Search

Riparian zones are the paragon of transitional ecosystems, providing critical habitat and ecosystem services that are especially threatened by global change. Following consultation with experts, 10 key challenges were identified to be addressed for riparian vegetation science and management improvement: (1) Create a distinct scientific community by establishing stronger bridges between disciplines; (2) Make riparian vegetation more visible and appreciated in society and policies; (3) Improve knowledge regarding biodiversity—ecosystem functioning links; (4) Manage spatial scale and context‐based issues; (5) Improve knowledge on social dimensions of riparian vegetation; (6) Anticipate responses to emergent issues and future trajectories; (7) Enhance tools to quantify and prioritize ecosystem services; (8) Improve numerical modeling and simulation tools; (9) Calibrate methods and increase data availability for better indicators and monitoring practices and transferability; and (10) Undertake scientific validation of best management practices. These challenges are discussed and critiqued here, to guide future research into riparian vegetation. This article is categorized under:Water and Life > Nature of Freshwater EcosystemsWater and Life > Stresses and Pressures on EcosystemsWater and Life > Conservation, Management, and Awareness [ABSTRACT FROM AUTHOR]

Copyright of Ornithological Applications is the property of Oxford University Press / USA and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ecological restoration is key to counteracting anthropogenic degradation of biodiversity and to reducing disaster risk. However, there is limited knowledge of barriers hindering the wider implementation of restoration practices, despite high‐level political priority to halt the loss of biodiversity. In Europe, progress on ecological restoration has been slow and insufficient to meet international agreements and comply with European Union Nature Directives. We assessed European restoration experts' perceptions on barriers to restoration in Europe, and their relative importance, through a multiple expert consultation using a Delphi process. We found that experts share a common multi‐dimensional concept of ecological restoration. Experts identified a large number of barriers (33) to the advancement of ecological restoration in Europe. Major barriers pertained to the socio‐economic, not the environmental, domain. The three most important being insufficient funding, conflicting interests among different stakeholders, and low political priority given to restoration. Our results emphasize the need to increase political commitment at all levels, comply with existing nature laws, and optimize the use of financial resources by increasing funds for ecological restoration and eradicate environmentally harmful subsidies. The experts also call for the integration of ecological restoration into land‐use planning and facilitating stakeholders' collaboration. Our study identifies key barriers, discusses ways to overcome the main barriers to ER in Europe, and contributes knowledge to support the implementation of the European Biodiversity Strategy for 2030, and the EU 2030 Restoration Plan in particular. [ABSTRACT FROM AUTHOR]

Physiologic traits are promising indicators of population health in the face of rapidly changing environments. We obtained values of diverse physiologic parameters for Two-banded Plovers ( Charadrius falklandicus) in coastal sites in Patagonia, Argentina, with the objectives of determining the timeline in which these parameters become affected by the stress of capture and handling and of obtaining reference values for future monitoring of these populations. We analyzed packed cell volume, white blood cell profile, heterophil/lymphocyte ratio, bacterial agglutination titer, and total protein, glucose, triglyceride, and cholesterol levels in apparently healthy birds. Glucose, total white blood cell count, lymphocytes, and eosinophil levels showed changes with handling times >60 min after capture. The remaining parameters did not manifest significant alterations in response to capture and handling of up to 232 min (average=105.2, SD=56.7). Therefore, although researchers should attempt to obtain blood samples as soon as possible after capture, inclusion of physiologic parameters in monitoring studies of species not easily sampled in a few minutes, such as Two-banded Plovers and other shorebird species during migration, should not be discouraged. Here we provide a physiologic report for the species that can be considered as reference values during the nonbreeding season at Patagonian coastal sites. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mediterranean riparian forests are negatively impacted by drought. • Growth responses to climate and drought of four tree species were investigated. • Growth was reduced by drought and low spring-summer river flow. • Populus nigra and Fraxinus angustifolia were the most responsive species to drought. • Ash earlywood anatomy, and wood C and O isotopes also responded to drought. Mediterranean riparian forests have been altered by past use and are also negatively impacted by climate and hydrological droughts. However, we lack data on their historical changes in extent combined with multi-proxy, long-term assessments of tree growth and leaf gas exchange responses to climate, drought severity and river flow. These evaluations must also consider their current stand structure and the amount of lying deadwood which are proxies of river dynamics and forest maturity. To fill these research gaps, we studied four riparian tree species (Populus alba , Populus nigra , Fraxinus angustifolia and Ulmus minor) inhabiting a Mediterranean riparian forest located in north-eastern Spain. We quantified and analyzed: stand structure; lying deadwood; radial growth; relationships between growth, climate variables, the SPEI drought index and river flow; stable C (δ13C) and O (δ18O) isotopes in wood of P. alba , P. nigra and F. angustifolia ; and earlywood anatomy in F. angustifolia. Mature sites were dominated by P. nigra and F. angustifolia and showed the highest amount of decayed lying deadwood. Radial growth was reduced by drought and low spring-summer river flow. We found the highest growth responses to 3- (P. nigra , r = 0.62; P. alba , r = 0.46) or 12-month SPEI (F. angustifolia , r = 0.54; U. minor , r = 0.53). The coordinated decrease in δ18O and intrinsic water-use efficiency (WUE) in P. alba and P. nigra could involve an increase in stomatal conductance rate. P. alba and P. nigra were more enriched in δ18O than F. angustifolia , suggesting the former used more enriched shallow groundwater in dry periods. The F. angustifolia WUE and P. nigra δ18O series were positively and negatively correlated with the SPEI, respectively. The F. angustifolia hydraulic diameter decreased in response to drought, whereas its vessel density and WUE were positively associated. Overall, P. nigra and F. angustifolia were the species most responsive to drought. [ABSTRACT FROM AUTHOR]

