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1.
PeerJ ; 11: e14906, 2023.
Article in English | MEDLINE | ID: mdl-36935908

ABSTRACT

Illegal fishing in small-scale fisheries is a contentious issue and resists a straightforward interpretation. Particularly, there is little knowledge regarding cooperative interactions between legal and illegal fishers and the potential effects on fisheries arising from these interactions. Taking the Chilean king crab (Lithodes santolla; common name centolla) fishery as a case study, our goal is twofold: (i) to model the effect of illegal-legal fishers' interactions on the fishery and (ii) analyze how management and social behavior affect fishery's outcomes. We framed the analysis of this problem within game theory combined with network theory to represent the architecture of competitive interactions. The fishers' system was set to include registered (legal) fishers and unregistered (illegal) fishers. In the presence of unregistered fishers, legal fishers may decide to cooperate (ignoring the presence of illegal fishers) or defect, which involves becoming a "super fisher" and whitewashing the captures of illegal fishers for a gain. The utility of both players, standard fisher and super fisher depend on the strategy chosen by each of them, as well as on the presence of illegal fishers. The nodes of the network represent the legal fishers (both standard and super fishers) and the links between nodes indicate that these fishers compete for the resource, assumed to be finite and evenly distributed across space. The decision to change (or not) the adopted strategy is modeled considering that fishers are subjected to variable levels of temptation to whitewash the illegal capture and to social pressure to stop doing so. To represent the vital dynamics of the king crab, we propose a model that includes the Allee effect and a term accounting for the crab extraction. We found that the super fisher strategy leads to the decrease of the king crab population under a critical threshold as postulated in the tragedy of the commons hypothesis when there are: (i) high net extraction rates of the network composed of non-competing standard fishers, (ii) high values of the extent of the fishing season, and (iii) high density of illegal fishers. The results suggest that even in the presence of super fishers and illegal fishers, the choice of properly distributed fishing/closure cycles or setting an extraction limit per vessel can prevent the king crab population from falling below a critical threshold. This finding, although controversial, reflects the reality of this fishery that, for decades, has operated under a dynamic in which whitewashing and super fishers have become well established within the system.


Subject(s)
Anomura , Fisheries , Hunting , Animals , Chile , Humans , Hunting/legislation & jurisprudence , Models, Theoretical
2.
Sci Total Environ ; 634: 941-950, 2018 Sep 01.
Article in English | MEDLINE | ID: mdl-29660888

ABSTRACT

In developing countries, the protection of biodiversity and ecosystem services (ES) rests on the hands of millions of small landowners that coexist with large properties, in a reality of highly unequal land distribution. Guiding the effective allocation of ES-based incentives in such contexts requires researchers and practitioners to tackle a largely overlooked question: for a given targeted area, will single large farms or several small ones provide the most ES supply? The answer to this question has important implications for conservation planning and rural development alike, which transcend efficiency to involve equity issues. We address this question by proposing and testing ES supply-area relations (ESSARs) around three basic hypothesized models, characterized by constant (model 1), increasing (model 2), and decreasing increments (model 3) of ES supply per unit of area or ES "productivity". Data to explore ESSARs came from 3384 private landholdings located in southern Chile ranging from 0.5ha to over 30,000ha and indicators of four ES (forage, timber, recreation opportunities, and water supply). Forage provision best fit model 3, which suggests that targeting several small farms to provide this ES should be a preferred choice, as compared to a single large farm. Timber provision best fit model 2, suggesting that in this case targeting a single large farm would be a more effective choice. Recreation opportunities best fit model 1, which indicates that several small or a single large farm of a comparable size would be equally effective in delivering this ES. Water provision fit model 1 or model 2 depending on the study site. The results corroborate that ES provision is not independent from property area and therefore understanding ESSARs is a necessary condition for setting conservation incentives that are both efficient (deliver the highest conservation outcome at the least cost) and fair for landowners.

