Effects of intensive agriculture and hydrological changes on macrophyte and macroinvertebrate assemblages in lowland riverine wetlands

The aim of this study was to investigate the effects of agricultural land use and periods of hydrological variability on the environmental variables, as well as macrophyte and macroinvertebrate assemblages in lowland riverine wetlands. We compared two wetlands with intensive agricultural land use against two others with extensive livestock considered references for the region during a normal and a dry flow period. Nutrient concentrations were significantly higher in agricultural riverine wetlands. These wetlands exhibited higher relative coverage of floating anchored macrophytes and the absence of submerged vegetation. They showed significantly lower taxonomic richness and density of macroinvertebrates and a higher relative abundance of scrapers and predators. Wetlands of both land uses had a lower total density of macroinvertebrates and a higher proportion of tolerant desiccation taxa in the dry period. Particular differences between land uses, such as lower dissolved oxygen concentrations and lower macroinvertebrate diversity in agricultural wetlands, were found during the dry period. These findings indicate that the differences between land uses increased during the aforementioned period. This study provides evidence of the effects of the surrounding landscape and hydrologic periods in the environmental characteristics as well as the macrophyte and macroinvertebrate assemblages of the riverine wetlands studied.

MACROPHYTIC DIVERSITY OF SOME WETLANDS OF JAMMU REGION, J&K, INDIA

The present ecological investigation communicates the macrophytic diversity of six wetlands of Jammu region comprising of three lacustrine wetlands viz. Surinsar, Mansar and Sanasar and three riverine wetlands i.e., Gharana, Kukarian and Pargwal. A total of 43 macrophytic species belonging to 34 genera and 24 families with 30 monocot species and 13 dicots were recorded, thereby showing the dominance of monocot flora. Among various ecological groups, emergent with 22 species showed qualitative dominance over submersed (13 species) and rooted floatingleaved types=free-floating types (4 species each). The present study revealed that there is no well-marked variation in the macrophytic groups among the studied wetlands and mostly mixed distribution was observed. Maximum macrophytic diversity was recorded in Mansar wetland (26) followed by Pargwal (22), Surinsar (16), Gharana (14), Kukarian (14) and Sanasar (11). The present study provides a baseline information on the macropytes of wetlands for subsequent research on the vital aspects of these aquatic ecosystems and would be helpful in planning management strategies.

Will fencing floodplain and riverine wetlands from feral pig damage conserve fish community values?

Installation of feral pig (Sus scrofa) exclusion fences to conserve and rehabilitate coastal floodplain habitat for fish production and water quality services remains untested. Twenty-one floodplain and riverine wetlands in the Archer River catchment (north Queensland) were surveyed during post-wet (June-August) and late-dry season (November-December) in 2016, 2017 and 2018, using a fyke net soaked overnight (~14-15hrs) to test: 1) whether the fish assemblage are similar in wetlands with and without fences; and 2) whether specific environmental conditions influence fish composition between fenced and unfenced wetlands. A total of 6,353 fish representing twenty-six species from 15 families were captured. There were no wetland differences in fish assemblages across seasons, years and for fenced and unfenced (PERMANOVA, Pseudo-F <0.589, P<0.84). Interestingly the late-dry season fish were far smaller compared to post-wet season fish: a strategy presumably in place to maximise rapid disposal following rain and floodplain connectivity. In each wetland a calibrated Hydrolab was deployed (between 2-4 days, with 20min logging) in the epilimnion (0.2m) and revealed distinct diel water quality cycling of temperature, dissolved oxygen and pH (conductivity represented freshwater wetlands), which was more obvious in the late-dry season survey because of extreme summer conditions. Water quality varied among wetlands in terms of the daily amplitude and extent of daily photosynthesis recovery, which highlights the need to consider local conditions and that applying general assumptions around water quality conditions for these types of wetlands is problematic for managers. Though many fish access wetlands during wet season connection, the seasonal effect of reduced water level conditions seems more over-improvised when compared to whether fences are installed, as all wetlands supported few, juvenile, or no fish species because they had dried completely regardless of the presence of fences.

The influence of surrounding land cover on wetland habitat conditions: a case study of inland wetlands in South Korea

Wetland ecosystems have been globally degraded and lost due to rapid urbanization and climate change. An assessment of national scale inventory, including wetland types and conditions, is urgently required to understand the big picture of endangered wetlands, such as where they are and how they look like. We analyzed the spatial patterns of each inland wetland type (brackish wetland was included) in South Korea and the relative importance of land cover categories on wetland conditions. The wetlands were grouped into four dominant types (riverine, lake, mountain, and human-made) according to their topography. Riverine wetlands constituted the largest area (71.3%). The relative ratio of wetlands in a well-conserved condition (i.e., “A” rank) was highest in riverine wetlands (23.8%), followed by mountain wetlands (22.1%). The higher proportion of grasslands was related to a better condition ranking, but the increasing bareland area had a negative impact on wetland conditions. We also found that wetlands located near wetland protected areas tend to be in a better condition compared to remote sites. Our results further support the importance of the condition of surrounding areas for wetland conservation.