Just as some species are used as model systems in organismal biology (e.g., physiology, genetics), many ecosystems are commonly used as model systems in ecology. Salt marshes, for instance, are great ...models to perform manipulative field experiments, and thus, were historically used to understand the drivers of community and ecosystem function. Decades of experimental work, indeed, made a strong contribution to community ecology as a discipline, but most of the emerged hypotheses and models were grounded in a few sites. When studies from new sites came onboard, looking to enlarge generalities, their results challenged the prevailing ideas. Here, we review more than 25 years of intense experimentation in South West Atlantic salt marshes, which helped not only to increase the knowledge about salt marsh functioning, but also to expand this knowledge beyond salt marshes helping to refine community and ecosystem function theory. We show that results coming from SW Atlantic marshes significantly contribute to understand 1) the separate and interactive effect of biotic and abiotic stress for species distribution and even for ecosystem stability, 2) the integrated role of species that can function as ecosystem engineers and as consumers, 3) the balance between stochastic and deterministic forces as drivers of community structure and 4) the regulation of cross-ecosystem fluxes. Nevertheless, we believe SW Atlantic salt marshes still have a lot more to offer, not only as conceptual models that help satisfy our intellectual curiosity, but also as key ecosystems that provide valuable benefits to our societies.
Climate change is generating extreme climate events, affecting ecosystem integrity and function directly through increases in abiotic stress and disturbance and indirectly through changes in the ...strength of biotic interactions. As consumers play an essential role in ecosystem functioning and have been shown to be highly sensitive to climate conditions, improved understanding of their role under changing environmental conditions is necessary to accurately anticipate climate change impacts on ecosystem integrity.
We evaluated if prolonged periods of extreme rain, a climatic event increasing in severity in many places around the world, and coincident increases in coastal flooding duration intensify consumer control of foundational salt marsh grass structure and quantify the consequences of flooding–consumer interactions on salt marsh range extent. To achieve this, we analysed: historic trends in crab grazing; crab numbers and activity in and out of rainy years on the low marsh edge; vegetation retreat from the low marsh edge at a plot scale in a manipulative exclosure experiment; vegetation retreat at a landscape‐scale from drone image analyses; and the vertical erosion in the lowest edge of an Argentinean salt marsh.
During flooded periods, crabs congregated in the low marsh, resulting in localized overgrazing of salt marsh grass and the rapid horizontal retreat of the marsh edge (98.5 cm on average). Salt marsh edge retreat resulted in a loss of ~4.5% of the total marsh area at the landscape scale. Inside crab exclusion plots, although grass cover declined slightly during the study period, the marsh edge did not retreat.
Synthesis. This study provides experimental evidence that an extreme climate event can destabilize a local consumer–prey interaction, indirectly triggering the range contraction of a critical coastal habitat. This work contributes to a growing body of research demonstrating that consumers can be unleashed, rather than suppressed, by extreme climatic events. Moreover, in cases where consumer fronts form during such events, the result can be not only local (along habitat edges) but also landscape‐scale extinction of foundation species and the habitats they biogenically create. Together, this supports the general idea that models of future climate scenarios integrate the indirect effects on ecosystem‐regulating food web interactions.
Resumen
El cambio climático está generando fenómenos climáticos extremos que afectan a la integridad y el funcionamiento de los ecosistemas directamente a través del aumento del estrés abiótico y los disturbios, e indirectamente a través de los cambios en la fuerza de las interacciones bióticas. Dado que los consumidores desempeñan un papel esencial en el funcionamiento de los ecosistemas, y se ha demostrado que son muy sensibles a las condiciones climáticas, es necesario mejorar la comprensión de su papel en condiciones ambientales cambiantes para anticipar con precisión los impactos del cambio climático en la integridad de los ecosistemas.
