Research Article |
Corresponding author: Matthew Bird ( mattsbird@gmail.com ) Academic editor: Mariano Michat
© 2016 Renzo Perissinotto, Matthew Bird, David Bilton.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Perissinotto R, Bird MS, Bilton DT (2016) Predaceous water beetles (Coleoptera, Hydradephaga) of the Lake St Lucia system, South Africa: biodiversity, community ecology and conservation implications. ZooKeys 595: 85-135. https://doi.org/10.3897/zookeys.595.8614
|
Water beetles are one of the dominant macroinvertebrate groups in inland waters and are excellent ecological indicators, reflecting both the diversity and composition of the wider aquatic community. The predaceous water beetles (Hydradephaga) make up around one-third of known aquatic Coleoptera and, as predators, are a key group in the functioning of many aquatic habitats. Despite being relatively well-known taxonomically, ecological studies of these insects in tropical and subtropical systems remain rare. A dedicated survey of the hydradephagan beetles of the Lake St Lucia wetlands (South Africa) was undertaken between 2013 and 2015, providing the first biodiversity census for this important aquatic group in the iSimangaliso Wetland Park, a UNESCO World Heritage Site within the Maputaland biodiversity hotspot. A total of 32 sites covering the entire spectrum of waterbody types were sampled over the course of three collecting trips. The Lake St Lucia wetlands support at least 68 species of Hydradephaga, a very high level of diversity comparing favourably with other hotspots on the African continent and elsewhere in the world and a number of taxa are reported for South Africa for the first time. This beetle assemblage is dominated by relatively widespread Afrotropical taxa, with few locally endemic species, supporting earlier observations that hotspots of species richness and centres of endemism are not always coincident. Although there was no significant difference in the number of species supported by the various waterbody types sampled, sites with the highest species richness were mostly temporary depression wetlands. This contrasts markedly with the distribution of other taxa in the same system, such as molluscs and dragonflies, which are most diverse in permanent waters. Our study is the first to highlight the importance of temporary depression wetlands and emphasises the need to maintain a variety of wetland habitats for aquatic conservation in this biodiverse region.
Aquatic beetles, biodiversity census, Afrotropical region, wetland conservation, iSimangaliso Wetland Park
The aquatic Adephaga, or Hydradephaga, with over 5300 species currently described worldwide, account for around one third of the total aquatic and semi-aquatic beetles described to date (
Hydradephaga are important predators in aquatic systems, consuming a wide variety of benthic and pelagic invertebrates, mainly other insects and crustaceans (
Lake St Lucia on the north-east coast of South Africa is a prominent coastal system, historically communicating freely with the open ocean most of the time. Recently, freshwater deprivation related to anthropogenic manipulation and a regional drought has led to large-scale desiccation and closure of its mouth since July 2002 (
Lake St Lucia itself sits within the iSimangaliso Wetland Park, South Africa’s first UNESCO World Heritage Site, and a Ramsar wetland of global significance due to its exceptional biodiversity. iSimangaliso and the coastal plains of KwaZulu-Natal form part of Maputaland, a centre of endemism and transition zone between tropical lowlands to the north and temperate regions to the south and west. Warm currents flowing south from Mozambique mean that the region’s biota is now dominated by tropical species at what is a relatively high southern latitude (
A detailed biodiversity census has already been completed for some prominent invertebrate groups at St Lucia/iSimangaliso, including the bivalves (Nel et al. 2013), gastropods (
Samples were collected in and around Lake St Lucia (27°52'0"S to 28°24'0"S and 32°21'0"E to 32°34'0"E), a large (~ 300 to 350 km2) estuarine lake in northern KwaZulu-Natal, South Africa (Fig.
Aquatic beetles were collected from a variety of freshwater habitats surrounding Lake St Lucia and from submerged vegetation habitats at the margins of the estuary itself. A total of 32 sites comprising a wide variety of waterbodies was sampled over the course of the three collection trips (Fig.
In addition to sampling of the estuarine lake itself (Fig.
Examples of the wetland habitat types encountered in the St Lucia section of the iSimangaliso Wetland Park during the course of this study. a Depression (site 13) b valley bottom (channelled, site 17) c valley bottom (unchannelled, site 19) d river (site 20) e wetland flat (site 18) f seepage (site 32) g estuarine lake shore (site 31) h estuarine lake body (site 30).
Geographic position and classification of the waterbodies sampled during this study. Sampling took place during the three collecting trips to Lake St Lucia during November 2013, July 2014 and January/February 2015. Classification (wetland type) follows the hydrogeomorphic (HGM) approach of
Site | GPS (D°M’S”) | Wetland type | Region | November 2013 | July 2014 | January/February 2015 | |
---|---|---|---|---|---|---|---|
1 | 28°20'53.33"S | 32°23'38.42"E | River (pool) | WS | x | x | |
2 | 28°20'54.23"S | 32°22'59.68"E | Depression | WS | x | ||
3 | 28°21'10.77"S | 32°23'7.88"E | Channelled valley bottom | WS | x | ||
4 | 28°21'7.52"S | 32°23'24.04"E | Channelled valley bottom | WS | x | ||
5 | 28°17'55.76"S | 32°23'10.62"E | River (riparian zone) | WS | x | ||
6 | 28°15'26.06"S | 32°23'36.51"E | Depression | WS | x | x | x |
7 | 28°15'11.10"S | 32°23'39.95"E | Depression | WS | x | x | x |
