The distribution and drivers of tree cover in savannas and forests across India

The distribution of forest and savanna biomes and the role of resources (climate and soil) and disturbances (fire and herbivory) in determining tree-grass dynamics remains elusive and variable across geographies. This is especially problematic in Indian savannas which have been historically misclassified as degraded forests and are targeted for tree-planting. Here, we examine biome distribution and determinants through the lens of tree cover across India. Our analyses reveal four distinct zones of differing tree cover, with intermediate zones containing savanna vegetation. Rainfall seasonality determines maximum possible tree cover non-linearly. Once rainfall seasonality is factored out, soil sand fraction and topography partially explain residual variation of tree cover. High domestic livestock herbivory and other anthropogenic pressures reduce tree cover. Lastly, lack of detectable fires precludes robust conclusions about the relationship between fire and tree cover. By considering these environmental drivers in restoration planning, we can improve upon simplistic tree planting initiatives that may be detrimental to Indian savannas

Natural climate solutions

Our thanks for inputs by L. Almond, A. Baccini, A. Bowman, S. CookPatton, J. Evans, K. Holl, R. Lalasz, A. Nassikas, M. Spalding, M. Wolosin, and expert elicitation respondents. Our thanks for datasets developed by the Hansen lab and the NESCent grasslands working group (C. Lehmann, D. Griffith, T. M. Anderson, D. J. Beerling, W. Bond, E. Denton, E. Edwards, E. Forrestel, D. Fox, W. Hoffmann, R. Hyde, T. Kluyver, L. Mucina, B. Passey, S. Pau, J. Ratnam, N. Salamin, B. Santini, K. Simpson, M. Smith, B. Spriggs, C. Still, C. Strömberg, and C. P. Osborne). This study was made possible by funding from the Doris Duke Charitable Foundation. Woodbury was supported in part by USDA-NIFA Project 2011-67003-30205 Data deposition: A global spatial dataset of reforestation opportunities has been deposited on Zenodo (https://zenodo.org/record/883444). This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1710465114/-/DCSupplemental.Peer reviewedPublisher PD

Natural climate solutions for the United States

© The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Science Advances 4 (2018): eaat1869, doi:10.1126/sciadv.aat1869.Limiting climate warming to <2°C requires increased mitigation efforts, including land stewardship, whose potential in the United States is poorly understood. We quantified the potential of natural climate solutions (NCS)—21 conservation, restoration, and improved land management interventions on natural and agricultural lands—to increase carbon storage and avoid greenhouse gas emissions in the United States. We found a maximum potential of 1.2 (0.9 to 1.6) Pg CO2e year−1, the equivalent of 21% of current net annual emissions of the United States. At current carbon market prices (USD 10 per Mg CO2e), 299 Tg CO2e year−1 could be achieved. NCS would also provide air and water filtration, flood control, soil health, wildlife habitat, and climate resilience benefits.This study was made possible by funding from the Doris Duke Charitable Foundation. C.A.W. and H.G. acknowledge financial support from NASA’s Carbon Monitoring System program (NNH14ZDA001N-CMS) under award NNX14AR39G. S.D.B. acknowledges support from the DOE’s Office of Biological and Environmental Research Program under the award DE-SC0014416. J.W.F. acknowledges financial support from the Florida Coastal Everglades Long-Term Ecological Research program under National Science Foundation grant no. DEB-1237517

Protecting 30% of the planet for nature: costs, benefits and economic implications

A. Waldron, K. Nakamura, J. Sze, T. Vilela, A. Escobedo, P. Negret Torres, R. Button, K. Swinnerton, A. Toledo, P. Madgwick, N. Mukherjee were supported by National Geographic and the Resources Legacy Fund. V. Christensen was supported by NSERC Discovery Grant RGPIN-2019-04901. M. Coll and J. Steenbeek were supported by EU Horizon 2020 research and innovation programme under grant agreement No 817578 (TRIATLAS). D. Leclere was supported by TradeHub UKRI CGRF project. R. Heneghan was supported by Spanish Ministry of Science, Innovation and Universities, Acciones de Programacion Conjunta Internacional (PCIN-2017-115). M. di Marco was supported by MIUR Rita Levi Montalcini programme. A. Fernandez-Llamazares was supported by Academy of Finland (grant nr. 31176). S. Fujimori and T. Hawegawa were supported by The Environment Research and Technology Development Fund (2-2002) of the Environmental Restoration and Conservation Agency of Japan and the Sumitomo Foundation. V. Heikinheimo was supported by Kone Foundation, Social Media for Conservation project. K. Scherrer was supported by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme under grant agreement No 682602. U. Rashid Sumaila acknowledges the OceanCanada Partnership, which funded by the Social Sciences and Humanities Research Council of Canada (SSHRC). T. Toivonen was supported by Osk. Huttunen Foundation & Clare Hall college, Cambridge. W. Wu was supported by The Environment Research and Technology Development Fund (2-2002) of the Environmental Restoration and Conservation Agency of Japan. Z. Yuchen was supported by a Ministry of Education of Singapore Research Scholarship Block (RSB) Research Fellowship

