Google Earth Engine
Agriculture is critical to feeding a growing global population and to supporting the majority of the global extreme poor. At the same time, it is highly vulnerable to increasing environmental stress, be it in the form of increasing temperatures or water scarcity, and a major source of pollution, ecological degradation, habitat loss and GHG emissions.
Around the world, a variety of approaches are being promoted to achieve a more ecologically sustainable agriculture, some of which emphasise modern technologies while others call for a return to more traditional forms of cultivation. Unfortunately, the debate between these different approaches often remains more ideological than evidence-based, and policy often remains disturbingly un-informed.
I will attempt to cover some of the big questions on the issue, and appeal for faculty and students to play a more active role in addressing the challenge through a rigorous multidisciplinary approach that combines the life sciences, the physical sciences and the social sciences, and is intensively field based. I will focus on the potential and specific practical opportunities for collaborations between Israeli and Indian academia, two countries suffering from various forms of environmental stress that together, I will argue, can offer a new model of applied, impactful research on the topic.
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 marine 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 my thesis, I investigate methods to detect the vulnerability of ecosystems using high-resolution spatial data, which is becoming increasingly easy to procure. 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 infer ecosystem stability.
The energy animals spend in a day can be a useful currency to link their daily ecology to their evolutionary history. Animals need to maintain energy
balance to survive, deriving their daily energy requirements either from the environment or their energy stores. Maintaining daily energy balance is especially
challenging for hummingbirds, which are at the small size extreme for endothermy and use an expensive foraging method—hovering—that drives their energy
expenditure up. Unlike many larger endotherms, hummingbirds do not rely on endogenous energy stores through the day, so they must forage frequently, causing
activity costs to dominate their energy budget. By modeling their daily energy budget, I found that activity is indeed the largest component of their energy
budget (relative to thermoregulation, nighttime energy expenditure and basal metabolism). These high activity levels, and high muscle function, rather than
factors more impacted by surface area (e.g. thermoregulation), not only drive an individual’s daily energy budget but they also appear to determine the
allometric scaling of daily energy expenditure in hummingbirds. I found, by assessing 17 species over eight of the nine hummingbird clades, that hummingbird
daily energy expenditure varies with body-mass (M) as daily energy expenditure = 2.04*M0.95. This unusually high exponent (0.95) can be explained by their high
daytime activity levels, relative to all birds (0.67), whose scaling is likely influenced largely by surface-area related heat and water loss. Their high
exponent also hints that they are perhaps released from some of the evolutionary constraints that other birds face.
Even though nighttime energy expenditure is only a small component of daily energy expenditure, it can be a limiting factor to survival, because with no
nighttime energy intake, hummingbirds need to carefully ration their limited nighttime energy stores. I discovered that hummingbirds can manage NEE on a finer
scale than originally thought, by using a combination of shallow and deep torpor, while other bird species have only been described to use one or the other.
Hummingbirds’ ability to use torpor at varying levels, and the flexibility in their daily energy budgets, suggest the importance of even small adjustments in
energy expenditure. Collectively, these data suggest that hummingbirds’ energetic demands in their nectarivore niche require constant and precise management that
might make them flexible to rapid and short-term environmental changes, but could make them susceptible to prolonged environmental shifts.
Several toxins interfere in blood coagulation and platelet aggregation. We study the structure-function relationships and mechanism of anticoagulant and antiplatelet proteins, particularly PLA2 enzymes. The strongly anticoagulant PLA2 binds to factor Xa and specifically inhibits the prothrombinase complex. Based on the anticoagulant site of PLA2, we are attempting to identify the functional sites of coagulation factors. We also determine the structure of venom prothrombin activators that are structural and functional homologs of coagulation factors. Based on their structures, we are designing anticoagulant peptides.
