Phytoplankton in the Mitika Wetland, Tibet, China: 1. Spatio-temporal niche of dominant species

The responses of lowland tropical communities to climate change will critically influence global biodiversity but remain poorly understood. If species in these systems are unable to tolerate warming, the communities—currently the most diverse on Earth—may become depauperate (‘biotic attrition’). In response to temperature changes, animals can adjust their distribution in space or their activity in time, but these two components of the niche are seldom considered together. We assessed the spatio-temporal niches of rainforest mammal species in Borneo across gradients in elevation and temperature. Most species are not predicted to experience changes in spatio-temporal niche availability, even under pessimistic warming scenarios. Responses to temperature are not predictable by phylogeny but do appear to be trait-based, being much more variable in smaller-bodied taxa. General circulation models and weather station data suggest unprecedentedly high midday temperatures later in the century; predicted responses to this warming among small-bodied species range from 9% losses to 6% gains in spatio-temporal niche availability, while larger species have close to 0% predicted change. Body mass may therefore be a key ecological trait influencing the identity of climate change winners and losers. Mammal species composition will probably change in some areas as temperatures rise, but full-scale biotic attrition this century appears unlikely.

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Spatio-Temporal Persistence of the Abra Alba-Pectinaria Koreni Muddy-Fine Sand Community of the Eastern Bay of Seine

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315400038698 ◽

1997 ◽

Vol 77 (4) ◽

pp. 1165-1185 ◽

Cited By ~ 43

Author(s):

E. Thiébaut ◽

L. Cabioch ◽

J.-C. Dauvin ◽

C. Retiere ◽

F. Gentil

Keyword(s):

Dominant Species ◽

Salinity Gradient ◽

Food Limitation ◽

Temporal Stability ◽

Fine Sand ◽

Temporal Variations ◽

Total Density ◽

Factorial Correspondence Analysis ◽

Spatio Temporal ◽

Density And Biomass

The spatial distribution and temporal variations of the Abra alba-Pectinaria koreni community from the eastern part of the Bay of Seine were investigated through four winter surveys (1986, 1987, 1988 and 1991). A grid of 40–67 stations was sampled each year using a Hamon grab (0·25 m-2) for macrofauna collection and sediment analysis. The fauna was dominated by polychaetes and in a lower part by molluscs and echinoderms. Although species richness with ~100 species collected during each survey was high, total density and biomass (±SE) resulted principally from about ten dominant species, and varied between 846·9 ±163·5 and 1135·3 ±186·7 ind m-2 and 23·52 ±4·41 and 27·48 ±4·45 g m-2respectively. The dominant species were patchily distributed and exhibited weak spatio-temporal fluctuations except the two bivalves A. alba and Cultellus pellucidus. Factorial correspondence analysis (FCA) of the distribution of main species among stations and automatic hierarchical classification identified five faunal assemblages which were relatively stable in space and time. The temporal stability of the community could be generated by processes of larval retention near parental population, and sediment stabilization induced by the low abundance of deposit feeders and the high densities of the tube-dwelling polychaete Owenia fusiformis. While the sediment variables were a poor indicator of the spatial structure of the community, the salinity gradient off the Seine Estuary and post-settlement processes (e.g. food limitation and postlarval drifting) have been proposed to explain it. Comparison with an earlier survey (i.e. 1971) suggested a degree of long-term persistence of the community structure in qualitative and quantitative terms.

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