8 | 28°12'25.44"S | 32°24'22.97"E | Depression (artificial) | WS | x | ||
9 | 28°15'19.19"S | 32°23'38.53"E | Depression | WS | x | ||
10 | 28°17'19.08"S | 32°23'16.53"E | Depression | WS | x | ||
11 | 28°18'31.52"S | 32°26'54.54"E | Un-channelled valley bottom | ES | x | ||
12 | 28°17'00.81"S | 32°27'43.78"E | Depression | ES | x | ||
13 | 28°16'6.26"S | 32°28'00.02"E | Depression | ES | x | x | |
14 | 28°16'10.26"S | 32°27'35.43"E | Depression | ES | x | x | |
15 | 28°18'25.29"S | 32°26'59.88"E | Un-channelled valley bottom | ES | x | ||
16 | 28°14'15.05"S | 32°24'32.30"E | Depression | WS | x | ||
17 | 28°15'1.00"S | 32°24'9.85"E | Channelled valley bottom | WS | x | ||
18 | 28°17'44.59"S | 32°22'58.49"E | Flat | WS | x | ||
19 | 28°07'10.99"S | 32°31'8.98"E | Un-channelled valley bottom | ES | x | ||
20 | 28°12'21.75"S | 32°29'27.07"E | River (main channel) | ES | x | ||
21 | 28°20'59.06"S | 32°25'50.76"E | Depression | ES | x | ||
22 | 28°18'59.92"S | 32°26'10.64"E | Depression | ES | x | ||
23 | 28°20'7.84"S | 32°26'10.36"E | Depression | ES | x | ||
24 | 28°22'44.46"S | 32°25'20.13"E | River (connected to estuary) | ES | x | ||
25 | 28°21'59.12"S | 32°25'42.10"E | Depression | ES | x | ||
26 | 27°58'32.33"S | 32°21'51.14"E | Depression | FB | x | ||
27 | 27°57'31.50"S | 32°21'41.82"E | Depression | FB | x | x | |
28 | 27°58'25.01"S | 32°22'16.02"E | Channelled valley bottom | FB | x | ||
29 | 28°00'51.44"S | 32°21'54.93"E | Channelled valley bottom | FB | x | x | |
30 | 28°00'47.95"S | 32°22'00.92"E | Estuarine lake | FB | x | x | |
31 | 28°02'9.17"S | 32°21'42.78"E | Estuarine lake shore (light trap) | FB | x | x | x |
32 | 28°13'14.56"S | 32°29'12.45"E | Seep | ES | x |
Sweep netting was employed on all three sampling trips as the primary method for collecting aquatic beetles. A long-handled square-framed sweep net with a 30 cm mouth and 1 mm mesh was swept repeatedly from the water surface to the bottom substrate and back to the surface following a protocol similar to that of
To provide an environmental context for the beetle samples and baseline information for the aquatic habitats of St Lucia, basic in situ physico-chemical parameters were measured at each site. Temperature, conductivity, salinity, pH, turbidity and dissolved oxygen were recorded using a YSI 6600-V2 multi-system probe. Due to technical problems, physico-chemical measurements were not taken during November 2013.
Records of aquatic Coleoptera previously collected from Lake St Lucia and the fresh waterbodies in its immediate vicinity were obtained from the Iziko
All identifications were conducted by DTB, using a wide range of literature and, in many cases, comparison with named museum material. All identifications were based, at least in part, on the study of male genitalia, unless otherwise stated. Digital photographs of both ventral and dorsal habitus of each species were taken using a Canon Powershot G11 or a Canon EOS 600D digital camera fitted with a Sigma 50mm f/2.8 EX DG macro lens for larger specimens (≥ 1.5 cm) and a Nikon SMZ25 microscope for smaller specimens (< 1.5 cm). Image stacks were produced by hand, and combined using Zerene Stacker software (www.zerenesystems.com). Photographs were then compiled into an annotated and illustrated species list of all Hydradephaga identified within the November 2013, July 2014 and January/February 2015 surveys, as well as those collected from 2008 and 2012 during ad hoc collections (Appendix
Median and range values for each of the physico-chemical variables were calculated for each survey. The measured physico-chemical variables were then explored using multivariate analyses to assess how the physico-chemistry of freshwater wetlands at St Lucia varies amongst waterbody types and also spatially across the coastal plain. Principal Component Analysis (PCA) was used to depict patterns in physico-chemistry on a two-dimensional plot. Variables with non-normal distributions were log-transformed where appropriate. Conductivity was not depicted in the PCA plot as it was highly collinear with salinity (r = 0.996) and thus we regarded conductivity as a redundant variable.
Spatial patterns in the composition of aquatic beetle communities amongst the wetlands at St Lucia were analysed using multivariate techniques. Beetle presence-absence data were converted to a Bray-Curtis dissimilarity matrix and depicted on a two-dimensional plot using non-metric multidimensional scaling (MDS). Permutational MANOVA (PERMANOVA,
All tests were performed using an a priori significance level of α = 0.05. PCA and MDS were performed using PRIMER v6 software (
Waterbodies encountered on the St Lucia coastal plain were mostly groundwater-fed depressions and valley bottom wetlands. These freshwater wetlands appeared to be abundant in the study area. True rivers (flow contained within a single main channel) were less common, but several small rivers were encountered and sampled (e.g. Nkazana Stream, site 20). Most waterbodies were small (generally < 2 ha) and shallow (<1 m maximum depth), although some of the valley bottom wetland sites formed part of larger systems (e.g. site 19 forms part of the Mfabeni mire). Due to a general predominance of lentic or slow-flowing systems, rocky biotopes were virtually absent and sites were extensively vegetated by a mix of emergent and submerged macrophytes, which formed the primary structural habitat for all sites sampled.
Surface water temperatures were warm and in summer the median recorded water temperature was as high as ~29 °C (Table
Physico-chemical variables recorded during the July 2014 and January/February 2015 surveys. Median, minimum and maximum values are reported for each survey. Physico-chemical data were not collected in November 2013. Depth was not recorded in July 2014. Site 31 is not reported as this was a terrestrial light trapping location.
