Historical, contemporary, and future perspectives on a coupled social-ecological system in a changing world: Canada’s historic Rideau Canal

Anthropogenic waterways and canal systems have been part of the cultural and natural landscape for thousands for years. As of the late 20th century, more than 63,000-km of canals exist worldwide as transport routes for navigation, many with barriers (e.g., locks, dams) that fragment the system and decrease connectivity. Fragmentation alone can have negative implications for freshwater biodiversity; by isolating populations and communities, other human-mediated disturbances associated with canals like poor water quality and invasive species can exacerbate these negative effects. As such, the capacity of these interconnected freshwater systems to support biodiversity is continuously degrading at a global level. One critical, highly complex issue that unites canals worldwide is the challenge of governing these systems in a holistic, unified way to both protect biodiversity and preserve historical elements. Managing historic canals involves multiple objectives across many agencies and stakeholders, often with different or conflicting objectives. Here, we use the Rideau Canal, a UNESCO World Heritage Site and National Historic Site of Canada, as a case study to demonstrate the importance of considering canals as social-ecological systems for effective and efficient governance. Historic canals are integrated systems of both humans (social) and the environment (ecological), linked by mutual feedbacks and coevolution, and must be managed as such to achieve conservation goals while maintaining commemorative integrity. We discuss the history of the Rideau Canal and its current governance, biodiversity in the waterway, different threats and issues (user conflicts, aquatic pollution, shoreline development, water management, species at risk, and invasive species), and conclude by outlining ways to address the challenges of managing it as a coupled social-ecological system. We present different research needs and opportunities that would enable better management, though above all, we propose a shift from the current governance structure – which at best can be considered “patchwork” – to a coordinated, multi-scalar and multi-stakeholder governance regime such that the Rideau Canal can be maintained for its historical integrity without compromising biodiversity conservation. Given that canals are now pervasive worldwide, this article is not only topical to the Rideau Canal, but also to other waterways in Canada and beyond.

Lovesick : a short documentary film investigating the changing environment and landscape of a small Canadian lake

The short documentary film, Lovesick, explores the changing environment and landscape of a small Canadian lake through the testimonies of the people who live on its shores. Lovesick Lake is one of the smallest bodies of water along the Trent-Severn canal system – a waterway that connects Lake Huron to Lake Ontario. What once was a prosperous region used by Canada’s First Nations people for hunting and fishing, is now a popular location for summer cottages and resorts. Over the last 60 years, shoreline development has increased exponentially while the health of the lake and surrounding land has declined as a result. Now, the lake and local communities face an uncertain future as new vacation developments are being proposed. The film asks: At what cost does Canada’s cottage country come? Lovesick is a response to the materialistic thinking of Canadians and the land that many people take for granted. It aims to enlighten viewers in the hopes that they begin to question the space they occupy and encourage them to respect the delicate balance between nature and humankind. While cottage country is primarily an Ontario lifestyle, Lovesick is a microcosm that aims to shed light on development of natural areas all over North America – and the detrimental effects development can have on the ecosystem.

Lovesick : a short documentary film investigating the changing environment and landscape of a small Canadian lake

The short documentary film, Lovesick, explores the changing environment and landscape of a small Canadian lake through the testimonies of the people who live on its shores. Lovesick Lake is one of the smallest bodies of water along the Trent-Severn canal system – a waterway that connects Lake Huron to Lake Ontario. What once was a prosperous region used by Canada’s First Nations people for hunting and fishing, is now a popular location for summer cottages and resorts. Over the last 60 years, shoreline development has increased exponentially while the health of the lake and surrounding land has declined as a result. Now, the lake and local communities face an uncertain future as new vacation developments are being proposed. The film asks: At what cost does Canada’s cottage country come? Lovesick is a response to the materialistic thinking of Canadians and the land that many people take for granted. It aims to enlighten viewers in the hopes that they begin to question the space they occupy and encourage them to respect the delicate balance between nature and humankind. While cottage country is primarily an Ontario lifestyle, Lovesick is a microcosm that aims to shed light on development of natural areas all over North America – and the detrimental effects development can have on the ecosystem.

