The ghost of past species occurrence: improving species distribution models for presence-only data

1. Model-based approaches have been used increasingly in conservation biology over recent years. Species presence data used for predictive species distribution modelling are abundant in natural history collections, whereas reliable absence data are sparse, most notably for vagrant species such as butterflies and snakes. As predictive methods such as generalized linear models (GLM) require absence data, various strategies have been proposed to select pseudo-absence data. However, only a few studies exist that compare different approaches to generating these pseudo-absence data. 2. Natural history collection data are usually available for long periods of time (decades or even centuries), thus allowing historical considerations. However, this historical dimension has rarely been assessed in studies of species distribution, although there is great potential for understanding current patterns, i.e. the past is the key to the present. 3. We used GLM to model the distributions of three 'target' butterfly species, Melitaea didyma, Coenonympha tullia and Maculinea teleius, in Switzerland. We developed and compared four strategies for defining pools of pseudo-absence data and applied them to natural history collection data from the last 10, 30 and 100 years. Pools included: (i) sites without target species records; (ii) sites where butterfly species other than the target species were present; (iii) sites without butterfly species but with habitat characteristics similar to those required by the target species; and (iv) a combination of the second and third strategies. Models were evaluated and compared by the total deviance explained, the maximized Kappa and the area under the curve (AUC). 4. Among the four strategies, model performance was best for strategy 3. Contrary to expectations, strategy 2 resulted in even lower model performance compared with models with pseudo-absence data simulated totally at random (strategy 1). 5. Independent of the strategy model, performance was enhanced when sites with historical species presence data were not considered as pseudo-absence data. Therefore, the combination of strategy 3 with species records from the last 100 years achieved the highest model performance. 6. Synthesis and applications. The protection of suitable habitat for species survival or reintroduction in rapidly changing landscapes is a high priority among conservationists. Model-based approaches offer planning authorities the possibility of delimiting priority areas for species detection or habitat protection. The performance of these models can be enhanced by fitting them with pseudo-absence data relying on large archives of natural history collection species presence data rather than using randomly sampled pseudo-absence data.

Angiotensinergic innervation of the kidney: present knowledge and its significance.

Intrarenal neurotransmission implies the co-release of neuropeptides at the neuro-effector junction with direct influence on parameters of kidney function. The presence of an angiotensin (Ang) II-containing phenotype in catecholaminergic postganglionic and sensory fibers of the kidney, based on immunocytological investigations, has only recently been reported. These angiotensinergic fibers display a distinct morphology and intrarenal distribution, suggesting anatomical and functional subspecialization linked to neuronal Ang II-expression. This review discusses the present knowledge concerning these fibers, and their significance for renal physiology and the pathogenesis of hypertension in light of established mechanisms. The data suggest a new role of Ang II as a co-transmitter stimulating renal target cells or modulating nerve traffic from or to the kidney. Neuronal Ang II is likely to be an independent source of intrarenal Ang II. Further physiological experimentation will have to explore the role of the angiotensinergic renal innervation and integrate it into existing concepts.

Colonialism, Elite Formation and Corruption

This paper argues that corruption in developing countries has deep historical roots; going all the way back to the characteristics of their colonial experience. The degree of European settlement during colonial times is used to dfferentiate between types of colonial experience, and is found to be a powerful explanatory factor of present-day corruption levels. The relationship is non-linear, as higher levels of European settlement resulted in more powerful elites (and more corruption) only as long as Europeans remained a minority group in the total population.

Institutions, Property Rights, and Economic Development in Historical Perspective

Institutions, and more speci cally private property rights, have come to be seen as a major determinant of long-run economic development. We evaluate the case for property rights as an explanatory factor of the Industrial Revolution and derive some lessons for the analysis of developing countries today. We pay particular attention to the role of property rights in the accumulation of physical capital and the production of new ideas. The evidence that we review from the economic history literature does not support the institutional thesis.

