A rapid survey of herpetofaunal diversity in Nijhum Dwip National Park, Bangladesh

The ecological effects of habitat use by herpetofaunal species vary widely and recognizing relative habitat value will help to improve conservation theory and practice in a particular landscape. To understand how different habitat uses influence diversity in riparian landscapes, we studied reptile and amphibian assemblages across major habitats (agricultural land, forest, human habitation, and waterbodies) in Nijhum Dwip National Park, Bangladesh. A total of 35 herpetofaunal species were found; among them, 17 were directly observed and 18 were reported from a questionnaire survey. Among the observed species, the Asian Common Toad Duttaphrynus melanostictus was the most commonly seen (relative abundance 0.32). We found that forest habitat contained a greater diversity of herpetofauna than other habitats followed by agricultural land, human habitation, and waterbodies. We also found 8 habitat specialist species and 9 generalist species in this study. Our results show that different habitats support different species assemblages in Nijhum Dwip National Park, signifying the importance of diversified habitats for the herpetofaunal population. Understanding this importance is crucial for identifying matrix environments that can complement the forest habitats of sensitive as well as specialist herpetofaunal species.

Distribution and habitat use intensity of the Neotropical Otter (Lontra longicaudis) in a Colombian hydroelectric dam

Introduction: The Neotropical Otter, Lontra longicaudis, is a semi-aquatic mammal that ranges from Mexico to Argentina inhabiting near-pristine watercourses, but also human-dominated aquatic and riparian landscapes. Objective: We assessed the distribution and habitat use frequency of L. longicaudis in La Miel I hydroelectric power dam and its influence area in the Department of Caldas, Colombia. Methods: We carried out diurnal surveys across standardized transects between 2014 and 2018 looking for records (sightings, faeces, tracks, and dens) that indicate the presence of the species. Each yearly survey was done during 12 consecutive days over three seasonal sampling periods assessing the upstream, reservoir, and downstream waterscape areas. Results: We sampled a total of 875 km in a five-year period across the three main waterscape areas (upstream -103 km, reservoir -582 km, and downstream -190 km) registering a total of 1 496 records. Faeces were the most common record (~ 95 %) across the whole study area followed by sightings, dens (1.7 % each), and tracks (1.3 %). Spatial distribution analyses suggest that L. longicaudis prefers dwelling upstream watercourses (hot spots areas; Gi Z-score = 4.46, p < 0.001) and in a lesser extent, areas around the water reservoir (cold spot areas; Gi Z-score = -2.69, p = 0.007). Signs of otters were also recorded at downstream area, but these records were non-significant within the analysis (Gi Z-score = -0.11, p = 0.48), suggesting L. longicaudis uses this area opportunistically. Cluster and outlier analysis showed that even though L. longicaudis was commonly found upstream and in the reservoir area, only some specific sectors (Moro, La Miel and Tasajos rivers) had high (LMI Z-score = 5.63, p = 0.001) and low (LMI Z-score = 2.12, p = 0.001) clusters. Conclusions: The upstream waterscape area is key for the survival of L. longicaudis in this regulated system, likely providing enough shelter and food for the species to carry out living activities and have resident populations. In contrast, downstream areas require specific attention to understand in a better way the effects of caused by the dam on the species dynamics, also defining management strategies that avoid population fragmentation and movement reduction.

Evaluating the recreation potential of the national park “Valdayskiy” (Novgorodskaya Oblast, Russia)

The National Park “Valdayskiy” (the Park) was established to preserve the unique lake-forest complex of the Valday upland and to create conditions for the development of organized recreation on this territory. Incomparable beautiful views of different landscapes attracthere thousands of tourists from various Russian regions.The greater number of them prefers lakeshores for camping,so special attention in the research was paid tothe studyofriparian and shallow water vegetation of lakesin zones with different recreation pressureto establish the patterns of vegetation digression.The materials of our observations are supplemented with data on the attendance of tourist sites collected by the Park staff.The region recreation capacities were studied on the base of bioclimatic indices (Bodman’s indices and subjective temperature).It was revealed that only for the period of 1 month (mid-July to mid-August), there is a massive influx of tourists and intensive use of recreation sites on the lakeshores.This leads to degradation of riparian forest and meadow vegetation; destruction of the protective (buffer) zone of aquatic vegetation, erosion of the banks near camps, pollution of shallow water by sewage and garbage. Thus, irregular recreation pressure on water bodies leads to local degradation of natural complexes and eventually to lowering the aesthetic value of riparian landscapes. But such factors as humid (moderate) continental climate with a prolonged cold winter and high relative air humidity throughout the year reduce the period of a strong recreation pressure, and the complicated accessibility of many lakeshores reduce the negative impact of recreation and delay the destruction of natural vegetation. Evaluation of the bioclimatic indices allows Valday to be attributed to regions with a lack of thermal resources, it is preferable to develop here dynamic types of recreation activities practically all over the year. For soft recreation activity the Valday upland are available with limitation from 7 to 8 months in a year and without limitation nearly 1 month in a year. For nature conservation in the Park it is necessary to organize monitoring of lakeshore’s complexes, control of recreation use, determine pressure of tourist traffic, normalizing and differentiating this pressure by the types of possible use and conservation regime.

Lidar-based approaches for estimating solar insolation in heavily forested streams

Methods to quantify solar insolation in riparian landscapes are needed due to the importance of stream temperature to aquatic biota. We have tested three lidar predictors using two approaches developed for other applications of estimating solar insolation from airborne lidar using field data collected in a heavily forested narrow stream in western Oregon, USA. We show that a raster methodology based on the light penetration index (LPI) and a synthetic hemispherical photograph approach both accurately predict solar insolation, explaining more than 73 % of the variability observed in pyranometers placed in the stream channel. We apply the LPI-based model to predict solar insolation for an entire riparian system and demonstrate that no field-based calibration is necessary to produce an unbiased prediction of solar insolation using airborne lidar alone.

Lidar-based modelling approaches for estimating solar insolation in heavily forested streams

Methods to quantify solar insolation in riparian landscapes are needed due to the importance of stream temperature to aquatic biota. We have tested two approaches developed for other applications of estimating solar insolation from airborne lidar using field data collected in a heavily forested narrow stream in western Oregon, USA. We show that a raster methodology based on the light penetration index (LPI) and a synthetic hemispherical photograph approach both accurately predict solar insolation, explaining more than 73 % or the variability observed in pyranometers placed in the stream channel. We apply the LPI based model to predict solar insolation for an entire riparian system, and demonstrate that no field-based calibration is necessary to produce unbiased prediction of solar insolation using airborne lidar alone.