scholarly journals Urbanization and Population Genetic Structure of the Panama City crayfish (Procambarus econfinae)

2019 ◽  
Vol 111 (2) ◽  
pp. 204-215
Author(s):  
Sarah I Duncan ◽  
Ellen P Robertson ◽  
Robert J Fletcher ◽  
James D Austin
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Habitat Loss ◽  
Legal Protection ◽  
Habitat Modification ◽  
Panama City ◽  
Habitat Patches ◽  
Anthropogenic Habitat ◽  
Habitat Loss And Fragmentation

Abstract For species with geographically restricted distributions, the impacts of habitat loss and fragmentation on long-term persistence may be particularly pronounced. We examined the genetic structure of Panama City crayfish (PCC), Procambarus econfinae, whose historical distribution is limited to an area approximately 145 km2, largely within the limits of Panama City and eastern Bay County, FL. Currently, PCC occupy approximately 28% of its historical range, with suitable habitat composed of fragmented patches in the highly urbanized western portion of the range and managed plantations in the more contiguous eastern portion of the range. We used 1640 anonymous single-nucleotide polymorphisms to evaluate the effects of anthropogenic habitat modification on the genetic diversity and population structure of 161 PCC sampled from across its known distribution. First, we examined urban habitat patches in the west compared with less-developed habitat patches in the east. Second, we used approximate Bayesian computation to model inferences on the demographic history of eastern and western populations. We found anthropogenic habitat modifications explain the genetic structure of PCC range-wide. Clustering analyses revealed significant genetic structure between and within eastern and western regions. Estimates of divergence between east and west were consistent with urban growth in the mid-20th century. PCC have low genetic diversity and high levels of inbreeding and relatedness, indicating populations are small and isolated. Our results suggest that PCC have been strongly affected by habitat loss and fragmentation and management strategies, including legal protection, translocations, or reintroductions, may be necessary to ensure long-term persistence.

Diet of two fossorial herbivores in a seasonally snow-covered environment

2017 ◽  
Vol 39 (2) ◽  
pp. 169 ◽  
Author(s):  
K. Green ◽  
N. E. Davis ◽  
W. A. Robinson
Keyword(s):  
Range Expansion ◽  
Oryctolagus Cuniculus ◽  
Habitat Modification ◽  
Alpine Treeline ◽  
Winter Snow ◽  
Anthropogenic Habitat ◽  
Eastern Australia ◽  
European Rabbits ◽  
Elevational Range

To understand the recent elevational range expansion of European rabbits (Oryctolagus cuniculus) with declining snow cover and earlier snow thaw we examined their diet in relation to that of long-term residents, common wombats (Vombatus ursinus). The colonisation of eastern Australia by rabbits was effectively completed by 1910 when they reached an elevation of 1500 m (the winter snowline). Rabbits began to penetrate higher elevations only from the 1970s in association with anthropogenic habitat modification. Since 2011, rabbits have occupied elevations to the alpine treeline (~1850 m) throughout the year without the ameliorating presence of infrastructure or anthropogenically modified vegetation. Rabbits and wombats are both grazers preferring grasses (largely inaccessible beneath winter snow) and are spatially restricted in their foraging by their need to return to their burrows. Wombats used a much wider foraging range, enabling them to select preferred food. Rabbits, with a much smaller range, were constrained in their choice of forage mainly to plants that projected above the snow. Unexpectedly, rabbits fed intensively on leaves of eucalypts, food not typically consumed in substantial quantities by this species. These leaves, on stems regenerating after fire, will diminish in availability as stems mature, possibly halting the range expansion of rabbits.

scholarly journals High levels of genetic diversity and an absence of genetic structure among breeding populations of the endangered Rufous-backed Bunting in Inner Mongolia, China: implications for conservation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Shi Li ◽  
Dan Li ◽  
Lishi Zhang ◽  
Weiping Shang ◽  
Bo Qin ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Mitochondrial Dna ◽  
Genetic Structure ◽  
Endangered Species ◽  
Habitat Loss ◽  
Inner Mongolia ◽  
Avian Species ◽  
Genetic Structuring ◽  
Breeding Populations ◽  
The Impact

