Major highway in India threatens reptiles and amphibians

“Is it the road that crosses the habitat, or does the habitat cross the road?” ask scientists before agreeing that the wrong road at the wrong place is bound to cause various perils for the local wildlife, habitats and ecosystems.

Is it the road that crosses the habitat, or does the habitat cross the road?” ask scientists at Gauhati University (Assam, India) before agreeing that the wrong road at the wrong place is bound to cause various perils for the local wildlife, habitats and ecosystems. Furthermore, some of those effects may take longer than others to identify and confirm.

This is how the research team of doctoral research fellow Somoyita Sur, Dr Prasanta Kumar Saikia and Dr Malabika Kakati Saikia decided to study roadkill along a 64-kilometre-long stretch of one of the major highways in India: the National Highway 715. 

What makes the location a particularly intriguing choice is that it is where the highway passess between the Kaziranga National Park, a UNESCO World Heritage site in Assam and the North Karbi Anglong Wildlife Sanctuary, thus tempting animals to move to and from the floodplains of Kaziranga and the hilly terrain of the Sanctuary to escape the annual floods or – on a daily basis – in search for food and mating partners.

In the beginning, they looked into various groups, including mammals, birds, reptiles, and amphibians, before realising that the death toll amongst frogs, toads, snakes and lizards was indeed tremendous, yet overlooked. Their findings were recently published in the peer-reviewed scholarly journal Nature Conservation.

“To our surprise, the death toll within that 64-kilometre stretch of the highway was indeed dramatic. We estimated that it has been over 6000 animals that have fallen under the wheels of motor vehicles within a single year. Prior to our study, similar research had focused on big charismatic species like the tiger, elephant and rhino, so when we took into account also the smaller animals: frogs, toads, snakes and lizards, the count went through the roof. Thus, we decided to make smaller species the focus of our work,”

comments Sur.

In conclusion, the scientists agree that roads and highways cannot be abandoned or prevented from construction and expansion, as they are crucial in connecting people and transporting goods and necessities. 

“Yet, we can definitely put some effort into designing and constructing them in a scientifically sound, eco-friendly and sustainable manner, so that they don’t become the bane for our ecosystems,”

the team concludes.

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Research article:

Sur S, Saikia PK, Saikia MK (2022) Speed thrills but kills: A case study on seasonal variation in roadkill mortality on National highway 715 (new) in Kaziranga-Karbi Anglong Landscape, Assam, India. In: Santos S, Grilo C, Shilling F, Bhardwaj M, Papp CR (Eds) Linear Infrastructure Networks with Ecological Solutions. Nature Conservation 47: 87-104. https://doi.org/10.3897/natureconservation.47.73036

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Green backyards help increase urban climate resilience: Here is how

New study evaluates the effects of greenery on thermal comfort, biodiversity, carbon storage and social interactions.

Green spaces in cities have a number of positive effects: they’re good for our physical and mental health, they’re good for the environment, and they can even help fight off the effects of climate change.

To explore the impact of additional green structures in cities, Katja Schmidt and Ariane Walz, affiliated with the University of Potsdam, Germany, quantified their effects on different aspects such as thermal comfort, biodiversity, carbon storage and social interaction. Their study, published in the open-access, peer-reviewed journal One Ecosystem, combines knowledge from health research, ecology and socio-ecological research, and shows how the better we know a particular type of ecosystem, the better we can adapt to climate change.

Green residential courtyards in Potsdam. Photo by Jan Michalko, University of Potsdam

Pursuing a multi-method approach that ranged from local climate measurements to habitat and tree mapping, the authors compared four green residential courtyards in Potsdam. The spaces were similarly built, but had different ratios and sizes of features (lawns, flowerbeds, paths, playgrounds and allotments), as well as different tree and shrub population. 

While doing their research, Schmidt and Walz saw how even small differences in the green structure affect the provision of benefits, but one thing was clear: the greener courtyards yielded more benefits. Trees have the vital ability to cool down the environment and increase thermal comfort. Remarkably, the researchers report additional cooling effects of up to 11°C in the greener court yards. This means that residential green structures can prove of great value for human health during summertime heat, when asphalt and buildings make hot days even hotter. Considering the ageing demographic and the likely increase of heatwaves in the area, this is likely to have even greater health implications in the coming years. 

Microclimatic measurements in residential courtyards. Photo by Tobias Hopfgarten, University of Potsdam

Urban green spaces can also be an important factor in carbon storage, as urban soils and trees have the capacity to act as a sink for atmospheric carbon dioxide. The residential yards with more and larger trees, logically, have the power to store more carbon. This is where proper maintenance comes in: when yards are managed sustainably, trees live longer and can store more carbon.

“Considering the trend of increasing quantity and magnitude of extreme weather events and the vulnerability of urban areas, green spaces are known to provide great potential to increase urban climate resilience. Our work highlights the widespread positive effects of additional green structures in residential open spaces, a type of urban green space that is frequently understudied,” points out Dr. Schmidt.

As a conclusion, the researchers point out that if land owners and leaseholders receive incentives to commit to climate adaptation, and neighbourhoods come up with deliberate management strategies, these benefits could be further enhanced, contributing to a more sustainable urban development.

Research article:

Schmidt K, Walz A (2021) Ecosystem-based adaptation to climate change through residential urban green structures: co-benefits to thermal comfort, biodiversity, carbon storage and social interaction. One Ecosystem 6: e65706. https://doi.org/10.3897/oneeco.6.e65706

How quickly do flower strips in cities help the local bees?

