24 de setembro de 2019

Indigenous biodiversity

I have 1,612 verified observations on iNaturalist between Auckland and Whangarei documenting 552 species (mostly invertebrates) covering forest, freshwater, intertidal and marine habitats. I don't take many photographs of plants. Of these observation 96 or 17% of species were introduced. Here is a break down showing areas where I have found more or less introduced species:

Hauturu Aotea Tawharanui East Auckland Waitakeres Hunua Ranges Rangitoto / Motutapu / Motuihe Motukorea Mungatapere
Observations 206 149 141 197 77 94 71 33 159
Species 86 84 86 120 57 64 52 25 83
Introduced 6 12 8 35 1 4 11 4 9
Percent introduced 7 14 9 29 2 6 21 16 11

I expected the restored and protected islands in the Hauraki Gulf to have a smaller percent of introduced species. I think the high number of introduced species (compared to the Waitakeres and the Hanua Ranges) reflects the islands farmed history with islands like Motukorea and Motutapu still dominated by kikuyu. The larger and older the forest the more indigenous biodiversity.

Publicado em 24 de setembro de 2019, 09:02 PM por shaun-lee shaun-lee | 3 comentários | Deixar um comentário

02 de fevereiro de 2019

Thermal imaging at Tāwharanui

I do a lot of invertebrate photography at Tāwharanui Regional Park, I know there are lots of mice there but I have only ever seen one. On the first of February 2019 I took my friend Pieter (who has a fantastic thermal imaging camera) up to see if we could see them and anything else.

We saw mice straight away and counted nine from the start of the Ecology Bush Track (at Anchor Bay) to the boot cleaning station. Over the same distance we only saw three birds. Of the nine I think only two were more than 20cm off the ground with the highest one on a tree fern at chest height. The mice did not move much when we approached but stayed still. When we turned our torches on to see them directly with our eyes they were invisible, hidden behind a leaf or small piece of scrub.

The most interesting thing happened when I spotted a Puriri Moth crashing around to the side of the track, Pieter told me it would emit a heat signature and turn up on the camera, we tried it and it was clearly visible! Not as hot as a mouse but still visible. It would have been interesting to see if it was still visible after being still for 20mins or so.

Publicado em 02 de fevereiro de 2019, 02:24 AM por shaun-lee shaun-lee | 2 observações | 1 comentário | Deixar um comentário

29 de janeiro de 2018

Pataua mussel bed

I went for a snorkel in the Pataua Estuary (North East of Whangarei) to look for a soft sediment intertidal mussel bed seen in 2016. Soft sediment mussel beds are quite interesting as they were a dominant habitat in the Hauraki Gulf but were over fished and are now functionally extinct.

First we asked a local about the mussels. She said they were gone now (cleaned out by school camps who took them when they were quite small) but that we might find some in the channel. We spent hours in the water, mostly because it was so clear (no mud, just sand shell and rock substrate). We investigated the channel from the bridge to the mouth of the estuary. This covered the area they were reported in 2016 which I think is visible in Google Earth (view historical imagery). We just found dead mussel shell but there were a few juveniles growing in coralline (which is interesting) and attached to pebbles.

The estuary is awesome, we saw so much cool stuff (below). We only saw one blue mussel and a few horse mussels. I hope they get the green-lipped mussel bed back, in the meantime the octopus will have to do with pipi.

Publicado em 29 de janeiro de 2018, 03:59 AM por shaun-lee shaun-lee | 13 observações | 0 comentários | Deixar um comentário

01 de janeiro de 2018

Swimming with sharks

I went for my first swim with my son at Goseberry Flat, Great Barrier Island on the 31st of Dec 2017. We immediately noticed a lot of eagle rays, at most we might see one eagle ray every 50 meters (at other beaches) but we were seeing at least one every 10 meters here. The rays were also harder to photograph than usual (moving away from us). After a small school of silver trevally joined us we were quite impressed with the sea life at this beach!

We finished our swim and were told by a drone operator on the beach that there was a school of 20 or so hammerhead sharks swimming only meters from us. I went straight back out to look for tham but they had moved on. Here is the drone footage on Facebook https://www.facebook.com/sarah.judkins.12/videos/10156927768523056/

Publicado em 01 de janeiro de 2018, 11:44 PM por shaun-lee shaun-lee | 4 observações | 0 comentários | Deixar um comentário