Identification Of Management Units Research Articles

Major Cuban Green Turtle Rookeries: Identification of Management Units and Their Genetic Relationships with Other Greater Caribbean Populations

Genetic monitoring of highly migratory endangered species is fundamental for effective management, particularly when they are shared internationally, and their populations need to be identified. A prime example is the green turtle, Chelonia mydas, whose genetic structure has been extensively studied in the Western Atlantic. Nevertheless, the identification of Cuban management units has remained uncertain, despite representing regionally significant nesting assemblages and occurring within a strategically central position. Compared to previous work, the current study used 800 bp mtDNA control region sequences and larger sample sizes (n = 189 from four nesting sites in SW Cuba). Of the 23 resolved haplotypes, nine were novel, fourteen were reported in Cuba for the first time, and eleven were endemic. Even though the distribution of nesting grounds barely spans 300 km, three management units were identified: Guanahacabibes-San Felipe (GUCB; with most of the endemic haplotypes), Isla de la Juventud (IJCB; with a predominance of haplotype CM-A13.1), and Cayo Largo (CLCB; with a haplotype profile closely related to Southern Caribbean rookeries). We discuss how the geographic distribution of mtDNA variation has likely been shaped by local and regional oceanic current patterns or derived from formerly hyperabundant regional populations. Genetic characterization of Cuban management units represents a significant contribution, filling critical knowledge gaps that have hampered the comprehensive mixed-stock analyses required to guide effective regional conservation strategies.

Identification of management units in threatened populations of Arnica mallotopus Makino (Asteraceae) using novel EST-SSR markers.

Arnica mallotopus is a perennial herb endemic to the snowy regions of Japan. At the southern edge of its distribution, in Kyoto Prefecture, overgrazing by sika deer and decreased snowfall have resulted in the rapid decline of A. mallotopus populations. Therefore, there is an urgent need for a conservation genetic analysis of the remaining local populations. In this study, we first developed 13 EST-SSR markers to evaluate genetic variation in A. mallotopus. The average number of alleles per locus was 5.33. Genetic analysis using these markers showed that the investigated samples were classified into two groups corresponding to landscape structure. One group isolated from a tributary of the Yura River showed a strong population bottleneck signal, likely resulting from founder effects and subsequent drifts. On the other hand, the genetic diversity of the second group in the main distribution along the Yura River was higher and less inbred. Overall, our assessment suggested recognizing the two genetic groups as management units in conservation programs for the threatened populations.

Conservation of migratory fishes in the Amazon basin

Abstract The Amazon basin hosts the Earth's highest diversity of freshwater fish. Fish species have adapted to the basin's size and seasonal dynamics by displaying a broad range of migratory behaviour, but they are under increasing threats; however, no study to date has assessed threats and conservation of Amazonian migratory fishes. Here, the available knowledge on the diversity of migratory behaviour in Amazonian fishes is synthesized, including the geographical scales at which they occur, their drivers and timing, and life stage at which they are performed. Migratory fishes are integral components of Amazonian society. They contribute about 93% (range 77–99%) of the fisheries landings in the basin, amounting to ~US$436 million annually. These valuable fish populations are mainly threatened by growing trends of overexploitation, deforestation, climate change, and hydroelectric dam development. Most Amazonian migratory fish have key ecological roles as apex predators, ecological engineers, or seed‐dispersal species. Reducing their population sizes could induce cascading effects with implications for ecosystem stability and associated services. Conserving Amazonian migratory fishes requires a broad portfolio of research, management, and conservation actions, within an ecosystem‐based management framework at the basin scale. This would require trans‐frontier coordination and recognition of the crucial importance of freshwater ecosystems and their connectivity. Existing areas where fishing is allowed could be coupled with a chain of freshwater protected areas. Management of commercial and subsistence species also needs fisheries activities to be monitored in the Amazonian cities and in the floodplain communities to allow assessments of the status of target species, and the identification of management units or stocks. Ensuring that existing and future fisheries management rules are effective implies the voluntary participation of fishers, which can be achieved by increasing the effectiveness and coverage of adaptive community‐based management schemes.

