When I was a child, it was an annual family tradition to participate in an Easter egg hunt in my aunt and uncle's back yard, where dyed eggs were stashed among the landscaping. It's been more than 20 years since my sisters and cousins and I competed for chocolate prizes, and I have rarely rekindled those fond memories, until today when ESF con bio undergrad Tom Maigret and I undertook egg mass surveys among the newly constructed Heiberg pools. I am amazed and ecstatic at what we found.
Before I report our numbers, let me confess that I have maintained a worry about the vulnerability of my dissertation research to the cooperation of animals that we know exist in decent numbers across the landscape, but may be fickle by taking a year off from reproductive activities if the weather is uncooperative (which there were suggestions might be the case with this late and, at times, dry spring), or by entirely ignoring the newly constructed pools, instead preferring their pre-existing oviposition sites. My worry is gone.
Recall that within the pre-existing ponds within the 24-hexagon landscape, 60 wood frog egg masses were observed in both 2009 and 2010. In contrast, 4 spotted salamander egg masses were observed in 2009, and 165 masses in 2010. I have not yet surveyed these pre-existing habitats, but among the 39 constructed pools we counted 131 wood frog and 34 spotted salamander egg masses! There are masses in all hexagons except for the single pool in Hexagon 14, and nine pools lacked egg masses of either species. Wood frog egg masses were observed in 29 pools, and ten pools contained spotted salamander egg masses. Only a single pool contained just spotted salamander egg masses. As Jim Curatolo told me in a conversation last week, in his experience, wood frogs colonize new pools more quickly than spotted salamanders. This may be due to one or a number of factors, such as their relatively greater vagility, or perhaps their social advantage of vocal communication. A single male wood frog that finds a new pool and commences calling to draw in females may also attract other males in the vicinity. Silent salamanders have no comparable ability to exhibit mob mentality. Also, it is possible that philopatry is more pronounced in spotted salamanders relative to wood frogs. Finally, population trend differences in the two species may see the wood frog population surging, while spotted salamander population is static or declining, or less spotteds are emerging to breed this year after their banner year in 2010.
This begs the question: from where did all these wood frogs come?! Is there indeed a population surge occurring? Or is there a carrying capacity for egg masses according to the size and number of available aquatic habitats? While bigger ponds do have a tendency to have more egg masses, it is unknown how this effect occurs: do density effects in the aquatic habitat actually dictate the number of females that return upon maturing, or do adults exercise choice in avoiding aquatic habitats with many masses when there are other options available that will be less crowded for their offspring? In cases where options do not exist, it is hard to imagine animals foregoing breeding if only crowded conditions are available, either waiting for better, less crowded conditions the next year, or even better, for USC to augment the amount of habitat available!
It will be very interesting to see what is the pattern in the pre-existing pools, which I hope I can survey on Monday....
Jim Arrigoni, SUNY-ESF
Sunday, April 24, 2011
Thursday, April 14, 2011
At long last...
Temperatures in the 80s on Monday finally vanquished this seemingly never-ending winter, liberating almost all of the pools of ice. And despite the failure of forecasted thunderstorms to materilize, the amphibians responded throughout Heiberg Forest. After visiting each of the pools on Tuesday 12 April, I'm very pleased to report that wood frogs were observed lurking in the majority of Hexagon pools, and they have deposited egg masses in seven of them. No spotted salamander egg masses have yet been observed, but I think they are forthcoming; nocturnal visits revealed their presence in two of the Hexagon pools, as well as a few pools with spermatophores.
In the Microarray, wood frogs and spermatophores were observed in a few pools in both the field and forest, and a single wood frog egg mass in Pool #17 in the field. But Pool #30 seems to be the place to be: five wood frog and four spotted salamnder egg masses. This pool also was popular with breeding toads shortly after it was constructed last spring. It is large (5 m diameter), shallow (25 cm deep), and did NOT receive an organic topsoil layer. I wonder whether these factors actually matter, or whether Pool #30 is simply the fashionable place to be? Given that calling is still ongoing amidst drenching rains last night and today, and oviposition in pre-existing pools as of yesterday was far less than observed last year, my hunch is that there are many more egg masses to be distributed. Stay tuned....
