Korean stream types based on benthic macroinvertebrate communities according to stream size and altitude

Figures & data

Figure 1. Map of South Korea, the southern half of the Korean Peninsula bordering the East Sea and Yellow Sea, Northeast Asia; and the location (grey triangles) of the 1,020 study sites (13,366 samples). Thin lines show the five main rivers with national rivers and thick line indicate the four major river basins (Hangang, Nakdonggang, Geumgang, and Yeongsangang-Seomjingang river basin).

Figure 2. Box and whisker plots of measures of Strahler order versus physical characteristics of the classes of streams based on the 1:120,000-scale for stream width (a), altitude (b), stream temperature (c), streambed substratum (d), stream depth (e), and flow velocity (f). Fifth and 95th percentiles (black circles), 10th and 90th percentiles (vertical dashed line), quartiles (box ends), medians (solid horizontal lines within boxes), and averages (dotted horizontal lines within boxes).

Table 1. Spearman's rank correlations (r) among physical environmental variables.

	Stream order	Stream width	Altitude (m a.s.l.)	Water temperature (°C)	Substrate (phi)
Stream width	0.822**
Altitude (m a.s.l.)	−0.178**	−0.272**
Water Temperature (°C)	0.246**	0.207**	−0.454**
Substrate (phi)	0.112**	0.178**	−0.400**	0.203**
Depth (cm)	0.395**	0.428**	−0.045	0.020	0.0123

**p < 0.01.

Figure 3. Distribution patterns of FFGs along with stream size characterized by both stream order and stream width. (a) Mean individual abundance/m² and standard error of CF and SH according to stream order; (b) relative composition (%) of FFG according to stream order; (c) mean individual abundance/m² and standard error of CF and SH according to stream width; and (d) relative composition (%) of FFG according to stream width.

Table 2. Classification of stream size focused on vertical (stream order) and lateral (stream width) gradients. A large number of samples (13,366) were used for classification of stream size based on distribution patterns of FFGs with the classification approach for streams and rivers of the EPA (Flotemersch et al. 2006).

Variable	Type	EPA range	Fixed range	Number of samples
Stream order	Wadeable	1st–3rd or 4th	1st	655
			2nd	2,749
			3rd	3,902
	Transitional	3rd–5th	4th	3,258
			5th	1,735
	Non-wadeable	4th–8th	6th	949
			7th	118
Stream width	Small	–	<15 m	500
	Middle	–	15–30 m 30–75 m	2,184 3,377
	Large	–	75–150 m 150–300 m 300–600 m >600 m	3,887 2,267 917 234
Total of each variable				13,366

Figure 4. Distribution patterns of FFGs along with altitude: (a) mean individual abundance and standard error of CF and SH and (b) relative composition (%) of FFG.

Table 3. Classifications of altitude focused on altitude. A large number of samples (13,366) were used for classification of altitude based on distribution patterns of FFGs with descriptors of the ecoregion of the WFD (WFD 2000).

Variable	Type	WFD range (m a.s.l.)	Fixed range (m a.s.l.)	Number of samples
Altitude	Low	<200 m	<25 m	2,305
			25–50 m	2,944
			50–100 m	2,960
			100–200 m	2,531
	Middle	200–800 m	200–300 m	1,312
			300–450 m	840
	High	>800 m	>450 m	474
Total				13,366

Figure 5. Five stream types of South Korea focused on vertical, lateral, and altitude characteristics of streams using types of stream size and altitude. A large number of samples (13,366) were used for the classification of Korean stream types. Wadeable streams were divided into mountain, highland, and lowland wadeable streams. Non-wadeable streams were divided into lowland non-wadeable streams and rivers.

Figure 6. Distribution patterns of CF and SH along with stream types and clustering characteristics of stream types: (a) mean individual abundance/m² and standard error of CF and SH according to stream types; and (b) dendrogram of five stream types based on mean individual abundance/m² of benthic macroinvertebrates using the McQuitty's linkage and Sorensen's (Bray–Curtis) distance method (MO, mountain stream; HI, highland stream; LW, lowland wadeable stream; LN, lowland non-wadeable stream; RI, river).

