Sunday, November 21, 2010

Biodiversity - Rip Van Winkle and Climate Change.

Any subjective or objective analysis of recent extralimital bird occurrences in NJ reveals that several SE, US species are appearing more in NJ and in other NE, coastal states. Most of these species have static or declining US populations so the records are not a reflection of simple range expansions driven by healthy outbreeding.  
In recent years we have seen an increase in the NE of White-faced Ibis, White Ibis, Roseate Spoonbill, Anhinga, Magnificent Frigatebird, Black-bellied Whistling Duck, Sandwich Tern, Wilson's Plover, American Avocet, Ground Dove, White-winged Dove, Cave Swallows, Mississippi Kite, Swallow-tailed Kite and most recently (Nov 2010) the second NJ record for White-tailed Kite. Numerous breeding species are also expanding their ranges N but not S (see 4/07 issue Conservation Biology, http://news.mongabay.com/2008/0116-birds.html ). Additionally we are seeing reports of SE insects and fishes reaching further N than in past decades.

Are the higher taxa simply feeding on the lower taxa that are, for some reason, further N?  Indeed the kites feed on Odonates (dragonflies)some of which are migratory.  Many invertebrate, and vertebrate species including birds have a protracted fall migration tuned closely with temperatures which influences food availability. Perhaps dragonflies, other insects and fishes are lingering further N in summer and fall and this is attracting some of these S bird species N. Its seems that multiple species of animals are further N than they were just a few decades ago inferring a broad, large scale event is occurring. 
Lets imagine a scientifically trained Rip Van Winkle arrived on the modern scene. We will shield our guest from biased, special interest messages from both sides of the Climate Change issue (and J. Hartmann and L. O'Boyle, associates of mine).  We will give him NO temperature data or advise him that atmospheric CO2 levels have increased from 270 ppm to near 390 ppm in the geologic blink of 250 years. We will let him study only the zoogeographic distribution of animals over the millennium----compared to what we are witnessing recently. What will he report is causing these range expansions and records that are showing a rapid, northerly movement of animals in our area?

Wednesday, October 27, 2010

10/24/10 Observations on the lower Rahway River in Carteret and Linden, NJ.

Healthy populations of smaller invertebrates are needed to support larger animals and our native  biodiversity. When visiting the lower Rahway River one will observe many small creatures.  Lets look at some of the hundreds of thousands of invertebrates (e.g. clams, snails and crabs) that inhabit the longest unbridged river mouth ecosystem in N NJ.
 Along the inner bends of rivers there is increased sedimentation and food deposition which forms more extensive mud flats or beaches; these areas support important biological communities that are different than those found on the usually steeper banked, higher energy, outer bends of rivers.  On the major, inner turn of the lower Rahway is one of the widest tidal mud flats where several thousand eastern mudsnails forage.  Snails can be seen on this flat and throughout the lower river.

These eastern mudsnails, Ilyanassa obsoleta, tend to prefer areas of higher sedimentation as noted in this paper.

http://www.citeulike.org/user/sviscido/article/2911888sroughout


Another reference (title below) details food preferences of Diamondback Terrapins which includes various species of snails. The eastern mudsnails along with other invertebrates are important food resources for certain species of fish, birds and Diamondback Terrapins (Malaclemmys terrapin).  NBP and RRA are studying terrapins on the river.

Other species of invertebrates seen on the river include ribbed mussels (Geukensia demissa), the common marsh snail, or eastern melampus (Melampus bidentatus) and at least two species of fiddler crabs (Uca pugnax and Uca minax).  All these animals are eaten by terrapins.   The common marsh snail feeds on Smooth Cordgrass (Spartina alterniflora) so its indirectly  important for terrapins to control the growth of the invasive phragmites reed.

Varied and specific sections of rivers, such as inner bends and marsh free of phragmites, that support high densities of invertebrates are important to the ecology and biodiversity of an area.



Observations 10/24 1600 to 1815

Eastern Mudsnail  (tens of thousands)

Atlantic Marsh Fiddler Crab (hundreds) Uca pugnax

Brackish Water Fiddler Crab (10) Uca minax

Black-Crowned Night-Heron

Great Blue Heron 2

Black Duck 15

Wood Duck 5

Gadwall 4

Mallard 7

Canada Goose 40 residents, 5 migrating

Killdeer 2

Greater Yellowlegs 8

Northern Harrier (female and imm.)

Merlin

American Kestrel 2

Hermit Thrush 5

Ruby-crowned Kinglet 3

Golden-crowned Kinglet 5

Pine Warbler

Palm Warbler 3

Yellow-rumped Warbler 30+

White-crowned Sparrow 5 (imm.)

Field Sparrow 2

Savannah Sparrow 6

Swamp Sparrow 20+

White-throated Sparrow 20+

Song Sparrow 25+

House Finch 7

American Goldfinch 6

Opossum

White-tailed Deer 8


Title mentioned above: ASSESSMENT OF PREY AVAILABILITY FOR DIAMONDBACK TERRAPINS IN A CONNECTICUT SALT MARSH
Thanks Fred Virrazzi

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Sunday, October 17, 2010

Rahway River History Walk 10-16-10 Cranford NJ

The Rahway River Association (RRA) led a history walk along the Rahway River in Cranford, NJ.  This stretch was once called the Venice of NJ; it was a center for recreation, family activities and transportation. The walk started at Hanson Park and snaked one mile south by historic buildings, grain and lumber mills and dams.  Thanks to all the attendees and Steve Jandoli and Lynda Feder for interpreting the sites.



The Rahway River Association (RRA) led a history walk along the Rahway River in Cranford, NJ. This stretch was once called the Venice of NJ; it was a center for recreation, family activities and transportation. The walk started at Hanson Park and snaked one mile south by historic buildings, grain and lumber mills and dams. Thanks to all the attendees and Steve Jandoli and Lynda Feder for interpreting the sites.

omments are numbered and briefly described here:      
   1. you had sighting
   2. general, wariness, sightings
taxpayer, Kulivan sighting of pair, sightings
someone you know had sighting , sightings, video