Editorial 1 : India’s open ecosystems facing an unusual threat: encroaching trees
Context
In a study published on June 5 in the journal Global Change Biology, scientists reported that more trees in open ecosystems like savannahs and grasslands have substantially reduced the number of native grassland birds.
Many become one
- Grasslands and savannahs are biodiverse habitats in tropical and temperate regions throughout the world.
- They cover nearly 40% of the earth’s total landmass and are home to many endemic and at-risk species of plants and animals.
- From megaherbivores like elephants, rhinoceroses, and buffaloes in Africa and Asia to grassland birds like the bustards, floricans, and grouse of the Himalayan grasslands and American prairies, open ecosystems have it all. However, we are rapidly losing them.
- Activities threatening them include the conversion of grasslands, intensive agriculture, loss due to erosion, large-scale development projects, and overgrazing.
- But lurking among these usual suspects is also a highly unusual one: trees.
- The increase in tree and shrub cover is called woody encroachment — and it is widespread across most ecosystems.
- Woody encroachment entails the conversion of open habitats to habitats with greater tree cover and/or shrub density.
- The end result is the homogenisation of an ecosystem, meaning a diverse, multi-layered ecosystem turns into a uniform layer of woody plants.
- This is a dire prospect because open ecosystems are characterised by a grassy understory and a scattering of native tree species.
- They are generally maintained by certain natural as well as human activities like grazing and fire, which are called disturbance regimes because they work in tandem to limit the growth of tree species.
- But once these regimes are disrupted, trees have the calm they need to establish themselves and start woody encroachment.
When trees have ill-effects
- A higher concentration of carbon dioxide in the air due to ongoing climate change also encourages deep-rooted woody plants in grasslands to proliferate.
- Increased atmospheric CO2 is likely to promote trees over grasses because the C3 photosynthetic pathway used by trees is preferred under high CO2 conditions.
- Once trees become dominant in a system, they may further suppress grasses through shading and fire suppression.
- Woody encroachment is widespread worldwide. Many studies have unearthed evidence of different drivers of encroachment on different continents.
- Fire suppression and fragmentation dominate in the South American grasslands, whereas more carbon dioxide and variations in rainfall do so in Australia and Africa.
Inside and outside parks
- Closer home, in India, grasslands occur across different climatic regimes: the country’s west sports arid grasslands; floodplain grasslands dot the Himalayan landscape; and the high-altitude Shola grasslands crown the Western Ghats, to name a few.
- In the Himalayan foothills, the tall, wet grasslands are biodiverse habitats inhabited by iconic species such as Indian one-horned rhinoceroses, swamp deer, Bengal floricans, swamp grass babblers, and some other endemic species.
- These grasslands are highly threatened, not least because previous damage has broken them up into fragmented patches in a sea of forests, agriculture, and other human-derived habitats.
- Such fragmentation leaves these patches even more vulnerable than before.
- Most of today’s wet grasslands occur inside protected areas such as national parks and sanctuaries.
- Yet woody encroachment is rampant inside these parks as well. The cover of grassland habitats had shrunk by 34%, while tree cover in these places had increased by 8.7%.
The human hand
- Woody encroachment is a direct result of human-driven factors that are changing the disturbance regimes open ecosystems need to thrive.
- The suppression of the practices grasslands need to thrive stems from colonial conservation and management policies.
- Colonial officers in tropical countries were known to regard open ecosystems as “wastelands” because they took up space in which trees could grow instead and provide timber.
- The classification allowed these habitats to be converted to plantations as well as provided ground for the colonial government to criminalise communities that practised grazing and fire management.
- Succession of woody species changes the soil conditions, which changes the grass species and faunal association.
- Woody species invite increased predation, especially of the specialist birds’ nests.
- For similar reasons, woody encroachment brought down the population of grassland specialist rodents in the Banni grasslands of Kutch.
- These species also incurred a survivability penalty: the grass allowed them to hide from predators, but as trees cropped up, they spent more time keeping vigil and less time feeding.
An invasion by trees
- Woody encroachment in grasslands has also received a leg-up from large-scale tree plantation programmes.
- In the Banni grasslands, studies have found that the spread of the invasive species Prosopis juliflora — which the Gujarat Forest Department planted in 1961 to combat desertification and provide firewood to communities — has since transformed swaths of the grasslands into a Prosopis woodland.
- In the Shola grasslands, eucalyptus plantations have run amok, whereas the Malabar silk-cotton tree has been running riot in the wet Terai grasslands of the Himalaya.
Way forward
- To combat the increasing threat of woody encroachment on grasslands, we need long-term ecological monitoring in open ecosystems because it provides valuable fine-scale information. A lot more science is needed before actions and policy-changes.
- In India itself, we also need to dismantle colonial terminologies like “wastelands,” which perpetuate the misclassification of open ecosystems and passively promote activities that convert them to use for other purposes.
Editorial 2 : How does heat affect medicines and those taking them?
Context
The world just experienced the hottest day on record, and prolonged heat waves have become more common due to climate change and other conditions that can alter medications and their effects on patients taking them.
How does heat alter medicines?
- Medications for common conditions can increase patients’ sensitivity to heat by impairing the body’s response to high temperatures, including the ability to sweat and the rate of blood flow.
- When sweat evaporates, it removes heat from the skin. Not being able to sweat can cause the body to rapidly accumulate deadly levels of heat.
- Heat waves also increase the risk of deterioration for nearly all medications, whether capsules, sprays, tablets, syrups, or some other form, if they are not kept within a certain temperature range.
- The heat-related effects of medications can vary based on individual health status, dosage, and environmental conditions.
Drugs that increase sensitivity to heat
- Blood pressure and heart failure medications: Angiotensin converting enzyme (ACE) inhibitors suppress thirst, making it harder to know when to drink more water and increasing the risk of dehydration.
- Calcium channel blockers can cause mineral imbalances, making it harder for the body to regulate its temperature, while beta blockers can make it harder to sweat and keep the body cool.
- Diuretics, or water pills, can also cause dehydration and mineral imbalances.
- Allergy medications: Some over-the-counter antihistamines reduce sweating and can impair temperature regulation.
- Psychiatric medications: Certain antipsychotic medications limit ability to sweat.
- Some antidepressants have the opposite effect, increasing sweating and repressing thirst.
- Stimulants such as amphetamines and other drugs may interact with the central nervous system to raise body temperature.
- Thyroid medications: Thyroid hormone pills can also raise temperature, impair temperature regulation, and cause excessive sweating.
Safe temperature for storage
- Extreme heat (and extreme cold) can significantly alter the effectiveness of prescription and over-the-counter drugs.
- Some medications can tolerate temperatures up to 30 degrees C. However, in general, they should be stored at 15–77 degrees C in a cool, dry place, away from sunlight.
- Temperature storage guidelines for specific drugs can be found on manufacturers’ websites.
Conclusion
It’s hard to predict the extent to which a medication will degrade in extreme temperatures because each drug is different. However medicines should not be left in hot cars or for hours in hot mail boxes.