Survey date | Site | Temperature (°C) | Conductivity (mS.cm-1) | Salinity (PSU) | pH | Turbidity (NTU) | Dissolved O2 (mg.L-1) | Depth (m) |
---|---|---|---|---|---|---|---|---|
July 2014 |
1 | 16.59 | 0.254 | 0.14 | 8.61 | 16.4 | 4.72 | - |
2 | 16.08 | 0.471 | 0.29 | 6.81 | 883.6 | 5.15 | - | |
3 | 16.50 | 0.601 | 0.35 | 6.58 | 194.8 | 1.81 | - | |
4 | 17.08 | 0.153 | 0.09 | 4.60 | 570.5 | 1.40 | - | |
5 | 17.03 | 6.726 | 4.42 | 6.56 | 40.2 | 2.45 | - | |
6 | 19.07 | 0.437 | 0.24 | 7.07 | 831.3 | 1.61 | - | |
7 | 22.81 | 0.504 | 0.25 | 5.22 | 75.8 | 3.58 | - | |
8 | 21.65 | 0.475 | 0.24 | 7.00 | 529.1 | 8.50 | - | |
9 | 21.02 | 0.489 | 0.26 | 7.23 | 183.2 | 7.88 | - | |
10 | 19.17 | 0.943 | 0.53 | 7.33 | 1220.2 | 7.83 | - | |
11 | 16.98 | 0.104 | 0.05 | 5.97 | 15.0 | 3.20 | - | |
12 | 22.62 | 0.221 | 0.10 | 6.46 | 36.7 | 10.05 | - | |
13 | 23.02 | 0.344 | 0.16 | 6.52 | 11.2 | 8.08 | - | |
14 | 21.96 | 0.240 | 0.11 | 6.60 | 3.2 | 4.53 | - | |
15 | 19.38 | 0.214 | 0.10 | 5.44 | 47.0 | 2.99 | - | |
Median | 19.17 | 0.437 | 0.24 | 6.58 | 75.8 | 4.53 | - | |
Minimum | 16.08 | 0.104 | 0.05 | 4.60 | 3.2 | 1.40 | - | |
Maximum | 23.02 | 6.726 | 4.42 | 8.61 | 1220.2 | 10.05 | - | |
January / February 2015 |
1 | 24.02 | 0.378 | 0.18 | 6.62 | 9.6 | 1.00 | 0.34 |
6 | 34.37 | 1.034 | 0.50 | 5.06 | 30.2 | 10.23 | 0.31 | |
7 | 32.93 | 0.923 | 0.45 | 3.88 | 6.1 | 7.52 | 0.43 | |
13 | 22.47 | 0.592 | 0.28 | 5.69 | 197.6 | 4.39 | 0.38 | |
14 | 35.61 | 0.342 | 0.16 | 6.89 | 29.4 | 9.92 | 0.27 | |
16 | 31.87 | 2.551 | 1.29 | 7.57 | 613 | 3.58 | 0.24 | |
17 | 24.57 | 1.866 | 0.95 | 4.22 | 21.8 | 4.23 | 0.31 | |
January / February 2015 |
18 | 34.23 | 0.237 | 0.11 | 7.32 | 191.2 | 7.42 | 0.26 |
19 | 37.78 | 0.392 | 0.18 | 5.49 | 18.9 | 7.25 | 0.25 | |
20 | 24.33 | 0.411 | 0.20 | 5.96 | 34.8 | 1.27 | 0.37 | |
21 | 33.28 | 0.180 | 0.08 | 6.77 | 352.3 | 7.26 | 0.20 | |
22 | 34.73 | 0.827 | 0.40 | 4.82 | 25.6 | 8.13 | 0.50 | |
23 | 34.66 | 0.414 | 0.19 | 5.96 | 36.6 | 8.76 | 0.30 | |
24 | 25.84 | 9.752 | 5.48 | 7.65 | 25.8 | 4.32 | 0.70 | |
25 | 29.03 | 1.703 | 0.85 | 8.28 | 17.4 | 8.95 | 2.00 | |
26 | 26.09 | 0.323 | 0.15 | 7.21 | 1310.5 | 1.50 | 0.08 | |
27 | 22.03 | 0.598 | 0.29 | 7.42 | 151 | 1.82 | 0.70 | |
28 | 28.69 | 20.150 | 11.97 | 7.98 | 30.6 | 9.82 | 0.15 | |
29 | 26.73 | 1.496 | 0.75 | 6.90 | 306.3 | 5.53 | 0.25 | |
30 | 22.03 | 46.640 | 30.31 | 8.51 | 14.2 | 7.14 | 0.12 | |
32 | 30.03 | 0.710 | 0.35 | 7.55 | 14.6 | 6.98 | 0.05 | |
Median | 29.03 | 0.710 | 0.35 | 6.89 | 30.2 | 7.14 | 0.30 | |
Minimum | 22.03 | 0.180 | 0.08 | 3.88 | 6.1 | 1.00 | 0.05 | |
Maximum | 37.78 | 46.640 | 30.31 | 8.51 | 1310.5 | 10.23 | 2.00 |
The PCA plot (Fig.
Principal components analysis (PCA) of physico-chemical variables. Sites are shown according to region and site numbers coded as B (July 2014) or C (January/February 2015). Physico-chemical data were not collected during the first survey (November 2013). The first two principal component axes are displayed, with PC1 and PC2 explaining 34.7 and 28.2% of the variation in the physico-chemical data, respectively. Table
Appendix
Hydradephagan beetles collected from St Lucia during the course of this study. The sites are listed from which each taxon was collected on each of the three sampling trips. Site numbers 1–32 correspond to those listed in Table
Sampling date | Region | |||||
---|---|---|---|---|---|---|
November 2013 | July 2014 | January/February 2015 | WS | ES | FB | |
Gyrinidae: | ||||||
Gyrinus natalensis Régimbart, 1892 | 4 | X | ||||
Dineutus subspinosus (Klug, 1834) | 21, 23, 29 | X | X | |||
Haliplidae: | ||||||
Haliplus natalensis Wehncke, 1880 | 27 | X | ||||
Peltodytes sp. | 6, 27 | X | X | |||
Noteridae: | ||||||
Canthydrus apicicornis Régimbart, 1895 | 7, 8, 13 | 6, 7, 13, 14, 17, 18, 22, 25 | X | X | ||
Canthydrus marshalli Balfour-Browne, 1939 | 6 | X | ||||
Canthydrus notula (Erichson, 1843) | 6, 7, 8, 9, 10, 14, 15 | 6, 7, 14, 16, 17, 21, 22, 23, 27, 29 | X | X | X | |
Canthydrus quadrivittatus (Boheman, 1848) | 13 | 1, 6, 13, 14, 16, 17, 18, 22, 23, 27 | X | X | X | |
Canthydrus sedilloti Régimbart, 1895 | 1, 6, 13, 14, 16, 17, 22, 23 | X | X | |||
Hydrocanthus grandis (Laporte, 1835) | 14 | X | ||||
Hydrocanthus micans Wehncke, 1883 | 1, 6, 14, 17, 22, 23, 29 | X | X | X | ||
Hydrocanthus ferruginicollis Régimbart, 1895 | 27 | X | ||||
Synchortus imbricatus (Klug, 1853) | 1, 7, 16, 17, 25, | X | X | |||
Synchortus desaegeri Gschwendtner, 1935 | 23 | X | ||||
Neohydrocoptus aethiopicus (Balfour-Browne, 1961) | 2 | 1, 7, 20, 23, 27 | X | X | X | |
Neohydrocoptus angolensis (Peschet, 1925) | 1, 2, 3 | 1, 6, 14, 25, 27 | X | X | X | |
