Re: [vernalpool] Re: decontamination protocols

>
> Hi Stephen
>
> Thanks for your reply and sorry to be slow geting back to you. You raise
> some interesting issues to consider. It is important to note that, in my
> experience, pretty few people in Mass. or New England will chemically
> decontaminate their gear when going between nearby vernal pools. Having
> worked on chytridiomycosis research and been interested in amphibian disease
> ecology, I was an early adopter of decon protocols for field gear, carrying
> spray bottles of bleach around with me.
>
> However, I have also witnessed the, in my opinion, wasteful and ineffective
> decontamination policies at some locations, instituted with the express
> purpose of limiting the spread of amphibian disease. As I've already argued,
> there is little logic in taking such measures to disinfect field gear *against
> amphibian pathogens* between visits to adjacent pools in the same local
> watersheds when amphibians and other wildlife move so readily between them.
> (having studied amphib migration patterns, I have directly observed such
> movement on many occasions). Moreover, much of the field decontamination
> procedures, such as ones that I've complied with when working at National
> Parks, are probably pretty ineffective - just spraying some bleach solution
> on waders that are coated with pond gunk is unlikely to sterilize them.
>
> Likewise, concerns about accidentally moving the other subjects of my own
> vernal pool interest, *aquatic insects*, between nearby pools on field
> gear likewise seem misplaced as the insects are such effective dispersers as
> adults. You mentioned that *algae* are effectively moved between nearby
> wetlands, the same is also undoubtedly true of the movement of *duckweed
> and plant propagules* by wildlife vectors. Some crustaceans are also
> likely good at dispersing themselves, *crayfish *by walking and *many
> amphipods and isopods* may be able to disperse between wetlands in our
> rather wet corner of the world via groundwater.
>
> So, I have grown skeptical about the merits of disinfecting field gear when
> moving between nearby wetlands. Your concern about avoiding the
> homogenization of small wetlands is a very valid one. I still wonder why
> boots and reasonably rinsed nets are likely to homogenize the biota when the
> large volume of mammal, bird, insect, amphibian, and reptile traffic that
> typically link nearby wetlands in New England does not already do the
> homogenizing? (Clearly it's irresponsible to carry glops of pond muck
> between wetlands in your dip net, I definitely believe in and practice
> rinsing nets of muck in the place you've been collecting.)
>
> The studies that you cite sound compelling and if nearby populations of *cladocerans
> *(like *Daphnia*)*,* for example, tend to be genetically isolated from one
> another, this may be a good argument for bleaching between all wetlands that
> are not already interconnected by surface water. But im not quite ready to
> buy into that yet.

> What I wonder is this:

1) are the studies that you cited from New England or inland freshwater
areas of the eastern US? I can imagine reasons why, for example, cladoceran
populations in nearby pools would be much more distinct from one another in
say desert rock pools or in tiny rain pools on rocky shores than they are in
New England. In arid areas and seashores with tiny pools there would be
relatively little wildlife traffic between nearby pools (both the
terrestrial matrix would be less hospitable to wildlife vectors and to
aquatic organisms stranded in between pools and there would be less food on
offer to potential vertebrate or invertebrate vectors). Note that the
certifiable "vernal pools" in our area that members of this forum typically
speak of tend to be a part of the broad spectrum among wetland types of
various hydrological regimes in our rather wet part of the world and that
they have very few really distinct floral or faunal elements (in this they
are unlike California vernal pools).

2) and again... Since high volumes of vertebrate and invertebrate traffic
between nearby vernal pools is the rule in most areas of New England, why
are these vectors NOT dispersing tiny crustaceans if dip nets and waders are
likely to be effective dispersers of the same species? Note, of course,
that merely finding differences in aquatic crustacean species composition
between adjacent vernal pools does not mean that there is no dispersal of
those species between the pools - it may simply be that either habitat
differences or priority effects have kept some of the species from being
established in some of the pools. (i.e it is easy to find pools that are
vey close to each other and yet differ in breeding amphibian species
composition even though those amphibians have no problem whatsoever moving
between the pools.)

Sorry to be so long-winded, this is an important issue and I don't pretend
that I have "the right" answer. I am interested in learning more.

>
> Best Wishes
> Bryan

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