scholarly journals Landscape Evolution as a Diversification Driver in Freshwater Fishes

2022 ◽  
Vol 9 ◽  
Author(s):  
Pedro Val ◽  
Nathan J. Lyons ◽  
Nicole Gasparini ◽  
Jane K. Willenbring ◽  
James S. Albert

The exceptional concentration of vertebrate diversity in continental freshwaters has been termed the “freshwater fish paradox,” with > 15,000 fish species representing more than 20% of all vertebrate species compressed into tiny fractions of the Earth’s land surface area (<0.5%) or total aquatic habitat volume (<0.001%). This study asks if the fish species richness of the world’s river basins is explainable in terms of river captures using topographic metrics as proxies. The River Capture Hypothesis posits that drainage-network rearrangements have accelerated biotic diversification through their combined effects on dispersal, speciation, and extinction. Yet rates of river capture are poorly constrained at the basin scale worldwide. Here we assess correlations between fish species density (data for 14,953 obligate freshwater fish species) and basin-wide metrics of landscape evolution (data for 3,119 river basins), including: topography (elevation, average relief, slope, drainage area) and climate (average rainfall and air temperature). We assess the results in the context of both static landscapes (e.g., species-area and habitat heterogeneity relationships) and transient landscapes (e.g., river capture, tectonic activity, landscape disequilibrium). We also relax assumptions of functional neutrality of basins (tropical vs. extratropical, tectonically stable vs. active terrains). We found a disproportionate number of freshwater species in large, lowland river basins of tropical South America, Africa, and Southeast Asia, under predictable conditions of large geographic area, tropical climate, low topographic relief, and high habitat volume (i.e., high rainfall rates). However, our results show that these conditions are only necessary, but not fully sufficient, to explain the basins with the highest diversity. Basins with highest diversity are all located on tectonically stable regions, places where river capture is predicted to be most conducive to the formation of high fish species richness over evolutionary timescales. Our results are consistent with predictions of several landscape evolution models, including the River Capture Hypothesis, Mega Capture Hypothesis, and Intermediate Capture Rate Hypothesis, and support conclusions of numerical modeling studies indicating landscape transience as a mechanistic driver of net diversification in riverine and riparian organisms with widespread continental distributions.

2020 ◽  
Author(s):  
Simon Kaminskas

ABSTRACT Native freshwater fish of Australia have a diverse but largely undescribed endemic pathogen and parasite fauna. However, due to long-shared evolutionary histories and virulence/transmissibility trade-offs, effects of these endemic pathogens and parasites appear to be subtle: significant impacts are rarely observed and epizootics have not been recorded. In contrast, a number of alien pathogens and parasites are now established across southern Australia, causing manifestly harmful effects to native fish species and known or suspected epizootics in native fish populations. Undetected and/or undescribed alien viral pathogens are also suspected of being present. Alien pathogens and parasites were introduced to Australia with imports of live alien fish or their fertilised eggs. A review of the scientific and historical evidence indicates that they have had, and continue to have, greater impacts on native fish species than previously realised—especially for freshwater species. This review also documents a previously unknown, Murray-Darling-Basin-wide epizootic of Murray cod Maccullochella peelii in 1929–30, which may have contributed to strong declines in the related eastern freshwater cod Maccullochella ikei. A serious Chilodonella epizootic of M. peelii in 1982 is also examined. In addition, a possible role for alien viruses of the family Iridoviridae (Ranavirus and Megalocytivirus) in the general decline of the critically endangered silver perch Bidyanus bidyanus, and the rapid collapse of two specific native fish populations—upper Murrumbidgee River B. bidyanus and Shoalhaven River Macquarie perch Macquaria australasica—is suggested. It is argued that the severity of the impact of the virulent alien oomycete Saprolegnia parasitica, both historical and present day, has been underestimated. Finally, action is recommended against emerging new pathogen and parasite threats, and the extreme risk current alien fish importations pose in introducing them. These will further threaten already stressed native fish populations in southern Australia, particularly across the Murray-Darling Basin.


2021 ◽  
Vol 79 (2) ◽  
pp. 75-82
Author(s):  
Pero Tutman ◽  
Branko Glamuzina

Abstract Distributional range of freshwater blenny Salaria fluviatilis extends to the tributaries along the Mediterranean and Black seas. It is considered endangered in several Mediterranean European countries. Although previously mentioned in the lists of freshwater fish species, its presence has never before been confirmed in Bosnia and Herzegovina. Consequently, this has led to doubts about its distribution there. A sample specimen of freshwater blenny was obtained from the lower Neretva River (Adriatic Sea watershed) in Bosnia and Herzegovina in May 2020, representing the first reliable record of this species. Considering that this record confirms older reports, however, it seems that earlier surveys have failed to locate the fish. Knowledge of the composition of fish species in river basins and updating their list are among the important requirements for managing the biodiversity of each country, as well as water and fish resources.


2016 ◽  
Vol 14 (1) ◽  
Author(s):  
Juan Diego Martínez ◽  
Carlos Daniel Cadena ◽  
Mauricio Torres

Abstract Although temperature has far-reaching effects on fish biology, the thermal tolerance ranges of most freshwater fish species are unknown. This lack of information precludes forecasting responses to climatic change and does not allow for comparative analyses that may inform evolutionary and biogeographic studies. We used the critical thermal methodology to quantify acclimation capacity and thermal tolerance in the Neotropical freshwater species Poecilia caucana . For fish acclimated to 20˚C, 25ºC, and 28ºC, critical thermal minima (CTmin) were 12.52 ± 0.62ºC, 13.41 ± 0.56ºC and 14.24 ± 0.43ºC respectively, and critical thermal maxima (CTmax) were 38.43 ± 0.64ºC, 40.28 ± 0.92ºC and 41.57 ± 0.27ºC, respectively. Both CTmin and CTmax changed with acclimation temperatures, indicating that P. caucana was effectively acclimatable. Relative to values reported for other freshwater fish species, the acclimation capacity of P. caucana for CTmin was low, but it was average for CTmax. The data, together with similar work in other species, can be used in analyses focusing on broad ecological and evolutionary questions.


