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ABSTRACTInvasive alien plant species (IAPs) represent one of the main biological threats to biodiversity worldwide. Information about their phenotypic plasticity are needed to increase awareness about their future invasive potential. A study about phenotypic plasticity in response to contrasting light regimes and its quantification by a plasticity index (PI) of two IAPs (Ailanthus altissima and Robinia pseudoacacia) inside a Strict Nature Reserve was conducted. R. pseudoacacia showed a 70% higher PI, with a strongly greater value at morphological leaf level, associated with a greater ability to survive and grow in forest understory, explaining its greater widespread. Otherwise, A. altissima showed its highest PI at physiological level, which was associated with the ability to colonize and grow in environments with high-light regimes. Based on these results, the conservative management has limited the presence of A. altissima by its lower ability to grow in forest understory. In fact, the small-scale gaps in the forest infrastructure, that could allow its recruitment, are originated only from the death of a single tree or small group of trees. Regarding R. pseudoacacia, it is critical to maintain this type of management because any disturbances resulting in large openings could further promote its presence inside the Reserve. 相似文献
73.
Krystina D. Mossop Nicholas P. Moran David G. Chapple Bob B. M. Wong 《Landscape Ecology》2017,32(5):1065-1078
Context
Dispersal has important fitness consequences for individuals, populations, and species. Despite growing theoretical insights into the evolution of dispersal, its behavioral underpinnings remain empirically understudied, limiting our understanding of the extent and impact of responses to landscape-level heterogeneity of environments, and increasing the risk of inferring species-level responses from biased population sampling.Objectives
We asked if predictable ecological variation among naturally fragmented arid waterbodies is correlated with disparate dispersal responses of populations of the desert goby Chlamydogobius eremius, which naturally inhabits two habitat “types” (permanent springs, ephemeral rivers), and different levels of hydrological connectivity (high and low) that potentially convey different costs and benefits of dispersal.Methods
To test for possible behavioral divergence between such populations, we experimentally compared the movement behaviors (correlates of emigration and exploration) of wild-caught fish. We used two biologically relevant spatial scales to test movement relevant to different stages of the dispersal process.Results
Behavior differed at both spatial scales, suggesting that alternative dispersal strategies enable desert gobies to exploit diverse habitat patches. However, while emigration was best predicted by the connectivity (flood risk) of fish habitats, exploration was linked to their habitat type (spring versus river).Conclusions
Our findings demonstrate that despite a complex picture of ecological variation, key landscape factors have an overarching effect on among-population variation in dispersal traits. Implications include the maintenance of within-species variation, potentially divergent evolutionary trajectories of naturally or anthropogenically isolated populations, and the direction of future experimental studies on the ecology and evolution of dispersal behavior.74.
Pedro Martínez-Gómez Angela S. Prudencio Thomas M. Gradziel Federico Dicenta 《Euphytica》2017,213(8):197
Regulation of flowering time in almond, as in other Prunus species, is a complex process involving both chill and heat requirements. Following exposure to appropriate consecutive periods of cold and warm temperatures, the buds break dormancy and sprout or flower depending on bud type. To maximize flowering and subsequent vegetative growth and fruit set, chilling and ensuing warm temperature requirements have to be fully satisfied. Because of its potential for very early flowering, flowering time in almond is a major determinant of its adaptation to new environments. In colder regions, Late-flowering is often necessary to avoid frost damage during and just after flowering. Consequently, the selection of delayed flowering times remains an important objective in almond improvement programs. Flowering time is considered a quantitative though highly heritable trait. In addition, a dominant gene (Late flowering, Lb), originally identified in a spontaneous mutation of the Californian almond cultivar ‘Nonpareil’, was also described. The objective of this review is a comparative analysis of the effects of regional adaptation, breeding and mutation on the delay of flowering time in new almond cultivars. Findings indicate that the adaptation of almonds from the Mediterranean basin to colder regions in Northern Europe and America has been mainly achieved through delayed flowering. These adapted late-flowering cultivars have usually been developed by selecting desired quantitative genes within each regional germplasm. Additional progress thus appears achievable with a more comprehensive understanding of the quantitative and qualitative genetics controlling this trait. The use of molecular markers for the early selection of genes conferring late flowering, including both spontaneous mutations as well as unique regional germplasm, should allow development of even later cultivars including ultra-late cultivars flowering as into April. 相似文献
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76.
Agus Purwito G. A. Wattimena Muhamad Syukur Sobir Ferdhi I. Nuryana Heri Harti Awang Maharijaya 《Euphytica》2017,213(10):237
Potato is one of the most important crops in the world, including in the tropics. Potato requires low temperatures or cool climate for optimum tuber yield, which in the tropics, can be obtained mostly in high altitude growing areas. The limitation of land availability for potato production in highland areas of some tropical countries has steered the recent development of potato production to medium altitude areas. The objective of our study is to identify potato accessions with promising levels of heat resistance in laboratory and with good adaptation to medium altitude in the field. We used in vitro assay to screen a number of potato clones with possible resistance to heat stress on the basis literature and database of the International Potato Center, supplemented with the collection of Bogor Agricultural University. We then continued with verification of selected clones using field test in high altitude (1300 m above sea level) and medium altitude (700 m above sea level) areas. Our result showed that there is considerable variation of S. tuberosum for their adaptation to medium altitude areas in the tropics that can be exploited in breeding programs. We identified one genotype PKHT 2013-06 that was superior for its ability to produce tubers under extreme conditions. Thus, it might be very suitable to be used in a breeding program to develop tolerant varieties of potato to medium altitude areas in the tropics. 相似文献
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Context
Landscape graphs are widely used to model connectivity and to support decision-making in conservation planning. Compartmentalization methods applied to such graphs aim to define clusters of highly interconnected patches. Recent studies show that compartmentalization based on modularity is suitable, but it applies to non-weighted graphs whereas most landscape graphs involve weighted nodes and links.Objectives
We propose to adapt modularity computation to weighted landscape graphs and to validate the relevance of the resulting compartments using demographic or genetic data about the patches.Methods
A weighted adjacency matrix was designed to express potential fluxes, associating patch capacities and inter-patch distances. Eight weighting scenarios were compared. The statistical evaluation of each compartmentalization was based on Wilks’ Lambda. These methods were performed on a grassland network where patches are documented by annual densities of water voles in the Jura massif (France).Results
The scenarios in which patch capacity is assigned a small weight led to the more relevant results, giving high modularity values and low Wilks’ Lambda values. When considering a fixed number of compartments, we found a significant negative correlation between these two criteria. Comparison showed that compartments are ecologically more valid than graph components.Conclusions
The method proposed is suitable for designing ecologically functional areas from weighted landscape graphs. Maximum modularity values can serve as a guide for setting the parameters of the adjacency matrix.80.