muzled 140 Posted June 13, 2018 Share Posted June 13, 2018 This is quite interesting, I've always thought they were bloody invasive 'pests', and according to this guy that would be correct. https://www.nzgeo.com/stories/mangroves-allies-or-invaders/ New Zealand is the only country in the world where the mangrove is expanding its area of occupation. Is this expansion good for New Zealand’s marine environment? We don’t believe it is, because it appears to be occurring at the expense of other habitats, such as shellfish beds, sea-grass beds, flounder habitat and wading-bird habitat, as well as recreational areas such as sandy beaches and stretches of open water Quote Link to post Share on other sites
El Toro 97 Posted June 13, 2018 Share Posted June 13, 2018 All mangroves must die Quote Link to post Share on other sites
John B 106 Posted June 13, 2018 Share Posted June 13, 2018 The hint of someone removing a mangrove a few years ago was enough to get a body charged and fined. Friends of mine with coastal property were warned and very wary. Now you see local gummint or who? steam cleaning/killing the seedlings off mud flats. As seen at mahunga drive around the pylons in the upper manukau harbour Quote Link to post Share on other sites
wheels 543 Posted June 14, 2018 Share Posted June 14, 2018 Have a read up re mangroves. There is a NZ native species that have been here for thousands of years. They offer a habitat to breading fish, where the eggs are laid and then the little fellows live in relative safety till they are big enough to roam out into deeper less protected waters. They also stabilize the silt within esturies to stop it being washed away.The fact that they are spreading may well be due to other factors perhaps. Like something else has been removed from the waterway to allow the space for them to spread. I don't know, just a thought. Quote Link to post Share on other sites
Black Panther 1,591 Posted June 14, 2018 Share Posted June 14, 2018 Silt build up from clearing land upstream. The sand becomes mud then they take over. Easy to see where I live. Quote Link to post Share on other sites
Sudden5869 17 Posted June 14, 2018 Share Posted June 14, 2018 I was under the impression Mangroves flourished when silt runs into the estuary and harbour. The additional silt makes it easier for the Mangroves to take hold. Whangamata Harbour is an example of this with the forestry surrounding it. We an encouraging Mangroves with our use (misuse) of land. Quote Link to post Share on other sites
Black Panther 1,591 Posted June 14, 2018 Share Posted June 14, 2018 I was under the impression Mangroves flourished when silt runs into the estuary and harbour. The additional silt makes it easier for the Mangroves to take hold. Whangamata Harbour is an example of this with the forestry surrounding it. We an encouraging Mangroves with our use (misuse) of land. Agreed. Mangroves are a symptom , not the cause. Quote Link to post Share on other sites
erice 732 Posted June 14, 2018 Share Posted June 14, 2018 at little shoal bay they seem to have come up with a reasonable solution ie not all or nothing the locals have been allowed to carve out mangroves from a nicely slopped sandy bit to make a beach for the kids to play in but leaving the other 90%? on the mud for small fish to hide behind, oxygenate the water? and consume? some of the nitrate run-off Quote Link to post Share on other sites
The big T 41 Posted June 14, 2018 Share Posted June 14, 2018 Mangroves can be frost tender - Roundup I think gives the same gradual die back. Just saying. Quote Link to post Share on other sites
Vorpal Blade 89 Posted June 14, 2018 Share Posted June 14, 2018 The results of that effort really needs a photo but I reckon it was a complete waste of time . I'll get a pic when Im there over the weekend. It has left the "beach" as unusable as it ever was and a bald patch of mud with the vertical root-sprouts bits still poking out of the mud and hardly appealing. Quote Link to post Share on other sites
harrytom 648 Posted June 14, 2018 Share Posted June 14, 2018 Yes there is a species of mangrove exclusive to NZ,mangroves grow north of Tauranga from memory.They provide a habitat for fish to hide,unlike the tropics etc where fish actually come in to the shallows to breed,They do not do this in NZ. The thought was fresh water killed them when cut and rots the roots but how do explain the ones growing by the old Kopu bridge in Thames in a paddock??they have clear most from Pahurehure lagoon but some greenie claims to of found a foot print in the mud from an endangered bird, Most of the mangroves have gone and the silicone sand beach is returning.But the mud needs to sucked up and removed,someone in council said remove the mangroves and the tide will flush out the silt.Hmm yes that will work on the out going tide and when tide changes will come back in I would of thought. Bayswater marina was suppose to of gone ahead mid 70s but didnt due to greenies saying it will effect the ecology,whats the results of the ecology now the marina in in??bet the crabs still in ngataranga bay along with flounder,bet the old devonport tip is still leaching out toxins. Quote Link to post Share on other sites
DrWatson 378 Posted June 14, 2018 Share Posted June 14, 2018 Have a read up re mangroves. There is a NZ native species that have been here for thousands of years. They offer a habitat to breading fish, where the eggs are laid and then the little fellows live in relative safety till they are big enough to roam out into deeper less protected waters. They also stabilize the silt within esturies to stop it being washed away. The fact that they are spreading may well be due to other factors perhaps. This is correct. I think there may even be two species if my memory serves me correctly. Mangroves also hep prevent against storm surges, and a number of other important things. Shallow harbours without mangrove buffers suffer higher levels of algal bloom. I.e. sea lettuce Quote Link to post Share on other sites
Steve Pope 243 Posted June 14, 2018 Share Posted June 14, 2018 Mangroves are natures reclamation machine. Quote Link to post Share on other sites
Kevin McCready 83 Posted June 15, 2018 Share Posted June 15, 2018 LOL. An old article from 2004 by a coastal engineer with a vested interest in mangrove removal. Quote Link to post Share on other sites
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.