Dytiscidae: | ||||||
+Copelatus cf. ejactus Omer-Cooper, 1965 | 17, 18, 22, 26, 29 | X | X | X | ||
Copelatus erichsoni Guérin-Méneville, 1849 | 17, 20, 26, 27, 29 | X | X | X | ||
Copelatus pulchellus (Klug, 1834) | 17, 26, 29 | X | X | |||
Cybister gschwendtneri Guignot, 1935 | 27, 31 | 14, 27 | X | X | ||
Cybister marginicollis Boheman, 1848 | 27, 31 | 11 | 7, 14, 18, 22, 27, 31 | X | X | X |
Cybister natalensis (Wehncke, 1876) | 29 | X | ||||
Cybister senegalensis Aubé. 1838 | 6, 27 | X | X | |||
Cybister tripunctatus africanus Laporte, 1835 | 14, 21, 27, 29, 31 | X | X | |||
Cybister bimaculatus Aubé, 1838 | 21 | X | ||||
Cybister ertli Zimmermann, 1917 | 13 | 14 | X | |||
Cybister vicinus Zimmermann, 1917 | 21, 23, 27, 29, 31 | X | X | |||
Cybister vulneratus Klug, 1834 | 30 | 4 | 6, 14, 16, 17, 18, 19, 23, 27, 29, 31 | X | X | X |
Rhantaticus congestus (Klug, 1833) | 27 | 21, 22, 23, 27, 29, 31 | X | X | ||
Eretes sticticus (Linnaeus, 1767) | 21 | X | ||||
Hydaticus bivittatus Laporte, 1835 | 27 | X | ||||
Hydaticus exclamationis Aubé, 1838 | 27, 29 | X | ||||
Hydaticus flavolineatus Boheman, 1848 | 27 | X | ||||
+Hydaticus cf. natalensis Guignot, 1951 | 27 | X | ||||
Hydaticus matruelis Clark, 1864 | 27 | X | ||||
Hydaticus servillianus Aubé, 1838 | 27, 30 | 6, 11 | 14, 23, 26, 27, 29 | X | X | X |
Bidessus sharpi Régimbart, 1895 | 6, 14, 16, 21, 27, 29 | X | X | X | ||
Clypeodytes meridionalis Régimbart, 1895 | 3 | 14, 20 | X | X | ||
Hydroglyphus farquharensis (Scott, 1912) | 6, 14, 16, 17, 18, 21, 22, 27, 28, 29, 31 | X | X | X | ||
Hydroglyphus lineolatus (Boheman, 1848) | 21, 31 | X | X | |||
Hydroglyphus zanz ibarensis (Régimbart, 1906) | 2, 3, 10 | 6, 13, 14, 16, 17, 21, 22, 29, 32 | X | X | X | |
Leiodytes hieroglyphicus (Régimbart, 1894) | 7, 17 | X | X | |||
Pseuduvarus viticollis (Boheman, 1848) | 32 | X | ||||
Uvarus gschwendtneri (Guignot, 1942) | 6, 17, 18, 22, 23, 27, 29 | X | X | X | ||
Hydrovatus acuminatus Motschulsky, 1859 | 1, 6, 13, 14, 16, 22, 23, 25, 27, 29 | X | X | X | ||
Hydrovatus cribratus Sharp, 1882 | 6, 7, 14, 16 | X | X | |||
Hydrovatus dentatus Bilardo & Rocchi, 1990 | 14, 17, 21 | X | X | |||
Hydrovatus eximius Biström, 1997 | 29 | X | ||||
Hydrovatus nefandus Omer-Cooper, 1957 | 23, 27 | X | X | |||
Hydrovatus nigricans Sharp, 1882 | 22, 23 | X | ||||
Hydrovatus oblongipennis Régimbart, 1895 | 15 | 23 | X | |||
Hydrovatus obsoletus Peschet, 1922 | 23 | X | ||||
Hydrovatus villiersi Guignot, 1955 | 14 | X | ||||
Hydrovatus visendus Biström, 1997 | 6, 18 | X | ||||
Herophydrus guineensis (Aubé, 1838) | 6, 7, 14, 16, 21, 27, 29 | X | X | X | ||
Herophydrus inquinatus (Boheman, 1848) | 27 | 27, 29 | X | |||
+Herophydrus nigrescens Biström & Nilsson, 2002 | 6, 25, 27 | X | X | X | ||
Herophydrus nodieri (Régimbart, 1895) | 27 | 6, 11, 12 | 6, 7, 13, 14, 22, 23, 25, 27, 29 | X | X | X |
Heterhydrus senegalensis (Laporte, 1835) | 6, 14, 22, 23 | X | X | |||
Hyphydrus caffer Boheman, 1848 | 14, 25 | X | ||||
Hyphydrus cycloides Régimbart, 1889 | 14, 18, 22, 23, 29 | X | X | X | ||
Hyphydrus signatus Sharp, 1882 | 27 | 6, 27, 29 | X | X | ||
Methles cribratellus (Fairmaire, 1880) | 15 | 1, 6, 7, 13, 16, 17, 18, 22, 23, 27, 31 | X | X | X | |
Derovatellus cf. natalensis Omer-Cooper, 1965 | 27, 30 | 16, 17, 19, 22, 23, 27, 29 | X | X | X | |
Laccophilus canthydroides Omer-Cooper, 1957 | 17, 22, 23, 29 | X | X | X | ||
Laccophilus cryptos Biström, Nilsson & Bergsten, 2015 | 2 | 14, 21, 22, 23, 27, 29 | X | X | X | |
Laccophilus contiro Guignot, 1952 | 6, 14, 22, 23, 27, 31 | X | X | X | ||
Laccophilus simplicistriatus Gschwendtner, 1932 | 7, 27 | 7, 15 | 21, 23, 26, 27, 29, 31 | X | X | X |
Hydradephagan taxa reported at Lake St Lucia and its immediate surrounds prior to our surveys are listed in Table
Hydradephagan beetles previously recorded from the Lake St Lucia system and surrounding waterbodies. Literature sources indicated by letters as follows: (a)
Family | Genus | Species | Publication | Years recorded | Location |
---|---|---|---|---|---|
Gyrinidae | Dineutus | D. subspinosus* | (c) | 2002/2003 | FWW |
Gyrinus | G. natalensis* | (c) | 2002/2003 | FWW | |
Noteridae | Canthydrus | C. notula* | (c) | 2002/2003 | FWW |
Canthydrus spp. 1–4 | (c) | 2002/2003 | FWW | ||
Hydrocanthus | H. ferruginicollis* | (a), (b) | 1964/1965 | FWS | |
H. funebris Fairmaire, 1869 | (c) | 2002/2003 | FWW | ||
Hydrocanthus spp. 1–2 | (c) | 2002/2003 | FWW | ||
Hydrocoptus | Hydrocoptus spp. 1–2 | (c) | 2002/2003 | FWW | |
Synchortus | Synchortus spp. 1–2 | (c) | 2002/2003 | FWW | |
