scholarly journals Bark-stripping of Common Buckthorn by Goats During Managed Browsing on Bur Oak Savannas

2021 ◽  
Author(s):  
Neal Mundahl ◽  
Ryan Walsh
Keyword(s):  
Invasive Plants ◽  
Cumulative Effects ◽  
Selective Feeding ◽  
Bark Stripping ◽  
Large Seed ◽  
Oak Savannas ◽  
Bur Oak

Abstract Goats are being used increasingly to manage woody invasive plants in woodland habitats, but their specific impacts on those plants over a period of time during active, periodic browsing has not been documented. This study investigated bark-stripping by goats browsing on common buckthorn in savanna habitats, focusing on possible size-selective feeding and the cumulative effects of repeated, periodic browsing over a 3-year period. When surveyed after the first browsing period, bark was stripped selectively on buckthorn stems 20 to 60 mm in diameter. Approximately 60% of all stripped stems were completely girdled, but only 14-17% of stems were bark-stripped. After five browsing periods, 66% of standing stems displayed bark stripping and 39% were completely girdled. Buckthorn densities were reduced by 90% compared to the first browsing period, the decline resulting mostly from consumption of foliage and terminal shoots of small (<20 mm) buckthorn and bark-stripping resulting in top-kill in intermediate-sized (20-60 mm) plants. Large buckthorn (>60 mm) were largely unimpacted by goats. Relatively few (28%) seedling buckthorn were browsed by goats, although >90% of 2nd-year plants were browsed. Buckthorn can be managed in part via goat browsing, but repeated, periodic browsing over several to many years may be necessary to produce a significant impact, and other techniques will be needed to eliminate large, seed-producing plants.

Recirculation versus flow-through rainbow trout laboratory Flavobacterium columnare challenge

2020 ◽  
Vol 139 ◽  
pp. 213-221
Author(s):  
C Birkett ◽  
R Lipscomb ◽  
T Moreland ◽  
T Leeds ◽  
JP Evenhuis
Keyword(s):  
Rainbow Trout ◽  
Environmental Parameters ◽  
Cumulative Effects ◽  
Flavobacterium Columnare ◽  
Replacement Rate ◽  
Bacterial Concentration ◽  
Water Replacement ◽  
Dose Concentration ◽  
Flow Through ◽  
And Control

Flavobacterium columnare immersion challenges are affected by water-related environmental parameters and thus are difficult to reproduce. Whereas these challenges are typically conducted using flow-through systems, use of a recirculating challenge system to control environmental parameters may improve reproducibility. We compared mortality, bacterial concentration, and environmental parameters between flow-through and recirculating immersion challenge systems under laboratory conditions using 20 rainbow trout families. Despite identical dose concentration (1:75 dilution), duration of challenge, lot of fish, and temperature, average mortality in the recirculating system (42%) was lower (p < 0.01) compared to the flow-through system (77%), and there was low correlation (r = 0.24) of family mortality. Mean days to death (3.25 vs. 2.99 d) and aquaria-to-aquaria variation (9.6 vs. 10.4%) in the recirculating and flow-through systems, respectively, did not differ (p ≥ 0.30). Despite 10-fold lower water replacement rate in the recirculating (0.4 exchanges h-1) compared to flow-through system (4 exchanges h-1), differences in bacterial concentration between the 2 systems were modest (≤0.6 orders of magnitude) and inconsistent throughout the 21 d challenge. Compared to the flow-through system, dissolved oxygen during the 1 h exposure and pH were greater (p ≤ 0.02), and calcium and hardness were lower (p ≤ 0.03), in the recirculating system. Although this study was not designed to test effects of specific environmental parameters on mortality, it demonstrates that the cumulative effects of these parameters result in poor reproducibility. A recirculating immersion challenge model may be warranted to empirically identify and control environmental parameters affecting mortality and thus may serve as a more repeatable laboratory challenge model.

A glimpse from the ancient world: What a gold necklace from Tillya-tepe reveals about opium in Afghanistan

Afghanistan ◽  
2020 ◽  
Vol 3 (2) ◽  
pp. 135-173
Author(s):  
Sara Peterson
Keyword(s):  
Opium Poppy ◽  
Ancient World ◽  
Cultural Importance ◽  
Large Seed ◽  
Potent Drug ◽  
Material Evidence ◽  
Societal Role

Among the six excavated burials at Tillya-tepe, in northern Afghanistan, was one occupied by an elite woman wearing a substantial necklace consisting of large gold beads shaped as seed-heads. The scale and fine workmanship of this necklace suggest that it was one of her most important possessions. It can be demonstrated that these large seed-heads are representations of poppy capsules, whose significance lies in the fact that they are the source of the potent drug opium. This necklace is the most outstanding object within a group of items decorated with poppy imagery, all of which were discovered in female burials. The opium poppy has long been a culturally important plant, and the implication of this identification is investigated in several contexts. Firstly, the proliferation of poppy imagery in the female burials at Tillya-tepe is examined, and then there is a discussion of material evidence for opium among relevant peoples along the Eurasian steppes. The particular cultural importance of opium is reviewed, leading finally to a proposal for the societal role of these women.

Aportaciones a la flora de la montaña palentina y su área de influencia. Contributions to the Palencia’s mountain flora and its influence area

2019 ◽  
Vol 37 ◽  
pp. 188-196
Author(s):  
Antonio Ruiz de Gopegui ◽  
Yolanda Ruiz
Keyword(s):  
Key Words ◽  
Invasive Plants ◽  
Endangered Plants ◽  
Influence Area ◽  
Palabras Clave

Contributions to the Palencia’s Mountain flora and its influence area. Palabras clave. Corología, flora amenazada, flora invasora, Palencia, España. Key words. Chorology, Endangered plants, Invasive plants, Palencia, Spain.

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