Temperate urban mangrove forests : their ecological linkages with adjacent habitats

Estuarine habitats along the temperate south-eastern shores of Australia are generally made up of salt marsh, mangrove forests and seagrass beds. In urban areas these habitats have been progressively fragmented as a result of population increase and industrial expansion. Salt marshes in particular have been vulnerable to urban expansion and reclamation because of their close proximity to densely populated areas, while mangrove forests have been less often reclaimed because of frequent tidal inundation. The effect of reclamation of salt marshes on the biotic assemblages and functioning of mangrove forests with an adjacent salt marsh, park or bund wall was examined at nine separate locations on the Parramatta River, Sydney NSW. A mensurative approach was used to describe the patterns of distribution and abundance of macro fauna at several temporal and spatial scales. The implications for management are that salt marshes are an integral part of estuaries, and smaller patches of salt marsh are just as important as larger patches in maintaining the diversity of faunal assemblages and ecosystem functioning in mangrove forests in urban area

Saurodocus Yerman & Krapp-Schickel, 2008, gen. nov.

Saurodocus gen. nov. Type species. Saurodocus minimarenus sp. nov., by present designation. Diagnosis. Head anteroventral margin without notch or slit. Maxilla 1 inner plate triangular. Mandible palp first article not distally produced without distal tooth-shaped prolongation, article 2 longer than article 3. Gnathopod 1 coxa anteroventral corner not produced. Pereopod 4 coxa without posteroventral lobe. Epimeral plates lacking serrations on posterior margin. Uropod 3 inner ramus subequal to outer ramus; outer ramus about twice as long as peduncle. Telson deeply cleft, lobes truncated with apical cusps and short apical robust setae. Etymology. A combination of the Greek word Sauros, meaning lizard, alluding to the type locality, with the stem – docus from Ceradocus. Included species. Saurodocus hobbit sp. nov. and S. minimarenus sp. nov. Remarks. Saurodocus belongs to the Ceradocus group — a group of genera within the Melitidae allied to Ceradocus Costa, 1853, united by a widened triangular inner plate on maxilla 2 and setation on the inner margin of the inner plates of both maxillae. The Ceradocus group will be treated in detail by Krapp-Schickel (in press). Saurodocus, however, appears to be an isolated genus within the group. This may be a result of independent adaptations to an interstitial lifestyle which has not been documented for other genera. Saurodocus is different from other genera in the group owing to a unique set of characters: article 3 of antenna 2 is globular and the anteroventral corner of coxa 1 is not produced. Saurodocus is presently known only from tropical Australian waters.Published as part of Yerman, Michelle N. & Krapp-Schickel, Traudl, 2008, A new genus and two new species of Saurodocus (Crustacea: Amphipoda: Melitidae) from Lizard Island, Queensland, Australia, pp. 60-66 in Zootaxa 1820 on page 61, DOI: 10.5281/zenodo.18300

Saurodocus minimarenus Yerman & Krapp-Schickel, 2008, sp. nov.

