Do Shapes of Elevational Gradients of Species Richness Depend on the Vertical Range Studied? The Case of the Himalayas

We retrieved shapes of elevational species richness gradients (unimodal, decreasing, increasing) from 64 publications, studying Himalayan elevation patterns. We covered both plants and animals, and tested the hypothesis that unimodal gradients, explicable by the geometric mid-domain effect, prevail in the mountains, whereas decreasing or increasing gradients result from studying only short sections of entire altitudinal ranges. Multivariate canonical correspondence analysis was used to relate gradient shapes to their altitude ranges, geography positions, and taxa studied. Across taxa, most of the Himalayan altitudinal gradient display a unimodal shape, with a peak of diversity situated at ca 2500 m a.s.l. for plants, and 2200 m a.s.l. for animals. The gradient shapes were attributable to three intercorrelated predictors: vertical range, maximum elevation, and mean elevation of the gradients. Studies covering sufficiently broad altitudinal range returned unimodal gradients. Studies from the Earth’s highest mountain range reveal that surveys covering substantial parts of the elevational range of the mountains result in unimodal elevational gradients, whereas declining or increasing species richness gradients result from incomplete elevation range sampling.

Changing pattern of plant species utilization in relation to altitude and their relative prevalence in homegardens of Kumaun Himalaya, India

The aim of the present study was to analyse the species utilization pattern and their relative prevalence in homegardens varying in size and altitude. Four sites were selected along an altitudinal gradient viz., very low (up to 350 m), low (350-700 m), mid (700-1500 m) and high altitudes (above 2000 m) in Kumaun Himalaya, India. At each altitude, homegardens were categorized into three size classes viz., large (above 0.007 ha), medium (0.004-0.006 ha) and small homegardens (up to 0.003 ha). Maximum species richness was recorded in large sized homegarden at all altitudes except mid altitude where maximum species was observed in medium sized homegardens. Across altitudes, maximum plant species (39) was recorded at mid altitude whereas minimum species (24) were present in high altitude homegardens. Amaryllidaceae was the most important family followed by Oxalidaceae across all the altitudes. In case of plant utilization pattern, maximum species were utilized as a medicine (44.23 %) followed by vegetables (26.66 %), fodder (18.1 %), miscellaneous (15.97 %), spices (13.97 %) and fruits (12.34 %). Among the species, <i>A. cepa</i> (1380) and <i>C. annuum</i> (1026) showed most prevalence whereas <i>S. cumini</i> (278) was the least prevalent species. Across the altitudinal gradient, mid altitude showed most (2341, 1330) relative prevalence whereas high altitude showed least (876, 0) relative prevalence for <i>A. cepa</i> and <i>M. indica</i>, respectively. Management practices and conventional activity could show a higher effect on species composition and their utilization pattern to improve food security and conserving plant genetic diversity in altitudes.

Distribution characteristics of endemic and rare plants along the altitudinal gradient in Bat Xat nature reserve in Vietnam

This study aimed to assess the relationship between distribution, altitude and investigation lines of vascular plants in Bat Xat Nature Reserve, Lao Cai province. Based on the collected specimens added 273 species of vascular plants belonging to 48 genera, 18 families, bringing the total number the currently known species are 1245 species of vascular plants belonging to 649 genera, 174 families and under 6 divisions such as. Of these, and there are 211 endemic and rare species consists have been recorded and 22 rare species 17 endemic species and updated scientific name 14 species added checklist to the Nature Reserve. Topographic, vegetation and distribution maps, changes in diversity and a checklist of endemic and rare species are shown.

Interpopulation Plasticity in a Darkling Beetle Life-History along a Whole Oceanic Island Altitudinal Gradient

Insects show remarkable phenotypic plasticity in response to changing environmental conditions. The abiotic factors that determine their phenotypes often vary in time and space, and oceanic islands harbour ideal environments for testing predictions on this matter. The ubiquitous beetle Pimelia laevigata costipennis Wollaston, 1864 (Tenebrionidae) is distributed over the entire altitudinal gradient of the island El Hierro (Canary archipelago), from 0 to 1501 m above sea level. Here, we examine how environmental factors (i.e., rainfall and temperature), associated with the altitudinal gradient, affect the body size, reproductive phenology, clutch size and egg volume, and population dynamics of this ectothermic flightless insect. Pimelia l. costipennis populations inhabiting upland localities, typified by lower temperatures, and greater precipitation and vegetation cover, were larger in body size and laid larger clutches with smaller eggs than those in the lowlands. Moreover, reproduction occurred earlier in the year at lower sites and later at higher sites, whereas activity density was highest in the uplands where it increases with temperature. This study first explores the changes in life history patterns along a whole insular altitudinal gradient, and finds interpopulation plasticity. It confirms that environmental factors associated with species spatial distribution act additively as drivers of phenological and phenotypic expression.

Fish community structure along altitudinal gradients with relation to environmental variables in Ratuwa River of Eastern, Nepal

Studies on fish community structure along altitudinal gradients of rivers are lacking in Nepal. This study was carried out to gauge the fish diversity and composition along elevational gradient in Ratuwa River. The altitudinal gradient varies between 70 m to 1300 m. Fish samples were collected based on habitat representativeness from April (spring) 10-18, July (summer) 10-18, October (autumn) 10-18, 2020 and January (winter) 10-18, 2021. A total of 3447 specimens representing 4 orders, 14 families and 36 species were identified. Both fish diversity and abundance of studied ichthyofauna vary with altitudinal gradient. The present study affirmed that fish species of Opsarius bendelisis, Schistura multifasciatus, Garra annandalei, Brachydanio rerio, Aspidoparia morar, and Schistura scaturigina are the major contributory species (>1%) for both space and time spectrums. Fish community structure testing for both to space and time showed significant difference in spatial spectrum (R=0.72, P<0.01) but no significant difference in temporal variation (R=-0.034, P>0.05). The present results hinted that fish assemblage structure varied significantly from low to high elevations, altitude, water temperature, water velocity, dissolved oxygen and pH was found as major influential factors (P<0.05) for species distribution.