Degraded forest areas studied in Anamalai Hills recovered significantly in terms of numbers of trees and species
All in 14 years: A degraded fragment in the Anamalai Hills (left) with with invasive weeds removed in preparation for restoration planting in 2004, and the same site in 2018 (right) showing some recovery of rainforest trees. NCFNCF
A two-decade long study carried out by ecologists from Nature Conservation Foundation and University of Columbia finds that active restoration can promote recovery of tropical rainforest fragments with seven to 15 years of effort.
The recovery included improvement in forest structure and composition as well as carbon storage. Further, the study finds that such a restoration effort would be more effective in fragmented forest patches. For example, those found in the middle of plantations, rather than in areas where the forest is contiguous but degraded. The results of the study are published in the open-access journal Ecosphere.
The study, which began in 2002, focused on rainforests fragments in Anamalai Hills, in the Western Ghats, and the ecological restoration involved clearing the chosen areas of invasive weeds and planting a diverse mix of native species. “We planted more than 150 native rainforest tree species overall. Depending on size of the plot, we planted between 27 and 82 native species carefully selected as appropriate for the site,” says T. R. Shankar Raman, from NCF and an author of the paper.
The group studied 25 pairs of plots within degraded forest fragments. In one of the pair of plots, they carried out active restoration which included first removing non-native weeds and then planting saplings belonging to a variety of native tree species.
The other plot was left to regenerate naturally. Finally, the results of the effort on the two sets of plots were compared with 17 benchmark areas that were relatively free of human disturbance in a few decades.
“A key challenge we faced was in identifying suitable pairs of sites such that actively restored and naturally regenerating plots were similar to each other in all respects (for instance, slope, topography, past disturbance), except for that one was restored and the other was not,” says Anand Osuri from The Earth Institute, Columbia University, and first author of the paper, in an email to The Hindu. “We achieved this by conducting detailed site surveys before the main study, comparing old photographs of the sites pre-restoration, and through discussions with our field staff who were involved in the restoration efforts.”
The team found that the actively restored areas improved in comparison with the passively restored ones in a way that matched the benchmarks to a good percentage. From seven to 15 years after restoration, these degraded forests recovered significantly in terms of numbers of trees, 49% in the number of tree species and 47% in the amount of carbon stored for a given area, compared to degraded forests left to recover naturally, according to figures presented in the paper.
“First, don’t assume that planting trees is the best way to restore an ecosystem. Trees should not be planted in ecosystems such as grasslands, deserts, or wetlands that did not have any forests to begin with.” says Divya Mudappa, another author of the paper and from NCF.
According to her, the best way to go about ecological restoration would be to identify critical areas that would benefit from restoration effort — this would include sites far away from larger, contiguous tracts of forests or those that would be critical as animal or plant movement corridors. “Ecological restoration should use a diverse set of local, native species. We need to plan long-term as most of the native plants can be slow-growing and sometimes even difficult to grow,” Dr. Mudappa explains.
With regard to degraded forests that are not isolated, Dr. Shankar Raman says, “If degraded forests adjoin or are near larger tracts of relatively intact forests, it may be better to just protect them and leave them to regenerate naturally as that would be cost-effective.”
Some of the fragments that the team studied were located within tea and coffee plantations. “We were fortunate that tea and coffee plantation companies extended their support. They engaged in partnerships with us, recognised these forest patches as ‘biodiversity plots’ within their estates and provided in-kind support such as labour and space for nursery,” says Dr. Shankar Raman.
It is end-September, and the season for conferences and seminars has started in India. Generally, they invite experts from diverse disciplines in a conference, usually on a broad theme, while in a seminar, it is experts in a given discipline or even sub- disciplines, who exchange and critique ideas for collaborations, and thus, hopefully, advance the field. A typical attendee in conferences gets to hear lectures from a field that may not be familiar to him/her and thus has a learning opportunity. In a theme-special seminar, the attendee is a part-player in the game, has a broad familiarity with the theme and gets to listen to various nuances, some of which he learns, appreciates and gains from. Thus, conferences and seminars are useful.
Jump in nodders
However, there is one downside to this and that is this business of some or many in the audience nodding off their heads and taking naps while the presentation on the stage is on. Why do they do it, how often does this happen, what the “risk factors” for are such nodding off have been summarised in a 15-year-old publication by K. Rockwood et al., in the Canadian Medical Association Journal, Dec 7, 2004 issue (DOI:10.1503/emaj.1041570). In this humorous and satirical paper, they talk about how they conducted a surreptitious, prospective cohort study to examine how often physicians nod off during scientific meetings and to examine the risk factors for such nodding off. In a two-day lecture series, attended by 120 people, they found that the number of nodding off events per lecture (NOELs) per 100 attendees jumped to about 10 for a 15-20 minute lecture to over 22 or so when the lecture goes on for 30-40 minutes or more; the longer the lecture the greater the NOELs. They further ensured that “nodding off” is different from “nodding in agreement (NIA)” by the attendee who appreciated the point made by the speaker (nodding here was different in amplitude, the timing and the frequency).