<i>Saurodocus minimarenus</i> sp. nov. <p>(Figs 1, 2)</p> <p> <b>Type material.</b> Holotype: AM P77560, female, 1.2 mm, on slide, reef crest off Coconut Beach, Lizard Island, 14°41.037’S, 145°28.282’E, patches of coarse coral sand between reef, core, 2.6 m, M. Yerman, 23 February 2005, stn QLD 1620.</p> <p> <b>Etymology.</b> A combination of the Latin words <i>minimus,</i> meaning small, and <i>arena,</i> meaning sand. These words are combined to give name to a ‘little sand dweller’.</p> <p> <b>Description of holotype. Head</b> with anteroventral corner rounded; without notch or slit; eyes ovate to reniform. <i>Antenna 1</i> longer than antenna 2, peduncle rather strong, peduncular article 1 longer than article 2, without robust setae along posterior margin; flagellum with 8 articles; accessory flagellum minute, with 2 articles. <i>Antenna 2</i> peduncular article 2 cone gland not reaching to end of peduncular article 3; article 3 globular; article 4 subequal to longer than article 5; flagellum with 5 articles. <i>Mandible palp</i> inner margin of article 1 weakly produced distally, article 2 longer than article 3, article 3 longer than article 1, with 2 lateral setae, 3 smooth distal setae and many shorter setae along the surface. <i>Maxilla 1</i> inner plate with 3 distal setae. <i>Maxilla 2</i> inner plate with marginal setae, without oblique setal row. <i>Maxilliped</i> inner plate not reaching basis of outer plate, which is about the same length.</p> <p> <b>Pereon</b> <i>Gnathopod 1</i> coxa anteroventral corner not produced, anterior margin convex; carpus 0.6 x length of propodus, triangular, shorter than propodus; palm nearly transverse and defined by posterodistal corner. <i>Gnathopod 2</i> propodus similar to gnathopod 1, but narrower and lacking palmar corner, anterior and posterior margins with setae; carpus triangular, shorter than propodus.</p> <p> <i>Pereopods 3–7</i> dactyli without anterodistal spine. <i>Pereopods 5–7</i> slender, with few short setae, basis posterior margin smooth.</p> <p> <b>Pleon</b> <i>Pleonite 1</i> dorsally smooth. <i>Pleonite 2</i> with dorsal spine. <i>Pleonite 3</i> dorsally smooth. <i>Epimeron 1</i> posteroventral corner with small acute or subacute spine. <i>Epimeron 2</i> posteroventral corner acute. <i>Epimeron 3</i> posteroventral margin distally with some small teeth. <i>Urosomite 1</i> with long dorsal spine. <i>Urosomite 2</i> posterior margin smooth. <i>Urosomite 3</i> without dorsal setae. <i>Uropod 1</i> peduncle longer than rami. <i>Uropod 2</i> peduncle longer than rami. <i>Uropod 3</i> rami 6.5 x longer than broad, distally acute or subacute, lanceolate, about double the length of the peduncle. <i>Telson</i> quadrangular, deeply cleft; longer than broad with 2 short, subapical robust setae on each lobe, no lateral setation.</p> <p> <b>Habitat.</b> Living in coarse coral sand on coral reef at 2.6 m. Probably interstitial.</p> <p> <b>Distribution.</b> <i>Australia.</i> Queensland: Lizard Island.</p> <p> <b>Remarks.</b> <i>Saurodocus minimarenus</i> differs from <i>S. hobbit</i> in the following features: maxilla 2 does not have an oblique setal row (present in <i>S. hobbit</i>); the gnathopod 2 propodus is shorter than that of <i>S. hobbit</i>; the pleon bears dorsal spines (smooth in <i>S. hobbit</i>); the posteroventral corner of epimeron 1 has a small acute spine (lacking in <i>S. hobbit</i>), and the posteroventral corner of epimeron 3 is slightly serrated (smooth in <i>S. hobbit</i>).</p>Published as part of <i>Yerman, Michelle N. & Krapp-Schickel, Traudl, 2008, A new genus and two new species of Saurodocus (Crustacea: Amphipoda: Melitidae) from Lizard Island, Queensland, Australia, pp. 60-66 in Zootaxa 1820</i> on pages 61-64, DOI: <a href="http://zenodo.org/record/183004">10.5281/zenodo.183004</a&gt

Saurodocus hobbit Yerman & Krapp-Schickel, 2008, sp. nov.

Saurodocus hobbit sp. nov. (Fig. 3) Type material. Holotype: AM P 77695, female, 2.2 mm ovigerous with one large egg, on slide, Mermaid Cove, Lizard Island, 14 ° 38.90 ' S, 145 ° 27.26 ’E, swash/subtidal, protected beach with patch reefs offshore, coarse coral sand with pieces of coral, 0.5 –1.0 m, S.E. LeCroy, 2 July 2001, stn SEL/LZI- 1 - 1. Paratype: AM P77696, 1 incomplete female, approximately 1.8 mm, type locality. Etymology. Named after the fictional small people of "halflings" in the fantasy novels written by J.R.R. Tolkien in the traditions of a fairy tale; used as a noun in apposition. Description of holotype. Head with anteroventral corner rounded; without notch or slit; eyes ovate to reniform. Antenna 1 without robust setae along posterior margin, peduncle strong, flagellum lost, therefore accessory flagellum unknown. Antenna 2 peduncular article 2 cone gland not reaching to end of peduncular article 3; article 3 globular, article 4 subequal to or longer than article 5. Mandible palp inner margin of article 1 without tooth-shaped prolongation; article 2 longer than article 3, article 3 longer than article 1, slim (subovoid with straight posterior margin), with 3 pectinate setae laterally, 3 smooth setae distally. Maxilla 1 inner plate subtriangular, as wide as high, with 6 setae on inner margin. Maxilla 2 with oblique setal row. Pereon Gnathopod 1 coxa anteroventral corner not produced; carpus 0.9 x length of propodus, propodus shorter than coxa, hind margin rounded, palm acute, defined by posterodistal corner. Gnathopod 2 dactylus inner margin with 2 incisions, propodus similar to gnathopod 1, but narrower, on anterior and posterior margin beset with setae; carpus triangular, shorter than propodus. Pereopods 3–7 dactyli without anterodistal spine. Pereopods 5–7 slender, with few short setae, basis posterior margin smooth. Pleon Pleonites 1–3 dorsally smooth. Epimeron 1 posteroventral corner narrowly rounded or subquadrate. Epimeron 2 posteroventral corner smooth with acute posterodistal spine. Epimeron 3 posteroventral margin smooth. Urosomite 1 without spines or gape. Urosomite 2 posterior margin smooth. Urosomite 3 without dorsal setae. Uropod 1 peduncle longer than rami. Uropod 2 peduncle subequal to rami. Uropod 3 rami 7 x longer than broad, lanceolate, distally acute, about double the length of the peduncle. Telson quadrangular, deeply cleft; longer than broad with 2 or 3 short, subapical robust setae on each lobe, no lateral setation found. Habitat. Marine; living in coarse coral sand with pieces of coral at 0.5–1 m; probably interstitial. Distribution. Australia. Queensland: Lizard Island. Remarks. The tiny holotype was carrying one large egg, and was undoubtedly adult.Published as part of Yerman, Michelle N. & Krapp-Schickel, Traudl, 2008, A new genus and two new species of Saurodocus (Crustacea: Amphipoda: Melitidae) from Lizard Island, Queensland, Australia, pp. 60-66 in Zootaxa 1820 on page 64, DOI: 10.5281/zenodo.18300

