A comparison of manual and automatic moth sampling methods (Lepidoptera : Arctiidae, Geometridae) in a rain forest in Costa Rica

Sampling with UV fluorescent light tubes is a commonly used technique both in applied and basic insect studies. Our study compares the performance of two such methods: manual sampling (light towers) and automatic sampling (funnel light traps). The abundance, diversity, and body size of moths representing two species-rich families (Lepidoptera: Arctiidae, Geometridae) were analyzed in a lowland rain forest in Costa Rica (La Selva Biological Station, 10.4 degrees N, 84.0 degrees W) during 2003 and 2004. Light towers were equipped with two 15-W UV fluorescent tubes and were operated for 3 h in 16 nights. Traps equipped with single 8-W fluorescent tubes were run throughout 20 nights in the understory of the forest. In addition, parallel trap sampling was carried out in the canopy. A total of 1,238 arctiid moths representing 162 species and 1,769 geometrid moths representing 196 species were collected. In Geometridae, tower samples were significantly larger than trap samples. Towers also attracted a higher overall number of species. Very small geometrids (particularly of the subfamily Sterrhinae) were under-represented in trap samples, suggesting that this method is biased toward larger species. In arctiid moths, there were no significant differences in either the sample sizes, the number of species or in the size of the individuals sampled. Diversity calculated as Fisher's a was similar for towers and understory traps in both families. A major component of diversity was added with canopy trap samples for arctiid moths, but not for geometrid moths. In conclusion, ground-based tower sampling proved to be the most suitable method for geometrid moths, and trap sampling including both understory and canopy for arctiid moths. For full moth species inventories, a combination of both approaches is recommended

Field margins as rapidly evolving local diversity hotspots for ground beetles (Coleoptera : Carabidae) in northern China

The diversity of carabid assemblages at newly established field margins was compared to the diversity in surrounding fields and woodland habitats at Dongbeiwang village, Beijing. Carabids were sampled using 6 pitfalls per plot at a total of 12 plots in the year 2000. Although sampled only a year after their establishment, field margins harbored the most abundant and diverse carabids assemblages of all sites. More than a quarter of carabid species encountered were furthermore restricted to catches from field margins. Also woodland and fields under rotational wheat/maize cultivation harbored some unique species. Therefore, a short term establishment of field margins is effective in enhancing diversity and abundance of carabids, an important predator group in the agricultural landscape, while only the preservation of a heterogeneous landscape will enable the conservation of the overall species diversity

Asymmetric warming significantly affects net primary production, but not ecosystem carbon balances of forest and grassland ecosystems in northern China

We combine the process-based ecosystem model (Biome-BGC) with climate change-scenarios based on both RegCM3 model outputs and historic observed trends to quantify differential effects of symmetric and asymmetric warming on ecosystem net primary productivity (NPP), heterotrophic respiration (Rh) and net ecosystem productivity (NEP) of six ecosystem types representing different climatic zones of northern China. Analysis of covariance shows that NPP is significant greater at most ecosystems under the various environmental change scenarios once temperature asymmetries are taken into consideration. However, these differences do not lead to significant differences in NEP, which indicates that asymmetry in climate change does not result in significant alterations of the overall carbon balance in the dominating forest or grassland ecosystems. Overall, NPP, Rh and NEP are regulated by highly interrelated effects of increases in temperature and atmospheric CO2 concentrations and precipitation changes, while the magnitude of these effects strongly varies across the six sites. Further studies underpinned by suitable experiments are nonetheless required to further improve the performance of ecosystem models and confirm the validity of these model predictions. This is crucial for a sound understanding of the mechanisms controlling the variability in asymmetric warming effects on ecosystem structure and functioning

China's national nature reserve network shows great imbalances in conserving the country's mega-diverse vegetation

The National Nature Reserve (NNR) network forms a central element in China's governmental strategy to conserve the country's vast biodiversity and its varied ecosystems. Nonetheless, the effectiveness of the existing NNR network in protecting China's highly diverse habitats and the fauna and flora they contain has remained unclear. Here, we analyze how comprehensively the existing NNR network protects China's vegetation diversity, identifying potential gaps to inform future NNR designations. Covering ~15.7% of China's land area, the existing nature reserve network contains 18 main vegetation types and 26 sub-types. All main vegetation types are also contained in the National-level Nature Reserves (NNRs), but to highly differing degrees. NNRs cover ~24.0% of China's grasslands, but only ~3.3% of the country's monsoon forests. With regards to main vegetation regions, about 41.4% of the Qinghai-Xizang Plateau is covered by NNRs, in contrast to only ~4.6% of the region representing warm-temperate deciduous broad-leaved forests. In five main vegetation regions, NNRs cover 50% of the vegetation types in their respective region. Overall, NNR size increases and fragmentation decreases from China's south-east to its western provinces. The resulting, extremely uneven distribution of NNRs across China limits their effectiveness in protection the country's plant diversity treasure trove. The country's NNR network therefore needs significant adjustments to effectively conserve China's valuable natural resources for future generations

