156 research outputs found
Modeling approach to regime shifts of primary production in shallow coastal ecosystems
Pristine coastal shallow systems are usually dominated by extensive meadows
of seagrass species, which are assumed to take advantage of nutrient supply
from sediment. An increasing nutrient input is thought to favour phytoplankton,
epiphytic microalgae, as well as opportunistic ephemeral macroalgae that
coexist with seagrasses. The primary cause of shifts and succession in the
macrophyte community is the increase of nutrient load to water; however
temperature plays also an important role. A competition model between rooted
seagrass (Zostera marina), macroalgae (Ulva sp), and phytoplankton has been
developed to analyse the succession of primary producer communities in these
systems. Successions of dominance states, with different resilience
characteristics, are found when modifying the input of nutrients and the
seasonal temperature and light intensity forcing.Comment: 33 pages, including 10 figures. To appear in Ecological Complexit
Assessment of ecosystem services of an urbanized tropical estuary with a focus on habitats and scenarios
Tropical estuaries are one of the most valuable ecosystems on the planet because of the number of ecosystem services they provide. The increasing anthropogenic pressure to which these estuaries are subject has caused a reduction in their natural capital stock. Therefore, the application of a pragmatic and rational ecosystem-based management approach to sustainably manage the multiple ecosystem services provided by this ecosystem is necessary. The aim of our study is to present an approach that combines prospective scenarios with habitat-based perspective to assess the supply capacity of ecosystem services, plus determine the impact of protected areas in an urbanized tropical estuary. The current situation and two scenarios were generated to evaluate the capacity of habitats to supply ecosystem services. This type of assessment will allow the decision makers to visualize the effect of their choices or the occurrence of events which might produce significant changes in the estuary. Thus, over time, measures can be taken to sustain the supply of ecosystem services. We determined that the establishment of protected areas have a positive impact; however, the effect is not the same for all of them. Consequently, indicating that actions such as community participation, research, education, management planning and infrastructure development must accompany the development of a protected area
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