Nekton Biodiversity And Mangrove Food Webs

Nekton (free-swimming organisms) food webs represent faunal guilds that utilize mangrove habitats for food and protection at different stages of their life cycle. Most of these organisms are migratory (while there may be some residents), and the ephemeral nature of the periods when these organisms utilize mangrove habitats contributes to the poor understanding of their ecology. Robertson and Blaber (1992) reviewed the results of four mangrove fish community studies in northern Australia where...

Stability And Species Richness

Discussions of the degree and causes of stability are frequently hampered by vagueness and inconsistency about what is meant by stability (Orians 1975). Stability may simply mean constancy, that is a low level of variation in some measurable property of the system. Stability may also refer to the resistance of the system to alteration by external perturbations (inertia), its speed of return to initial conditions following a perturbation (elasticity or resilience), the domain over which it...

Freshwater Ecosystems Linkages of Complexity and Processes

PERSSON, M. POWER AND D. SOTO 12.1 INTRODUCTION 12.1.1 Uses of Freshwaters Freshwater ecosystems are indispensable for life. Unlike some resources, there is no substitute for water. Its availability influences the distribution of Earth's major biomcs and the productivity of agriculture. Historically, fresh-waters have been a magnet for human settlement. Important human uses of freshwaters include drinking, fishing, industry, irrigation, recreation and transportation...

Conclusion biodiversity and ecosystem function from genes to regions

To conclude, we have identified how biodiversity, from genes to regions, may alfect ecosystem function in coral reefs. At a single reef, diversity in the life-history characteristics of reef biota, both within and among species, provides the basis for occupancy and survival in the broad range of environments that the reef provides. The diversity of a reefs zones is essential to the maintenance and accretion of the overall structure itself, and of its protein resources. Each zone's...

Mangrove Faunal Guilds And Ecosystem Function

Animal species co-occurring in mangrove forests can be separated into guilds characterized by the utilization of available resources (Ray and McCormick 1992). Fauna) guilds described in this section are basically resident species that exploit the habitat with different intensity in space and time, in contrast to the nekton guilds discussed below (Section 13.6). The utilization and exploitation of the mangrove habitat by faunal guilds, both resident and migratory, can contribute to the structure...

Info

Mean level of channel water al low tide Figure 13.6 Vertical zonation and abundance of epibenthos on Rhizophora apiculata trees, Phuket Island (Taken from Alongi and Sasekumar 1992 as modified from Frith et al. 1976). Species codes 1, Sea anemone sp.A 2, Sea anemone sp.B 3, Nemertine sp.A 4, Lepidonotus kumari 5, Betroiisthes sp. 6, Cibanarius padavensix 7, Diogenes avarus 8. Leipocten sordidulum 9, Tylodiplax tetra-tylophora 10, Batanas amphitrite 11, Chthamalus withersii 12, Ligia sp. 13,...

Facilitators as links between humans biodiversity and ecosystem function

Three case studies illustrate reef turn-off caused by population fluctuations in echinoderm facilitator species. In the first, the turn-off appears to be rapidly reversible without human intervention in human time scales in the latter two, the situation appears to be irreversible, or at least much slower than expected. Crown-of-thorns starfish. In the 1960s and 1980s, populations of the crown-of-thorns starfish Acanthaster planci, for reasons unknown, increased by several orders of magnitude...

Water quality and land runoff effects on biodiversity and ecosystem function

The water flowing onto a coral reef acts as a transport medium for materials (organic matter, nutrients, sediments, propagules - sec Section 15.3) which are beneficial when delivered at appropriate concentrations and frequencies, but may be deleterious when delivered in excess. Mechanisms for nutrient impacts on coral reefs Four mechanisms for nutrient impact on reefs are rccognised, although cause and effect have been difficult to establish unequivocally (Bell 1992). Should they reach a reef...

Effect Of Species Diversity On Ecosystem Function

We now explore how changes in species diversity affect ecosystem function in order to test our null hypothesis. For this purpose we make use of natural and unplanned human experiments involving the addition and or removal of plant and animal species from natural savanna ecosystems. 8.4.1 Invasion of South American and Australian savannas by African Several species of African grasses (such as Hypharrenia rufa, Melinis minuli-flora and Panicum maximum) have becomc naturalized in the South...

Savanna Structure And Function

Litterfall And Decomposition Plant

Ecosystem function can be interpreted in two ways. It can refer to the flow of energy and nutrients through an ecosystem or to the flow of species populations through time, i.e. the persistence of species populations and their properties, what Holling calls the resilience of the system (Holling 1973, 1986 Solbrig 1993). The usual way of looking at ecosystem function is to consider only the flow of energy and nutrients. We first discuss how species characteristics control the flow of energy and...

Tropical forests

The lime dimension Tropica forests illustrate the importance of the time dimension in considering the roles of species in ecosystem functioning. Through selective harvesting of plants and animals we have performed many experiments' to test the role of various species and functional groups in the functioning of total ecosystems. However, interpreting the results of these experiments may take a long time, since many organisms live for centuries and many ecosystem processes have very long time...

References

Adis, J.Y., Lubin, Y.D. and Montgomery, G.C. (1984) Arthropods from the canopy of inundated and terra iirme forests near Manaus, Brazil, with critical considerations on the pyrethrum-fogging technique. Stud. Neotrop. Fauna Environ. 19 223-236. Altieri, M.A. (1990) Why study traditional agriculture In Caroll, C.R., Vandermeer, J.H. and Rosset, P.M. (Eds) Agroecology. McGraw-Hill, New York, pp. 551-546. Altieri, M.A., Cure, J.R. and Garcia, M.A. (1993) The role and enhancement of parasitic...