Figure 7. Canonical correspondence analysis (CCA) multivariate ordination diagram relating 1,020 sampling sites to three physical environmental variables in South Korea. The plots present the ordination of sampling sites (a), and arrow length is proportional to relative importance (b) of the stream order, stream width, and altitude. W: wadeable stream, NW: non-wadeable stream.

Table 4. Result of ordinations by canonical correspondence analysis (CCA) of data on 1020 sampling sites within a physical environmental (a) and Pearson correlation coefficients for the first three axes (b).

Variable	Axis 1	Axis 2	Axis 3
(a) Axis summary statistics of CCA results
Eigenvalue	0.335	0.133	0.044
% variance explained in taxa data	2.5	1.0	0.3
Cumulative % variance explained	2.5	3.4	3.8
Total variance in the species data	13.608
(b) Correlations coefficient for three variables
Altitude	0.811**	0.028	−0.019
Stream order	−0.402**	−0.498**	−0.088**
Stream width	−0.325**	−0.341**	−0.221**

**p < 0.01.

Table 5. Twenty-five indicator species (p < 0.05) sensitive to stream types, along with stream size and altitude in each stream type: (i) preference for mountain stream, (ii) preference for highland stream, (iii) preference for lowland wadeable stream, (iv) preference for lowland non-wadeable stream, and (v) preference for rivers. Monte Carlo randomization test results provided the proportion-based p-value indicating the statistical significance of the observed indicator value.

	Indicator value calculated with ISA
Scientific name	(i)	(ii)	(iii)	(iv)	(v)	p-value
(a) Mountain stream
Rhyacopila articulata Morton	13	0	0	0	0	0.001
Arctopsyche ladogensis Kolenati	13	0	0	0	0	0.001
Protonemura KUa	5	0	0	0	0	0.001
Megarcys ochracea Klapalek	5	0	0	0	0	0.001
Taenionema KUc	4	0	0	0	0	0.001
(b) Highland stream
Epeorus maculatus Tshernova	0	1	0	0	0	0.006
Suragina KUb	0	1	0	0	0	0.004
Heptagenia kyotoensis Gose	0	1	0	0	0	0.009
Rhyacophila yamanakensis Iwata	0	7	1	1	0	0.001
Ecdyonurus dracon Kluge	3	8	1	0	0	0.001
(c) Lowland wadeable stream
Baetis pseudothermicus Kluge	0	0	5	0	0	0.001
Chaetogaster limnaei limnaei	0	0	3	0	0	0.012
Ceratopogonidae	0	1	4	1	0	0.021
Asellus	0	0	7	2	0	0.002
Orthetrum albistylum Selys	0	0	2	1	0	0.024
(d) Lowland non-wadeable stream
Hydropsyche KD	0	0	0	2	0	0.004
Ephoron shigae Takahashi	0	0	0	2	0	0.002
Stenelmis vulgaris Nomura	0	0	0	2	0	0.010
Macronema radiatum McLachlan	0	0	1	10	0	0.001
Corbicula fluminea Müller	0	0	2	10	1	0.001
(E) River
Macrobrachium nipponense De haan	0	0	0	0	6	0.001
Micronecta sedula Horváth	0	0	0	1	12	0.001
Branchiura sowerbyi Beddard	0	0	0	0	3	0.001
Palaemon paucidens De Haan	0	0	0	0	2	0.003
Eriocheir sinensis Milne-Edwards	0	0	0	0	1	0.018

Flotemersch JE, Stribling JB, Paul MJ. 2006. Concepts and approaches for the bioassessment of non-wadeable streams and rivers. Washington (DC): US Environmental Protection Agency, Office of Research and Development.

 Google Scholar

WFD. 2000. E.U. Directive 2000/60/EC of the European parliament and of the council establishing a framework for the community action in the field of water policy. Brussels: The European Parliament and the Council of the European Union.

 Google Scholar