Habitat islands outside nature reserves – Threatened biodiversity hotspots of grassland specialist plant and arthropod species

Abstract

In transformed landscapes, many populations of grassland specialist plant and animal species live outside the few protected areas and are often preserved on 'small natural features' (SNFs) such as road verges, field margins and rocky outcrops. In the steppe and forest steppe zones of Eurasia ancient burial mounds (kurgans) are widespread SNFs providing refuge for grassland species. Based on a large-scale botanical and zoological survey of 138 kurgans in Hungary, we compared the management regimes, the presence of threatening factors and the conservation potential of kurgans embedded in non-protected transformed landscapes and in protected areas. We found that kurgans extend the borders of the protected areas by maintaining populations of grassland specialist plants and arthropods (ants, orthopterans, true bugs and rove beetles) even in transformed landscapes. We revealed that the lack of proper management, the presence of anthropogenic disturbances and encroachment of woody species are the most considerable threats to the long-term maintenance of biodiversity on kurgans located outside the protected areas. For their effective conservation a new approach is needed, which can cope with the small area and dispersed localities of the kurgans and can integrate them into the network of other SNFs on a landscape-level. As the ecological importance of kurgans is disproportionate to their size conservation actions focusing on their protection offers a greater rate of return of the efforts than can be expected in case of larger continuous sites.

Fragmented dry grasslands preserve unique components of plant species and phylogenetic diversity in agricultural landscapes

“…The expansion of agricultural fields and the exponential spread of urban infrastructure (such as roads, canals and settlements) has led to the irreversible loss of many grassland habitats (Deák et al 2016;Lindborg et al 2014). As a result, in intensively managed landscapes elements of grassland biodiversity have often been able to survive in small fragments that were not suitable for agriculture or for infrastructural developments (Bhagwat and Rutte 2006;Deák et al 2020;Löki et al 2019;Molnár et al 2017). These fragments often harbour populations of grassland specialist plants, act as an integral element of the semi-natural habitat network, and have a considerable role in maintaining landscape-scale diversity.…”

“…These fragments often harbour populations of grassland specialist plants, act as an integral element of the semi-natural habitat network, and have a considerable role in maintaining landscape-scale diversity. Nevertheless, they are often considered to be of lower conservation priority compared to continuous grassland stands, and do not receive any legal protection (Lindborg et al 2014;Deák et al 2020). Grassland fragments, either of primary (i.e.…”

Legacies of past land use challenge grassland recovery – An example from dry grasslands on ancient burial mounds

“…The estimated number of these mounds is more than 600,000 in Eurasia and they are typical landscape elements from Hungary to Mongolia (Deák et al 2016a(Deák et al , 2019. A considerable proportion of these mounds still hold grassland vegetation; hence, mounds are valued as being stepping stones or biodiversity hotspots for grassland specialist plant and animal species even in transformed agricultural landscapes (Bede and Csathó 2019;Tóth et al 2019;Deák et al 2020). Despite their cultural importance and steep slopes, many of the mounds have been exposed to ploughing and afforestation works in the past centuries (Deák et al 2016a, b).…”

“…cessation of crop production and cutting of non-native plantations) were not followed by any other restoration measures; thus the grasslands are recovering spontaneously. Another challenge is the isolated situation of the mounds: most of them are surrounded by arable fields, therefore, post-restoration management by grazing or mowing is particularly challenging (Deák et al 2020).…”

Turning old foes into new allies – harnessing drainage canals for biodiversity conservation in desiccated novel ecosystems

“…Responsible land stewardship in these landscapes requires a complex understanding of the role of drainage canals harbouring novel ecosystems, and comprehensive guidelines must be developed for their management, in order to reconcile conservation purposes and immediate economic needs. At present, the scientific literature offers limited guidance for this endeavour but the emerging concepts of novel ecosystem management (Hobbs et al, 2009; Deák et al, 2020) and reconciliation ecology (Rosenzweig, 2003; Chapman et al, 2018) offer promising avenues. Considering these new fields of ecology, we aimed to understand the ecological role of the drainage canal network of a large, heavily drained European lowland region composed of a mosaic of intensive arable fields and semi-natural grasslands.…”