Coronary artery lumen complexity as a new marker for refractory symptoms in patients with vasospastic angina

Refractory angina is an independent predictor of adverse events in patients with vasospastic angina (VSA). The aim of this study was to investigate the relationship between coronary lumen complexity and refractory symptoms in patients with VSA. Seventeen patients with VSA underwent optical coherence tomography. The patients were divided into the refractory VSA group (n = 9) and the stable VSA group (n = 8). A shoreline development index was used to assess the coronary artery lumen complexity. Shear stress was estimated using a computational fluid dynamics model. No difference was observed in the baseline characteristics between the two groups. The refractory VSA group showed the higher shoreline development index (refractory VSA 1.042 [1.017–1.188] vs stable VSA 1.003 [1.006–1.025], p = 0.036), and higher maximum medial thickness (refractory VSA 184 ± 17 μm vs stable VSA 148 ± 31 μm, p = 0.017), and higher maximum shear stress (refractory VSA 14.5 [12.1–18.8] Pa vs stable VSA 5.6 [3.0–10.5] Pa, p = 0.003). The shoreline development index positively correlates with shear stress (R2 = 0.46, P = 0.004). Increased medial thickness of the coronary arteries provokes lumen complexity and high shear stress, which might cause refractory symptoms in patients with VSA. The shoreline index could serve as a marker for irritability of the medial layer of coronary arteries and symptoms.

MAIN STAGES AND REGULARITIES OF COAST FORMATION OF LARGE PLAIN RESERVOIRS

The main stages of the reservoir coast formation and their typological characteristics are considered on the base of the analysis of long-term monitoring studies of the Dnieper reservoirs coast dynamics, as well as generalization of published materials on other large plain reservoirs. It is shown that the common scheme of periodization of the shoreline development manifested itself only in the two stages: abrasion and abrasion-accumulative leveling, and therefore it is premature to claim the general stabilization of the coast formation process. The conventionality of the dynamic equilibrium stage for the coast of reservoirs and the growing role of coastal currents and associated sediment flows and dynamic coast systems are noted. The current state of the coasts of large plain reservoirs is estimated as the beginning of the stabilization phase on the coasts with sufficient sand materials. On the coasts composed of loess, clay or loams the processes of intensive transformation are continued. The analysis of the direction of development of the coastal zone showed three stages of change of shore profile and plan: intensive formation, stabilization and the final stage of attenuation according to the leading factors. Active accumulation means the transition to the stage of abrasion-accumulative leveling, and the emergence of dynamic coast systems and activation of coastal sediment flows means the transition to the dismemberment of the shoreline by accumulative forms. The main regularities of development of coast formation processes – heredity, direction, inertia and variability are analyzed. The heredity means that the geographical and geological conditions which developed before the filling of the reservoir are played the leading role in these processes. The direction of development is associated with an increase of the erosion base and its consequence – the leveling of the coastal zone relief. The orientation of the general process of coast formation to achieve a state of dynamic equilibrium includes stages of inertia and variability. Inertial states are the certain periods when a certain set of factors and conditions and corresponding to them type of coast prevails. Variability is a change in factors and conditions, as a result of which new types of shores or fluctuations in the characteristics of the coastal zone (movement of shoals and dynamic coastal systems, seasonal changes in shore profiles) are formed.

Tapelių ežero morfometrija ir baseino fizinės geografinės ypatybės / Morphometry of Lake Tapeliai and Physicalgeographical Characteristics of its Catchment

