Conservation Of Riparian Forests Research Articles

Multiple dimensions of phyllostomid bat biodiversity across ecosystems of the Orinoco Llanos

AbstractUnderstanding the impacts of habitat conversion on species assemblages across multiple biodiversity dimensions (taxonomic, functional, and phylogenetic) and spatial scales is pivotal for implementing effective conservation strategies. Here, we surveyed phyllostomid bats using mist nets in riparian and unflooded forests, flooded savannahs, and conventional rice fields to investigate how changes in habitat quality affect multifaceted diversity from two Colombian farming systems in the Orinoco Llanos: traditional farmlands with high‐intensity agriculture (mainly rice production) and Civil Society Nature Reserves with greater ecosystem protection. We used a unified framework based on Hill numbers for quantifying bat taxonomic, functional, and phylogenetic diversity and modeled the relationship of these diversity facets with landscape variables (habitat cover and patch density) across three spatial scales (0.5, 1.5, 3 km) using Bayesian generalized linear mixed‐effect models. Our results indicate that increasing human activity toward rice monocultures representative of traditional farmlands negatively affected all diversity facets. In contrast, forested habitats associated mainly with riparian forests within private reserves contained higher taxonomic, functional, and phylogenetic diversity than savannahs and rice fields. However, the differences between riparian forests and rice crops were significant only for phylogenetic diversity, indicating loss of evolutionary history after habitat conversion. At the landscape scale, forest cover was a significant predictor for functional (0.5‐ and 3‐km scale) and phylogenetic diversity (0.5 km), and bats responded negatively at the 3‐km scale to rice patch density from a functional diversity perspective. Increasing habitat quality through preserving forest cover and patches should minimize the harmful effects of habitat conversion on multidimensional bat biodiversity. Furthermore, the conservation of riparian forests and the creation of more wildlife‐friendly farming, as practiced in the reserves, should be prioritized to ensure high levels of bat taxonomic, functional, and phylogenetic diversity across Orinoco countryside landscapes.

Freshwater salinization syndrome limits management efforts to improve water quality.

Freshwater Salinization Syndrome (FSS) refers to groups of biological, physical, and chemical impacts which commonly occur together in response to salinization. FSS can be assessed by the mobilization of chemical mixtures, termed "chemical cocktails", in watersheds. Currently, we do not know if salinization and mobilization of chemical cocktails along streams can be mitigated or reversed using restoration and conservation strategies. We investigated 1) the formation of chemical cocktails temporally and spatially along streams experiencing different levels of restoration and riparian forest conservation and 2) the potential for attenuation of chemical cocktails and salt ions along flowpaths through conservation and restoration areas. We monitored high-frequency temporal and longitudinal changes in streamwater chemistry in response to different pollution events (i.e., road salt, stormwater runoff, wastewater effluent, and baseflow conditions) and several types of watershed management or conservation efforts in six urban watersheds in the Chesapeake Bay watershed. Principal component analysis (PCA) indicates that chemical cocktails which formed along flowpaths (i.e., permanent reaches of a stream) varied due to pollution events. In response to winter road salt applications, the chemical cocktails were enriched in salts and metals (e.g., Na+, Mn, and Cu). During most baseflow and stormflow conditions, chemical cocktails were less enriched in salt ions and trace metals. Downstream attenuation of salt ions occurred during baseflow and stormflow conditions along flowpaths through regional parks, stream-floodplain restorations, and a national park. Conversely, chemical mixtures of salt ions and metals, which formed in response to multiple road salt applications or prolonged road salt exposure, did not show patterns of rapid attenuation downstream. Multiple linear regression was used to investigate variables that influence changes in chemical cocktails along flowpaths. Attenuation and dilution of salt ions and chemical cocktails along stream flowpaths was significantly related to riparian forest buffer width, types of salt pollution, and distance downstream. Although salt ions and chemical cocktails can be attenuated and diluted in response to conservation and restoration efforts at lower concentration ranges, there can be limitations in attenuation during road salt events, particularly if storm drains bypass riparian buffers.

