species replacement
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2021 ◽  
Vol 20 (2) ◽  
pp. 139-150
Author(s):  
Angel Ivan Contreras-Calvario ◽  
Abigail Mora Reyes ◽  
Rene Avalos Vela ◽  
Jorge L. Castillo Juárez ◽  
M. Delia Basanta

The central mountain region of Veracruz is one of the richest areas of herpetofauna in Mexico. The steep topographic gradient of this region is associated with climatic gradients that enable the occurrence of highly diverse herpetofauna communities. We tested differences among habitats to herpetofauna in an urban area, pine forest, oak forest, and riparian forest of municipality Camerino Z. Mendoza, Veracruz, Mexico. We conducted two-day monthly surveys between 2015 and 2017 in 69 sites from fragments of an urban area, riparian forest, Quercus forest, and Quercus-Pinus forest and tested for differences in herpetofauna species among these fragments. We found a total of 11 amphibian and 33 reptile species, and a high composition dissimilarity and species replacement among the sites. Our results amplified significantly the species-records within Camerino Z. Mendoza, and showed a great variation of amphibian and reptile composition among sites, highlighting the current role of these forests as a reservoir for herpetofauna and their importance for future conservation strategies in the region.


New Forests ◽  
2021 ◽  
Author(s):  
Andrea N. Brennan ◽  
Zhao Ma ◽  
Douglass F. Jacobs

AbstractHybridization and genetic modification are potential methods for incorporation of stress tolerance being explored to support some at-risk tree species. However, many concerns, both ecological and economic, have been identified in using these biotechnologies, such as potential for invasiveness or high cost. There is limited information on perceptions towards hybrid and genetically modified (GM) trees, particularly from individuals responsible for widescale tree management. An online survey was administered to land managers in Indiana, USA to gauge perceptions to hybrid and GM trees, and current hybrid tree use. Land managers had stronger concern for ecological, rather than economic, issues, with potential for invasiveness being strongest. Agreement was highest for using the tree types for conservation and restoration of at-risk species and production purposes. However, perceptions varied by characteristics such as concern type, age, and land type managed. Ecological concern and land type managed most strongly predicted hybrid use. Overall, the majority of land managers agreed, rather than disagreed, with a variety of potential hybrid and GM tree advantages and purposes. Thus, results indicate that if these biotechnologies are deemed appropriate for supporting at-risk species, the majority of land managers in Indiana might be agreeable to such recommendations from researchers. However, it was also clear that despite this, most respondents concurrently had strong ecological concerns about suitability as a native species replacement. To address this, it is essential that these tree types be thoroughly vetted, and land managers be actively engaged in the process, as this population would ultimately be responsible for any widescale implementation of hybrid and GM trees.


Author(s):  
Robin J. Pakeman ◽  
Debbie A. Fielding

AbstractMany ecosystems are grazed by livestock or large, wild herbivores and exist as mosaics of different vegetation communities. Changing grazing could have an impact on heterogeneity as well as on composition. A long-term, large-scale grazing experiment that maintained existing low-intensity sheep grazing, tripled it, removed it and partially substituted sheep grazing by cattle grazing was set up on a mosaic of upland vegetation types. The impact of changing grazing regimes was assessed in terms of changes in temporal and spatial species and functional beta diversity. Removal of grazing had the highest impact on species replacement, whilst increased grazing was closest to maintaining the original species complement. Wet heath and Molina mire had the lowest turnover, but wet heath showed the highest changes in unidirectional abundance as it contained species capable of increasing in abundance in response to changing grazing intensity. Agrostis-Festuca and Nardus grasslands displayed the highest level of balanced species replacement reflecting their more dynamic vegetation. In functional terms, there was no clear separation of communities based on their grazing preference, all were relatively resistant to change but Nardus grassland was the most resistant to the removal of grazing. The increased offtake associated with increased grazing led to a degree of homogenisation as grazing tolerant species associated with preferred communities increased in the unpreferred ones. Decisions about grazing management of the uplands involve many trade-offs, and this study identified potential trade-offs between stability and homogenisation to add to existing ones on the biodiversity of different groups of species and on ecosystem services.


