Biodiversity In Human-dominated Landscapes Research Articles

Increasing stability of a native freshwater fish assemblage following flow rehabilitation.

Stream restorations are increasingly critical for managing and recovering freshwater biodiversity in human-dominated landscapes. However, few studies have quantified how rehabilitative actions promulgate through aquatic communities over decades. Here, a long-term dataset is analyzed for fish assemblage change, incorporating data pre- and post-restoration periods, and testing the extent to which native assemblage stability has increased over time. In the late 1950s, a large capacity dam was installed on Putah Creek (Solano County, CA, USA), which altered the natural flow regime, channel structure, geomorphic processes, and overall ecological function. Notably, downstream flows were reduced (especially during summer months) resulting in an aquatic assemblage dominated by warm-water nonnative species, while endemic native species subsisted at low levels as subordinates. A court-mediated Accord was ratified in 2000, providing a more natural flow regime, specifically for native and anadromous fishes in the stream. The richness of nonnative species decreased at every site following the Accord, while the richness of native species increased or stayed constant. At the three most upstream sites, native species richness increased over time and ultimately exceeded nonnative richness. Native assemblage recovery was strongest upriver, closer to flow releases and habitat restoration activities, and decreased longitudinally downstream. Rank-abundance curves through time revealed that, while species evenness was low throughout the study, dominance shifted from nonnative to native species in the upstream sites coincident with rehabilitation efforts. Mean rank shifts decreased following flow rehabilitation; thus the assemblage became increasingly stable over time following flow rehabilitation. Putah Creek's rehabilitation may represent a model for others interested in improving endemic freshwater communities in degraded ecosystems.

Conservation-relevant plant species indicate arthropod richness across trophic levels: Habitat quality is more important than habitat amount

The massive declines in terrestrial arthropods reported across Europe call for effective methods to monitor and promote biodiversity in human-dominated landscapes. Previous studies vary in their support for the suitability of plants as indicators of arthropod diversity, while the potential of subsets of conservation-relevant plant species to estimate arthropod richness remains to be tested. Moreover, the relative importance of plant species richness compared to other factors driving arthropod richness, such as land-use intensity, habitat amount and landscape configuration, is poorly understood. We conducted a multi-scale field study in Southern Germany, sampling vascular plants and terrestrial arthropods in four local land-use types (forest, grassland, arable field, settlement) across large-scale gradients of climate and land-use intensity. We obtained an extensive arthropod dataset using Malaise traps as sampling method and DNA metabarcoding for species identification. We compared the correlation of three sets of plant species richness (total, red-listed and biotope-indicator plants) with arthropod richness, including different trophic and taxonomic groups. Using mixed-effect models, we assessed the partial effects of plant species richness, habitat amount and landscape configuration on local arthropod richness while controlling for climate and land-use effects, and explored the environmental drivers of plant species richness. Arthropod species numbers of all trophic groups strongly responded to species numbers of plants that indicate protected habitats, while red-listed plant species richness was a key determinant for the richness of red-listed arthropods and butterflies. In most cases, plant species richness and temperature were stronger drivers of arthropod richness than the amount of surrounding semi-natural habitat and landscape configuration. While total plant species richness was highest in settlements, the richness of biotope-indicator plants was highest in forests and positively influenced by the amount of semi-natural habitat and edge density. The number of red-listed plant species increased with edge density at the landscape scale but was independent of habitat amount. We conclude that the richness of conservation-relevant plant species provides a powerful indicator of arthropod diversity, and underpins the potential of such plant lists for monitoring habitat quality. Our study highlights the importance of openings in forests for conservation of plants and arthropods as well as of preserving and restoring fragments of high-quality biotopes in agricultural and urban areas where the amount of semi-natural habitat is limited.