Abstract Background The Rufous-backed Bunting, Emberiza jankowskii, is an endangered species that is primarily distributed in Inner Mongolia, China. The main threats to the continued persistence of this species are habitat loss and degradation. However, the impact of population loss on genetic diversity remains unclear. To support future conservation and management efforts, we assessed the genetic diversity and population structure of E. jankowskii using mitochondrial DNA and microsatellites. Methods Blood samples were collected from 7‒8-day-old nestlings in Inner Mongolia, China between May and August of 2012 and 2013. Mitochondrial DNA sequences and microsatellite markers were used to assess the genetic diversity, genetic structure and inbreeding of E. jankowskii. The results of genetic diversity and inbreeding were compared to other avian species. Results We found an unexpectedly high level of genetic diversity in terms of mitochondrial DNA and microsatellite compared to other avian species. However, there were high levels of gene flow and minimal genetic structuring, among the fragmented breeding populations of E. jankowskii in Inner Mongolia. These findings suggest that E. jankowskii in Inner Mongolia is a metapopulation. Despite the high genetic diversity of E. jankowskii, local populations in each small patch remain at risk of extinction due to habitat loss. In addition, the E. jankowskii population has a high risk of inbreeding. Conclusions To minimize further loss of genetic diversity of this endangered species, we suggest that the E. jankowskii in Inner Mongolia should be considered as a protected species for management purposes. Conservation efforts should concentrate on E. jankowskii habitat management. This may be most effectively achieved by protecting the current breeding habitats and prohibiting over-grazing.

scholarly journals Using the Lonsdorf model for estimating habitat loss and fragmentation effects on pollination service

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Ehsan Rahimi ◽  
Shahindokht Barghjelveh ◽  
Pinliang Dong
Keyword(s):  
Habitat Loss ◽  
Critical Factor ◽  
Agricultural Landscapes ◽  
Forest Patches ◽  
Habitat Amount ◽  
Habitat Patches ◽  
Farm Level ◽  
Habitat Loss And Fragmentation ◽  
Lonsdorf Model ◽  
Landscape Level

AbstractOne of the most important issues related to landscape ecology and ecosystem services is finding the pattern of habitat patches that offers the highest pollination in agricultural landscapes. In this regard, two processes of habitat loss and fragmentation strongly affect the relationship between pollination and the pattern of habitat patches. In the present study, we aimed to examine the effects of habitat loss and fragmentation on pollination separately. For this purpose, first, we generated different simulated agricultural landscapes, including two habitats of forest and agriculture. Then, according to the Lonsdorf model, we estimated the potential of the simulated landscapes in providing pollination in different scenarios. Finally, using statistical models, we estimated the effects of habitat loss and fragmentation on pollination at the landscape and farm levels. Our results showed that the effects of habitat loss and fragmentation on pollination were completely different at the landscape and farm levels. At the landscape level, fragmentation negatively affected pollination, but at the farm level, the maximum pollination rate was observed in the landscapes with a high degree of fragmentation. Regarding the habitat loss effects, our results showed that pollination decreased linearly at the landscape level as habitat amount decreased, but at the farm level, it decreased exponentially. The present study considered the level of analysis (i.e., landscape and farm levels) as a critical factor affecting pollination changes caused by fragmentation. We showed that using the Lonsdorf model could lead to confusing results for the landscape ecologists and alert farmers who want to reduce the adverse effects of fragmentation on their products by creating new forest patches. Therefore, agriculturalists and landscape ecologists should consider that the pollination rate at the landscape and farm levels is completely different according to the model and provide contradictory results about the process of habitat loss effects on pollination.

scholarly journals Fitness Implications of the Mating System and  Reproductive Ecology of Tuatara

