Fragmentation Of Natural Habitats Research Articles

Population connectivity of aquatic insects in a dam‐regulated, desert river

AbstractHumans have exaggerated natural habitat fragmentation, negatively impacting species dispersal and reducing population connectivity. Habitat fragmentation can be especially detrimental in freshwater populations, whose dispersal is already constrained by the river network structure. Aquatic insects, for instance, are generally limited to two primary modes of dispersal: downstream drift in the aquatic juvenile life stages and flight during the terrestrial winged adult stage. Yet the impacts of large hydropower dams can make rivers uninhabitable for incoming (drifting) juvenile insects, with remaining refugia found only in tributaries. The ability of adult aquatic insects to traverse such river stretches in search of suitable tributary habitat likely depends on factors such as species‐specific dispersal ability and distance between tributaries. To explore the intersection of natural and human‐induced habitat fragmentation on aquatic insect dispersal ability, we quantified population genetics of three taxa with varying dispersal abilities, a caddisfly (Hydropsychidae, Hydropsyche oslari), a mayfly (Baetidae: Fallceon quilleri), and a water strider (Veliidae: Rhagovelia distincta), throughout tributaries of the Colorado River in the Grand Canyon, Arizona, USA. Using 2bRAD reduced genome sequencing and landscape genetics analyses, we revealed a strong pattern of isolation by distance among mayfly populations. This contrasts with caddisfly and water strider populations, which were largely panmictic. Analysis of thousands of informative single nucleotide polymorphisms showed that realized dispersal ability may not be accurately predicted by species traits for these widespread species. Principal components analysis revealed a strong division between caddisfly populations upstream and downstream of Havasu Creek (279 km through the 390 km study reach), suggesting that the geography of the Grand Canyon imposes a dispersal barrier for this species. Our use of genetic tools in the Grand Canyon to understand population structure has enabled us to elucidate dispersal barriers for aquatic insects. Ultimately, these data may be useful in informing effective conservation management plans for understudied organisms of conservation interest.

The impact of globalization and climate change on Trichinella spp. epidemiology

The main reservoir hosts of nematodes of the genus Trichinella are wild carnivores, although most human infections are caused by the consumption of pork. This group of zoonotic parasites completes the entire natural life cycle within the host organism. However, there is an important phase of the cycle that has only been highlighted in recent years and which concerns the permanence of the infecting larvae in the striated muscles of the host carcasses waiting to be ingested by a new host. To survive in this unique biological niche, Trichinella spp. larvae have developed an anaerobic metabolism for their survival in rotting carcasses and, for some species, a resistance to freezing for months or years in cold regions. Climate changes with increasingly temperatures and reduction of environmental humidity lower the survival time of larvae in host carcasses. In addition, environmental changes affect the biology and ecology of the main host species, reducing their number and age composition due to natural habitat fragmentation caused by increasing human settlements, extensive monocultures, increasing number of food animals, and reduction of trophic chains and biodiversity. All of these factors lead to a reduction in biological and environmental complexity that is the key to the natural host-parasite balance. In conclusion, Trichinella nematodes can be considered as an indicator of a health natural ecosystem.

Natural habitat cover and fragmentation per se influence orchid-bee species richness in agricultural landscapes in the Brazilian Cerrado

Natural habitat cover and fragmentation per se influence orchid-bee species richness in agricultural landscapes in the Brazilian Cerrado

Fragmentation of natural habitats by urban development at Sochi

ABSTRACT The fragmentation of natural habitats in Krasnodar Krai is analysed by reconstructing the spatial pattern of habitat quality. Habitat fragmentation effects were explored at the fragment level, with 260 fragments as units of study and a computed habitat degradation degree index computed using ArcGIS software and variance analysis. There is a direct connection between the level of habitat degradation and fragment size, so a habitat fragment of more than 50 ha suffered a low level of habitat degradation but those of less than 1.5 ha exhibited severe degradation.

