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opencc-zeroAug 2020View details →

Breaking ecological barriers: anthropogenic disturbance leads to habitat transitions, hybridization, and high genetic diversity

Genetic diversity is expected to erode in disturbed habitats through strong selection, local extinctions, and recolonization associated with genetic bottlenecks and restricted gene flow. Despite this general prediction and over three decades of population genetics studies, our understanding of the long-term effect of environmental disturbance on local and regional genetic diversity remains limited. We conducted a population genetic survey of the microcrustacean Daphnia across a landscape subject to anthropogenic stressors from a century of industrial mining. At the local scale we found moderate genetic diversity (i.e., low clonal diversity), characteristic of habitat-specific selective sweeps and local extinctions, but high diversity and strong genetic structure at the regional scale despite the shared watershed of many lakes and exceptional dispersal ability of daphniids. Many habitats experienced changes in species assemblages, with the obligate asexual Daphnia pulex lineages—known only to inhabit ponds—dominating disrupted urban lakes. This habitat transition (pond to lake) was likely facilitated by the disruption of ecological barriers maintaining the genomic separation of these young species. Thus, disrupted habitats can exhibit complex and unexpected genetic patterns of local extinctions and recolonizations, followed by habitat transitions, hybridization and potential speciation events that are difficult to predict and should not be underestimated.

opencc-zeroMar 2020View details →

Habitat transitions alter the adaptive landscape and shape phenotypic evolution in needlefishes (Belonidae)

Habitat occupancy can have a profound influence on macroevolutionary dynamics, and a switch in major habitat type may alter the evolutionary trajectory of a lineage. In this study we investigate how evolutionary transitions between marine and freshwater habitats affect macroevolutionary adaptive landscapes, using needlefishes (Belonidae) as a model system. We examined the evolution of body shape and size in marine and freshwater needlefishes and tested for phenotypic change in response to transitions between habitats. Using micro-computed tomographic (µCT) scanning and geometric morphometrics, we quantified body shape, size, and vertebral counts of 31 belonid species. We then examined the pattern and tempo of body shape and size evolution using phylogenetic comparative methods. Our results show that transitions from marine to freshwater habitats have altered the adaptive landscape for needlefishes and expanded morphospace relative to marine taxa. We provide further evidence that freshwater taxa attain reduced sizes either through dwarfism (as inferred from axial skeletal reduction) or developmental truncation (as inferred from axial skeletal loss). We propose that transitions to freshwater habitats produce morphological novelty in response to novel prey resources and changes in locomotor demands. We find that repeated invasions of different habitats have prompted predictable changes in morphology.

opencc-zeroMay 2022View details →

Data from: Habitat change and its consequences on reef fish specialization in biogeographic transition zones

Aim Reef fishes are commonly recognized as sentinels of the ongoing tropicalization in biogeographic transition zones between temperate and tropical areas. Despite the reliance of these marine ectotherms on the benthos, the importance of benthic habitat has rarely been considered as a factor constraining fish distribution. Therefore, our study aims at examining the consequences of both temperature and benthic variations on the fish fauna and diagnosing potential sentinels of these environmental changes. Location Taiwan, West Pacific. Taxon Teleostei (184 species). Methods We examined how the partitioning of habitats can influence the specialization of fish fauna along a latitudinal gradient. We diagnosed 'specialist' and 'generalist' fishes in this partitioning. For each specialist, we further evaluated whether its distribution is constrained by temperature, benthic habitat, or both factors combined. The change in sea surface temperature over the last three decades was also monitored. Results Fish fauna showed the highest specialization when tropical and subtropical partitions of habitat were considered. Fifty-one tropical specialists, seven subtropical specialists, and 21 possible generalists were identified. Among specialists, 13 species were associated with temperature, 19 with habitat, and 26 with both factors. Steady warming occurred across latitudes but was accentuated in the winter of subtropical habitat. Main conclusions Our results suggested that the distribution of some specialist fishes was constrained only by temperature while the distribution of some others also depended on the availability of benthic habitats. Consequently, under global warming, the distribution of some specialists might shift in a manner that follows the movement of isotherms, while the distribution of others might also be conditioned by the poleward shifts of benthos. A temporal mismatch between the emergence of suitable thermal environments and the arrival of some specialists may exist. Therefore, the tropicalization of high-latitude areas may be characterized by different waves of colonization.

opencc-zeroJul 2024View details →

Data from: Habitat security pattern of migratory birds in Dalian (transit station)

