Variability of size structure and species composition in Caribbean octocoral communities under contrasting environmental conditions

2018 ◽  
Vol 165 (2) ◽  
Author(s):  
Georgios Tsounis ◽  
Peter J. Edmunds ◽  
Lorenzo Bramanti ◽  
Bonnie Gambrel ◽  
Howard R. Lasker
Keyword(s):  
Species Composition ◽  
Environmental Conditions ◽  
Size Structure

scholarly journals Environmental and ecological factors mediate taxonomic composition and body size of polyplacophoran assemblages along the Peruvian Province

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Christian M. Ibáñez ◽  
Melany Waldisperg ◽  
Felipe I. Torres ◽  
Sergio A. Carrasco ◽  
Javier Sellanes ◽  
...  
Keyword(s):  
Body Size ◽  
Species Composition ◽  
Size Structure ◽  
Environmental Gradients ◽  
Ecological Factors ◽  
Taxonomic Composition ◽  
Latitudinal Gradients ◽  
Size Segregation ◽  
Biogeographic Patterns ◽  
Diversity Gradient

Abstract Intertidal communities’ composition and diversity usually exhibit strong changes in relation to environmental gradients at different biogeographical scales. This study represents the first comprehensive diversity and composition description of polyplacophoran assemblages along the Peruvian Province (SE Pacific, 12°S–39°S), as a model system for ecological latitudinal gradients. A total of 4,775 chitons from 21 species were collected on twelve localities along the Peruvian Province. This sampling allowed us to quantitatively estimate the relative abundance of the species in this assemblage, and to test whether chitons conform to elementary predictions of major biogeographic patterns such as a latitudinal diversity gradient. We found that the species composition supported the division of the province into three ecoregional faunal groups (i.e. Humboldtian, Central Chile, and Araucanian). Though chiton diversity did not follow a clear latitudinal gradient, changes in species composition were dominated by smaller scale variability in salinity and temperature. Body size significantly differed by ecoregions and species, indicating latitudinal size-structure assamblages. In some localities body size ratios differed from a random assemblage, evidencing competition at local scale. Changes in composition between ecoregions influence body size structure, and their overlapping produce vertical size segregation, suggesting that competition coupled with environmental conditions structure these assemblages.

scholarly journals The results of the introduction of Juglans mandshurica Maxim. into the oak-woods of the Khopyor region

2018 ◽  
Vol 11 ◽  
pp. 00030
Author(s):  
Anastasia Ovcharenko ◽  
Alevtina Ovcharenko
Keyword(s):  
Species Composition ◽  
Environmental Conditions ◽  
Flood Plain ◽  
Distribution Area ◽  
Juglans Mandshurica ◽  
Ecological Functions ◽  
Natural Distribution ◽  
The Stability ◽  
Selection Of Species ◽  
Selection Of

An analysis of the results of the introduction of Juglans mandshurica Maxim. into the flood-plain oak-woods of the Khopyor is conducted. The total bioecological assessment and prospects of the introduction into the natural flood-plain oak-woods of the Middle Khopyor region for the enrichment of their species composition with the aim of enhancing the sustainability of these ecosystems and optimization of their ecological functions are given. The compliance of the environmental conditions of the growth of introduced stands in the middle reaches of the Khopyor River, original within the natural distribution area is found. Alongside with the identified typical directions of reduction in the indicators of the stability and productivity of this breed in introduced centres in comparison with the natural areas there detected trends in increasing the resistance of the species in the succeeding generations, as a result of clone variability, a selection of species with a high vital potential and adaptive capacity.

Advance regeneration and trajectories of stand development following the mountain pine beetle outbreak in boreal forests of British Columbia

2015 ◽  
Vol 45 (10) ◽  
pp. 1327-1337 ◽  
Author(s):  
Elizabeth M. Campbell ◽  
Joseph A. Antos
Keyword(s):  
British Columbia ◽  
Species Composition ◽  
Boreal Forests ◽  
Mountain Pine Beetle ◽  
Size Structure ◽  
Fire Disturbance ◽  
Active Management ◽  
Advance Regeneration ◽  
Mountain Pine ◽  
Pine Beetle

A mountain pine beetle (Dendroctonus ponderosae Hopkins) outbreak has recently spread into boreal forests, with unknown consequences for this ecosystem. We intensively sampled 12 stands affected by the current outbreak in northern British Columbia to determine the potential of western boreal forests to recover from this novel disturbance. We sampled the species composition, size structure, and spatial distribution (using 5 m × 5 m subplots, 40 per stand) of live and dead trees and used a variety of analyses, including ordinations, to assess potential developmental trajectories of stands. Advance regeneration (stems < 10 m tall) varied greatly in abundance among stands (50–18 280 stems·ha−1). However, most subplots contained at least one individual; only three stands had many empty subplots. We conclude that most stands have enough advance regeneration and residual canopy trees to form a nearly continuous new canopy. Ordinations indicate that species composition will shift substantially and become more divergent among stands. Species of high economic value will remain common, though, and active management will not be necessary in most stands to maintain productive forests. However, this novel disturbance will have very different effects on these forests than the typical fire-disturbance regime and is likely to deflect these forests into new successional trajectories.

