Future Restoration Activities Research Articles

Mosaic of biological soil crusts and vascular plants contributes to the spatial heterogeneity of key soil properties at different successional stages of restored inland sand dunes

Abstract Background and aims Inland sand dunes constitute Natura 2000 habitat that has become a priority to ensure biodiversity protection and habitat heterogeneity at the landscape scale; however, without proper management, spontaneous succession leads to overgrowing of trees and thus to habitat degradation. Understanding succession processes, relationships between biotic and abiotic components, and their changes over time after restoration, is the key to proper planning of future restoration activities. The aim was to determine the changes of biological soil crust (BSC), vascular plants and physicochemical parameters of BSC, below-crust, rhizosphere, and bare substrate types at different stages of succession in inland dunes of the Błędowska Desert (Poland). We also analyzed the interplay between these factors to further understand the mechanism of BSC development and recognize driving factors causing changes in the soil environment. Results Our results showed that BSCs contributed to increased organic C, total N, nutrients in soil, and acidification with the succession. The content of inorganic N forms was significantly higher in bare soil compared to below-crust soil. Rhizosphere soil was enriched in organic matter and nutrients, which improves soil conditions within plant patches. Moreover, below-crust soil pH, total N content and water holding capacity drive the patterns of BSC morphological groups and species composition of lichens, bryophytes, and vascular plants. Conclusion Our study shows that spatial structure of the inland dune ecosystem is a mosaic of BSCs and plants that contribute to the spatial heterogeneity of key soil properties. We concluded that it is necessary to consider the matter of BSC in restoration treatments.

Effects of extreme temperatures and recovery potential of Gongolaria barbata from a coastal lagoon in the northern Adriatic Sea: an ex situ approach.

Globally, rising seawater temperatures contribute to the regression of marine macroalgal forests. Along the Istrian coastline (northern Adriatic), an isolated population of Gongolaria barbata persists in a coastal lagoon, representing one of the last marine macroalgal forests in the region. Our objective was to examine the impact of extreme temperatures on the morphology and physiology of G. barbata and test its potential for recovery after simulating marine heatwave (MHW) conditions. We explored the occurrence of marine heatwaves in southern Istria, adjacent to the study area, in addition to extreme temperatures inside the area itself. Subsequently, we performed a thermotolerance experiment, consisting of a stress and recovery phase, in which we exposed G. barbata thalli to four extreme (28, 30, 32 and 34 °C) and one favourable (18 °C) temperature. We monitored morphological and physiological responses. Our findings indicate a significant rise in frequency, duration and intensity of MHWs over decades on the southern Istrian coast. Experimental results show that G. barbata demonstrates potential for both morphological and physiological recovery after exposure to temperatures as high as 32 °C. However, exposure to 34 °C led to thallus decay, with limited ability to regenerate. Our results show that G. barbata has a remarkable resilience to long-term exposure to extreme temperatures ≤32 °C and suggest that short-term exposure to temperatures beyond this, as currently recorded inside the lagoon, do not notably affect the physiology or morphology of local G. barbata. With more MHWs expected in the future, such an adapted population might represent an important donor suitable for future restoration activities along the Istrian coast. These results emphasize the resilience of this unique population, but also warn of the vulnerability of marine macroalgal forests to rising seawater temperatures in rapidly changing climatic conditions.

Assessment of the restoration potential for ecological sustainability in the Xijiang River basin, Southwest China: A comparative analysis of karst and non-karst areas