2021 ◽  
Author(s):  
◽  
Jennifer Ann Moore
Keyword(s):  
Genetic Diversity ◽  
Sexual Selection ◽  
Mating System ◽  
Population Genetic ◽  
Reproductive Ecology ◽  
Barrier Island ◽  
Habitat Modification ◽  
Population Genetic Diversity ◽  
Individual Fitness

<p>Sexual selection and reproductive strategies affect individual fitness and population genetic diversity. Long-standing paradigms in sexual selection and mating system theory have been overturned with the recent integration of behavioural and genetic techniques. Much of this theory is based on avian systems, where a distinction has now been made between social and genetic partners. Reptiles provide contrast to well-understood avian systems because they are ectothermic, and phylogenetic comparisons are not hindered by complicated patterns of parental care. I investigate the implications of the mating system and reproductive ecology on individual fitness and population genetic diversity of tuatara, the sole extant representative of the archaic reptilian order Sphenodontia. Long-term data on individual size of Stephens Island tuatara revealed a density-dependent decline in body condition driven by an apparently high population growth rate resulting from past habitat modification. Spatial, behavioural, and genetic data from Stephens Island tuatara were analysed to assess territory structure, the mating system, and variation in male fitness. Large male body size was the primary predictor of 1) physical access to females, 2) competitive ability, and 3) mating and paternity success. Seasonal monogamy predominates, with probable long-term polygyny and polyandry. Annually, male reproduction is highly skewed in the wild and in captivity. Over 80% of offspring from a captive population on Little Barrier Island were sired by one male and multiple paternity was found in approximately 18% of these clutches, although it was not detected in any wild clutch. The dominance structure has lead to reduced genetic variation in the recovering Little Barrier Island population. Stephens Island tuatara show fine-scale population genetic structuring that appears to be driven by past habitat modification and a sedentary lifestyle in the absence of sex-biased dispersal or migration. These results will improve conservation management of tuatara by providing guidelines for maximising genetic diversity of small and captive populations and will aid in selecting founders for translocated populations. Because of the archaic phylogenetic position of tuatara, this study provides a baseline for comparisons of mating system evolution in reptiles.</p>

scholarly journals Fitness Implications of the Mating System and  Reproductive Ecology of Tuatara

2021 ◽  
Author(s):  
◽  
Jennifer Ann Moore
Keyword(s):  
Genetic Diversity ◽  
Sexual Selection ◽  
Mating System ◽  
Population Genetic ◽  
Reproductive Ecology ◽  
Barrier Island ◽  
Habitat Modification ◽  
Population Genetic Diversity ◽  
Individual Fitness

<p>Sexual selection and reproductive strategies affect individual fitness and population genetic diversity. Long-standing paradigms in sexual selection and mating system theory have been overturned with the recent integration of behavioural and genetic techniques. Much of this theory is based on avian systems, where a distinction has now been made between social and genetic partners. Reptiles provide contrast to well-understood avian systems because they are ectothermic, and phylogenetic comparisons are not hindered by complicated patterns of parental care. I investigate the implications of the mating system and reproductive ecology on individual fitness and population genetic diversity of tuatara, the sole extant representative of the archaic reptilian order Sphenodontia. Long-term data on individual size of Stephens Island tuatara revealed a density-dependent decline in body condition driven by an apparently high population growth rate resulting from past habitat modification. Spatial, behavioural, and genetic data from Stephens Island tuatara were analysed to assess territory structure, the mating system, and variation in male fitness. Large male body size was the primary predictor of 1) physical access to females, 2) competitive ability, and 3) mating and paternity success. Seasonal monogamy predominates, with probable long-term polygyny and polyandry. Annually, male reproduction is highly skewed in the wild and in captivity. Over 80% of offspring from a captive population on Little Barrier Island were sired by one male and multiple paternity was found in approximately 18% of these clutches, although it was not detected in any wild clutch. The dominance structure has lead to reduced genetic variation in the recovering Little Barrier Island population. Stephens Island tuatara show fine-scale population genetic structuring that appears to be driven by past habitat modification and a sedentary lifestyle in the absence of sex-biased dispersal or migration. These results will improve conservation management of tuatara by providing guidelines for maximising genetic diversity of small and captive populations and will aid in selecting founders for translocated populations. Because of the archaic phylogenetic position of tuatara, this study provides a baseline for comparisons of mating system evolution in reptiles.</p>