scholarly journals Periphytic Diatoms in the Polluted Linggi (sensu stricto) and Kundor Rivers, Negeri Sembilan, Malaysia

2017 ◽  
Vol 32 (1) ◽  
pp. 60 ◽  
Author(s):  
I.S.A. NATHER KHAN
Keyword(s):  
Species Composition ◽  
Environmental Conditions ◽  
Abundant Species ◽  
Sensu Stricto ◽  
Diatom Assemblage ◽  
Artificial Substrates ◽  
Nitzschia Palea ◽  
Periphytic Diatoms ◽  
Species Composition And Distribution ◽  
Periphytic Diatom

The investigation in this paper aimed to describe periphytic diatom assemblage, species composition and distribution in tropical polluted Linggi (sensu stricto or s.s.) and Kundor rivers in  Negeri Sembilan, Malaysia.  Regardless of ecological and environmental conditions, diatoms were the numerically dominant flora among periphytic  algae  collected monthly over a period of 13 months at nine stations in the Linggi (s.s.) and Kundor rivers.  The freshwater periphytic diatom samples were collected mainly using artificial substrates and supplemented with natural substrates.  The periphytic diatoms thus collected from both natural and artificial substrates comprised 86 taxa (82 pennate and 4 centric forms) belonging to 21 genera. Of the 86 species, 71 species were found colonized in artificial substrates while the remaining 15 species were recorded exclusively on natural substrates. On the whole, the most common diatoms in both rivers combined were Eunotia vanheurckii, Gomphonema parvulum, Nitzschia palea, Pinnularia braunii, Navicula cryptocephala, Achnanthes saxonica, Achnanthes minutissima and Pinnularia microstauron.  The most abundant species were E. vanheurckii, N. palea, A. saxonica, G. parvulum and A. minutissima.

scholarly journals KOMPOSISI JENIS DAN FUNGSI PEKARANGAN (Studi kasus desa Giripurwo, Kecamatan Girimulyo, DI Yogyakarta)

2017 ◽  
Vol 4 (1) ◽  
pp. 77
Author(s):  
Junaidah Junaidah ◽  
P.Suryanto P.Suryanto ◽  
Budiadi Budiadi
Keyword(s):  
Species Composition ◽  
Environmental Conditions ◽  
Woody Plants ◽  
Timber Trade

Homegarden is one form of agroforestry complex which has a diverse structure and species composition. This research is aimed to (1) Determine the composition on 3 (three) levels development of homegarden, (2) Determine the function of crops on 3 (three) levels development of homegarden.  The sample location was done purposively based on the availability of data and information obtained in the field.  The number of homegarden which will be observed is 12 piece who representing 3 (three) levels development of homegarden, namely early homegarden, intermediate homegarden and advanced homegarden. Observations and measurements of vegetation used census (100%) on the entire plot. The results showed each level  development of homegarden have different  structure and composition of species. More advanced the level development of  homegarden, the number of woody plants increased while the number of crops decreased. This condition causes changes in the environmental conditions at under the stand. The function of homegardenat Giripurwo village is as a source of food, timber, trade commodities, spices, medicine, social, craft materials and ornamental plants.Pekarangan salah satu bentuk agroforestri komplek dimana memiliki struktur dan komposisi jenis yang sangat beragam. Penelitian ini bertujuan untuk (1) Mengetahui komposisi jenis pekarangan pada berbagai tingkat perkembangan, (2) Mengetahui  fungsi pekarangan pada berbagai tingkat perkembangan. Penentuan sampel lokasi penelitian dilakukan secara purposive berdasarkan ketersediaan data dan informasi yang diperoleh di lapangan. Pekarangan yang diamati berjumlah 12 buah yang mewakili 3 tingkat perkembangan pekarangan, yaitu: pekarangan awal, pekarangan menengah dan pekarangan lanjut. Pengamatan dan pengukuran vegetasi secara sensus (100 %) pada seluruh plot ukur. Hasil penelitian menunjukkan struktur dan komposisi pada tiap tingkat perkembangan pekarangan berbeda. Semakin lanjut tingkat perkembangan pekarangan, jumlah jenis tanaman berkayu meningkat sedangkan   jumlah  jenis tanaman semusim menurun. Kondisi ini menyebabkan perubahan kondisi lingkungan di bawah tegakan. Fungsi pekarangan bagi masyarakat Dusun Bulu, Desa Giripurwo adalah sebagai sumber pangan, penghasil kayu, komoditi perdagangan, rempah-rempah, obat-batan, sosial, bahan baku kerajinan dan tanaman hias.

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