Improving the pollinator pantry: Restoration and management of open farmland ponds enhances the complexity of plant-pollinator networks

In line with general biodiversity losses across agricultural landscapes, insect pollinators have experienced recent sharp declines. A range of conservation measures have been developed to address these declines, with plant-pollinator interaction networks providing key insights into the effectiveness of these measures. For the first time, we studied interactions between three diurnal pollinator groups (bees, hoverflies, and butterflies) and insect-pollinated plants to understand how they are affected by pond management and restoration. Major network contributors were identified, and important network-level parameters compared at nine farmland ponds under different management strategies to assess management effects on plant-pollinator interactions: three ‘overgrown’ tree-covered ponds, three ‘long-term managed ponds’ kept in an open-canopy, early- to mid-successional state by periodic interventions involving tree and sediment removal, and three ‘recently restored ponds’, initially heavily overgrown with woody vegetation, and subsequently rapidly transformed into an early succession state through major tree and sediment removal. Interaction complexity, as measured by the metrics ‘links per species’, ‘linkage density’, Fisher’s alpha and Shannon’s Diversity, was higher for both long-term managed and recently restored ponds compared to overgrown ponds. Several network-level parameters indicated that highest complexity levels were found at recently restored ponds due to their substantially higher plant diversity. Bipartite interaction analysis suggests major benefits of pond management and restoration for agricultural pollinator assemblages. We strongly advocate the inclusion of ponds in conservation strategies and policies aimed at pollinators - ponds should be part of the pollinator pantry

Plant invasions in China – challenges and chances

Invasive species cause serious environmental and economic harm and threaten global biodiversity. We set out to investigate how quickly invasive plant species are currently spreading in China and how their resulting distribution patterns are linked to socio-economic and environmental conditions. A comparison of the invasive plant species density (log species/ log area) reported in 2008 with current data shows that invasive species were originally highly concentrated in the wealthy, southeastern coastal provinces of China, but they are currently rapidly spreading inland. Linear regression models based on the species density and turnover of invasive plants as dependent parameters and principal components representing key socio-economic and environmental parameters as predictors indicate strong positive links between invasive plant density and the overall phytodiversity and associated climatic parameters. Principal components representing socio-economic factors and endemic plant density also show significant positive links with invasive plant density. Urgent control and eradication measures are needed in China’s coastal provinces to counteract the rapid inland spread of invasive plants. Strict controls of imports through seaports need to be accompanied by similarly strict controls of the developing horticultural trade and underpinned by awareness campaigns for China’s increasingly affluent population to limit the arrival of new invaders. Furthermore, China needs to fully utilize its substantial native phytodiversity, rather than relying on exotics, in current large-scale afforestation projects and in the creation of urban green spaces

Once a pond in time: employing palaeoecology to inform farmland pond restoration

The restoration of highly terrestrialized farmland ponds that combines the removal of woody vegetation and pond sediment greatly enhances aquatic biodiversity. Nonetheless, questions remain regarding the historical precedent of pond restoration, and particularly if post-restoration aquatic macrophyte communities resemble pre-terrestrialization assemblages. We used a paleoecological approach to address these questions for a typical, recently restored farmland pond in Norfolk, eastern England. Plant and animal remains in pond sediment cores were used to infer decadal-centennial scale changes to pond communities and to identify past pond management events. We then evaluated the resemblance of restored and historical assemblages by comparisons with contemporary post-restoration vegetation data. Based on changes in the abundance of terrestrial leaf remains and other indicators (increases followed by declines of aquatic organisms), the study pond appears to have a long history (going back to the early-1800s) of canopy management (at least three inferred management events), but after the mid-1970s, steady and substantial increases in terrestrial indicators, suggest cessation of management resulting in uninterrupted terrestrialization. Aquatic macrophyte communities arising after restoration showed some similarities with historical assemblages, but also contained apparently new species. This study demonstrates how paleolimnological methods can improve understanding of pond ecological histories to better inform restoration targets and practices. Implications for Practice Paleolimnological methods can be successfully employed at small, human-made ponds to assess past biological communities and trajectories of ecological change. Restoration of heavily terrestrialized farmland ponds through major woody vegetation and sediment removal mimics periodic management activities undertaken over past centuries and is essential to the maintenance of open canopy conditions and biodiversity conservation. Caution must be taken when setting restoration targets for farmland ponds as rare macrophyte species indicative of high water quality may not necessarily return to restored pond habitats due to fragmentation effects associated with the loss of local populations and/or in-pond eutrophication development

