Impoverishment in the Bird Community of a Finnish Archipelago: The Role of Island Size, Isolation and Vegetation Structure

1989 ◽  
Vol 16 (2) ◽  
pp. 159 ◽  
Author(s):  
Jean-Louis Martin ◽  
Jacques Lepart
Keyword(s):  
Vegetation Structure ◽  
Bird Community ◽  
Island Size

Disentangling the role of management, vegetation structure, and plant quality for Orthoptera in lowland meadows

2017 ◽  
Vol 26 (2) ◽  
pp. 366-378 ◽  
Author(s):  
Jens Schirmel ◽  
Rebekka Gerlach ◽  
Constanze Buhk
Keyword(s):  
Vegetation Structure ◽  
Plant Quality

scholarly journals Deep and wide valleys drive nested phylogeographic patterns across a montane bird community

2015 ◽  
Vol 282 (1810) ◽  
pp. 20150861 ◽  
Author(s):  
V. V. Robin ◽  
C. K. Vishnudas ◽  
Pooja Gupta ◽  
Uma Ramakrishnan
Keyword(s):  
Bird Community ◽  
Mountain Range ◽  
Climatic Fluctuations ◽  
Tropical Mountain ◽  
Palghat Gap ◽  
Spatial Concordance ◽  
Species Evolution ◽  
The Western Ghats ◽  
Range Fragmentation

Montane species distributions interrupted by valleys can lead to range fragmentation, differentiation and ultimately speciation. Paleoclimatic fluctuations may accentuate or reduce such diversification by temporally altering the extent of montane habitat and may affect species differentially. We examined how an entire montane bird community of the Western Ghats—a linear, coastal tropical mountain range—responds to topographic valleys that host different habitats. Using genetic data from 23 species (356 individuals) collected across nine locations, we examined if different species in the community reveal spatial concordance in population differentiation, and whether the timing of these divergences correlate with climatic events. Our results reveal a nested effect of valleys, with several species (10 of 23) demonstrating the oldest divergences associated with the widest and deepest valley in the mountain range, the Palghat Gap. Further, a subset of these 10 species revealed younger divergences across shallower, narrower valleys. We recovered discordant divergence times for all valley-affected montane birds, mostly in the Pleistocene, supporting the Pliestocene-pump hypotheses and highlighting the role of climatic fluctuations during this period in driving species evolution. A majority of species remain unaffected by valleys, perhaps owing to geneflow or extinction–recolonization dynamics. Studying almost the entire community allowed us to uncover a range of species’ responses, including some generalizable and other unpredicted patterns.

Impact of fire on vegetation, soil microbes and CH4 emission from a degraded tropical peatland

2020 ◽  
Author(s):  
Hasan Akhtar ◽  
Massimo Lupascu ◽  
Omkar S. Kulkarni ◽  
Aditya Bandla ◽  
Rahayu S. Sukri ◽  
...  
Keyword(s):  
Southeast Asia ◽  
Water Table ◽  
Vegetation Structure ◽  
High Throughput Sequencing ◽  
Microbial Community Composition ◽  
Tropical Peatland ◽  
Tropical Peatlands ◽  
Peat Profile ◽  
The Impact

<p>Over the past few decades, tropical peatlands in Southeast Asia have been heavily degraded for multiple land uses, mainly by employing drainage and fire. More importantly, the extent of these degraded areas, primarily covered with ferns and sedges, have increased to almost 10% of the total peatland area in Southeast Asia. In particular, the role of sedges in plant-mediated gas transport to the atmosphere has been recognized as a significant CH<sub>4</sub> pathway in northern peatlands, however, in the Tropics this is still unknown. Within this context, we adopted an integrated approach using on-site measurements (CH<sub>4</sub>, porewater physicochemical characteristics) with genomics to investigate the role of hydrology, vegetation structure, and microbiome on CH<sub>4</sub> emission from fire-degraded tropical peatland in Brunei.</p><p>          We found for the first time that in degraded tropical peatlands of Southeast Asia, sedges transported 70-80% of the total CH<sub>4</sub> emission and significantly varied with values ranging from 1.22±0.13 to 6.15±0.57 mg CH<sub>4</sub> m<sup>-2</sup> hr<sup>-1</sup>, during dry and wet period, respectively. This variation was mainly attributed to water table position along with changes in sedge cover and porewater properties, which created more optimal methanogenesis conditions. Total emissions via this process might increase in the future as the extent of degraded tropical peatlands expands due to more frequent fire episodes and flooding.</p><p>          Further, we used 16S rRNA high-throughput sequencing to investigate the microbiomes in peat profile (above and below water table) as well as rhizo-compartments (Rhizosphere, Rhizoplane, Endosphere) of sedges. We found that the peat profile as well as rhizo-compartments of sedge harboured a higher number of methanogenic archaea in the order Methanomicrobiales and Methanobacteriales, compared to non-burnt and bulk soil, which further explains our findings of higher CH<sub>4</sub> emission from degraded tropical peatland areas covered with sedges. These insights into the impact of fire on hydrology, vegetation structure, and microbial community composition on CH<sub>4</sub> emissions provide an important basis for future studies on CH<sub>4</sub> dynamics in degraded tropical peatland areas.</p>

scholarly journals Lek-Like Mating System of the Monogamous Blue-Black Grassquit

The Auk ◽  
2001 ◽  
Vol 118 (2) ◽  
pp. 404-411 ◽  
Author(s):  
Juliana B. Almeida ◽  
Regina H. Macedo
Keyword(s):  
Sexual Selection ◽  
Mating System ◽  
Vegetation Structure ◽  
Selection Pressures ◽  
Ideal Candidate ◽  
Lek Mating

Abstract In this study, we investigated the role of display and mating system of the little known Neotropical Blue-black Grassquit (Volatinia jacarina). Males form aggregations and execute a highly conspicuous display, resembling traditional leks. Number of displaying males declined throughout the study period, though displaying intensity during the season showed no variation. Individual males had significantly different displaying rates and also defended territories of very different sizes, ranging from 13.0 to 72.5 m2, but we found no association between territory sizes and the average displaying rates of the resident males. There also is no association between displaying rates of males and size and vegetation structure of their territories. Four of seven nests were found within male territories and observations indicated that both sexes invest equally in caring for nestlings. Results suggest that the Blue-black Grassquit does not fit into the traditional lek mating system, contrary to what has been proposed in the scarce literature available. However, it is clear that these apparently monogamous birds behave like a lekking species. We speculate about the possibility that aggregation of nesting territories in this species may be due to sexual selection pressures, and suggest that the Blue-black Grassquit may be an ideal candidate to test Wagner's (1997) hidden-lek hypothesis.

scholarly journals Hominin Dispersal and Settlement East of Huxley’s Line: The Role of Sea Level Changes, Island Size, and Subsistence Behavior

2017 ◽  
Vol 58 (S17) ◽  
pp. S567-S582 ◽  
Author(s):  
Sue O’Connor ◽  
Julien Louys ◽  
Shimona Kealy ◽  
Sofía C. Samper Carro
Keyword(s):  
Sea Level ◽  
Sea Level Changes ◽  
Island Size ◽  
Hominin Dispersal
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