Review of genetic monitoring programs of wildlife species in Serbia

Genetic monitoring, as one of the main aspects in long-term population monitoring, has a crucial role in establishing an effective management strategy and biological conservation of wildlife. Determination and monitoring of genetic variability as well as identification of management units, represents the best estimator of natural population potential for adaptation and survival. Here we present a comparative overview of data obtained through genetic monitoring of three wildlife species in Serbia - brown hares, wild boars and grey wolves. First determination of genetic variability in brown hares from Serbia recommended an optimal three-year monitoring period for this species and continual genetic monitoring has revealed maintenance of moderate genetic diversity over a twenty-year period. Furthermore, it is suggested that future genetic monitoring should encompass more informative molecular markers, such as those linked to adaptive traits. Microsatellite molecular markers have provided much of the required information about the wild boar population. The wild boar is one of the most important game species and is crucial to estimate adequate management measures in order to preserve genetic variability, but also, to prevent possible territorial expansion of the species. Panel of 18 microsatellite loci proved to be very informative when it comes to the grey wolf population. Serbian wolf population is relatively stable for now, but it is very important to maintain appropriate genetic monitoring to preserve this valuable reservoir of genetic variability. The results, obtained through genetic monitoring of these three species in Serbia, support integration of genetic information with other traditional methods for hunting management strategy in order to provide a long-term sustainability.

Polymorphic microsatellite markers for the endangered fish, the slender shiner Pseudopungtungia tenuicorpa and cross-species amplification across five related species.

The slender shiner Pseudopungtungia tenuicorpa (Cypriniformes; Cyprinidae; Gobioninae) is an endangered freshwater fish species endemic to Korea. The current strategies for its conservation involve the study of population genetic characters and identification of management units. These strategies require suitable molecular markers to study genetic diversity and genetic structure. Here, we developed nine polymorphic microsatellite markers for P. tenuicorpa for the first time by applying an enrichment method from a size-selected genomic library. The developed microsatellite markers produced a total of 101 alleles (average 11.2). The observed and expected heterozygosities averaged 0.805 and 0.835, respectively. Among the nine identified markers, five markers showed successful amplification across five related Korean Gobioninae species. Thus, the microsatellite markers developed in this study will be useful to establish conservation strategies for both P. tenuicorpa and other related species.

Three-dimensional post-glacial expansion and diversification of an exploited oceanic fish.

Vertical divergence in marine organisms is being increasingly documented, yet much remains to be carried out to understand the role of depth in the context of phylogeographic reconstruction and the identification of management units. An ideal study system to address this issue is the beaked redfish, Sebastes mentella – one of four species of ‘redfish’ occurring in the North Atlantic – which is known for a widely distributed ‘shallow‐pelagic’ oceanic type inhabiting waters between 250 and 550 m, and a more localized ‘deep‐pelagic’ population dwelling between 550 and 800 m, in the oceanic habitat of the Irminger Sea. Here, we investigate the extent of population structure in relation to both depth and geographic spread of oceanic beaked redfish throughout most of its distribution range. By sequencing the mitochondrial control region of 261 redfish collected over a decadal interval, and combining 160 rhodopsin coding nuclear sequences and previously genotyped microsatellite data, we map the existence of two strongly divergent evolutionary lineages with significantly different distribution patterns and historical demography, and whose genetic variance is mostly explained by depth. Combined genetic data, analysed via independent approaches, are consistent with a Late Pleistocene lineage split, where segregation by depth probably resulted from the interplay of climatic and oceanographic processes with life history and behavioural traits. The ongoing process of diversification in North Atlantic S. mentella may serve as an ‘hourglass’ to understand speciation and adaptive radiation in Sebastes and in other marine taxa distributed across a depth gradient.