Working paper analysing the economic implications of the proposed 30% target for areal protection in the draft post-2020 Global Biodiversity Framewor

58 pages, 5 figures, 3 tables- The World Economic Forum now ranks biodiversity loss as a top-five risk to the global economy, and the draft post-2020 Global Biodiversity Framework proposes an expansion of conservation areas to 30% of the earth’s surface by 2030 (hereafter the “30% target”), using protected areas (PAs) and other effective area-based conservation measures (OECMs). - Two immediate concerns are how much a 30% target might cost and whether it will cause economic losses to the agriculture, forestry and fisheries sectors. - Conservation areas also generate economic benefits (e.g. revenue from nature tourism and ecosystem services), making PAs/Nature an economic sector in their own right. - If some economic sectors benefit but others experience a loss, high-level policy makers need to know the net impact on the wider economy, as well as on individual sectors. [...]A. Waldron, K. Nakamura, J. Sze, T. Vilela, A. Escobedo, P. Negret Torres, R. Button, K. Swinnerton, A. Toledo, P. Madgwick, N. Mukherjee were supported by National Geographic and the Resources Legacy Fund. V. Christensen was supported by NSERC Discovery Grant RGPIN-2019-04901. M. Coll and J. Steenbeek were supported by EU Horizon 2020 research and innovation programme under grant agreement No 817578 (TRIATLAS). D. Leclere was supported by TradeHub UKRI CGRF project. R. Heneghan was supported by Spanish Ministry of Science, Innovation and Universities, Acciones de Programacion Conjunta Internacional (PCIN-2017-115). M. di Marco was supported by MIUR Rita Levi Montalcini programme. A. Fernandez-Llamazares was supported by Academy of Finland (grant nr. 311176). S. Fujimori and T. Hawegawa were supported by The Environment Research and Technology Development Fund (2-2002) of the Environmental Restoration and Conservation Agency of Japan and the Sumitomo Foundation. V. Heikinheimo was supported by Kone Foundation, Social Media for Conservation project. K. Scherrer was supported by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme under grant agreement No 682602. U. Rashid Sumaila acknowledges the OceanCanada Partnership, which funded by the Social Sciences and Humanities Research Council of Canada (SSHRC). T. Toivonen was supported by Osk. Huttunen Foundation & Clare Hall college, Cambridge. W. Wu was supported by The Environment Research and Technology Development Fund (2-2002) of the Environmental Restoration and Conservation Agency of Japan. Z. Yuchen was supported by a Ministry of Education of Singapore Research Scholarship Block (RSB) Research FellowshipPeer reviewe

