The role of Natura 2000 in relation to breeding birds decline on multiple land cover types and policy implications

Abstract

The Natura 2000 network of protected sites is the pillar of biodiversity conservation in Europe. Although the Natura 2000 network directly addresses birds, these have shown worrying declining trends. It is therefore crucial to assess the potential contribution of Natura 2000 conservation measures. In this paper, we use a replicable method to model bird trends in the period 2000–2015 and the effects of Natura 2000 protection, across land cover classes, on regional abundances and local species richness and diversity. We model bird trends in Veneto, a North-Eastern Italian Region with areas among the richest in bird species in Italy. Bird data were derived from the national breeding bird monitoring scheme. Breeding birds showed declining trends at the regional level, confirming national and continental trends, particularly on agricultural and natural areas. The land cover class, rather than Natura 2000, mostly influenced population trends; however, it was possible to observe slightly higher estimates of species richness and diversity in Natura 2000 sites. Despite the absolute higher estimates of richness and diversity over the investigated period, farmland and woodland bird species had steeper declining trends inside Natura 2000 than outside, matching the values of the areas outside the network at the end of the survey period. We conclude that the Natura 2000 network capacity to buffer biodiversity loss and act as a species-pool for non-protected areas is decreasing over time, mainly with regards to farmland and woodland birds. Natura 2000 implementation must be improved: conservation objectives and measures, management, and monitoring should be better integrated into existing plans and funding should be made more efficiently available for Natura 2000.

Introduction

Impoverishment and homogenization of the land mosaic are among the main drivers of biodiversity decline at regional and global scale (McKinney & Lockwood, 1999), and birds are among the most studied animal taxa that respond to climate and land cover change (de Chazal & Rounsevell, 2009; Jetz, Wilcove, & Dobson, 2007). To halt these drivers, several policy tools and initiatives have been envisaged (Boere & Rubec, 2002; Butchart et al., 2010) as they are also recognized to be one of the causes of land-use change and nature conservation (Donald et al., 2007). Among commonly applied approaches is the designation of protected areas for conservation, owing to the general assumption that they host more biodiversity than other areas (Gray et al., 2016; Peach et al., 2018).

The Natura 2000 network of protected areas, the pillar of biodiversity conservation in Europe, is the largest of the very few coordinated nature conservation actions explicitly aimed at improving ecological connectivity at the continental scale (Campagnaro et al., 2019; European Commission, 2011; Orlikowska et al., 2016; Wurzel, 2008). The network is composed of protected Natura 2000 sites designated under the European Union (EU) Nature Directives: Birds Directive (79/409/EEC, repealed by the 2009/147/EC) and Habitats Directive (1992/43/EEC). The network aims at the protection of a range of habitats and species of conservation concern. In particular, the Birds Directive established a protection regime for all native bird species occurring in the wild. Member States must classify Special Protection Areas (SPA) specifically for the habitats of 193 threatened bird species and regularly occurring migratory species. In 1992, with the application of the Habitats Directive, the network was integrated with the inclusion of Sites of Community Importance (SCI) which, after conservation measures are applied, are designated as Special Areas of Conservation (SAC), aiming at the conservation of the 233 habitat types listed in Annex I of the Directive and about 900 species listed in Annex II. The habitat types range from natural to seminatural, and farmlands and forests cover 40 % and 50 % of the protected sites, respectively (Olmeda et al., 2018).

In contrast to this continental conservation effort, the main trends of land cover change since the early 1990s are showing a continuous increase in artificial areas, a loss of agricultural areas, and an increase of forest land in Europe (EEA, 2017a). Agricultural intensity changed according to heterogeneous patterns, with the establishment of more intensive practices wherever highly suitable areas were available (Kuemmerle et al., 2016). In EU countries, the intensification of production and consequent negative effects on farmland bird populations are in part due to the price-support policies, like the Common Agricultural Policy (CAP) (Donald et al., 2001; Reif & Vermouzek, 2019). In this context, the EU has oriented its most recent CAP towards the sustainable management of natural resources and has activated a monitoring and evaluation framework to assess its performance. The CAP identifies agricultural areas with high species and habitat diversity as “high nature value farmland” (HNV) and adopted the farmland bird index (FBI), an indicator of population trends of 36 bird species conceived within the Pan-European Common Bird Monitoring Scheme (PECBMS) of the European Bird Census Council (EBCC), to assess its performance. Data needed to calculate this index come from nationwide samples of annual breeding bird surveys. The measures of this index confirmed that the decline of HNV (EEA, 2017a, 2017b) has resulted in a sharp decline of common farmland birds (Gregory et al., 2005). Several other scientific studies confirmed that European bird species are declining, although the rate of the trend may differ between guilds and levels of habitat specialization (Donald et al., 2001; Gregory et al., 2007; Holling, 2019; Inger et al., 2014). Moreover, biodiversity losses at a continental scale do not always correspond to those at regional and local scales (Chase et al., 2019; Primack et al., 2018).