Landscape issues for the macrofauna in temperate urban mangrove forests

Estuarine habitats along Australia's temperate shores generally comprise saltmarsh, mangrove forests and seagrass habitats. In urban areas these habitats have been progressively fragmented due to human population increase and industrial expansion. Saltmarshes are particularly vulnerable to urban expansion because of their close proximity to densely populated areas. However, there is limited understanding of what effect the reclamation of saltmarsh habitats has on the macrofauna in adjacent mangrove forests.We examined the importance of saltmarshes on adjacent mangrove forests at nine locations on the Parramatta River, Sydney, New South Wales.The habitats examined consisted of mangrove forests with and without an adjacent saltmarsh habitat.The diversity and abundance of macrofauna were sampled during spring 1999 and summer 2000. Overall, there was a trend for the diversity of macrofauna to be greater in mangrove forests with an adjacent saltmarsh compared to those with an adjacent park or bund wall. Macrofaunal diversity was 36% lower in mangrove forests without adjacent saltmarsh habitats. In addition, the diversity of macrofauna in mangrove forests adjacent to a saltmarsh showed the least variability, while those adjacent to a bund wall showed the greatest variability. This study has shown that the diversity and abundance of macrofauna in urban mangrove forests was correlated with the adjacent habitat, thus it is important to conserve remnant patches of saltmarsh in our urban environment

With a Little Help from My Friends: Group Orientation by Larvae of a Coral Reef Fish.

Theory and some empirical evidence suggest that groups of animals orient better than isolated individuals. We present the first test of this hypothesis for pelagic marine larvae, at the stage of settlement, when orientation is critical to find a habitat. We compare the in situ behaviour of individuals and groups of 10-12 Chromis atripectoralis (reef fish of the family Pomacentridae), off Lizard Island, Great Barrier Reef. Larvae are observed by divers or with a drifting image recording device. With both methods, groups orient cardinally while isolated individuals do not display significant orientation. Groups also swim on a 15% straighter course (i.e. are better at keeping a bearing) and 7% faster than individuals. A body of observations collected in this study suggest that enhanced group orientation emerges from simple group dynamics rather than from the presence of more skilful leaders

Orientation of fish larvae in situ is consistent among locations, years and methods, but varies with time of day

Understanding larval dispersal requires knowledge of whether larvae in situ have orientated swimming, and how this varies temporally and spatially. Orientation of >300 settlement-stage larvae of Chromis atripectoralis (Pomacentridae) measured over 1998-2008 by divers near Lizard Island, Great Barrier Reef was consistent. All 10 data sets had southerly orientation at all locations; 94% of larvae swam directionally. Median bearings east and west of Lizard Island were 166 degrees and 170 degrees, respectively. Orientation precision was significantly higher under sunny than cloudy skies. Similar mean bearings were obtained in 2008 with more than 125 larvae observed in a drifting in situ chamber (DISC). Orientation varied with time of day. In sunny conditions, precision was weakly, significantly correlated with time of day, but not solar elevation; however, a greater proportion of larvae was significantly directional at low (50 degrees) solar elevation. Mean bearing and time of day were weakly, but significantly correlated. Bearings changed from SE during most of the day to SSW in the late afternoon, with distribution of bearings significantly different. Location-independent but diurnally-dependent orientation implies that larvae used celestial cues for orientation. Of 91 Pomacentrus lepidogenys larvae that were followed by divers, 89% swam directionally, but orientation differed among locations and years. DISC results with 20 larvae were similar. The similarity of orientation returned by different methods used on 2 fish species corroborates previous results using diver following. Both methods are useful for the study of larval-fish orientation in situ: each has advantages and limitations, and their use is complementary

Distribution of within-run mean bearings for individuals or groups (columns) followed or in the DISC (rows).

<p>Each dot represents one observation run. When orientation is significant (<i>p</i><0.05, in the corner of panels), the radius in the centre is in the mean direction of orientation and its length represents the precision of orientation (across-runs <i>r</i>). Only groups display significant orientation, towards the south.</p