Non-riparian Habitats Research Articles

Diversity of arboreal ants in several types of land use in the Harapan Forest Landscape, Jambi

The forest area in Jambi remains at 17.25%, while the area of rubber and oil palm plantations reaches 35.54% of Jambi’s total area. Habitat transformation can reduce insect diversity and their ecosystem services. This study aims to analyze the effect of deforestation on the diversity and abundance of arboreal ants in the Harapan Forest landscape. Sampling was carried out from June to August 2017 using the fogging method. The identification was carried out at the Laboratory of Biological Control, Department of Plant Protection, IPB University, from October 2021 to August 2022. Data analysis using R studio vegan and ggplot2 packages. The results showed that the highest abundance of arboreal ants was found in the forest, with an abundance of 3106 individuals. The lowest was in the rubber plantation, with an abundance of 229 individuals. The highest arboreal ant richness was found in the riparian forest with 33 genera, and the lowest arboreal ant richness was found in rubber plantations with 16 genera. It was concluded that deforestation caused a decrease in the abundance and richness of arboreal ants, for riparian and non-riparian habitats for each land use had no significant effect on the abundance and richness of arboreal ants.

Potential drivers of common brushtail possum (

Australia’s terrestrial mammalian fauna have experienced severe declines since European settlement. On the Murray–Darling floodplain in south-eastern Australia, common brushtail possums (Trichosurus vulpecula, ‘possums’), have contracted to riparian zones. Although an important possum refuge, little is known about possum population dynamics here. We examined possum population dynamics and potential drivers across two decades on the Murray River floodplain at Calperum Station. We related possum density to satellite derived fractional cover, (a measure of the proportion of green, non-green and bare ground cover), and contextualised these findings using tree condition and grazing pressure datasets. Possum surveys were conducted between 1998 and 2019 in riparian and non-riparian habitats and density was modelled in relation to fractional cover values of green, non-green, and bare ground. Possum density fluctuated between 1998 and 2008 but in 2018 and 2019, possums were undetectable. Possum density was negatively associated with bare ground and positively associated with non-green. Overgrazing by kangaroos likely reduced vegetation cover and diversity and contributed to possum decline, via a reduction in possum food resources and increased exposure to predation. Inconsistent monitoring meant that the population decline was not detected until after it had occurred, and management interventions were not triggered, highlighting the dilemma of allocating scarce monitoring resources.

Earlywood Vessels in Black Ash (Fraxinus nigra Marsh.) Trees Show Contrasting Sensitivity to Hydroclimate Variables According to Flood Exposure.

In recent years, the utility of earlywood vessels anatomical characteristics in identifying and reconstructing hydrological conditions has been fully recognized. In riparian ring-porous species, flood rings have been used to identify discrete flood events, and chronologies developed from cross-sectional lumen areas of earlywood vessels have been used to successfully reconstruct seasonal discharge. In contrast, the utility of the earlywood vessel chronologies in non-riparian habitats has been less compelling. No studies have contrasted within species their earlywood vessel anatomical characteristics, specifically from trees that are inversely exposed to flooding. In this study, earlywood vessel and ring-width chronologies were compared between flooded and non-flooded control Fraxinus nigra trees. The association between chronologies and hydroclimate variables was also assessed. Fraxinus nigra trees from both settings shared similar mean tree-ring width but floodplain trees did produce, on average, thicker earlywood. Vessel chronologies from the floodplain trees generally recorded higher mean sensitivity (standard deviation) and lower autocorrelation than corresponding control chronologies indicating higher year-to-year variations. Principal components analysis (PCA) revealed that control and floodplain chronologies shared little variance indicating habitat-specific signals. At the habitat level, the PCA indicated that vessel characteristics were strongly associated with tree-ring width descriptors in control trees whereas, in floodplain trees, they were decoupled from the width. The most striking difference found between flood exposures related to the chronologies' associations with hydroclimatic variables. Floodplain vessel chronologies were strongly associated with climate variables modulating spring-flood conditions as well as with spring discharge whereas control ones showed weaker and few consistent correlations. Our results illustrated how spring flood conditions modulate earlywood vessel plasticity. In floodplain F. nigra trees, the use of earlywood vessel characteristics could potentially be extended to assess and/or mitigate anthropogenic modifications of hydrological regimes. In absence of major recurring environmental stressors like spring flooding, our results support the idea that the production of continuous earlywood vessel chronologies may be of limited utility in dendroclimatology.