Dytiscidae | Rhantus | Rhantus sp. | (c) | 2002/2003 | FWW |
Copelatus | C. sylvaticus Guignot, 1952 | (c) | 2002/2003 | FWW | |
Cybister | C. guignoti Gschwendtner, 1936 | (c) | 2002/2003 | FWW | |
C. marginicollis* | (c) | 2002/2003 | FWW | ||
C. natalensis* | UKZN | 2012 | FB, DP | ||
C. vulneratus* | (c) | 2002/2003 | FWW | ||
Cybister sp. | (c) | 2002/2003 | FWW | ||
Aethionectes | Aethionectes sp. | (c) | 2002/2003 | FWW | |
Rhantaticus | R. congestus* | (c) | 2002/2003 | FWW | |
UKZN | 2012 | DP | |||
Hydaticus | H. bivittatus* |
|
Not specified | SL | |
H. servillanus* | UKZN | 2012 | FB | ||
Hydaticus sp. | ISAM | 1988 | KB | ||
Pseuduvarus | P. viticollis* | (c) | 2002/2003 | FWW | |
Hydrovatus | H. madagascariensis Régimbart, 1903 |
|
1956 | DF | |
Herophydrus | H. nigrescens* | (d) | 1975 | LT | |
Herophydrus spp. 1–3 | (c) | 2002/2003 | FWW | ||
Hydrovatus spp. 1–2 | (c) | 2002/2003 | FWW | ||
Hyphydrus | H. cycloides* | (c) | 2002/2003 | FWW | |
H. grandis Laporte, 1835 | (c) | 2002/2003 | FWW | ||
H. maculatus Babington, 1841 | (c) | 2002/2003 | FWW | ||
H. signatus* | (a), (b) | 1964/1965 | FWS | ||
Methles | Methles sp. | (c) | 2002/2003 | FWW | |
Derovatellus | Derovatellus spp. 1–2 | (c) | 2002/2003 | FWW | |
Laccophilus | L. australis Biström, Nilsson & Bergsten, 2015 | (e) | 1975 | LT | |
L. cryptos* | (e) | 1975 | LT | ||
L. secundus Régimbart, 1895 | (e) | ? | ? | ||
Laccophilus spp. 1–5 | (c) | 2002/2003 | FWW |
Aquatic beetle assemblage composition of the sites sampled during 2013-2015 differed across both regions and waterbody types (Fig.
Multidimensional scaling (MDS) plot depicting the similarity of sites sampled in this study in terms of beetle assemblage composition. Symbols on the plot have been coded in terms of a region and b waterbody type. Convex hulls (dashed lines) have been overlaid on each plot to clarify groupings according to region/waterbody type.
Non-parametric permutational MANOVA (PERMANOVA) results for models comparing beetle assemblage composition. Assemblage composition at St Lucia was compared across (a) regions, and (b) waterbody types. The multivariate models tested for differences between group centroids in Bray-Curtis dissimilarity space. WS – western shores; FB – False Bay; ES – eastern shores; Dep. – depression wetland; ELS – estuarine lake shore; VB – valley bottom.
(a) | Post hoc pairwise comparisons | |||||||
---|---|---|---|---|---|---|---|---|
Source | df | SS | MS | F | P | Groups | t | P |
Region | 2 | 12087 | 6043.7 | 1.6119 | 0.0311* | WS, FB | 1.6932 | 0.0014* |
Residual | 35 | 131230 | 3749.4 | WS, ES | 0.7968 | 0.8007 | ||
Total | 37 | 143320 | FB, ES | 1.2882 | 0.0471* | |||
(b) | Post hoc pairwise comparisons | |||||||
Source | df | SS | MS | F | P | Groups | t | P |
Waterbody type | 3 | 16804 | 5601.4 | 1.5174 | 0.0277* | Dep., ELS | 1.3635 | 0.0368* |
Residual | 32 | 118130 | 3691.6 | Dep., River | 1.4480 | 0.0205* | ||
Total | 35 | 134930 | Dep., VB | 1.1185 | 0.2522 | |||
ELS, River | 1.3239 | 0.0973 | ||||||
ELS, VB | 0.7162 | 0.9276 | ||||||
River, VB | 1.1209 | 0.1860 |
Non-parametric Kruskal-Wallis tests indicate that species richness did not vary significantly between regions (KW-H2, 38 = 1.0025, p = 0.6058) or waterbody types (KW-H5, 38 = 2.273, p = 0.8102) at St Lucia. Mean richness across all sites and sampling trips was 8.5±9.3 (±SD) taxa per site, the very high standard deviation indicating that the number of taxa recorded per site was extremely variable. The highest recorded richness for an individual site visit was 35 taxa, collected from site 27 (Mpophomeni pan) at False Bay in January/February 2015. Sites 14 (eastern shores), 23 (eastern shores) and 29 (Dukandlovu Pan, False Bay) all yielded more than 25 taxa during January/February 2015. Yet only a single taxon was recorded from site 7 (eastern shores) in November 2013, sites 1 (western shores), 9 (western shores), 12 (eastern shores) and 14 (eastern shores) in July 2014 and site 28 (False Bay) in January/February 2015 (Fig.
Box-plots comparing the median and spread of species richness (number of hydradephagan taxa per site) among a regions and b waterbody types at St Lucia during the sampling period 2013–2015. The data representing number of taxa per site are also reported (c). Site numbers in (c) are coded as A (first survey – November 2013), B (second survey – July 2014) or C (third survey – January/February 2015). Kruskal-Wallis tests indicated that species richness did not vary significantly among regions (KW-H2, 38 = 1.0025, p = 0.6058) or waterbody types (KW-H5, 38 = 2.273, p = 0.8102).