Why did this happen? What are the risk factors? Several factors came to light. These were environmental factors (such as dim lighting, room temperature, comfortable seating), audiovisual (poor slides, not speaking into the microphone), circadian (early morning hours, postprandial or after a good breakfast or lunch) and “speaker-related” (speaking in a monotonous tone, boring direction). [Today, cell phones and mini-laptops are carried by most, if not all members in the audience. While the organisers announced ahead of the lectures that cell phones be switched off, or put on silent mode, the numbers of NOEL has probably come down as the attendee loses interest in the speech and moves to his/her phone or the computer on hand . If however the announcer insists that these be put off during the sessions, the NOELs will increase!].
The authors then accosted the NOEL people in the audience and politely asked them why they nodded off. First of all, when a nodder was told he was not alone, but many others did same too, most of them were reassured to know that it was not their individual fault! When asked whether he/she is likely to attend such a lecture again, some of them said yes, they always needed a nap; some others said yes they will if they are paid , and some would rather have their “teeth grilled” than attend! And finally, when asked whose fault led to nodding off, most said that it was entirely the speaker’s fault, and only a few said the fault was theirs!
What are the take-home lessons for speakers? How does he/she capture sustained interest in the audience? They cannot avoid dimly lit room, since the speaker uses slides, presentations and short videos. But a useful tip comes from a recent report in the literature. It says that the ideal lecture should have 37% text, 29% diagrams/figures and 33% videos. It would worth putting this fractionation into practice and see how it works. And in text slides (or presentations), it is best to stick to the “aspect ratio” (five units width and three units height of the image or text), large fonts so that reading the text is easy, and colour contrast between the background and text ( black or light blue background and a contract colour text). In addition, speak slow and clear and into the microphone (see the paper by Lim et al., from Singapore, titled “Sustaining interest during lectures with the use of multimedia”, Med.edu.online 2006, available from http://www.med-ed-online.org.
Finally, the brain-biology behind this has become better understood, as a recent publication from a team of Japanese and Chinese scientists has shown. They point out that the part known as the nucleus accumbens in the brain has a strong ability to induce a nap by activating a set of molecules called the A2A receptors. The main triggering molecule here is adenosine which activates the A2A receptor and induces sleep (Y. Oishi et al., Nature Communication 2017:8(1) DOI: 10.1038/S41467-017-00781-4). Besides adenosine there are other somnogenic molecules, which act on the A2A receptor as well. Popular sleep-inducing drugs potentiate the A2A receptor and put you to sleep. On the contrary, caffeine in coffee and tea block the receptor and keep you awake.
So next time you attend a lecture drink a cup of coffee before and keep awake, And when you give a lecture, follow the instructions of Lim and others from Singapore.
Indian adolescents’ performance in maths, reading, vocabulary was affected, a study finds
Preventive move: Expanding the mid-day meal scheme to include breakfast for children at risk of food insecurity may prevent impact of hunger on child cognition. G. MoorthyG_Moorthy
With the introduction of Sarva Shiksha Abhiyan and the mid-day meal scheme, there has been an increase in the number of children enrolling in schools. But new research says that Indian children are not able to perform well in their studies due to widespread food insecurity at home.
An international team from U.K. and India looked at data collected by Young Lives, a UK- and India-based research study of over 1,900 schoolchildren in Andhra Pradesh and Telangana.
The team examined how the experience of food insecurity at home at ages 5, 8 and 12 years affected children’s performance in studying maths, reading the local language, vocabulary skills and English ability in adolescence (12 years old).
The study published in Economics of Education Review shows that children whose families struggled with their food needs during different stages of childhood performed less well in all the four tests in adolescence compared to their peers.
The link between food insecurity at home and learning was more pronounced for those children who experienced chronic food insecurity and/or experienced it during early childhood (at 5 years).
Further, transitory spells of food insecurity at home did not affect the kids’ test scores in reading and vocabulary, but their mathematical skills were still affected. This suggests that children may be able to bounce back from short-term food insecurity in some learning domains, but not in others.
The researchers ask for early intervention from the government. “Because some curriculum is cumulative, it may be difficult for children who experience childhood food insecurity to catch up on learning later,” explains Dr. Elisabetta Aurino, from Imperial College Business School, London, and the lead author of the work, in an email to The Hindu. She adds that teaching at the right level and remedial education programmes can also help children who have fallen behind to catch up with peers.
“Studies have shown that mid-day meal schemes can improve learning and classroom effort. Expanding this programme to include breakfast for children at higher risk of food insecurity or in the lean season may prevent hunger and its negative repercussions on child cognition,” she adds.
“Our findings highlight how even very early experiences of food insecurity can have a lasting impact on outcomes across the life course,” one of study authors Dr. Jasmine Fledderjohann, from Lancaster University adds.