One of the most salient causes of the degradation of freshwater systems is the physical habitat changes attributed to river damming. Environmental flows reduce such degradation but are still generally based on the requirements of aquatic species and disregard other biotic components of the ecosystem, such as riparian vegetation. Nevertheless, when environmental flow methods claim to consider riparian vegetation habitats and propose specific flows, their outcomes are rarely predicted quantitatively prior to their implementation. We used a dynamic floodplain vegetation model to analyze the riparian patch dynamics predicted for different flow regimes in two river stretches and to assess vegetation requirements to ensure long-term ecological maintenance and vitality of riparian structure in rivers with altered flow regimes. Furthermore, we assessed the capability of flushing flows to restore and manage riparian vegetation and the efficiency of environmental flows to satisfy riparian vegetation requirements. We found that vegetation encroachment is mainly prevented by floods with a recurrence interval of at least 2 years but that environmental flow regime planning aimed at complying with riparian vegetation requirements is watershed-specific. Additionally, reservoir flows controlled vegetation encroachment without causing severe geomorphic impacts on downstream river channels and with minor water losses to dam managers. [ABSTRACT FROM AUTHOR]

Global circulation models forecasts indicate a future temperature and rainfall pattern modification worldwide. Such phenomena will become particularly evident in Europe where climate modifications could be more severe than the average change at the global level. As such, river flow regimes are expected to change, with resultant impacts on aquatic and riparian ecosystems. Riparian woodlands are among the most endangered ecosystems on earth and provide vital services to interconnected ecosystems and human societies. However, they have not been the object of many studies designed to spatially and temporally quantify how these ecosystems will react to climate change-induced flow regimes. Our goal was to assess the effects of climate-changed flow regimes on the existing riparian vegetation of three different European flow regimes. Cases studies were selected in the light of the most common watershed alimentation modes occurring across European regions, with the objective of appraising expected alterations in the riparian elements of fluvial systems due to climate change. Riparian vegetation modeling was performed using the CASiMiR-vegetation model, which bases its computation on the fluvial disturbance of the riparian patch mosaic. Modeling results show that riparian woodlands may undergo not only at least moderate changes for all flow regimes, but also some dramatic adjustments in specific areas of particular vegetation development stages. There are circumstances in which complete annihilation is feasible. Pluvial flow regimes, like the ones in southern European rivers, are those likely to experience more pronounced changes. Furthermore, regardless of the flow regime, younger and more water-dependent individuals are expected to be the most affected by climate change. [ABSTRACT FROM AUTHOR]

The article presents a study which examined whether reverse movements of red knots occurred during their migration in Argentina. Resightings of birds individually marked in San Antonio Oeste or the flyway at two staging sites in 2006, 2007, 2009 and 2010 were analysed to investigate whether reverse movements occurred between them. The movements were found to have occurred in all years of the study.