-Jim Arrigoni, SUNY-ESF
In the Microarray, wood frogs and spermatophores were observed in a few pools in both the field and forest, and a single wood frog egg mass in Pool #17 in the field. But Pool #30 seems to be the place to be: five wood frog and four spotted salamnder egg masses. This pool also was popular with breeding toads shortly after it was constructed last spring. It is large (5 m diameter), shallow (25 cm deep), and did NOT receive an organic topsoil layer. I wonder whether these factors actually matter, or whether Pool #30 is simply the fashionable place to be? Given that calling is still ongoing amidst drenching rains last night and today, and oviposition in pre-existing pools as of yesterday was far less than observed last year, my hunch is that there are many more egg masses to be distributed. Stay tuned....
-Jim Arrigoni, SUNY-ESF
 |
| Microarray Pool 30 on 12 April 2011 |
Sunday, April 10, 2011
I repeat, it's still winter at Heiberg
I visited all 71 pools on Saturday the 9th, and observed quite a bit of variation in terms of hospitability for amorous amphibians. Some pools were entirely encased in ice and snow:
Whereas others looked absolutely inviting:
The majority of pools were largely covered with ice, but with a small areas of open water. Aside from last year's green frog tadpoles observed in a handful of pools, there was no sign of breeding activity in any of the pools: no egg masses, no spermatophores. This was also the case in a few of the pre-existing pools in the hexagon landscape that have historically been popular oviposition sites, so apparently the breeding season has yet to get underway anywhere at Heiberg. In contrast, large numbers of spotted and Jefferson salamanders and wood frogs were observed on the night of 4 March at the amphibian hotspot Labrador Hollow, which is about 3 km to the northeast, but ~150 m lower in elevation. Stay tuned, spring has to be nearing....
Jim Arrigoni, SUNY-ESF
Jim Arrigoni, SUNY-ESF
Friday, April 1, 2011
It's still winter at Heiberg
-Jim Arrigoni, SUNY-ESF
Tuesday, February 22, 2011
Some papers about pond building for amphibians
Dr. Luke Shoo and a group of amphibian conservation biologists recently published a paper titled "Engineering a future for amphibians under climate change" in the Forum section of the Journal of Applied Ecology. The paper does not present new research, but instead proposes habitat management recommendations for conserving amphibians under conditions of rapidly changing climate. Given that they apply to "amphibians" in the broadest sense, the recommendations are very general. They also entail a rather active level of habitat management, as alluded to by "engineering" in the title.
Among the recommendations is a category of "enhancement and restoration of breeding sites," which, of course, is major component of the rationale for the USC/ESF Vernal Pool Restoration Project. They give a brief summary and assessment of previous efforts to construct or restore amphibian breeding sites, and a few general considerations to improve success. In particular, I was pleased to discover a paper in the journal Hydrobiologia titled "Restoring ponds for amphibians: a success story." The European authors report on an ambitious pool construction and restoration effort in Estonia on behalf of imperiled spadefoot toads and crested newts. Their approach, results, and recommendations are especially relevant to us because of their emphases on building clusters of diverse ponds, and in their explicit consideration of terrestrial habitat conditions.
I agree that such active habitat management recommendations can be helpful in mitigating effects of climate change, but I also suggest that some of them are appropriate for mitigating the more traditional threats to amphibian populations such as habitat loss, emerging infectious diseases, and invasive species. It is surprising that, for the time being, there is such a small number of case studies and success stories in the published literature...
Jim Arrigoni, SUNY ESF
Among the recommendations is a category of "enhancement and restoration of breeding sites," which, of course, is major component of the rationale for the USC/ESF Vernal Pool Restoration Project. They give a brief summary and assessment of previous efforts to construct or restore amphibian breeding sites, and a few general considerations to improve success. In particular, I was pleased to discover a paper in the journal Hydrobiologia titled "Restoring ponds for amphibians: a success story." The European authors report on an ambitious pool construction and restoration effort in Estonia on behalf of imperiled spadefoot toads and crested newts. Their approach, results, and recommendations are especially relevant to us because of their emphases on building clusters of diverse ponds, and in their explicit consideration of terrestrial habitat conditions.
I agree that such active habitat management recommendations can be helpful in mitigating effects of climate change, but I also suggest that some of them are appropriate for mitigating the more traditional threats to amphibian populations such as habitat loss, emerging infectious diseases, and invasive species. It is surprising that, for the time being, there is such a small number of case studies and success stories in the published literature...