Riparian thermal conditions across a mixed rural and urban landscape

Riparian corridors have the potential to function as thermal refuges, moderating extremes of local temperature variation. However, although demonstrated at individual sites, and over short periods, the consistency of this effect at wider temporal and spatial scales is poorly understood. The aim of this study is to assess the temperature differences between riparian corridors and adjacent non-riparian habitats and to explore the influence of environmental characteristics on these differences. Air temperature was monitored hourly at 20 paired locations (riparian and non-riparian) for two consecutive years. Urban index and canopy cover were characterised by calculating the percentage of impervious surface area and tree canopy cover within a 100 m radius from the centre of each sampling site. Canopy cover reduced summer thermal stresses in both urban and rural areas whereas high urban index tended to increase the daily thermal indices. Rivers had a significant mitigating effect on the urban riparian thermal condition, particularly in extreme hot weather. Riparian corridors were generally 1 °C cooler than non-riparian locations in summer and could be up to 3 °C cooler at some sites in extreme hot weather. Furthermore, riparian corridors at some sites were warmer than non-riparian locations in winter. These findings suggest that the proximity of rivers can modify riparian thermal environments, potentially reducing the heat stress of riparian corridors across landscapes.

The width of riparian habitats for understory birds in an Amazonian forest

Riparian habitats are important for the maintenance of regional biodiversity. Many studies have compared bird distributions between riparian and non-riparian habitats but have not established how wide riparian habitats used by birds are, as measured by distance from the nearest stream. We investigated the distribution of understory birds along gradients of distance from streams, soil clay content, and slope in a central Amazonian forest, by mist-netting birds three times in 45 plots. We used nonmetric multidimensional scaling (NMDS) to reduce the dimensionality of species quantitative (abundance) and qualitative (presence-absence) composition to one multivariate axis. Estimates of the width of riparian habitats as indicated by understory birds depended on the community attribute considered, measuring 90 m for species quantitative composition and 140 m for species qualitative composition. Species distributions were correlated with clay content but were independent of slope, while distance from streams was positively correlated with clay content but independent of slope. Clay content affects plant species composition, which in turn, may influence bird species composition. However, distribution patterns of birds in relation to distance from streams are consistent among studies carried out in many different temperate and tropical regions, indicating an effect of distance from streams itself. Protection of riparian habitats is one of the most widely used conservation strategies, and Brazilian environmental legislation mandates the protection of a 30 m wide strip of riparian vegetation on either side of small streams. We show that the protected strip should be much wider and recommend strategies to place other forms of land protection contiguous with riparian areas so that Brazilian environmental legislation better fulfills its role of protecting biodiversity associated with riparian habitats.

Comparative Study of Forest-Dwelling Bats' Abundances and Species Richness between Old-Growth Forests and Conifer Plantations in Nikko National Park, Central Japan

Abstract. To determine the influence of the forest type on bats in terms of roosting sites and foraging habitats, we compared species richness and abundance (total and by species) of forest-dwelling bats in old-growth forests and conifer (larch) plantations in central Japan. We also compared species richness and abundance of the bats in riparian and non-riparian habitats, and compared the old-growth forest stands with the larch plantation stands to examine differences in the forest stand structures. Species richness, total bat abundance, and the abundances of two tree-roosting specialists, the Ikonnikovi's Myotis (Myotis ikonnikovi) and the Ussurian tube-nosed bat (Murina ussuriensis), were significantly higher in the old-growth forests than in the conifer plantations. The old-growth forests contained larger trees and more snag trees, which provided roosting sites for tree-roosting species. Species richness, total bat abundance, and abundances of the two tree-roosting specialists and the Japanese large-fo...