Urban Gardens’ Potential to Improve Stormwater Management: A Comparative Analysis among Urban Soils in Sorocaba, São Paulo, Brazil

Permeable surfaces are increasingly rare in urban centers, but they have the utmost importance for stormwater infiltration. In this context, green spaces are key to reducing problems caused by runoff. This work aimed to evaluate the physical characteristics of the soil used for agroecological gardening, in comparison with parks, wasteland, and riparian forest in Sorocaba, São Paulo, Brazil. During the one-year data collection, urban gardens were superior to other areas in hydraulic conductivity (35.8 mm h−1), humidity (25.8%), and soil penetration resistance (1.21 MPa). On the other hand, the riparian forest showed signs of soil degradation, with low water infiltration rates (121.9 mm h−1) and humidity (14.4%). These findings highlight the importance of better soil management solutions to avoid compaction, such as the protection and conservation of riparian forests. Furthermore, the encouragement of urban gardens and parks with multiple uses can be an option for the enhancement of stormwater management in cities, since this practice has the potential to improve the physical characteristics of urban soils and provide several ecosystem services.

Vertical Migration of Adult Plecoptera and Trichoptera above Forested Headwater Streams.

Simple SummaryStream insects are essential components of aquatic and terrestrial ecosystems, but fewer studies have examined the terrestrial stage compared to the aquatic stage. Most adult stream insects are flight capable, which allows for short- and long-distance movements away from the stream channel into riparian or upland habitats. This study examined if adult stream insects migrate vertically into riparian forest canopies above the stream. We found a meaningful number of adult Trichoptera and Plecoptera in the forest canopy above the stream that was comparable to horizontal migrations. This result demonstrated that adult stream insects utilize riparian forest canopies and that numerous avenues for additional basic and applied research on terrestrial–aquatic linkages exist. Discovering how riparian canopy habitats are important for stream insects and how stream insects are linked to canopy ecosystems can inform restoration and conservation actions.Stream insects are essential components of aquatic and terrestrial ecosystem structure and function. Terrestrial stages are important components of terrestrial food webs, and flight-capable individuals are responsible for long-distance dispersal. Horizontal migrations by flying or crawling adults away from stream channels that link insects to riparian food webs and movements across catchment boundaries are well established through empirical research, but studies examining vertical migration of adult stream insects into forest canopies are generally lacking. This study focused on differences in adult Plecoptera and Trichoptera abundance at ground level versus the riparian canopy and differences in abundances among summer and autumn sampling periods to empirically demonstrate use of canopy ecosystems by stream insects. Malaise traps at ground level and canopy traps placed 8 to 10 m above the stream at four sites in the Mosquito Creek watershed (Pennsylvania) were used to examine vertical migration. Larval assemblages were collected and compared to adult assemblage to investigate patterns of local migration in the catchment. We found significantly more stream insects at ground level than in the forest canopy for Trichoptera, Plecoptera, and all individual plecopteran families, but a meaningful number of individuals were found in the riparian canopy. Canopy abundances were similar to abundances captured in adjacent ground-level habitats in other studies. Comparisons of adult and larval abundances among sites, taxa, and stages indicated site- and taxon-specific patterns for vertical movement into riparian canopies. Demonstrating that adult stream insects utilize riparian forest canopies indicates that riparian forest conservation should be prioritized over reforestation and that several potential research questions exist to inform riparian management.

Agricultural Impacts on Hydrobiogeochemical Cycling in the Amazon: Is There Any Solution?

Expansion of agriculture in the Brazilian Amazon has been driven not just by demands from traditional, rural producers, but also large agriculture and cattle producers, both of whom have put considerable pressure on remaining forests and their watersheds. Monitoring of these watersheds has been a focus of intensive study for the past 20 years and although this work has greatly increased our understanding, considerable gaps still remain in our ability to provide adequate recommendations for land management and associated public policies. In this study we present a summary of findings from these previous results. For small properties, the use of fire to prepare land for cultivation remains controversial, while in large properties, forest conversion to pasture and/or crop production has had a meaningful and adverse effect on water quality. Riparian forest conservation can make a significant difference in reducing impacts of land-use change. Secondary vegetation can also play an important role in mitigating these impacts. New types of sustainable agricultural production systems, together with incentives such as payments for ecosystem service can also contribute. Continued monitoring of these changes, together with robust sustainable development plans, can help to preserve forest while still addressing the social and economic needs of Amazonian riverine inhabitants.