Jim Arrigoni, SUNY ESF
Wednesday, December 22, 2010
Congratulations, Meredith!
Meredith Atwood was awarded one of four "Best Poster" awards at last month's Student Conference on Conservation Science at the American Museum of Natural History. Meredith has been working at Heiberg Forest with with ESF professors James Gibbs and Kim Schulz to elucidate the role of various forms of leaf litter and soil substrates on wood frog tadpole growth and development. See her winning poster by clicking here.
-Jim Arrigoni, SUNY ESF
-Jim Arrigoni, SUNY ESF
Wednesday, December 15, 2010
Unexpected ecological function of smaller, ephemeral pools
A recent paper published in the journal Ecology adds to the evidence that bigger is not always preferable when it comes to wetlands, and also illustrates the importance of understanding the intricate details of natural history in complex ecological systems:
Altermatt F, Ebert D. 2010. Populations in small, ephemeral habitat patches may drive dynamics in a Daphnia magna metapopulation. Ecology 91: 2975-2982.
Daphnia are miniscule crustaceans that typically comprise a substantial fraction of the zooplankton in lentic freshwater systems throughout the world. They are a vital component of larval spotted salamander diet, particularly early in their development (see Joseph Freda's 1983 paper in Journal of Herpetology [vol. 17, pp. 177-179], "Diet of larval Ambystoma maculatum in New Jersey"). Daphnia are notable in that they employ multiple modes of reproduction, depending on their circumstances. When environmental conditions are favorable, females reproduce parthenogenetically -- they essentially clone themselves, which results in the production eggs that hatch into females. However, when environmental conditions take a turn for the worse (e.g., drawdown in a vernal pool), males develop from some of the eggs, and instead of reproducing asexually, females produce eggs that require fertilization, but are also encased in a hard structure that is resistant to drought and adverse conditions. This is called an ephippium. After adverse conditions have passed, and under appropriate conditions (e.g., inundation of a dry vernal pool basin), ephippia hatch with an endowment of increased and novel genetic variability that is otherwise constrained under stable, favorable conditions and parthenogenetic reproduction.
In addition to allowing Daphnia to persist through unfavorable conditions, it turns out that ephippia are well-suited as a dispersal mechanism since they are easily transported by wind, especially when they coat the basin of a dry pool. Thus, in the context of metapopulations, it is easy to comprehend the importance of smaller and more ephemeral pools as sources for colonizing new habitats and introducing new genotypes into established populations, as shown by Altermatt and Ebert. Larger and more permanent pools tend to sustain themselves nicely, but they do less in the way of interacting demographically or genetically with other pools. This contrasts with an assumption common to many metapopulation models in which bigger patches with larger populations tend to be the sources for dispersing individuals.
The authors admit that there is little in the way of conservation concern for Daphnia magna, which is not rare nor is the species perceived to be negatively affected by limits to dispersal or genetic impoverishment. So far as I know this is the case for our Daphnia spp. as well. Given the unique reproductive modes of Daphnia, the extent to which this pattern can be generalized to other taxa may be limited, although the authors suggest similar dynamics may be found under environmental conditions that negatively affect local survival but benefit dispersal. But I liked this paper because it bolsters the argument that a pool can still have substantial ecological value even if it is tiny and temporary and not churning out amphibian metamorphs.
-Jim Arrigoni, SUNY-ESF
Altermatt F, Ebert D. 2010. Populations in small, ephemeral habitat patches may drive dynamics in a Daphnia magna metapopulation. Ecology 91: 2975-2982.
Daphnia are miniscule crustaceans that typically comprise a substantial fraction of the zooplankton in lentic freshwater systems throughout the world. They are a vital component of larval spotted salamander diet, particularly early in their development (see Joseph Freda's 1983 paper in Journal of Herpetology [vol. 17, pp. 177-179], "Diet of larval Ambystoma maculatum in New Jersey"). Daphnia are notable in that they employ multiple modes of reproduction, depending on their circumstances. When environmental conditions are favorable, females reproduce parthenogenetically -- they essentially clone themselves, which results in the production eggs that hatch into females. However, when environmental conditions take a turn for the worse (e.g., drawdown in a vernal pool), males develop from some of the eggs, and instead of reproducing asexually, females produce eggs that require fertilization, but are also encased in a hard structure that is resistant to drought and adverse conditions. This is called an ephippium. After adverse conditions have passed, and under appropriate conditions (e.g., inundation of a dry vernal pool basin), ephippia hatch with an endowment of increased and novel genetic variability that is otherwise constrained under stable, favorable conditions and parthenogenetic reproduction.
