Assessing the vulnerability of socio-environmental systems to climate change along an altitude gradient in the Indian Himalayas

Landsat-8 and Sentinel-2 based Forest fire burn area mapping using machine learning algorithms on GEE cloud platform over Uttarakhand, Western Himalaya

Biodiversity faces many threats and these can interact to produce outcomes that may not be predicted by considering their effects in isolation. Habitat loss and fragmentation (hereafter 'fragmentation') and altered fire regimes are important threats to biodiversity, but their interactions have not been systematically evaluated across the globe. In this comprehensive synthesis, including 162 papers which provided 274 cases, we offer a framework for understanding how fire interacts with fragmentation. Fire and fragmentation interact in three main ways: (i) fire influences fragmentation (59% of 274 cases), where fire either destroys and fragments habitat or creates and connects habitat; (ii) fragmentation influences fire (25% of cases) where, after habitat is reduced in area and fragmented, fire in the landscape is subsequently altered because people suppress or ignite fires, or there is increased edge flammability or increased obstruction to fire spread; and (iii) where the two do not influence each other, but fire interacts with fragmentation to affect responses like species richness, abundance and extinction risk (16% of cases). Where fire and fragmentation do influence each other, feedback loops are possible that can lead to ecosystem conversion (e.g. forest to grassland). This is a well-documented threat in the tropics but with potential also to be important elsewhere. Fire interacts with fragmentation through scale-specific mechanisms: fire creates edges and drives edge effects; fire alters patch quality; and fire alters landscape-scale connectivity. We found only 12 cases in which studies reported the four essential strata for testing a full interaction, which were fragmented and unfragmented landscapes that both span contrasting fire histories, such as recently burnt and long unburnt vegetation. Simulation and empirical studies show that fire and fragmentation can interact synergistically, multiplicatively, antagonistically or additively. These cases highlight a key reason why understanding interactions is so important: when fire and fragmentation act together they can cause local extinctions, even when their separate effects are neutral. Whether fire-fragmentation interactions benefit or disadvantage species is often determined by the species' preferred successional stage. Adding fire to landscapes generally benefits early-successional plant and animal species, whereas it is detrimental to late-successional species. However, when fire interacts with fragmentation, the direction of effect of fire on a species could be reversed from the effect expected by successional preferences. Adding fire to fragmented landscapes can be detrimental for species that would normally co-exist with fire, because species may no longer be able to disperse to their preferred successional stage. Further, animals may be attracted to particular successional stages leading to unexpected responses to fragmentation, such as higher abundance in more isolated unburnt patches. Growing human populations and increasing resource consumption suggest that fragmentation trends will worsen over coming years. Combined with increasing alteration of fire regimes due to climate change and human-caused ignitions, interactions of fire with fragmentation are likely to become more common. Our new framework paves the way for developing a better understanding of how fire interacts with fragmentation, and for conserving biodiversity in the face of these emerging challenges.

How fire interacts with habitat loss and fragmentation.

The current study focuses on the impacts of projected climate change scenarios and land change dynamics on the suitable habitat of some dominant Oak species (Quercus leucotrichophora, Quercus semecarpifolia, and Quercus floribunda) in western Himalaya. Two IPCC AR5 climate change scenarios viz. RCP 4.5 and RCP 8.5 from a suite of Global Climate Models best suited for Himalaya were used to model the changes in the suitable bioclimatic envelop of these Oak species in the western Himalayas for their probability current distributions and potential future distributions (2070) with the help of ensemble modelling in R platform. The formations of projected distribution areas for these species under climate change exhibits a north-eastward shift and a significant decrease in their climatic niche under projected climate change across both RCP’s, with RCP 4.5 showing increased loss of climatic niche (fundamental niche) of Oak species compared to RCP 8.5. The study also captures the footprints of current and projected land use land cover dynamics on the current and future distribution ranges of each Oak species in Western Himalaya which is observed to adversely affect the Oak forests by further reducing the extent of their realised niche.

Assessing the vulnerability of Oak (Quercus) forest ecosystems under projected climate and land use land cover changes in Western Himalaya

Estimates of reactive trace gases (NMVOCs, CO and NOx) and their ozone forming potentials during forest fire over Southern Himalayan region

Forest fire is one of the major causes of degradation in western Himalaya, and is an annual phenomenon in more than 50% in the forests of Uttarakhand state. Fire danger models are useful for the fi...

P. Ramachandra Prasad

Papers

Forest fire risk modeling in Uttarakhand Himalaya using TERRA satellite datasets