Invasion impacts on biodiversity: responses of ant communities to infestation by cat’s claw creeper vine, Macfadyena unguis-cati (Bignoniaceae) in subtropical Australia

Ants are the dominant soil faunal group in many if not most terrestrial ecosystems, and play a key role in soil structure and function. This study documents the impacts of invasion by the exotic cat’s claw creeper vine, Macfadyena unguis-cati (L.) Gentry (Bignoniaceae) on surface-situated (epigaeic) and subterranean (hypogaeic) ant communities in subtropical SE Queensland Australia where it is a major environmental weed of riparian areas, rainforest communities and remnant natural vegetation, smothering standing vegetation and causing canopy collapse. Soil ants were sampled in infested and uninfested areas at eight sites spanning both riparian and non-riparian habitats in subtropical SE Queensland. Patterns of ant species composition and functional grouping in response to patch invasion status, landscape type and habitat stratum were investigated using ANOVA and non-metric multidimensional scaling ordination. The epigaeic and subterranean strata supported markedly different ant assemblages, and ant communities also differed between riparian and non-riparian habitats. However, M. unguis-cati invasion had a surprisingly limited impact. There was a tendency for ant abundance and species richness to be lower in infested patches, and overall species composition was different between infested and uninfested patches, but these differences were relatively small, and did not occur consistently across sites. There were changes in functional group composition that conformed to known functional group responses to environmental change, but these were similarly limited and inconsistent across sites. Our study has shown that ant communities are surprisingly resilient to invasion by M. unguis-cati, and serves as a warning against making assumptions about invasion impacts based on visual appearances.

Comparisons in water relations of plants between newly formed riparian and non-riparian habitats along the bank of Three Gorges Reservoir, China

The water table in the Three Gorges Reservoir (TGR) rose significantly since the construction of the Three Gorges Dam across the Yangtze River. Little is known about how such a change in local hydrological condition will affect the ecophysiology of plants along the bank of the world’s largest reservoir. In this study, water relations of the dominant plants were investigated over an entire year period by comparing stable isotope compositions of xylem water, leaf water potentials and foliar carbon isotope ratios at a newly-formed riparian site near the river bank and two non-riparian sites at higher elevations. The isotopic compositions of xylem water indicated that the plants in the newly-formed riparian zone acquired water mainly from the soil previously infiltrated by local rain rather than the Yangtze River water. Predawn and midday water potentials of the riparian trees were also similar to those at the non-riparian sites. Leaf δ13C values of plants across the three sites also showed no difference, even though there was a significant difference among species. Our results indicate that plants at the newly formed transient riparian area along the bank of TGR do not depend on the Yangtze River water for their water sources and that rising water levels in this reservoir may not lead to immediate changes in water relations of the plants along the bank.

STOPOVER ECOLOGY OF AUTUMN LANDBIRD MIGRANTS IN THE BOISE FOOTHILLS OF SOUTHWESTERN IDAHO

The topography of western North America provides a complex landscape for landbird migrants, and stopover patterns in this region are poorly understood. We examined seven years of stopover data (1997-2003) from a montane area in southwestern Idaho to determine whether this area provides suitable stopover habitat. We compared the proportion of birds recaptured, stopover duration, and changes in energetic condition within and among species and between two mist-netting sites located in different habitats. The proportion of birds recaptured ranged from zero to over 20%, and fewer than 5% of individuals were recaptured in most species. Mean minimum stopover durations from recapture data ranged from 1 to 10 days; most species averaged less than 6 days. Stopover duration estimates from open-population models were comparable but generally greater than estimates from recapture data. As found in stopover studies from other regions, stopover metrics varied within and among species in Idaho. However, most migrants in this study exhibited an ability to gain mass, evidenced both by recapture data and by regression of energetic condition against time since sunrise. These data imply that montane habitats in Idaho are suitable stopover sites. It follows that these habitats might serve an important role for many landbird migrants during the period of late summer molt and autumn migration, a time when many lowland areas of the West, including some riparian systems, are especially arid. We suggest that including montane nonriparian habitats in future stopover ecology studies will allow for a more complete understanding of migrant habitat needs in the West.