3.
PLoS One ; 11(5): e0155019, 2016.
Article in English | MEDLINE | ID: mdl-27167737

ABSTRACT

Growing concern about the loss of ecosystem services (ES) promotes their spatial representation as a key tool for the internalization of the ES framework into land use policies. Paradoxically, mapping approaches meant to inform policy decisions focus on the magnitude and spatial distribution of the biophysical supply of ES, largely ignoring the social mechanisms by which these services influence human wellbeing. If social mechanisms affecting ES demand, enhancing it or reducing it, are taken more into account, then policies are more effective. By developing and applying a new mapping routine to two distinct socio-ecological systems, we show a strong spatial uncoupling between ES supply and socio-ecological vulnerability to the loss of ES, under scenarios of land use and cover change. Public policies based on ES supply might not only fail at detecting priority conservation areas for the wellbeing of human societies, but may also increase their vulnerability by neglecting areas of currently low, but highly valued ES supply.


Subject(s)
Conservation of Natural Resources , Ecosystem , Adaptation, Physiological , Argentina , Geography , Humans , Principal Component Analysis
4.
Rev. colomb. cienc. pecu ; 25(1): 46-55, ene.-mar. 2012. ilus, tab
Article in Spanish | LILACS | ID: lil-639887

ABSTRACT

Factors determining the adoption of water conservation practices are specific to the study sites and need to be identified to develop local policies. Objective: identify factors that determine the adoption of water conservation practices in cattle farms in a high Andean watershed, given that this area is considered a conservation priority in Caldas province, Colombia. Methods: in this study, five factor categories related to the adoption of conservation practices were used as a reference. The study quantified variables obtained by survey from February to April 2009. A total of 69 farmers were surveyed. A Logit regression model was used to explain adoption of conservation practices. Significant variables were plotted to measure their effect on the probability of practice adoption. Results: model results show that although factors related to biophysical properties (NAC and LIM) along with risk and uncertainty factors (TEN and CAP) were significant, other factors are also significant in the study area, such as those related with decision makers (EDU) and farm resources (TAM). Conclusions: regarding the effect of significant variables on the probability of adoption, it is not necessary to reach a conclusion about which ones are most important; however, the model results and the determination of the effects offer keys to direct the conservation actions in the area, allowing to generate recommendations in this regard that can be used as reference in cattle areas around high Andean aquatic ecosystems.


Los factores que determinan la adopción de prácticas de conservación a nivel agropecuario son específicos de los sitios de estudio e identificarlos es necesario para tomar decisiones a nivel local. Objetivo: en el presente trabajo, tomando como referencia cinco categorías de factores relacionados con la adopción de prácticas de conservación, se buscó identificar aquellos factores que determinan la adopción de prácticas de conservación del agua en sistemas ganaderos de una cuenca alto andina con prioridad de conservación en el departamento de Caldas (Colombia). Métodos: en el estudio se cuantificaron algunas variables, obtenidas a través de una encuesta realizada entre Febrero-Abril del 2009 a 69 tomadores de decisión de predios ganaderos del sector, las cuáles fueron incluidas en un modelo de regresión Logit para explicar la adopción. Las variables significativas fueron graficadas para medir el efecto que ejercen sobre la probabilidad de adopción. Resultados: los resultados del modelo muestran que aunque los factores relacionados con aspectos biofísicos de los predios (NAC y LIM) y los factores de riesgo e incertidumbre (TEN y CAP) son significativos, en la zona de estudio existen otros factores que también son significativos, como los relacionados con los tomadores de decisión (EDU) y los recursos de dotación de los predios (TAM). Conclusiones: con relación al efecto de las variables significativas sobre la probabilidad de adopción, no es preciso llegar a una conclusión sobre cuál o cuáles son las más importantes, sin embargo, los resultados del modelo y la determinación de los efectos, ofrecen elementos para dirigir las acciones de conservación en la zona, permiten generar algunas recomendaciones en tal sentido y pueden servir de referente en zonas ganaderas relacionadas con ecosistemas acuáticos alto andinos.


