scholarly journals Distress feeding of depredatory birds in Sunflower and Sorghum protected by bioacoustics

2017 ◽  
Author(s):  
S.S. Mahesh ◽  
V. Vasudeva Rao ◽  
G. Surender ◽  
D.A. Kiran kumar ◽  
K. Swamy

ABSTRACTOne of the most ignored aspects of bioacoustic technology employed worldwide is lack of understanding between acclimatisation and distress feeding by depredatory birds. Acclimatisation results in gradual increase in resistance to bioacoustics in comparison to distress feeding, which makes sudden surge in instances of feeding by depredatory birds. Acclimatisation and distress feeding are independent functions of feeding behaviour. Distress feeding in itself is a function of physiological conditions of bird, extent of cropped area, distance traveled to obtain food, population dynamics, other natural habitats and cropping pattern in an area and is greatly influenced by them. There are no studies conducted to understand the distress feeding of birds in agricultural landscape. Experiments proved that bioacoustics could offer protection against distress feeding by birds although at reduced efficiency.

Insects ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 305
Author(s):  
Alexandra Siffert ◽  
Fabian Cahenzli ◽  
Patrik Kehrli ◽  
Claudia Daniel ◽  
Virginie Dekumbis ◽  
...  

The invasive Drosophila suzukii feeds and reproduces on various cultivated and wild fruits and moves between agricultural and semi-natural habitats. Hedges in agricultural landscapes play a vital role in the population development of D. suzukii, but also harbor a diverse community of natural enemies. We investigated predation by repeatedly exposing cohorts of D. suzukii pupae between June and October in dry and humid hedges at five different locations in Switzerland. We sampled predator communities and analyzed their gut content for the presence of D. suzukii DNA based on the COI marker. On average, 44% of the exposed pupae were predated. Predation was higher in dry than humid hedges, but did not differ significantly between pupae exposed on the ground or on branches and among sampling periods. Earwigs, spiders, and ants were the dominant predators. Predator communities did not vary significantly between hedge types or sampling periods. DNA of D. suzukii was detected in 3.4% of the earwigs, 1.8% of the spiders, and in one predatory bug (1.6%). While the molecular gut content analysis detected only a small proportion of predators that had fed on D. suzukii, overall predation seemed sufficient to reduce D. suzukii populations, in particular in hedges that provide few host fruit resources.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Károly Lajos ◽  
Ferenc Samu ◽  
Áron Domonkos Bihaly ◽  
Dávid Fülöp ◽  
Miklós Sárospataki

AbstractMass-flowering crop monocultures, like sunflower, cannot harbour a permanent pollinator community. Their pollination is best secured if both managed honey bees and wild pollinators are present in the agricultural landscape. Semi-natural habitats are known to be the main foraging and nesting areas of wild pollinators, thus benefiting their populations, whereas crops flowering simultaneously may competitively dilute pollinator densities. In our study we asked how landscape structure affects major pollinator groups’ visiting frequency on 36 focal sunflower fields, hypothesising that herbaceous semi-natural (hSNH) and sunflower patches in the landscape neighbourhood will have a scale-dependent effect. We found that an increasing area and/or dispersion of hSNH areas enhanced the visitation of all pollinator groups. These positive effects were scale-dependent and corresponded well with the foraging ranges of the observed bee pollinators. In contrast, an increasing edge density of neighbouring sunflower fields resulted in considerably lower visiting frequencies of wild bees. Our results clearly indicate that the pollination of sunflower is dependent on the composition and configuration of the agricultural landscape. We conclude that an optimization of the pollination can be achieved if sufficient amount of hSNH areas with good dispersion are provided and mass flowering crops do not over-dominate the agricultural landscape.


Crustaceana ◽  
2021 ◽  
Vol 94 (7) ◽  
pp. 775-795
Author(s):  
Alfred-Ştefan Cicort-Lucaciu ◽  
Gabriel-Lucian Herlo

Abstract In the last two hundred years, the Mureş River Floodplain has suffered major changes caused by dike constructions, meander cutting, and by the transformation of the natural landscape into an agricultural one. In this environmental context, we wanted to find out the degree to which large branchiopod species still survive in the Mureş Floodplain area. Every stagnant aquatic habitat encountered in 2019 in the Mureş Floodplain Natural Park was sampled. For the habitats where more species co-occur, urgent preservation actions must be taken. Most of the species prefer open habitats and have survived in the wheel ruts on agricultural lands. In the absence of natural habitats, the importance of this habitat type becomes a major one. The forest advantages species related to shady habitats, such as Chirocephalus diaphanus. We have found several individuals in the park that showed black spots on their bodies, characteristic of the black disease of fairy shrimp. The presence of the disease only in the populations from wheel ruts suggests that vehicles which make these ruts, could be the carriers of the disease.


2014 ◽  
Vol 83 (4) ◽  
pp. 325-351 ◽  
Author(s):  
Józef Banaszak ◽  
Halina Ratyńska

ABSTRACT Changes in communities of wild bees (Apiformes) were studied in relation to changes in vegetation in six permanent plots (natural forest habitats in the Wielkopolska National Park, and semi-natural habitats in the agricultural landscape near Turew) at the end of four decades (starting from the late 1970s). In 2008-2010, as many as 100 species of Apiformes were recorded there, which is more than reported in earlier decades. The most stable bee communities were those in forest habitats (oak-hornbeam forest, oak forest). Substantial qualitative and quantitative changes in vegetation and bee communities were recorded only after the renaturalisation of a former xerothermic grassland, which had become overgrown with shrubs and trees as a result of plant succession. Human interference (e.g. the felling of some trees growing along a road, clearance of understorey shrubs, ploughing of roadside margins) at selected refuge habitats in the agricultural landscape led to short-term fluctuations in bee abundance and diversity, but an increasing trend in abundance was noted.