The study of venoms and toxins is relevant to a number of scientific fields. Clinical toxinology studies the impact of bites and stings from venomous organisms on humans. With the World Health Organization’s recent reinstatement of snakebite envenoming to the list of Neglected Tropical Diseases, clinical toxinology promises to be a growing area of research. Pharmacology, on the other hand, takes an interest in toxins (the constituents of venom) because of the fascinating structure-function relationships that influence their interaction with their targets. This perspective, including its application in “biodiscovery” – the search in nature for novel molecules for use in drug design or as investigational ligands – is properly considered an evolutionary outgrowth of ethnopharmacology, the ancient human practice of seeking medicines in the natural world. Yet another way of considering venoms and toxins is through the lens of evolutionary biology. The dynamic evolution of venom systems and their role in predator-prey interactions makes them a unique model system for studies of both molecular and ecological evolutionary patterns.
Are these various viewpoints best considered separately, or do we stand to gain key insights by combining them? In my research I have straddled all three of these subject areas and also consider venoms interesting subject material for work in the philosophy of biology and biosemiotics (the study of “sign relations” in nature). My belief is that our understanding can be greatly enhanced by treating venoms and their associated anatomy as the complex adaptive systems that they are. Thus, in this talk I will be jumping from perspective to perspective in order to give a flavour of the view of toxinology from the “interdisciplinary nowhere” that I inhabit.
The evolution and biogeography of various taxa in Peninsular India are of particular interest as this region, a Gondawanan fragment, is critical to our understanding of historical biogeography in the Oriental realm. Over the past decade, molecular tools have enabled testing of alternative historical scenarios of faunal exchange and consequent biogeographic patterns. The snakes of Peninsular India, despite their spectacular diversity, remain poorly known with regard to their biogeographic affinities. While most Indian snakes are considered to be Malayan relicts, this hypothesis remains unexplored. Hence, we explored historical patterns of dispersal and diversification within Peninsular India using two distantly related snakes with broad differences in ecology and biology; an arboreal, non-venomous genus, Ahaetulla (vine snakes), belonging to the family Colubridae, and the genus Trimeresurus (pit vipers) a group of terrestrial and arboreal, venomous snakes belonging to the family Viperidae.
First, using an extensive taxon sampling of snakes from Peninsular India and adjoining Northeast India, we delimited species using a coalescent method and a multi-criteria approach including genes, geography and morphology. The results reveal the presence of several new lineages of snakes, including morphologically cryptic lineages, in both genera. Second, using mitochondrial and nuclear DNA, we reconstructed the phylogenies of the delimited lineages. In vine snakes, we discovered a deeply divergent lineage from the southern Western Ghats, that is sister to all remaining members of Ahaetulla. In Trimeresures, we recovered multiple clades, one of which is predominantly peninsular Indian with a few Southeast Asian lineages. Third, we tested for clade congruence in patterns of diversification and dispersal using ancestral range reconstruction of geographical ranges. In contrast to earlier hypotheses, Peninsular India emerged as a centre of snake diversification and Western Ghats as a major centre of in-situ radiation for both clades. Patterns of dispersal show signatures of congruence and contrast between the clades, with the Western Ghats
acting as a major source for colonisation of ancestral lineages into the arid regions in Peninsular India and adjoining Sri Lanka as well as Southeast Asian regions.
In 2004 Poland joined European Union as a new Member State. In terms of nature conservation it meant following the guidelines of Habitats Directive (Council Directive 92/43/EEC of 21 May 1992 on the conservation of natural habitats and of wild fauna and flora) and implementing them into national law. Main subjects of new regulations was designation of the network of protected areas known as NATURA 2000 and preparation of management plans for habitats and species listed in Annex II of Habitat Directive. One of the pilot species chosen for management plan preparation, among others was Great Crested Newt (Triturus cristatus). This amphibian is widespread in Europe but has suffered severe declines in most of the 37 known range countries. It is listed as Least Concern in the IUCN Red List.
I want to present the approach, work and result we obtained during management plan preparation. The core part of a plan is holistic approach to the conservation measures. We followed the scheme: threat-aim-activities. After presenting outcome of our work I want to show also how the guidelines of the plan are meeting the reality.