Aquatic insects in a sea of desert: population genetic structure is shaped by limited dispersal in a naturally fragmented landscape

AbstractUnderstanding population genetic structure can help us to infer dispersal patterns, predict population resilience and design effective management strategies. For sessile species with limited dispersal, this is especially pertinent because genetic diversity and connectivity are key aspects of their resilience to environmental stressors. Here, we describe the population structure of Ircinia campana, a common Caribbean sponge subject to mass mortalities and disease. Microsatellites were used to genotype 440 individuals from 19 sites throughout the Greater Caribbean. We found strong genetic structure across the region, and significant isolation by distance across the Lesser Antilles, highlighting the influence of limited larval dispersal. We also observed spatial genetic structure patterns congruent with oceanography. This includes evidence of connectivity between sponges in the Florida Keys and the southeast coast of the United States (>700 km away) where the oceanographic environment is dominated by the strong Florida Current. Conversely, the population in southern Belize was strongly differentiated from all other sites, consistent with the presence of dispersal-limiting oceanographic features, including the Gulf of Honduras gyre. At smaller spatial scales (<100 km), sites showed heterogeneous patterns of low-level but significant genetic differentiation (chaotic genetic patchiness), indicative of temporal variability in recruitment or local selective pressures. Genetic diversity was similar across sites, but there was evidence of a genetic bottleneck at one site in Florida where past mass mortalities have occurred. These findings underscore the relationship between regional oceanography and weak larval dispersal in explaining population genetic patterns, and could inform conservation management of the species.

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Population genetic structure inMyrtus communisL. in a chronically fragmented landscape in the Mediterranean: can gene flow counteract habitat perturbation?

Plant Biology ◽

10.1111/j.1438-8677.2008.00121.x ◽

2009 ◽

Vol 11 (3) ◽

pp. 442-453 ◽

Cited By ~ 24

Author(s):

R. G. Albaladejo ◽

L. F. Carrillo ◽

A. Aparicio ◽

J. F. Fernández-Manjarrés ◽

J. P. González-Varo

Keyword(s):

Gene Flow ◽

Genetic Structure ◽

Population Genetic Structure ◽

Population Genetic ◽

Fragmented Landscape ◽

The Mediterranean

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Contrasting population genetic structure of two widespread aquatic insects in the Chilean high-slope rivers

Marine and Freshwater Research ◽

10.1071/mf10105 ◽

2011 ◽

Vol 62 (1) ◽

pp. 1 ◽

Cited By ~ 19

Author(s):

M. C. Sabando ◽

I. Vila ◽

R. Peñaloza ◽

D. Véliz

Keyword(s):

Population Structure ◽

Genetic Structure ◽

Population Genetic Structure ◽

Aquatic Insects ◽

Population Genetic ◽

Nuclear Markers ◽

Widespread Species ◽

Central Chile ◽

Physical Barriers ◽

Three Rivers

Dispersal and many other factors affect population genetic structure. In central Chile, rivers are characterised by strong currents and transverse mountain chains, which impose physical barriers to the populations that inhabit them. The objective of the present study was to study the population genetic structure of two widespread species of aquatic insects, the caddisfly Smicridea annulicornis and the mayfly Andesiops torrens, in three isolated rivers, Choapa, Maipo and Maule. The analysis of population structure, using both mtDNA (cytochrome C oxidase subunit 1, COI) and nuclear markers (amplified fragment length polymorphism, AFLP), considered samples from within and among rivers. In S. annulicornis, we found differentiation within and among rivers, indicating a low dispersal among the study area. Populations of A. torrens shared haplotypes in all three rivers and no differences were found among rivers, indicating that this species probably has more dispersal potential than does S. annulicornis; however, significant differences were observed within rivers. Our results indicate that the transverse mountain chains are not a barrier for A. torrens, which can disperse among rivers. Within rivers, the population structure suggests that these species are probably adapted to avoid drift because of the torrential character of these Chilean rivers.

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Prawn parade: notes on Macrobrachium australiense Holthius, 1950 climbing vertical concrete overflow steps at Gold Creek Reservoir, Queensland

Marine and Freshwater Research ◽

10.1071/mf18362 ◽

2019 ◽

Vol 70 (10) ◽

pp. 1480

Author(s):

Janne J. Torkkola ◽

Donna W. Hemsley

Keyword(s):

Genetic Structure ◽

Population Genetic Structure ◽

Population Genetic ◽

Current Source ◽

Dispersal Ability ◽

Broad Distribution ◽

Current Stimulus ◽

Limited Dispersal ◽

Australian Freshwater

The freshwater palaemonid shrimp, Macrobrachium australiense, is widespread throughout eastern Australian freshwater catchments. Population genetic structure suggests limited dispersal ability, despite its broad distribution, with one case of observed springtime climbing migration at Queensland’s Dawson Weir. Here, we describe a second record of observed climbing migration, from Queensland’s Gold Creek Reservoir in August 2018. We discuss the likely causes of these migrations, agreeing with Lee and Fielder’s (1979) assessment of intermittent current stimulus and collective rheotactic response leading to mass climbing towards current source.

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