Vegetation restoration is an eco-friendly strategy for countering land degradation and biodiversity loss. Since 2000–2001, large-scale restoration projects have been performed in Southwest China, with the net primary productivity (NPP) increasing over the past two decades. However, negative ecohydrological impacts, including streamflow decline and soil moisture deficit, have been reported following afforestation. Current understanding of the permissible NPP capacity (NPPcap) and NPP potential (NPPpot) under karst and non-karst areas or planted and natural vegetations constrained by environmental factors remains unclear. Here multiple environmental drivers characterizing the heterogeneous landscape in the Xijiang River Basin (Southwest China) were employed to predict the NPPcap using a random forest model. Results showed that 85% of the area exhibited an increasing trend in NPPcap during 2001–2018. Overall, 3.50% of the area has exceeded the NPPcap, implying an excessive plantation and potential water deficit in these areas. Excluding agriculture activities, urban areas, and water bodies, we found there is room for an average extra 22.85% of NPP enhancement. The NPPpot was spatially imbalanced, with high NPPpot located in the northeast, indicating these areas as a target area for future vegetation restoration. Moreover, the NPPpot reduction in karst areas (1.12 g C m−2 a−1) was more pronounced than in non-karst areas (0.26 g C m−2 a−1), highlighting a stronger negative impact on NPPpot in karst areas. Furthermore, significant NPPpot differences were found between planted vegetation and natural vegetation for both karst and non-karst areas. According to the findings, we identified four separate restoration sub-zones and proposed tailored strategies to guide the implementation of future restoration efforts. Our study highlights restoration potential and where land is available for reforestation but also the urgent need for future restoration activities towards ecosystem sustainability.

Standardized protocol for reproductive phenology monitoring of fucalean algae of the genus Cystoseira s.l. with potential for restoration

Active marine restoration is strongly encouraged to prevent the loss of the valuable habitats formed by Cystoseira sensu lato species, since they enhance biodiversity and preserve ecosystem functions and services. Current restoration interventions are mainly based on recruitment enhancement methods by deploying bags with fertile receptacles in situ or by outplanting juveniles grown ex situ under laboratory conditions. These methods allow the recovery of endangered species avoiding the depletion of the donor populations. In all cases, a priori knowledge of the reproductive phenology and recruitment periods of the species to be restored is essential, since the success of restoration techniques relies on collecting fertile branches and the obtention and survival of recruits. For their collection, identified donor populations characterized by dense Cystoseira s.l. cover should be studied. Specifically, monitoring the reproductive phenology of populations is crucial to detect the period of the year in which they develop mature reproductive structures and to understand how it might be linked to environmental conditions. Then, these general patterns on the reproductive phenology of Cystoseira s.l. species are essential to determine the most suitable time and conditions to plan for the most effective restoration action. Here, we provide a cost-effective and friendly protocol that can be easily and widely implemented for all Cystoseira s.l. species. We pose that this protocol provides a standardized and useful methodology to understand the environmental factors driving the optimal periods for sampling fertile branches across the Mediterranean Sea, and thus it can be an essential tool to plan future restoration actions.

Effects of multiple stressors on recruitment of long‐lived endangered freshwater mussels

Abstract Multiple stressors can affect populations interactively. However, the process by which they affect recruitment remains unclear, especially in long‐lived organisms with complex life cycles. This study explored the bottleneck stages of juvenile recruitment in the endangered freshwater pearl mussel Margaritifera togakushiensis and the interactive effects of nutrients and fine sediments on these stages. The proportion of M. togakushiensis juveniles aged ≤10 years was investigated in 24 rivers from north‐eastern Japan. Margaritifera togakushiensis has a complex life cycle with an obligate parasitic larval stage. Gravid female density, glochidia density (the number of glochidial infections per stream area), and juvenile survival rate, used as indices for adult, parasitic, and post‐parasitic juvenile stages, respectively, were obtained from 11 of these rivers. Twenty‐four population status assessments showed that the proportion of juveniles aged ≤10 years ranged from 0.00 to 0.23, and that they were absent in 12 rivers. Parasitic and post‐parasitic juvenile stages were bottlenecks for recruitment; juvenile survival rates had a stronger positive effect on recruitment in rivers with high glochidia density. Juvenile survival rate was negatively associated with the synergistic effects of nutrients and fine sediments, although factors limiting glochidia density were not identified. These findings suggest that the interaction between nutrients and fine sediments can synergistically reduce the recruitment of M. togakushiensis, indicating an underestimated impact of stressors on mussel recruitment if treated individually. Future mitigation measures should consider both nutrient levels and fine sediments to restore mussel recruitment. These results also emphasize the importance of considering both parasitic and post‐parasitic juvenile stages of mussels to maximize the success of future restoration actions.