Diversity of Butterflies Aroundpanje - Funde Wetland, Uran, Navi Mumbai West Coast of India

Uran is under heavy process of Urbanization, Industrialization, land filling, reclamation cutting of mangroves, shipping and port related activities resulting in fragmentation of natural habitats. Butterflies are bio-indicators of habitat quality and are sensitive to any changes taking place in habitat a survey of butterfly diversity of Panje –Funde wetland and nearby area was conducted for a period of one year from June 2017 to May 2018. During present investigation total of 66 species of butterflies belonging to 46 genera and 6 families were recorded. Butterflies from family Nymphalidae showed maximum species diversity dominance with 17 genera and 27 species followed by Lycaenidae with 10 genera and 10 species, Pieridae with 9 genera and 15 species Hesperiidae with 6 genera and 6 species, Papilionidae represented with 3 genera and 6 species, the least number of 1 genus and 2 species were recorded from the family Riodinidae. There is urgent need for effective habitat and biodiversity conservation program in this Eco sensitive area.

Synergistic effects of climate and landscape change on the conservation of Amazonian lizards.

The leading causes of the worldwide decline in biodiversity are global warming, allied with natural habitat loss and fragmentation. Here, we propose an analysis of the synergistic effects of these two factors in 63 species of Amazonian lizards. We predicted that the high-climatic suitability areas of species would be significantly impacted by different deforestation scenarios and the resultant landscape structure and considered that forest-dwelling species would be especially susceptible to deforestation scenarios. We also pointed out species threatened by both drivers and suggested critical areas for their future conservation. According to our results, most species will face future reductions in suitable areas for their occurrence according to five different patterns, two of which represent significant risks for 15 species. Some of these species already deal with severe habitat loss and fragmentation of their current distribution ranges, whereas others will suffer a considerable area reduction related to future range shifts. We emphasize the importance of protected areas (PAs), especially indigenous lands, and the need to plan combined strategies involving PAs’ maintenance and possible implementation of ecological corridors. Finally, we highlight eight species of thermoconformer lizards that constitute present and future conservation concerns related to the combined effects of climate change and habitat loss and that should be carefully evaluated in extinction risk assessments.

Global impacts of future urban expansion on terrestrial vertebrate diversity

Rapid urban expansion has profound impacts on global biodiversity through habitat conversion, degradation, fragmentation, and species extinction. However, how future urban expansion will affect global biodiversity needs to be better understood. We contribute to filling this knowledge gap by combining spatially explicit projections of urban expansion under shared socioeconomic pathways (SSPs) with datasets on habitat and terrestrial biodiversity (amphibians, mammals, and birds). Overall, future urban expansion will lead to 11–33 million hectares of natural habitat loss by 2100 under the SSP scenarios and will disproportionately cause large natural habitat fragmentation. The urban expansion within the current key biodiversity priority areas is projected to be higher (e.g., 37–44% higher in the WWF’s Global 200) than the global average. Moreover, the urban land conversion will reduce local within-site species richness by 34% and species abundance by 52% per 1 km grid cell, and 7–9 species may be lost per 10 km cell. Our study suggests an urgent need to develop a sustainable urban development pathway to balance urban expansion and biodiversity conservation.

Diet Composition of Bats in a Human-Modified Tropical Landscape

Human-modified landscapes are often composed of small and isolated natural habitat fragments immersed in agricultural and urban matrices. Within them, ecosystem services provided by wildlife, such as pest insect suppression, may decrease or even be lost leading to a substantial increase in agricultural production costs. Pest insect suppression by bats has been identified as an essential ecosystem service but remains poorly investigated. For example, we still lack a basic understanding of the proportion of pest insects that comprises the diet of many bat species. Here, we explored the diet composition of eight Brazilian bat species (78 individuals) in a human-modified landscape through the analysis of stable carbon (13C) and nitrogen (15N) isotopes. Bats were categorised into guilds: open-space aerial insectivores, narrow-space gleaning frugivores, or narrow-space gleaning nectarivores. We divided the insects collected into three groups depending on their δ13C values: forest, mixed, and pest insects. We found that open-space insectivorous bats had the highest proportion of insects in total in their diet — consuming primarily from the forest group (56%) and the pest group (34%). Interestingly, narrow-space gleaning frugivores also consumed pest insects (almost 20%). The narrow-space gleaning nectarivores had traces of insects in their diet, yet the actual proportion was inconclusive. Even though bats were from different guilds, with diets consisting mainly of plants and insects, the δ15N indicated that they fitted to similar trophic levels, as secondary consumers. Therefore, the trophic level of nectarivorous and frugivorous bats showed a more generalist diet than previously assumed. The proportion of forest insects in the diet of open-space aerial insectivores may indicate the importance of small forest patches as food resources for wildlife such as the ones included in human-modified landscapes. The bats' contribution to this ecosystem service could improve the economic conservation value of Neotropical bats in human-modified landscapes.