The negative influences of the new brazilian forest code on the conservation of riparian forests

AbstractMore than one million hectares of riparian forests were degraded or altered in Mato Grosso State (Brazil) up to 2009. The aim of the research is to set a comparative scenario to show differences in the quantification of environmental liabilities in riparian forest areas resulting from the change in native vegetation protection rules due to the transition between Laws 4771/65 and 12651/2012. Data collection took place in a marginal stretch of Vermelho River in Rondonópolis County, Mato Grosso State. The following data set was taken into consideration: aerial images derived from unmanned aerial vehicle, Rapid Eye satellite images and orbital images hosted at Google Earth. The spatial resolution of those images was compared. The aerial photos composed a mosaic that was photo-interpreted to generate land use and occupation classes. The riparian forest areas of a rural property were used as parameter, and their environmental situation was compared in 05 meter and 100 meter strips. Thus, by taking into consideration the current rules, 23,501 m2of area ceased to be an environmental liability within the riparian forest and became a consolidated rural area. According to the previous Forest Code, in a different scenario, that is, in a set of rural properties, the public authority would receive USD 68,600.00 in fines. The new Brazilian Forestry Code of 2012, which replaces the previous one made in 1965, exempts those responsible for rural property from regenerating previously deforested native vegetation - an obligation established by older Forest Code. We have shown that the new Forest Code has diminished the legal responsibility of the rural owners in relation to the maintenance of forest fragments in their properties.

Satisfying rival forestry objectives in the Komi Republic: effects of Russian zoning policy change on wood production and riparian forest conservation

Spatial segregation of different forest landscape functions can accommodate rival forestry objectives more comprehensively than integrated approaches. Russia has a unique history of forest zoning separating production and environmental functions. However, the Russian Forest Code of 2006 increased the focus on wood production. We reviewed the history of zoning policy in Russia and assessed if the recent policy change affected logging rates and conservation of riparian forests. Using Russia’s Komi Republic as a case study, we specifically assessed (i) if policy change led to increased logging near streams, (ii) if logging rates were different in headwaters vs. main rivers, and (iii) how logging changed among catchments with different accessibility to logging. Using a global open-access remote sensing dataset, we compared mean annual forest loss as a proxy of logging rates in 10 large forested catchments in the Komi Republic in one period with strict zoning policy (2000–2006) and one with moderate zoning policy (2007–2014). Harvesting rate was positively related to the distance from streams. On the other hand, it increased after the policy change in the buffer zone but decreased outside it. Forests were harvested more in headwater buffers than along larger rivers, and harvest in the catchments near industries was higher and increasing; remote catchments had low forest loss. We discuss the opportunity for adopting forest zoning policy in different governance contexts.

Influences Des Zones Biogéographiques Sur La Diversité Avienne Des Galeries Forestières Au Bénin, Afrique De l’Ouest

This study examined the diversity and ecological distribution of riparian bird species across a climatic gradient in Benin. Riparian bird communities were compared among three climatic zones in Benin Republic from December 2012 to November 2015. The diversity and ecological distribution of riparian bird was examined from a census (inventory) of birds in forests galleries across the three climatic zones in Benin by means of a technique of sampling of limited (punctual) type centred on no listening of 20 minutes in a circular plot of 18 m of beam. A total of 140 species richness belonging to 18 orders and 44 families were recorded across climatic zones. The highest (73) species richness were recorded in Guinean zone, followed by Soudanean zone (70) and Soudano – guinean zones, the lowest (68). Similarly, species diversity was highest in Soudanean zone (H’=5.77 bits) and lowest in Soudano – guinean zone (4,28 bits). But we have a significant difference in species diversity between the study climatic zones, but relative abundance of bird are not differed between zones. Further, diverse bird guilds were recorded varying across the climatic gradients indicating the riparian forest conservation importance. Increasing farmland severs more suitable habitats with dire consequences on the survival of disturbance – sensitive bird species. These researches underpin the need for considering integrated bird conservation strategies and are important for planning local ecotourism activities and to protect riparian forest in Benin.