Forest restoration in India: opportunities and realities

There is an unprecedented urgency in mitigating the impacts of climate change and forest restoration is at the forefront. Global and national policy fora have championed the cause of forest restoration as a natural climate solution, culminating in the current UN Decade of Ecosystem Restoration. It has often been touted as a cost-effective and scalable panacea with the potential to deliver a variety of benefits beyond sequestration of carbon. However, the reality of this strategy is more complex, warranting careful scientific assessment targeted at informing effective policy and practice. In this thesis, I evaluate the opportunities and realities of forest restoration in India by undertaking three interlinked pieces of research. In Chapter 3, I estimate where there is opportunity area for forest restoration and the resulting climate change mitigation potential in each of the 28 Indian states. A novel methodological approach, using India-specific data when possible, included field-collected points of different forest types, machine learning, spatial analyses, and national inventory data of carbon pools for different forest canopy densities. I find there is just 1.58 million hectares (Mha) opportunity area resulting in 61.3 TgC mitigation potential, with immense variation between states. Approximately half of this opportunity is in degraded, barren and scrub land. Having accounted for fine-scale variation in India’s complex patterns of existing land uses and covers, these estimates are lower than India-specific estimates from global studies, suggesting that the potential of forest restoration to mitigate climate change in India has been overestimated. However, I estimate there is 14.67 Mha opportunity area for agroforestry, providing 98.1 TgC climate change mitigation potential at the pan- India scale, reflecting the importance of context-appropriate strategies such as agroforestry in countries with large smallholder agricultural footprints. Overall, the potential of forest restoration and agroforestry in India contributes minimally to India’s pledge to the Paris Agreement 2015, underscoring the need for a diversified portfolio of climate change mitigation strategies. Chapter 4 assesses the patterns of tree cover across India’s savanna and forest biomes and its determinants. India’s savanna biome is often forgotten and misunderstood considering its relationship to colonial land management practises and India’s quest to meet its ambitious international climate pledges. Combining remotely sensed information about tree cover and climate with empirical evidence of endemic savanna plants, I revealed four distinct climatic zones of tree cover, with a clear ‘no go’ zone for afforestation. I then applied additional remotely sensed information about soil, fire and domestic livestock herbivory pressure to reach novel insights about the determinants of tree cover. Topography is a key regulator of tree cover, with anthropogenic activities and high herbivory pressure also limiting tree cover from reaching its maximum climatic potential. In contrast to evidence from South America, Africa and Australia, there is no clear evidence of the effect of fire disturbances on tree cover, potentially highlighting the different extent and intensities of fire regimes and historic and contemporary views on fire suppression, across South Asia. These new insights from South Asia help to fill a missing piece in the global puzzle of biome distribution. They also show the need to account for climatic, topographic and disturbance factors when planning forest restoration, moving beyond simplistic tree-planting initiatives. Chapter 5 uses spatial prioritization methods to assess trade-offs in key environmental and social outcomes from single- and multi-objective forest restoration strategies. I focus on three outcomes- climate change mitigation, habitat creation for forest-dependent mammals and societal provision for human basic needs of energy, livelihoods, and housing construction material from naturally regenerating native forests across India. I find that multi-objective forest restoration strategies have the least trade-offs between the above environmental and societal outcomes and achieve most of the benefits of all single-objective strategies. The benefits from a multi-objective strategy were geographically distributed across India implying flexibility and options for on-the-ground implementation. Lastly, strategies focused on societal benefit or combined outcomes have the potential to deliver human basic needs to the highest fraction of socioeconomically disadvantaged people compared to forest restoration strategies aimed at climate change mitigation or biodiversity. Overall, the thesis highlights the crucial need to consider contextual factors when planning forest restoration in India, including existing land uses and covers, distribution of human population density, natural disturbance regimes and priority areas delivering a variety of outcomes. Hence, the findings in this thesis have wider implications for other countries in the tropical biome. The novelty of this work includes (i) estimation of opportunity area and resulting climate change mitigation potential of forest restoration at the sub-jurisdiction spatial scale, crucial for informing policy and decision making; (ii) estimation of the immense potential of agroforestry as a strategic climate change mitigation action; (iii) determination of fresh insights about the factors that drive tree cover across forest and savannas; and (iv) assessment of the potential of multi-objective forest restoration strategies to deliver multiple environment and societal outcomes, for a future in which humans and nature thrive

Constituents and drivers of composition, diversity and structure of a Congolese forest