In addition to allowing Daphnia to persist through unfavorable conditions, it turns out that ephippia are well-suited as a dispersal mechanism since they are easily transported by wind, especially when they coat the basin of a dry pool. Thus, in the context of metapopulations, it is easy to comprehend the importance of smaller and more ephemeral pools as sources for colonizing new habitats and introducing new genotypes into established populations, as shown by Altermatt and Ebert. Larger and more permanent pools tend to sustain themselves nicely, but they do less in the way of interacting demographically or genetically with other pools. This contrasts with an assumption common to many metapopulation models in which bigger patches with larger populations tend to be the sources for dispersing individuals.
The authors admit that there is little in the way of conservation concern for Daphnia magna, which is not rare nor is the species perceived to be negatively affected by limits to dispersal or genetic impoverishment. So far as I know this is the case for our Daphnia spp. as well. Given the unique reproductive modes of Daphnia, the extent to which this pattern can be generalized to other taxa may be limited, although the authors suggest similar dynamics may be found under environmental conditions that negatively affect local survival but benefit dispersal. But I liked this paper because it bolsters the argument that a pool can still have substantial ecological value even if it is tiny and temporary and not churning out amphibian metamorphs.
-Jim Arrigoni, SUNY-ESF
Tuesday, October 19, 2010
What comes first - the alga or the egg?
Typically not long after learning about the incredible amphibian migrations to vernal pools in early spring, budding naturalists observe the egg masses of spotted salamanders and wood frogs taking on a dark green color. This is due to the growth of an alga, Oophila amblystomatis, we are told, which has colonized egg membranes and provides oxygen to the amphibian embryos while taking advantage of nitrogenous wastes. This tale of symbiosis adds another level of complexity to the saga of life in a vernal pool.
But it turns out the complexity might be profoundly greater. Dr. Ryan Kerney at Dalhousie University has reported algae within the embryonic cells of spotted salamanders; this discovery, if substantiated, would constitute the first known instance of an endosymbiotic relationship between a photosynthetic organism and a vertebrate. I eagerly await Dr. Kerney's formal publication, but in the meantime the news article spurred James Gibbs and me to consider what we might observe in any egg masses oviposited in the Heiberg pools this spring. Will algae "colonize" egg masses in the new pools, or would they require the assistance of dispersal vectors over varying periods of time? Digging through the literature on O. amblystomatis proved to be an unsatisfying experience, and an example of how conjecture can transform into widespread beliefs...
Although H. Orr is credited as the first to observe algae in spotted salamander egg membranes in an 1888 publication (widely cited but difficult to locate), it turns out that the alga species in question has never been formally described! Perry Gilbert in a 1942 paper describes how the name Oophila amblystomatis was informally adopted by F. D. Lambert ~30 years prior when distributing specimens to other researchers. Gilbert, at least, helps identification matters by providing extensive verbal descriptions, photographs, and illustrations of various forms of the alga, including non-motile and quadriflagellated forms. Gilbert also described experiments that strongly suggested that the pond water, not the parent, was the source provisioning algae to newly oviposited spotted salamander eggs. These results were corroborated by John Gatz with eggs of spotted salamanders, wood frogs, and Jefferson salamanders in a 1958 Journal of Herpetology note (7:137-138). Oddly, he cites an abstract from the 1969 Internation Botanical Congress by P. Biebel when offering the genus Chlamydomonas as a synonym for Oophila, but I cannot discern from the vague abstract how this is justified.
Additional key observations made by both Gilbert and Gatz are that among "several hundred" and "over a thousand" (respectively) spotted salamander egg masses observed in nature, each researcher recalled only a single instance of an egg mass lacking algae late in its development; the symbiosis appears to be nearly, but not completely, ubiquitous. Gilbert speculated that the egg mass lacking algae was located in an old stream bed, and so perhaps algae had been flushed from the system.
The failure of both Gilbert and Gatz to find algae within the reproductive tracts of female salamanders is in contrast to Kerney who supposedly found algae within adult salamander oviducts. This raises the possibility of vertical transmission of the symbiont, and that the salamanders themselves could be the vector bringing O. amblystomatis to novel habitats.