Aquí evaluamos si inundaciones más prolongadas provocadas por precipitaciones extremas, un fenómeno que se está dando en muchos lugares del mundo, intensifican el control de los consumidores sobre las plantas fundacionales de marismas afectando al funcionamiento de estos sistemas. Para ello, analizamos: (i) las tendencias históricas de precipitaciones y herbivoría de cangrejos; (ii) el número y la actividad de los cangrejos antes y durante años lluviosos en el borde de la marisma baja; (iii) el retroceso de la vegetación en el límite inferior de la marisma baja a escala de parcela en un experimento de exclusión de cangrejos; (iv) el retroceso de la vegetación a escala de paisaje a partir del análisis de imágenes tomadas con drones; y (v) la erosión vertical en el límite inferior de una marisma argentina.
Durante los periodos de inundación asociados a precipitaciones extremas, los cangrejos se congregaron en la marisma baja, lo que provocó un sobreconsumo de la vegetación y una rápida retracción de su límite inferior de distribución (98,5 cm en promedio). Este retroceso resultó en una pérdida de ~4,5% de la superficie total de la marisma a escala del paisaje. Dentro de las parcelas de exclusión de cangrejos, aunque la cobertura de plantas disminuyó ligeramente durante el periodo de estudio, el límite de distribución no se vio afectado.
Síntesis. Este estudio proporciona pruebas experimentales de que un evento climático extremo puede desestabilizar una interacción consumidor‐presa, desencadenando indirectamente la retracción del rango de un hábitat costero crítico. Este trabajo contribuye a un creciente cuerpo de investigación que demuestra que los consumidores pueden ser liberados, en lugar de suprimidos, por eventos climáticos extremos. Además, en los casos en los que se forman frentes de consumo durante esos fenómenos, el resultado puede ser no sólo locales (a escala de parche), sino también a escala de paisaje. En conjunto, esto apoya la idea más general de que los modelos de escenarios climáticos futuros necesitan incorporar los efectos directos e indirectos de las interacciones tróficas que regulan los ecosistemas.
Extremely atypical rainfall promotes longer flooding periods in salt marshes. This concentrates crab feeding activity in the low salt marsh edge, and propagates upwards, leading to die‐off vegetation zones and the retreat of the lower edge of salt marsh vegetation. Vegetation loss potentially accelerates shoreline vertical erosion, ultimately affecting the delivery of ecosystem services (i.e. shoreline protection and C accumulation).
Question
Does the effect of droppings and herbivory by wild guinea pigs on salt‐marsh vegetation vary across microhabitats?
Location
Upper salt marsh in the Mar Chiquita coastal lagoon (37°44′52″ S, ...57°26′6″ W, Argentina).
Methods
During autumn 2014, we performed a micro‐scale experiment manipulating droppings of wild guinea pigs (Cavia aperea). After 15 days, we compared the content of nutrients (i.e., NH4+, NO3−, and PO43−) in soil. Then, we started two factorial experiments in the high marsh, specifically one in marsh matrix (i.e., tall vegetation) and the other in open patches (i.e., short vegetation). Units were randomly assigned to different treatments (with and without herbivores and droppings). In early summer, we compared total plant cover, maximum height, above‐ground biomass, plant species richness and the composition of plant assemblages between treatments.
Results
Droppings increased the content of PO43− in soil by five times, but decreased the content of NO3−. Herbivory reduced total cover, plant height, and above‐ground biomass in the marsh matrix and the open patches. In the marsh matrix, droppings increased the total cover, whereas herbivory reduced the abundance of Spartina densiflora (cover and above‐ground biomass) and subordinate species (cover). Additionally, the cover of subordinate species was negatively associated with the cover of Spartina densiflora. Therefore, in the marsh matrix, by increasing light availability at the ground level, herbivory increased plant species richness, but with low cover of subordinate species. In contrast, in open patches, herbivory and droppings interacted to reduce plant species richness.
Conclusion
Herbivory by small mammals can control the above‐ground biomass, structure, and plant community composition of the high marsh, but non‐trophic mechanisms (droppings) can also affect community composition. Nonetheless, ecological impacts of small mammals depend on the context, because the magnitude and direction of trophic (herbivory) and non‐trophic (droppings) effects change across microhabitats.
