On the sympatric evolution and evolutionary stability of coexistence by relative nonlinearity of competition

If two species exhibit different nonlinear responses to a single shared resource, and if each species modifies the resource dynamics such that this favors its competitor, they may stably coexist. This coexistence mechanism, known as relative nonlinearity of competition, is well understood theoretically, but less is known about its evolutionary properties and its prevalence in real communities. We address this challenge by using adaptive dynamics theory and individual-based simulations to compare community stabilization and evolutionary stability of species that coexist by relative nonlinearity. In our analysis, evolution operates on the species' density-compensation strategies, and we consider a trade-off between population growth rates at high and low resource availability. We confirm previous findings that, irrespective of the particular model of density dependence, there are many combinations of overcompensating and undercompensating density-compensation strategies that allow stable coexistence by relative nonlinearity. However, our analysis also shows that most of these strategy combinations are not evolutionarily stable and will be outcompeted by an intermediate density-compensation strategy. Only very specific trade-offs lead to evolutionarily stable coexistence by relative nonlinearity. As we find no reason why these particular trade-offs should be common in nature, we conclude that the sympatric evolution and evolutionary stability of relative nonlinearity, while possible in principle, seems rather unlikely. We speculate that this may, at least in part, explain why empirical demonstrations of this coexistence mechanism are rare, noting, however, that the difficulty to detect relative nonlinearity in the field [...]Comment: PLOS ONE, in pres

Managing land use and land cover change in the biodiversity context with regard to efficiency, equality and ecological effectiveness

The introduction of conservation-friendly farming measures is an important tool for biodiversity conservation. Recently, a debate has started whether this money is spent effectively, i.e. whether it successfully contributes to conserve biodiversity in agricultural landscapes. Several types of criticism have been raised that are adequately responded by environmental policies leading to spatially and temporally heterogeneous habitats. However existing policies for species conservation are still designed to support one conservation measure only by paying an equal amount of compensation to all land-users carrying out the corresponding measure. Regarding ecological findings we firstly point out in which cases environmental policies have to be differentiated in space and time. Secondly, we analyse the necessary and sufficient conditions for transfer schemes to exist that are able to introduce a spatio-temporally heterogeneous land use and land cover type. Thirdly, we reveal that strategic considerations of land-owners limit efficiency and fairness considerations of the policy makers when determining the ecologically accurate payment scheme. However ' surprisingly ' if policy makers seek to minimise their budget required for implementing the desired policy goal, this at the same time guarantees that the individual profits of the land-owners (when performing with the desired policy goal) are as equal as feasible. --

Integrating econimic costs into the analysis of flexible conservation management strategies

Flexible conservation management, where measures are selected in each decision period and depending on the current state of the ecological system, are generally perceived as superior to fixed management, where the same measure is applied in each decision period independent of the current state of the system. In past comparisons of fixed and flexible conservation strategies the additional costs that arise only in flexible strategies have usually been ignored. In this paper we present a framework to integrate these 'costs of flexible management' into the evaluation of flexible conservation strategies. Using the example of an endangered butterfly species we demonstrate that the costs of flexible management may reverse the rank order of flexible and fixed conservation strategies, such that fixed strategies may lead to better ecological results than flexible ones for the same financial budget. --conservation,ecological-economic model,extinction,flexible management

An agglomeration payment for cost-effective biodiversity conservation in spatially structured landscapes

Compensation schemes in which land owners receive payments for voluntarily managing their land in a biodiversity-enhancing manner have become one of the most important instruments for biodiversity conservation worldwide. One key challenge when designing such schemes is to account for the spatial arrangement of habitats bearing in mind that for given total habitat area connected habitats are ecologically more valuable than isolated habitats. To integrate the spatial dimension in compensation schemes and based on the idea of an agglomeration bonus we consider a scheme in which land-owners only receive payments if managed patches are arranged in a specific spatial configuration. We compare the cost-effectiveness of agglomeration payments with spatially homogeneous payments on a conceptual level and for a real world case and find that efficiency gains of agglomeration payments are positive or zero but never negative. In the real world case, agglomeration payments lead to cost-savings of up to 70% compared to spatially homogeneous payments. --agglomeration bonus,biodiversity conservation,cost-effectiveness,ecologicaleconomic modelling,metapopulation,spatial heterogeneity

A model-based approach for designing cost-effective compensation payments for conservation of endangered species in real landscapes

