Displaying 16 - 30 of 39 records found.
| Title | Type Created |
|---|---|
a model of robustness tradeoffs in social-ecological system | Model |
| feedback control systems in general exhibit inherent robustness-fragility tradeoffs. that is, by becoming very robust to a given set of disturbances for maintaining stability, feedback systems necessarily introduce hidden fragilities to disturbances outside this set. even a small unanticipated disturbance can initiate cascading system-wide failures as a result. the model presented here demonstrates this phenomenon. in anderies et al. (2012), an agricultural production system is illustrated as... | 09 Aug 2016 |
robustness and resilience across scales: migration and resource degradation in the prehistoric u.s. southwest | Model |
| this is a simple model that integrates 1) resource-population dynamics, 2) population migration, and 3) spatial heterogeneity in biophysical conditions (i.e., soi fertility). the reference article, anderies and hegmon (2011), gives the following abstract of the model. "migration is arguably one of the most important processes that link ecological and social systems across scales. humans (and other organisms) tend to move in pursuit of better resources (both social and environmental). such... | 09 Aug 2016 |
the evolution of social norms in common property resource use | Model |
| this is a simple evolutionary game model (based on replicator equations) that couples evolution of users' social norms and renewable resource dynamics. the reference article, sethi and somanathan (1996), provides the following overview of the model. " the problem of extracting commonly owned renewable resources is examined within an evolutionary-game-theoretic framework. it is shown that cooperative behavior guided by norms of restraint and punishment may be stable in a well-defined... | 09 Aug 2016 |
regime shifts in a socio-ecological model of farmland abandonment | Model |
| this is a simple model with reciprocal feedbacks between social and ecological dynamics of farmland abandonment. with the rising urbanization, human migration to urban centers have increased significantly around the globe. one notable consequence of this migration pattern is that mountainous forests that had been traditionally cleared for farming are increasingly becoming abandoned. as a result, such lands likely become forests again through natural regeneration. these trends may induce two... | 09 Aug 2016 |
the coupled dynamics of human socio-economic choice and lake water system: the interaction of two sources of nonlinearity | Model |
| here, we present a model of the coupled dynamics between human socioeconomic choice (between cooperative and non-cooperative collective action) and nutrient loading input level into a lake water system. suzuki and iwasa (2008) explains the model as the following. "in the model, many players choose one of the two options: a cooperative and costly option with low phosphorus discharge, and an economical option with high phosphorus discharge. the choice is affected by an economic cost, a... | 09 Aug 2016 |
conflict between groups of players in coupled socio-economic and ecological dynamics | Model |
| this is a model for the coupled dynamics of conflict between two different user groups regarding their socioeconomic choice (between cooperative and non-cooperative collective action) and nutrient loading input level into a lake water system. suzuki and iwasa (2009),gives the following overview of the model. "conflict among multiple groups is a major source of difficulty in environmental conservation. people are often divided into various groups that have different social factors,... | 09 Aug 2016 |
paradox of marine protected areas: suppression of fishing may cause species loss | Model |
| this is a simple model of a prey-predator system in two areas, one of which receives fishing activity (fishing ground) and another that does not (mpa: marine protected area). takashina et al. 2012 gives the following description of the model. "a number of fish and invertebrate stocks have been depleted by overexploitation in recent years. to address this, marine protected areas (mpas) are often established to protect biodiversity and recover stocks. we analyzed the potential impact of... | 09 Aug 2016 |
non-linear dynamics of population and natural resources: the emergence of different patterns of development | Model |
| this model explores the long-term dynamic interaction between the exploitation of natural resources and population growth. this is a variant of brander and taylor (1998). the reference article, d'alessandro (2007), gives the following description of the model. "two new assumptions are introduced: i) the disaggregation of the ecological complex into two different resources; ii) irreversibility --namely, an inexorable tendency to exhaustion when the renewable resource stock is below a... | 09 Aug 2016 |
tourists and traditional divers in a common fishing ground | Model |
| a social-ecological model of a fishing ground open to eco-tourism is presented here. to assess the impact of introducing eco-tourism on the welfare of the fishing association and on the resource level, lee and iwasa (2011) constructs a model in which the fishing association charges an entrance fee to tourists. the level of the fee is chosen to regulate tourist number as well as maximing benefits accrued to the fishing association (combined revenue from tourism and conventional fishing by... | 09 Aug 2016 |
subtle global bifurcation with dramatic ecological consequences in a simple population model | Model |
| this model presents an example of a global bifurcation (a heteroclinic connection). the model is a three-dimensional system with two resources and a single consumer, where one of the resources is fixed and the other is reproductive. by assuming that, for all values of resource consumers (c) below its carrying capacity (k), the fixed resource facilitates the consumption of the reproductive resource, the system can be reduced to a two-dimensional system. the reference article, vandermeer and king... | 09 Aug 2016 |
the inevitability of surprise in agroecosystems | Model |
| this is a simple model of competition between noxious and benigne weeds in an agroecosystem based on predator-prey dynamics. the interesting aspect of this model is that it demonstrates the inevitability of surprises in system behavior - meaning that for some systems, early warning signals (e.g, increased variance or autocorrelatin) are almost non-existent prior to critical transitions in systems. the reference article, vandermeer (2011), gives the following overview. "many critical... | 09 Aug 2016 |
the discrete logistic | Model |
| the logistic is the simplest representation of population dynamics that contains a minimum level of biological realism. if we imagine a population of individuals at time t, the number of individuals in the next period (periods can range from seconds to days to decades depending on the organism) is the number of individuals now plus the number of births minus the number of deaths. if we assume in the simplest case there are no environmental constraints on births or deaths, then it is reasonable... | 09 Aug 2016 |
living in a network of scaling cities and finite resources | Model |
| a modified lotka-volterra system in which multiple consumers and resource systems are connected by both consumer-consumer and consumer-resource links. consumers represent cities, and thus exhibit nonlinear scaling behaviors as population increases w.r.t. harvest rate and harvest conversion efficiency. populations can also migrate between cities along a welfare-dependent gradient. analysis of the model for a simple dyadic network reveals that the basic lotka-volterra formulation can lead to... | 30 Sep 2016 |
ecological-economic model for optimal control of fire-driven, semi-arid rangelands | Model |
| this is an ecological-economic model that endogenizes discontinuous change between states of fire-driven, semi-arid rangelands which may exist in varying degrees as grassland and woodlands depending partly on the given soil conditions. more sandy soils will result in woodlands, whereas clay soils will more likely result in grasslands. one of the critical features of this model is the existence and impact of fires on these different types of rangelands. grasslands may build up biomass and create... | 01 Oct 2016 |
malthusian population growth and crisis in pre-industrial agrarian societies | Model |
| most models of malthusian population dynamics specify logistic growth to a carrying capacity, but the historical record of agrarian societies strongly suggests that repeated cycles of overshoot and collapse (so-called "malthusian crises") are endogenous to population dynamics (see nefedov, 2013 for details and citations). in this model, nefedov (2013) explicitly models harvest surplus production as the carrying capacity of an agricultural population. when population pressure drives... | 01 Oct 2016 |