A Step Towards Conserving Biodiversity in Human-Dominated Landscapes: Habitat Evaluation for Red Fox (Vulpes vulpes) in North-Western Pakistan

A Step Towards Conserving Biodiversity in Human-Dominated Landscapes: Habitat Evaluation for Red Fox (Vulpes vulpes) in North-Western Pakistan

Grassland type and presence of management shape butterfly functional diversity in agricultural and forested landscapes

Alteration of agricultural land use has led to a widespread loss of biodiversity in human-dominated landscapes. Degradation and gradual disappearance of natural and semi-natural habitats has become a global conservation problem. Together, intensive agriculture and the abandonment of extensively farmed areas endanger the wildlife of European landscapes. Our study aims to explore the complex processes that affect butterfly functional diversity and functional community composition in low-productive and threatened grasslands. We examined the functional characteristics of butterfly communities in response to three factors: habitat type (calcareous grassland vs. orchard meadow), management (managed vs. abandoned), and landscape context (forested vs. agricultural landscape). We surveyed butterflies of 20 calcareous grasslands and 20 orchard meadows in Central Germany. Both habitats are characterised by high structural diversity and extensive cultivation. To test the effects of our investigated variables, we selected six functional traits (overwintering, voltinism, wing length, diet, flight period, territoriality) for each butterfly species, and assigned values to them based on the literature. For our statistical analyses, we used single trait and multi-trait approaches. Our results showed that habitat type had the strongest filtering effect on butterfly functional traits of the three design variables. Functional diversity indices, such as functional richness and divergence values, were higher in calcareous grasslands than in orchard meadows. We found that calcareous grasslands are characterised by butterflies having more specialist traits (e.g., fewer food plants, fewer generations), which are favoured by grassland management and the vicinity of forests. Therefore, to maintain the threatened butterfly fauna of calcareous grasslands, extensive management should focus on these grasslands in forested landscapes. • Extensive management maintains higher butterfly diversity. • Both orchard meadows and calcareous grasslands harbour a valuable butterfly fauna. • Habitat type had the strongest filtering effect on butterfly functional traits. • Orchard meadows are characterised by butterflies with more generalist traits. • Calcareous grasslands are characterised by butterflies with more specialist traits.

Multiscale effects of habitat and surrounding matrices on waterbird diversity in the Yangtze River Floodplain

ContextWith the expansion in urbanization, understanding how biodiversity responds to the altered landscape becomes a major concern. Most studies focus on habitat effects on biodiversity, yet much less attention has been paid to surrounding landscape matrices and their joint effects.ObjectiveWe investigated how habitat and landscape matrices affect waterbird diversity across scales in the Yangtze River Floodplain, a typical area with high biodiversity and severe human-wildlife conflict.MethodsThe compositional and structural features of the landscape were calculated at fine and coarse scales. The ordinary least squares regression model was adopted, following a test showing no significant spatial autocorrelation in the spatial lag and spatial error models, to estimate the relationship between landscape metrics and waterbird diversity.ResultsWell-connected grassland and shrub surrounded by isolated and regular-shaped developed area maintained higher waterbird diversity at fine scales. Regular-shaped developed area and cropland, irregular-shaped forest, and aggregated distribution of wetland and shrub positively affected waterbird diversity at coarse scales.ConclusionsHabitat and landscape matrices jointly affected waterbird diversity. Regular-shaped developed area facilitated higher waterbird diversity and showed the most pronounced effect at coarse scales. The conservation efforts should not only focus on habitat quality and capacity, but also habitat connectivity and complexity when formulating development plans. We suggest planners minimize the expansion of the developed area into critical habitats and leave buffers to maintain habitat connectivity and shape complexity to reduce the disturbance to birds. Our findings provide important insights and practical measures to protect biodiversity in human-dominated landscapes.

Assessing restoration priorities for high-risk ecosystems: An application of the IUCN Red List of Ecosystems

Land clearing and ecosystem degradation are primary causes of loss of biodiversity and ecosystem services worldwide, putting at risk sustainable options for Earth and humankind. According to recent global estimates, degraded lands already account for at least 1 and up to 6 billion ha. Given high rates of habitat degradation and loss of biodiversity in human-dominated landscapes with high levels of ecosystem transformation, conventional approaches to conservation such as setting aside lands in protected areas, are not enough; in combination with ecosystem protection, ecological restoration is essential to ensure the conservation of biodiversity and delivery of ecosystem services. Despite recognition of the role of ecological restoration, the planning of restoration at the landscape scale remains a major challenge. Specifically, more studies are needed on developing restoration plans that maximize conservation and provisioning of ecosystem services, while minimizing competition with high-productivity land uses. We use Colombia, one of the world’s mega-diversity countries in which ca. 25 % of ecosystems are listed as critically endangered (CR), as a test case for exploring the potential advantages of including the Red List of Ecosystems, a newly developed tool for assessing conservation value, in restoration planning. We identified restoration priorities focused on both high-risk ecosystems and low-productivity lands, to maximize conservation value and minimize land-use conflicts. This approach allowed us to identify over 6 M ha of priority areas for restoration, targeting the restoration of 31 (75 %) of the country’s endangered ecosystems. Eight of the Regional Administrative Environmental Planning Areas (CARs) had greater than 20 % of their area identified as restoration priorities. We roughly estimated that the cost of restoring the prioritized areas with restoration through natural regeneration, using payment for ecosystem services (PES), would equal less than 50 % of the annual budget of the CARs. Our results are in sharp contrast (only 12 % agreement) with the priorities identified under the current National Restoration Strategy of Colombia, and highlight the potential contribution of the Red List of Ecosystems in refining and improving restoration planning strategies at both national and sub-national levels.