Os fatores que determinam a adoção de práticas de conservação agrícola são específicos dos locais de estudo. Objetivo: usando como referência 5 categorias de fatores relacionados com a adoção de práticas de conservação ao nível pecuário, neste estudo tentou se identificar os fatores que determinam a adoção de práticas de conservação da água nos sistemas pecuários da bacia alta do rio Guarinó em Caldas. Métodos: no estudo quantificaram-se algumas variáveis obtidas através de enquetes realizados desde Fevereiro até Abril do 2009, para 69 tomadores de decisão, as quais foram incluídas em um modelo de regressão logística para explicar a adoção. As variáveis significativas foram plotadas para medir o efeito que exercem sobre a probabilidade de adoção. Resultados: os resultados do modelo demonstram que embora os fatores relacionados com aspectos biofísicos dos prédios (NAC e LIM) e os fatores de risco e incerteza (TEN e CAP) foram significativos, na zona de estudo existem outros fatores que também foram significativos: os que tem relação com os tomadores de decisão (EDU) e os recursos de dotação dos prédios (TAM). Conclusões: em relação ao efeito das variáveis significativas sobre a probabilidade de adoção, não é preciso chegar a uma conclusão sobre qual ou quais são as de maior importância, entretanto, os resultados do modelo e a determinação dos efeitos, oferecem elementos para dirigir as ações de conservação da região que permitem gerar algumas recomendações. Nesse sentido, podem servir como referência em regiões pecuárias que tenham relação com ecossistemas aquáticos andinos.

5.
J Environ Manage ; 97: 38-45, 2012 Apr 30.
Article in English | MEDLINE | ID: mdl-22325581

ABSTRACT

Investment in natural capital restoration is increasing as a response to the widespread ecological degradation of dryland forests. However, finding efficient mechanisms to promote restoration among private landowners is a significant challenge for policy makers with limited financial resources. Furthermore, few attempts have been made to evaluate the costs and benefits of restoration interventions even though this information is relevant to orient decision making. Hence, our goal was to estimate the benefits and costs of dryland forest restoration by means of reforestation with native trees in a study area in central Chile. To determine benefits we applied a Contingent Valuation questionnaire that allowed for the calculation of willingness to pay measures. Restoration costs were calculated based on market prices following existing technical recommendations developed for the study area. The results showed that the restoration project had a negative NPV irrespective of the discount rate applied in the analysis. Thus, the NPV varied between -US$71,000 and -US$258,000. The NPV attained positive results only for negative discount rates (US$15,039 for -2%) and only when the national subsidy available for forest restoration was taken into account. This shows that landowners in Colliguay do not have incentives for carrying out restoration interventions due to a classic market failure: that in which ecosystems are mismanaged because many of their benefits are externalities from the perspective of landowners. Overall, these results stress the need for developing new compensation mechanisms and enhancing those in existence, with the aim of making restoration competitive with other land uses.


Subject(s)
Conservation of Natural Resources/economics , Forestry/economics , Trees , Biodiversity , Chile , Cost-Benefit Analysis , Forestry/methods
6.
Ambio ; 39(7): 463-6, 2010 Nov.
Article in English | MEDLINE | ID: mdl-21090000

ABSTRACT

Southern Chile encompasses one of the most extensive fjord regions of the world, the Patagonia, currently exposed to natural and anthropogenic perturbations. These fjord ecosystems provide important services to humans, which have not been adequately measured and valued. As a consequence, ecosystem services are commonly ignored in public policy design and in the evaluation of development projects. Here we tackle questions that are highly relevant for the nation's development, namely (1) understanding fjord functioning, and (2) developing management strategies based on ecosystem services, in order to secure simultaneous and adequate use of these ecosystems which area influenced by ecological (e.g., biogeochemical) and productive (e.g., aquaculture, fisheries) processes. We also seek to strengthen the analysis of fjord ecosystem value from the economical (including coastal zoning), socio-cultural, institutional, and governmental points of view. In addition, the investigation of current and future effects of climate change on this large region offers a unique opportunity to understand the social and economic consequences of a global phenomenon at local to regional scales. Biogeochemical and socio-economic models will be used to simulate future scenarios under a gamut of management options.


Subject(s)
Conservation of Natural Resources , Ecosystem , Environmental Policy , Environmental Pollution , Chile , Geography , Humans , Pacific Ocean
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