Showing posts with label endangered species. Show all posts
Showing posts with label endangered species. Show all posts

Monday, March 11, 2019

Life isn't all Rainbows and Butterflies...

Guest post by Carolyn Thickett, MSc. Candidate at the University of Toronto-Scarborough

Life isn't all Rainbows and Butterflies...

… especially in an age of extreme habitat loss, chemical pollution, invasions by alien species and climate change. All of these pressures are contributing to the dramatic decline of insects currently being observed all around the world.

In Canada, the general public is responding by trying to contribute their time and knowledge in any way that they can. Citizen Science programs encourage people with little or no previous experience to participate by working with staff from one of the conservation areas in the Greater Toronto Area. These programs are aimed at engaging the general public in conservation efforts for the purpose of education, but with the added benefit of reducing the cost of expensive conservation work.

Many more events are happening out of the public eye, not advertised, even held in secret. I attended one such event this past June, held in an undisclosed location, in Eastern Ontario. This was an invitation-only event, attended by a consortium of people concerned about the status of the Mottled Duskywing Butterfly in Ontario, spearheaded by butterfly enthusiast Jessica Linton.

Mottled Duskywing Butterfly. Photo: Carolyn Thickett


Dr. Gard Otis, a bee and butterfly researcher from the University of Guelph, is unveiling new
information about these specialist butterflies and their unique habitat requirements. The Mottled Duskywing depends on New Jersey Tea (Ceanothus americanus), a plant that is common to alvars as well as sandy soils supporting oak savannas, a critically endangered habitat in Canada. Land management issues related to the preservation and restoration of grassland habitats, such as oak savannas, must then be included in the Mottled Duskywing recovery strategy.

One of those issues is fire suppression, originally put into practice due to the inherent risk to
property and human lives. The suppression of fire over time promotes plant succession, which is the process by which grasslands turn into shrublands, then into thickets and eventually into forests. Succession is detrimental to New Jersey Tea. It is a grassland plant that requires full sun and is unable to compete with the increasing canopy density of a forest. But what if fire wasn’t suppressed? Wouldn’t New Jersey Tea burn too?



As it turns out, New Jersey Tea is not only tolerant of fire, but it produces vigorous growth shortly after a fire disturbance (Throop & Fay, 1999). So, there is a threatened population of butterflies… living in a rare habitat… and scientists are setting it on fire?? Yup. It’s called prescribed burning.

But how do the butterflies survive such a disturbance? Sites are burned in sections, creating a patchwork of habitat with some portions left for conditions required by the butterflies. Some research by Swengel and Swengel (2007) suggests that some permanent unburned areas within the landscape may be important for specialist Lepidopterans, such as the Mottled Duskywing and the Karner Blue Butterfly (Lycaeides melissa samuelis), which is extirpated in Canada. Additionally, fire can provide many benefits which can even outweigh the risks. Recent work by Henderson et al. (2018) shows the short-term positive effect on another grassland butterfly to prescribed fire regimes. The diagrams below illustrate the results of their study and show the positive benefit derived from regular, and even frequent, burns.



Dr. Otis and myself walked transects through specific locations within the landscape, recording the location of each Mottled Duskywing that we encountered, the quantity of New Jersey Tea plants and keeping tally of the totals. Dr. Otis’ study will examine how Mottled Duskywings respond to the prescribed burns by utilizing different portions within the landscape. The next prescribed burn will occur early next spring by property staff, then the butterfly populations will again be assessed and compared with the baseline data.

In addition, staff at the Cambridge Butterfly Conservatory are currently working on determining the caterpillar rearing requirements of a related species, the Wild Indigo Duskywing. At this point they have had success getting females to lay eggs in captivity and rearing the larvae. The knowledge gained with the Wild Indigo Duskywings will be applied to the Mottled Duskywings, working towards reintroduction to one or more sites where they used to occur within the province, perhaps as early as 2020.

The Mottled Duskywing butterfly population we surveyed is the largest in Canada. At the end of the count, we received word that 4 teams of observers recorded 210 butterflies. This was great news for the researchers as the population appears to be stable, although the true population can only be determined through a detailed mark-recapture study which is tentatively being planned for summer 2019.

Mottled Duskywing conservation is gaining momentum… work has already started on habitat recovery and caterpillar rearing protocols. The information gathered and recovery actions taken could have implications for many other native prairie and grassland species. The same can be said for every other count, assessment, or restoration event. Whether you are a researcher or a concerned citizen, get involved. Know that your efforts could have massive implications for biodiversity, you could even SAVE a species from extinction!

To get involved in conservation, visit citizen science.

For more information on Mottled Duskywing butterflies, read the recovery strategy.

References

Fickenscher, J.L., Litvaitis, J.A., Lee, T.D. & Johnson, P.C. Insect responses to invasive shrubs:
Implications to managing thicket habitats in the northeastern United States. Forest Ecology
and Management 322 (complete), 127-135 (2014).

Henderson, Richard A., Meunier, Jed, & Holoubek, Nathan S. Disentangling effects of fire,
habitat, and climate on an endangered prairie-specialist butterfly. Biological Conservation 218
(complete), 41-48 (2018).

Swengel, A. B. & Swengel, S. R. Benefit of permanent non-fire refugia for Lepidoptera
conservation in fire-managed sites. Journal of Insect Conservation 11, 263–279 (2007).

Throop, Heather L. & Fay, Philip A. Effects of fire, browsers and gallers on New Jersey tea
(Ceanothus herbaceous) growth and reproduction. The American Midland Naturalist 141 (1),
51 (1999).

Thursday, November 13, 2014

Giving Turtles a Head Start

*Guest post by Jethro Valido -one of several posts selected from the graduate EES3001 Scientific Literacy course at University of Toronto-Scarborough.


