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Numerology Chaldean Numerology The numerical value of species richness in Chaldean Numerology is: 1 Pythagorean Numerology The numerical value of species richness in Pythagorean Numerology is: 9. Select another language:. Please enter your email address: Subscribe. Discuss these species richness definitions with the community: 0 Comments.
Notify me of new comments via email. Cancel Report. Create a new account. Log In. Powered by CITE. Are we missing a good definition for species richness? Don't keep it to yourself Submit Definition. What is a species? Do any frogs live in salty waters? What do swamp eels eat? Is it better to have phenotypic or genotypic references when identifying an unknown species?
How do adaptations affect a species? What is an example of mutualism? The morphologically complex thallus of this alga Dudgeon and Johnson might attract a number of small species that would otherwise be absent, resulting in total richness peaking at middle elevations, as the ESM predicted Fig. Our richness data did not show such a peak, but species size may have influenced this outcome.
Because of constraints in logistics and taxonomic expertise, we restricted observations to organisms larger than 1 mm. Thus, if very small species were in fact drawn to middle elevations by M. This type of limitation is a universal problem affecting intertidal diversity studies Kimbro and Grosholz ; Russell et al.
In fact, we know of no community study, aquatic or terrestrial, that has not suffered from this drawback. Increased efforts to identify even the smallest species might thus improve the accuracy of trend determination in ESM research.
The above discussion must not be taken, however, as an indication that ESM-predicted patterns in richness did occur in Helgoland but our surveys failed to detect them. For example, at Bunker, the combined cover of all morphologically complex algae M. Then, were these algae promoting a high occurrence of very small species there, total richness would still not follow a unimodal pattern.
Another prediction of the ESM on interspecific interactions is that consumers should play larger roles as stress decreases Bruno et al. Is there evidence in our data suggesting that consumer pressure may have been particularly strong at low elevations? Percent cover data as well as other abundance measures, such as density and biomass may not be accurate indicators of consumer pressure, but offer information for a basic analysis.
On Helgoland rocky shores, periwinkles Littorina spp. The most abundant periwinkles, Littorina littorea and L. Janke and on the brown algae Fucus spp. Watson and Norton , respectively, while the mussel Mytilus edulis is a preferred food item for C. From middle to low elevations on our studied shores, the abundance of these consumers generally remained similar or decreased Table 1.
In the only case in which it clearly increased L. These observations suggest that consumer pressure may not be particularly strong at the low intertidal zone relative to higher elevations. Field experiments should be done to confirm this notion, which may also contribute to explaining why overall richness and diversity did not decrease from middle to low elevations, as the ESM had predicted.
An alternative possible explanation for ESM-predicted patterns in richness and diversity not occurring in Helgoland relates to the extent of the intertidal range.
For example, the change from stress being the main factor structuring communities, to species coexistence and higher richness of basal species, to competitive exclusions among basal species, to predation disrupting such exclusions occurs from high elevations down the intertidal zone on the Pacific coast of North America Paine ; Kim ; Robles et al.
On shores with smaller tidal ranges e. We suggest that ESM-predicted patterns might become increasingly evident with increasing intertidal range. A possible solution to working on shores with a limited intertidal range might be to increase the spatial resolution of sampling.
For example, on each Helgoland shore, we sampled the full intertidal range between chart datum and the upper intertidal boundary. However, we combined data for quadrats from the lower, middle, and upper thirds of the range to describe average richness and diversity for the low, middle, and high intertidal zones.
This is a common approach in intertidal ecology, allowing researchers to identify broad patterns Menge and Branch ; Konar et al. Thus, if full ESM-predicted patterns did occur on a shore with a limited intertidal range, sampling at a higher resolution might reveal them. This approach would require sampling almost 3 times more quadrats than a classic 3-zone study to maintain the same sampling effort at each zone. Nonetheless, future ESM tests might profit from following this approach.
A final consideration is due regarding the trends followed by richness and diversity in Helgoland. Both traits showed the same pattern across elevation at Kringel, but differences existed at Nord-Ost Hafen and Bunker.
A similar situation occurred across the shores, as richness was lower at Kringel than on the other 2 shores, but diversity was similar in Kringel and Bunker. Logically, these differences were explained by evenness trends Krebs Richness and diversity have been considered virtually as synonyms in many biodiversity studies Whittaker et al. Since both richness and diversity help to understand community functioning, predicting how they vary with stress is thus important.
Therefore, future ESM studies should quantify richness, diversity, and evenness simultaneously to facilitate ecological synthesis. Estuar Coast Shelf Sci — Article Google Scholar. Rev Chil Hist Nat — J Exp Mar Biol Ecol — Bertness MD Atlantic shorelines. Natural history and ecology. Princeton University Press, Princeton. Google Scholar. Ecology — Ecol Monogr — Trends Ecol Evol — Chiba S Species richness patterns along environmental gradients in island land molluscan fauna.
PubMed Article Google Scholar. Crain CM, Bertness MD Ecosystem engineering across environmental gradients: implications for conservation and management. Bioscience — Eschweiler N, Molis M, Buschbaum C Habitat-specific size structure variations in periwinkle populations Littorina littorea caused by biotic factors. Helgol Mar Res — Gamfeldt L, Hillebrand H Biodiversity effects on aquatic ecosystem functioning—Maturation of a new paradigm.
Internat Rev Hydrobiol — Am Nat E23—E Harley CDG, Helmuth BST Local- and regional-scale effects of wave exposure, thermal stress, and absolute versus effective shore level on patterns of intertidal zonation. Limnol Oceanogr — Oxford University Press, New York. Mar Ecol Prog Ser —
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