A new role for pond management in farmland bird conservation

Biodiversity declines in agricultural landscapes represent a major conservation challenge. In the UK, some agricultural landscapes contain high pond densities, but many farmland ponds have become terrestrialised since the 1960s, with input of organic material resulting in a decrease in the size and depth of ponds that eventually transform into wet woodland habitats. Pond management, including removal of overhanging scrub and sediment, has proven highly effective in enhancing freshwater biodiversity. However, the implications of this management for farmland bird assemblages are unknown. Bird surveys were undertaken at recently managed, open, macrophyte-dominated and at highly terrestrialised, macrophyte-free ponds in the intensively cultivated farmland of North Norfolk, UK. The diversity, abundance and composition of bird assemblages visiting these ponds were compared to determine responses to pond management by tree and mud removal. Avian species richness, abundance and bird-visit frequencies were all higher at open farmland ponds. The observed patterns of bird occurrence were best explained by management-induced reductions in tree shading that resulted in aquatic macrophyte-dominance likely associated with high emergent invertebrate prey abundance. Moreover, we predict that open-canopy ponds offer greater habitat heterogeneity than overgrown ponds, allowing diversified bird use. Overgrown, terrestrialised ponds were preferred by some woodland bird species. Gamma diversity across the entire pondscape exceeded all individual pond alpha diversity measures by an order of magnitude, suggesting distinct variation in the bird assemblages visiting farmland ponds during different successional stages. Pond management that generates a mosaic of pond successional stages, including open-canopy, macrophyte-dominated ponds, could help to address the long-term decline of farmland birds. We strongly advocate increased agro-ecological research in this field, combined with greater emphasis on ponds and pond management options in agri-environment schemes

Different response patterns of epigaeic spiders and carabid beetles to varying environmental conditions in fields and semi-natural habitats of an intensively cultivated agricultural landscape

Agricultural intensification has resulted in major losses of biodiversity due to landscape homogenization and an increasing use of agrochemicals. It has often been assumed that associated changes in environmental conditions are impacting composition and diversity of two main ground-dwelling generalist predator taxa, carabid beetles and epigaeic spiders, in similar ways. Here, we test how variations in environmental conditions at local scales (plant diversity and total soil nitrogen, Ntot) and landscape-scale (mean patch size) affect species composition, richness and abundance of ground beetles and epigaeic spiders in semi-natural and cultivated habitats of an agricultural landscape. We specifically test the hypotheses that both taxa are more diverse in semi-natural than cultivated habitats, but that due to their weaker dispersal ability, ground beetles are more strongly linked to local factors than spiders. Our results indicate that in our study area, carabid diversity shows no significant difference between semi-natural habitats and cropland, while spider abundance is significantly enhanced in semi-natural habitats. Ntot significantly affected carabid species richness and abundance, but had a limited influence on spider abundances. The species composition of both carabids and spiders was influenced by plant diversity, while Ntot played a significant role in determining spider assemblages but not carabid composition. There was no significant effect of the mean patch size in the surroundings landscape on either spider or carabid species. Nonetheless, in landscapes with small patch sizes, spider abundance decreased with increasing Ntot, while in landscapes with large sized patches, this relationship was reversed. The differences in responses of these taxa to local and landscape-scale environmental factors suggests that scale- and taxon-specific targets need to be established to improve the efficiency of measures aimed at enhancing ecosystem services provisions by these key pest control agents

Predictability of species diversity by family diversity across global terrestrial animal taxa

Aim: Although biodiversity is in sharp decline around the globe, collectiing precise information on changes in overall species richness remains extremely challenging. Efficient and reliable proxy methods are therefore needed, with the diversity of higher taxa representing one such potential proxy for species‐level diversity. Nonetheless, the stability of using this measure across different regions and animal taxa at the global scale has never been investigated thoroughly. Location: Global. Time period: Up to 2016. Major taxa studied Animalia. Methods: We used a large global dataset containing published studies on diversity in the terrestrial Animalia to analyse the relationship between diversity at the family, genus and species level across different orders. Results: Family and species diversity were positively correlated, with the strongest correlations in Diptera, Hemiptera and Coleoptera. Correlations were slightly weaker in family–species than in genus–species relationships, whereas differences were stronger in observed richness than in diversity indices. Across all taxa, family–species correlations of Shannon diversity index values were independent of sample size, and they showed limited variation across biomes for the three orders containing sufficient case studies for this analysis. Based on the Shannon diversity index, the species diversity per site increased linearly with the increase in family diversity, with an average species : family diversity index ratio of 2.5, slightly lower than the ratio of 2.7 for observed species and family richness values. Main conclusions: Our study confirmed that recording family‐level diversity can be a meaningful proxy for determining species‐level diversity patterns in biodiversity studies, and trade‐offs between identification costs and retained information content need to be considered when using higher taxon surrogacy