scholarly journals Sampling patchy distributions:comparison of sampling designs in rocky intertidal habitats

2000 ◽  
Vol 196 ◽  
pp. 1-14 ◽  
Author(s):  
AW Miller ◽  
RF Ambrose
Keyword(s):  
Rocky Intertidal ◽  
Intertidal Habitats

scholarly journals Cryptic biodiversity and phylogeographic patterns of Seychellois Ligia isopods

2017 ◽  
Author(s):  
Carlos A Santamaria ◽  
Joanna K Bluemel ◽  
Nancy Bunbury ◽  
Melinda Curran
Keyword(s):  
Cryptic Species ◽  
Western Indian Ocean ◽  
Rocky Intertidal ◽  
Biological Traits ◽  
Cryptic Diversity ◽  
Species Complexes ◽  
Cryptic Species Complex ◽  
Cryptic Biodiversity ◽  
Intertidal Habitats

Ligia isopods are conspicuous inhabitants of rocky intertidal habitats exhibiting several biological traits that severely limit their dispersal potential. Their presence in patchy habitats and low vagility may lead to long term isolation, allopatric isolation and possible cryptic speciation. Indeed, various species of Ligia have been suggested to represent instead cryptic species complexes. Past studies; however, have largely focused in Eastern Pacific and Atlantic species of Ligia, leaving in doubt whether cryptic diversity occurs in other highly biodiverse areas. The Seychelles consists of 115 islands of different ages and geological origins spread across the western Indian Ocean. They are well known for their rich biodiversity with recent reports of cryptic species in terrestrial Seychellois organisms. Despite these studies, it is unclear whether coastal invertebrates from the Seychelles harbor any cryptic diversity. In this study, we examined patterns of genetic diversity and isolation within Ligia isopods across the Seychelles archipelago by characterizing individuals from locations across both inner and outer islands of the Seychelles using mitochondrial and nuclear markers. We report the presence of highly divergent lineages of independent origin. At Aldabra Atoll, we uncovered a lineage closely related to the Ligia vitiensis cryptic species complex. Within the inner islands of Cousine, Silhouette, and Mahé we detected the presence of two moderately divergent and geographically disjunct lineages most closely related to Ligia dentipes. Our findings suggest that the Seychelles may harbor at least three novel species of Ligia in need of description and that these species may have originated independently.

scholarly journals Parasite burden in decapod crustaceans from the central coast of Chile: is there any association with the relationship with definitive host abundances?

2017 ◽  
Vol 43 (4) ◽  
pp. 726-738
Author(s):  
Natalia Leiva ◽  
Mario George-Nascimento ◽  
Gabriela Muñoz
Keyword(s):  
Definitive Host ◽  
Parasite Burden ◽  
Life Cycles ◽  
Rocky Intertidal ◽  
Decapod Crustaceans ◽  
Intermediate Hosts ◽  
Rocky Intertidal Zone ◽  
The Family ◽  
Intertidal Habitats ◽  
The Relationship

Crustaceans play an important role in parasite life cycles, serving as second intermediate hosts. However, there are scarce parasitological studies in crustaceans from the rocky intertidal habitats, in Chile and around de world. In this study we aimed to record the parasites in decapod crustaceans, compare their parasitic loads between localities and relate them with the abundance of the definitive hosts (fishes and birds). Between July and September 2013, 409 crustacean specimens, corresponding to 16 species, were collected from the rocky intertidal zone of two localities of central Chile (33°S), Las Cruces and Montemar. Of out the sample, 65.5% was parasitized; counting 2,410 metacercariae and 18 nematodes. One group of these metacercariae belonged to the family Opecoelidae; while others corresponded to the family Microphallidae. Nematodes belonged to the family Cystidicolidae. The highest prevalence and abundance of opecoelids were in P. violaceus (96.9%, 13.59 ± 17.50 parasites/crustacean), microphallids were mostly recorded in the crab Petrolisthes tuberculosus (42.3%, 11.08 ± 4.8 parasites/crustacean), while cystidicolids were less prevalent and abundant than digenean at both localities. Parasite loads was affected by body size, locality and species of crustacean hosts. No association was found between parasite loads in these intermediate hosts and the abundance of definitive hosts. The low relationships between parasite loads and host abundances may be due to several reasons, such as a wide trophic spectrum and great capacity of movement, which would not contribute to the parasite transmission and the direct relationship with the definitive host abundances.

scholarly journals Facilitation by macroalgae [full paper published in Algae 32 (1): 41-46, 2017]

2017 ◽  
Author(s):  
Ricardo Augusto Scrosati
Keyword(s):  
Benthic Communities ◽  
Algal Species ◽  
High Stress ◽  
Canopy Cover ◽  
Community Level ◽  
Rocky Intertidal ◽  
Marine System ◽  
Sources Of Variation ◽  
Intertidal Habitats ◽  
High Elevations