An approach is present which integrates an economic and an ecological model for designing cost-effective compensation payments for conservation of endangered species in real landscapes. The approach is used to develop a cost-effective compensation payment scheme for conservation of an endangered butterfly species (Maculinea teleius) protected by the EU Habitats Directive in the region of Landau, Germany. The economic model determines the costs of relevant conservation measures mowing meadows at different times and frequencies - and the ecological model quantifies the effects of these mowing regimes on the butterfly population. By comparing the ecological effects of different mowing regimes, the cost-effective regime and the corresponding payments are determined as a function of the conservation budget. The results of the case study are used to analyse the effect of metapopulation dynamics on the cost-effectiveness of compensation payment schemes, to evaluate an existing scheme in the region of Landau and to draw conclusions for the institutional design of payment schemes. --Conservation,biodiversity,metapopulation,cost-effectiveness,ecological-economic modelling

Spatial connectedness imposes local‐ and metapopulation‐level selection on life history through feedbacks on demography

Dispersal evolution impacts the fluxes of individuals and hence, connectivity in metapopulations. Connectivity is therefore decoupled from the structural connectedness of the patches within the spatial network. Because of demographic feedbacks, local selection also drives the evolution of other life history traits. We investigated how different levels of connectedness affect trait evolution in experimental metapopulations of the two-spotted spider mite. We separated local- and metapopulation-level selection and linked trait divergence to population dynamics. With lower connectedness, an increased starvation resistance and delayed dispersal evolved. Reproductive performance evolved locally by transgenerational plasticity or epigenetic processes. Costs of dispersal, but also changes in local densities and temporal fluctuations herein are found to be putative drivers. In addition to dispersal, demographic traits are able to evolve in response to metapopulation connectedness at both the local and metapopulation level by genetic and/or non-genetic inheritance. These trait changes impact the persistence of spatially structured populations

Die letzte Stunde der Wahrheit: Armin Nassehi über rechts und links

Armin Nassehi: Die letzte Stunde der Wahrheit: Warum rechts und links keine Alternativen mehr sind und Gesellschaft ganz anders beschrieben werden muss. Hamburg: Murmann 2015. 978386774377

Wer soll den Menschen zum Guten erziehen? Kants pädagogisches Denken und pädagogisch denken mit Kant

This paper outlines and exposes the basic features of Kant’s pedagogical thinking, which accompanies his philosophical works, to make it prolific for today’s reflection on Pedagogy. First the introduction argues for how such an attempt can be justified in general. Then the explanations concentrate specifically on the educational problem Kant formulated in his anthropology, which consists in the fact that human beings must be educated to the good, but those who educate them are in turn human beings who themselves need such an education. To find a way to handle that problem the central question determined is: Who does Kant recommend as a teacher for educating people to be good

Merging Horizons: Possibilities of Immediate Understanding

Mit der philosophischen Hermeneutik formuliert Gadamer in seinem Hauptwerk Wahrheit und Methode eine ontologische Wende: Sein, das verstanden werden kann, ist Sprache. Wenn das Verstehen von Texten oder Traditionen gelingt, spricht er von einer Horizontverschmelzung. Im ersten Teil untersucht dieser Artikel Gadamers Konzept des Verstehens mittels eines Vergleichs zu Derridas Dekonstruktion: Wie können wir sicher sein, dass wir wirklich einander und nicht bloß uns selbst verstehen? Der zweite Teil geht mit Gadamer über ihn hinaus und weist Momente des sozialen Lebens auf, in denen Verstehen scheinbar unmittelbar gelingt. Das Beispiel des Lachens zeigt, dass unsere Sprache nicht an Worten ihre Grenze findet und es Momente gibt, in denen wir einander unmittelbar verstehen. Diese Momente erweitern die Möglichkeiten unserer Sprache: Indem wir ihnen Raum lassen, erhöhen wir die Chance für ein gelingendes Verstehen – sowohl im wissenschaftlichen Kontext der Psychoanalyse und Philosophie als auch in alltäglicher Kommunikation.From the philosophical hermeneutics Gadamer developed in his main work Truth and Method an ontological change was formulated: Being that can be understood is language. He talks about a fusion of horizons if understanding of texts or traditions is to succeed. First, this article examines Gadamer’s concept of understanding by contrasting it with Derrida’s deconstruction: How can we be sure that we really understand each other and not merely ourselves? Second, going beyond Gadamer, moments of social life are to be demonstrated where understanding succeeds immediately. The example of laughter clarifies that words are not the ultimate boarder of language. There are moments showing us a connection between each other in an almost immediate way. They expand the possibilities of our language for a successful understanding: Leaving room for them to happen increases the chance of understanding – in the scientific context of psychoanalysis and philosophy as well as in everyday communication