scholarly journals Local extinctions of obligate frugivores and patch size reduction disrupt the structure of seed dispersal networks

Ecography ◽  
2018 ◽  
Vol 41 (11) ◽  
pp. 1899-1909 ◽  
Author(s):  
Jamille de Assis Bomfim ◽  
Paulo R Guimarães ◽  
Carlos A. Peres ◽  
Gustavo Carvalho ◽  
Eliana Cazetta
2019 ◽  
Vol 5 (6) ◽  
pp. eaav6699 ◽  
Author(s):  
Carine Emer ◽  
Mauro Galetti ◽  
Marco A. Pizo ◽  
Pedro Jordano ◽  
Miguel Verdú

Species on Earth are interconnected with each other through ecological interactions. Defaunation can erode those connections, yet we lack evolutionary predictions about the consequences of losing interactions in human-modified ecosystems. We quantified the fate of the evolutionary history of avian–seed dispersal interactions across tropical forest fragments by combining the evolutionary distinctness of the pairwise-partner species, a proxy to their unique functional features. Both large-seeded plant and large-bodied bird species showed the highest evolutionary distinctness. We estimate a loss of 3.5 to 4.7 × 104 million years of cumulative evolutionary history of interactions due to defaunation. Bird-driven local extinctions mainly erode the most evolutionarily distinct interactions. However, the persistence of less evolutionarily distinct bird species in defaunated areas exerts a phylogenetic rescue effect through seed dispersal of evolutionarily distinct plant species.


2020 ◽  
Vol 102 (4) ◽  
Author(s):  
M. A. F. dos Santos ◽  
V. Dornelas ◽  
E. H. Colombo ◽  
C. Anteneodo

2015 ◽  
Vol 9 (15) ◽  
pp. 1727-1732 ◽  
Author(s):  
Alireza Motevasselian ◽  
William G. Whittow

Author(s):  
S. Muhamud Kayat ◽  
M. T. Ali ◽  
M. K. M. Salleh ◽  
M.H. M. Rusli ◽  
N. Ramli ◽  
...  

2019 ◽  
Vol 18 (1) ◽  
pp. 43-46
Author(s):  
Murtala Aminu-Baba ◽  
Mohammad Kamal A. Rahim ◽  
Farid Zubir ◽  
Adamu Y. Iliyasu ◽  
Mohd Fairus Mohd Yusoff ◽  
...  

A compact triband microstrip patch MIMO antenna is proposed for WLAN applications. The antenna consists of two patches antenna elements, which are orthogonally placed to each other for high isolation at 2.4, 2.8 and 5.8 GHz frequency bands. On its ground plane, a Complementary Split Ring Resonators (CSRRs) is etched for size reduction and multiband generation. The proposed compact MIMO antenna covers an entire size of 58 x 45 x 1.6 mm3, with the patch size of 13.3 x 17.1 mm2. A 79% size reduction at 2.45 GHz was achieved for miniaturization, with a very low mutual coupling (S21 and S12) of -32 dB at all bands.


2020 ◽  
Vol 648 ◽  
pp. 111-123
Author(s):  
C Layton ◽  
MJ Cameron ◽  
M Tatsumi ◽  
V Shelamoff ◽  
JT Wright ◽  
...  

Kelp forests in many regions are experiencing disturbance from anthropogenic sources such as ocean warming, pollution, and overgrazing. Unlike natural disturbances such as storms, anthropogenic disturbances often manifest as press perturbations that cause persistent alterations to the environment. One consequence is that some kelp forests are becoming increasingly sparse and fragmented. We manipulated patch size of the kelp Ecklonia radiata over 24 mo to simulate persistent habitat fragmentation and assessed how this influenced the demography of macro- and microscopic juvenile kelp within the patches. At the beginning of the experiment, patch formation resulted in short-term increases in E. radiata recruitment in patches <1 m2. However, recruitment collapsed in those same patches over the extended period, with no recruits observed after 15 mo. Experimental transplants of microscopic and macroscopic juvenile sporophytes into the patches failed to identify the life stage impacted by the reductions in patch size, indicating that the effects may be subtle and require extended periods to manifest, and/or that another life stage is responsible. Abiotic measurements within the patches indicated that kelp were less able to engineer the sub-canopy environment in smaller patches. In particular, reduced shading of the sub-canopy in smaller patches was associated with proliferation of sediments and turf algae, which potentially contributed to the collapse of recruitment. We demonstrate the consequences of short- and longer-term degradation of E. radiata habitats and conclude that habitat fragmentation can lead to severe disruptions to kelp demography.


2018 ◽  
Vol 60 (1) ◽  
pp. 42-45
Author(s):  
Tuan Quang Nguyen ◽  
Van Lam Nguyen ◽  
Thai Son Nguyen ◽  
Thi Minh Hue Pham ◽  
◽  
...  

Sign in / Sign up

Export Citation Format

Share Document