Conservation genetics of tilapias: Seeking to define appropriate units for management

Tilapias comprise 112 species and subspecies of cichlid fishes of the genera Oreochromis, Sarotherodon, and Tilapia. Because of the importance of tilapias to aquatic ecosystem structure and function, fisheries, and aquaculture, it is critically important to conserve wild genetic resources. Of the 112 recognized tilapia taxa, 41 are regarded as imperiled. In order to manage adaptively important genetic variation in tilapias, we need to recognize and define biologically appropriate units of conservation. An evolutionary significant unit (ESU) can be defined as a population or group of populations that merits priority for conservation and separate management because of high genetic and ecological distinctiveness from other such units. Management units (MUs) are defined as populations that are demographically independent of one another; that is, their population dynamics depend mostly on local birth and death rates, and not on genetically effective migration. Identification of MUs – similar to “stocks” widely referred to in fisheries management – is useful for short-term management, such as managing habitat, delineating fishing areas, setting harvest rates, and monitoring population status. Against this background, the goal of our review and synthesis was to summarize knowledge and recommend critical work yet to be done regarding conservation of tilapias, approaching this task in a species-by-species manner. With the exceptions of Oreochromis niloticus, O. mossambicus, and Sarotherodon melanotheron, the body of existing work regarding genetic and adaptive differentiation of populations of tilapias is insufficient to inform identification of evolutionary significant units, a knowledge gap that should be addressed by targeted research. We note that competition and interspecific hybridization caused by introductions of tilapias for aquaculture purposes jeopardizes the genetic resources of certain native tilapia species. We hope that our review and synthesis spark critical discussion of tilapia conservation within the tilapia aquaculture, management, and conservation communities.

Significant population genetic structuring but a lack of phylogeographic structuring in the endemic Tasmanian tree frog (Litoria burrowsae)

Conservation of frogs is of global concern, owing to declines resulting from habitat destruction, global climate change, and disease. Knowledge of genetic variation in frog species is therefore desirable for the identification of management units. Here we surveyed mitochondrial DNA sequence variation in the Tasmanian endemic hylid frog Litoria burrowsae, which is infected by chytrid fungus, Batrachochytrium dendrobatidis, and may be declining. Neither phylogeographic structure nor deep phylogenetic divergence was detected in the species, although its populations were highly differentiated with respect to haplotype frequencies. The low-haplotype diversity in L. burrowsae suggests a recent bottleneck in the species, and population genetic structuring may reflect isolation by distance as well as founder effects associated with range expansion. Three putative management units were identified that require verification based on nuclear DNA variation and adaptation to local environments.

Spatio-temporal genetic structuring of brown trout (Salmo trutta L.) populations within the River Luga, northwest Russia

The brown trout populations of the Baltic Sea region have been drastically affected by various human activities during the past century. Due to their propensity to home to their natal site to spawn and their tendency to evolve local adaptations, populations may be genetically differentiated in water systems where no physical barriers preventing interbreeding exist. Consequently, identification of management units, a prerequisite for appropriate conservation and management planning, cannot necessarily be deduced from the physical properties of the habitat. In this study, microsatellite markers were employed to assess the spatio-temporal genetic structuring of inter-connected brown trout populations from a river-system in Northwest Russia. Populations were found to be genetically differentiated from each other (global F ST 0.06) and the genetic structuring within the river to follow an isolation by distance pattern. Indications of temporal stability were found in some populations, however others appeared to be temporally unstable suggesting differences in the demographic forces affecting the populations. Based on the observed isolation by distance pattern of genetic differentiation, preserving several breeding sites spaced evenly throughout the river-system would appear to be more appropriate than focussing conservation effort on any single stretch of the river.

Identification of management units using population genetic data

The identification of management units (MUs) is central to the management of natural populations and is crucial for monitoring the effects of human activity upon species abundance. Here, we propose that the identification of MUs from population genetic data should be based upon the amount of genetic divergence at which populations become demographically independent instead of the current criterion that focuses on rejecting panmixia. MU status should only be assigned when the observed estimate of genetic divergence is significantly greater than a predefined threshold value. We emphasize the need for a demographic interpretation of estimates of genetic divergence given that it is often the dispersal rate of individuals that is the parameter of immediate interest to conservationists rather than the historical amount of gene flow.