Spatial genetic structure of a keystone long-lived semiarid shrub: historical effects prevail but do not cancel the impact of recent severe habitat loss on genetic diversity

2020 ◽  
Vol 21 (5) ◽  
pp. 853-867 ◽  
Author(s):  
Ana González-Robles ◽  
Antonio J. Manzaneda ◽  
Teresa Salido ◽  
Francisco Valera ◽  
Cristina García ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Habitat Loss ◽  
Spatial Genetic Structure ◽  
The Impact

A meta-analysis of the effects of habitat loss and fragmentation on genetic diversity in mammals

2019 ◽  
Vol 94 ◽  
pp. 69-76 ◽  
Author(s):  
Ana Lino ◽  
Carlos Fonseca ◽  
Danny Rojas ◽  
Erich Fischer ◽  
Maria João Ramos Pereira
Keyword(s):  
Genetic Diversity ◽  
Habitat Loss ◽  
Meta Analysis ◽  
Habitat Loss And Fragmentation

scholarly journals Genetic diversity of Dactylorhiza incarnata (Orchidaceae) in northern Poland

2016 ◽  
Vol 85 (2) ◽  
Author(s):  
Aleksandra M. Naczk ◽  
Igor J. Chybicki ◽  
Marek S. Ziętara
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Genetic Structure ◽  
Genetic Differentiation ◽  
Pollen Dispersal ◽  
Species Level ◽  
Bottleneck Effect ◽  
Northern Poland ◽  
Habitat Loss And Fragmentation ◽  
Population Numbers

The genetic structure of <em>Dactylorhiza incarnata</em> var. <em>incarnata</em> populations is shaped not only by historical events such as recolonization after ice sheet retreat or limited seed and pollen dispersal, but also the bottleneck effect. During the last decade, <em>D. incarnata</em> var. <em>incarnata</em> has also experienced a strong decline in population numbers and sizes, due to habitat loss and fragmentation. In the present research genetic diversity was examined in eight populations located in northern Poland, using six nuclear microsatellites loci. At the species level our results showed a moderate mean level of genetic diversity (<em>A</em> = 4.67; <em>A</em><span><sub>e</sub></span> = 2.73; <em>R</em><span><sub>s</sub></span> = 4.48; <em>H</em><span><sub>o</sub></span> = 0.438; <em>F</em><span><sub>IS</sub></span> = 0.224), which varied among the studied populations (<em>A</em>: 2.17–3.67; <em>A</em><span><sub>e</sub></span>: 1.55–2.69; <em>R</em><span><sub>s</sub></span>: 1.31–1.61; <em>H</em><span><sub>o</sub></span>: 0.292–0.631; <em>F</em><span><sub>IS</sub></span>: −0.283–0.340). A considerable overabundance of homozygotes was detected in four populations (<em>F</em><span><sub>IS</sub></span> within the range of 0.067–0.340), and in the remaining populations an excess of heterozygotes was observed. The average apparent out-crossing rate was also calculated (<em>t</em><span><sub>a</sub></span> = 0.980), and primarily indicated a tendency to out-cross within the species. Moderate genetic differentiation was found among the studied populations (<em>F</em><span><sub>ST</sub></span> = 0.149; <em>R</em><span><sub>ST</sub></span> = 0.174; <em>p</em> &lt; 0.05). The differentiation of the populations corresponded to relatively low gene flow value (<em>N</em><span><sub>m</sub></span> = 0.426) among populations, which amounted to only one migrant every second generation.

