32 research outputs found
Immediate increase in isotopic enrichment in small mammals following the expansion of a great cormorant colony
Colonies of great cormorants (Phalacrocorax carbo) impact
terrestrial ecosystems through the transport of nutrients from aquatic to
terrestrial ecosystems. Deposited guano overload the ecosystem with N and P,
change soil pH and damage vegetation. The ways in which small mammals are
impacted, however, are little known. We aimed to evaluate the effects of an
expanding great cormorant colony, testing if the expansion immediately
increased the input of biogens into the forest ecosystem and, further, if the
growing influence of the colony was reflected in basal resources (plants and
invertebrates) and the hair of small mammals. δ15N and
δ13C signatures were analyzed in granivorous yellow-necked mice
(Apodemus flavicollis), omnivorous bank voles (Myodes
glareolus) and basal resources of animal and plant origin from the territory
of a colony of great cormorants situated near the Baltic Sea in west
Lithuania. We found that biogens transferred by great cormorants to the
terrestrial ecosystem affected the potential foods of the small mammals and
led to highly elevated and variable δ15N values. An increase of the
size of the colony in 2015 resulted in isotopic enrichment of the small
mammals in the zone of expansion in comparison to levels in 2014. The
increase of δ15N in A. flavicollis was 7.5 %
(p < 0.05) in the ecotone and 5.7 % in the expansion zone. The
decrease in δ13C signatures in A. flavicollis was 4.5 % (p < 0.1)
in the expansion zone and 3.1 % (p < 0.001)
in the colony. In M. glareolus, the decrease in δ13C
signatures was 8.5 % in the expansion zone, 3.3 % (p < 0.1) in
the control zone and 2.6 % in the ecotone. Isotopic niches (central
ellipses) of A. flavicollis in the colony and between the control
and expansion zones were separated in 2014 and 2015, while they partially
overlapped in the ecotone. The isotopic niches of M. glareolus in
2014 and 2015 were separated in the ecotone and had a small overlap in the
colony. For most of the resources tested, the isotopic signatures in the
established colony area were significantly higher than in the rest of
cormorant-inhabited area. In the colony, the δ15N values in plants
(16.9 ± 1.1 ‰) were higher than in invertebrates
(13.6 ± 0.4 ‰). In the ecotone, the δ15N
values were 12.0 ± 1.4 in plants and 14.7 ± 0.04 ‰ in invertebrates, while in the expansion zone they
were 7.2 ± 3.0 and 9.9 ± 3.8 ‰, respectively. δ15N-rich resources led to
increased δ15N values in the hair of A. flavicollis and
M. glareolus. Thus, biogens from the great cormorant colony
immediately affected small mammals through their food sources
Effect of biostimulants on cold resistance and productivity formation in winter rapeseed and winter wheat
The aim of the study was to investigate the effects of biostimulants on the resistance to freezing under laboratory-controlled cold conditions and on the growth, development, overwintering and productivity of winter rapeseed and winter wheat in natural field experiments. The effect of free amino acids, macroelements and microelements that contain biostimulants Ruter AA, Terra Sorb and Razormin was tested on cultivars of rapeseed, ‘Hornet H’, and winter wheat, ‘Skagen’ and ‘Kovas’, applying morphometrical methods. We found that biostimulants applied to rapeseed at BBCH 13–14 stage and to wheat at BBCH 14–15 stage under controlled cold stress conditions increased the freezing tolerance of seedlings. Biostimulants more actively increased the freezing resistance of rapeseed seedlings at –5°C compared to that of wheat seedlings. The temperature of –7°C was mortal to rape seedlings, while the resistance of wheat seedlings increased under the influence of the tested biostimulants compared to that of the control seedlings. In natural field experiments, these biostimulants produced a significant effect on plant growth in autumn, acclimation to the cold, plant overwintering, vegetation renewal and, due to this, formation of productivity elements. The effects of Razormin (200 mL/ha), Terra Sorb (2 L/ha) and Ruter AA (1 L/ha) were significantly higher on growth parameters of winter wheat compared to the productivity of winter rapeseed
Effect of biostimulants on cold resistance and productivity formation in winter rapeseed and winter wheat
The aim of the study was to investigate the effects of biostimulants on the resistance to freezing under laboratory-controlled cold conditions and on the growth, development, overwintering and productivity of winter rapeseed and winter wheat in natural field experiments. The effect of free amino acids, macroelements and microelements that contain biostimulants Ruter AA, Terra Sorb and Razormin was tested on cultivars of rapeseed, ‘Hornet H’, and winter wheat, ‘Skagen’ and ‘Kovas’, applying morphometrical methods. We found that biostimulants applied to rapeseed at BBCH 13–14 stage and to wheat at BBCH 14–15 stage under controlled cold stress conditions increased the freezing tolerance of seedlings. Biostimulants more actively increased the freezing resistance of rapeseed seedlings at –5°C compared to that of wheat seedlings. The temperature of –7°C was mortal to rape seedlings, while the resistance of wheat seedlings increased under the influence of the tested biostimulants compared to that of the control seedlings. In natural field experiments, these biostimulants produced a significant effect on plant growth in autumn, acclimation to the cold, plant overwintering, vegetation renewal and, due to this, formation of productivity elements. The effects of Razormin (200 mL/ha), Terra Sorb (2 L/ha) and Ruter AA (1 L/ha) were significantly higher on growth parameters of winter wheat compared to the productivity of winter rapeseed
First detection of Rickettsia helvetica in small mammals in Lithuania
A total of 489 small mammals belonging to seven species captured in Lithuania during 2013–2014 were investigated for Rickettsia pathogens. The overall prevalence of Rickettsia spp. was 27.6%, with a higher prevalence detected in Micromys minutus (45.9%), followed by Apodemus flavicollis (29.4%), Sorex araneus (25%) and Myodes glareolus (23.7%). Sequence analysis of the gltA gene and the 17 kDa protein coding gene revealed the presence Rickettsia helvetica. This study demonstrates not only the first reported presence of R. helvetica in small mammals in Lithuania but also the first report of R. helvetica in M. minutus more generally. Keywords: 17 kDa, gltA, Lithuania, Rickettsia helvetica, rodents, shrew