Research on deer taxonomy and its relevance to management

Taxonomic classifications are based on phylogenetic relationships, which can be inferred from paleontological, morphological, or genetic data. In this paper, I describe recent molecular genetic data that contribute to the understanding of taxonomic and phylogenetic relationships of the Cervidae at the family, species, subspecies, and population levels. At higher taxonomic levels, the relationships of cervids have been inferred from several molecular genetic markers. Mitochondrial DNA and nuclear DNA sequences (e.g., casein genes) have been used to infer the relationships of Cervidae to other artiodactyl families and the relationships among cervid subfamilies, genera, and species. The data used in such analyses can be extended to practical management applications such as forensic species identification. DNA sequences and allele frequencies of proteins and microsatellite loci can also be used to infer relationships among congeneric species, subspecies, and populations. Understanding relationships at these lower taxonomic levels is useful in several management contexts. Species relationships are important in cases where interspecific competition or hybridization may be important, as with white-tailed deer (Odocoileus virginianus) and mule deer (O. hemionus) in western North America. Quantification of the genetic differentiation among subspecies and populations is useful for identification of management units and inference of the extent of common ancestry and gene flow. Caribou (Rangifer tarandus granti) and domestic reindeer (R. t. tarandus) are discussed as an example of subspecies that remain genetically differentiated 110 y after the introduction of domestic reindeer to wild caribou ranges in Alaska. Genetic data also show that four wild caribou herds in Arctic Alaska comprise one interbreeding population, although each herd has a different calving range. The concepts of subspecies, populations, and other intra-specific taxa are discussed.

The vegetation types and management units of Goedverwacht farm in the mixed bushveld of the Northern Province, South Africa

An analysis of the vegetation of Goedverwacht farm in the mixed bushveld of the Northern Province is presented. Releves were compiled in 33 stratified random sample plots. Eight distinct plant communities were identified by means ofBraun-Blanquet pro-cedures. Detrended correspondence analysis (DCA) was applied to the floristic data set using the computer programme DECORANA (Detrended Correspondence Analysis) to determine a probable environmental gradient and to facilitate in the identification of management units. The computer programme CANOCO (Canonical Correspondence Analysis) was used to apply canonical correspondence analysis (CCA) to the floristic data set. Two management units were determined by means of vegetation ordinations and soil data. A classification, description and ecological interpretation of the plant communities as well as a description of the management units are presented.

The vegetation and identification of management units of the Honnet Nature Reserve, Northern Province, South Africa

An analysis of the vegetation of the Honnet Nature Reserve, Northern Province is presented. Releves were compiled in 56 stratified random sample plots. The Braun- Blanquet procedure revealed 12 distinct plant communities and four sub-communities. The Variable Quadrant Plot Method was used in the structural analysis of the communities and management units. The data were ordinated using Detrended Correspondence Analysis (DECORANA) to determine possible relations and gradients between and in the plant communities. Six management units were identified by means of the vegetation ordination, plant communities and the physical environment. A hierarchical classification, description and ecological interpretation of the vegetation units and a descrip- tion of the management units are presented.

The vegetation and identification of management units of the Imberbe Game Lodge in the mixed bushveld of the north-western Transvaal

An analysis of the vegetation of the Imberbe Game Lodge in the mixed bushveld of the north-western Transvaal is presented. Releves were compiled in 39 stratified random sample plots. Four distinct plant communities were identified by means of Braun-Blanquet procedures. The data were ordinated using detrended correspondence analysis (DECORANA) to investigate possible relationships and gradients in and between the plant communities. Three management units were determined by means of a vegetation ordination. A hierarchical classification, description and ecological interpretation of the plant communities as well as a description of the management units are presented.