Oil exploitation drives environmentally- and trait-mediated diversity of non-native plants in the Yungas forest in Argentina

Anthropogenic disturbances profoundly affect forest ecosystems worldwide. Oil exploitation is one of the major stressors driving the high co-occurrence of different non-native plant species in the Yungas forest of Calilegua National Park, Argentina. Using a dataset of records collected from 2010 to 2020, we evaluated environmental drivers and oil exploitation activity shaping the occurrence and diversity of non-native plant species in 18 study sites.To do so, we first compared species richness and diversity at different levels of anthropogenic disturbance. Then, we used regression models to investigate species-environment relationships. Lastly, a fourth corner analysis was applied to investigate how the interaction between explanatory variables and plant functional traits shapes the occurrence of the studied non-native plant species.We found that oil exploitation activities promoted the diversity of non-native plants in the protected area. Presence of the three most widespread non-native plant species was influenced by the topographic slope and organic matter content. The fourth corner analysis further showed that the positive interaction between plant N-fixation capacity with either close proximity to oil boreholes, a low organic matter content or a high coverage of herbs positively affected the presence of non-native plant species.To our knowledge, this is the first time that trait-environment relationships under a gradient of anthropogenic disturbance were investigated to explain the occurrence and diversity of non-native plant species. Given that abundant non-native plant species have partially overlapping niches in the Yungas transition forests, it is advisable that future restoration actions focus on groups of non-native plants rather than single species. Additionally, non-native plant species of concern, which are able to successfully establish in both disturbed and undisturbed areas require adapted eradication measures.

Coastal landforms and fetch influence shoreline restoration effectiveness

Coastal shorelines are a key interface between terrestrial and aquatic ecosystems and are vital for human livelihood. As a result, shorelines have experienced substantial human modifications worldwide. Shoreline “hardening” – the construction of armor including seawalls, bulkheads, or rip-rap – is a common modification that has substantial negative ecological effects. Currently, restoration involving the removal of armor and replacement with “living” shorelines is becoming an established practice. Still, the ecological response to armor removal is oftentimes unpredictable and site-specific. We hypothesized that the confluence of larger-scale geophysical features might strongly influence ecological restoration outcomes at particular locations. To measure the effectiveness of armor removal in the context of broad-scale geophysical features across the Salish Sea, WA, USA, we studied 26 paired restored and natural reference beaches of the same shoretype (feeder bluff, accretion shoreform, or pocket beach), as well as corresponding fetch, sub-basin, and percent of shoreline sediment drift cell armored. Sites were restored for an average of six years. We gauged restoration effectiveness based on levels of five ecological response variables: beach wrack (percent, depth), logs (count, width), sediments (percent sand), vegetation (percent overhanging, count of fallen trees), and insects (density, taxa richness). We found that armor removal often restored these variables to natural levels, but that restoration response was dependent on geophysical features such as shoretype and fetch. Natural beaches did have higher measurements of overhanging vegetation, fallen trees, and insect taxa richness, as these features likely take time to mature at restored beaches. Feeder bluffs had a higher proportion of surface sand and number of fallen trees than other shoretypes, coinciding with the erosion of bluff material, whereas natural pocket beaches within bordering rocky headlands had higher insect densities. Sites with a large fetch had higher input of deposited wrack and logs, whereas sites with a small fetch had higher input from localized terrestrial sources – fallen trees and eroding sand. By incorporating the effectiveness of restoration with landscape features such as shoretype and fetch, we can more effectively plan for future restoration actions and better predict their outcomes.

The Use of Unoccupied Aerial Systems (UASs) for Quantifying Shallow Coral Reef Restoration Success in Belize

There is a growing need for improved techniques to monitor coral reef restoration as these ecosystems and the goods and services they provide continue to decline under threats of anthropogenic activity and climate change. Given the difficulty of fine-scale requirements to monitor the survival and spread of outplanted branching coral fragments, Unoccupied Aerial Systems (UASs) provide an ideal platform to spatially document and quantitatively track growth patterns on shallow reef systems. We present findings from monitoring coral reef restoration combining UAS data with object-oriented segmentation techniques and open-source GIS analysis to quantify the areal extent of species-specific coverage across ~one hectare of shallow fringing reef over a one-year period (2019–2020) in Laughing Bird Caye National Park, southern Belize. The results demonstrate the detection of coral cover changes for three species (Acropora cervicornis, Acropora palmata, and Acropora prolifera) outplanted around the caye since 2006, with overall target coral species cover changing from 2142.58 to 2400.64 square meters from 2019 to 2020. Local ecological knowledge gathered from restoration practitioners was used to validate classified taxa of interest within the imagery collected. Our methods offer a monitoring approach that provides insight into coral growth patterns at a fine scale to better inform adaptive management practices for future restoration actions both within the park and at other reef replenishment target sites.

