Abundance and composition of invertebrate-feeding leeches in relation to fish status in ponds

Figures & data

Figure 1. Location of study sites in eastern Poland (Lublin region). Red ovals outline pond complexes comprising the study ponds. Inset shows location of the study region within Poland.

Table I. Mean numerical percentages of leech species in ponds differing in fish status.

Species	Bottom traps		Near-surface traps
	Low-fish ponds	High-fish ponds	Low-fish ponds	High-fish ponds
Erpobdellidae
Dina apathyi	0.7	0.6	0.0	0.0
Dina lineata	0.0	0.6	0.0	2.4
Erpobdella monostriata	0.0	3.4	1.9	0.5
Erpobdella nigricollis	33.4	3.3	13.6	13.3
Erpobdella octoculata	56.5	72.8	66.4	55.9
Erpobdella testacea	0.0	5.5	7.1	0.0
Glossiphoniidae
Alboglossiphonia heteroclita	0.0	0.0	0.0	0.1
Alboglossiphonia hyalina	0.0	0.0	0.0	1.8
Glossiphonia complanata	4.6	0.0	0.8	5.4
Helobdella stagnalis	4.8	13.0	10.2	17.9
Hemiclepsis marginata	0.0	0.8	0.0	1.9
Theromyzon tessulatum	0.0	0.0	0.0	0.9

Figure 2. Mean (± standard error) relative leech abundances (individuals per 10 traps) from bottom traps, Erpobdellidae (a), Glossiphoniidae (b), and from near-surface traps, Erpobdellidae (c) and Glossiphoniidae (d), over time in low-fish ponds and high-fish ponds.

Figure 3. Ordination biplot from redundancy analysis showing relationships between leech species and environmental variables. Leech abundance estimates were based on bottom trap catches. Species abbreviations are based on the first three letters of genus and species names (see Table I). Variable abbreviations: low-fish ponds (LOW FISH), high-fish ponds (HIGH FISH), dissolved oxygen (DO), conductivity (COND), total nitrogen concentration (TN), total phosphorus concentration (TP), percentage share of emergent vegetation (EMERG VEG).