scholarly journals The effects of long-term translocation on population genetic structure of Ayu in Japan: Management implications for a recreationally fished iconic species

2021 ◽  
Author(s):  
Shuichi Kitada
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Genetic Structure ◽  
Population Genetic Structure ◽  
Population Genetic ◽  
Recreational Fishing ◽  
Plecoglossus Altivelis ◽  
In The Wild ◽  
One Year

Ayu (Plecoglossus altivelis altivelis), an important freshwater fisheries resource and popular recreational fishing species, lives for only one year and has a single breeding season. To supplement increased recreational fishing demand, huge numbers of wild–born landlocked juvenile Ayu have been translocated from Lake Biwa into most Japanese rivers for more than 50 generations. Hatchery-born amphidromous fish (including amphidromous and landlocked form hybrids) have also been released for many generations. Hatchery–born fish have low survival and maladapted behaviour in the wild. Landlocked and amphidromous forms of Ayu easily hybridise, but survival of progeny of landlocked forms is very low in seawater. Repeat backcrossing may cause introgression of landlocked forms into amphidromous populations, but this has not been previously identified. Study objectives using genetic data from Ayu from 118 locations throughout the distribution of this species in Japan are to describe contemporary population structure, genetic diversity, and admixture proportions of Ayu forms in populations, and to evaluate how human-induced translocation has affected population genetic structure. The analyses of published genotypes of 12 microsatellite markers provide strong evidence for very high gene flow between populations, but population structure has been retained in several regions, and several populations are nested. Genetic diversity is surprisingly homogeneous. Hybridisation between landlocked and amphidromous forms has occurred in all populations, with a mean hybrid proportion (± standard deviation) of 37 ± 10%, ranging 15%–60%. Results are discussed in relation to the conservation and management of this species. Recommendations are made to reduce translocation and hatchery releases, by establishing rivers and/or areas in every prefecture where translocation does not occur. Release of juveniles is of value for short–term management objectives, but management of spawning escapements, and improving the spawning and nursery habitat are important for this species long–term sustainability.

scholarly journals Reduced Global Genetic Differentiation of Exploited Marine Fish Species

2020 ◽  
Author(s):  
Miguel Gandra ◽  
Jorge Assis ◽  
Manuel Ramos Martins ◽  
David Abecasis
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Genetic Differentiation ◽  
Marine Fish ◽  
Fish Species ◽  
Population Differentiation ◽  
Environmental Changes ◽  
Meta Analysis ◽  
Genetic Connectivity

Abstract Knowledge on genetic structure is key to understand species connectivity patterns and to define the spatiotemporal scales over which conservation management plans should be designed and implemented. The distribution of genetic diversity (within and among populations) greatly influences species ability to cope and adapt to environmental changes, ultimately determining their long-term resilience to ecological disturbances. Yet, the drivers shaping connectivity and structure in marine fish populations remain elusive, as are the effects of fishing activities on genetic subdivision. To investigate these questions, we conducted a meta-analysis and compiled genetic differentiation data (FST/ΦST estimates) for more than 170 fish species from over 200 published studies globally distributed. We modeled the effects of multiple life-history traits, distance metrics, and methodological factors on observed population differentiation indices and specifically tested whether any signal arising from different exposure to fishing exploitation could be detected. Although the myriad of variables shaping genetic structure makes it challenging to isolate the influence of single drivers, results showed a significant correlation between commercial importance and genetic structure, with widespread lower population differentiation in commercially exploited species. Moreover, models indicate that variables commonly used as proxy for connectivity, such as larval pelagic duration, might be insufficient, and suggest that deep-sea species may disperse further. Overall, these results contribute to the growing body of knowledge on marine genetic connectivity and suggest a potential effect of commercial fisheries on the homogenization of genetic diversity, highlighting the need for additional research focused on dispersal ecology to ensure long-term sustainability of exploited marine species.

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