This study reveals that the St Lucia lake system and its associated wetlands support at least 68 species of Hydradephaga. It is currently estimated that ca. 410 species of Hydradephaga occur in southern Africa as a whole (
The species richness observed at St Lucia is comparable with that recorded in a number of tropical locations worldwide. For example,
Five species of Hydradephaga found during our surveys are apparently new to the fauna of South Africa (Table
The hydradephagan fauna of Lake St Lucia is dominated by relatively widespread Afrotropical taxa (see distribution records in Appendix
Only three species (Cybister vulneratus Klug, 1834, Hydaticus servillianus Aubé, 1838 and Derovatellus cf. natalensis Omer-Cooper, 1965) were found in the margins of Lake St Lucia itself, the overwhelming majority of species being associated with small wetlands in the park. False Bay sites supported relatively distinctive beetle assemblages, including species which were not recorded elsewhere, whereas the faunas of the eastern and western shores largely overlapped (Fig.
Although hydradephagan assemblage composition varied significantly between different areas of St Lucia, species richness did not. Similarly, richness did not differ significantly between the different types of waterbodies sampled. Although there was no significant difference in richness among the waterbody types, the sites with the very highest richness were mostly temporary depression wetlands; a pattern which contrasts markedly with other taxa such as molluscs and dragonflies which are most diverse in permanent waters. With the exception of site 29 (a channelled valley bottom wetland) all sites that yielded 20 or more taxa from a single visit were such depression wetlands (sites 6, 14, 22, 23 and 27), highlighting the importance of this habitat for aquatic conservation in the region for the first time.
Due to unprecedented drought conditions in the region and past anthropogenic activities, there have been significant changes in the St Lucia system in recent decades. The estuary mouth closed in 2002 and large-scale desiccation of the lake basins began in 2004 (
The St Lucia system, whilst being dominated by relatively widespread Afrotropical water beetles, supports what appears to be one of the most diverse assemblages of Hydradephaga reported in southern Africa. In line with the high species richness and diversity in other groups investigated to date (e.g. odonates, bivalves, gastropods, crabs), the results of the current study further reinforce the biodiversity importance of the iSimangaliso Wetland Park. Much remains to be investigated, particularly with regard to the environmental factors that support this exceptional biodiversity, and how these may be impacted by climatic and other anthropogenic changes in the future.
The iSimangaliso Wetland Park Authority and Ezemvelo KZN Wildlife are thanked for providing permits and logistical support for this study. We are very grateful to Stephanie Martin, Ricky Taylor, Lynette Clennell, Jacqueline Raw, Nasreen Peer and Nelson Miranda for assisting with field collections. Simon van Noort (ISAM, Cape Town), Ruth Müller (
Annotated and illustrated checklist of the Hydradephaga recorded from wetlands of the Lake St Lucia system, 2013–2015.
The following list includes photographs of all species recorded during the dedicated water beetle surveys conducted by the authors during the period 2013 to 2015. With the exception of Laccophilus australis Biström, Nilsson & Bergsten, 2015, this includes all species reliably recorded from the region.
Standing waters.
Widespread to Western, Central and Eastern Africa.
Standing waters.
Widespread to Western, Central and Eastern Africa.
Previously recorded by
Standing water, possibly associated with charophytes
Widespread to Western, Central and Eastern Africa
This may be a new species, as only P. quadratus Régimbart, 1895 is recorded from South Africa (perhaps in error – see van Vondel, 2010) and this does not match the specimens collected. Only two females were found during this survey, making either positive identification or description impossible at present.
Unknown.
Standing waters, in dense vegetation.
Kwa-Zulu Natal and Mozambique. Endemic to South-East Africa.
Not previously recorded from St Lucia. Recorded at Western Shores and Eastern Shores in July 2014 and January/February 2015, during the course of this study.
Standing waters, in dense vegetation.
Kwa-Zulu Natal and Central Africa.
Standing waters, in dense vegetation.
Widespread throughout Africa.
Previously recorded by
Standing waters, in dense vegetation.
Widespread to Central Africa.
Not previously recorded from St Lucia. Recorded at Western Shores, Eastern Shores and False Bay in July 2014 and January/February 2015, during the course of this study.
Standing waters, in dense vegetation.
Widespread to Western, Central and East Africa.
Not previously recorded from St Lucia. Recorded at Western Shores and Eastern Shores in January/February 2015, during the course of this study.
Standing waters, in dense vegetation.
Botswana, Zimbabwe, Mozambique and to Central and Eastern Africa. New record for South Africa.
Standing waters, in dense vegetation.
Eastern Cape, Kwa-Zulu Natal, Botswana, Mozambique, Zimbabwe, Zambia and to Western, Central and Eastern Africa.
Not previously recorded from St Lucia. Recorded at Western Shores, Eastern Shores and False Bay in January/February 2015, during the course of this study.
Fresh water bodies.
South Africa, Botswana, Zimbabwe, Mozambique to Central and Eastern Africa.
Previously recorded by
Standing waters, in dense vegetation.
Kwa-Zulu Natal, Mozambique to Western, Central and Eastern Africa.
Not previously recorded from St Lucia. Recorded at Western Shores and Eastern Shores in January/February 2015, during the course of this study.
Standing waters, in dense vegetation.
Botswana to Central and Eastern Africa. New record for South Africa.
Dense vegetation.
Western Cape to Central and Eastern Africa.
Not previously recorded from St Lucia. Recorded at Western Shores, Eastern Shores and False Bay in July 2014 and January/February 2015, during the course of this study.
Dense vegetation.
Kwa-Zulu Natal to Western and Eastern Africa.
Not previously recorded from St Lucia. Recorded at Western Shores, Eastern Shores and False Bay in July 2014 and January/February 2015, during the course of this study.
Thought to occur largely in standing waters. Possibly endemic to South Africa.
Previously known only from the Limpopo province.
Not previously recorded from St Lucia. Recorded at Western Shores, Eastern Shores and False Bay in January/February 2015, during the course of this study.
Copelatus formosus Wollaston, 1867.
Standing waters, especially shallow pools. Likely to be a complex of closely related species.
Widespread to Western, Central and Eastern Africa.
Not previously recorded from St Lucia. Recorded at Western Shores, Eastern Shores and False Bay in January/February 2015, during the course of this study.