Both landscape and local factors influence plant and hexapod communities of industrial water-abstraction sites.

At the landscape level, intensification of agriculture, fragmentation, and destruction of natural habitats are major causes of biodiversity loss that can be mitigated at small spatial scales. However, the complex relationships between human activities, landscapes, and biodiversity are poorly known. Yet, this knowledge could help private stakeholders managing seminatural areas to play a positive role in biodiversity conservation.We investigated how water‐abstraction sites could sustain species diversity in vascular‐plant communities and two taxonomic groups of insect communities in a fragmented agricultural landscape.Landscape‐scale variables (connectivity indices and surrounding levels of herbicide use), as well as site‐specific variables (soil type for vascular plants, floral availability for Rhopalocera, and low herbaceous cover for Orthoptera), were correlated to structural and functional metrics of species community diversity for these taxonomic groups, measured on 35 industrial sites in the Ile‐de‐France region in 2018–2019. Rhopalocera and Orthoptera consisted essentially of species with a high degree of dispersal and low specialization, able to reach the habitat patches of the fragmented landscape of the study area. Sandy soil harbored more diverse vascular‐plant communities. Plant diversity was correlated to a greater abundance of Rhopalocera and a lower richness of Orthoptera.Increasing landscape connectivity was related to higher abundance of plants and Rhopalocera, and a higher evenness index for Orthoptera communities. Higher levels of herbicide use were related to a decrease in the biodiversity of plants and Rhopalocera abundance. High levels of herbicide favored high‐dispersal generalist plants, while high levels of connectivity favored low‐dispersal plants. Specialist Orthoptera species were associated with low herbaceous cover and connectivity.Water‐abstraction sites are valuable seminatural habitats for biodiversity. Changing intensive agricultural practices in surrounding areas would better contribute to conserving and restoring biodiversity on these sites.

Genetic Diversity and Structure of Anax imperator Leach, 1815 Populations (Odonata: Aeshnidae) in Ponds at Regional and European Scales

Anthropogenic activities cause loss and fragmentation of natural habitats and have strong effects on population maintenance by increasing their isolation. Pond ecosystems are scattered waterbodies that can interact as a network connected by dispersal events of freshwater organisms. Identifying local genetic differentiations and understanding how gene flow occurs across these networks is essential to prevent risks associated with environmental perturbations. This study aimed to investigate genetic diversity and structure of Anax imperator Leach, 1815 populations at both regional and European scales using seven microsatellites markers. Seven populations of A. imperator were sampled in northwestern France and four populations were sampled in Italy (Sicily), Czech Republic, Switzerland and United Kingdom (U.K.). French populations presented a low genetic differentiation indicating a high gene flow and confirming dispersal events of this species between ponds at regional scale. No pattern of isolation by distance was found at the European scale. The populations presented a low genetic differentiation and no pattern of isolation by distance, suggesting historical or current movements of individuals. Only the U.K. population presented a significant genetic differentiation from other European populations, suggesting that the English Channel might act as a barrier to gene flow for A. imperator. However, Bayesian analysis showed that some dispersal events could occur between the U.K. and France (Normandy), probably facilitated by prevailing winds.

Matrix quality and habitat type drive the diversity pattern of forest steppe fragments

The quality of the surrounding landscape matrix often determines the biodiversity pattern of the remaining natural habitat fragments. Dispersal of organisms depends mostly on species traits related to mobility and the contrast between the habitat fragment and the matrix. Therefore, variation in species composition among fragments, i.e. beta-diversity, can also be affected by matrix quality. In our study, we focused on structurally complex forest steppe fragments in Central Europe for revealing the effects of fragment size and matrix quality. We investigated 18 fragments along a gradient ranging in size from 0.2 to 6ha, and embedded in a gradient of changing matrix quality. We collected data on plants, spiders and ants in three different habitat types: natural forest and steppe parts of the forest steppe fragments and in the directly neighboring dominant element of the landscape matrix, being pine plantations. Species turnover (beta diversity) was higher for steppes than for forests indicating a higher degree of isolation for steppes. Increasing matrix quality decreased plant species richness in small fragments. The low dispersal between fragments prevents the displacement of poor competitors by stronger competitors and promotes the coexistence of species. Matrix quality positively affected spider richness independently of fragment size, but had no effect on ants. These differences among taxa highlight the complexity of the effects of landscape structure, and calls for a situation-specific optimization of landscape management in nature conservation. For our particular situation, the findings provide evidence that improving matrix quality would help preserving the threatened forest steppe biota.