Depth measurements of Lake Tapeliai (located in Vilnius, Lithuania) were taken in February 2019. At the same time, the shoreline of the lake was revised. Measurements were made from ice in 767 spots. Depth measurement accuracy up to 0,05 m, accuracy of spot coordinates and water surface elevation measurement using GNSS device Topcon Hiper SR up to 1–2 cm. Later, a detailed (1 x 1 m) digital lake bottom model (DEM) was developed, a bathymetric plan of the lake was created, the main morphometric features were calculated, the boundaries and area of the lake catchment were adjusted, and the physi cal-geographical characteristics of the lake and its catchment were examined based on various data. Morphometric features of Lake Tapeliai measured and calculated in 2019 are as follows: coordinates of mean center 54.774378, 25.4468 (WGS), water surface elevation 136.48 m (in Height System LAS07 of Lithuania), surface area 13.14 ha, shoreline length 1689 m, maximum length 687 m, maximum width 295 m, mean width 191 m, shoreline development 1.31, maximum depth 9.45, mean depth 4.36, volume 573.8 thousands m3, mean width of littoral zone 17,4 m, catchment area (including the lake itself) 2,93 km2. Lake Tapeliai catchment is located in the moraine and limnoglacial plains of Vilija, it is characterized by a rather diverse relief, which consists of a section of Tapeliai glacial tunnel valley, limnoglacial and fliuvioglacial plains, aeolian landforms and moraine hills. Average annual precipitation is ~686 mm. Significant portion (45 %) of the annual precipitation replenishes the lake, mostly through groundwater discharge. Water residence time in the Lake Tapeliai is 0.63 years. Lake Tapeliai covers 4.5 % of the catchment area. Forests cover as much as 79.4 % of the catchment area, pine forests predominate (82.3 %). Built-up areas occupy 11.3 % of the catchment area. The predominantly sandy soils in the catchment area result in abundant groundwater inseeping, which is reflected in the springs found at the bottom of the lake. Abundant groundwater inseeping also reduces lake water level fluctuations, whose estimated amplitude from June 2018 to May 2020 reached just 21 cm. Keywords: Tapeliai Landscape Reserve, Tapeliai, Lake, Vilnius, Lithuania, bathymetric chart, morphometry.

Tropical Cyclone Impacts on Headland Protected Bay

The response of headland protected beaches to storm events is complex and strongly site dependent. In this study, we investigated the response of several headland protected beaches in Noosa, Australia to a tropical cyclone event. Pre and post topographical surveys of all beaches were completed using both pole-mounted RTK-GNSS and structure-from-motion (SfM)-derived elevation models from survey-grade drone imagery to assess sediment volume differentials. Coastal imaging was used to assess shoreline development and identify coastal features while a nearshore wave model (SWAN) was used to project waves into the study site from a regional wave buoy. Obliquely orientated swells drive currents along the headland with sediment being eroded from exposed sites and deposited at a protected site. Elevated sea-levels were shown to be a strong force-multiplier for relatively small significant wave heights, with 10,000 m3 of sediment eroded from a 700 m long beach in 36 h. The SWAN model was adequately calibrated for significant wave height, but refraction of swell around the headland was under-represented by an average of 16.48 degrees. This research has coastal management implications for beaches where development restricts natural shoreline retreat and elevated sea states are likely to become more common.

Aperiodic embayed sandy beach rotation and erosion-risk exposure on a hyper-muddy wave-exposed coast

<p><span>The 1500 km-long wave-exposed coast of the Guianas, South America, is characterized at any time by up to 20+ large distinct mud banks with suspended mud concentrations of up to 1000 g/l migrating from the Amazon delta to the Orinoco delta under the influence of wave-driven longshore transport. Banks can be up to 60 km-long, strongly dissipate waves, and are separated alongshore by ‘inter-bank’ sectors of similar length. The latter are affected by shoreward propagation of much less dissipated waves that can generate rapid muddy shoreline erosion and reworking of beaches and cheniers formed from sand supplied by rivers draining the crystalline rocks of the Guiana Shield.</span></p><p><span>About 500 km northwest of the mouths of the Amazon, the pervasive mud and its effects on the nearshore wave regime determine, for the embayed, headland-bound beaches in French Guiana, outcomes that are important  from a long-term management perspective. These beaches have come under urban pressures and assure recreational and ecological functions such as provision of nesting sites for marine turtles. The sand-mud interactions, processes of sand segregation from mud, sediment transport modes, and morphodynamics associated with these beaches over timescales ranging from weeks to several decades, were analyzed from aerial photographs, satellite images, aerial photogrammetry, and field experiments. The longer bay beaches are exposed to longshore transport when mud is temporarily scarce (inter-bank phases), and subject in parts to overwash. During inter-bank phases, ‘normal’ westward sand transport along these beaches is generated by waves from E to NE, but is counter-balanced during bank phases by eastward drift at the leading edge of a bank as waves are refracted over the bank. This counter-drift prevails at a ‘mobile’ rotation front that moves with the bank’s leading edge migrating at rates of 1 to 2.5 km a year. As the bank passes, it further shelters beaches from wave reworking, with eventual re-exposure to waves and ‘normal’ drift following complete mud-bank passage. In the context of the ‘closed’ sand budget of these beaches, headlands spatially constrain sand mobility, and the unique mode of rotation induced by mud-bank refraction of waves plays an important role by counter-balancing unidirectional longshore transport that could otherwise result in permanent deprivation of updrift beach sectors of sand. Due to variability in bank-migration rates and spacing, normal drift and counter-drift may prevail, respectively, over periods exceeding two years but of unknown duration. The variability of this time frame of rotation poses a challenge to the implementation of set-back lines necessary to avoid the impingement of urbanization and sea-front activities on the long-term (>decadal) bandwidth of beach affected by rotation, which involves aperiodic and variable erosion and accretion in different parts of the beach. In this context of aperiodic beach rotation, prediction of mud-bank migration rates downdrift of the Amazon and of the imminent arrival of a mud bank, coupled with the firm implementation of shoreline development setback lines, are necessary to mitigate risks from erosion and overwash events.    </span></p>