Effects of Forest Fragment Area on Interactions Between Plants and Their Natural Enemies: Consequences for Plant Diversity at Multiple Spatial Scales

Density-dependent interactions between plants and their natural enemies, including fungal pathogens and insect herbivores, help maintain plant species coexistence and diversity at local scales (α-diversity). However, turnover in plant species composition across space also contributes to biodiversity at larger spatial scales (β-diversity). Despite mounting evidence that enemies can maintain α-diversity, we know little about their contributions to β-diversity. Additionally, in the light of widespread habitat fragmentation and potentially modified insect and pathogen communities in forest fragments, the effects of fragment area on their diversity-maintaining roles are largely unknown. We carried out a field experiment to investigate how natural enemies in impact tree α and β-diversity in a fragmented rainforest landscape in the Western Ghats, India. In twenty-one rainforest fragments, we suppressed insects and fungi/oomycetes with pesticides, and examined changes in the diversity of tree seedlings. We found that fungicide had no effect on α-diversity, but significantly decreased β-diversity (species turnover among plots). The facilitative effects of fungi and oomycetes on β-diversity, however, weakened as fragments decreased in area, indicating that certain specialized plant-pathogen interactions may be lost when fragments become smaller. Insecticide, in contrast, increased α-diversity. However, insects tended to increase β-diversity between distant plots. In summary, we found that interactions between plants and their natural enemies help maintain β-diversity in large forest fragments but not in small fragments. Small fragments are often viewed as future reservoirs of biodiversity in human-dominated landscapes, but our findings suggest that modified interactions with natural enemies may result in the erosion of this diversity over time.

Effects of Landscape Changes on Species Viability: A Case Study from Northern Slovakia

Urbanization, increasing road networks, agricultural intensification, and land abandonment are widespread land change processes found in most European landscapes. As land changes affect animal species and their populations, there is a need to evaluate the effects of future developments on the viability of protected species. In this paper, we model population size and viability of selected indicator species for a selected area in Slovakia. Our results indicate that selected species are viable in the current landscape composition. However, the expected spread of settlement and the increase of road density in this area would likely lead to decline and loss of viability of species. Similarly, continuous land abandonment followed with spontaneous reforestation would likely trigger a decline of grassland species. In contrast, developing a biocorridor and restoration of existing green elements as modeled in our conservation scenario would strongly improve the viability of all species and avoid the impact of the expected developments. Our results underline the actions that prevent further loss of biodiversity in human-dominated landscapes and, thus, have particular importance for landscape planning and decision-making processes.

The Effect of the Surrounding Landscape and Socioeconomic characteristics on Woody Species Diversity in Homegardens of Shewarobit District, Northeast Ethiopia

Although homegardens are most often suggested as the refuges for biodiversity in human-dominated landscapes, how the surrounding landscape and socioeconomic characteristics affect this diversity in the tropics has received little research attention. Hence, this study has examined how these factors affect woody species diversity in homegardens of northeast Ethiopia. Three landscapes which are similar in agroecology were selected and in total 54 households were used for both a survey and a woody species inventory in respondents’ homegardens. The homegardens were stratified based on their locations in relation to crop fields and natural vegetation using satellite images from Google Earth. The variation in Shannon–Wiener diversity index among homegardens and the effect of the socioeconomic factors including household wealth status, homegarden area and the households’ types of uses of woody plants on species diversity were analyzed using one-way ANOVA. Altogether 53 woody plant species belonging to 35 botanical families were identified. Survey results indicated that the woody species diversity was higher in homegardens situated close to crop land as compared with the diversity in homegardens close to natural vegetation. Higher woody species diversity was recorded in homegardens which are larger in area and where the households’ types of uses of woody plants is higher. Moreover, the woody species diversity was found to be higher in homegardens of the high and medium income households when compared with that of poor households. Overall, results suggest that the concurrent ecological and socioeconomic studies are needed to design conservation strategy and policy for plant biodiversity in agricultural landscapes.

