Salt and Water Stress Responses in Plants

Climate change-driven ecological disturbances have a great impact on freshwater availability which hampers agricultural production. Currently, drought and salinity are the two major abiotic stress factors responsible for the reduction of crop yields worldwide. Increasing soil salt concentration decreases plant water uptake leading to an apparent water limitation and later to the accumulation of toxic ions in various plant organs which negatively affect plant growth. Plants are autotrophic organisms that function with simple inorganic molecules, but the underlying pathways of defense mechanisms are much more complex and harder to unravel. However, the most promising strategy to achieve sustainable agriculture and to meet the future global food demand, is the enhancement of crop stress tolerance through traditional breeding techniques and genetic engineering. Therefore, it is very important to better understand the tolerance mechanisms of the plants, including signaling pathways, biochemical and physiological responses. Although, these mechanisms are based on a well-defined set of basic responses, they can vary among different plant species.

WORM BIOMASS AND VERMICOMPOST PRODUCTION BY THE EPIGEIC EARTHWORM, PERIONYX EXCAVATUS BY USING DIFFERENT ORGANIC WASTES

As the epigeic earthworms are known to be efcient and potential biodegrades and nutrient releasers, tolerant to wide range of ecological disturbances, aids in litter communication and efcient decomposers. Therefore, the present study was undertaken to nd out the inuence of various organic wastes (such as False Ashoka waste-FAW (Polyalthia longifolia), Parthenium wastePW (Parthenium hysterophorus), Cotton residue waste-CRW (Gossypium), Lawn grass waste-LGW (Agrostis) and Cattle manure-CM) on the production of worm biomass and vermicompost by the epigeic earthworm, Perionyx excavatus along with control compost experiments without worms (in triplicates) to know the potentiality of this worm species in processing of various organic wastes for the production of worm biomass as vermiprotein and vermicompost as biofertilizer. Both compost and vermicompost experimental pots were terminated after 35 and 70 days time intervals. Observations were made with respect to number of old and new adult worms, new sub-clitellates, juveniles, cocoons with their weight were noted to determine the total worm biomass (Gross biomass), biomass ratio (WBR) and Fold Increase in Worm Number (FIWN). Percent compost and vermicompost produced out of different organic waste were also calculated at the end of each experiment at35 and 70 days. The results of the present study revealed that the biomass of Perionyx excavatus such as Gross worm biomass (GWB), Worm biomass ratio (WBR) and Fold increase in worm number (FIWN) increased from 35days to 70 days time intervals in all the organic wastes (FAW, PW, CRW, LGW and CM). It was maximum in CM and minimum in FAW among all the organic wastes. There is a signicant variation was noticed in worm biomass production (GWB, WBR, and FIWN) among and between all the organic wastes except between few organic wastes at 35 and 70 days time intervals. The vermicompost production was more as compared to normal compost in all the organic wastes. Further, both compost and vermicompost production were more in CM followed by LGW, CRW, PW and minimum in FAW among all organic wastes. The signicant difference was also observed in the production of compost and vermicompost among and between different organic wastes except between few organic wastes at different time intervals. Based on the results, it can be concluded that the earthworm, Perionyx excavatus is an efcient epigeic earthworm species, effectively used in vermicomposting for the production of vermicompost and as well as in vermifarming in the production of worm biomass as vermiprotein. Further, earthworm biomass, compost and vermicompost production primarily depends on nature of organic wastes and secondly on the potentiality of earthworm species used in the experimental studies.

Natural disturbances and masting: from mechanisms to fitness consequences

The timing of seed production and release is highly relevant for successful plant reproduction. Ecological disturbances, if synchronized with reproductive effort, can increase the chances of seeds and seedlings to germinate and establish. This can be especially true under variable and synchronous seed production (masting). Several observational studies have reported worldwide evidence for co-occurrence of disturbances and seed bumper crops in forests. Here, we review the evidence for interaction between disturbances and masting in global plant communities; we highlight feedbacks between these two ecological processes and posit an evolutionary pathway leading to the selection of traits that allow trees to synchronize seed crops with disturbances. Finally, we highlight relevant questions to be tested on the functional and evolutionary relationship between disturbances and masting. This article is part of the theme issue ‘The ecology and evolution of synchronized seed production in plants’.

The new face of large dams in the 21st century

Alerted by increasing water insecurity and energy demand, countries, mainly in the Global South, are building dams of unprecedented magnitude. Hundreds of large dams (≥ 100 metres) have been constructed since 2000, with hundreds more under construction. Analyses of the physical attributes of these dams present a concerning image. While they create expansive reservoirs with large surface areas, they have inefficient surface area-to-volume ratios ('S2VR'). Their unprecedented size and the reservoirs’ expansive surface area, indicate severe environmental costs, mainly through ecological disturbances to the (riverine) aquatic ecosystems; and greenhouse gas emissions (GHG). Other ecological costs due to the larger S2VR include a high evaporation rate and compromised biodiversity of a wider area, both up- and downstream. The safety and environmental aspects of these large dams should be robustly scrutinised.

Beyond acedia and wrath: life during the climate apocalypse

In a time when climate change and other ecological disturbances wreak havoc upon both human and natural “households,” how can the people of God respond beyond anger and acedia, or sloth? Easy as it is to be paralyzed by the magnitude of the problems, and tempting as it is to resort to anger and blame, could we follow the prodigal son in “returning to ourselves” and being restored to our rightful place in the household of God? The authors’ experiences with the River of Life Pilgrimage and Church of the Woods provide concrete examples of how the human members of the Body of Christ can be restored to kinship with our non-human sisters and brothers in Christ through immersion, song, praise, and sharing of bread and wine.

