2 15 Abstract 16 Mangrove expansion monopolizes estuarine landscapes by diminishing habitat diversity and 17 hence biodiversity. Physical landcover types, including mangrove vegetation, influence polychaete 18 and avifauna habitat uses. The connections between the physical to biota-associated landscapes 19 warrant investigation. We determine how to best describe the landscape in a mangrove-vegetated 20 wetland according to the physical, polychaete and bird domains and identify what physical 21 attributes would affect the biota-associated landscapes. Differences among the physical and biota-22 associated landscapes were evaluated using multivariate ordination analyses. Six physical 23 landcover types were aligned along elevation, inundation and sedimentary gradients. The 24 polychaete-associated landscape was structured by three landcover types, mainly mangroves and 25 tidal flats with intermediate and high inundation. Deposit-feeding spionid and nereid, carnivorous 26 goniadid and suspension-feeding sabellid polychaetes depended on the different landcover types. 27 Shorebirds occurred distinctively in tidal flats with large, open surface areas. Egrets characterized 28 tidal flats and mangroves, and foliage and ground gleaners characterized mangroves. Open tidal 29 flats are crucial to polychaetes, which are the main prey of shorebirds and are also important to 30 egret foraging. Our results suggest that effective management strategies for conserving these 31 migratory birds require the maintenance of open tidal flats in the landscape. 32 33 Keywords: Landcover types; Physical setting; Biota-coupled landscape; Polychaete assemblage; 34 Bird assemblage 3 35 Introduction 36 Essential components of a healthy mangrove ecosystem include mud and sand flats, tidal 37 waterways, shallow water areas and circulating waters in addition to mangrove stands [1, 2]. These 38 mosaic and interconnected landcover types make mangrove ecosystems varied in terms of 39 landscape function and the production of both terrestrial and aquatic organisms [3-5]. Furthermore, 40 mangrove ecosystems are also among the most threatened ecosystems on Earth due primarily to 41 the devastating effects of anthropogenic activities [6, 7] and natural disturbance [8]. Assessments 42 of the relationships between the supplies provided by mangroves and demand from human society 43 have demonstrated intimate bottom-up and top-down connections between the functions of 44 mangrove ecosystems and the services they offer to human wellbeing [9]. When considering 45 mangrove trees alone, they compose a simple ecosystem with limited vegetation niches and low 46 bird species richness [10, 11]. At the landscape level, however, landscape heterogeneity within 47 both mangrove ecosystems and their surroundings is crucial in characterizing mangrove-dependent 48 bird assemblages [11-13]. Mangroves have been found to have both positive and negative roles in 49 ecosystems. For example, as they act as both foundation species and ecosystem engineering 50 species, mangroves ca...