scholarly journals Conservation Across Aquatic-Terrestrial Boundaries: Linking Continental-Scale Water Quality to Emergent Aquatic Insects and Declining Aerial Insectivorous Birds

2021 ◽  
Vol 9 ◽  
Author(s):  
David W. P. Manning ◽  
S. Mažeika P. Sullivan

Larval aquatic insects are used to assess water quality, but less attention is paid to their adult, terrestrial life stage, which is an important food resource for declining aerial insectivorous birds. We used open-access water-quality, aquatic-invertebrate, and bird-survey data to study how impaired water quality can emanate from streams and lakes through changes in aquatic insect communities across the contiguous United States. Emergent insect relative abundance was highest across the West, in northern New England, and the Carolinas in streams, and highest near the Great Lakes, parts of the Southwest, and northern New England for lakes. Emergent insects declined with sedimentation, roads, and elevated ammonium concentrations in streams, but not lakes. The odds that a given taxon would be non-emergent increased by up to 2.0× as a function of pollution tolerance, underscoring the sensitivity of emergent aquatic insects to water-quality impairment. However, relationships between bird populations and emergent insects were generally weak for both streams and lakes. For streams, we observed the strongest positive relationships for a mixture of upland and riparian aerial insectivorous birds such as Western Wood-Pewee, Olive-sided Flycatcher, and Acadian Flycatcher and the strongest negative association for Purple Martin. Different avian insectivores responded to emergent insect abundances in lakes (e.g., Barn Swallow, Chimney Swift, Eastern Wood-Pewee, Common Nighthawk). In both streams and lakes, we observed stronger, but opposing, relationships between several aerial insectivores and the relative abundance of sensitive insect orders (E)phemeroptera, (P)lecoptera, and (T)richoptera (positive), and pollution tolerant individuals (negative). Overall, our findings indicate that emergent insects are negatively correlated with pollution tolerance, suggesting a large-scale loss of this nutritional subsidy to terrestrial environments from impaired aquatic ecosystems. While some bird populations tracked scarcities of emergent aquatic insects, especially EPT taxa, responses varied among species, suggesting that unique habitat and foraging behaviors likely complicated these relationships. Strengthening spatial and temporal concordance between emergent-insect and bird-survey data will improve our ability to interpret species-level responses over time. Thus, our analysis highlights the need for developing conservation and biomonitoring strategies that consider the cross-ecosystem effects of water quality declines for threatened insectivorous avifauna and other terrestrial wildlife.

Genes ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 40
Author(s):  
Liang Cui ◽  
Bitong Zhu ◽  
Xiaobo Zhang ◽  
Zhuhua Chan ◽  
Chungui Zhao ◽  
...  

The elevated NH3-N and NO2-N pollution problems in mariculture have raised concerns because they pose threats to animal health and coastal and offshore environments. Supplement of Marichromatium gracile YL28 (YL28) into polluted shrimp rearing water and sediment significantly decreased ammonia and nitrite concentrations, showing that YL28 functioned as a novel safe marine probiotic in the shrimp culture industry. The diversity of aquatic bacteria in the shrimp mariculture ecosystems was studied by sequencing the V4 region of 16S rRNA genes, with respect to additions of YL28 at the low and high concentrations. It was revealed by 16S rRNA sequencing analysis that Proteobacteria, Planctomycete and Bacteroidetes dominated the community (>80% of operational taxonomic units (OTUs)). Up to 41.6% of the predominant bacterial members were placed in the classes Gammaproteobacteria (14%), Deltaproteobacteria (14%), Planctomycetacia (8%) and Alphaproteobacteria (5.6%) while 40% of OTUs belonged to unclassified ones or others, indicating that the considerable bacterial populations were novel in our shrimp mariculture. Bacterial communities were similar between YL28 supplements and control groups (without addition of YL28) revealed by the β-diversity using PCoA, demonstrating that the additions of YL28 did not disturb the microbiota in shrimp mariculture ecosystems. Instead, the addition of YL28 increased the relative abundance of ammonia-oxidizing and denitrifying bacteria. The quantitative PCR analysis further showed that key genes including nifH and amoA involved in nitrification and nitrate or nitrite reduction significantly increased with YL28 supplementation (p < 0.05). The supplement of YL28 decreased the relative abundance of potential pathogen Vibrio. Together, our studies showed that supplement of YL28 improved the water quality by increasing the relative abundance of ammonia-oxidizing and denitrifying bacteria while the microbial community structure persisted in shrimp mariculture ecosystems.


1997 ◽  
Vol 54 (7) ◽  
pp. 1593-1607 ◽  
Author(s):  
T R Whittier ◽  
D B Halliwell ◽  
S G Paulsen

Fish assemblages were sampled in 195 randomly selected lakes in the northeastern United States during the summers of 1991-1994. Most lakes in northern Maine had three to seven minnow species, constituting 40-80% of species in each lake. Lakes in New Jersey, southern New York, and southern New England rarely had minnows, other than golden shiner (Notemigonus crysoleucas). Lakes in the Adirondacks and the remainder of northern New England had intermediate numbers. We examined minnow native ranges and autecology and evaluated species richness related to littoral predators and human disturbance. Sample data suggested alteration in the minnow assemblages over much of the region. The most consistent factor related to minnow species richness was the presence of littoral predators. Median number of minnow species was two in lakes lacking predators and zero in lakes with predators. Non-native predators, especially Micropterus spp., have been introduced throughout the Northeast; 69% of the sampled lakes had non-native predators. In the absence of predators, minnow species declined with increased human activity in the watershed and along lake shorelines. Only in northern Maine did lake minnow assemblages seem relatively intact.


2003 ◽  
Vol 79 (5) ◽  
pp. 936-947
Author(s):  
Debra Straussfogel ◽  
Theodore Howard ◽  
Sylvain Masse ◽  
Difei Zhang

The objectives of this mail survey of sawmills in the Chaudière-Appalaches region of southern Québec were (1) to establish the level of transborder interaction of these sawmills, with regard to wood sources and final markets; (2) to discover their perceptions of local versus international economic and business factors with regard to their business success; and (3) to examine the role and importance of the size of the sawmills in Chaudière-Appalaches relative to the nature of their engagement in either raw material import from or finished product export to the US. Our results demonstrate that a transborder forest economy exists and that the conception of "local" in transboundary regions must be flexible enough to permit resource management strategies, that, to some extent, ignore national boundaries. Key words: sawmill industry, transborder interaction, Chaudière-Appalaches, Québec, Northern New England


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