Body size, habitat quality, and territory defense in Bachman’s sparrow

Many wild populations of animals conform to the ideal despotic distribution (IDD) in which more competitive individuals exclude less competitive individuals from high quality resources. Body size and aggressiveness are two important traits for resource defense, and they positively covary so that larger individuals are usually more aggressive. Using Bachman’s sparrows, we tested the hypothesis that larger birds are more aggressive and are thus able to compete for the best quality territories. We found that larger males were more aggressive, and more aggressive birds fledged at least one young. However, we did not find consistent relationships between aggressiveness and habitat characteristics. Our results suggest that Bachman’s sparrows meet most of the predictions of the IDD. Frequent ecological disturbances, such as fires, might disrupt the IDD or make it difficult to detect. Additional studies are needed to test for relationships between ecological disturbances and territorial behaviour.

Exploring the natural origins of SARS-CoV-2

SummaryThe lack of an identifiable intermediate host species for the proximal animal ancestor of SARS-CoV-2 and the distance (~1500 km) from Wuhan to Yunnan province, where the closest evolutionary related coronaviruses circulating in horseshoe bats have been identified, is fueling speculation on the natural origins of SARS-CoV-2. Here we analyse SARS-CoV-2’s related bat and pangolin Sarbecoviruses and confirm horseshoe bats, Rhinolophus, are the likely true reservoir species as their host ranges extend across Central and Southern China, and into Southeast Asia. This would explain the bat Sarbecovirus recombinants in the West and East China, trafficked pangolin infections and bat Sarbecovirus recombinants linked to Southern China, and the recently reported bat Sarbecovirses in Cambodia and Thailand. Some horseshoe bat species, such as R. affinis seem to play a more significant role in virus spread as they have larger ranges. Recent ecological disturbances as a result of changes in meat sources could explain SARS-CoV-2 transmission to humans through direct or indirect contact with infected wildlife, and subsequent emergence towards Hubei in Central China. The only way, however, of finding the animal progenitor of SARS-CoV-2 as well as the whereabouts of its close relatives, very likely capable of posing a similar threat of emergence in the human population and other animals, will be by (carefully) increasing the intensity of our sampling.

The Ecology of Disturbance Interactions

Global change has been accompanied by recent increases in the frequency and intensity of various ecological disturbances (e.g., fires, floods, cyclones), both natural and anthropogenic in origin. Because these disturbances often interact, their cumulative and synergistic effects can result in unforeseen consequences, such as insect outbreaks, crop failure, and progressive ecosystem degradation. We consider the roles of biological legacies, thresholds, and lag effects responsible for the distinctive impacts of interacting disturbances. We propose a hierarchical classification that distinguishes the patterns and implications associated with random co-occurrences, individual links, and multiple links among disturbances that cascade in chains or networks. Disturbance-promoting interactions apparently prevail over disturbance-inhibiting ones. Complex and exogenous disturbance cascades are less predictable than simple and endogenous links because of their dependency on adjacent or synchronous events. These distinctions help define regional disturbance regimes and can have implications for natural selection, risk assessment, and options for management intervention.

How influential are squamate reptile traits in explaining population responses to environmental disturbances?

Context Understanding how organismal attributes influence sensitivity to environmental perturbations is a central theme in ecology and conservation. Certain traits, such as body size, habitat use, dietary preference and reproductive output are considered important determinants of animal species’ responses to the impacts of ecological disturbances. However, the general relationships between functional traits and post-disturbance responses by animals are not fully understood. AimsOur primary aim was to use a meta-analysis to evaluate the influence of species traits on variation in population abundances of squamate reptiles (i.e. lizards and snakes). MethodsWe extracted data from 107 original published studies, from which 1027 mean effect sizes of post-disturbance responses by 298 species were estimated. We examined short-term responses only (i.e. within 3 years since the most recent disturbance). A comprehensive range of disturbances was examined, such as habitat destruction, fragmentation, fire, and exotic-species invasions. We used Bayesian linear mixed-effect modelling (BLMM), utilising the Markov-chain Monte Carlo algorithm (MCMC) for the meta-regression. Specifically, we tested the influence of eight species traits (body size, diet, temporal activity pattern, sociality, reproductive mode, clutch size, habitat selection, and mean body temperature), along with disturbance type, in explaining variation in species-specific abundance responses of squamate reptiles post-disturbance. Key resultsPost-disturbance abundance responses of squamate species were significantly influenced by two parameters, namely, mean body temperature and clutch size. In general, significant positive responses post-disturbance were observed for species with higher mean body temperatures and a greater clutch size. The type of disturbance had no detectable influence on squamate abundances. The influence of random effects (heterogeneity among studies and species, and broad taxonomic identity) accounted for more of the model variation than did the fixed effects (species traits and disturbance type). ConclusionsCertain species traits exerted some influence on the sensitivities of lizards and snakes to ecological disturbances, although the influence of random effects was very strong. Our findings are likely to be a result of the complexity and idiosyncratic nature of natural abundance patterns among animal species, in addition to the potential confounding effect of methodological differences among studies. ImplicationsThe present study is the first major quantitative synthesis of how species traits influence population-level responses of squamate reptiles to ecological disturbances. The findings can be used to guide conservation efforts and ecological management, such as by prioritising the efforts of mitigation on species that reproduce more slowly, and those with lower body temperatures.