Bee Representations in Human Art and Culture through the Ages

Abstract The field of bioaesthetics seeks to understand how modern humans may have first developed art appreciation and is informed by considering a broad range of fields including painting, sculpture, music and the built environment. In recent times there has been a diverse range of art and communication media representing bees, and such work is often linked to growing concerns about potential bee declines due to a variety of factors including natural habitat fragmentation, climate change, and pesticide use in agriculture. We take a broad view of human art representations of bees to ask if the current interest in artistic representations of bees is evidenced throughout history, and in different regions of the world prior to globalisation. We observe from the earliest records of human representations in cave art over 8,000 years old through to ancient Egyptian carvings of bees and hieroglyphics, that humans have had a long-term relationship with bees especially due to the benefits of honey, wax, and crop pollination. The relationship between humans and bees frequently links to religious and spiritual representations in different parts of the world from Australia to Europe, South America and Asia. Art mediums have frequently included the visual and musical, thus showing evidence of being deeply rooted in how different people around the world perceive and relate to bees in nature through creative practice. In modern times, artistic representations extend to installation arts, mixed-media, and the moving image. Through the examination of the diverse inclusion of bees in human culture and art, we show that there are links between the functional benefits of associating with bees, including sourcing sweet-tasting nutritious food that could have acted, we suggest, to condition positive responses in the brain, leading to the development of an aesthetic appreciation of work representing bees.

Long-Term Land Use and Landscape Pattern Changes in a Marshland of Hungary

This paper presents the trends of landscape change in the marshes on the southern shore of Lake Balaton, a wetland profoundly transformed by human activities. The study does not only deal with alterations in the areal proportions of land use classes but also quantitatively analyses landscape pattern, comparing landscape metrics on different dates. Based on the findings, proposals for rehabilitation are made. Through the restoration of wetland habitats, the provision level of ecosystem services can be raised. Landscape change was investigated from 1783 to 2020. For this purpose, archive maps were digitized, CORINE land cover datasets corrected by Sentinel-2 imagery were employed and from the vector data, the proportions of land use classes were calculated. For landscape pattern perimeter, area, neighbourhood and diversity metrics were used, calculated by ArcGIS vLATE plugin. It was pointed out that in land cover, the share of wetlands considerably declined over the centuries but in recent decades somewhat expanded. In the 20th century, grasslands were the predominant land use class, but with the spread of other categories, land use has become more complex. Landscape metrics show an increased fragmentation of natural habitats, a higher number of patches and edge density, leading to higher landscape diversity. Rehabilitation proposals include the establishment of rainwater retention reservoirs, the conversion of arable land which cannot be cultivated profitably to close-to-natural classes (first of all, grasslands) and the plantation of gallery forests of native tree species along canals. In comparison with other regions, similar temporal trends and spatial distributions are observed. For instance, the internationally well-known transformation of the Doñana wetland started later but was more intensive than in Hungary.

Review on Governance in Hydroelectric Projects and Impacts on Natural Resources

This article reviewed the literature to highlight how governance in hydroelectric enterprises is configured and the impacts on natural resources resulting from this type of energy production. The methodological procedures were based on the PRISMA recommendation (Main Items for Reporting Systematic Reviews and Meta-analysis) and indexed articles were used from the SCOPUS database. It was evidenced that more than 1/3 of the studies were conducted in Brazil, highlighting the potential of the Amazon region of the country for the construction of hydroelectric dams. Four essential subjects were identified as to be observed by the governance of these enterprises: stakeholder participation, habitat fragmentation, social impacts, and impacts on fish species. These subjects constitute three categories that synthesize governance in hydroelectric projects and the impacts on natural resources: energy policies – which generate benefits for the private sector and contemplate very little the local communities and the environment; water resources and fish - the impacts are related to the type of enterprise to be built, which can compromise the migration and reproduction of fish, in addition to the increasing concentration of nutrients in reservoirs and changes of the water quality; and biodiversity and ecosystem – which are affected by the fragmentation and alteration of natural habitats caused by dam floods.

