Search

© 2014 Elsevier Ltd. Land surface phenology (LSP) characterizes episodes of greening and browning of the vegetated land surface from remote sensing imagery. LSP is of interest for quantification and monitoring of crop yield, wildfire fuel accumulation, vegetation condition, ecosystem response and resilience to climate variability and change. Deriving LSP represents an effort for end users and existing global products may not accommodate conditions in Australia, a country with a dry climate and high rainfall variability. To fill this information gap we developed the Australian LSP Product in contribution to AusCover/Terrestrial Ecosystem Research Network (TERN).We describe the product's algorithm and information content consisting of metrics that characterize LSP greening and browning episodes of the vegetated land surface. Our product allows tracking LSP metrics over time and thereby quantifying inter- and intraannual variability across Australia. We demonstrate the metrics' response to ENSO-driven climate variability. Lastly, we discuss known limitations of the current product and future development plans.

Recent literature suggests that the initial concept of two contrasting ecological regimes (macrophyte or phytoplanktondominated) in nutrient-enriched shallow lakes should be extended, based on observations that such systems may be dominated by free-floating plants, submerged charophytes, submerged angiosperms, green algae or cyanobacteria at different points along a gradient of eutrophication. The implications of this for management and restoration are that different levels or thresholds of a controlling variable (such as nutrients) may be necessary to cause a shift in dominance depending on the characteristics of the dominant taxa. Each of the plant types listed above occur simultaneously in spring in different locations in the Vasse Wonnerup Estuary. This paper explores the drivers for dominance of different plant communities in these shallow waterbodies, focussing on potential thresholds (particularly total phosphorus concentrations and N:P ratios), that might explain the efficacy of nutrient reduction measures, the likelihood of catastrophic loss of macrophytes from the wetlands or guide restoration of macrophytes in currently phytoplankton-dominated systems.

Emergent plants can be suitable indicators of anthropogenic stress in coastal wetlands if their responses to natural environmental variation can be parsed from their responses to human activities in and around wetlands. We used hierarchical partitioning to evaluate the independent influence of geomorphology, geography, and anthropogenic stress on common wetland plants of the U.S. Great Lakes coast and developed multi-taxa models indicating wetland condition. A seven-taxon model predicted condition relative to watershed-derived anthropogenic stress, and a four-taxon model predicted condition relative to within-wetland anthropogenic stressors that modified hydrology. The Great Lake on which the wetlands occurred explained an average of about half the variation in species cover, and subdividing the data by lake allowed us to remove that source of variation. We developed lake-specific multi-taxa models for all of the Great Lakes except Lake Ontario, which had no plant species with significant independent effects of anthropogenic stress. Plant responses were both positive (increasing cover with stress) and negative (decreasing cover with stress), and plant taxa incorporated into the lake-specific models differed by Great Lake. The resulting models require information on only a few taxa, rather than all plant species within a wetland, making them easier to implement than existing indicators.

Plant taxa identified in 90 U.S. Great Lakes coastal emergent wetlands were evaluated as indicators of physical environment. Canonical correspondence analysis using the 40 most common taxa showed that water depth and tussock height explained the greatest amount of species-environment interaction among ten environmental factors measured as continuous variables (water depth, tussock height, latitude, longitude, and six ground cover categories). Indicator species analysis was used to identify species-environment interactions with categorical variables of soil type (sand, silt, clay, organic) and hydrogeomorphic type (Open-Coast Wetlands, River-Influenced Wetlands, Protected Wetlands). Of the 169 taxa that occurred in a minimum of four study sites and ten plots, 48 were hydrogeomorphic indicators and 90 were soil indicators. Most indicators of Protected Wetlands were bog and fen species which were also organic soil indicators. Protected Wetlands had significantly greater average coefficient of conservatism (C) values than did Open-Coast Wetlands and River-Influenced Wetlands, but average C values did not differ significantly by soil type. Open-Coast and River-Influenced hydrogeomorphic types tended to have sand or silt soils. Clay soils were found primarily in areas with Quaternary glaciolacustrine deposits or clay-rich tills. A fuller understanding of how the physical environment influences plant species distribution will improve our ability to detect the response of wetland vegetation to anthropogenic activities.

We present the distribution and aquatic habitat use of amphibian communities in two river basins of Transylvania (Romania) on a medium spatial scale: the middle section of Târnava Mare Valley and the Upper section of the Olt Valley. We used between 13 and 15 variables to characterize the breeding ponds and their surrounding terrestrial areas. A total number of 14 amphibian species and a species complex were identified in the two areas. In Târnava, the average species richness is larger in permanent ponds than in temporary ones. No significant differences were found between the species richness in permanent and temporary ponds in Ciuc. In permanent ponds of both areas the presence of high traffic roads in the vicinity (i.e. within an 800 m radius) explained more of the variation in species richness than the other habitat factors, whereas the presence of dirt roads accounted for the highest variation in species richness in temporary ponds.