Every year, on the first warm rainy night of spring (usually around 55 degrees), wood frogs, spring peepers and mole salamanders (which include several mid-sized, stout-bodied salamander species) begin a mass migration to the vernal pools where they breed. This event is commonly referred to as the "big night." It is impossible to set a calendar appointment for this event, but keep an eye on the temperature in your area and when the mercury rises from the 40s to the 50s, especially if there is a warm week prior to the first rainy warm(ish) night, be on the lookout. If possible don't drive on nights you think may be a potential "big night" to avoid hitting migrating amphibians.
How can you identify a vernal pool? They are typically small (some may be larger) ponds that fill with water for a short time during spring. Most dry up by the end of summer. In some areas, vernal pools may fill after fall rains. These small, temporary ponds may not sound very impressive, but they are critical breeding habitat for amphibians. What makes them so important to amphibian survival is the absence of predators, such as fish, during the egg and larval stages of frogs and salamanders. If you happen upon a vernal pool, look for egg masses and tadpoles as well as fairy shrimp (a tiny crustacean) and other animals that you will only find in a vernal pool in spring. If you're interested in learning more about vernal pools, you can contact local nature organizations, such as Audubon centers to find and explore vernal pools in your community. If you'd like to participate in citizen science programs for mapping and certifying vernal pools, simply do a Google search for vernal pool mapping near you or contact your state university extension office for guidance.
What are threats to vernal pools? Mainly development and adverse effects of habitat alteration. Even though there are rules and buffers in place to protect wetlands and vernal pools, impacts are inevitable. If a pool is protected but not the surrounding woods where amphibians spend the other 11 months of the year, the population will decline. Other factors contributing to vernal pool decline are pollution, water table changes and a warming climate that will dry up pool prematurely.
Vernal pools are a unique habitat and if you have an opportunity to explore one, definitely do it! Always be mindful that there may be amphibians on the move and the area surrounding the pools is also sensitive, so tread lightly!
We are no strangers to invasive species at Naturedigger. Many of our apps highlight invasive plants and/or animals and raise awareness about the damage they can cause if not kept in check. Since this week (2/25 through 3/3) is officially National Invasive Species Week, We are highlighting one of the world's top 100 most invasive species, knotweed. First, here is some basic information about invasive species.
How does an invasive species get transported from its natural environment to one that allows it to thrive and take over?
Typically, plants and animals are brought to the U.S. and Canada accidentally and undetected, but not always.
• Can arrive either with nursery stock unintentionally or as ornamentals (on purpose) which are purchased and prized by gardeners (i.e. giant hogweed)
Aquatic plants and animals:
• Often arrive in the ballast water of large container ships entering our waterways (think zebra mussels). Once they release their water, everything they picked up in their home port is now quite happy living in ours.
• Fishermen often transport fish and plants from waterbody to waterbody unknowingly, so remember to Clean, Drain and Dry your boat and fishing gear before launching into a new waterbody.
• Careless aquarists also help spread aquatic invasive species such as fish, snails and aquatic plants because they often release them into local waterbodies once they are no longer interested in keeping them. This is a huge problem and species such as elodea and goldfish are becoming a huge issue for freshwater ponds and lakes. Always contact your local pet store to drop off any unwanted plants or animals or list them for sale or for free.
Why do so many foreign species take over?
Occasionally when released to a new environment, a plant or animal may either die off quickly due too poor conditions, lack of food, lack of mates or something they require but can't obtain in their new environment. However, quite often they spread or grow out of control primarily due to the absence of whatever kept them in check in their home range. This could include bugs, diseases, climate, soil type and myriad of other things that allow them to grow normally and not expand beyond their normal range.
A perfect example of a plant that has gone unchecked and is exploding across the country is knotweed. This seemingly unstoppable plant blocks wildlife corridors, causes flooding as well as expensive property damage. It can change water chemistry and become a monoculture in areas of sensitive habitat, like river banks. Japanese knotweed is the most commonly recognized of the knotweed species, however, there are four separate species, which includes a hybrid. All knotweed species are aggressive and costly both to homeowners and to open space, wildlife and public park managers.
Below are images of all four species. Check out our Nature Education section on this site for more identification help and download our iOS app, Knotweed! to learn to identify all four species using our Quick ID slides. Also, take a look at the management plan in the More... menu of the app in the event you encounter it on your own property. To ensure you never bring knotweed into your life, always be aware of where your topsoil and mulch come from if you are doing a landscaping project. If you employ a lawn maintenance company, ask them if they are able to identify knotweed before they park on your property or unload any equipment. And NEVER back your car or truck into an area with knotweed, since just a single node from the stem can get stuck in your tire tread and drop onto your lawn starting a new infestations.
