Solidago canadensis impacts on native plant and pollinator communities in different-aged old fields

Abstract

Abstract:1. Pollination is an important ecosystem service as many agricultural crops such as fruit trees are pollinated by insects. Agricultural intensification, however, is one of the main drivers resulting in a serious decline of pollinator populations worldwide. 2. In this study pollinator communities were examined in twelve apple orchards surrounded by either homogeneous or heterogeneous landscape in Hungary. Pollinators (honey bees, wild bees, hoverflies) were surveyed in the flowering period of apple trees. Landscape heterogeneity was characterized in circles of 300, 500 and 1000 m radius around each orchard using Shannon's diversity and Shannon's evenness indices. 3. We found that pollination success of apple was significantly related to the species richness of wild bees, regardless the dominance of honey bees. 4. Diversity of the surrounding landscape matrix had a marginal positive effect on the species richness of hoverflies at 300m, positive effect on the species richness of wild bees at 500m radius circle, while evenness of the surrounding landscape enhanced the abundance of wild bees at 500m radius circle. Flower resources in the groundcover within the orchards supported honey bees. 5. Therefore maintenance of semi-natural habitats within 500m around apple orchards is highly recommended to enhance wild pollinator communities and apple production. Apple is one of the most important insect pollinated crops in the European Union, accounting 51 for 16% of the EU's total economic gains attributed to insect (particularly bee) pollination 52 (Leonhardt et al., 2013). Most apple varieties are cross-pollinated and insect pollination not 53 only affects the quantity of apple production, but can also have marked impacts on the quality 54 of the fruits, influencing size, shape and their market price (Garratt et al., 2014a). The most 55 common insect pollinator of apple is the honey bee (Apis mellifera); however, it is not the bees (Bosch & Blas, 1994). Hoverflies (Syrphidae) have also been observed with pollen loads 63 containing a high proportion of compatible fruit pollen (Kendall, 1973). Agricultural and Forest Entomology 64In the temperate zone, pollinator insects are under threat from a number of limiting 65 factors, such as climate change (Rader et al., 2013), human disturbance (Goulson et al., 66 2008), agricultural intensification (Kearns et al., 1998; Steffan-Dewenter et al., 2005; 67 Fitzpatrick et al., 2006; Memmott et al., 2007), and landscape fragmentation (Aizen & 68 Feisinger, 2003; Diekötter & Crist, 2013), which leads to less effective pollination and 69 reduces agricultural production (Floyd, 1992; Garibaldi et al., 2011a Garibaldi et al., , 2013 (Kremen et al., 2002; Brittain et al., 2013). Maintaining diverse communities, 94Apple is the most important fruit tree in Hungary, as it provides 60 % of the total 95Hungarian fruit production, and currently amounts to 400-600 thousand tons annually on We constructed generalized linear mixed models (GLMM) for each response variab...

Invasive goldenrods affect abundance and diversity of grassland ant communities (Hymenoptera: Formicidae)

“…The impact of goldenrod invasion has already been studied in other groups of animals with a documented decrease in species richness, diversity and abundance of butterflies, wild bees and hoverflies but only a decrease in abundance in the case of ground beetles (de Groot et al 2007;Skórka et al 2007;Fenesi et al 2015). The strength of these relationships depended on the trophic position occupied by the group of insects, i.e.…”

“…Goldenrod is a strongly melliferous plant, but the time of flowering is probably too short and too late to provide enough food for invertebrates (Moroń et al 2009). Moreover, an overall decline in species richness and densities of different groups of invertebrates in areas with goldenrod (de Groot et al 2007;Skórka et al 2007;Moroń et al 2009;Fenesi et al 2015) may cause a decrease in the amount of available food for carnivorous ant species (Litt et al 2014), mainly M. scabrinodis. Many species of ants also feed on the honeydew produced by aphids.…”

“…In consequence, goldenrods establish stable and widespread monocultures, with high densities of sprouts. Such large changes in vegetation also bring further consequences for organisms at higher trophic levels, both herbivores and predators (de Groot et al 2007;Moroń et al 2009;Skórka et al 2010;Fenesi et al 2015). An investigation into the climatic niche of Solidago showed that its range and density will increase, mainly in the south-eastern part of Europe (Weber 2001).…”

Do Landscape Structure and Socio-Economic Variables Explain the Solidago Invasion?

“…Invasive species of Solidago are able to better utilize resources for biomass production than co-occurring plant species native to Central Europe (Szymura and Szymura 2015). The increase of the cover of alien Solidago species in patches of vegetation is correlated with a decrease in species richness (Hejda et al 2009;Del Fabbro et al 2013;Fenesi et al 2015) and alters spontaneous succession (Bornkamm 2007;Bartha et al 2014). Meadows, invaded by goldenrods, have lower bird species richness and lower numbers of breeding pairs than uninvaded ones (Skórka et al 2010).…”

“…Meadows, invaded by goldenrods, have lower bird species richness and lower numbers of breeding pairs than uninvaded ones (Skórka et al 2010). The invasion of Solidago also caused a decrease in the abundance, species richness and diversity of pollinators: wild bees, hoverflies and butterflies (Moroń et al 2009, but see also Fenesi et al 2015). The increase of the area covered by alien goldenrods reduces visitation of native flowers by pollinators (Fenesi et al 2015).…”