Insects ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 936
Author(s):  
Jan Peter Reinier de Vries ◽  
Emiel van Loon ◽  
Paulo A. V. Borges

We present an analysis of arthropod diversity patterns in native forest communities along the small elevation gradient (0–1021 m a.s.l.) of Terceira island, Azores (Portugal). We analysed (1) how the alpha diversity of Azorean arthropods responds to increasing elevation and (2) differs between endemic, native non-endemic and introduced (alien) species, and (3) the contributions of species replacement and richness difference to beta diversity. Arthropods were sampled using SLAM traps between 2014 and 2018. We analysed species richness indicators, the Hill series and beta diversity partitioning (species replacement and species richness differences). Selected orders (Araneae, Coleoptera, Hemiptera and Psocoptera) and endemic, native non-endemic and introduced species were analysed separately. Total species richness shows a monotonic decrease with elevation for all species and Coleoptera and Psocoptera, but peaks at mid-high elevation for Araneae and endemic species. Introduced species richness decreases strongly with elevation especially. These patterns are most likely driven by climatic factors but also influenced by human disturbance. Beta diversity is, for most groups, the main component of total (gamma) diversity along the gradient but shows no relation with elevation. It results from a combined effect of richness decrease with elevation and species replacement in groups with many narrow-ranged species.


Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1447
Author(s):  
Juan Diego Gilbert ◽  
Inmaculada de Vicente ◽  
Fernando Ortega ◽  
Francisco Guerrero

Temporary Mediterranean wetlands are characterized by both intra and interannual variations in their environmental conditions. These inherent fluctuations in limnological features affect the seasonal variation in the structure and dynamics of the aquatic communities. In this study, we hypothesized that zooplankton community is coupled to seasonal changes of the environmental variables along the hydroperiod. To get this purpose, the study was focused in monitoring, by collecting monthly samples during an annual period, seven temporary Mediterranean ponds located in the south-eastern region of the Iberian Peninsula (Alto Guadalquivir region, Andalusia). The relationships between zooplankton community and the different limnological variables were analyzed based on two approaches: a Spearman correlation analysis and a correspondence canonical analysis (CCA). The results have shown that chlorophyll-a concentration, Secchi depth, total nitrogen concentration, wetland area and depth were the variables with a greater influence on the zooplankton community, explaining the zooplankton species replacement. Moreover, optima and tolerance of the zooplankton species were obtained from the position of species within CCA diagram, allowing the separation of different groups of zooplankton along the hydroperiod. We finally highlight that the monitoring of zooplankton community and environmental conditions are necessary to evaluate how theses singular and endangered aquatic ecosystems will be affected by anthropogenic activities in the future.


2020 ◽  
Author(s):  
Julia López‐Delgado ◽  
Isolde van Riemsdijk ◽  
Jan W. Arntzen
Keyword(s):  

2020 ◽  
Vol 10 (23) ◽  
pp. 8372
Author(s):  
Giuseppina Anna Corrente ◽  
Sante Cospito ◽  
Agostina Lina Capodilupo ◽  
Amerigo Beneduci

Electrochromic devices (ECDs) that allow the modulation of light transmission are very attractive in the research field of energy saving. Here all-in-one gel switchable ECDs based on mixed-valence electroactive compounds were developed. The use of the thienoviologen/ferrocene couple as cathode and anode, respectively, leads to a significant electrochromic band in the visible range (550–800 nm), with a color change from yellow to green, and to a lower band in the NIR region (1000–1700 nm), due to the presence of one electroactive-chromic species. Replacement of the electroactive ferrocene with a fluorene-diarylamine electroactive-chromic species, allows to extend and intensify the absorption in the NIR region, thus affording modulation of the solar radiation from 500 up to 2200 nm. High optical contrast, fast coloration and bleaching times and outstanding coloration efficiencies were measured for all observed absorption bands upon the application of small potential differences (1.4 V < DV < 2 V).


Trees ◽  
2020 ◽  
Author(s):  
R. J. Mitchell ◽  
R. L. Hewison ◽  
R. K. Haghi ◽  
A. H. J. Robertson ◽  
A. M. Main ◽  
...  

2020 ◽  
Author(s):  
Gilberto Nicacio ◽  
Erlane José Cunha ◽  
Neusa Hamada ◽  
Leandro Juen

AbstractWe investigated how components of beta diversity (i.e., the turnover and nestedness and functional compositional) aquatic insect assemblages change among sites and are influenced by environmental and spatial drivers. For this, we analyzed beta-diversity and functional composition of Ephemeroptera, Plecoptera, and Trichoptera in 16 streams in two Amazonian basins with distinct environmental conditions (the Carajás and Tapajós regions). We performed Multiple regression on dissimilarity matrices (MRM) and Procrustes analysis to test spatial and environmental influences on the taxonomic and functional composition of communities. Community dissimilarity was most related to variations in geographic distance and topography, which highlighted the environmental distances shaping the communities. Variation in functional composition could be mostly attributed to the replacement of species by those with similar traits, indicating trait convergence among communities. Environmental predictors best-explained species replacement and trait congruence within and between the regions evaluated. In summary, among communities with different taxonomic compositions, the high species replacement observed appears to be leading them to have similar community structure, with species having the same functional composition, even in communities separated by both small and large geographic distances.


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