Many ecosystems exhibit striking patterns in the spatial distribution of organisms, for example, patterns of clumping and dispersion in semi-arid vegetation, mussel in inter-tidal beds and even sea-grass and macroalgae. Elucidating local-scale processes that generate these macroscopic patterns is of fundamental ecological importance. In addition, these patterns may provide insights and tools to quantify stability and forecast the future dynamics of ecosystems. We now know that several ecosystems may undergo abrupt and irreversible changes in the density of their dominant communities, potentially resulting in local extinctions. Discerning the vulnerability of ecosystems to such regime shifts has become an important focal area of research in recent times. In this thesis, I investigate methods to detect vulnerability of ecosystems using high-resolution spatial data, which is becoming increasingly cheap and easily available. To do this, I use spatially explicit models of ecosystem regime shifts, inspired by simple models of state transitions in the physics literature. I also demonstrate the theoretical results with vegetation data from semi-arid ecosystems. My main findings are that some key previously proposed metrics of regime shifts when applied to high-resolution spatial data can give misleading signals and are theoretically unfounded. I argue that a clear understanding of how local interactions between organisms scale to their spatial distribution is crucial to correctly inferring ecosystem stability.

Research on intrasexual competition has largely focused on males. Competitive signalling and aggression strategies used by males have been widely studied. It is increasingly recognised that intrasexual competition may be common among females too; but our understanding about female competitive strategies is largely restricted to eusocial insects and cooperative breeding societies. Unlike males who compete to mate, females in polygynous systems rarely get large immediate fitness gains through intrasexual competition, since they are limited by the time it takes to successfully produce offspring. Additionally, because of their investment in young, the costs of overt competition, such as conspicuous signalling and physical aggression, are expected to be relatively high for females. Accordingly, females are expected to use inconspicuous broadcast displays, should be more sensitive to the perceived threat and invest in competitive signalling and aggression only when the threat of a competitor is high. We tested these hypotheses by observing P. dorsalis individuals in the wild and simulating intruder threat at multiple threat levels on their territories. Analysis revealed that females use relatively less conspicuous behaviours as broadcast displays. While both sexes increase signalling in high threat conditions as compared to low threat conditions, females show a substantially larger increase than males. Sex differences in physical aggression were also seen. Here, I discuss the implications of these sex differences in signalling and aggression in intrasexual competition in a polygynous tropical agamid.

How biodiversity is generated and maintained is a fundamental question in ecology and evolutionary biology, and studying diversification can give us key insights into this process. In my thesis, I carried out species delimitation and investigated the pattern of lineage and morphological diversification in a continental radiation of Hemidactylus geckos. The underlying role of climate in generating these patterns was also examined. Through systematic sampling and molecular phylogenetic work, evolutionary history of these geckos was traced. Fossil-calibrated phylogeny showed that Hemidactylus started diversifying ~36Mya, with an early-burst in lineage diversification. Using a hypothesis testing framework, I show that the drying caused during the Eocene-Oligocene cooling could have provided ecological opportunity driving lineage diversification. I then examined ecological diversification by studying morphological evolution. Species of Hemidactylus are found in various microhabitats and the relationship between habitat specialists and their morphology was assessed. We found significant differences in morphology between terrestrial and climbing species. Unlike lineage diversification, morphological diversification showed a delayed increase in disparity. Ancestral state reconstruction of terrestrial and climbing forms showed that the terrestrial geckos have evolved at least five times independently across the phylogeny. The shift from climbing to terrestrial state began after 15Mya, concurrent with aridification in Peninsular India that led to the establishment of open habitats. Thus, this study highlights the role of two disparate climatic events governing the asynchronous lineage and morphological diversification in this adaptive radiation.

In an age where the phrase “climate change” can no longer be ignored, we (scientists) are expected to know if and how global warming will change the world we live in. There are so many papers that predict dramatic ecological changes based on organismal responses to climatic projections; and much of those prediction are about species extinctions and range shifts. A closer look at some of these papers quickly reveal that we have forgotten our basics: the physics and physiology of thermal adaptation. I will take us quickly through a lesson in thermal biology of ectotherms and then together, we can critically look at some of the global analyses of predicted lizard extinctions (that are simply rubbish).

South Africa lies at the meeting point of two ocean systems and experiences significant clines in environmental parameters such as temperature and productivity, which in turn affect the composition and species diversity along its coastline. As such, several biogeographic regions are recognised, which differ in faunal and floral composition. My talk examines the genetic, and more recently, genomic advances that try to unravel the processes that have shaped the patterns of species diversity, particularly in South Africa, with particular emphasis on the past fifteen years. My talk provides an overview of the natural history of South Africa, its marine biogeography and the challenges, constraints and successes of our lab in sequencing species at different spatio-temporal scales and contributing towards highlighting South Africa not only as a region of exception natural interest, but also scientific excellence.