We review the conservation issues facing migratory shorebird populations that breed in temperate regions and use wetlands in the non-breeding season. Shorebirds are excellent model organisms for understanding ecological, behavioural and evolutionary processes and are often used as indicators of wetland health. A global team of experienced shorebird researchers identified 45 issues facing these shorebird populations, and divided them into three categories (natural, current anthropogenic and future issues). The natural issues included megatsunamis, volcanoes and regional climate changes, while current anthropogenic threats encompassed agricultural intensification, conversion of tidal flats and coastal wetlands by human infrastructure developments and eutrophication of coastal systems. Possible future threats to shorebirds include microplastics, new means of recreation and infectious diseases. We suggest that this review process be broadened to other taxa to aid the identification and ranking of current and future conservation actions. [ABSTRACT FROM AUTHOR]

1. Millions of shorebirds migrate each year through a small number of highly productive staging areas where they often conflict with fisheries interests. Delaware Bay, USA, is a major shorebird stopover site where, in spring, many thousands of shorebirds undergo rapid mass gain by feeding on the eggs of commercially harvested horseshoe crabs Limulus polyphemus. 2. Environmental factors may cause deviations from the best migration schedule. We used within-year mass gain data from red knot Calidris canutus caught in Delaware Bay between 1998 and 2005 to determine the degree of flexibility individuals have to vary migration speed. 3. Mass gain by birds below 133 g was shown to comprise 15·3% fat (39 kJ g−1), the remainder being lean mass (6 kJ g−1). Above this critical level, fat comprised 83·9% of mass deposition. The rates of energy deposition (kJ d−1) were therefore fundamentally different between the two states but were among the highest ever recorded among vertebrates (5–7 × basic metabolic rate). 4. A total of 36–62% of the variation in observed rates of energy deposition between 1998 and 2002 was explained by a year factor, date and mass at initial capture and interaction terms, such that light-weight birds at the end of May had rates of mass gain or energy deposition two to three times higher than birds of similar mass in mid-May, indicating that birds were attempting to achieve a certain mass by a certain date. In 2003 and 2005, this relationship broke down as a result of lower densities of eggs. 5. Synthesis and application. The maintenance of high densities of crab eggs required for high rates of mass gain in red knot requires severe cuts in, or the complete cessation of, the crab harvest, reduced human and raptor-related disturbance as well as management of beaches to provide sufficient crab-spawning habitat. These findings are widely applicable to other systems where harvesting activities come into conflict with migrating animals and show that certain sections of the population, in this case the long-distance migrants from South America, will be impacted more than short-distance migrants whose physiology may give them access to alternative food resources. [ABSTRACT FROM AUTHOR]

Abstract: This study was carried out in eight stands of wetland woods located in the north-western part of the Iberian Peninsula. The number of sampling sites per stand depended on the physical heterogeneity and area of each stand. Biological data recorded per site included species composition and a list of structural parameters (relative cover in each forest layer, tree height, tree diameter at breast height, number of live and dead trunks and individuals, and morphological adaptations to flooding). Hydro-geomorphologic, geological and climatic variables were also obtained. The floristic data set was subjected to a non-hierarchical cluster analysis and a principal component analysis, which provided an overall image of vegetation grouping based on community composition that only considered perennial species (trees, shrubs, non-annual herbaceous plants and climbers). Three groups of plant communities were distinguished, with an overstorey that was dominated by Betula alba, Salix atrocinerea and Alnus glutinosa, respectively, which presented different environmental drivers. The structural features of each group that was characterised by a different overstorey species were analysed and differences were tested. The number of trunks per individual, number of dead trunks, canopy height and the presence of adaptations to flooding were the structural parameters that best separated the wetland wood groups. Environmental variables were correlated with the ordination axis to analyse community distribution trends and the hydrological regime was found to be the key environmental factor controlling both floristic and structural patterns. [Copyright &y& Elsevier]

Most populations of migrant shorebirds around the world are in serious decline, suggesting that vital condition-dependent rates such as fecundity and annual survival are being affected globally. A striking example is the red knot (Calidris canutus rufa) population wintering in Tierra del Fuego, which undertakes marathon 30,000 km hemispheric migrations annually. In spring, migrant birds forage voraciously on horseshoe crab eggs in Delaware Bay in the eastern USA before departing to breed in Arctic polar deserts. From 1997 to 2002 an increasing proportion of knots failed to reach threshold departure masses of 180-200 g, possibly because of later arrival in the Bay and food shortage from concurrent over-harvesting of crabs. Reduced nutrient storage, especially in late-arriving birds, possibly combined with reduced sizes of intestine and liver during refuelling, had severe fitness consequences for adult survival and recruitment of young in 2000-2002. From 1997 to 2002 known survivors in Delaware Bay were heavier at initial capture than birds never seen again, annual survival of adults decreased by 37% between May 2000 and May 2001, and the number of second-year birds in wintering flocks declined by 47%. Population size in Tierra del Fuego declined alarmingly from 51,000 to 27,000 in 2000-2002, seriously threatening the viability of this subspecies. Demographic modelling predicts imminent endangerment and an increased risk of extinction of the subspecies without urgent risk-averse management.