Since knotweed will find a way to break apart roads and in some cases the foundation of your home (when growing nearby), it is very important to learn to identify it quickly and take care of it before it becomes a major issue. See structural damage photos below as inspiration to learn to identify knotweed in the early stages before they become a headache and a ten year long management project.
Knotweed structural damage
If you live in the US and experienced the wrath of the recent Polar Vortex, you undoubtedly have cabin fever. Big time. We all do! Just remember that even though it is the middle of winter, poison ivy, poison oak and poison sumac can still dish up a healthy dose of contact dermatitis and leave you very uncomfortable for weeks or longer if you don't catch it in time. Be on the lookout for white berries on stems with an alternate leaf arrangement (leaf scars are not right across from each other). The stems with berries are the female plants and many of the berries are still present on the plants throughout the winter and spring.
Remember to wash your clothes as soon as you get home from your much-needed nature fix, since you can get urushiol oil on your pants or snow pants. The oil will linger on your clothes while sitting in your laundry basket and spread to other articles of clothing, yourself or a family member. Also wash with Dawn dish detergent immediately if you think any part of your skin came in contact with one of these rash plants.
Enjoy your hike and be safe!
For more information download Rash Plants from the App Store!
In a shocking (and awesome) announcement by the Monarch Joint Venture (MJV), eastern monarch populations are up 144% from last year!
If you recently read that monarch populations are down a devastating 86% this year and now you're hearing they are up 144%, don't worry, you aren't losing your mind. If you are unfamiliar with North America's monarch butterfly populations, it's important to note that there are two separate migrating populations in the United States and one mostly nonmigratory population in Florida.
The two distinct migrating populations include one in the far west (west of the Rocky Mountains), and one in the east (east of the Rocky Mountains).
We'll start with the bad news first...
Western Population: This is the population that has declined 86% this year, which couldn't be worse news for an already struggling population.
(Read Naturedigger's earlier blog posts to find out how you can help)
Where do they migrate to and from? The western population overwinters along the coast of California and migrates in early spring to the Rocky mountains, then returns to the California coast in the fall. See the migration map below provided by Monarch Watch.
Now for the good news...
Eastern Population: This is the population that is rebounding (at least this season) and appear regularly in the news due to their dramatic decline over the last 20 years.
Where do they migrate to and from? The eastern population overwinters in Mexico, specifically in the in the oyamel fir forest, which is how the population numbers for the year are determined. In the spring they migrate north from Mexico and fly throughout the United states east of the Rocky Mountains, north toward Canada and east throughout the eastern United States. The last generation then returns back to their wintering grounds in Mexico in the fall. This epic migration is as mysterious as it is truly remarkable.
See the map below provided by Monarch Watch and the chart of population by hectare in Mexico provided by the Monarch Joint Venture.
So what can we attribute this unbelievable increase in eastern monarch populations to? According to the MJV, "Good weather conditions during the breeding season supported the increase, as well as efforts across North America to protect and restore habitats."
The weather is something we obviously have no control over, however, participation in habitat restoration we can all control. Clearly the formula the MJV (and its many partners) is using is working.
Now let's get to work on the western population and see if we can bring those numbers up next year, as well.
Check out the MJV's website links for general information about monarch nectar plants and much more as well as specific information about the eastern migratory population. Visit the Xerces Society for guidance on the western monarch population as well as pollinator plants for your area if you live in the western US.
The Xerces Society Thanksgiving count numbers were just finalized for our North American western monarch population and it's as bad as the initial estimate. According Xerces, we have lost 86% of monarchs within the last year, and they have issued a call to action. This is serious. Click the image below to find out how you can help western monarchs rebound from this devastating decline.
Photo credit: Xerces Society for Invertebrate Conservation
Photo by Naturedigger
If you're a news junkie like most of us living the United States have become, you've undoubtedly run across the numerous articles about the dramatic decrease in our western monarch population in 2018. Our MJV partner, Xerces Society, who conducts the annual Thanksgiving count, released preliminary overwintering monarch numbers in an alarming statement this week which should cause concern among not only the western states where this is occurring, but everywhere, since this unprecedented decline is likely caused by several factors that affect everyone. Below is an excerpt:
"Pesticides, habitat losses and more frequent and severe droughts caused by climate change are believed to be the primary reasons for the decimation of the butterfly population," Xerces says.
Take moment to read the article in its entirety and comment below.
We can all make small changes in our lives such as planting only native plants and not using pesticides in our gardens or on our lawns. Conserving open space in our communities needs to be a top priority or we stand to lose this iconic species and many other beneficial pollinators along with it.