Agricultural intensification is regarded as a potential solution to the rising demand for food while limiting further loss of habitat. However, agricultural lands can be rich in biodiversity and changes to way those lands are managed have the potential to drive substantial biodiversity loss. We therefore have an imperative to understand how species use landscape elements in farmlands to help develop strategies that can minimize losses in the face of intensification. In this seminar I will present case studies showing how spatial and temporal variation in the farming matrix influences reptile and frog communities and individual species. Which taxon is most at risk? How are they influenced by crop harvesting? How is their capacity to orient towards habitat altered by changes in agricultural practices? What is the risk of predation across landscape elements? Answers to these questions provide new insight into the complex responses of wildlife to changes in farming landscapes, but also provide some guidance for conservation planning as we move forwards towards peak-human.

Agricultural intensification is regarded as a potential solution to the rising demand for food while limiting further loss of habitat. However, agricultural lands can be rich in biodiversity and changes to way those lands are managed have the potential to drive substantial biodiversity loss. We therefore have an imperative to understand how species use landscape elements in farmlands to help develop strategies that can minimize losses in the face of intensification. In this seminar I will present case studies showing how spatial and temporal variation in the farming matrix influences reptile and frog communities and individual species. Which taxon is most at risk? How are they influenced by crop harvesting? How is their capacity to orient towards habitat altered by changes in agricultural practices? What is the risk of predation across landscape elements? Answers to these questions provide new insight into the complex responses of wildlife to changes in farming landscapes, but also provide some guidance for conservation planning as we move forwards towards peak-human.

Anand Malligavad is the head Projects and CSR of Sansera Foundation. He spearheaded the CSR initiative by his company to restore Kyalasanahalli lake in Anekal Taluk outside Bangalore. When the company
started this initiative in early 2017, there was hardly any water in the lake, and the lake suffered from encroachment and dumping of construction materials. We will first screen a short movie that describes
how Anand and his team worked with the villages around the lake to reclaim land from encroachment, desilt the lake and increase its water holding capacity by 27 times. With heavy monsoons last year, the lake
is now fully restored. Partnering with the NGO SayTrees, 6000 saplings were planted by volunteers on World Environment Day last year, including a large Miyawaki forest where local species of trees are
planted in high density. The lake environment is now attracting many species of birds, fish and insects and may serve as an interesting venue for ecological research. Anand will describe how the success of
this project has inspired other companies to take up restoration of other lakes in Anekal taluk-- the goal being to rejuvenate all the interconnected lakes in that area. He will briefly talk about other CSR
projects of his company in that area, including working with 22 government schools to improve the quality of education, and involve children in planting Miyawaki forests in their school compounds. Anand will
also provide pointers on approaching companies for CSR funding for environmentally or socially relevant projects.

Connectivity is considered to be essential in enhancing biodiversity conservation efforts and for benefiting adjacent areas. In the marine environment, connectivity among populations arises from dispersal during the larval stage for most sedentary species and particularly among sessile benthic invertebrates. Offspring released into the water column are transported and dispersed almost passively by water flow due to limited larval motility as compared to the horizontal flow speed. As a consequence, the spatio-temporal variability of hydrodynamics primarily shapes larval transport, which is the integration of larval dispersal over the pelagic larval duration of a species. Ocean modelling works well for hindcasting realistic coastal circulation, and can provide a comprehensive description of flow variability at high spatial and temporal resolutions, which improves the description of larval transport. In this talk, I will examine how larval transport estimates derived from bio-physical modelling can be useful to marine biodiversity conservation through the design of Marine Protected Areas (MPAs), by taking examples from the Mediterranean Sea. Species persistence in both isolated MPAs and in a network of MPAs will be discussed.

Wings in insects come in many forms. I will show how coloration and wings in insect wings are shaped by different and conflicting selection pressures. I will do this by presenting results and conclusions from several studies. 1) By estimating damselfly wing reflectance, and use receptor noise models we have explored the visual discriminability of wing coloration in a three level system: bird, damselfly and fly. Results show that males are more discriminable. 2) I will also show how bird predation selects for wing shape and wing coloration in a damselfly system. 3) By using a phylogenetic approach we have shown that wing shape and wing coloration are associated. Our results show interesting differences in wing shape among species that probably are shaped by sexual selection. 4) Finally, I will present results from a study exploring how range size and migration affects wing shape in North American dragonflies.