2000 ◽  
Vol 2000 ◽  
pp. 3-3
Author(s):  
D.P.N. Schweitzer ◽  
B.J. Tolkamp ◽  
I. Kyriazakis

Study of short-term feeding behaviour (STFB) could improve the understanding of variation in daily intake in dairy cows. STFB is generally measured in short bouts (e.g. visits to feeders) that are clustered in larger bouts (or meals). The value of bout analysis depends strongly on the choice of an appropriate bout. Before bouts can be grouped into meals, a meal criterion (MC, that is: the longest non-feeding interval accepted as part of a meal) must be estimated. Tolkamp and Kyriazakis (1999) criticised existing methods and recently developed a new technique to estimate meal criteria. These log-normal models were developed on basis of the idea that eating bouts end when animals are satiated (i.e., in a state of low feeding motivation) (Tolkamp and Kyriazakis, 1999). This implies that feed consumption during the relevant eating bout will result in a gradual increase in satiety. This will be associated with an increase in the probability of cows ending a bout. In this study we will analyse whether meals are a more biologically relevant unit of STFB than the short feeding bouts (i.e. visits) that are routinely recorded.


2021 ◽  
Author(s):  
Patrizia Zamberletti ◽  
Khadija Sabir ◽  
Thomas Opitz ◽  
Olivier Bonnefon ◽  
Edith Gabriel ◽  
...  

AbstractIn agricultural landscapes, the amount and organization of crops and semi-natural habitats (SNH) have the potential to promote a bundle of ecosystem services due to their influence on ecological community at multiple spatio-temporal scales. SNH are relatively undisturbed and are often source of complementary resources and refuges, supporting more diverse and abundant natural pest enemies. However, the nexus of SNH proportion and organization with pest suppression is not trivial. It is thus crucial to understand how the behavior of pest and auxiliary species, the underlying landscape structure, and their interaction may influence conservation biological control (CBC). Here, we develop a generative stochastic landscape model to simulate realistic agricultural landscape compositions and configurations of fields and linear elements. Generated landscapes are used as spatial support over which we simulate a spatially explicit predator-prey dynamic model. We find that SNH boost predator population, but predator movement from hedges to fields is fundamental for an efficient pest regulation by auxiliaries and to decrease pesticide treatments. Moreover landscape elements may lead to different effects on pest reduction depending on the considered scale. Integration of species behaviors and traits with landscape structure at multiple scales are needed to provide useful insights for CBC.


2018 ◽  
Author(s):  
Richard Odemer ◽  
Peter Rosenkranz

ABSTRACTIn the last decade, the use of neonicotinoid insecticides increased significantly in the agricultural landscape and meanwhile considered a risk to honey bees. Besides the exposure to pesticides, colonies are treated frequently with various acaricides that beekeepers are forced to use against the parasitic mite Varroa destructor. Here we have analyzed the impact of a chronic exposure to sublethal concentrations of the common neonicotinoid thiacloprid (T) and the widely used acaricide τ-fluvalinate (synthetic pyrethroid, F) - applied alone or in combination - to honey bee colonies under field conditions. The population dynamics of bees and brood were assessed in all colonies according to the Liebefeld method. Four groups (T, F, F+T, control) with 8-9 colonies each were analyzed in two independent replications, each lasting from spring/summer until spring of the consecutive year. In late autumn, all colonies were treated with oxalic acid against Varroosis. We could not find a negative impact of the chronic neonicotinoid exposure on the population dynamics or overwintering success of the colonies, irrespective of whether applied alone or in combination with τ-fluvalinate. This is in contrast to some results obtained from individually treated bees under laboratory conditions and confirms again an effective buffering capacity of the honey bee colony as a superorganism. Yet, the underlying mechanisms for this social resilience remain to be fully understood.


Diversity ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 12
Author(s):  
Francesco Liccari ◽  
Maurizia Sigura ◽  
Enrico Tordoni ◽  
Francesco Boscutti ◽  
Giovanni Bacaro

In intensively used and human-modified landscapes, biodiversity is often confined to remnants of natural habitats. Thus, identifying ecological networks (ENs) necessary to connect these patches and maintain high levels of biodiversity, not only for conservation but also for the effective management of the landscape, is required. However, ENs are often defined without a clear a-priori evaluation of their biodiversity and are seldom even monitored after their establishment. The objective of this study was to determine the adequate number of replicates to effectively characterize biodiversity content of natural habitats within the nodes of an EN in north-eastern Italy, based on vascular plant diversity. Plant communities within habitat types of the EN’s nodes were sampled through a hierarchical sampling design, evaluating both species richness and compositional dissimilarity. We developed an integrated method, consisting of multivariate measures of precision (MultSE), rarefaction curves and diversity partitioning approaches, which was applied to estimate the minimum number of replicates needed to characterize plant communities within the EN, evaluating also how the proposed optimization in sampling size affected the estimations of the characteristics of habitat types and nodes of the EN. We observed that reducing the total sampled replicates by 85.5% resulted to sufficiently characterize plant diversity of the whole EN, and by 72.5% to exhaustively distinguish plant communities among habitat types. This integrated method helped to fill the gap regarding the data collection to monitor biodiversity content within existing ENs, considering temporal and economic resources. We therefore suggest the use of this quantitative approach, based on probabilistic sampling, to conduct pilot studies in the context of ENs design and monitoring, and in general for habitat monitoring.


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