Defining Patterns and Rates of Natural vs. Drought Driven Aquatic Community Variability Indicates the Ongoing Need for Long Term Ecological Research

Most ecologists have used climate change, as an omnipresent pressure, to support their findings in researching the vulnerability of specific taxa, communities, or ecosystems. However, there is a widespread lack of long-term biological, biocoenological, or community data of periods longer than several years to ascertain patterns as to how climate change affects communities. Since the 1950s, southern Europe has faced an ongoing trend of drying and loss of precipitation. A 13-year research program in the Dinaric karst ecoregion of Croatia aimed to comprehensively track emergence patterns of freshwater insects (true flies: Diptera) in a pristine aquatic environment. Three sites, spring, upper, and lower tufa barriers (calcium carbonate barriers on a barrage lake system that act as natural damns), were sampled monthly over 154 months. This coincided with a severe drought event in 2011/2012. This was the most significant drought (very low precipitation rates for an extended period of time) in the Croatian Dinaric ecoregion since the start of detailed records in the early 20th century. Significant shifts in dipteran taxa occurrence were determined using indicator species analysis. Patterns of seasonal and yearly dynamics were presented as Euclidian distance metrics of similarity in true fly community composition compared at increasing time intervals, to ascertain the degree of temporal variability of similarity within the community of a specific site and to define patterns of similarity change over time. Analyses detected significant shifts in community structure linked to changes in discharge regimes, especially to the drought period

Controlling premature fruit drop of cultivar Idared by using α-naphthaleneacetic acid

Fruit drop before reaching technological maturity is one of the core problems in the apple industry. The aim of this paper is to examine the effect of the chemicals VBC 30033 based on aminoethoxyvinylglycine (AVG) and Dirager based on α-naphtalenacetic acid on the prevention of fruit drop of apple cultivar Idared, as affected by the time of application, the number of applications and the concentration. The research was conducted from 2009 to 2011 at the experimental field of the Faculty of Agriculture in Novi Sad. The special focus was placed on the double and triple applications of NAA which were considered the most effective in preventing fruit drop. The triple application of NAA 5 ppm and NAA 10 ppm showed equal effectiveness, therefore the treatment NAA 5 ppm is recommended due to the reduced use of the chemical