Our understanding of trophic and non‐trophic effects of small herbivores remains relatively poor compared to that of large herbivores. Our experiment, simultaneously manipulating wild guinea pig herbivory and droppings in a salt marsh, shows that these factors can interact, and the magnitude and the direction of these trophic and non‐trophic ecological effects depend on the environmental context.
Physiological performance in lizards may be affected by climate across latitudinal or altitudinal gradients. In the coastal dune barriers in central‐eastern Argentina, the annual maximum ...environmental temperature decreases up to 2°C from low to high latitudes, while the mean relative humidity of the air decreases from 50% to 25%. Liolaemus multimaculatus, a lizard in the family Liolaemidae, is restricted to these coastal dunes. We investigated the locomotor performance of the species at 6 different sites distributed throughout its range in these dune barriers. We inquired whether locomotor performance metrics were sensitive to the thermal regime attributable to latitude. The thermal performance breadth increased from 7% to 82% with latitude, due to a decrease in its critical thermal minimum of up to 5°C at higher latitudes. Lizards from high latitude sites showed a thermal optimum, that is, the body temperature at which maximum speed is achieved, up to 4°C lower than that of lizards from the low latitude. At relatively low temperatures, the maximum running speed of high‐latitude individuals was faster than that of low‐latitude ones. Thermal parameters of locomotor performance were labile, decreasing as a function of latitude. These results show populations of L. multimaculatus adjust thermal physiology to cope with local climatic variations. This suggests that thermal sensitivity responds to the magnitude of latitudinal fluctuations in environmental temperature.
The thermal performance curves of Liolaemus multimaculatus varied with latitude. The thermal optimum temperature for maximum running speed decreased with latitude. Lizards from high latitude showed high bouts of performance at a widest range of temperature. Locomotor performance metrics were sensitive to thermal regime attributable to latitude.
Thermoregulation in ectotherms may be modulated by climatic variability across geographic gradients. Environmental temperature varies along latitudinal clines resulting in heterogeneous thermal ...resource availability, which generally induces ectotherms to use compensatory mechanisms to thermoregulate. Lizards can accommodate to ambient temperature changes through a combination of adaptive evolution and behavioral and physiological plasticity. We studied the thermal ecology of the endangered endemic lizard Liolaemus multimaculatus at six different sites distributed from the northern to southern areas of the distribution (700 km) in the Atlantic dune barriers of Argentina, and even including the borders areas of the distribution range. Environmental temperatures and relative humidity showed a strong contrast between northern and southern limits of the distribution range. The northern localities had operative temperatures (Te) above the range of preferred temperatures (Tset), instead, the southern localities had large proportion of Tes within the Tset. Although these different climatic conditions may constrain the thermal biology of L. multimaculatus, individuals from all localities maintained relatively similar field body temperatures (XTb = 34.07 ± 3.02 °C), suggesting that this parameter is conservative. Thermal preference partially reflected latitudinal temperature gradient, since lizards from the two southernmost localities showed the lowest Tsel and Tset. Thermoregulatory efficiency differed among localities, since E values in the northern localities (E = 0.53–0.69) showed less variability than those of southern localities (E = 0.14–0.67). Although L. multimaculatus employed a strategy of having a conservative Tb and being able to acclimatize the thermal preference to copes with latitudinal changes in the thermal environment, other local factors, such as ecological interactions, may also impose limitations to thermoregulation and this may interfered in the interpretation of results at wider spatial scale.
•We studied the thermal biology of Liolaemus multimaculatus in a latitudinal gradient.•Field body temperature were constant despite of latitude.•Individuals of different sites used similar thermal patches.•Preferred temperatures decreased up to 3 °C with latitude.•Changes in thermal preferences and behavioral plasticity improve thermoregulation.