I wrote an email to Dr. Kerney last week to ask how he was dealing with the taxonomic impediments, and if he had any ecological insights regarding the colonization of O. ablystomatis in novel aquatic habitats such as the newly constructed pools at Heiberg. He replied that he has phylogenetic data that places "[their] local Oophila amblystomatis" in the Order Chlamydomonadales. Unfortunately, his research team lacks the resources to undertake more comprehensive phylogeographic analysis, but he speculated that a diversity of algal symbiont types could be associated with different salamanders. He added that it did not appear similar to any especially common northeastern species. In addition, Dr. Kerney confirmed that despite the strong evidence that O. amblystomatis is present in pond water and quickly colonizes newly deposited amphibian eggs, it has never been observed in a free-living state. He expressed a hunch that both vertical and horizontal algal acquisition might be at work, but resolving this experimentally has not been, nor will be, an easy task.
So, given some degree of cooperation by (or manipulation of!) reproductive spotted salamanders and wood frogs, we are poised to make some potentially interesting observations in our experimental system regarding the ecology of O. amblystomatis, with implications for the restoration of populations of amphibian species that enjoy the benefits of association with this ill-known alga(e?). James, Kim and I are in the initial phases of brainstorming experimental approaches to discerning vectors or reservoirs of O. amblystomatis. I wonder if any of the USC folks in the field have observed the tell-tale green egg masses in newly constructed pools down south, and within what kind of timeframes following construction?
This is to say nothing of the recently reported radical endosymbiosis, or what physiological titans spotted salamanders might become if they did not whisk themselves underground the first chance they get after metamorphosing....
Jim Arrigoni, SUNY-ESF
But it turns out the complexity might be profoundly greater. Dr. Ryan Kerney at Dalhousie University has reported algae within the embryonic cells of spotted salamanders; this discovery, if substantiated, would constitute the first known instance of an endosymbiotic relationship between a photosynthetic organism and a vertebrate. I eagerly await Dr. Kerney's formal publication, but in the meantime the news article spurred James Gibbs and me to consider what we might observe in any egg masses oviposited in the Heiberg pools this spring. Will algae "colonize" egg masses in the new pools, or would they require the assistance of dispersal vectors over varying periods of time? Digging through the literature on O. amblystomatis proved to be an unsatisfying experience, and an example of how conjecture can transform into widespread beliefs...
Although H. Orr is credited as the first to observe algae in spotted salamander egg membranes in an 1888 publication (widely cited but difficult to locate), it turns out that the alga species in question has never been formally described! Perry Gilbert in a 1942 paper describes how the name Oophila amblystomatis was informally adopted by F. D. Lambert ~30 years prior when distributing specimens to other researchers. Gilbert, at least, helps identification matters by providing extensive verbal descriptions, photographs, and illustrations of various forms of the alga, including non-motile and quadriflagellated forms. Gilbert also described experiments that strongly suggested that the pond water, not the parent, was the source provisioning algae to newly oviposited spotted salamander eggs. These results were corroborated by John Gatz with eggs of spotted salamanders, wood frogs, and Jefferson salamanders in a 1958 Journal of Herpetology note (7:137-138). Oddly, he cites an abstract from the 1969 Internation Botanical Congress by P. Biebel when offering the genus Chlamydomonas as a synonym for Oophila, but I cannot discern from the vague abstract how this is justified.
Additional key observations made by both Gilbert and Gatz are that among "several hundred" and "over a thousand" (respectively) spotted salamander egg masses observed in nature, each researcher recalled only a single instance of an egg mass lacking algae late in its development; the symbiosis appears to be nearly, but not completely, ubiquitous. Gilbert speculated that the egg mass lacking algae was located in an old stream bed, and so perhaps algae had been flushed from the system.
The failure of both Gilbert and Gatz to find algae within the reproductive tracts of female salamanders is in contrast to Kerney who supposedly found algae within adult salamander oviducts. This raises the possibility of vertical transmission of the symbiont, and that the salamanders themselves could be the vector bringing O. amblystomatis to novel habitats.