Dalian is an important "transit station" for migratory birds in the East Asian-Australasian flyway,located at the throat of the habitat of migratory birds in the Yellow (Bohai) Sea, and is an important stop,foraging and breeding place for migratory birds in the long-distance migration process.Based on the idea of Land-sea integration, this study aims to promote the improvement of the ecological environment of migratory bird habitats, enhance species diversity, and strengthen population exchange, identify the habitat security pattern in the "transit station" area, and put forward restoration suggestions. By selecting important habitat patches from the MSPA model, landscape connectivity analysis, and important bird habitats in Dalian, the random movement of birds was simulated through circuit theory, and the ecological corridors and important corridor nodes of migratory birds were identified to construct a habitat security pattern. The results of the study identified the ecological reserves, key areas, and areas to be restored in the study area. Among them, the areas to be restored are graded according to the importance of ecological security, and targeted restoration strategies are proposed. The habitat security pattern of migratory birds constructed in this paper can provide a scientific basis for the protection of migratory bird habitats.

publicAug 2020View details →

Breaking ecological barriers: anthropogenic disturbance leads to habitat transitions, hybridization, and high genetic diversity

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publicMar 2020View details →

Habitat transitions alter the adaptive landscape and shape phenotypic evolution in needlefishes (Belonidae)

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publicJan 2024View details →

Data from: Divergent dynamics of sexual and habitat isolation at the transition between stick insect populations and species

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publicJun 2022View details →

Data from: Habitat change and its consequences on reef fish specialization in biogeographic transition zones

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opencc-zeroDec 2012View details →

Data from: Widespread and persistent invasions of terrestrial habitats coincident with larval feeding behavior transitions during snail-killing fly evolution (Diptera: Sciomyzidae)

Background: Transitions in habitats and feeding behaviors were fundamental to the diversification of life on Earth. There is ongoing debate regarding the typical directionality of transitions between aquatic and terrestrial habitats and the mechanisms responsible for the preponderance of terrestrial to aquatic transitions. Snail-killing flies (Diptera: Sciomyzidae) represent an excellent model system to study such transitions because their larvae display a range of feeding behaviors, being predators, parasitoids or saprophages of a variety of mollusks in freshwater, shoreline and dry terrestrial habitats. The remarkable genus Tetanocera (Tetanocerini) occupies five larval feeding groups and all of the habitat types mentioned above. This study has four principal objectives: (i) construct a robust estimate of phylogeny for Tetanocera and Tetanocerini, (ii) estimate the evolutionary transitions in larval feeding behaviors and habitats, (iii) test the monophyly of feeding groups and (iv) identify mechanisms underlying sciomyzid habitat and feeding behavior evolution. Results: Bayesian inference and maximum likelihood analyses of molecular data provided strong support that the Sciomyzini, Tetanocerini and Tetanocera are monophyletic. However, the monophyly of many behavioral groupings was rejected via phylogenetic constraint analyses. We determined that (i) the ancestral sciomyzid lineage was terrestrial, (ii) there was a single terrestrial to aquatic habitat transition early in the evolution of the Tetanocerini and (iii) there were at least 10 independent aquatic to terrestrial habitat transitions and at least 15 feeding behavior transitions during tetanocerine phylogenesis. The ancestor of Tetanocera was aquatic with five lineages making independent transitions to terrestrial habitats and seven making independent transitions in feeding behaviors. Conclusions: The preponderance of aquatic to terrestrial transitions in sciomyzids goes against the trend generally observed across eukaryotes. Damp shoreline habitats are likely transitional where larvae can change habitat but still have similar prey available. Transitioning from aquatic to terrestrial habitats is likely easier than the reverse for sciomyzids because morphological characters associated with air-breathing while under the water's surface are lost rather than gained, and sciomyzids originated and diversified during a general drying period in Earth's history. Our results imply that any animal lineage having aquatic and terrestrial members, respiring the same way in both habitats and having the same type of food available in both habitats could show a similar pattern of multiple independent habitat transitions coincident with changes in behavioral and morphological traits.

opencc-zeroDec 2015View details →

Data from: Seed to seedling transitions in successional habitats across a tropical landscape