Este trabajo comparte algunas de las reflexiones inspiradas por mis prácticas docentes en la muestra Identidades sin Límites: Un viaje de Humanidad en Tecnópolis (Buenos Aires, Argentina). La muestra ...busca estimular la deconstrucción y desnaturalización de ideas eurocéntricas y racistas en los visitantes, al exponerlos a distintos encuentros con la alteridad, al mismo tiempo que trabaja con la idea de identidad de manera implícita. Mi hipótesis es que aquellos visitantes pertenecientes a colectivos africanos, indígenas o relacionados a personas desaparecidas durante la última dictadura cívico-militar (1976-1983) veían sus experiencias reflejadas en distintas instancias del recorrido, de manera que la muestra de Identidades… facilitaría contextos de activación de marcas identitarias en el público de acuerdo con lo postulado por Claudia Briones.
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Previous issue date: ...2013-10-25
Conselho Nacional de Desenvolvimento Científico e Tecnológico
On the communication field, specifically on the studies about the creative processes of
websites interfaces, the departments of account planning and information architecture/user
experience design are responsible for the concept idealization and strategy for the creation and
development of the digital interface. During the creative process, one of the most relevant
factors is the focus on the user. Especially for sites that are part of advertising communication
campaigns, driven to the relationship between brands and their consumers, which final
objective is to build loyalty and generate the consumption of brands products and services on
the long term. The mapping of users behavior, habits and needs that represent an interface s
target, are basis for the tools and functionalities that the site will offer. A deeper and more
complete mapping drives a more efficient and richer experience for the interface user. Under
this purpose, planning methodologies are used together with user experience design
techniques such as user tests and projective techniques, such as the creation of personas
personas are fictitious characters created to represent the different real users profiles that are
part of the target, defined in demographic, attitudinal and/or behavioral aspects, who will use
a site. Having this context in mind, this study aims to analyze the planning process during
websites creation, with focus on users mapping and understanding, reflecting on the
available methodologies and projective techniques, above all the personas technique, and the
impact of using those techniques in the creative process. Therefore, as methodological basis
for this study we have done documental and bibliographical researches, and a descriptive
presentation of a real case study, for illustrating digital interfaces creative process. The
corpus of this study is the planning process for the creation of the new Brazilian Nestlé s
website. Analysis period: August/2010 to June/2013. There were used as theoretical
foundation concepts of mass communication, culture and consumption, advertising
communication and hybrid advertising from Martin-Barbero, Bauman, Fontenelle, Wolf,
Pinheiro, Carrascoza, Covaleski; of cyberspace and network creation processes from Castells,
Lévy, Manovich, Morin, Deleuze and Guattari, Santaella, Leão, Salles, Lemos; and concepts
of information architecture andu ser experience design from Kruger, Cooper, Moggridge,
Mulder, Adlin. This study may contribute for the development of planning process typology
for the creation of users centered websites, resulting on the development of interfaces
capable to deliver an intuitive, interactive and efficient experience to different types of users
No campo da comunicação, especificamente nos estudos sobre os processos de criação de
interfaces para sites, as áreas de planejamento estratégico e arquitetura de informação/user
experience design são responsáveis pela idealização do conceito e estratégia para a criação e
desenvolvimento da interface digital. Durante o processo criativo, um dos fatores de maior
relevância é o foco no usuário. Sobretudo para sites que pertencem à comunicação publicitária
voltada para o relacionamento das marcas com seus consumidores, cujo objetivo final é
fidelizar consumidores e gerar consumo dos produtos e serviços da marca no longo prazo. A
partir do mapeamento de comportamento, hábitos e necessidades dos usuários que
representam o público-alvo de tal interface, são criadas as ferramentas e funcionalidades que