I wrote an email to Dr. Kerney last week to ask how he was dealing with the taxonomic impediments, and if he had any ecological insights regarding the colonization of O. ablystomatis in novel aquatic habitats such as the newly constructed pools at Heiberg. He replied that he has phylogenetic data that places "[their] local Oophila amblystomatis" in the Order Chlamydomonadales. Unfortunately, his research team lacks the resources to undertake more comprehensive phylogeographic analysis, but he speculated that a diversity of algal symbiont types could be associated with different salamanders. He added that it did not appear similar to any especially common northeastern species. In addition, Dr. Kerney confirmed that despite the strong evidence that O. amblystomatis is present in pond water and quickly colonizes newly deposited amphibian eggs, it has never been observed in a free-living state. He expressed a hunch that both vertical and horizontal algal acquisition might be at work, but resolving this experimentally has not been, nor will be, an easy task.
So, given some degree of cooperation by (or manipulation of!) reproductive spotted salamanders and wood frogs, we are poised to make some potentially interesting observations in our experimental system regarding the ecology of O. amblystomatis, with implications for the restoration of populations of amphibian species that enjoy the benefits of association with this ill-known alga(e?). James, Kim and I are in the initial phases of brainstorming experimental approaches to discerning vectors or reservoirs of O. amblystomatis. I wonder if any of the USC folks in the field have observed the tell-tale green egg masses in newly constructed pools down south, and within what kind of timeframes following construction?
This is to say nothing of the recently reported radical endosymbiosis, or what physiological titans spotted salamanders might become if they did not whisk themselves underground the first chance they get after metamorphosing....
Jim Arrigoni, SUNY-ESF
Monday, October 11, 2010
New paper on vernal pool amphibian and macroinvertebrate detection probabilities
Annie Curtis and Dr. Peter Paton at the University of Rhode Island have just published a paper titled "Assessing detection probabilities of larval amphibians and macroinvertebrates in isolated ponds" in the journal Wetlands. Although they describe the utility of their results within the framework of monitoring the ecological condition of isolated aquatic habitats such as vernal pools based on observations in 36 Rhode Island ponds, there are clear implications for my ambition to document community assembly in the Heiberg constructed pools. Curtis and Paton add a great deal of temporal resolution to the general phenological patterns described in the seminal paper by Wiggins et al. in 1980, "Evolutionary and ecological strategies of animals in annual temporary pools." The waxing and waning of detection probabilities for 8 amphibian species and 10 macroinvertebrate families between mid-May and the end of July are nicely portrayed in Figures 2 and 3. Also, the influence (or lack thereof) on detection probabilities of abiotic and habitat structure variables such as water temperature, pond depth, aquatic vegetation, and woody debris are instructive for designing a sampling protocol in the present and as habitat develops in the future.
-Jim Arrigoni, SUNY-ESF
-Jim Arrigoni, SUNY-ESF
Friday, September 24, 2010
Pitfall trapping underway
With the help of 16 SUNY-ESF undergraduate volunteers, 18 drift fence/pitfall trap arrays were installed at Heiberg over the Labor Day weekend. Each array consists of a 5-meter section of polyethylene tarp (the fence) and six 5-gallon buckets (the pitfalls) buried in the ground adjacent to the fence.
Half of the pitfall trap arrays are located in close proximity to the 39 pools that consititute the Hexagon Array, and half are distributed elsewhere throughout the forest, several hundred meters from recently constructed pools. The latter group will serve as controls with which to compare the amphibian population impacted by pool construction. Traps were opened on 9 September and undergraduate interns have been diligently checking them since, recording species ID and length of each animal. So far we have encountered robust numbers of seven species: American toads, green frogs, pickerel frogs, wood frogs, red-backed salamanders, red efts of eastern newts, and spotted salamanders.
We intend to repeat the effort next year and in 2012. Since the hexagon pools were constructed in early June, no wood frog or spotted salamander breeding occured in them. Green frogs have bred in approximately a quarter of these pools, but their tadpoles require a year to develop before metamorphosing, so we will not expect to see recruited froglets until next year. One single pool did have a late pair of American toads breed soon after it was created, and these have completed larval development. With the exception of this single clutch of toads, this year's trapping should represent Time Zero -- essentially a perspective of the landscape before being impacted by amphibian production associated with the pools. If the pools are functioning as breeding habitats for vernal pool-associated species, we expect to see a relative increase in metamorph wood frogs and spotted salamanders next autumn, and as we catch up with demographic lag times, increases in relative abundance of adults of these two species.
More images of the trap construction process can be viewed by clicking here.
-Jim Arrigoni, SUNY-ESF
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