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The nuthatch, Sitta europaea L., is a small (23 g), cavity-nesting woodland bird which, since the 1970s, has been expanding its range in Britain. However, within this range, the species is notably scarce in an area of eastern England. This gap in the species distribution could arise for several reasons including habitat quality, local landscape structure, regional landscape structure and climate. Field surveys and logistic models of breeding nuthatch presence/absence were used to investigate the relative influences of habitat quality, landscape structure and climate on the prevalence of nuthatches in eastern England. Field surveys of woods in the study area indicated that habitat quality was sufficient to support a nuthatch population. A model of habitat occupancy in relation to local landscape structure, developed in the Netherlands, was applied to the study area. The number of breeding pairs predicted for the study area by the model was lower than expected from habitat area alone, suggesting an additional effect of isolation. However, observed numbers were even lower than those predicted by the model. To evaluate the possible roles of climate and large-scale landscape structure on distribution, presence/absence data of breeding nuthatches at the 10-km grid square scale were related to variables describing climate and the amount and dispersion of broadleaved woodland. While climate in the study area appeared suitable, models including landscape variables suggested that the study area as a whole was unlikely to support nuthatches. Although suitable habitat was available, woodland in the study area appeared to be too isolated from surrounding nuthatch populations for colonisation to be successful. This situation may change if current increases in both national and regional populations continue, thus increasing the number of potential colonists reaching the study area.

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In The Netherlands, fragmentation of (semi)natural ecosystems is regarded as a major nature conservation problem. The current Dutch Nature Conservation Policy Plan proposes a spatial network consisting of existing nature reserves, nature redevelopment areas and corridor zones. One of the objectives is to stop the assumed decline of biodiversity due to fragmentation. In this contribution we show that breeding birds are affected by the spatial distribution of their habitat. We also show how problems due to fragmentation can be solved by integrating landscape ecological research data into planning procedures. Fragmented bird populations show metapopulation characteristics, dependent on the degree of fragmentation. This can be concluded from pattern studies, in which presence or absence patterns are correlated with spatial characteristics. Metapopulation dynamics were used, and the frequency of local extinction and of recolonization were related to size of habitat patches and spatial position in the landscape. The conclusion is that, depending on the spatial scale, landscape fragmentation is a threat to birds. On the basis of empirical data, statistical and metapopulation models are being developed to be used to evaluate spatial planning scenarios and to support decision making about which scenario is closest to the planning aims.

Melman, Th.C.P., A.G.M. Schotman, H.A.M. Meeuwsen, R.A. Smidt, B. Vanmeulebrouk en H. Sierdsema, 2016. Ex-ante-evaluatie ANLb-2016 Ex-ante evaluation ANLb2016 for learning management; a first look at size and spatial quality of managed units in the new agri-environmental system in the Netherlands.Outine: An ex ante evaluation was performed for the new system for agricultural nature and landscape in the Netherlands (ANLb-2016), in which managers (collectives of farmers) have more responsibility as before. Objects were size, location in suitable areas and spatial coherence of the managed plots. Special attention is paid to the quality as meadow bird habitat. A comparison is made with 2010. Attention is paid to four agricultural habitats: grassland, arable fields, dry and wet veining. The focus is put on meadow birds: much knowledge is available and the greater part of the managed area concerns this group. Results: the managed area declined from about 143,000 to 90,000 ha (of which approx 23.000ha concerns expiring contracts of which continuation is uncertain). Meadow bird management is about 62-64% in suitable area (58% in 2010); 65% of it is fairly concentrated, 35% more or less dispersed. With the so called heavy management, as far as situated within suitable area, is expected to result for about 50% into a reasonable to good quality habitat. Recommendation: To improve the management it is crucial to come to objectified insights, shared by all parties concerned: managers (collectives of farmers), scientists and policy-makers. Basic items for this moment are reconnition of suitable areas, lower limits for spatial coherence and habitat quality. Here, so called learning management (learning by doing, bench mark, sharing knowledge and experience) may be very important to come to ecological effects.Trefwoorden: Agrarisch natuurbeheer, leefgebiedtypen, ruimtelijke kwaliteit, ruimtelijke samenhang

Today, many seabird species nest in port areas, which are also necessary for human economic activity. In this paper, we evaluate, using a metapopulation model, the possibilities for creating alternative breeding sites for the Common Tern (Sterna hirundo) in the Rhine-MeuseScheldt estuary. We explore 22 scenarios that differ with respect to (1) loss of breeding habitat in port areas, (2) location and size of newly created habitat, and (3) coexistence of old and new habitat. Results indicate that loss of port area habitats results in a serious 41% decline in the breeding population. When the loss in ports is compensated for within the ports, the decline was negligible. Fourteen scenarios result in an increase of the Common Tern metapopulation. In these, extra breeding habitat is created outside the ports in fish-rich waters, resulting in a potential metapopulation increase of 25%. However, the period of overlap between lost and newly created habitat strongly affects the results. A gap between the removal of old and the creation of new breeding areas might cause a drop in the metapopulation level of 30%. The population recovery from this drop might take more than 100 years due to slow recolonization. Our results suggest that conservation of seabird species should be evaluated on a metapopulation scale and that the creation of new habitat may help to compensate for habitat loss in other areas. Furthermore, the results indicate that overlap between the existence of old and newly created breeding habitats is crucial for the success of compensation efforts. However, new locations should be carefully selected, because not only is the suitability of the breeding grounds important, but ample fish availability nearby is also key.

The consequences of bird mortality caused by collisions with wind turbines are increasingly receiving attention. So‐called acceptable mortality limits of populations, that is, those that assume that 1%–5% of additional mortality and the potential biological removal (PBR), provide seemingly clear‐cut methods for establishing the reduction in population viability. We examine how the application of these commonly used mortality limits could affect populations of the Common Starling, Black‐tailed Godwit, Marsh Harrier, Eurasian Spoonbill, White Stork, Common Tern, and White‐tailed Eagle using stochastic density‐independent and density‐dependent Leslie matrix models. Results show that population viability can be very sensitive to proportionally small increases in mortality. Rather than having a negligible effect, we found that a 1% additional mortality in postfledging cohorts of our studied populations resulted in a 2%–24% decrease in the population level after 10 years. Allowing a 5% mortality increase to existing mortality resulted in a 9%–77% reduction in the populations after 10 years. When the PBR method is used in the density‐dependent simulations, the proportional change in the resulting growth rate and carrying capacity was species‐independent and largely determined by the recovery factor (Fr). When Fr = 1, a value typically used for robust populations, additional mortality resulted in a 50%–55% reduction in the equilibrium density and the resulting growth rate. When Fr = 0.1, used for threatened populations, the reduction in the equilibrium density and growth rate was about 5%. Synthesis and applications. Our results show that by allowing a mortality increase from wind farm collisions according to both criteria, the population impacts of these collisions can still be severe. We propose a simple new method as an alternative that was able to estimate mortality impacts of age‐structured stochastic density‐dependent matrix models.