2012 ◽  
Vol 13 (2) ◽  
pp. 268 ◽  
Author(s):  
N. KOUTSIKOS ◽  
S. ZOGARIS ◽  
L. VARDAKAS ◽  
V. TACHOS ◽  
E. KALOGIANNI ◽  
...  

In this paper we supplement Greece’s recent annotated inventory of freshwater fishes per hydrographic basin with recent distributional data and taxa alteration information, based on field sampling and a literature review up to September 2011. We report on newly documented distributional records of 31 fish species plus one unidentified taxon, within 35 hydrographic river basin units in Greece. These new records include 14 native fish species, seven alien and 12 translocated. Translocated taxa are distinguished from aliens, in order to report species non-indigenous to a basin but native within the same ecoregion. Twelve hydrographic basin units are newly added to the roster of ichthyologically explored river basins following a previous basin-scale inventory method (the total is now 117). This review increases the number of Greece’s freshwater fish taxa to 167, since four new species are added to the list (Carassius langsdorfii, Neogobius fluviatilis, Telestes alfiensis, Millerigobius macrocephalus) and two are deleted (Salmo dentex, Barbus rebeli) due to taxonomic changes. Taxonomic changes will probably continue to alter the national list since phylogenetic research is ongoing on several taxa in many parts of the country


2018 ◽  
Author(s):  
Boris Leroy ◽  
Murilo S. Dias ◽  
Emilien Giraud ◽  
Bernard Hugueny ◽  
Céline Jézéquel ◽  
...  

AbstractAimTo define the major biogeographical regions and transition zones for freshwater fish species.TaxonStrictly freshwater species of actinopterygian fish (i.e., excluding marine and amphidromous fish families).MethodsWe based our bioregionalisation on a global database of freshwater fish species occurrences in drainage basins, which, after filtering, includes 11 295 species in 2 581 basins. On the basis of this dataset, we generated a bipartite (basin-species) network upon which we applied a hierarchical clustering algorithm (the Map Equation) to detect regions. We tested the robustness of regions with a sensitivity analysis. We identified transition zones between major regions with the participation coefficient, indicating the degree to which a basin has species from multiple regions.ResultsOur bioregionalisation scheme showed two major supercontinental regions (Old World and New World, 50% species of the world and 99.96% endemics each). Nested within these two supercontinental regions lie six major regions (Nearctic, Neotropical, Palearctic, Ethiopian, Sino-Oriental and Australian) with extremely high degrees of endemism (above 96% except for the Palearctic). Transition zones between regions were of limited extent compared to other groups of organisms. We identified numerous subregions with high diversity and endemism in tropical areas (e.g. Neotropical), and a few large subregions with low diversity and endemism at high latitudes (e.g. Palearctic).Main conclusionsOur results suggest that regions of freshwater fish species were shaped by events of vicariance and geodispersal which were similar to other groups, but with freshwater-specific processes of isolation that led to extremely high degrees of endemism (far exceeding endemism rates of other continental vertebrates), specific boundary locations, and limited extents of transition zones. The identified bioregions and transition zones of freshwater fish species reflect the strong isolation of freshwater fish faunas for the past 10 to 20 million years. The extremely high endemism and diversity of freshwater fish fauna raises many questions about the biogeographical consequences of current introductions and extinctions.


PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11952
Author(s):  
Rosa G. Beltrán-López ◽  
Alfonso A. González-Díaz ◽  
Miriam Soria-Barreto ◽  
Marco Antonio Garduño-Sánchez ◽  
Carmela Xochitla-Castrejón ◽  
...  

The endangered Chiapas killifish Tlaloc hildebrandi is an endemic freshwater species that lives in four subbasins of the Grijalva and Usumacinta basins, and one of the most geographically restricted species of the Produndulidae family. The species was originally described as endemic to springs in the high limestone plateau in San Cristóbal de Las Casas in the Río Amarillo subbasin (upper Grijalva basin). However, it was recently recorded in the Jataté and Tzaconejá subbasins in the upper Usumacinta basin, thereby expanding its known distribution range. The discovery of these populations is relevant not only for the conservation of the species but also for a better understanding of its evolutionary history. Currently, the scarce populations of T. hildebrandi, found in only a few localities in the Grijalva and Usumacinta basins, are fragmented and living under unfavorable conditions. Here, we analyzed three mitochondrial (mt-atp8&6 and mt-nd2) and one nuclear (nuc-s7) marker in order to assess the genetic diversity and population structure of T. hildebrandi. We found that, in comparison with other endangered freshwater fish species from Mexico, T. hildebrandi showed a lower level of genetic diversity (mt-nd2: h = 0.469, π = 0.0009; mt-atp8&6: h = 0.398, π = 0.001; and nuc-S7: h = 0.433, π = 0.001). Moreover, the analyzed populations exhibited a strong genetic structure in accordance with their geographic distribution, and can be placed into three genetic clusters: (1) Amarillo plus Chenhaló in the upper Grijalva basin, (2) Jataté, and (3) Tzaconejá, both in the upper Usumacinta basin. On the basis of our results, we propose the recognition of at least three evolutionarily significant units (ESUs) for the species and the urgent implementation of ex situ and in situ conservation and management efforts that consider the genetic background of the species.


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