The Mediterranean bioconstructor Lithophyllum stictiforme shows adaptability to future warming

Understanding how coralline algae may acclimatize to ocean warming is important to understand their survival over the coming century. Taking advantage of natural differences in temperature conditions between coastal areas in Sardinia (Italy) and between depths, the responses in terms of biological traits to warming of the crustose coralline alga Lithophyllum stictiforme, a key bioconstructor of coralligenous reefs in the Mediterranean, were evaluated in the field by two innovative transplant experiments where translocated specimens were used as controls. Results of the first experiment (algae cross transplanted between a cold and a warm site at two depths, 23 and 34 m) showed that the marginal growth of the alga and production of conceptacles were higher in the cold site, regardless of the treatment (transplant and translocation) and depth. However, growth in thickness in algae transferred from the cold to the warm site was higher at 34 m of depth, where they had a better performance than the local (translocated) algae. Results of the second experiment (algae transplanted from 34 m to 15 m of depth under different light irradiance manipulations) evidenced that the increase in temperature of +4°C was tolerated by thalli transplanted at 15 m, but that thallus growth and conceptacles production was negatively affected by the higher light irradiance. These results suggest an overall good adaptability of L. stictiforme under warmer conditions, even those due to thermocline deepening. Overall, these results encourage consideration of the use of transplants of this bioconstructor in future restoration actions of coralligenous habitats.

Using relative return‐on‐effort scoring to evaluate a novel coral nursery in Malaysia

Coral reefs in Malaysia have been degraded by environmental and anthropogenic stressors, and enthusiasm for coral propagation aimed at site restoration is rapidly growing as a local management tool. However, coral propagation activities in the region are in their infancy and little data currently exists to guide and inform effective practices. We therefore established the first multi‐taxa coral tree nursery (6 species and 300 fragments) in Malaysia and tracked survival and growth to determine the relative return‐on‐effort (RRE) over an approximately 14‐month monitoring period. We observed differences in growth and survival among six coral species and were successful at benchmarking results against coral restoration operations globally and in the East Asian Seas region. Major findings include (1) overall ranges in species level survivorship of 34–94% and specific growth rate of 0.14–0.29%/day, leading to variable RRE scores among species, (2) variable growth rates among coral species based on seasonal changes in environmental conditions, (3) similar RRE scores to other nursery locations worldwide, which suggests effective practice, and (4) calculation of RRE scores for species not previously reported in nursery culture (Acropora florida, A. hoeksemai, and Echinopora horrida). Ultimately, our study supports previous findings that RRE is an effective technique for comparing coral nursery performance and offers valuable insight to guide future restoration activities in Malaysia.

The effect of past defaunation on ranges, niches, and future biodiversity forecasts.

Humans have reshaped the distribution of biodiversity across the globe, extirpating species from regions otherwise suitable and restricting populations to a subset of their original ranges. Here, we ask if anthropogenic range contractions since the Late Pleistocene led to an under-representation of the realized niches for megafauna, an emblematic group of taxa often targeted for restoration actions. Using reconstructions of past geographic distributions (i.e., natural ranges) for 146 extant terrestrial large-bodied (>44kg) mammals, we estimate their climatic niches as if they had retained their original distributions and evaluate their observed niche dynamics. We found that range contractions led to a sizeable under-representation of the realized niches of several species (i.e., niche unfilling). For 29species, more than 10% of the environmental space once seen in their natural ranges has been lost due to anthropogenic activity, with at least 12species undergoing reductions of more than 50% of their realized niches. Eighteen species may now be confined to low-suitability locations, where fitness and abundance are likely diminished; we consider these taxa 'climatic refugees'. For those species, conservation strategies supported by current ranges risk being misguided if current, suboptimal habitats are considered baseline for future restoration actions. Because most climate-based biodiversity forecasts rely exclusively on current occurrence records, we went on to test the effect of neglecting historical information on estimates of species' potential distribution - as a proxy of sensitivity to climate change. We found that niche unfilling driven by past range contraction leads to an overestimation of sensitivity to future climatic change, resulting in 50% higher rates of global extinction, and underestimating the potential for megafauna conservation and restoration under future climate change. In conclusion, range contractions since the Late Pleistocene have also left imprints on megafauna realized climatic niches. Therefore, niche truncation driven by defaunation can directly affect climate and habitat-based conservation strategies.