The use of riparian forest strips by small mammals in a boreal balsam fir forest

Because riparian forest strips are perceived to buffer aquatic ecosystems from logging-related disturbance, they are usually not harvested. However, their value as refuges for terrestrial wildlife is unknown. We conducted two live-trapping experiments in the riparian zone adjacent to rivers in a boreal balsam fir ( Abies balsamea) forest in Quebec. In the first experiment, we compared late summer use, during 4 separate years, of different width riparian strips (20, 40, 60 m, and control [>300 m wide]), and different stand thinning intensities (20 m intact and 20 m thinned of 1 3 of all trees) on resident small mammals. We found no differences in the densities of the most common species, Clethrionomys gapperi and Peromyscus maniculatus, among strip types or among years ( P>0.05). We also tested for edge effects in large strips (60 m and controls). In controls, C. gapperi was less abundant in the first 20 m adjacent to the river ( P=0.004) while P. maniculatus was more abundant ( P=0.02) in that area. Neither species, however, showed an edge effect in the 60 m-strips ( P>0.10). In the second experiment, we monitored small mammals over eight consecutive weeks in a 160 m×170 m quadrat enclosing a 20 m-thinned forest strip and a clear-cut to investigate some aspects of the role of riparian strips at the landscape scale. During that time, Microtus pennsylvanicus, which was nearly absent from our study area in the previous years, invaded the clear-cuts and apparently confined C. gapperi and P. maniculatus to forest remnants such as 20 m-wide strips. A conclusion that emerges from this study and related studies on birds is that some species prefer larger strips or non-riparian habitats whereas others prefer narrow strips along riparian habitats. We recommend that managers ban the all-encompassing norms and manage for heterogeneity at different scales. Because our study was conducted at the stand scale and because it is not accompanied with an evaluation of the socio-economic aspects of riparian management, we cannot determine the proper mixture of strips in the landscape. However, our results could help managers to enhance the key-role of riparian ecosystems in maintaining regional biodiversity and contribute to the maintenance of local biodiversity by creating refuges for terrestrial wildlife.

Relative value of riparian woodlands in landscapes with different forest cover for medium-sized Iberian carnivores

This study analyses the role of riparian woodland in the conservation of five common carnivore species as compared with other non-riparian habitats according to woodland cover on the landscape scale (>60, 20–35 and <15% on 20 × 20-km surface area). I hypothesised that the importance of riparian woodlands in carnivore conservation on the regional scale would be greater in landscapes with low forest cover than in those with intermediate or high forest cover. To test this hypothesis, in each landscape type I sampled five riparian forests and 10–15 non-riparian habitats and recorded species richness and frequency of occurrence (number of sampled sites with species presence/total sampled sites) in both habitat types. The presence of (or use by) species at each particular sampling site was recorded using sign-surveys (search for scats and badger dens). The relative importance of riparian and non-riparian habitats in each landscape type was analysed by comparing species richness and frequency of occurrence for each species. Comparison of species richness and frequency of occurrence between landscape types indicate that riparian woodlands are important habitats in all landscape contexts. However, in accordance with the initial hypothesis, riparian woodlands are essential for carnivore conservation in the most deforested areas. Any agricultural or development policy should take into account the need to maintain and preserve riparian woodlands in landscapes, especially in intensively cultivated landscapes.

Breeding bird assemblages associated with riparian, interior forest, and nonriparian edge habitats in a balsam fir ecosystem

Breeding bird assemblages associated with riparian, interior forest, and nonriparian edge habitats in a balsam fir ecosystem

The Influence of Riparian and Adjacent Habitats on Small Mammal Distributions in Grand Teton National Park, Wyoming

Riparian ecosystems are among the most productive biological systems providing food, water, shade, and cover for wildlife (Thomas et al. 1979). Furthermore, they may display a greater diversity of plant and animal species and vegetative structure than adjacent ecosystems (USDI 1986). Previous investigators have sought to document rodent associations within riparian vegetation (Moor and Bradley 1975, Anderson et al. 1977, Boeer and Schmidly 1977, Gier and Best 1980, Paul 1981, Cross 1985, Doyle 1986, 1990, MacCraken et al. 1985, Anthony et al. 1987). Generally, these studies demonstrate that riparian habitats contain higher abundance and lower diversity of small mammal species when compared to adjacent upland sites or nearby sites which contained variable non-riparian habitats. Odum (1978) states that for wildlife populations, the riparian zone provides a classic example of the ecological pririciple of "edge effect". This effect is exerted by adjoining communities on the population structure within the ecotone which often contains greater numbers of species and higher densities of some species then either adjoining communities. He further states that density and diversity of species tend to be higher at the land-water ecotone than in adjacent communities. This relationship between edge effect and wildlife has not been well documented (Forman and Godron 1986) in part, because research has focused more on induced edges created by corridors than by patches (Yahner 1988).