Recognition that tree recruitment depends on the balance between seed arrival and seedling survival has led to a surge of interest in seed-dispersal limitation and seedling-establishment limitation in primary forests. Virtually unaddressed are comparisons of this balance in mature and early successional habitats. We assessed seed rain and seedling recruitment dynamics of tree species in primary forest, secondary forest and pasture released from grazing in a tropical agricultural landscape. Seed to seedling ratios (seed effectiveness; Φi) for 43 species in southern Mexico determined differences in the extent to which seeds produced seedlings by habitat, life history, and dispersal mode. Reproductive potential as estimated by the transition from seed rain to seedling recruitment, differed by habitats, and varied dramatically by life history and dispersal mode. Expected recruit densities (Eit) were higher for animal-dispersed than wind-dispersed species, and for non-pioneer than pioneer species. Non-pioneers and animal-dispersed species had higher expected relative recruit abundance (εit) in primary forest (median of 4 seeds recruit−1) whereas in secondary forest wind-dispersed pioneers had the highest expected relative recruit abundance (median of 16 seeds per recruit). In pastures, wind-dispersed pioneer species were most successful with many more seeds per recruit (median of 291) than both forest habitats. Seeds per recruit (Φi) appeared to decrease with increase in seed mass for 43 species for which data were available (r = –0.55, P < 0.001). This was associated with a negative correlation of Φi with seed size in primary forest (r = –0.50, P = 0.08 for 13 species); Φi was not correlated with seed size in secondary forest (n = 16) or pasture (n = 14). Metrics of seeds per recruit, expected recruit density and expected relative recruit abundance dramatically illustrate differences in barriers to recruitment in successional habitats.

FIG. 5 in Marine Habitat Transitions and Body-Shape Evolution in Lizardfishes and Their Allies (Aulopiformes)

FIG. 5. Results of principal component analysis depicting principal component 1 and principal component 2 with eight homologous landmarks and 70 semi-landmarks. Colored polygons represent distribution by marine habitat.

FIG. 6 in Marine Habitat Transitions and Body-Shape Evolution in Lizardfishes and Their Allies (Aulopiformes)

FIG. 6. Marine habitat transitions among Aulopiformes inferred on the time-calibrated phylogeny from Davis and Fielitz (2010). Outgroups trimmed from tree to highlight Aulopiformes. Benthic continental shelf to upper slope may range from approximately 0 to 500 meters depending on region, with most continental shelves breaking at 200 m. Deep-sea pelagic includes the zones below the epipelagic starting with the mesopelagic at 200 m. Maximum-likelihood character reconstruction of habitat shown with probabilities of states represented at nodes.

FIG. 3 in Marine Habitat Transitions and Body-Shape Evolution in Lizardfishes and Their Allies (Aulopiformes)

FIG. 3. Results of principal component analysis depicting principal component 1 and principal component 2 with eight homologous landmarks and 70 semi-landmarks. Colored polygons highlight distribution of specimens within families of lizardfishes.

FIG. 2 in Marine Habitat Transitions and Body-Shape Evolution in Lizardfishes and Their Allies (Aulopiformes)

FIG. 2. Example of fixed landmark (blue circles) and sliding semi-landmark (purple circles) locations on a lizardfish (SynoduS VariegatuS illustrated). Homologous fixed landmarks follow those from McMahan et al. (2011) and include: 1, anterior insertion of the dorsal fin on body; 2, posterior insertion of the dorsal fin on the body; 3, dorsal insertion of caudal fin; 4, ventral insertion of caudal fin; 5, posterior insertion of anal fin on the body; 6, anterior insertion of anal fin on body; 7, the point at which the interopercle meets the ventral body outline; 8, anterior tip of premaxilla. Digital image by R. P. Martin.

opencc-zeroMay 2023View details →

Critical transitions and evolutionary hysteresis in movement: Habitat fragmentation can cause abrupt shifts in dispersal that are difficult to revert

Under habitat fragmentation, plant species' survival hinges on the ability of individuals to disperse from one habitat patch to another. While there is evidence that severe habitat fragmentation leads to evolution of reduced dispersal ability and that such decreased mobility is generally detrimental for species' survival, it is unknown whether species adapt via a gradual loss in dispersal ability or via a sudden shift from frequent to infrequent dispersal between patches (i.e., a critical transition). Using both a spatially explicit deterministic and individual-based stochastic model of hydrochorous seed dispersal, we show that a small increase in inter-patch distance can generate an abrupt shift in plant seed dispersal strategy from long to short distances. Most importantly, we found that a substantial increase in connectivity between habitat fragments is required to reverse this loss of long-distance dispersal, due to an evolutionary hysteresis effect. Our theory prompts for re-consideration of the eco-evolutionary consequences of habitat fragmentation as restoring habitat connectivity may require restoration of much higher connectivity levels than currently assumed.

publicAug 2017View details →

Data from: Frequent and parallel habitat transitions as driver of unbounded radiations in the Cape flora

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publicSep 2016View details →

Data from: Seed to seedling transitions in successional habitats across a tropical landscape

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