The Iberian wall lizard Podarcis hispanica forms part of a species complex with several morphologically and geneti- cally distinct types and populations, which may or may not be reproductively isolated. We analyzed wh...The Iberian wall lizard Podarcis hispanica forms part of a species complex with several morphologically and geneti- cally distinct types and populations, which may or may not be reproductively isolated. We analyzed whether female mate choice based on males＇ chemical signals may contribute to a current pre-mating reproductive isolation between two distinct populations of P. hispanica from central Spain. We experimentally examined whether females choose to establish territories on areas scent-marked by males of their own population, versus areas marked by males of the other population. Results showed that fe- males did not prefer scent-marks of males from their own population. In contrast, females seemed to attend mostly to among-individual variation in males＇ pheromones that did not differ between populations. Finally, to test for strong premating re- productive isolation, we staged intersexual encounters between males and females. The population of origin of males and females did not affect the probability nor the duration of copulations. We suggest that the different environmental conditions in each population might be selecting for different morphologies and different chemical signals of males that maximize efficiency of communication in each environment. However, females in both populations based mate choice on a similar condition-dependent signal of males. Thus, male signals and female mate choice criteria could be precluding premating reproductive isolation between these phenotypically ＂distinct＂ populations [Current Zoology 59 （2）： 210-220, 2013].展开更多
We tested the role of interspecific competition in driving species distribution at multiple spatial scales using two sibl- ing species of Galerida larks （G cristata and G. theklae） in Morocco （sympatry）, Balearic ...We tested the role of interspecific competition in driving species distribution at multiple spatial scales using two sibl- ing species of Galerida larks （G cristata and G. theklae） in Morocco （sympatry）, Balearic islands （G theklae only） and Israel （G cristata only）. We first investigated regional-scale determinants by contrasting allopatric versus sympatric patterns in five distinct habitat types. We next focused on a single habitat used by both species, the coastal sand dunes. Dune quadrats were established along the Moroccan coast and completed by a quadrat in the nearest distinct landscape habitat. Poisson regressions were used to model Galerida counts together with ecological predictors as concerns the climate, topography, vegetation structure and soil gra- nulometry. At the local scale, both species preferred grey dunes over white sand dunes, and both were negatively affected by the abundance of the congeneric species in the dune. However, we found that G theklae tended to replace G. cristata in more arid sand dunes, even if the transition was not strictly clinal. Instead, the transition occurred when the surrounding landscape changed from coastal wetlands to bathas （grasslands with shrubs）, highlighting the importance of habitat composition at the landscape scale. The fact that G cristata used bathas in allopatry, but not in sympatry, suggested that the competitive environment contri- buted to determine sand dune occupancy. We suggest that landscape-level effects may be pivotal in explaining species distribu- tion not only at the local scale, by affecting the pool of potential immigrants, but also at the regional scale, by contributing to species＇ range limit [Current Zoology 61 （1）： 10-22, 2015].展开更多
The mechanisms responsible for species replacement during ecological successions is a long-standing and open debate. In this study, we examined the distribution of the Sardinian warbler Sylvia melanocephala along two ...The mechanisms responsible for species replacement during ecological successions is a long-standing and open debate. In this study, we examined the distribution of the Sardinian warbler Sylvia melanocephala along two grassland-to-forest gradients, one in a high-diversity area （Albera-Aspres chain in Catalonia： eight Sylvia warbler species） and one in a low-diversity area （Mount Hymittos in Greece： four species）. In Catalonia, distribution models suggested that the apparent exclusion of S. melanocephala from the open and forest ends of the gradient may be explained entirely by the preference of S. melanocephala for mid-successional shrublands. However, a joint analysis of both data sets revealed that： 1） S. melanocephala was more evenly dis- tributed along the vegetation gradient in Greece, suggesting ecological release in the low-diversity area; and 2） a distribution model assuming interspecific competition （based on the distribution of Sylvia species showing a negative co-occurrence pattern with S. melanocephala） had a significantly higher predictive ability than a distribution model based on habitat variables alone. Our study supports the view that species turnover along ecological gradients generally results from a combination of intrinsic preferences and interspecific competition [Current Zoology 57 （3）： 307-317, 2011].展开更多
Seabirds are good candidates as ecological indicators, especially in under-studied ecosystems since they provide insights into marine ecosystem processes and functions at various trophic levels. Our review discusses s...Seabirds are good candidates as ecological indicators, especially in under-studied ecosystems since they provide insights into marine ecosystem processes and functions at various trophic levels. Our review discusses salient points on the present status of seabirds in the Bay of Bengal Large Marine Ecosystem;despite overall low seabird numbers and biomass, this region harbors 9 species of terns, one of the most threatened bird group worldwide, which are known to breed in various marine habitats of Andaman and Nicobar islands, in addition to the coastal areas of mainland. Further, we elaborate on employing seabirds as potential indicators of this ecosystem and how they outscore other taxa in this aspect. Finally, we argue that it is essentially to fill the gaps in our knowledge about the BOBLME, mainly about the interplay between seabirds, climate change and fisheries.展开更多
This study endeavour assesses agromorphological likeness between initial introductions and regenerated accessions at the International Coconut Genebank for Africa and the Indian Ocean (ICG-AIO) based in C?te d’Ivoire...This study endeavour assesses agromorphological likeness between initial introductions and regenerated accessions at the International Coconut Genebank for Africa and the Indian Ocean (ICG-AIO) based in C?te d’Ivoire. Ten couples of parental (G0) and regenerated (G1) accessions of Tall coconut palms were analyzed using Principal Component Analysis (PCA) and Multiple Analysis of Variance (MANOVA) from 26 agromorphological characters. The main results showed a relative decrease in the expression of the phenotypical traits concerning the component of the fruit, height and vigor of the stem and yield of bunches and fruits after one regeneration cycle. But, a high proportion (69%) of studied characters from leaf, inflorescence and nut components showed likeness between G0 and G1 accessions. After one regeneration cycle, the controlled pollination method guarantees significant conservation of the expression of the majority of agromorphological traits. Consequently, regenerated accessions of Tall coconut palms can be used to pursue research and development programs in C?te d’Ivoire.展开更多
文摘The Iberian wall lizard Podarcis hispanica forms part of a species complex with several morphologically and geneti- cally distinct types and populations, which may or may not be reproductively isolated. We analyzed whether female mate choice based on males＇ chemical signals may contribute to a current pre-mating reproductive isolation between two distinct populations of P. hispanica from central Spain. We experimentally examined whether females choose to establish territories on areas scent-marked by males of their own population, versus areas marked by males of the other population. Results showed that fe- males did not prefer scent-marks of males from their own population. In contrast, females seemed to attend mostly to among-individual variation in males＇ pheromones that did not differ between populations. Finally, to test for strong premating re- productive isolation, we staged intersexual encounters between males and females. The population of origin of males and females did not affect the probability nor the duration of copulations. We suggest that the different environmental conditions in each population might be selecting for different morphologies and different chemical signals of males that maximize efficiency of communication in each environment. However, females in both populations based mate choice on a similar condition-dependent signal of males. Thus, male signals and female mate choice criteria could be precluding premating reproductive isolation between these phenotypically ＂distinct＂ populations [Current Zoology 59 （2）： 210-220, 2013].