In rocky intertidal habitats, abiotic stress due to desiccation and thermal extremes increases with elevation because of tides. A study in Atlantic Canada showed that, at low elevations where conditions are benign due to the brief low tides, fucoid algal canopies (Ascophyllum nodosum and Fucus spp.) do not affect the structure of benthic communities. However, at middle and high elevations, where low tides last longer, fucoid canopies limit abiotic extremes and increase the richness (number of invertebrate and algal species, except fucoids) of benthic communities. Using the data from that study, this paper compares the intensity of facilitation and its importance (relative to all other sources of variation in richness) between middle and high elevations, which represent intermediate and high stress, respectively. Facilitation intensity was calculated as the percent increase in benthic richness between quadrats with low and high canopy cover, while the importance of facilitation was calculated as the percentage of variation in richness explained by canopy cover. Data for 689 quadrats spanning 350 km of coastline were used. Both the intensity and importance of facilitation were greater at middle elevations than at high elevations. As canopies do not affect benthic communities at low elevations, this study suggests that the facilitation-stress relationship at the community level is unimodal for this marine system. Such a pattern was found for some terrestrial systems dominated by canopy-forming plants. Thus, it might be ubiquitous in nature and, as further studies refine it, it might help to predict community-level facilitation depending on environmental stress.

scholarly journals Barnacle recruit density and size increase from high to middle intertidal elevations in wave-exposed habitats on the Atlantic coast of Nova Scotia

2019 ◽  
Author(s):  
Ricardo A Scrosati
Keyword(s):  
Nova Scotia ◽  
Interspecific Interactions ◽  
Atlantic Coast ◽  
Rocky Intertidal ◽  
Ne Atlantic ◽  
Relevant Role ◽  
Ne Pacific ◽  
Intertidal Habitats ◽  
High Elevations ◽  
Intertidal Environments

Barnacle recruitment is often studied in rocky intertidal habitats due to the relevant role that barnacles can play in intertidal communities. In 2014, barnacle (Semibalanus balanoides) recruitment was measured at high elevations in wave-exposed intertidal habitats on the NW Atlantic coast in Nova Scotia, Canada. Values were considerably lower than previously reported for middle elevations in wave-exposed intertidal habitats on the NE Atlantic and NE Pacific coasts. To determine if such differences in recruitment may have resulted from elevation influences, I did a field experiment in 2019 in wave-exposed intertidal habitats in Nova Scotia to test the hypothesis that recruitment is higher at middle than at high elevations, based on known environmental differences between both elevation zones. Based on data from three locations spanning 158 km of the Nova Scotia coast, barnacle recruitment was, on average, nearly 200 % higher (and recruits were larger) at middle than at high elevations. However, even with this increase, barnacle recruitment on this NW Atlantic coast is still lower than for comparable habitats on the NE Atlantic and NE Pacific coasts, and also lower than previously reported for wave-exposed locations farther south on the NW Atlantic coast, in Maine, USA. Therefore, barnacle recruitment in wave-exposed intertidal environments in Nova Scotia appears to be only moderate relative to other shores. This difference in the supply of barnacle recruits might influence the intensity of interspecific interactions involving barnacles.

scholarly journals Differential recolonization of Atlantic intertidal habitats after disturbance reveals potential bottom-up community regulation

F1000Research ◽  
2014 ◽  
Vol 3 ◽  
pp. 247 ◽  
Author(s):  
Willy Petzold ◽  
Ricardo A. Scrosati
Keyword(s):  
Atlantic Coast ◽  
Early Summer ◽  
Rocky Intertidal ◽  
Intertidal Communities ◽  
Bottom Up ◽  
Community Regulation ◽  
Intertidal Habitats ◽  
Underlying Mechanisms ◽  
Main Food Source ◽  
Coastal Phytoplankton

In the spring of 2014, abundant sea ice that drifted out of the Gulf of St. Lawrence caused extensive disturbance in rocky intertidal habitats on the northern Atlantic coast of mainland Nova Scotia, Canada. To monitor recovery of intertidal communities, we surveyed two wave-exposed locations in the early summer of 2014. Barnacle recruitment and the abundance of predatory dogwhelks were low at one location (Tor Bay Provincial Park) but more than 20 times higher at the other location (Whitehead). Satellite data indicated that the abundance of coastal phytoplankton (the main food source for barnacle larvae) was consistently higher at Whitehead just before the barnacle recruitment season, when barnacle larvae were in the water column. These observations suggest bottom-up forcing of intertidal communities. The underlying mechanisms and their intensity along the NW Atlantic coast could be investigated through studies done at local and regional scales.

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