Climate vulnerability, impacts and adaptation in Central and South America coastal areas

© 2019 Elsevier B.V. Low-Elevation Coastal Zones in Central and South America are exposed to climate-related hazards (sea-level rise, climate variability and storms) which threaten the assets (people, resources, ecosystems, infrastructure, and the services they provide), and are expected to increase due to climate change. A non-systematic review is presented focusing on vulnerability elements, impacts, constraints to adaptation, and their possible strategies. The analysis emphasises the Intergovernmental Panel on Climate Change Reasons for Concern (e.g., threatened systems, extreme events, aggregated impacts, and critical thresholds), particularly on sea-level rise, degradation of mangroves, and invasive alien species in Central and South America focusing on case studies from Uruguay and Venezuela. Despite recent advances in coastal adaptation planning in Central and South America, there is an adaptation deficit in the implementation of measures and strategies against climate-related hazards, such as sea-level rise. Adaptation constraints are linked with poverty, resource allocation, lack of political will, and lack of early warning systems for climate-related hazards. Non-structural adaptation measures such as community-based adaptation and ecosystem-based adaptation are not fully mainstreamed into national plans yet. Government-level initiatives (e.g. National Adaptation Programmes of Action) are being developed, but a few are already implemented. In addition to specific thematic measures, the implementation of non-structural approaches, National Adaptation Programmes of Action and early warning systems, based on the reasons for concern, should foster adaptive capacity in coastal areas

Wind effect as forcing factor controlling distribution and diversity of copepods in a shallow temperate estuary (Solis Grande, Uruguay)

Spatial and temporal variations of planktonic copepods were investigated in relation to environmental conditions in the Solís Grande estuary (34°22´S, 55°33´W), Uruguay. Over a period of fifteen days, samples were taken daily at three stations along the main axis of the estuary, and the species composition and abundance were determined. The Solís Grande is a shallow estuary (2.0 m) with no vertical discontinuities. Comparisons of surface versus bottom hydrographic values indicated no vertical stratification of temperature and salinity during the studied period. The species-environmental relationships explain 63.6% of the system´s variability considering the two first axes from Redundance Analysis (RA). Copepods showed strong differences in distribution and abundance between stations and successive days. In the region the winds quickly rotate from sectors S-SE (frontal period) to E-NE (post-frontal period). Changes in abundance were significantly related to the inflow and outflow of water produced by the rotation of winds. At smaller space and time scales, the differences highlighted by the RA were the result of wind-forced hydrodynamics after the frontal period. In this situation hydrographic features were dominant (factor one of RA) and wind effects were of secondary importance (factor two of RA). Six species were identified and the estuary was clearly dominated by Acartia tonsa. The results showed two negatively correlated groups: one was integrated by Oithona nana, O. simplex, Paracalanus parvus and P. crassirostris while the second group was integrated by A. tonsa and Euterpina acutifrons. Environmental variability may be responsible for the low diversity.No disponibl

Modeling the Suspended Sediment Transport in a Very Wide, Shallow, and Microtidal Estuary, the Río de la Plata, Argentina

The impact of the diverse processes responsible for the distribution of suspended sediments in the wide, shallow, and microtidal Río de la Plata estuary and the adjacent shelf is studied by means of a set of process-oriented numerical simulations. Model results show that the large width and the geometry of the estuary play a major role in the sedimentation processes. The widening and deepening of the estuary drives a significant reduction in current speeds at (i) the confluence of the tributaries and (ii) downstream Barra del Indio Shoal. Thus, sediment deposition enhances downstream those areas. Even though tides are of small amplitude in the study area, they have a significant impact on lateral mixing and resuspension of the bottom sediments. Resuspension augments the concentration of fine sediments in the layers close to the bottom, but tidal energy is not enough to lift them to the surface. Winds (which can be quite strong over this area) enhance horizontal mixing, smoothing the pattern produced by tides. Wind waves increase the concentration of sediment by vertical mixing, and their effect is most evident along the southern coast where wind waves lift the sediments resuspended by tides to the surface. The estuarine circulations associated to the bottom salinity front acts retaining sediments upstream the Barra del Indio Shoal, where estuarine currents and flocculation play an important role in sediment deposition.Fil: Moreira, Diego. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones del Mar y la Atmósfera. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones del Mar y la Atmósfera; Argentina. Instituto Franco-argentino sobre Estudios del Clima y sus Impactos; ArgentinaFil: Simionato, Claudia Gloria. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones del Mar y la Atmósfera. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones del Mar y la Atmósfera; Argentina. Instituto Franco-argentino sobre Estudios del Clima y sus Impactos; Argentin

Fish assemblage in a temperate estuary on the uruguayan coast: seasonal variation and environmental influence

The seasonal dynamics of the fish community in the Pando estuary on the Uruguayan coast were studied in relation to environmental sampled monthly between May 2002 and June 2003. Individuals collected were identified, and classified into stages (juveniles, adults) and functional groups. Relationships between community dynamics and environmental variables were evaluated using uni- and multivariate techniques. Twenty-one species, mostly freshwater stragglers, estuarine and marine migrants were collected. The most abundant species were Micropogonias furnieri, Mugil platanus, Paralichthys orbignyanus and Brevoortia aurea and were represented by juveniles. The community varied seasonally with rapid shifts in spring and autumn associated with changes in temperature and salinity. Significant correlations between abundance and temperature may be related to the timing of life cycle events. In this estuary, the salinity appears to play a key role in the functional structure and in the use of the habitat by juveniles. This is relevant for the definition of estuaries as nursery areas: this definition is context-dependent and is determined by the salinity conditions.<br>Foi estudado a dinâmica sazonal da comunidade de peixes em relação as variáveis ambientais do estuário Pando, localizado na costa uruguaia. Os peixes foram amostrados mensalmente entre maio de 2002 e junho de 2003. Os indivíduos coletados foram identificados e classificados em estágios (jovens, adultos) e grupos funcionais. Relações entre a dinâmica da comunidade e as variáveis ambientais foram avaliadas utilizando-se técnicas uni- e multivariada. Vinte e uma espécies foram coletadas, principalmente visitantes de água doce, estuarinas e marinhas migratórias, sendo as mais abundantes e representadas por juvenis: Micropogonias furnieri, Mugil platanus, Paralichthys orbignyanus e Brevoortia aurea. A comunidade variou sazonalmente com rápidas mudanças na primavera e no outono, associadas à variações de temperatura e salinidade. Correlações significativas entre abundância e temperatura parecem estar relacionadas com a sincronizaçao de eventos dos ciclos de vida. Neste estuário a salinidade parece desempenhar um papel-chave na estrutura funcional e uso do habitat por juvenis. Este fato é relevante para a definição dos estuários como áreas de criadouro e pela influencia da salinidade sobre o ciclo da ictiofauna local