Publication Date:
2008-05-10
Description:
Despite two centuries of effort in characterizing environmental gradients of species richness in search of universal patterns, surprisingly few of these patterns have been widely acknowledged. Species richness along altitudinal gradients was previously assumed to increase universally from cool highlands to warm lowlands, mirroring the latitudinal increase in species richness from cool to warm latitudes. However, since the more recent general acceptance of altitudinal gradients as model templates for testing hypotheses behind large-scale patterns of diversity, these gradients have been used in support of all the main diversity hypotheses, although little consensus has been achieved. Here we show that when resampling a data set comprising 400,000 records for 3,046 Pyrenean floristic species at different scales of analysis (achieved by varying grain size and the extent of the gradients sampled), the derived species richness pattern changed progressively from hump-shaped to a monotonic pattern as the scale of extent diminished. Scale effects alone gave rise to as many conflicting patterns of species richness as had previously been reported in the literature, and scale effects lent significantly different statistical support to competing diversity hypotheses. Effects of scale on current studies may be affected by human activities, because montane ecosystems and human activities are intimately connected. This interdependence has led to a global reduction in natural lowland habitats, hampering our ability to detect universal patterns and impeding the search for universal diversity gradients to discover the mechanisms determining the distribution of biological diversity on Earth.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Nogues-Bravo, D -- Araujo, M B -- Romdal, T -- Rahbek, C -- England -- Nature. 2008 May 8;453(7192):216-9. doi: 10.1038/nature06812.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biodiversity and Evolutionary Biology, National Museum of Natural Sciences, CSIC, C/ Jose Gutierrez Abascal, 2, 28006 Madrid, Spain. davidnogues@mncn.csic.es〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18464741" target="_blank"〉PubMed〈/a〉
Keywords:
*Altitude
;
*Biodiversity
;
Computer Simulation
;
Costa Rica
;
*Human Activities
;
Models, Biological
;
Software
;
Spain
;
Trees/physiology
;
Tropical Climate
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
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