A tiger salamander seeks love and parenthood in a restored Delmarva bay habitat by Kevin Stohlgren
Throughout a career in natural resources work, one of the questions I get most often is, “what do you do in the winter?” It is a common perception that there just isn’t much to do when it comes to field biology and conservation in the coldest season. It is true that the urgency caused by blooms and baby animals is less in the winter, but plenty of vital functions in the life histories of our native wildlife happen at this time of year.
For example, young macroinvertebrates survive and thrive in freshwater streams, enjoying less active predators and preparing for a spring and summer frenzy of hatches. The Department of Natural Resources’ staff at the Maryland Biological Stream Survey take advantage of this by conducting macroinvertebrate sampling in March and April, when stream temperatures are still cold and nobody has left the party yet; in other words, they find the most consistent species diversity at the end of winter and very early spring. Many of our native birds are also quite active in winter, like owls, who use the winter months to communicate with potential mates (check out this edition’s article by educator Edwin Guevara for more information, and we suggest the Merlin Bird ID app for helping to identify owl calls). Perhaps most surprisingly, some native amphibians are also very busy in the winter months- like the Endangered eastern tiger salamander (Abystoma tigrinum).
Tiger salamander eggmass by Kevin Stohlgren
Tiger salamander research is nothing new for the Natural Heritage Program; keeping tabs on their populations is part of what we do in an effort to conserve species listed in Maryland as Endangered. In 2009, department biologist Scott Smith wrote an article for the Maryland Natural Resource magazine, offering excellent historical context to this ongoing project and a detailed description of this species’ winter activities.
In 2020, just a few days before pandemic chaos erupted in our human world, DNR scientists cheerfully reported increased population numbers in the winter salamander surveys. Fast forward to 2023 and the cooperative surveys continue, with the addition of some new land management practices. Forested wetland ponds have been intentionally opened up over the past 15+ years by carefully removing individual trees; since 2019, woody vegetation management has accelerated in select habitats. Tiger salamanders require a very specific combination of fish-free wetland conditions. On the Eastern Shore, the temporary pools they inhabit – called vernal pools – usually fill up during fall or winter rains and dry out by summer, creating an environment where predatory fish cannot survive.
Sadly, climate change, unusual storms, and other human impacts can mean these ponds don’t drain or can connect to larger water bodies, inviting fish to stay and feast. As the perfect salamander real estate becomes more and more rare, even the best vernal pools can be altered by natural processes like forest succession. This means trees can take over, shading out sunlight that can make the difference between life and death for young salamanders. Biologist Beth Schlimm now leads a team with the goal of preventing this succession in known tiger salamander habitat, giving these beloved creatures a fighting chance at survival. Redefined land management strategies have also increasingly prevented human impacts that can decimate a local breeding area, like commercial clear-cutting and aggressive logging (see figure below). Dedication to continuing these practices long-term could eventually mean the delisting of this species as Endangered!
What can Maryland residents do to help the eastern tiger salamander? The overarching lesson we’ve learned from decades of combined monitoring and land management is if we enhance existing habitat and protect it in areas they already occur, tiger salamanders will expand and thrive. Just like humans, they need housing options to choose from in order to successfully grow their populations and continue their life cycles. Locally, we can help by advocating for conservation and protection of large interconnected areas of land with vernal pools and forested areas around them, called buffers. Within these protected areas, we can fund and support the practices that science has shown to work. And remember, just like the biologists at the Natural Heritage Program and our beloved eastern tiger salamanders, conservation doesn’t stop in the cold winter months!
Welcome HabiChatters to the 2023 winter issue!
In this issue, Education Ecologist Paula Becker starts us off with a fantastic overview of what is happening in the natural world at this time of year, and then I’ll tell you some of what we’re up to in the Natural Heritage Program. Education Assistant Edwin Guevara writes about some of our favorite winter wildlife, owls and evergreens. And, if our newsletter didn’t fully feed your craving for reading, I’ve included a reading list to inspire and delight. We hope you enjoy and wish you a very Happy New Year from the education team at Wild Acres!
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In this Issue
- In Praise of Dormancy
- Native Plant Profile: Evergreens
- Native Animal Profile: Stealthy (and Cute!) Owls
- A Cozy Winter Reading List for 2023