Sixty years of land-use and land-cover change dynamics in a global biodiversity hotspot under threat from global change

ABSTRACT Constitución County in Chile shows one of the highest landscape transformations in the world due to the expansion of forest plantations. This work describes the land use/cover dynamics over a long period extending over 60 years in Constitución County. The results showed that 60% of the county extent was covered by natural vegetationt in 1955. However, forest plantation increased to 36% by 1975 and reached 72% by 2014. This expansion was mainly achieved by replacing native vegetation revealing evidence of the impact of forest plantations on native vegetation even before decree-law 701 (1974). Forest plantation expansion produced fragmentation and loss of natural habitat, and 50% of the remaining habitats showed low habitat quality by 2014. Finally, in 2017 a wildfire burned 77% and 42% of the remaining native forest and shrubland. These results showed the long-lasting impact of forest plantations, underpinning the need to move towards a new sustainable forest model.

Functional composition of ant assemblages in habitat islands is driven by habitat factors and landscape composition

Fragmented natural habitats within human-transformed landscapes play a key role in preserving biodiversity. Ants as keystone species are essential elements of terrestrial ecosystems; thus, it is important to understand the factors influencing their presence. In a large-scale multi-site study, we surveyed ant assemblages using sweep netting and D-vac sampling on 158 ancient burial mounds preserving grassland habitats in agricultural landscapes in East-Hungary. We asked the following questions: (1) How do habitat factors and landscape composition affect species richness and functional diversity of ants? (2) Which ant traits are affected by habitat factors and landscape composition? Despite their small sizes, mounds as permanent and relatively undisturbed landscape elements could provide safe havens for diverse ant assemblages even in transformed agricultural landscapes. The complex habitat structure of wooded mounds supported high species and functional diversity of ant assemblages. Ant species on wooded mounds had small or medium-sized colonies, enabling the co-existence of more species. The effect of landscape composition on ant assemblages was mediated by habitat factors: steep slopes buffered the negative effect of the cropland matrix and enabled higher ant diversity.

Genetic Diversity and Population Structure Revealed by SSR Markers on Endemic Species Osmanthusserrulatus Rehder from Southwestern Sichuan Basin, China

Osmanthus serrulatus Rehder (Oleaceae) is an endemic spring-flowering species in China. It is narrowly distributed in the southwestern Sichuan Basin, and is facing the unprecedented threat of extinction due to problems associated with natural regeneration, habitat fragmentation and persistent and serious human interference. Here, the genetic diversity and population structure of 262 individuals from ten natural populations were analyzed using 18 microsatellites (SSR) markers. In total, 465 alleles were detected across 262 individuals, with a high polymorphic information content (PIC = 0.893). A high level of genetic diversity was inferred from the genetic diversity parameters (He = 0.694, I = 1.492 and PPL = 98.33%). AMOVA showed that a 21.55% genetic variation existed among populations and the mean pairwise Fst (0.215) indicated moderate genetic population differentiation. The ten populations were basically divided into three groups, including two obviously independent groups. Our results indicate that multiple factors were responsible for the complicated genetic relationship and endangered status of O. serrulatus. The concentrated distribution seems to be the key factor causing endangerment, and poor regeneration, human-induced habitat loss and fragmentation seem to be the primary factors in the population decline and further genetic diversity loss. These findings will assist in future conservation management and the scientific breeding of O. serrulatus.