Tropical forest systems occupy 2% of the earth’s land surface but host nearly 50% of the world’s forests and support unique flora and fauna and ecological processes. They also provide a multitude of ecosystem services ranging from the provision of food and water to supporting livelihoods and climate change mitigation. However, tropical forests are under immense anthropogenic pressures, including conversion of forestland for agricultural purposes, logging and extraction of timber, and exploitation via hunting and poaching. These pressures fragment forests and alter ecological processes that are linked to the many ecosystem services they provide. The Congolese forest of Central Africa is an important tropical forest belt of the world with a unique history of anthropogenic pressures, particularly logging and hunting activities. In this study, I examine the forests of the northern Republic of the Congo to understand the role of logging and hunting on forest diversity, composition, and structure. Specifically, I identify forest tree communities and determine the extent to which environmental drivers versus anthropogenic disturbance dictate forest composition, diversity and structure. To do so, I use a range of statistical techniques, including non-metric multidimensional scaling, classification and multi-level pattern analysis and multiple regression approaches. The results of my study reveal that variation in species composition is explained by disturbance type (combination of logging and hunting, logging only, and no disturbance), distance to Kabo village (proxy for disturbance), and logging. I determined five tree species groups across the study area that largely represents a gradient of disturbance. Areas having combined pressures of hunting and selective logging included the highest number of species groups, while pristine areas included the lowest number of species groups. In addition, the indicator tree species characterizing the species groups also reflected the level of disturbance, with highly disturbed plots containing more characteristic secondary tree species and pristine areas containing primary tree species. For drivers of tree species diversity, I concluded that edaphic factors including pH and phosphorous explain variation in diversity. Lastly, I determined there to be no significant driver of basal area across the plots, but variation in wood density was driven by total nitrogen and soil texture. My study highlights the effects of disturbance on species composition across this forested landscape; whereas soil characteristics seemed to have a stronger role in controlling forest diversity and structure, although additional research is needed to fully elucidate the observed results. More studies are needed to decouple the effects of anthropogenic pressures and environmental factors on forest composition, diversity and structure, thereby providing more insight about these forests

Determining levels of cryptic diversity within the endemic frog genera, Indirana and Walkerana, of the Western Ghats, India.

A large number of species in the tropics are awaiting discovery, many due to their cryptic morphology ie. lack of discernable morphological difference. We explored the presence of cryptic lineages within the frog genera, Indirana and Walkerana, which are endemic to the Western Ghats of Peninsular India. By reconstructing a phylogeny using 5 genes and robust geographic sampling, we delimited 19 lineages along a population-species continuum, using multiple criteria including haplotype clusters, genetic distance, morphological distinctness, and geographical separation. Of these 19 lineages, 14 belonged to the genus Indirana and 5 to the genus Walkerana. Divergence dating analyses revealed that the clade comprising Indirana and Walkerana began diversifying around 71 mya and the most recent common ancestor of Indirana and Walkerana split around 43 mya. We tested for the presence of cryptic lineages by examining the relationship between genetic and morphological divergence among related pairs within a pool of 15 lineages. The pairs showed strong morphological conservatism across varying levels of genetic divergence. Our results highlight the prevalence of morphologically cryptic lineages in these ancient endemic clades of the Western Ghats. This emphasizes the significance of other axes, such as geography, in species delimitation. With increasing threats to amphibian habitats, it is imperative that cryptic lineages are identified so that appropriate conservation measures can be implemented

Knowledge diffusion within a large conservation organization and beyond

<div><p>The spread and uptake of new ideas (diffusion of innovations) is critical for organizations to adapt over time, but there is little evidence of how this happens within organizations and to their broader community. To address this, we analyzed how individuals accessed information about a recent science innovation at a large, international, biodiversity conservation non-profit–The Nature Conservancy–and then traced the flow of how this information was shared within the organization and externally, drawing on an exceptionally data-rich environment. We used surveys and tracking of individual internet activity to understand mechanisms for early-stage diffusion (knowledge seeking and sharing) following the integration of social science and evidence principles into the institutional planning framework: Conservation by Design (CbD 2.0). Communications sent to all employees effectively catalyzed 56.4% to exhibit knowledge seeking behavior, measured by individual downloads from and visits to a restricted-access site. Individuals who self-reported through a survey that they shared information about CbD 2.0 internally were more likely to have both received and sought out information about the framework. Such individuals tended to hold positions within a higher job grade, were more likely to train others on CbD as part of their job, and to enroll in other online professional development offerings. Communication strategies targeting external audiences did not appear to influence information seeking behavior. Staff who engaged in internal knowledge sharing and adopting “evidence” practices from CbD 2.0 were more likely to have shared the document externally. We found a negative correlation with external sharing behavior and in-person trainings. Our findings suggest repeated, direct email communications aimed at wide audiences can effectively promote diffusion of new ideas. We also found a wide range of employee characteristics and circumstances to be associated with knowledge diffusion behavior (at both an organizational and individual level).</p></div