Biodiversity and rarity distributions of native freshwater fish in an agricultural landscape: the importance of β diversity between and within water‐body types

Abstract

Farmland expansion is a growing threat to aquatic biodiversity. Identifying conservation priority areas in agricultural landscapes is a key issue in freshwater ecology and information on the spatial variability of aquatic biodiversity is vital for prioritization. This study examined patterns of farmland fish assemblages across various water‐body types in northern Japan to develop an effective management plan for freshwater fishes. Water bodies were classified into five types: small lowland streams, small upland streams, large rivers, man‐made ditches, and wetland ponds, and native fishes were collected from each type. The contribution of fish diversity between water‐body types (β2) to the regional fish diversity (γ) was investigated through additive diversity partitioning. Within each water‐body type, the contributions of between‐site diversity (β1) and within‐site diversity (α1) were also examined. The assemblage composition, species richness, and rarity were compared among the water‐body types. The assemblage composition differed significantly among most of the water‐body types, which indicated that the landscape classification was appropriate for representing spatial variations in fish diversity. Additive diversity partitioning revealed that the contributions of β1 and β2 to γ fish diversity were relatively high at 38.2% and 37.3%, respectively, followed by a 24.5% contribution of α1 diversity. This finding demonstrates that the best strategy for conserving regional farmland fish diversity is to preferentially select areas containing various water‐body types as a conservation unit. Among the water‐body types, ditches and streams exhibited the higher contribution ratio for β1 diversity, whereas the contribution of β1 diversity was lower in wetland ponds. The differences in the contribution of β1 diversity might be attributed to human‐induced factors, such as habitat fragmentation or shrinking. These results emphasize that further studies are needed to clarify the factors influencing the β1 diversity of farmland fish to develop better management strategies for each water‐body type. Copyright © 2015 John Wiley & Sons, Ltd.

Fish community response to environmental variations in an impacted Neotropical basin

“…Upstream the site 3, there are agricultural areas close to the river and extensive sloping areas occupied by urban zoning, in which the original riparian vegetation was suppressed and replaced by grass. (Ishiyama, Sueyoshi, Watanabe, & Nakamura, 2016;Portt, Coker, Ming, & Randall, 2006). Between the sites 3 and 4, the VRB receives inputs from the Pilão de Pedra and Lajeado Grande streams, which load urban sewage and garbage from extensive residential areas (Sequinel et al, 2011), added to the effluents from a sewage treatment system (Sanitation Company of Paraná -SANEPAR).…”

“…Although complex, the current findings are supported by an appropriate sampling effort of the communities. The results of the rarefaction curves and the absence of significance among the abundances and variances of each fishing gear allowed the combined use of data (Fauconnet et al, 2015;Ishiyama et al, 2016). The results of the rarefaction curves and the absence of significance among the abundances and variances of each fishing gear allowed the combined use of data (Fauconnet et al, 2015;Ishiyama et al, 2016).…”

“…(Supporting Information SM1 contains images of each sampling area). (Ishiyama, Sueyoshi, Watanabe, & Nakamura, 2016;Portt, Coker, Ming, & Randall, 2006). The samplings were synoptic at the four sites, between Saturday 5 p.m. to Sunday 5 p.m.…”

Contribution of small isolated habitats in creating refuges from biological invasions along a geomorphological gradient of floodplain waterbodies

“…Swamp minnow is listed as an endangered species (near threatened) by the Ministry of the Environment of Japan, and the need for the conservation of this species has increased. Among waterbodies, floodplain ponds are a major remnant habitat for swamp minnow in human‐altered landscapes (Ishiyama, Sueyoshi, Watanabe, & Nakamura, ). The two invasive minnows are major invaders in floodplain ponds of northern Japan (Figure ), and as omnivores, they are potential resource competitors (Kawanabe & Mizuno, ).…”

“…Swamp minnow is listed as an endangered species (near threatened) by the Ministry of the Environment of Japan, and the need for the conservation of this species has increased. Among waterbodies, floodplain ponds are a major remnant habitat for swamp minnow in human-altered landscapes (Ishiyama, Sueyoshi, Watanabe, & Nakamura, 2016).…”