Copelatus africanus Sharp, 1882; Copelatus basalis Boheman, 1848; Copelatus discoideus Sharp, 1882; Colymbetes marginipennis Laporte, 1835; Copelatus obtusus Boheman, 1848; Copelatus strigulosus Sharp, 1882.
Standing waters, especially shallow pools.
Widespread to Western and Eastern Africa.
Ponds and lagoons.
Widespread to Western and Eastern Africa, but not known to be common.
Cybister auritus Gerstaecker, 1871; Cybister filicornis Sharp, 1882; Cybister marginicollis annulicornis Griffini, 1892.
Ponds and lagoons.
Widespread to Western, Central and Eastern Africa.
Previously recorded by
Cybister circumcinctus Gschwendtner, 1932
Ponds and lagoons.
Widespread to Central Africa.
Cybister convexiusculus H.J. Kolbe, 1883; Cybister marginellus Régimbart, 1895; Cybister rufiventris Régimbart, 1895; Cybister senegalensis var. irroratus H.J. Kolbe, 1883; Cybister senegalensis var. seidlitzii Ragusa, 1888.
Ponds and lagoons.
Widespread to Western, Central and Eastern Africa.
Cybister aegyptiacus Peyron, 1856; Trogus haagi Wehncke, 1876; Trochalus meridionalis Gené, 1836; Trogus punctipennis Taschenberg, 1883.
Abundant in ponds and lagoons.
Widespread to Mediterranean basin.
Not previously recorded from St Lucia. Recorded at Eastern Shores and False Bay in January/February 2015, during the course of this study.
Cybister aequatorius Zimmermann, 1917; Cybister regimbarti Wilke, 1920.
Ponds and lagoons.
Widespread in Africa.
Ponds and lagoons.
Swaziland, Zimbabwe, Mozambique, Malawi to Central and Eastern Africa. New record for South Africa.
Ponds and lagoons.
Mpumalanga and widespread to Central and Eastern Africa.
Not previously recorded from St Lucia. Recorded at Eastern Shores and False Bay in January/February 2015, during the course of this study.
Cybister binotatus Klug, 1835; Cybister bivuolnerus Aubé, 1838; Cybister madagascariensis Aubé, 1838.
Ponds and lagoons.
Widespread to Mediterranean basin.
Previously recorded by
Hydaticus rochasi Perroud & Montrousier, 1864; Hydaticus signatipennis Laporte, 1835
Likely to be a species complex.
Widespread in Old World tropics.
Obtained from available museum collections and ad hoc collections by the University of KwaZulu-Natal in 2012. Recorded at Eastern Shores and False Bay in November 2013 and January/February 2015, during this study.
Eunectes helvolus Klug, 1834; Eunectes punctatus Zoubkoff, 1837; Eunectes occidentalis Erichson, 1847; Eunectes conicollis Wollaston, 1861; Eunectes subcoriaceus Wollaston, 1861; Eretes subdiaphanus Wollaston, 1861.
Open ponds with bare substrate.
Widespread in Afrotropics, Middle East to Americas.
Hydaticus bivittatus var. sharpi Peschet, 1917.
Ponds.
Widespread to Western, Central and Eastern Africa.
Obtained from available museum collections and ad hoc collections by the South African National Collection of Insects. The year is not specified. Specimen found at the St Lucia lake body and immediate surrounds. Recorded at False Bay in January/February 2015, during the course of this study.
Ponds.
Widespread to Western, Central and Eastern Africa.
Ponds.
Widespread to Western, Central and Eastern Africa.
Ponds.
The identity of this species is currently uncertain, and will require comparisons with type specimens. Apparently endemic to KwaZulu-Natal.
Hydaticus matruelis var. fuscicollis Régimbart, 1895; Hydaticus graueri Ahlwarth, 1921.
Ponds.
Widespread to Western, Central and Eastern Africa.
Hydaticus discoidalis Hope, 1843; Hydaticus flavomarginatus Zimmermann, 1920.
Ponds.
Widespread to Western, Central and Eastern Africa.
Not previously recorded from St Lucia. Recorded at Western Shores, Eastern Shores and False Bay in November 2013, July 2014 and January/February 2015, during the course of this study.
Bidessus factor Omer-Cooper, 1959; Bidessus granulum Régimbart, 1859; Bidessus sharpi nigeriensis Omer-Cooper, 1974; Bidessus sedilloti Régimbart, 1859; Bidessus sharpi sudanensis Omer-Cooper, 1974.
Ponds, in shallow water with dense vegetation.
Widespread to Western, Central and Eastern Africa.
Not previously recorded from St Lucia. Recorded at Western Shores, Eastern Shores and False Bay in January/February 2015, during the course of this study.
Clypeodytes seminulum Régimbart, 1895; Clypeodytes cribrosus var. voiensis Guignot, 1936.
Ponds, in shallow water with dense vegetation.
Widespread to Western, Central and Eastern Africa.
Not previously recorded from St Lucia. Recorded at Western Shores and Eastern Shores in July 2014 and January/February 2015, during the course of this study.
Guignotus bivirgatus Guignot, 1952; Guignotus browni Pederzani, 1982; Guignotus harrisoni Omer-Cooper, 1955.
Ponds.
Widespread to Eastern Africa.
Not previously recorded from St Lucia. Recorded at Western Shores, Eastern Shores and False Bay in January/February 2015, during the course of this study.
Ponds, over exposed substrates.
Widespread in Southern Africa.
Not previously recorded from St Lucia. Recorded at Eastern Shores and False Bay in January/February 2015, during the course of this study.
Bidessus orarius Omer-Cooper, 1931.
Ponds.
Widespread in Southern and Eastern Africa.
Not previously recorded from St Lucia. Recorded at Western Shores, Eastern Shores and False Bay in July 2014 and January/February 2015, during the course of this study.
Clypeodytes ignobilis Omer-Cooper, 1962; Clypeodytes inumbratus Guignot, 1936; Clypeodytes lautus Régimbart, 1895; Clypeodytes ovatus Omer-Cooper, 1931
Ponds.
Widespread to Western, Central and Eastern Africa.
Not previously recorded from St Lucia. Recorded at Western Shores and Eastern Shores in January/February 2015, during the course of this study.
Amarodytes octoguttatus caligosus Guignot, 1946; Bidessus gentilis Sharp, 1890; Uvarus monticola Guignot, 1957; Bidessus octoguttatus Régimbart, 1895; Bidessus ornatipennis Régimbart, 1899.
Ponds.
Widespread to Western and Eastern Africa.