Nest predators, but not nest survival, differ between adjacent urban habitats

Growing human populations make it imperative for ecologists to identify strategies to conserve biodiversity in human-dominated landscapes, such as cities. Effects of urbanization on birds are particularly well-studied, but questions remain regarding the best conservation approaches. Debate about the relative utility of focusing conservation efforts on nature reserves versus developed lands has focused largely on comparing species abundance or presence, with few studies addressing underlying behavioral or demographic mechanisms. Here we evaluated differences in avian reproductive success in nature reserves and matrix habitats to test the assumption that nest predation is lower within areas protected from development. Specifically, we investigated 1) whether nest survival differed in replicated pairs of forest parks and residential neighborhoods and 2) whether differences in nest survival were associated with changes in which species most frequently depredated nests. From April–August 2007–2014, we monitored nests of two native birds, American robin (Turdus migratorius) and northern cardinal (Cardinalis cardinalis), and video-documented nest predators in paired forest-matrix habitats in the Columbus, Ohio metropolitan area. We found similar rates of nest survival in the two habitats for both robins (Χ21 = 0.715, p = 0.398, n = 741 nests) and cardinals (Χ21 = 0.926, p = 0.336, n = 1156 nests), but interactions between predators and prey differed. In particular, domestic cats (Felis catus) were over five times as likely to depredate cardinal nests in matrix habitats versus forest parks (Χ21 = 7.24, simulated p = 0.010; nforest = 3, nmatrix = 7). Our results suggest that at least in some circumstances, nest success of native birds may be equivalent between nature reserves and adjacent residential matrix habitats, and thus residential neighborhoods may contribute positively to bird conservation in urban landscapes.

Freshwater biodiversity in human-dominated landscapes: introduction

Freshwater biodiversity in human-dominated landscapes: introduction

Can contrast between forest and adjacent open habitat explain the edge effects on plant diversity?

Forest edges are key features in human-dominated landscape. Located between forest and non-forest habitats, edges induce biotic and abiotic changes, which may have profound consequences on vegetation diversity. Recent studies suggest the importance of different edge types in the modulation of edge-related responses. However, edge effect on the spatial dynamic of vegetation, from forest to non-forest habitats, remains unclear. Our aim was to compare the species richness and diversity of vegetation communities between forest and open habitats with their respective edges, in high-contrast versus low-contrast situations. The degree of contrast was defined according to the disturbance regimen of non-forest habitats. We surveyed vascular vegetation along transects in forest and open habitats and in their respective edges, in three regions of France. We showed that edge effects occur on plant diversity, whatever the region, but asymmetrically. Edge effect tends to be greater on the open side than on the forest side of the border. Species richness and diversity were generally higher in open edge than in open habitat, whereas no significant difference was observed between forest edge and forest habitat, whatever the contrast situation encountered. This study shows that the edge effects detected along a forest–edge–exterior habitat gradient may depend in large part on the disturbance regimen in open habitats as well as the vegetation pool size. We highlighted the need to carefully consider the edge types, e.g. their contrast with adjoining non-forest habitat, in further studies to identify the relevant factors and mechanisms behind edge-related response patterns of biodiversity in human-dominated landscapes.

Agroforestry for conserving and enhancing biodiversity

The intricate relationship between biodiversity loss and human well-being is increasingly being understood in ecological and economic terms. Despite the knowledge of the multiple dimensions of this relationship and its importance, species and ecosystems are still disappearing at an alarming rate. Anthropogenic pressures are the prime reason for this trend, yet attempts to reduce such pressures and conserve species in protected areas have only achieved limited success. This has led to the realization that sustainable consumptive use approaches that can combine production and conservation functions are also important in conserving biodiversity in human-dominated landscapes. Agroforestry, as part of a multifunctional working landscape, can play a major role in conserving and even enhancing biodiversity from farms to the landscape level in both tropical and temperate regions of the world. This special issue is an attempt to bring together a collection of articles that not only explore and demonstrate the biodiversity benefits of agroforestry, but also the mechanisms by which agroforestry systems sustain such high floristic and faunal diversity. While it is important to conserve biodiversity in protected areas, the articles in the special issue reiterate the importance of agroforestry as a critical tool in conserving biodiversity in human-dominated landscapes.

