Size matters: the value of small populations for wintering waterbirds

Protecting systematically selected areas of land is a major step towards biodiversity conservation worldwide. Indeed, the identification and designation of protected areas more often than not forms a core component of both national and international conservation policies. In this paper we provide an overview of those Special Protection Areas and Ramsar Sites that have been classified in Great Britain as of 1998/99 for a selection of wintering waterbird species, using bird count data from the Wetland Bird Survey. The performance of this network of sites is remarkable, particularly in comparison with published analyses of networks elsewhere in the world. Nevertheless, the current site-based approach, whilst having the great benefit of simplicity, is deliberately biased towards aggregating species at the expense of the more dispersed distribution species. To ensure that the network continues successfully to protect nationally and internationally important waterbird populations, efforts now need to concentrate on the derivation of species-specific representation targets and, in particular, the ways in which these can be incorporated into the site selection process. Although these analyses concern the performance of protected areas for waterbirds in Great Britain, the results have wide-ranging importance for conservation planning in general and the design of protected area networks

Protected areas and freshwater biodiversity: a novel systematic review distils eight lessons for effective conservation

Protected areas are a global cornerstone of biodiversity conservation and restoration. Yet freshwater biodiversity is continuing to decline rapidly. To date there has been no formal review of the effectiveness of protected areas for conserving or restoring biodiversity in rivers, lakes, and wetlands. We present the first assessment using a systematic review of the published scientific evidence of the effectiveness of freshwater protected areas. Systematic searches returned 2,586 separate publications, of which 44 provided quantitative evidence comprising 75 case studies. Of these, 38 reported positive, 25 neutral, and 12 negative outcomes for freshwater biodiversity conservation. Analysis revealed variable relationships between conservation effectiveness and factors such as taxa assessed, protected area size and characteristics, International Union for Conservation of Nature (IUCN) protected area category, and ecoregion. Lack of effectiveness was attributed to many anthropogenic factors, including fishing (often with a lack of law enforcement), water management (abstraction, dams, and flow regulation), habitat degradation, and invasive non‐native species. Drawing on the review and wider literature we distil eight lessons to enhance the effectiveness of protected areas for freshwater biodiversity conservation. We urge policymakers, protected area managers, and those who fund them to invest in well‐designed research and monitoring programs and publication of evidence of protected area effectiveness

Refining soil organic carbon stock estimates for China’s palustrine wetlands

Palustrine wetlands include all bogs, fens, swamps and marshes that are non-saline and which are not lakes or rivers. They therefore form a highly important group of wetlands which hold large carbon stocks. If these wetlands are not protected properly they could become a net carbon source in the future. Compilation of spatially explicit wetland databases, national inventory data and in-situ measurement of soil organic carbon (SOC) could be useful to better quantify SOC and formulate long-term strategies for mitigating global climate change. In this study, a synergistic mapping approach was used to create a hybrid map for palustrine wetlands for China and to estimate their SOC content. Total SOC storage in palustrine wetlands was estimated to be 4.3±1.4 Pg C, with a SOC density of 31.17 (±10.55) kg C m-2 in the upper 1 m of the soil layer. This carbon stock is concentrated in Northeast China (49%) and the Qinghai-Tibet Plateau (41%). Given the large pool of carbon stored in palustrine wetlands compared to other soil types, we suggest that urgent monitoring programmes on SOC should be established in regions with very few datasets, but where palustrine wetlands appear to be common such as the Tibet region and Northwest China

Testing the heterospecific attraction hypothesis with time-series data on species co-occurrence

The distributional patterns of actively moving animals are influenced by the cues that the individuals use for choosing sites into which they settle. Individuals may gather information about habitat quality using two types of strategies, either directly assessing the relevant environmental factors, or using the presence of conspecifics or heterospecifics as an indirect measure of habitat quality. We examined patterns of heterospecific attraction with observational time-series data on a community of seven waterbird species breeding in artificial irrigation ponds. We fitted to the data a multivariate logistic regression model, which attributes the presence–absence of each species to a set of environmental and spatial covariates, to the presence of con- and heterospecifics in the previous year and to the presence of heterospecifics in the same year. All species showed a clear tendency to continue breeding in the same sites where they were observed in the previous year. Additionally, the presence of heterospecifics, both in the previous year and in the same year, generally increased the probability that the focal species was found breeding on a given pond. Our data thus give support for the heterospecific attraction hypothesis, though causal inference should be confirmed with manipulative experiments

Groundwater dependent wetlands [in the Wetland book: II]

The relative importance of groundwater in the development and maintenance of hydrological and ecological character is recognized as an important feature that distinguishes so-called “groundwater-dependent” wetlands. A categorisation is presented here according to three types of groundwater dependent ecosystems (1: subterranean or cave; 2: surface expressions of groundwater discharge; and 3: ecosystems dependent on subsurface presence of groundwater). Beyond these, we recognise eight degrees of dependence based on ecology-hydrology linkages that make explicit the hydrology, biology, soil/sediment/rock relationships arranged in increasing requirement for groundwater permanence (from intermittent to seasonal to permanent, and (soil) moisture to saturation). The classification is applied to situations where groundwater wetlands have become subject to changing hydrological conditions