Restoration in the Western Himalaya: a systematic review of current efforts and implications for the future

Abstract

The Western Himalaya faces significant ecological challenges, including deforestation, biodiversity loss, and unsustainable development, prompting extensive restoration efforts. These scattered restoration practices, ranging from large-scale afforestation to more nuanced restoration strategies, remain under-assessed. Therefore, we undertook a systematic review following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, identifying dominant research themes and various trends in restoration practices to detect knowledge gaps and propose future priorities. We analyzed 100 peer-reviewed and gray literature articles from January 1990 to February 2024. Most interventions were reported from Uttarakhand (53.7%, n = 183), followed by Himachal Pradesh (27.9%), Ladakh (10.3%), and Jammu and Kashmir (8.2%). Afforestation was the dominant practice (34.3%, n = 117), concentrated in Himachal Pradesh and Ladakh, while forest restoration (17.6%, n = 60) was concentrated in Uttarakhand (n = 56). Research themes centered on “Restoration Techniques” (37.5%) and “Stakeholder Engagement” (22.7%), while “Policy & Governance” and “Climate Change Mitigation & Adaptation” were under-represented. Restoration goals primarily targeted “Ecosystem Functioning & Services” (32%) and “Biodiversity Enhancement” (22%) but largely ignored “Disaster Resilience” and “Water Management.” Nearly half of the species planted were non-native (47.6%), with a median of four species per site, and monitoring practices were inconsistently reported, raising concerns about long-term outcomes. Natural regeneration was notably understudied, while tokenistic tree-planting drives were rampant, particularly in the Trans-Himalayas. We suggest that research on restoration ecology and its application to Western Himalayan ecosystems should be prioritized, together with collaboration with practitioners and adoption of consistent monitoring to address the landscape's unique challenges.