Not previously recorded from St Lucia. Recorded at Eastern Shores in January/February 2015, during the course of this study.
Bidessus opacus Gschwendtner, 1935
Ponds.
Widespread to Central and Eastern Africa.
Not previously recorded from St Lucia. Recorded at Western Shores, Eastern Shores and False Bay in January/February 2015, during the course of this study.
Hydrovatus acuminatus furvus Guignot, 1950; Hydrovatus affinis Régimbart, 1895; Hydroporus badius Clark, 1863; Hydrovatus consanguineous Régimbart, 1880; Hydrovatus ferrugineus Zimmermann, 1919; Hydrovatus humilis Sharp, 1882; Hydroporus malaccae Clark, 1863; Hydrovatus obscurus Motschulsky, 1859; Hydrovatus obscurus Régimbart, 1895; Hydrovatus sordidus Sharp, 1882
Ponds in dense vegetation.
Widespread in Afrotropics, to Oriental Region.
Not previously recorded from St Lucia. Recorded at Western Shores, Eastern Shores and False Bay in January/February 2015, during the course of this study.
Hydrovatus dyscheres Guignot, 1955; Hydrovatus laticornis Régimbart, 1895.
Ponds in dense vegetation.
Widespread to Western, Central and Eastern Africa.
Ponds in dense vegetation.
KwaZulu-Natal and Zambia. Appears to be rare.
Not previously recorded from St Lucia. Recorded at Western Shores and Eastern Shores in January/February 2015, during the course of this study.
Ponds in dense vegetation.
Zimbabwe and Mozambique. New record for South Africa.
Ponds in dense vegetation.
Widespread in Southern Africa.
Hydrovatus abotti Guignot, 1959.
Ponds in dense vegetation.
Widespread to Central and Eastern Africa.
Hydrovatus crassus Guignot, 1958.
Ponds in dense vegetation.
Widespread to Western, Central and Eastern Africa.
Not previously recorded from St Lucia. Recorded at Eastern Shores in July 2014 and January/ February 2015, during the course of this study.
Hydrovatus adelphus Guignot, 1956; Hydrovatus straeleni Guignot, 1947.
Ponds in dense vegetation.
Widespread to Central and Eastern Africa.
Hydrovatus albertianus Guignot, 1959.
Ponds in dense vegetation.
Widespread to Western, Central and Eastern Africa.
Ponds in dense vegetation.
Zimbabwe to Eastern Africa. New record for South Africa.
Hydroporus barbarous Schaum, 1847; Hydroporus ferrugineus Lucas, 1846; Hydroporus hyphydroides Perris, 1864; Hydroporus inflatus Reiche, 1869; Hydroporus turgidus Erichson, 1843; Herophydrus umbrosus Zimmermann, 1926.
Ponds.
Widespread to Western, Central and Eastern Africa.
Not previously recorded from St Lucia. Recorded at Western Shores, Eastern Shores and False Bay in January/February 2015, during the course of this study.
Herophydrus cooperi Gschwendtner, 1938; Herophydrus ignoratus Gschwendtner, 1933; Herophydrus kalaharii Gschwendtner, 1935.
Ponds and stream pools. Eurytopic.
Widespread to Central and Eastern Africa.
Ponds.
Endemic to KwaZulu-Natal.
Not previously recorded from St Lucia. Recorded at Western Shores, Eastern Shores and False Bay in January/February 2015, during the course of this study.
Ponds.
Widespread to Western, Central and Eastern Africa.
Not previously recorded from St Lucia. Recorded at Western Shores, Eastern Shores and False Bay in November 2013, July 2014 and January/February 2015, during the course of this study.
Ponds.
Widespread to Western, Central and Eastern Africa.
Not previously recorded from St Lucia. Recorded at Western Shores and Eastern Shores in January/February 2015, during the course of this study.
Ponds.
Widespread to Central and Eastern Africa.
Hyphydrus circularis Régimbart, 1895; Hyphydrus lamottei Legros, 1958; Hyphydrus malawiensis Omer-Cooper, 1971; Hyphydrus nigeriensis Omer-Cooper, 1971; Hyphydrus pelates Guignot, 1953.
Ponds.
Widespread to Central and Eastern Africa.
Previously recorded by
Hyphydrus aethiopicus J. Balfour-Browne, 1944; Hyphydrus grossus Sharp, 1882.
Ponds.
Widespread to central and Eastern Africa.
Previously recorded by
Methles punctipennis Sharp, 1882; Methles umbrosus Gschwendtner, 1930.
Ponds in dense vegetation.
Widespread to Mediterranean basin and Middle East.
Not previously recorded from St Lucia. Recorded at Western Shores, Eastern Shores and False Bay in July 2014 and January/February 2015, during this study.
Ponds and small wetlands with dense vegetation. This beetle is either D. natalensis or an undescribed species. Omer-Cooper (1965) states that the type is in the Natural History Museum, London, but no specimens of this species are present in the collection (D.T. Bilton, pers. obs.). The male genitalia are close to Omer-Cooper’s figures of natalensis, but do differ. It is hoped that the identity of these specimens can be resolved by future studies of material named by Omer-Cooper.
Endemic to South-East Africa.
Not previously recorded from St Lucia. Recorded at Western Shores, Eastern Shores and False Bay in November 2013 and January/February 2015, during this study.
Uncertain. Appears to prefer dense vegetation.
Described from South Africa. Now known to be widespread, from Cameroon and Ethiopia through east Africa to the Cape (
Not previously recorded from St Lucia. Recorded at Western Shores, Eastern Shores and False Bay in January/February 2015, during the course of this study.
Ponds.
Widespread in Southern Central and Eastern Africa.
Holotype and some paratypes taken at light at St Lucia in 1975. Recorded at Western Shores, Eastern Shores and False Bay in July 2014 and January/February 2015, during the course of this study.
Ponds and other small waterbodies.
Widespread to Western, Central and Eastern Africa.
Not previously recorded from St Lucia. Recorded at Western Shores, Eastern Shores and False Bay in January/February 2015, during the course of this study.
Laccophilus monas Guignot, 1953.
Known from a range of habitats including a reservoir, river pools, river swamps, waterholes and dams (
Widespread from Sudan to South Africa and Namibia.
Not previously recorded from St Lucia. Recorded at Western Shores, Eastern Shores and False Bay in November 2013, July 2014 and January/February 2015, during the course of this study.