Dr. Sukumar Vellakkal from BITS Pilani KK Birla,Goa Campus says, “Increased budget allocation and effective implementation of the Integrated Child Development Services programme would be also welcome. Also, the nutritional value needs to be enhanced. Community kitchens for provisioning free food for needy populations are another initiative worth considering in this regard, which could be provisioned and run through local bodies.” He is one of the authors of the paper.
Impact on economy
The researchers add that experiencing food insecurity at home during childhood can affect India’s economy through lower human capital accumulation. “There are plenty of economic studies that show that countries with better-educated workforces are more capable of innovating and grow at a faster pace than countries with lower human capital stock. If children from food-insecure households tend to learn less at school, a country is not reaching its potential in terms of human capital, thus hampering its economic performance,” adds Dr. Aurino.
As this is a study on a very small population, the team suggests regular surveys that measure food insecurity among households with children across the whole of India are needed, as this will allow for tracking the state of household food insecurity over time and devise locally-appropriate remedial measures.
Lack of essential nutrients and increasing salinity were main reasons for decline
Sturdy species: The site of restoration was first stabilised by planting four native, salt-tolerant varieties of grass, says Krishna Ray (left).Special arrangement Special arrangement
Increasing anthropogenic activities along with natural stresses have led to massive degradation of one of India’s World Heritage Site — the Sunderbans. A team of researchers from West Bengal State University, Kolkata, set out with the herculean task of identifying the major reasons for the decline and also devising new restoration strategies. They surveyed 19 shoreline mangrove patches, collected soil and water samples and studied them. The results published in Hydrobiologia highlight that lack of essential nutrients and increasing salinity were the main problems in Sunderbans.
Cause of decline
“Nutrient depletion especially phosphorus and nitrogen was found to be directly connected with the decline in forest cover. We are now trying to understand what is causing nutrient depletion. We have also planned to expand this analysis to a larger area, so as to cover the whole mangrove region and get a complete picture,” says Rajojit Chowdhury, Ph.D. scholar at the university and the first author of the paper.
They also saw a change in the species distribution — salt-sensitive ones such as Heriteira fomes, Xylocarpus species and Phoenix paludosa were not able to cope up with the increase in the salinity and declined while the tolerant varieties thrived.
After understanding the state of the degraded region, the team started the bio-restoration process. “We initially stabilised the site of restoration by planting four native salt-tolerant varieties of grass. These grasses proved to exhibit the highest survival in the lower and middle intertidal zone. During the last five years (2014–2019) almost about one-hectare area of the degraded patch has been restored by the growth of these grasses,” explains Krishna Ray, team leader of the Environmental Biotechnology Group of the university and corresponding author of the work.
The grass rhizosphere also provided a nutritive atmosphere to the colonizing mangroves because this root zone decomposes microbes and helps release more nutrients in the mudflat soil. In addition, these grasses also provided protection from high energy waves and subsequent erosion of soil. The team also used native plant growth-promoting bacteria to enrich the degraded land.
Route to restoration
The team then established an on-site mangrove nursery and during each season collected mangrove propagules or buds and maintained in the nursery till transplantation. About 22 species of mangroves were restored in the region which included threatened, endangered and vulnerable species. High salt-tolerant varieties were planted near the shoreline and the moderate ones farther. The team notes that the present ecosystem in the studied patch is almost brought back to the original pristine condition.
“We have already identified many degraded mangrove patches in the western part of Indian Sundarbans and have planned to restore them by the application of this technology,” adds Prof. Ray.
Researchers at the Centre for Nano Science and Engineering at the Indian Institute of Science (IISc), Bengaluru, have developed a technique to trap and move tiny objects in the nanoscale using optical “tweezers” employing light. This is a tool that can be used to pick and move small suspended particles even including cells. This research has been published in Nature Communications.
Optical tweezers have been known for about thirty years now ; however, they have a limitation when it comes to nanosized particles. This was partly solved with the development of “plasmonic tweezer” which works on the principle that when a disc of noble metal, like gold, is illuminated with light, it creates an electromagnetic field around the disc. This field can attract and hold on to tiny particles.
Plasmonic tweezers are fixed in space and can therefore only trap objects that come close to them. Though the team, in an earlier work, showed that such plasmonic tweezers could be manoeuvred with a combination of light and magnetic fields, they could not apply the technique to some types of colloids.
In the present work, they overcome this limitation by developing a method that uses only optical force. They integrate a silver nanodisc with a microrod made of glass and the combination can be manipulated using laser beams alone. This “tweezer-in-a-tweezer” approach can trap objects of about 40 nanometres in size, using a single laser beam. This is the typical size of a virus or DNA. “The optical tweezer holds the plasmonic tweezer and the plasmonic tweezers trap our target nanoparticles, therefore tweezer (plasmonic) in tweezer (optical),” says Souvik Ghosh, first author of the paper.
“The technique is ready for real world applications,” says Prof. Ambarish Ghosh, in whose lab the research was carried out. “Simplicity and ease of implementation are the biggest USPs for this device. It is patented and we are already in discussion with a company for licensing.”