Functional patterns and species diversity of epiphytic vascular spore-producing plants in riparian forests with different vegetation structure from southern Brazil

Background and aims Functional patterns and the environmental influence over species traits are important tools for the conservation of riparian forests. Richness, diversity and functional structure

Nest site characteristics of the Great-spotted Woodpecker in a bottomland riparian forest in the presence of invasive tree species

Abstract This study was carried out in Hungary, in an old unmanaged riparian poplar-willow forest during the breeding seasons of 2014 and 2015. The occurrence of two invasive tree species, the green ash and boxelder, is significant in the study area, which influences negatively the populations of native riparian tree species in Central Europe. We studied Great-spotted Woodpecker nest sites in the presence of these invasive species. Throughout the study period, eight and twelve nesting cavity trees were mapped. Trees were recorded in 20-20 circular plots of 0.05 ha both for each mapped nest trees and random plots as well. Species, diameter at breast height and condition were recorded for each tree. Composition and diversity of nest site and random plots were compared. Distributions and preferences were calculated for nest tree use. Most of the recorded trees were invasive. Nest site plots had more native trees compared to random plots. Nest site showed higher diversity in terms of all three variables. Decayed and dead willow and white poplar hybrid trees were preferred for nesting. Diameter at breast height of nest trees was between 30-90 cm. Studies about cavity excavators in transformed habitats have high importance for nature conservation of riparian forests.

Shifts in attributes along agriculture-forest transitions of two streams in central Ohio, USA

Riparian forests are strongly linked to stream ecosystems, and the creation and/or conservation of riparian forests can mitigate the influence of agriculture on streams. Although riparian forest buffers are commonly advocated as best management practices, the extent of forest necessary to effectively mitigate upstream agricultural effects on streams remains unresolved. To determine how soon agricultural streams exhibit detectable effects after entering forest fragments, we surveyed sixteen sites distributed across two 2nd-order headwater streams in agricultural landscapes of central Ohio that exhibit abrupt transitions as they flow from upstream agricultural land up to 1km into downstream forest fragments. Along these transitions we measured leaf-colonizing benthic macroinvertebrate assemblages, leaf-litter breakdown, and physicochemical habitat. Our results indicated that forest fragments can rapidly alter physicochemical and biological attributes of agricultural streams. At both study streams, daily maximum temperature declined within the first 200m of entering forest fragments. Changes in water quality were more variable, but there was evidence of a strong decline in NO3–N along an agriculture-forest transition. There was also evidence of a decline in fine sediment with distance into the forest at one stream. Aquatic macroinvertebrate assemblages exhibited strong changes in composition ranging from the forest edge up to 324m into forest fragments. Taxa that declined after entering forests were generally more tolerant of anthropogenic disturbance and/or those that rely on in-stream primary productivity (i.e., scrapers) whereas most of the taxa that increased after entering forests were relatively sensitive to disturbance and rely on allochthonous organic matter inputs from the forest (i.e., shredders). Collectively, the rapid changes in biological and physicochemical attributes that we observed suggest that even relatively small forest fragments may be able to markedly influence impaired streams and that conservation and restoration of small, discontinuous forest fragments may be important for maintaining stream ecosystem integrity in agricultural landscapes.

The width and biotic integrity of riparian forests affect richness, abundance, and composition of bird communities

In riparian forests, width contributes most importantly to maximizing diversity. Therefore, corridors with different widths should differ in richness, abundance, and composition. We tested this hypothesis for the bird communities of two forests on the Upper Paraná River floodplain, Paraná, Brazil. Richness and abundance were higher in riparian forest with mean width of 50 m in each margin and lower anthropogenic disturbance. Species diversity increased 30%, with increase in total width from 40 m to 100 m on average. Bird species composition also differed, and groups with the strictest ecological requirements were better represented in the wider, better-preserved forest. This indicates that conservation of riparian forests has a positive effect on their bird communities. We suggest that these environments are prioritized for recuperation, and that a 50 m width on each side of a stream is necessary for riparian forests to effectively fulfill their function in the landscape. We also note that the recently discussed Brazilian Forest Code does not conform to this requirement. © 2014 Associação Brasileira de Ciência Ecológica e Conservação. Published by Elsevier Editora Ltda.

