Spatial Ecology of Fiddler Crabs, Uca pugnax, in Southern New England Salt Marsh Landscapes: Potential Habitat Expansion in Relation to Salt Marsh Change
Spatial Ecology of Fiddler Crabs, Uca pugnax, in Southern New England Salt Marsh Landscapes: Potential Habitat Expansion in Relation to Salt Marsh Change
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DOI：
10.1656/045.020.0213
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发表时间：
2013-06-01
影响因子：
0.4
通讯作者：
Zajac, Roman N.
中科院分区：
文献类型：
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作者：
Luk, Yi Chuan;Zajac, Roman N.
调查了沿着康涅狄格州中部长岛海峡海岸的招潮蟹Uca pugnax（大西洋沼泽招潮蟹）的空间分布与盐沼斑块结构的关系。盐沼景观结构的研究地点表现出的特点与其他系统的变化相一致，沿着美国大西洋沿岸在过去的几十年中，包括显着的向海侵蚀，低沼泽植物侵入高沼泽，改变组成的高沼泽植物斑块结构，沼泽枯死和溺水。我们的目标是确定是否U的空间格局。根据这些特征，居住在这些系统中的pugnax与以前报道的新英格兰南部不同。螃蟹洞穴的密度最高的低沼泽补丁互花米草（大西洋平滑灯心草）和无植被的泥沿着潮沟银行和蚊子沟。受海水侵蚀的低沼泽地区通常没有活螃蟹和洞穴。蟹洞密度变化复杂的补丁镶嵌在高沼泽地区。在广布的短S中，洞穴密度普遍较低。在几个地点，包括高沼泽地区的大部分互花米草斑块。然而，高洞穴密度，相当于低沼泽密度，被发现在某些高沼泽斑块类型和高地过渡区。这些包括米草（沼泽干草灯心草），Distichils Spicata（沙漠盐草），以及这些混合物的补丁，特别是在S。patens斑块全部或部分由裸露沉积物包围的植被丘组成。在几个网站，洞穴密度高，在高地过渡区补丁芦苇（普通芦苇）。因此，螃蟹洞穴分布是高度可变的，在当地的沼泽系统的空间尺度。Live U. pugnax在所有沼泽的所有斑块类型中都有规律的出现。我们的研究结果表明，更广泛的分布U。在整个南部新英格兰沼泽景观相对较高的密度比以前报道的pugnax。这一发现可能代表了一个案例的栖息地扩张，以应对盐沼的变化，可能是由于海平面上升和其他因素，创造高沼泽栖息地的各种补丁类型，可以支持居民人口的招潮蟹。这样一个占主导地位的盐沼物种，这可能会显着影响生态系统动态的扩张，可能会增加目前的盐沼变化模式和新英格兰南部海岸线沿着的动态的复杂性。
The spatial distribution of the fiddler crab Uca pugnax (Atlantic Marsh Fiddler Crab) in relation to salt marsh patch structure was investigated along the central Connecticut coast of Long Island Sound. Salt marsh landscape structure at the study sites exhibit characteristics consistent with changes noted in other systems along the US Atlantic coast over the last several decades, including significant seaward erosion, encroachment of low-marsh plants into high marsh, changing composition of high-marsh plant patch structure, and marsh dieback and drowning. Our objective was to determine whether the spatial patterns of U. pugnax inhabiting these systems differed from those previously reported for southern New England in light of these characteristics. Densities of crab burrows were highest in low-marsh patches of Spartina alterniflora (Atlantic Smooth Cordgrass) and unvegetated muds along tidal creek banks and mosquito ditches. Seaward-eroding low-marsh areas were generally devoid of live crabs and burrows. Crab-burrow densities varied across the complex patch mosaics in high-marsh areas. Burrow densities were generally low in the extensive short S. alterniflora patches that comprised much of the high-marsh area at several sites. However, high burrow densities, equivalent to low-marsh densities, were found in certain high-marsh patch types and upland transition zones. These included patches of Spartina patens (Marsh Hay Cordgrass), Distichils Spicata (Desert Salt Grass), and mixes of these, and particularly in S. patens patches wholly or partly comprised of hummocks of vegetation surrounded by bare sediment. At several sites, burrow densities were high in upland transition zone patches of Phragmites australis (Common Reed). As such, crab-burrow distributions were highly variable at local, within-marsh system spatial scales. Live U. pugnax were found regularly in all patch types on all marshes. Our results indicate a much broader distribution of U. pugnax at relatively high densities across southern New England marsh landscapes than previously reported. This finding may represent a case of habitat expansion in response to salt marsh change, likely due to sea-level rise and other factors, creating high-marsh habitats in a variety of patch types that can support resident populations of fiddler crabs. Such an expansion of a dominant salt marsh species, which can significantly affect ecosystem dynamics, may potentially increase the complexity of current salt marsh change patterns and dynamics along southern New England coastlines.