scholarly journals Let the Seeds Fall Where They May: Investigating the Effect of Landscape Features on Fine-Scale Seed Dispersal

2000 ◽  
Author(s):  
Monica Grasty
2020 ◽  
Vol 107 (3) ◽  
pp. 413-422 ◽  
Author(s):  
Monica R. Grasty ◽  
Pamela G. Thompson ◽  
Elizabeth C. Hendrickson ◽  
Avery E. Pheil ◽  
Mitchell B. Cruzan

2019 ◽  
Author(s):  
Samantha J. Green ◽  
Bryan J. Boruff ◽  
Cyril C. Grueter

AbstractRecent improvements in tracking technologies have resulted in a growing number of fine-scale animal movement studies in a variety of fields from wildlife management to animal cognition. Most studies assume that an animal’s “optimal” foraging route is linear, ignoring the role the energy landscape can play in influencing movement efficiency. Our objective was to investigate whether landscape features that affect movement costs; topographic variation, and super and substrate, influence the movement of chimpanzees (Pan troglodytes) in a rugged, montane environment. We tested for route re-use and preferential use of human-made trails and ridge tops using 14 months of focal follow data from 14 individuals and maps of established chimpanzee trails. Chimpanzees travelled on human-made trails significantly more than expected and showed weak preference for use of ridge tops for travel. Line density analysis demonstrated route re-use in chimpanzees and uncovered a network of high-use routes across their range. To our knowledge, this is the first study to empirically demonstrate route re-use and preferential use of human-made trails for travel by chimpanzees. We discuss the energetic and cognitive benefits of trail use and the implications for chimpanzee sociality. By applying the latest GIS analytical techniques to fine-scale movement data, this study demonstrates the importance of incorporating landscape features in predictive animal movement models.


Author(s):  
Russell L. Steere

Complementary replicas have revealed the fact that the two common faces observed in electron micrographs of freeze-fracture and freeze-etch specimens are complementary to each other and are thus the new faces of a split membrane rather than the original inner and outer surfaces (1, 2 and personal observations). The big question raised by published electron micrographs is why do we not see depressions in the complementary face opposite membrane-associated particles? Reports have appeared indicating that some depressions do appear but complementarity on such a fine scale has yet to be shown.Dog cardiac muscle was perfused with glutaraldehyde, washed in distilled water, then transferred to 30% glycerol (material furnished by Dr. Joaquim Sommer, Duke Univ., and VA Hospital, Durham, N.C.). Small strips were freeze-fractured in a Denton Vacuum DFE-2 Freeze-Etch Unit with complementary replica tooling. Replicas were cleaned in chromic acid cleaning solution, then washed in 4 changes of distilled water and mounted on opposite sides of the center wire of a Formvar-coated grid.


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