.14 | 0.06 | 0.38 | 0.17 | 0.14 | 0.06 | |||
Identification of substrate type preferences in total | 49 |
Taxa list of springs within coniferous forest land cover. x: good substrate type preference identification; xx: very good substrate type preference identification; m – mosses; Ml – Megalith (spring dwelling taxa are in bold).
Invertebrates – taxa and abundances | Invertebrates – substrate preference | ||||||||
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Taxa | Individuals (Ind.) | Springs | Ind./springs | Pspl | Microl | CPOM | Xylal | eMphy | Others |
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77 | 2 | 38.5 | x | |||||
14 | 1 | 14.0 | x | x | |||||
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34 | 3 | 11.3 | x | |||||
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5 | 1 | 5.0 | x | x | ||||
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24 | 5 | 4.8 | xx | |||||
32 | 7 | 4.6 | x | ||||||
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16 | 4 | 4.0 | x | |||||
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3 | 1 | 3.0 | x | xx | x | |||
11 | 4 | 2.8 | x | ||||||
44 | 18 | 2.4 | x | ||||||
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18 | 8 | 2.3 | x | x | ||||
6 | 3 | 2.0 | x | ||||||
4 | 2 | 2.0 | x | ||||||
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4 | 2 | 2.0 | xx | |||||
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2 | 1 | 2.0 | x | |||||
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2 | 1 | 2.0 | x | |||||
3 | 2 | 1.5 | |||||||
3 | 3 | 1.0 | x | ||||||
3 | 3 | 1.0 | xx | ||||||
2 | 2 | 1.0 | x | x | |||||
1 | 1 | 1.0 | |||||||
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1 | 1 | 1.0 | x | |||||
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3 | 3 | 1.0 | x | x | ||||
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1 | 1 | 1.0 | x | |||||
1 | 1 | 1.0 | x | x | m | ||||
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1 | 1 | 1.0 | ||||||
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2 | 2 | 1.0 | m | |||||
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1 | 1 | 1.0 | ||||||
2 | 2 | 1.0 | x | m | |||||
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1 | 1 | 1.0 | xx | |||||
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3 | 3 | 1.0 | xx | Ml | ||||
1 | 1 | 1.0 | x | xx | |||||
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1 | 1 | 1.0 | ||||||
Averages | Ø 10 | Ø 3 | Ø 4 | ||||||
Identification of substrate type preferences | 6 | 2 | 21 | 6 | 1 | 4 | |||
Identification of substrate type preferences / total no. of taxa | 0.18 | 0.06 | 0.64 | 0.24 | 0.03 | 0.12 | |||
Identification of substrate type preferences in total | 40 |
Diversity indices in deciduous and coniferous forest headwater springs.
Forest land cover | Margalef richness (d) | Shannon index (H’) | Pilou’s evenness (J’) |
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Deciduous Forest | 6.48 | 2.78 | 0.70 |
Coniferous Forest | 5.53 | 2.65 | 0.76 |
Results show three main forest land cover impacts on eco-hydrological structures and biodiversity in mountainous headwater springs concerning deciduous and coniferous forest: 1) Acidification in conifer forest springs; 2) Higher cover ratios of organic substrate type based microhabitats in deciduous forest springs; 3) Higher biodiversity in species richness and total number of individuals as well as abundances in deciduous forest springs.
Acidification of springs in coniferous forests of the German Low Mountain Ranges is a well-known problem, especially in siliceous springs with poor acid buffer capacities and can causes a decrease in the total number of species and individuals (
Higher cover ratios of organic substrate type based microhabitats in deciduous forest springs compared with springs in coniferous forest can be seen as a higher hydro-morphological representation of specific microhabitats (e.g. emergent macrophytes or CPOM). However, conifer forest springs have the same quantitative share of occurring substrate types. CPOM (Coarse particular organic material), mainly composed by leaf litter from deciduous trees, is more important as allochthonous organic material as the most important food source for spring fauna communities with a high proportion of primary consumers in particular like herbivorous shredders (e.g.
Higher biodiversity in species richness, total number of individuals as well as abundances in deciduous forest springs in contrast to conifer forest springs, are the most obvious impacts caused by different forest stands. The result of a higher amount of spring dwelling taxa in conifer forest springs than in deciduous forest springs, in proportion to the total number of all found taxa, is consistent with findings by
Different forest land cover causes considerable contrasts in microhabitat structures; obvious organic substrate type composition and cover ratios; as well as differences in species richness and invertebrate abundance of spring habitats in deciduous and coniferous forest. This means, land cover as an ecological mesoscale, properly determined by different forest types, has an impact on eco-hydrological structures and biodiversity on the micro scale. It implies an essential consideration for adjacent biotope type mapping and is an important integrative parameter for spring habitat assessment approaches. Furthermore, the recognition of substrate preferences of invertebrates, within an ecotone based assessment approach, characterises microhabitats explicitly for all parts of a springhead, regarding aquatic and terrestrial spring habitat zones. Here, the importance of forest land cover and the substrate type diversity relationship is taken into account within an ecological spring habitat assessment methodology and characterises its consequences on invertebrate biodiversity. Therefore, negative effects from forest management practices (e.g. forest conversion) within a nature conservation perspective can be included in decision-making and action plans to realise national or regional strategies on biodiversity.
Taxa determination for specific taxonomic groups were done by some colleagues with special thanks to Dr. Peter Martin (Kiel, Germany) for