Landscape-scale forest loss shapes demographic structure of the threatened tropical palm Euterpe edulis mart. (Arecaceae)

The expansion of human activities has led to drastic changes in the original landscapes in which tropical forests stand, causing the loss and fragmentation of natural habitats. Both processes induce changes in forest structure and local microclimatic conditions that are important modulators of the survival and demographic structure of plant species. The Neotropical palm Euterpe edulis Mart. (Arecaceae) is a keystone species largely consumed by several animals. Nevertheless, such emblematic species has also been over-harvested for palm-heart extraction, which led it to be currently classified as vulnerable to extinction. Understanding the main predictors affecting its persistence in forest remnants is essential for proposing strategies to modify this current scenario. In this context, we aimed to investigate how processes occurring in two different spatial scales (i.e. forest cover at the landscape scale and local microclimatic conditions) affect the demographic structure of E. edulis. We selected 20 forest fragments along the Brazilian Atlantic Forest in southern Bahia, embedded within landscapes ranging from 10 to 98% of forest cover amount. In each fragment, a plot of 100 × 50 m was established and all individuals of E. edulis were counted. A datalogger was also deployed in the center of the fragment to collect data of air temperature and relative local humidity. We used a zero-altered negative binomial regression (ZANB) to investigate the influence of forest cover and microclimate variables on the demographic structure of E. edulis. A total of 6528 individuals distributed in the five ontogenetic stages was recorded, with Juveniles presenting the highest number of individuals. Forest cover, not microclimate, was the best predictor of the demographic structure for all ontogenetic stages. We suggest that deforested areas are also more prone to palm harvest, which might explain the pervasive effects on the species persistence. We strongly recommend the maintenance and restoration of forest areas to ensure the maintenance of current populations of this endangered palm species. Yet due to the species overexploitation, reintroducing the species to already depleted fragments is urgently required along the Atlantic coast, combined with an increase in surveillance and environmental education programs to curb illegal extraction in highly deforested areas.

Assessing the effectiveness of protected areas against habitat fragmentation and loss: A long-term multi-scalar analysis in a mediterranean region

Landscape fragmentation and human-induced land-cover changes are two of the main current threats to nature conservation. To face such challenges, the development of networks of Protected Areas (PAs) has become a central element of nature conservation policies. The main objective of this study is to evaluate the effectiveness of PAs against long-term natural habitat fragmentation and loss at a regional scale in a South West European context (Andalusia, Spain). A multiscalar approach –covering the entire region, the regional PAs network, the complete set of Andalusian Nature Parks and ten individual Parks– has been adopted for the analysis of four landscape metrics. The study covers a time span of approximately 50 years (1956–2007) divided into two periods (1956–1984 and 1984–2007), which allows for the assessment of the effects of PAs development in the region. The results show that habitat loss has a relatively low incidence and is distributed very irregularly throughout the region under study. In contrast, habitat fragmentation has a strong incidence at all scales of analysis. The loss of habitat continuity is mainly located in non-protected areas. Small losses of natural cover in key areas located outside PAs may lead to a strong increase in habitat fragmentation at the regional scale and indirectly affect valuable natural areas under protection. According to the results, it is highly advisable to reinforce the ecological connections between large PAs and adopt a more ecologically sound and proactive landscape planning approach in non-protected environments.

Is the southern patas monkey Erythrocebus baumstarki Africa's next primate extinction? Reassessing taxonomy, distribution, abundance, and conservation.

The "Critically Endangered" southern patas monkey Erythrocebus baumstarki, thought to be endemic to Tanzania, has been resurrected to species level based on its geographic isolation, and on the coloration and pattern of its pelage. This study presents the first evidence for E. baumstarki in Kenya and reviews its historic and current geographic distributions based on the literature, museum specimens, online platforms, responses to requests for site records, and our own fieldwork. The distribution of E. baumstarki in the early 20th century was roughly 66,000 km2 . This has declined about 85% to around 9700 km2 at present (post-2009). The current "Extent of Occurrence" is only about 2150 km2 . This species was extirpated from Kenya in about 2015 and from the Kilimanjaro Region in Tanzania in about 2011. At present, E. baumstarki appears to be restricted to the protected areas of the western Serengeti, with the western Serengeti National Park being the stronghold. The number of individuals remaining is probably between 100 and 200, including between 50 and 100 mature individuals. The ultimate threat to E. baumstarki is the very rapidly increasing human population, while the main proximate threats are the degradation, loss, and fragmentation of natural habitats, and the related competition with people and livestock for habitat and water, particularly during droughts. Other problems are hunting by poachers and domestic dogs, and probably loss of genetic variation and climate change. This article provides recommendations for reducing the threats and promoting the recovery of E. baumstarki. We hope this article heightens awareness of the dire conservation status of E. baumstarki and encourages an increase in research and conservation action for this monkey.