These negative trends legitimize asking whether the Natura 2000 conservation efforts have achieved their targets and proved to contribute to the protection of bird diversity. Indeed, the two EU Nature Directives have proved to be beneficial for bird species (Donald et al., 2007; Koschová et al., 2018; Pellissier et al., 2013). However, almost 30 years after the Natura 2000 implementation, the impact of the measures taken have not shown the expected advancement towards the overall objective of the Directives (Milieu et al., 2016). According to the results from the last Article 12 reporting on the Birds Directive (EEA, 2015), only half of the EU bird populations are considered secure; whereas 32 % of bird species have a threatened, declining, or depleted population status. Around one-third of the EU breeding bird species are increasing, both in the short- and long-term, but a number are decreasing. It is also evident that further monitoring is needed, since 19 % and 30 % of EU breeding bird population trends are unknown in the short- and long-term, respectively.

A few comparisons have been made on the bird populations within and outside Natura 2000 sites. For example, a gap analysis made by Albuquerque et al. (2013) concluded that the relationship between European bird species richness patterns and Natura 2000 sites is poor. In Sweden, to achieve the conservation of three forest birds, actions should also be implemented outside Natura 2000 sites, particularly when the protected sites are small (Orlikowska et al., 2020). In Portugal, Santana et al. (2013) found that only flagship and specialized fallow field species variations in richness and abundance were more favourable inside Natura 2000 sites than in those nearby and stressed the need to improve correspondence between conservation and agricultural policies. In France, Natura 2000 sites showed a greater abundance of many common specialist bird species (Pellissier et al., 2013). In Lower Saxony, Germany, the area covered by maize, which negatively influenced bird trends, was mitigated by Natura 2000, and Natura 2000 alone positively affected farmland birds and non-field nesters (Jerrentrup et al., 2017). These observations have been confirmed at European level: from 2001 to 2010 the abundance of most bird species not included in Annex I of the Birds Directive improved with increased Natura 2000 coverage (Pellissier et al., 2020).

Although large-scale analyses may attract more attention from EU policymakers, the implementation of Natura 2000 should consider “regional and local characteristics” (Art. 2, Habitats Directive). Consequently, many Member States decided to delegate implementation and monitoring of the Natura 2000 network to sub-national administrative levels. In Italy, the administrations of the Regions and Autonomous Provinces are in charge of the identification, monitoring and management of Natura 2000 sites, and report data and information about the sites to the Ministry of the Environment, which refers these to the European Commission. An estimation of the contribution of Italian SPA and other protected areas performed more than ten years ago concluded that these covered all areas with the maximum possible bird species richness (Maiorano et al., 2007). In partial contradiction, a gap analysis which used a nationwide annual breeding bird monitoring scheme (Florenzano et al., 2009), suggested that the Italian network of protected areas fails to conserve farmland birds, while it guarantees a good level of protection to birds of open mountain habitats (Campedelli et al., 2010). After further years of Nature Directives implementation, a sub-national approach is needed to bridge the gap between reaching a good conservation status of habitats and species at a national level while defining conservation objectives and measures at a protected site level (Campagnaro et al., 2018; Louette et al., 2011).

In this paper, we assess the contribution of the Natura 2000 network in buffering the decline of bird abundances, species richness and diversity between 2000 and 2015, across land cover types in the Veneto Region, North-Eastern Italy, 22.5 % of which is covered by the Natura 2000 network. We assume that the decline of bird species population known for Europe will be confirmed in Veneto, but with a positive contribution of Natura 2000 in the mitigation of this trend. Due to its biogeographical position and topography, Veneto has some of the areas among the richest in bird species, particularly in the Alps and the Venice lagoon (Maiorano et al., 2007). Agricultural, seminatural and forest lands cover 78 % of the Natura 2000 network in Veneto. Therefore, when assessing species richness and diversity, we focused on common farmland and forest bird species and on the land cover classes that may contain their suitable habitats. We expect that the Natura 2000 contribution will be more relevant for these species, at least in terms of species richness and diversity. We used the data from the annual breeding bird monitoring scheme, the same used by Campedelli et al. (2010) and its continuation (Rete Rurale Nazionale & LIPU, 2018), which, being nationwide, ensures the possible replication of the method in other Italian regions.