The Marginal Productivity Theory Of The Price Of Capital: An Historical Perspective On The Origins Of The Codswallop

Although it might have been expected that, by this point in time, the unacceptability of the marginal productivity theory of the return on capital would be universally agreed, that is evidently not the case. Popular textbooks still propound the dogma to the innocent. This note is presented in the hope that a succinct indication of the origins of the theory it will contribute to a more general appreciation of the unrealistic and illogical nature of this doctrine.

The past, present and future of central banking

The financial crisis, on the one hand, and the recourse to ‘unconventional’ monetary policy, on the other, have given a sharp jolt to perceptions of the role and status of central banks. In this paper we start with a brief ‘contrarian’ history of central banks since the second world war, which presents the Great Moderation and the restricted focus on inflation targeting as a temporary aberration from the norm. We then discuss how recent developments in fiscal and monetary policy have affected the role and status of central banks, notably their relationships with governments, before considering the environment central banks will face in the near and middle future and how they will have to change to address it.

Recent plant diversity changes on Europe's mountain summits.

In mountainous regions, climate warming is expected to shift species' ranges to higher altitudes. Evidence for such shifts is still mostly from revisitations of historical sites. We present recent (2001 to 2008) changes in vascular plant species richness observed in a standardized monitoring network across Europe's major mountain ranges. Species have moved upslope on average. However, these shifts had opposite effects on the summit floras' species richness in boreal-temperate mountain regions (+3.9 species on average) and Mediterranean mountain regions (-1.4 species), probably because recent climatic trends have decreased the availability of water in the European south. Because Mediterranean mountains are particularly rich in endemic species, a continuation of these trends might shrink the European mountain flora, despite an average increase in summit species richness across the region.

An issue with own-rates: Keynes borrows from Sraffa , Sraffa criticises Keynes, and present-day commentators get hold of the wrong end of the stick

Scholars who in recent years have studied the Sraffa papers held in the Wren Library of Trinity College, Cambridge, have concluded from Sraffa’s critical (but unpublished) observations on Chapter 17 of Keynes’s General Theory that he rejected Keynes’s central proposition that the rate of interest on money may come to ‘rule the roost’, thus dragging the economy into recession. While Sraffa does indeed express dissatisfaction with Chapter 17, the commentators have, we believe, misunderstood his concern: we suggest that he was unhappy with the ‘own-rates’ terminology employed by Keynes rather than with the substance of the theory developed in Chapter 17.

Tractable Consumer Choice

We derive a rational model of separable consumer choice which can also serve as a behavioral model. The central construct is [lambda] , the marginal utility of money, derived from the consumer's rest-of-life problem. We present a robust approximation of [lambda], and show how to incorporate liquidity constraints, indivisibilities and adaptation to a changing environment. We fi nd connections with numerous historical and recent constructs, both behavioral and neoclassical, and draw contrasts with standard partial equilibrium analysis. The result is a better grounded, more flexible and more intuitive description of consumer choice.

The Emperor Has New Clothes: Empirical Tests of Mainstream Theories of Economic Growth

Modern macroeconomic theory utilises optimal control techniques to model the maximisation of individual well-being using a lifetime utility function. Agents face choices over current and future consumption (with resultant implied savings decisions) seeking to maximise the present value of current plus future well-being. However, such inter-temporal welfare-maximising assumptions remain empirically untested. In the work presented here we test whether welfare was in (historical) fact maximised in the US between 1870-2000 and find empirical support for the optimising basis of growth theory, but only once a comprehensive view of what constitutes a country’s wealth or capital is taken into account.

Modelling Housing Prices using a Present Value State Space Model

This paper introduces a State Space approach to explain the dynamics of rent growth, expected returns and Price-Rent ratio in housing markets. According to the present value model, movements in price to rent ratio should be matched by movements in expected returns and expected rent growth. The state space framework assume that both variables follow an autoregressive process of order one. The model is applied to the US and UK housing market, which yields series of the latent variables given the behaviour of the Price-Rent ratio. Resampling techniques and bootstrapped likelihood ratios show that expected returns tend to be highly persistent compared to rent growth. The Öltered expected returns is considered in a simple predictability of excess returns model with high statistical predictability evidenced for the UK. Overall, it is found that the present value model tends to have strong statistical predictability in the UK housing markets.