Photo from  Adopt-a-Pond at Toronto Zoo
When I think about turtles, the first things to come to mind are that they are slow and that they’ve been on Earth for forever. So it came to me as a surprise when I found out that most of Ontario’s turtles are actually endangered and at risk of disappearing in Ontario. In fact, seven out of the eight turtle species found in Ontario are threatened
and are in dire need of help in order to maintain populations. The problem with turtles are that they are extremely long-lived (can live up to 70+ years) and that they have a late sexual maturation (20-25 years). This makes it hard for us to study them and pin-point a cause to their decline, especially when action is required immediately.

So what exactly can we do to help their numbers from declining? One way we can help our turtles is through a head-start program. A head-start program is the process in which juveniles (in this case turtle eggs) are raised in captivity until they reach a certain age, and then they are release back into the wild. This is exactly what I am doing at the Toronto zoo; where we are head-starting the Blanding’s turtle.

The Blanding’s Turtle is one of the threatened species of turtles in Ontario. It can be easily identified and differentiated from other native turtles by its yellow throat and jaw. The biggest threats to this species are associated with humans; ranging from habitat loss due to land development, to being hit by cars when trying to cross roads due to habitat fragmentation, to predation from urban wildlife, such as raccoons, coyotes, skunks, etc. Though once numerous, their numbers have drastically declined, and to help restore their numbers, we are implementing a head-start program for this species at the zoo. This will help encourage the young to grow to maturity, where they have a higher success rate at surviving than when juveniles.

Photo from  Adopt-a-Pond at Toronto Zoo
The head-start program starts off with looking for Blanding’s turtle nests in at-risk locations. These locations are areas such as crop fields, where the eggs they would not have a good chance for survival. These eggs are then transported to the Toronto zoo where they are raised in captivity until they are 2 years old. The reason for this is to prevent predation. At birth, the turtles are very small and are easy prey for animals such as raccoons. By raising them until they are 2 in what could be called a “safe haven” for the turtles, they can grow to a sufficient size to deter predation once released. By deterring predation, their chances for survival is increased.  Once released, the turtles are tracked by radio-tracking devices and monitored.

The really interesting part about this all as a research student working at the Toronto zoo, is that there a lot of questions around the idea and process of head-starting. Although head-starting has been successful for sea turtles, its success is unknown for these freshwater turtles we have in Ontario; including Blanding’s turtle. The Toronto zoo is invested in this project long term, especially since the Blanding’s turtle has a late maturation, thus this project will be heavily research-based to understand the effects head-starting has on these turtles and whether the protocols are well-suited for the turtles. Because of this, there is a huge range of flexibility in adjusting or improving protocols and it is really something that can be applied to other turtle species around the world.

Photo from  Adopt-a-Pond at Toronto Zoo
The Adopt-a-Pond Program at the Toronto zoo is heavily involved with this project and they are quite determined to restore our Blanding’s turtle populations. With the release of these two year old turtles, Adopt-a-Pond is as well restoring their habitat; wetlands. Not only will these turtles receive help but they will act as an umbrella species to protect other threatened wetland species as well. Though we are not 100% certain whether head-starting will restore the Blanding’s turtle populations, this project is just a step in aiding declining turtle populations. From this, hopefully we can gain and discover answers to many of the questions concerning its decline, and eventually manage a long-term solution. Though rare today, hopefully one day, I can walk around the Rouge Park and bump into a yellow-throated turtle.



Here are some additional links:
-       Adopt-a-Pond Blog http://adoptapond.wordpress.com/ - Here, you can follow the Adopt-a-Pond team on their blog. They post up plenty of blogs following the status of their turtles (including Blanding’s turtles) and their releases
-       Earth Rangers Blog http://www.earthrangers.org/blog/ - Here, you can follow the Earth Rangers blog (Earth Rangers are in partnership to head-start the Blanding’s turtle). The website is mostly for children but they have posted up head-starting blogs. 

Wednesday, April 14, 2010

Teaching a quoll that cane toads are bad

ResearchBlogging.orgOften, species become endangered because of multiple stressors, with habitat destruction taking the prize as the most egregious. However, often what pushes a species into extinction is not the main driver of endangerment. For example, passenger pigeon numbers were decimated by unabated hunting, but the proximate cause of extinction was likely an inability to thrive in low densities. Yet, seldom is the case where a known single species interaction is the primary cause of engangerment and maybe extinction. The northern quoll, Dasyurus hallucatus, is an endangered marsupial predator in Australia. The current major threat to the northern quoll is the invasion of toxic can toads. Quolls, being predators of small mammals, birds, reptiles and amphibians, readily attacks cane toads, which are toxic to quolls. Quoll populations have disappeared from areas invaded by cane toads, and extinction seems almost inevitable.

Given that the spread of cane toads into the remaining quoll habitats is inevitable, research, led by Stephanie O'donnell in Richard Shine's lab at the University of Sydney and published in the Journal of Applied Ecology, is underway to train quoll's to avoid cane toads. These researchers feed a subset of captive quolls dead toads laced with thiabendazole, a chemical that induces nausea. They then fitted individuals with radio collars and released these toad-smart quolls as well as toad naive ones. Some toad-naive quolls died quickly, after attacking cane toads. Only 58% of male naive quolls survived, while 88% of toad-smart males survived. While females seemed less likely to attack toads, 84% of naive females survived and 94% of toad-smart females survived!

See the video of a toad-smart quoll deciding not to eat a cane toad, its pretty cool.




O’Donnell, S., Webb, J., & Shine, R. (2010). Conditioned taste aversion enhances the survival of an endangered predator imperilled by a toxic invader Journal of Applied Ecology DOI: 10.1111/j.1365-2664.2010.01802.x