Estimationof Biomass and Carbon Sequestration by Non-Destructive Method in Dry Deciduous Forest of Shivpuri, Madhya Pradesh, India

The study aims to assess the plant biomass and carbon storage potential of the forests of Shivpuri, Madhya Pradesh, India. The study was carried out in Satanwada Range in Shivpuri Forest Division. A total of 96 quadrats of 10×10 m2 were laid. The non-destructive algometric method was used to estimate carbon sequestration. The results show that Acacia catechu (202 individuals/ha) dominated the forest, followed by Anogeissus pendula (90 individuals/ha). The total biomass of the forest was estimated to be 34.72±0.41t/ha, with Boswellia serrata (7.943t) recording the highest. The minimum biomass was recorded for Grewia sp (0.06t). The highest carbon content was found in B. serrata (3.97t; 25 individuals) followed by A. Catechu (2.92t; 195 individuals). Although A. catechu was dominant in the area, due to its lower girth class and young age, the net carbon storage was less than that of B. serrata. It was found that plots with higher carbon stock had higher species richness than plots composed of single species. Therefore, plantations of mixed native species should be preferred for future restoration activities as they are more efficient in sequestrating carbon than monoculture plantations.

Structure, composition and carbon stocks of woody plant community in assisted and unassisted ecological succession in a Tamaulipan thornscrub, Mexico

BackgroundEcological restoration is a process that helps the recovery of an ecosystem that has been degraded, damaged or destroyed. The success of restoration actions depend on the understanding of the processes, mechanisms and factors that guide vegetation dynamics. The restoration of plant communities can be made by unassisted (passive restoration, where the community recover by itself) and assisted (active restoration) ecological succession. It is imperative to know the scope of both types of activities to guide future restoration actions by evaluating the properties and functioning of the intervened communities.MethodsVariance analysis of the carbon (C) stocks, basal area, canopy area, Shannon–Weaver index values, specific richness and abundance of three Tamaulipan thornscrub communities (assisted natural succession area, unassisted natural succession area and control area) was performed. Furthermore, a similarity analysis between the sampling areas using the floristic composition (abundance) was performed.ResultsIn total, 11 families, 17 genera and 20 species of vascular plants were registered. The richness of species and abundance ranked as follows per area: assisted ecological natural succession > control > unassisted ecological natural succession. The species composition between sampling areas showed a low number of common species between plant communities.ConclusionsThe values of species richness, diversity, abundance, basal area, and canopy area of the assisted natural succession vegetal community was statistical similar to the control plan community. The values of C stocks showed that assisted ecological succession could recover not only structure and composition attributes but also this key ecosystem property.

Contaminants and heavy metals along the mangrove area of Dongzhai Harbor, China: distribution and assessment

In recent decades, higher-place shrimp ponds are prevalent in coastal areas of developing countries. However, shrimp aquaculture has a growing negative impact on mangrove wetland ecosystems. Mangroves located in Dongzhai harbor are under threat continuously of this commercialization. Therefore, a comprehensive analysis of contaminants and heavy metals is necessary for Dongzhai harbor, considering the mangrove area was declined and ecological services offered to the coastal communities with an insight for future restoration activities. In this study, pond effluents (Total Nitrogen (TN), Ammonia Nitrogen (AN), Total phosphorus (TP), Chemical Oxygen Demond (COD)) and heavy metals (Cd, Cu, Pb, Zn) were monitored in Dongzhai harbor yearly between 2013 and 2017. The results showed that the contents of Cd, Cu, Pb, and Zn were far lower than the standards. However, the main contaminants were organic matter and nitrogen. Maximum values of COD and TN were 26.10 mg·L−1 and 1.34 mg·L−1, respectively in 2017. Single factor index, Nemerow's pollution index, and Trophic level index revealed that the heavily polluted areas were Tashi and Sanjiang town.

