SAND DUNE REGION OF SAGINAW BAY. 21 



The habitat distril^utioii of the flora and fauna has been considered 

 more or less completely by the \mters on the different groups, so that 

 all that will be attempted here is a brief outUne of the general con- 

 ditions. 



Sayid Ridges: This habitat comprises the dry sand ridges and grades 

 down into the swani])s and to the shore of Saginaw Bay. Most of the 

 ridges are clothed with an open growth of oaks, jack pine, large- 

 toothed aspen, sand cherry, choke cherry and wild red cherry, with 

 scattering white and Norway pines and a ground cover of such forms 

 as black huckleberry, bearberry, New Jersey tea, hairy puccoon, winter- 

 green, golden-rod, etc. In other words the society is xerophytic. 

 (Plate IV b) 



The fauna of the sand ridges is less characteristic because as a rule 

 less closely associated ^^dth the soil. However, certain relations are 

 evident.- The numerous forms, such as myriapods, snails, l^eetle larvae, 

 earthworms and salamanders, usually found in the humus and decaying 

 logs in mesophytic woods are nearly entirely absent from the ridges 

 but are better represented on the borders of the swamps, where some 

 humus has formed under the deciduous shrubs and trees. The absence 

 of these forms from the ridges is due to the lack of humus and the 

 fact that the decaying logs are usually too dry. The few found on the 

 ridges were nearly always in or under the logs. On the other hand, 

 we found on the ridges an abundance of forms not usually found in num- 

 l)ers in mesophytic woods. Among these are to be mentioned the 

 hog-nosed snake, grasshoppers, ant-Hons, cicadas, the mollusk, Polygyra 

 albolabris maritima, and the field sparrow. 



Beach of Saginaw Bay: From the end of Sand Point eastward the 

 Ij.each of Saginaw Bay is practically pure sand. It may be di^'ided 

 into two parts — a lower washed by the summer waves and devoid 

 of vegetation, and an upper part that is washed by the winter waves, 

 strewn with logs and supporting a few annual plants such as Cakile 

 edulenta, Arabis lyrata, and Triglochin palustris. The outer dune 

 arises directly from the beach proper. The outer face of this dune 

 is covered by a sparse gro^^i:h of xeroph}i;ic grasses and herbs such as 

 Artemisia caudata, beach pea, Cirsium pitcheri, two prominent xero- 

 phytic grasses, Ammophila arenaria and Calamovilfa longifolia. etc., 

 and the top by the vegetation of the older dunes with a greater pro- 

 portion of juneberry. choke cherr}', Cornus baileyi, and sand cherry. 

 The trees that occur l)oth here and on the older ridges are generally 

 more scrubby in this habitat. (Plates I, III b.) 



The fauna of this group of habitats is ver\' meager, the resident 

 spotted sandpiper and the numerous migrant sandpipers and plovers 

 are characteristic of the beach proper, and also generally to be found 



