Species at risk
Monarch butterflies are now considered endangered in the province
Biologist says additions to endangered list part of a troubling trend
The recent addition of 11 new wildlife species to the species at risk list in Nova Scotia is part of a troubling global trend, says Mark Elderkin, an endangered species biologist with the Department of Natural Resources who recently spoke at the New Glasgow library.
The total number of species at risk in Nova Scotia is now at 71.
The species recently added to the list include the bank swallow (endangered); gypsy cuckoo (endangered); monarch butterfly (endangered); tall beakrush (endangered); transverse lady beetle (endangered); evening rose beak (special concern); yellow-banded bumble bee (special concern); black foam lichen (threatened); eastern water fan (threatened); Sable Island sweat bee (threatened) and the wrinkled shingle lichen (threatened).
“It’s a barometer that is telling us our choices need to be reexamined, in terms of pesticide and agricultural use scenarios, and how we think about natural pollinators,” Elderkin said, referencing the fact that two species of bee are now on the list.
“We’re so distanced from the landscape we use to grow food that we don’t think about these insects. Not many people know their names, but there are such integral relationships between our wellbeing and theirs,” he said. “That is the challenge – making the public aware and engaged, to find solutions to these things.”
The department uses a set of criteria, taking a species’ rate of decline over time, as well as variables such as the magnitude of the threats facing a particular species.
According to the Department of Natural Resources species that is vulnerable is at a high risk of endangerment in the wild – on account of characteristics that make it sensitive to human activities or natural events. Species that are threatened are likely to become endangered if limiting factors are not reversed. A species that is that is endangered is at a high risk of extinction in the wild. Elderkin said habitat is often involved in how animals become at risk. The Department of Natural Resources looks to see if there are any physical interventions such as harvesting – or anything toxic, such as pesticide use, that could create a threatening scenario for the habitat of a particular species.
The department categorizes the level of threats to a species and its habitat, tabulating a broad summary of threats, and narrows it down to threats that specifically are the most direct.
Elderkin said accounting for and controlling threats to a particular species is always a complicated matter. Most species have extremely complex and multiple threats, and at different scales. Determining which of those threats are the most urgent adds another layer of complexity to the matter, he noted.
Sometimes, certain threat are as easy to identify, such as looking to see what sort of industries are in a particular area – for example, finding quarry operations in an area where bank swallows nest.
“We look at what might be say, threatening reproduction of the monarch butterfly,” Elderkin said. “Many questions come from that threat analysis, and they all have to be considered in terms of scale… and our ability to effectively provide intervention.”
Elderkin believes the monarch butterfly’s addition to the department’s list will constitute an opportunity to cultivate greater public awareness of the issues facing at risk species.
The recognizable insect’s role as a consumer of milkweed – a product that is toxic to most other animals, is a good example of the kinds of issues at stake and the fact that at risk animals can have a marked effect on other animals and the ecosystem in which they live. “Their whole survival depends on the toxicity of the plants they eat – most birds won’t eat monarch butterflies because of the toxic milkweed they eat. If a dairy animal eats that milkweed the butterflies eat, they can get very sick,” Elderkin explained.
Another area of particular concern for the department entails species that are global endemic populations. These species have a very small range, and constitute isolated populations – such as the Sable Island sweat bee.
Elderkin said that on account of their habitat being so small and isolated, smaller occurrences can have a much more dramatic effect on global endemic species.
“(Sable Island) is the entire world of that bee. The risks for that species are greater because it’s one tiny population, and it’s nowhere else in the world,” Elderkin said. “There are very few species in Canada that are global endemic.”
Natural Resources Minister Margaret Miller described the species on the list as a significant conservation concern. She stated the province will continue to work with public, industry and land stewards to protect those animals and their habitat.
“All of us can help protect these treasured species by becoming better informed, and by taking care when we are out in the forest, wetland or other habitat where they live,” Miller said.