Comparing the potential reproductive phenology between restored areas and native tropical forest fragments in Southeastern Brazil

Plant phenology is rarely considered when selecting species used in restoration actions. However, considering the potential flowering and fruiting phenologies of species is a key point to: (1) evaluate the capacity of restoration actions in reestablishing ecological interactions (pollination and seed dispersal) and ecosystem functions (early germination and plant establishment to reduce soil erosion); (2) determine which species are most suitable to the target site, and (3) identify when and where locally adapted seeds can be harvested and purchased. Here, we evaluate the potential reproductive phenology of species occurring in restored and forest fragments in Southeastern Brazil. We asked whether flowering and fruiting phenological patterns differed among type areas. For such, we compared 14 restored areas and 18 nearby forest fragments and compiled phenological data from the literature for 267 species (84% of species sampled). Despite their low floristic similarity, restored and forest fragments showed close similarity of general potential flowering and fruiting periods year‐round, peaking in the dry‐to‐rainy season. There were only slight differences in seasonality of two out of the eight parameters evaluated. Nonzoochorous species' fruiting was seasonal, while zoochorous species fruiting onset occurred year‐round but was slightly seasonal in forest fragments. Comparing potential phenological patterns between restored and forest fragments using a compilation from secondary sources are unprecedented in Brazil at this scale. Our results highlight that applying phenological information, even from literature, is essential to improve the science and practice of future restoration actions, enhancing the likelihood of successful restoration of ecosystem functions and species interactions.

Assessing vertical structure of an endemic forest in succession using terrestrial laser scanning (TLS). Case study: Guadalupe Island

Endemic species comprise 16% of the floral species on Guadalupe Island, including three arboreal species. Almost 96% of the forest coverage was lost due to impacts related to feral goats and wildfires. To date, goats have been eradicated and the restoration of the native vegetation communities is underway. The purpose of this study was to develop a 3D Structural Classification Method (3D-SCM) using Terrestrial Laser Scanner (TLS) for mapping the vertical structure of the forest and to automatically characterize its physical attributes. Several TLS scans were performed in July 2016 to assess this recovery, particularly the succession progression. The 3D-SCM used the Forest Condition Classification (FCC) based on radiometric intensity and height values, and the Individual Shape Index (ISI) based on geometry and intensity parameters. It was designed to classify vegetation by stratum using a trial-and-error model to semi-automatically identify impacted areas and succession. The 3D-SCM was able to differentiate the vegetation strata by each forest community at the stand level with a precision of 93% as well as the tree structure parts (stem, branches, and leaves) with a precision of 97%, it also fits the best characteristic shape for the Guadalupe cypress (decagon) and for the pine (droplet). The resulting 3D-SCM provide precise physical specifications, demonstrates a high correlation R2 = 0.949 for (Diameter Breast Height) DBH, R2 = 0.974 for the crown and R2 = 0.97 for heights between maximum laser pulse of tree heights and crowns with respect to field measurements. Mapping 3D vertical forest measurements are important for quantifying the success of management practices and to assist future restoration actions, as it will allow quantification of forest dynamics and carbon sequestration on this island.

Spatiotemporal seed transfer zones as an efficient restoration strategy in response to climate change

AbstractRestoration of wild plant populations in a changing environment is not a simple task, and it becomes increasingly complex and challenging in the context of climate change. In the present study, a spatiotemporal approach was used to delimit provisional seed transfer zones (STZs), for restoration activities involving two wild perennial grasses in Argentina. Ecogeographical land characterization maps were built specifically for the two species of Trichloris genus for the present bioclimatic conditions to define the different STZs; then, they were projected for two future climate scenarios (2050 and 2070). This allowed us to identify populations occurring in cells that underwent changes in ecogeographical categories, potential future beneficiaries of germplasm, and populations that could be used as corresponding source populations under the present conditions. Finally, the conservation status of populations was surveyed and a germplasm collection for future restoration activities was proposed. For the 2050 scenario, for Trichloris crinita, 32 potential beneficiary populations belonging to nine changing categories were identified, whereas for Trichloris pluriflora, four changing categories determined seven beneficiary populations. The number of changing categories and, consequently, the beneficiary populations increased in the 2070 scenario in both species. Several potential seed source populations are already stored in Argentine germplasm banks, but there is little representation of potential beneficiary populations. Spatial locations of still non‐conserved populations, both seed sources and beneficiaries, were prioritized for future germplasm collecting missions. This novel approach used for Trichloris spp. can also be adopted for other species for collection and/or restoration purposes in the light of climate change.

