Range Of Habitat Preferences Research Articles

Response of macroinvertebrate communities to seasonal hydrologic changes in three sub-tropical Australian streams

In the Australian sub-tropics, seasonal changes in hydrology can influence abiotic conditions, and consequently, the biota. Several methods of macroinvertebrate analyses, including the use of taxonomic groupings, are used to ascertain information regarding stream biodiversity and health. The use of biological traits to group and analyse macroinvertebrate communities, however, may provide a better picture of stream health, particularly in ephemeral streams. To address whether this is the case, three ephemeral systems in the lower Fitzroy catchment, Central Queensland, Australia, were studied over an 18-month period. A total of 69 macroinvertebrate families from 14 orders were collected in 128 samples. Taxonomic analysis indicated there was a range of habitat preferences within groups characterized by a large proportion of tolerant and generalist taxa. The macroinvertebrate communities were categorised into biological trait groups, with a number of predator families found during all flow regimes. A general pattern of Gatherer > Predator > Grazer > Shredder > Filterer was observed. This study provides a clear pattern of the biological traits present during variable flow and could be used as a framework for future stream health modelling. A trait-specific management tool for assessing freshwaters has not yet been adopted in global management protocols and would require both a more definitive understanding of patterns during different flow periods and an internationally recognised set of trait nomenclature.

Positive effects of burning and cattle grazing on grasshopper diversity

Abstract Grasshoppers constitute a significant proportion of invertebrate diversity in grasslands, but little is known about how fire and grazing, two of the main drivers of grassland dynamics, influence them. Here, we determine how these disturbances influence grasshopper diversity in remnant grassland ecological networks (ENs) among commercial forestry compartments in Afromontane grassland, South Africa. Sites differed in fire frequency (annual vs. longer rotation burning), time since last fire (<12 months vs. >12 months ago), and presence or absence of domestic cattle grazing. Reference sites were in an adjacent protected area (PA). We also recorded bare ground, vegetation cover, and vegetation height. Grasshopper abundance significantly benefitted from annual burning, cattle grazing, short grass, and when the last fire was <12 months prior to sampling. Fire frequency was the only disturbance with a significant effect on grasshopper species composition, but without significantly affecting species richness. In the PA, heterogeneity of dispersion was smaller in annually burned firebreaks than in sites with longer fire‐return intervals, which points to homogenisation of resident grasshopper assemblages. Although most grasshopper species favoured recently burned or grazed grassland, some preferred low or no disturbance. This illustrates a considerable range of habitat preferences in the grasshopper assemblage. Management recommendation: Burning and grazing at moderate levels should be integral to local landscape management, as these impacts benefit grasshoppers in grassland ENs. Some areas should be left undisturbed to create a mosaic of different successional stages at the landscape spatial scale, providing diverse habitat for a wide range of species.