Modelling the effect of intersections in linear habitat on spatial distribution and local population density

Many species in human-dominated landscapes find their habitat in linear elements, such as road verges, hedgerows and ditches. Local concentrations of species have been observed in the intersections of linear elements, but their spatial distribution and local population density in this linear habitat are not well captured by existing theory. Using a simple, spatially explicit individual-based GIS-model simulating hedgerow bird species with different movement abilities, local high population density of our model species in intersections and their reduced density or absence in linear habitat could be explained by limited movement. We hypothesise that, for species with low movement ability, intersections of linearly shaped habitat could contain several local populations. We argue that these predictions are valid for organisms occurring in linear habitat with limited movement relative to the dimensions of their habitat, and whose movement is directed by their habitat. Our findings support the importance of intersections for biodiversity in human-dominated landscapes, as they may serve as refuges from which individuals can (re-)colonise unoccupied habitat.

Functional landscape heterogeneity and animal biodiversity in agricultural landscapes

Biodiversity in agricultural landscapes can be increased with conversion of some production lands into 'more-natural'- unmanaged or extensively managed - lands. However, it remains unknown to what extent biodiversity can be enhanced by altering landscape pattern without reducing agricultural production. We propose a framework for this problem, considering separately compositional heterogeneity (the number and proportions of different cover types) and configurational heterogeneity (the spatial arrangement of cover types). Cover type classification and mapping is based on species requirements, such as feeding and nesting, resulting in measures of 'functional landscape heterogeneity'. We then identify three important questions: does biodiversity increase with (1) increasing heterogeneity of the more-natural areas, (2) increasing compositional heterogeneity of production cover types and (3) increasing configurational heterogeneity of production cover types? We discuss approaches for addressing these questions. Such studies should have high priority because biodiversity protection globally depends increasingly on maintaining biodiversity in human-dominated landscapes.

The contribution of motorway stormwater retention ponds to the biodiversity of aquatic macroinvertebrates

Biodiversity conservation does predominantly focus on protected natural areas, but has to consider also the usually Human-dominated matrix in which these natural areas are embedded. Here we study highway stormwater retention ponds, which may act as refuges for native flora and fauna and contribute to the maintenance of biodiversity in Human-dominated landscapes. However, the biodiversity supported by such artificial ponds has received little attention so far. Using standardised methods, we addressed the potential role of highway stormwater ponds as refuges by comparing aquatic macroinvertebrate communities (Coleoptera, Heteroptera, Odonata and Gastropoda) in highway stormwater ponds with ponds in the wider landscape. As expected from their pollutant retention function, highway ponds differed in abiotic conditions from surrounding ponds. However, they supported aquatic macroinvertebrate communities at least as rich and diverse at the family level as surrounding ponds and exhibited similar variability in family community composition and structure. The main difference we observed was a higher abundance of small and/or short-lived invertebrates in the highway ponds. These similar community compositions and structures suggest that highway ponds contribute to the biodiversity of the pond network at a regional scale. Thus, road practitioners should consider highway ponds not only for their hydrological and pollutant retaining purposes but also as a possibility to increase the role of highway verges as a refuge and, consequently, landscape connectivity. The management of these water bodies should recognise their potential for biodiversity especially in Human-dominated landscapes.

Scott, Goble, and Davis — The Endangered Species Act at thirty. Conserving Biodiversity in Human-dominated Landscapes. Volume 2 The Endangered Species Act at thirty. Conserving Biodiversity in Human-dominated Landscapes. Volume 2. Scott J. Michael Dale D. Goble Frank W. Davis editors. 2006 Washington, D.C Island Press xiii + 360 p. $85.00 (cloth) ISBN: 1-59726-054-1 (alk. paper); $35.00 (paper), ISBN: 1-59726-055-X

Scott, Goble, and Davis — The Endangered Species Act at thirty. Conserving Biodiversity in Human-dominated Landscapes. Volume 2 The Endangered Species Act at thirty. Conserving Biodiversity in Human-dominated Landscapes. Volume 2. Scott J. Michael Dale D. Goble Frank W. Davis editors. 2006 Washington, D.C Island Press xiii + 360 p. $85.00 (cloth) ISBN: 1-59726-054-1 (alk. paper); $35.00 (paper), ISBN: 1-59726-055-X