Hydrologic thresholds for riparian forest conservation in a regulated large Mediterranean river

AbstractMost riparian trees are phreatophytic, water table‐dependent plants which broadly differ in their tolerance to drought and permanent flooding. In semi‐arid settings, as water is limiting, inundations may be regarded as inputs rather than stresses for the survival of phreatophytes. In this study, the mortality rates and abundances of Populus alba, P. nigra, Salix alba and local Tamarix spp. were examined in 43 plots with different hydrologic conditions distributed across the floodplain of a large semi‐arid and Mediterranean river, the Ebro River (Spain). The objectives were to determine hydrologic thresholds for the maintenance of declining populations of those species, while providing novel information on their phreatophytic nature, and to examine shifts in the species composition along hydrologic gradients. All species exhibited significant relationships between mortality rates and hydrologic variables (deepest water table—WT, flood duration—FD and flood frequency—FF). S. alba was found to be the species with lowest tolerance to drier conditions (hydrologic thresholds for maintaining a mortality rate <50%: WT > −1.22 m; FD: out of observation range; FF > 5.4 events y−1), followed by P. nigra (WT > −2.18 m; FD > 11.1%; FF > 3.8 events y−1), Tamarix spp. (WT > −2.96 m; FD > 3.7%; FF > 2.5 events y−1) and P. alba (WT > −3.45 m; FD > 1.7%; FF > 2.0 events y−1). Only a significant reduction in S. alba relative abundance was observed as conditions got drier. The results provided quantitative information useful to guide management plans for the protection of Mediterranean phreatophytic tree species from further degradation and suggested that eventual natural or regulation‐induced droughts and groundwater declines would accelerate the loss of all phreatophytic species, especially S. alba. Copyright © 2010 John Wiley & Sons, Ltd.

Large Woody Debris Input and Its Influence on Channel Structure in Agricultural Lands of Southeast Brazil

Riparian forests are important for the structure and functioning of stream ecosystems, providing structural components such as large woody debris (LWD). Changes in these forests will cause modifications in the LWD input to streams, affecting their structure. In order to assess the influence of riparian forests changes in LWD supply, 15 catchments (third and fourth order) with riparian forests at different conservation levels were selected for sampling. In each catchment we quantified the abundance, volume and diameter of LWD in stream channels; the number, area and volume of pools formed by LWD and basal area and tree diameter of riparian forest. We found that riparian forests were at a secondary successional stage with predominantly young trees (diameter at breast height <10cm) in all studied streams. Results showed that basal area and diameter of riparian forest differed between the stream groups (forested and non-forested), but tree density did not differ between groups. Differences were also observed in LWD abundance, volume, frequency of LWD pools with subunits and area and volume of LWD pools. LWD diameter, LWD that form pools diameter and frequency of LWD pools without subunits did not differ between stream groups. Regression analyses showed that LWD abundance and volume, and frequency of LWD pools (with and without subunits) were positively related with the proportion of riparian forest. LWD diameter was not correlated to riparian tree diameter. The frequency of LWD pools was correlated to the abundance and volume of LWD, but characteristics of these pools (area and volume) were not correlated to the diameter of LWD that formed the pools. These results show that alterations in riparian forest cause modifications in the LWD abundance and volume in the stream channel, affecting mainly the structural complexity of these ecosystems (reduction in the number and structural characteristics of LWD pools). Our results also demonstrate that riparian forest conservation actions must consider not only its extension, but also successional stage to guarantee the quantity and quality of LWD necessary to enable the structuring of stream channels.