Linking demographic transitions to population dynamics in a fluctuating environment

Recruitment has been linked to decreases in the ratio of age-specific mortality (M′) to mass-specific growth (G′), and year-class strength may be predicted by the age when M′/G′ = 1. Hydrological stress adversely affects these parameters for species inhabiting floodplains; however, the relationship between M′ and G′ in hydrologically variable environments is poorly understood. We evaluated age-specific mortality for six species from a 20-year time series and growth curves from otolith length-at-age data. We assessed the effect of hydrology on the transitional age (age M′/G′ = 1) at 21 sites representing a hydrological gradient. Disturbance intensity influenced age-specific mortality but had no effect on mass-specific growth. The transitional age was inversely correlated with annual density, but weakly associated with population biomass. Hydrological disturbance shifted the transitional age to older ages, reducing recruitment overall. We demonstrated that the M′/G′ transition was affected adversely by hydrological stress and can be applied to a diverse group of taxa. Growth, survivorship, and the transitional age should be evaluated to improve population modelling efforts used to predict the influence of future restoration actions.

Evidence for historical grizzly bear occurrence in the North Cascades, USA

The North Cascades ecosystem of north-central Washington State (USA) and southern British Columbia, Canada, has been identified as 1 of 6 recovery zones for grizzly bears (Ursus arctos) that were at one time distributed across a nearly continuous range of western North America. The current small number of grizzly bears, along with an apparent scarcity of historical observations, obfuscates the extent to which the mountain range and its surrounding lowlands previously supported grizzly bears. We reviewed and synthesized what is currently known about the historical distribution of grizzly bears in and around the North Cascades to better inform possible future restoration actions. Archeological, ethnographic, and incidental evidence confirm the prehistoric and historic presence of grizzly bears in the ecosystem and surrounding lowlands. Successful implementation of grizzly bear restoration and management in the North Cascades is dependent in part on the perception that they are an integral component of the ecosystem's historical benchmark. Education and outreach efforts that focus on the influence of human perceptions and correcting misinformation about the history of bears in the ecosystem and their interactions with humans may improve long-term restoration success in the North Cascades.

Utilization of multiple microbial tools to evaluate efficacy of restoration strategies to improve recreational water quality at a Lake Michigan Beach (Racine, WI)

Hydro-meteorological conditions facilitate transport of fecal indicator bacteria (FIB) to the nearshore environment, affecting recreational water quality. North Beach (Racine, Wisconsin, United States), is an exemplar public beach site along Lake Michigan, where precipitation-mediated surface runoff, wave encroachment, stormwater and tributary outflow were demonstrated to contribute to beach advisories. Multiple restoration actions, including installation of a stormwater retention wetland, were successfully deployed to improve recreational water quality. Implementation of molecular methods (e.g. human microbial source tracking markers and Escherichia coli (E. coli) qPCR) assisted in identifying potential pollution sources and improving public health response time. However, periodic water quality failures still occur. As local beach managers reassess restoration measures in response to climatic changes, use of expanded microbial methods (including bacterial community profiling) may contribute to a better understanding of these dynamic environments. In this 2-year study (2015 and 2019), nearshore/offshore Lake Michigan, stormwater, and tributary samples were collected to determine if, 1) the constructed wetland (~50 m from the shoreline) continued to provide stormwater separation/retention and 2) mixing between onshore sources, Root River and Lake Michigan, was increasing due to rising precipitation/lake levels. Monthly rainfall totals were 1.5× higher in 2019 than 2015, coinciding with a 0.63 m lake-level rise. The prevalence of more intense, onshore winds also increased, facilitating interaction between potential reservoirs of FIB with nearshore water through wind driven waves and lake intrusion, e.g. beach sands and the adjacent Root River. While a strong relationship existed between wet weather wetland and North Beach nearshore E. coli concentrations (all sites), bacterial communities were strikingly different. Conversely, bacterial community overlap existed between the Root River mouth and nearshore/offshore sites. These results suggest the constructed wetland can accommodate the climate-related changes observed in this study. Future restoration activities could be directed towards upstream tributary sources in order to minimize microbial contaminants entering Lake Michigan.