Insects rely on a mix of floral resources for survival. Populations of bees, butterflies, and flies are currently rapidly decreasing due to the loss of flower-rich meadows. In order to deal with the widespread loss of fauna, the European Union supports “greening” measures, for example, the creation of flower strips.

A group of scientists from the University of Munich, led by Prof. Susanne S. Renner, has conducted the first quantitative assessment of the speed and distance over which urban flower strips attract wild bees, and published the results of the study in the open-access Journal of Hymenoptera Research.

Flower strips are human-made patches of flowering plants that provide resources for flower-visiting insects and insect- and seed-feeding birds. Previous experiments have proved their conservation value for enhancing biodiversity in agricultural landscapes.

The success of flower strips in maintaining populations of solitary bees depends on the floristic composition, distance from suitable nesting sites, and distance from other habitats maintaining stable populations of bees. To study the attractiveness of the flower strips in urban landscapes, the scientists used an experimental set-up of nine 1,000 sq. meters flower strips recently established in Munich by a local bird conservation agency.

“We identified and counted the bees visiting flowers on each strip and then related these numbers to the total diversity of Munich’s bee fauna and to the diversity at different distances from the strips. Our expectation was that newly planted flower strips would attract a small subset of mostly generalist, non-threatened species and that oligolectic species (species using pollen from a taxonomically restricted set of plants) would be underrepresented compared to the city’s overall species pool,”

shared Prof. Susanne S. Renner.

Bees need time to discover new habitats, but the analysis showed that the city’s wild bees managed to do that in just one year so that the one-year-old flower strips attracted one-third of the 232 species recorded in Munich between 1997 and 2017.

Surprisingly, the flower strips attracted a random subset of Munich’s bee species in terms of pollen specialization. At the same time, as expected, the first-year flower-strip visitors mostly belonged to common, non-threatened species.

The results of the study support that flower strip plantings in cities provide extra support for pollinators and act as an effective conservation measure. The authors therefore strongly recommend the flower strip networks implemented in the upcoming Common Agricultural Policy (CAP) reform in the European Union.

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Original source:

Hofmann MM, Renner SS (2020) One-year-old flower strips already support a quarter of a city’s bee species. Journal of Hymenoptera Research 75: 87-95. https://doi.org/10.3897/jhr.75.47507

Be prepared: Prioritising invasive species for strategic prevention in Durban, South Africa

Durban Harbour, used for both commercial and recreational purposes, is an important hub of human activity. The harbour was found to be an important point of first introduction as well as a site for naturalisation for the three species highlighted in this study.
(Photos by Şerban Procheş /left/ and Carl Munsamy /right/)

While exploring the way alien species invade cities around the world, South African PhD student Ashlyn L. Padayachee (University of KwaZulu-Natal, UKZN) and her supervisors, Serban Proches (UKZN) and John Wilson (SANBI and Stellenbosch University) remember suddenly being stricken.

What they realised was that while cities were gradually starting to prepare for climate change, their responses to invasions were rather reactive. Even though management focused on widespread invasive species, which were currently having the most negative impacts on native biodiversity, the researchers noted that if those decision makers had only targeted the next highly damaging invaders ahead of their arrival, the associated costs would have greatly decreased.

Consequently, the team developed a methodology, based on three key aspects: priority species, points of first introduction and sites of naturalisation, in order to identify the most probable and concerning invasive species for Durban (eThekwini in KwaZulu Natal), a coastal city in South Africa. Furthermore, their work, published in the open-access journal Neobiota provides decision makers from around the world with a new tool, that is easy to use and adjustable to the specificity of different cities.

Firstly, the researchers identified cities with a similar climate to Durban and used existing alien species watch lists, environmental criteria and introduction pathways to identify species, which are not present in South Africa, but are considered of unacceptable risk of invasion. The team continued by figuring out which of those selected species are likely to have pathways facilitating their introduction to the city and developed a climatic suitability model for each. Finally, the scientists linked the climate and pathway information, so that they could identify sites within Durban to be considered as a focus for the contingency planning for particular species.

As a result, the authors identified three alien species as priorities for Durban: Alligator weed (Alternanthera philoxeroides), American bullfrog (Lithobates catesbeianus) and the red imported fire ant (Solenopsis invicta).


River systems are ideal habitats for Alligator weed. River systems adjacent to points of first introduction were identified as important sites of first naturalisation of this species.
(Photo by Şerban Procheş)

In terms of points of introductions, the data highlighted the Durban Harbour, especially for the red imported fire ant. Plant nurseries and garden centres, as well as pet and aquarium shops were also identified as important sites for the three studied species. Additionally, suitable habitats located near the points of introduction, such as river systems and built infrastructure, were found in need of monitoring.


The red imported fire ant is usually found in close proximity to human dwellings, which provide ideal habitats for this species. Built infrastructure, especially those adjacent to the Durban Harbour, was identified as an important site of its naturalisation.
(Photo by Şerban Procheş)

In conclusion, the implementation of prioritisation schemes to consider the three aspects (species, pathways, and sites) allows managers to focus resources on those species which pose a greater risk of invasion and impact.

“This will only ever be one part of a broad range of biosecurity efforts, but it is one where, we believe, we can be prepared,” comment the authors.

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Original source:

Padayachee AL, Proches S, Wilson JRU (2019) Prioritising potential incursions for contingency planning: pathways, species, and sites in Durban (eThekwini), South Africa as an example. NeoBiota 47: 1-21. https://doi.org/10.3897/neobiota.47.31959