o site oferecerá. Quanto mais profunda e completa for essa etapa de mapeamento, mais rica e
efetiva será a experiência proporcionada ao usuário pela interface. Para isso, utilizam-se
metodologias de planejamento aliadas a técnicas de desenho da experiência do usuário
(conhecida como user experience design) com testes com usuários e técnicas projetivas,
dentre as quais, destaca-se a de criação de personas personas são personagens fictícios
criados para representar os diferentes tipos de usuários reais, que compõem determinado
público-alvo definido em seus aspectos demográficos, de atitudes e/ou comportamento, que
deverão utilizar um site. Nesse contexto, o presente estudo possui o objetivo de analisar o
processo de planejamento durante a criação de sites, com foco no mapeamento e
entendimento dos usuários, refletindo sobre as metodologias e técnicas projetivas existentes,
sobretudo a técnica de criação de personas, e sobre qual o impacto da utilização dessas
técnicas no processo criativo. Para tanto, como base metodológica desse estudo, foram
realizadas pesquisas documentais, bibliográficas e apresentação descritiva de um estudo de
caso real de mercado, a fim de ilustrar um processo criativo de interfaces digitais. O corpus do
presente estudo é o processo de planejamento para a criação o novo portal brasileiro da marca
Nestlé na internet. Período de análise: Agosto/2010 a Junho/2013. Foram utilizados como
parte da fundamentação teórica conceitos de comunicação, cultura e consumo, comunicação
publicitária e publicidade híbrida de Martin-Barbero, Bauman, Fontenelle, Wolf, Pinheiro,
Carrascoza, Covaleski; de ciberespaço e processos de criação em rede de Castells, Lévy,
Manovich, Morin, Deleuze e Guattari, Santaella, Leão, Salles; e conceitos de arquitetura de
informação e user experience design de Kruger, Cooper, Moggridge, Mulder, Adlin. Esperase
que este estudo contribua para o desenvolvimento de uma tipologia de processo de
planejamento para criação de sites com foco nos usuários, resultando no desenvolvimento de
interfaces que proporcionem aos diferentes tipos de usuários uma experiência intuitiva,
interativa e eficiente
Piaget＇s theory of psychological development can contribute to a better understanding of ADHD （attention deficit hyperactivity disorder）. The assumption is that children with ADHD present deficits in ...the development of the construction of operational notions, such as space-time conceptions and causality. Sixty-nine children （aged 6 to 12） were divided into two groups： children with ADHD and children without diagnosis. According to Piaget＇s clinical interview, Piagetian tasks were applied. The clinical sample was sub-divided into children who used methylphenidate and non-medicated children. ADHD children showed a tendency to response and reasoning considered most common at developmental levels inferior to the comparison group. Regarding the use of methylphenidate, there was no significant difference of performance between the subgroups. Results may be indicative that the deficits relate mainly to structuring aspects of thinking, and not to performance. Theoretical and practical implications were discussed.
Paclitaxel is a chemotherapeutic agent used to treat solid tumours. However, it causes an acute and neuropathic pain syndrome that limits its use. Among the mechanisms involved in neuropathic pain ...caused by paclitaxel is activation of kinin receptors. Angiotensin converting enzyme (ACE) inhibitors can enhance kinin receptor signalling. The goal of this study was to evaluate the role of kinins on paclitaxel-associated acute pain syndromes (P-APS) and the effect of ACE inhibition on P-APS and paclitaxel-associated chronic peripheral neuropathy (P-CPN) in mice. Herein, we show that paclitaxel caused mechanical allodynia and spontaneous nociceptive behaviour that was reduced by antagonists of kinin receptors B
1
(DALBk and SSR240612) and B
2
(Hoe140 and FR173657). Moreover, enalapril (an ACE inhibitor) enhanced the mechanical allodynia induced by a low dose of paclitaxel. Likewise, paclitaxel injection inhibited ACE activity and increased the expressions of B
1
and B
2
receptors and bradykinin-related peptides levels in peripheral tissue. Together, our data support the involvement of kinin receptors in the P-APS and suggest kinin receptor antagonists to treat this syndrome. Because hypertension is the most frequent comorbidity affecting cancer patients, treatment of hypertension with ACE inhibitors in patients undergoing paclitaxel chemotherapy should be reviewed, since this could enhance the P-APS and P-CPN.