文摘We tested the role of interspecific competition in driving species distribution at multiple spatial scales using two sibl- ing species of Galerida larks （G cristata and G. theklae） in Morocco （sympatry）, Balearic islands （G theklae only） and Israel （G cristata only）. We first investigated regional-scale determinants by contrasting allopatric versus sympatric patterns in five distinct habitat types. We next focused on a single habitat used by both species, the coastal sand dunes. Dune quadrats were established along the Moroccan coast and completed by a quadrat in the nearest distinct landscape habitat. Poisson regressions were used to model Galerida counts together with ecological predictors as concerns the climate, topography, vegetation structure and soil gra- nulometry. At the local scale, both species preferred grey dunes over white sand dunes, and both were negatively affected by the abundance of the congeneric species in the dune. However, we found that G theklae tended to replace G. cristata in more arid sand dunes, even if the transition was not strictly clinal. Instead, the transition occurred when the surrounding landscape changed from coastal wetlands to bathas （grasslands with shrubs）, highlighting the importance of habitat composition at the landscape scale. The fact that G cristata used bathas in allopatry, but not in sympatry, suggested that the competitive environment contri- buted to determine sand dune occupancy. We suggest that landscape-level effects may be pivotal in explaining species distribu- tion not only at the local scale, by affecting the pool of potential immigrants, but also at the regional scale, by contributing to species＇ range limit [Current Zoology 61 （1）： 10-22, 2015].
文摘The mechanisms responsible for species replacement during ecological successions is a long-standing and open debate. In this study, we examined the distribution of the Sardinian warbler Sylvia melanocephala along two grassland-to-forest gradients, one in a high-diversity area （Albera-Aspres chain in Catalonia： eight Sylvia warbler species） and one in a low-diversity area （Mount Hymittos in Greece： four species）. In Catalonia, distribution models suggested that the apparent exclusion of S. melanocephala from the open and forest ends of the gradient may be explained entirely by the preference of S. melanocephala for mid-successional shrublands. However, a joint analysis of both data sets revealed that： 1） S. melanocephala was more evenly dis- tributed along the vegetation gradient in Greece, suggesting ecological release in the low-diversity area; and 2） a distribution model assuming interspecific competition （based on the distribution of Sylvia species showing a negative co-occurrence pattern with S. melanocephala） had a significantly higher predictive ability than a distribution model based on habitat variables alone. Our study supports the view that species turnover along ecological gradients generally results from a combination of intrinsic preferences and interspecific competition [Current Zoology 57 （3）： 307-317, 2011].
文摘Seabirds are good candidates as ecological indicators, especially in under-studied ecosystems since they provide insights into marine ecosystem processes and functions at various trophic levels. Our review discusses salient points on the present status of seabirds in the Bay of Bengal Large Marine Ecosystem;despite overall low seabird numbers and biomass, this region harbors 9 species of terns, one of the most threatened bird group worldwide, which are known to breed in various marine habitats of Andaman and Nicobar islands, in addition to the coastal areas of mainland. Further, we elaborate on employing seabirds as potential indicators of this ecosystem and how they outscore other taxa in this aspect. Finally, we argue that it is essentially to fill the gaps in our knowledge about the BOBLME, mainly about the interplay between seabirds, climate change and fisheries.
文摘This study endeavour assesses agromorphological likeness between initial introductions and regenerated accessions at the International Coconut Genebank for Africa and the Indian Ocean (ICG-AIO) based in C?te d’Ivoire. Ten couples of parental (G0) and regenerated (G1) accessions of Tall coconut palms were analyzed using Principal Component Analysis (PCA) and Multiple Analysis of Variance (MANOVA) from 26 agromorphological characters. The main results showed a relative decrease in the expression of the phenotypical traits concerning the component of the fruit, height and vigor of the stem and yield of bunches and fruits after one regeneration cycle. But, a high proportion (69%) of studied characters from leaf, inflorescence and nut components showed likeness between G0 and G1 accessions. After one regeneration cycle, the controlled pollination method guarantees significant conservation of the expression of the majority of agromorphological traits. Consequently, regenerated accessions of Tall coconut palms can be used to pursue research and development programs in C?te d’Ivoire.
