The Roles of Time and Disturbance Regimes in Savanna Plant Communities

Despite growing recognition that Earth’s biodiverse grasslands and savannas require long periods of time to accumulate their diversity, the idea that grasslands can be as ancient as forests (i.e., the old-growth grassland concept) is still not widely accepted. Consequently, biodiversity of tropical grasslands and savannas receives far less attention than tropical forests in studies of land-use change and environmental gradients. My dissertation addresses the ways that savanna plant diversity is shaped over long periods of time by fire and herbivores and over short periods of time by land-use change at the global, community, and organismal levels. In my first chapter, as a global test of the old-growth grassland concept, I performed a meta-analysis to compare plant species richness of old-growth grasslands and secondary grasslands (i.e., grasslands recovering after destruction by agriculture and afforestation). I found that old-growth grasslands had 37% more species compared to secondary grasslands, and that secondary grasslands need at least a century to recover their former richness. This analysis highlighted the paucity of studies on land-use change in tropical savannas, and so for my second chapter, I quantified the effects of land use on savanna plant communities in India. I sampled four land uses (old-growth savanna, tillage agriculture, fallows, and tree plantations) stratified across a 1500 mm precipitation gradient. I found that tillage agriculture and tree planting have consistent negative effects on old-growth savanna plant diversity across the precipitation gradient. These findings underscore an urgent need to recognize expanding agriculture and afforestation as existential threats to fire- and grazer-maintained tropical savanna biodiversity. In my third chapter, I studied how fire and grazing have shaped grass functional traits of 337 native Texas grasses. I found that fire and grazing have resulted in Texas grasses evolving strategies to either promote fire or promote grazing. Results highlight the legacy of Pleistocene megafauna and the undeniable role of fire in shaping the grass flora of Texas. In conclusion, my dissertation provides evidence to recognize fire and grazing as ancient forces shaping savanna biodiversity. Maintenance of these endogenous disturbance regimes in old-growth savannas and limiting land-use change should be a conservation priority

Data from: Seasonally dependent relationship between insect herbivores and host plant density in Jatropha nana- a tropical perennial herb

The fact that plant spatial aggregation patterns shape insect herbivore communities in a variety of ways has resulted in a large body of literature on the subject. The landmark resource concentration hypothesis predicts that density of insect-herbivores per plant will increase as host plant density increases. I examined this prediction across temporal samplings using Jatropha nana and the associated specialist insect-herbivores as a system. Through 12 field samplings, I modelled the effect of host plant density on insect-herbivore loads. The initial samplings (2-3) provided evidence for the resource concentration hypothesis with insect loads increasing with increasing host plant density, whereas the later samplings (4-5, 7-11) showed the opposite- a resource dilution pattern with decline of insect loads with increasing host plant density. These patterns also depend on the biology of the herbivores and have important implications on J. nana population dynamics

data for Dryad Nerlekar 2018 RCH paper

Sheet 1 contains the predictor and response variables re-arranged and results for Poisson regression analysis. Sheet 2 contains raw data for ramet density, insect load and relative abundance of each species over samplings

Occurrence of Trissolcus jatrophae Rajmohana et al. 2011 (Hymenoptera: Scelionidae) in Pune City, India

Trissolcus jatrophae Rajmohana et al. 2011, a parasitoid wasp has been observed to parasitize hemipteran eggs laid on Jatropha nana Dalzell &amp; Gibson (Euphorbiaceae) growing in Pune city, Maharashtra. In the present communication, this wasp has been reported for the first time on a new host plant species, and the occurrence of this wasp also forms a new distributional record.  </div

Flora of Fergusson College campus, Pune, India: monitoring changes over half a century

The present study was aimed at determining the vascular plant species richness of an urban green-space- the Fergusson College campus, Pune and comparing it with the results of the past flora which was documented in 1958 by Dr. V.D. Vartak. For this, the species richness data was obtained by both secondary sources and intensive surveys from 2009–2014. The data from the primary and secondary sources resulted in the documentation of 812 species belonging to 542 genera under 124 families, of which 534 species (65.8%) exists  today as compared to 654 in 1958 (net loss of 120 species). Of the 812 species listed, 278 species were observed only during the past, 210 species were exclusively recorded in the current survey and 324 species were observed both, in the past as well as current survey. Arboreal species richness recorded till date (196) in the campus accounts for 40.7% of that of the entire Pune City. Leguminosae and Poaceae were the dominant dicotyledonous and monocotyledonous families respectively and an inventory of all the species recorded is provided. Although the botanical garden over the past years has lost 187 species, it still houses rare species such as Acacia greggii, which has been reported from Maharashtra for the first time. Considering the rapidly changing urban land use in the city, much attention should be paid towards the conservation of these green spaces, for which such studies provide baseline data. </div

Restoring India's Terrestrial Ecosystems: Needs, Challenges, and Policy Recommendations

&lt;p&gt;This document is&nbsp;a product&nbsp;of the preparatory phase project of the National Mission on Biodiversity and Human Well-Being which was catalysed and supported by the Office of the Principal Scientific Advisor to the Government of India. It is the outcome of a series of stakeholder consultation meetings on ecological restoration of terrestrial landscapes and climate change in India. The insights from these meetings have been used to develop this document which highlights the challenges and best-practices in the restoration of terrestrial ecosystems, can serve as a guide for successful restoration of landscapes across different biomes of the Indian subcontinent, and help achieve India&rsquo;s commitments to the Bonn Challenge and the goals set by India for biodiversity conservation, land restoration, climate mitigation and adaptation.&lt;/p&gt

Comment on “The global tree restoration potential”

International audienc

Comment on “The global tree restoration potential”

Bastin et al.’s estimate (Reports, 5 July 2019, p. 76) that tree planting for climate change mitigation could sequester 205 gigatonnes of carbon is approximately five times too large. Their analysis inflated soil organic carbon gains, failed to safeguard against warming from trees at high latitudes and elevations, and considered afforestation of savannas, grasslands, and shrublands to be restoration.Funding: Supported by the Texas A&M Sid Kyle Global Savanna Research Initiative (T.W.B.); Swiss National Science Foundation (20FI20_173691) (N.B.); Centre National pour la Recherche Scientifique CNRS PICS 2018-2020 (RESIGRASS) (E.B.); CNPq (Brazil, 303179/2016-3) (G.D.); CNPq (Brazil) (G.W.F.); CNPq (Brazil, 303988/2018-5) (A.F.); NASA award NNX17AK14G (F.F.); NSF award 1354943 (W.A.H.); Fundação de Amparo à Pesquisa do Estado de Minas Gerais (Brazil, 2016/13232-5) (S.L.S.); the Office of the Royal Society (IC170015) (C.E.R.L.); CNPq (Brazil, 310345/2018-9) (G.E.O.); the Spanish Government (FIROTIC, PGC2018-096569-B-I00) (J.G.P.); the National Research Foundation (ACCESS, 114695) (N.S.); CNPq (Brazil, 303568/2017-8) (F.A.O.S.); NSF awards 1342703 and 1926431 (C.J.S. and D.M.G.); NSF award EAR-1253713 (C.A.E.S.); Deutsche Forschungsgemeinschaft grant 5579 POEM (V.M.T.); and USDA-NIFA Sustainable Agricultural Systems Grant 12726253 (J.W.V.