Ecosystem services provided by striped hyenas in the human-dominated landscape of Rajasthan, India.

In human-dominated landscapes, quantifying ecosystem services in terms of economic benefits could contribute to establishing peaceful coexistence between humans and large carnivores. In this study, we estimated the monetary value of scavenging benefits provided by striped hyenas (Hyaena hyaena) in an anthropogenic landscape in the semi-arid region of Rajasthan, India. We converted the value of domestic livestock carcasses consumed by striped hyenas from opportunity costs to quantify the value of this important ecosystem service to local people. We determined the monetary value of carcass disposals using two methods, including (1) electric cremation, and (2) pyre burning of animal carcasses. To determine the minimum number of striped hyenas, present in the study area, we employed a photo-capture approach, and we used scat analysis to determine the livestock consumed by striped hyenas. We estimated that striped hyenas removed 23.13 tons (4.4 %) of livestock carcass waste from the total of 525.68 tons of waste generated per year in the Intensive Study Area (ISA). The annual monetary value of livestock carcass waste removal by striped hyenas in the ISA was estimated to be ~US$ 7095 for electric cremation and US$ 49,665 for pyre burning. Our study demonstrates the economic benefit of scavenging services provided by striped hyenas in areas where anthropogenic food is abundant. In such areas, as hyenas scavenge anthropogenic food, local communities benefit from waste management. Using alternative carcass disposal methods without striped hyenas would be expensive and likely environmentally damaging.

High striped hyena density suggests coexistence with humans in an agricultural landscape, Rajasthan.

Understanding the mechanism of coexistence, where carnivores adapt to humans and vice versa in the shared landscape, is a key determinant of long-term carnivore conservation but is yet to be comprehensively examined. We explored the coexistence mechanism of striped hyena (Hyaena hyaena) and humans in the shared landscape of Sawai Mansingh Wildlife Sanctuary (SMS WLS), Rajasthan, from November 2019 to March 2021. We used data derived from motion sensors-based surveys, satellite remote sensing images, and household questionnaires to understand socio-ecological, environmental and anthropogenic factors facilitating hyena persistence in the shared landscape. The high density (12 individuals/100 km2) striped hyena in the landscape revealed the coexistence with humans. Being scavengers, they get subsidised food sources and are perceived as low-risk species by humans. Striped hyena minimised temporal activity during the daytime when human activity peaked. However, the highest activity overlap was observed in the agricultural area (Δ1 = 0.39), and likely depicts the high activity due to agricultural practices. While the human settlement was positively associated with the detection of hyenas, the probability of striped hyena captures increased with decreasing distance from human settlement, possibly influenced by high carcass availability, providing the easiest food resources to striped hyena, and allowing them to coexist with humans. This study demonstrates the coexistence of hyenas and humans in the shared landscape supported by mutual benefits, where hyenas benefit from anthropogenic food from scavenging, while humans benefit from waste removal and the non-lethal nature hyenas.

Mechanism Underlying Heat Stability of the Rice Endosperm Cytosolic ADP-Glucose Pyrophosphorylase.

Rice grains accumulate starch as their major storage reserve whose biosynthesis is sensitive to heat. ADP-glucose pyrophosphorylase (AGPase) is among the starch biosynthetic enzymes severely affected by heat stress during seed maturation. To increase the heat tolerance of the rice enzyme, we engineered two dominant AGPase subunits expressed in developing endosperm, the large (L2) and small (S2b) subunits of the cytosol-specific AGPase. Bacterial expression of the rice S2b with the rice L2, potato tuber LS (pLS), or with the mosaic rice-potato large subunits, L2-pLS and pLS-L2, produced heat-sensitive recombinant enzymes, which retained less than 10% of their enzyme activities after 5 min incubation at 55°C. However, assembly of the rice L2 with the potato tuber SS (pSS) showed significantly increased heat stability comparable to the heat-stable potato pLS/pSS. The S2b assembled with the mosaic L2-pLS subunit showed 3-fold higher sensitivity to 3-PGA than L2/S2b, whereas the counterpart mosaic pLS-L2/S2b showed 225-fold lower sensitivity. Introduction of a QTC motif into S2b created an N-terminal disulfide linkage that was cleaved by dithiothreitol reduction. The QTC enzyme showed moderate heat stability but was not as stable as the potato AGPase. While the QTC AGPase exhibited approximately fourfold increase in 3-PGA sensitivity, its substrate affinities were largely unchanged. Random mutagenesis of S2bQTC produced six mutant lines with elevated production of glycogen in bacteria. All six lines contained a L379F substitution, which conferred enhanced glycogen production in bacteria and increased heat stability. Modeled structure of this mutant enzyme revealed that this highly conserved leucine residue is located in the enzyme's regulatory pocket that provides interaction sites for activators and inhibitors. Our molecular dynamic simulation analysis suggests that introduction of the QTC motif and the L379F mutation improves enzyme heat stability by stabilizing their backbone structures possibly due to the increased number of H-bonds between the small subunits and increased intermolecular interactions between the two SSs and two LSs at elevated temperature.