[NatureNS] Frog Pond (Halifax) - Non-native Aquatic - Fanwort

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Date: Mon, 29 Dec 2014 12:04:19 -0400
From: Nicholas Hill <fernhillns@gmail.com>
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Something must be out of kilter in the Frog Pond; Invasive plants for
the most part, are indicators of a disrupted nutrient or disturbance
regime. The aquatic exotics do us a favour by pointing out lakes with
ecological health problems. The apparent outbreak of Cabomba
caroliniana at Frog Pond may be linked to a decline in that lake's
water quality.  Coliform warning was given in 2008 (HRM data) for
coliforms around 800 MPN/100mL ...in summer 2009 no exact figures were
available..in summer 2010, levels spiked to 3500 MPN/100mL  (the
highest in HRM?) and in 2011, levels were down to 600MPN range.

It should be reason for concern and an opportunity to track imbalances
in the signs of health in lakes and this plant should reasonably, also
be in Whimsical Lake if that lake has gone through the same water
quality disruptions. The plant is the warning of imbalance. Instead of
a purple bladderwort growth or the native floating heart, we get
Cabomba, doing the same as these other plants but doing it more
effectively when there is more nutrient in the water or at lower
oxygen levels in more stress. Recall the outbreak of the "invasive"
yellow floating heart. THis was not a biodiversity crisis but rather a
sign that something was out of kilter.

Nick

below attached from HRM 2008





Public Service Announcement

Frog Pond and Whimsical Lake Water Quality Advisory

Friday, September 5, 2008 - The public is advised that ecological
water quality samples taken August 25th at Whimsical Lake and the Frog
Pond has detected faecal coliform bacteria levels exceeding provincial
and federal recreational/swimming guidelines.

Whimsical Lake and the Frog Pond are not HRM supervised beaches.

These water test samples are taken as part of HRM's on-going
ecological water sampling program to help give long term data as to
the health of 62 sampled lakes and are not part of the weekly sampling
program undertaken at HRM's supervised beaches.

On Sun, Dec 28, 2014 at 4:20 PM, Dusan Soudek <soudekd@ns.sympatico.ca> wrote:
> This afternoon I had a chance to visit Frog Pond. The amount of floating
> Fanwort (Cabomba caroliniana ??) biomass there is quite impressive,
> particularly along the smallish coves of the northern basin. In places the
> Fanwort zone is several metres wide. Of course,  there is no quick way of
> telling how much of the pond's bottom is covered with this plant.
>
> The rhizomes were lush green, but I didn't observe any of the resident Black
> or Mallard ducks feeding on them. I briefly checked the nearby pond on the
> other (i.e., southern) side of Purcells Cove Road for Fanwort but didn't
> find any. It may be worthwhile to keep checking other nearby freshwater
> bodies (Whimsical Lake, Cunard Pond, Williams Lake) for spread of this
> invasive plant.
>
> Dusan Soudek
>
> -----Original Message----- From: Burkhard Plache
> Sent: Friday, December 26, 2014 6:35 PM
> To: naturens@chebucto.ns.ca
> Subject: Re: [NatureNS] Frog Pond (Halifax) - Non-native Aquatic
>
> Here is a link to a few photos of the specimens floating in clear water:
> https://www.dropbox.com/sh/5cqlzcbn93wayoh/AABLTH0_OET6amgcDO0bcvR8a?dl=0
>
> On Fri, Dec 26, 2014 at 11:04 AM, Nicholas Hill <fernhillns@gmail.com>
> wrote:
>>
>> Can you send an image of your aquatic?
>> No reports of Cabomba here that I can see. Have you considered the
>> bladderworts (e.g, purple bladderwort)?
>> Nick
>>
>> On Thu, Dec 25, 2014 at 1:27 PM, Burkhard Plache
>> <burkhardplache@gmail.com> wrote:
>>>
>>> For a number of weeks now, I had noticed a heavy accumulation
>>> of an aquatic herb at the shoreline of Frog Pond.
>>> Initially I assumed it might be Ceratophyllum (hornwort) or
>>> Myriophyllum (water milfoil), both reported from Nova Scotia.
>>>
>>> However, the plant has opposite leaves, which are fan-like,
>>> finely divided. I am now certain it is a species of Cabomba,
>>> most likely Cabomba caroliniana.
>>>
>>> The species is not native to NS, but used in aquariums.
>>> Maybe this introduction was the result of an aquarium dump.
>>> (Could have happened a few years back when a Gold Fish
>>> or a Koi was seen in the pond.)
>>>
>>> In other regions of the world Cabomba is a problematic
>>> invasive. Is it problematic here as well?
>>> Have people seen this in other parts of Nova Scotia?
>>>
>>>
>>> Wikipedia links to the species mentioned above:
>>> https://en.wikipedia.org/wiki/Ceratophyllum
>>> https://en.wikipedia.org/wiki/Myriophyllum
>>> https://en.wikipedia.org/wiki/Cabomba_caroliniana
>
>
>

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