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Biodiversity conservation and monitoring – engagement and motivations of citizen scientists

100%

Grodzińska-Jurczak M. , Kobierska H. , Tusznio J.

nr 25

Usage of agrobiodiversity conservation practices among farmers in Niger State, Nigeria

100%

Kayode A. O. , Awoyemi A. O. , Adesiji G. B.

tom 4[58]

No evidence for a positive response of biomass production to species diversity in an experimental grassland

84%

Ding X. , Wang Y. , Yu S.

nr 4

Plant diversity is generally thought to enhance productivity, driven by either (1) chance inclusion of highly productive species in more diverse communities or (2) niche-based resource acquisition with competitive interactions increasing resource use efficiency. Here, we ask whether weeding, as employed in most experiments to date, might contribute to the positive diversity-productivity relationship reported for many grasslands. Using all 82 species from our local pool, we constructed 357 experimental grassland plots (2 × 4 m each), arranged as a completely randomized experiment in an arable field prepared to minimize existing seed bank. The plots were sown to vary species richness (1, 2, 4, 6, 8, 10, 15, 20, 25, 30, 35 or 40 species) and were maintained under both ambient conditions and experimental drought. A single monoculture plot was maintained for all 82 species, and each of the other eleven species richness levels was replicated 25 times. Plots were maintained strictly without weeding, and aboveground biomass was measured at 17, 19, 27 and 29 months after the start of this experiment. No single measure of biodiversity was significantly correlated with productivity consistently across all four sampling periods. Furthermore, there were only weak overall effects of six biodiversity variables (the species richness planted, observed, and sampled; Shannon diversity, effective species richness and evenness in the sampled area) on productivity under either precipitation treatment. Regression analysis identified no equation that used a consistent subset of the biodiversity measures as predictors. In view of these transient and insubstantial effects, results from previous experiments that employed weeding treatments are suspect as tests of the hypothesis that biodiversity has positive effects on productivity.

How does recent vegetation reflects previous systems of forest management?

84%

Szymura T. H.

tom Vol. 60, nr 4

859--862

It is known that historical coppicing could lead to developing thermophilous oak forests (habitat 91I0 according to NATURA 2000, in Kwiatkowski 2004), but this management system is recently unknown in Poland. In this paper we present the results of researching the historical documentation considering past methods of forest management in Sudety Mountains foothills (Silesia, Poland, Central Europe). Results of this research show that coppicing was most popular in the period ca 1835–1890, and focused on production of high quality oak tanbark (mirror tanbark). In the end of 19th century the area of coppiced forest for tanbark production was assessed at 16,000 ha. The decline of financial efficiency of this production led to conversion of coppiced forest into high forests, applying coppice-with-standard systems as transient kind of management. The historical knowledge suggests that thermophilous oak forest vegetation, observed recently in Sudety Mts. foothills, can be considered as an effect of past forest management and also necessity of active management in order to maintain this habitat.

Wzbogacenie oporu środowiska jako kierunek rozwoju metod biologicznych

67%

Dabrowski Z. T.

nr 3

The difference between biotic potential of a species and its actual abundance defines the environmental resistance or the effect of all factors that limit the biotic potential. The paper reviews practical exploration of major limitation factors in suppression of the exponential growth of a pest population under „unlimited” carrying capacity (food availability) of cultivated crop in agrocenosis. The following methods are presented: (a) using detrimental alternated food quality of resistant crop cultivars affecting pest population growth and the value of moderate level of resistance in the integrated pest management (IPM); (b) saving natural enemies by using selectively insecticides to upgrade the conservation biological control agents and (c) biodiversity and habitat management to provide suitable environment for natural enemies. The existing gaps in the scientist’s collected experimental data and knowledge and farmer’s practices on the pesticide selectivity for natural enemies still lead to some pest outbreaks in Poland. The evolution in research priorities and recommendations on the role of natural enemies in various agrocenoses by the IOBC working group on “Landscape management for functional biodiversity” indicated the shift from an individual field scale to the landscape scale and the needs for multidiscipline approach.