Spatio-temporal variation of zooplankton community structure in tropical urban waterbodies along trophic and urban gradients

The ecological impacts of urbanization and eutrophication on zooplankton communities in urban waterbodies have recently gained wide interest. Study findings vary across species and urban waterbodies. How the development of such changes affects the variation of biotic assemblages has only been explored to a limited extent in tropical urban lakes.Spatial and temporal variations of zooplankton community structure in 11 urban waterbodies in the Klang Valley, Malaysia were investigated along trophic and urbanization gradients. Zooplankton and water quality samples were collected three times, between May and November 2017, from two different locations in each lake. All three main zooplankton groups (rotifera, copepoda, and cladocera) were recorded from the study areas throughout the sampling period. The zooplankton community structure, particularly with regard to rotifers and cladocerans, varied between lakes and seasons. Zooplankton diversity does not vary with lake size or distance from the city center but does vary with shoreline development index and urbanization impacts. The zooplankton populations were dominated by rotifers, mainly Brachionus angularis at all study sites during the study period followed by copepods and cladocerans. The total density of zooplankton was significantly highest (p < 0.05) in the hypereutrophic lakes and during the dry season. Zooplankton diversity and rotifer species richness were negatively correlated with total phosphorus (TP). Diversity increased with urbanization and shoreline development, with rotifers as a potential bioindicator of trophic state in urban tropical lakes, due to their close relationship with TP.

Bromine as indicator of source of lacustrine sedimentary organic matter in paleolimnological studies

Bromine (Br) to organic matter (OM) concentration ratio is studied in lake sediment sequences to provide information on environmental changes modifying OM production. The sequences studied were extracted from shallow lakes Morenito, El Trébol, Escondido, and Portezuelo; and deep lakes Futalaufquen, Moreno, and Traful (North Patagonia Andean range). Lake Morenito, a former Lake Moreno bay until its closure in AD 1960, showed a decrease in Br:OM ratios from 1.38 to 0.74 after lake closure, associated with an increase of primary autochthonous productivity attributable to the development of submerged and emerging macrophytes. Sedimentary sequences from Lakes Escondido, Portezuelo, and El Trébol (with large participation of macrophytes in primary productivity), and from Lakes Moreno, Futalaufquen, and Traful (with little development of littoral macrophytes), showed Br:OM ratios consistent with the Lake Morenito pattern. Consistently, the morphometric parameters mean depth and shoreline development correlate with Br:OM ratios. Therefore, Br:OM ratios can be associated with the composition of primary autochthonous productivity, with values of about 0.7 associated to significant macrophyte contributions, and higher values associated with more pelagic contributions. Accordingly, Br:OM variations along a sedimentary sequence can be associated with modifications on the composition of the primary autochthonous productivity of the water body, providing information on environmental changes.