Species at risk

Monarch but­ter­flies are now con­sid­ered en­dan­gered in the prov­ince

The News (New Glasgow) - - FRONT PAGE - BY SAM MACDON­ALD

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.


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