Dams, Floodplain Land Use, and Riparian Forest Conservation in the Semiarid Upper Colorado River Basin, USA

Land and water resource development can independently eliminate riparian plant communities, including Fremont cottonwood forest (CF), a major contributor to ecosystem structure and functioning in semiarid portions of the American Southwest. We tested whether floodplain development was linked to river regulation in the Upper Colorado River Basin (UCRB) by relating the extent of five developed land-cover categories as well as CF and other natural vegetation to catchment reservoir capacity, changes in total annual and annual peak discharge, and overall level of mainstem hydrologic alteration (small, moderate, or large) in 26 fourth-order subbasins. We also asked whether CF appeared to be in jeopardy at a regional level. We classified 51% of the 57,000 ha of alluvial floodplain examined along >2600 km of mainstem rivers as CF and 36% as developed. The proportion developed was unrelated to the level of mainstem hydrologic alteration. The proportion classified as CF was also independent of the level of hydrologic alteration, a result we attribute to confounding effects from development, the presence of time lags, and contrasting effects from flow alteration in different subbasins. Most CF (68% by area) had a sparse canopy (<or=5% cover), and stands with >50% canopy cover occupied <1% of the floodplain in 15 subbasins. We suggest that CF extent in the UCRB will decline markedly in the future, when the old trees on floodplains now disconnected from the river die and large areas change from CF to non-CF categories. Attention at a basinwide scale to the multiple factors affecting cottonwood patch dynamics is needed to assure conservation of these riparian forests.

What is the appropriate paradigm for riparian forest conservation?

Because forest width is thought to be the most relevant metric to ecological communities, it has persisted as the dominant paradigm and focus of management recommendations for riparian forest conservation. Consequently, managers may overlook important effects of the surrounding landscape matrix. We determined if characteristics of the landscape matrix, particularly the amount of urban development surrounding a forest, were better predictors of bird communities than forest width. We sampled breeding-bird communities 3 times each June 2001–2004 in 33 riparian forest sites (69–565 m wide) in Ohio, USA. We examined if bird community structure and composition were more closely associated with forest width or the amount of urban development within 1 km of each forest using canonical correlation analysis. Results indicate that the landscape matrix surrounding these relatively large forest tracts explained >94% of the variation in bird communities compared to <6% explained by forest width. Numbers of Neotropical migrants were negatively associated with urbanization in the landscapes ( r = −0.43), whereas residents ( r = 0.57) and short-distance migrants ( r = 0.41) were positively associated with urbanization. Similar patterns persisted at the individual species level, particularly for Neotropical migrants as 76% of species in this guild were negatively related to urban development. Our findings suggest that the traditional approach to conserving riparian forests is not sufficient and that explicit consideration of the surrounding landscape matrix also should be a key component in conservation efforts.

Riparian forests, a unique but endangered ecosystem in Benin

Riparian forests are often small in area, but are of extreme ecological and economic value for local people. The interest of riparian forests lies in their resources: basically fertile and moist soils, water, wood and non-timber forest products that are utilised by neighbouring populations to satisfy their basic needs and as source of income. Their abusive overuse is widespread and growing in Benin. As a result rich biological resources, especially plant species, are disappearing before they can be inventoried and assessed. Most recent management plans for protected areas barely consider the conservation of riparian forests. The forest law in Benin recognises their uniqueness, but several problems arise in the implementation of the rules in these particular areas. The most common and widespread tree species in riparian forests in Benin are Pterocarpus santalinoides, Cola laurifolia, Syzygium guineense, Berlinia grandiflora, Elaeis guineensis, Manilkara multinervis, Xylopia parviflora, Dialium guineense, Diospyros mespiliformis and Parinari congensis. Waterways and their forested banks are rich in birdlife, and serve as a focal point for primates and animals of many kinds. Site-specific studies at ground level are essential to assess riparian systems because their narrow linear shapes generally require data on plant community structure, floristic composition and animal presence. Details of vegetation layers under the dominant trees cannot yet be detected by remotely sensed data. This paper presents an overview of the biological diversity of riparian forests in Benin and discusses several issues associated with their protection and conservation.