scholarly journals Impact of cost distance and habitat fragmentation on the daily path length of Rhinopithecus bieti

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9165
Author(s):  
Cong Li ◽  
Xumao Zhao ◽  
Dayong Li ◽  
Paul Alan Garber ◽  
Zuofu Xiang ◽  
...  
Keyword(s):  
Habitat Fragmentation ◽  
Path Length ◽  
Landscape Heterogeneity ◽  
Landscape Configuration ◽  
Ranging Behavior ◽  
Forest Patches ◽  
Daily Path Length ◽  
Statistical Tool ◽  
Rhinopithecus Bieti ◽  
Cost Distance

An understanding of primate movement patterns in response to natural and anthropogenically induced changes in habitat heterogeneity, food availability, and plant species distribution is essential for developing effective management and conservation programs. Therefore, from July 2013 to June 2014, we examined the effects of landscape configuration on the ranging behavior (daily path length, DPL) of the Endangered Yunnan snub-nosed monkey (Rhinopithecus bieti) in the Baimaxueshan National Nature Reserve (27°34′N, 99°17′E) in Gehuaqing, China. Given the extreme difficulties in following the study group across high altitude mountainous terrain across an elevation of 2,500–4,000 m, we were only able to collect DPL using 3-4 GPS points per day on 21 individual days. We found that R. bieti traveled the shortest DPL in winter (1,141.31 m), followed by spring (2,034.06 m) and autumn (2,131.19 m). The cost distance, a statistical tool designed to estimate the difficulty of a species moving across its distributional range, was lowest in autumn (205.47), followed by spring (225.93) and winter (432.59) (one-way ANOVA: F = 3.852, P = 0.026, df = 2). The habitat fragmentation index (HFI), which measures the density of forest patches, indicated areas visited in the winter were more fragmented (HFI = 2.16) compared to spring (HFI = 1.83) or autumn (HFI = 1.3). Although our results should be considered preliminary, they suggest that both the availability of suitable travel routes and habitat fragmentation, driven by high-intensity human disturbance, constrain the movement of R. bieti. We found that undisturbed areas of the bands’ range contained a high density of lichens, which represent a nutritious and abundant and year-round food source for Yunnan snub-nosed monkeys. In order to protect this Endangered species, we recommend that researchers construct detailed maps of landscape heterogeneity, particularly habitat connectivity, forest fragmentation, and seasonal variation in the location of major food patches in order to better understand and mitigate the effects of seasonal habitat change on patterns of R. bieti habitat utilization and population viability.

scholarly journals Landscape heterogeneity buffers biodiversity of simulated meta-food-webs under global change through rescue and drainage effects

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Remo Ryser ◽  
Myriam R. Hirt ◽  
Johanna Häussler ◽  
Dominique Gravel ◽  
Ulrich Brose
Keyword(s):  
Habitat Fragmentation ◽  
Food Web ◽  
Food Webs ◽  
Landscape Heterogeneity ◽  
Landscape Connectivity ◽  
Biodiversity Loss ◽  
Mechanistic Explanation ◽  
Population Densities ◽  
Rescue Effect ◽  
Drainage Effect

AbstractHabitat fragmentation and eutrophication have strong impacts on biodiversity. Metacommunity research demonstrated that reduction in landscape connectivity may cause biodiversity loss in fragmented landscapes. Food-web research addressed how eutrophication can cause local biodiversity declines. However, there is very limited understanding of their cumulative impacts as they could amplify or cancel each other. Our simulations of meta-food-webs show that dispersal and trophic processes interact through two complementary mechanisms. First, the ‘rescue effect’ maintains local biodiversity by rapid recolonization after a local crash in population densities. Second, the ‘drainage effect’ stabilizes biodiversity by preventing overshooting of population densities on eutrophic patches. In complex food webs on large spatial networks of habitat patches, these effects yield systematically higher biodiversity in heterogeneous than in homogeneous landscapes. Our meta-food-web approach reveals a strong interaction between habitat fragmentation and eutrophication and provides a mechanistic explanation of how landscape heterogeneity promotes biodiversity.

scholarly journals Determinants of Distribution of Large Mammals in Seti River Basin, Tanahun District of Western Nepal

2019 ◽  
Vol 24 (1) ◽  
pp. 63-71 ◽  
Author(s):  
Jagan Nath Adhikari ◽  
Bishnu Prasad Bhattarai ◽  
Tej Bahadur Thapa
Keyword(s):  
Habitat Fragmentation ◽  
River Basin ◽  
Vital Role ◽  
Scientific Management ◽  
Area Network ◽  
Large Mammals ◽  
Human Disturbances ◽  
Forest Patches ◽  
Alien Plant ◽  
Community Forests

Forest landscape in Seti River basin of Western Nepal is not conserved within the protected area network. Wildlife habitats in Seti River basin are more vulnerable due to high anthropogenic disturbance and habitat fragmentation. Present study mainly focused to evaluate the major factors that determine the distribution of large mammals in Seti River basin by walking through 34 line transects that covered a total of 59.89 km. The distribution of large mammals was greatly affected by habitat types, human disturbances, topography and altitude. Himalayan gorals were recorded in the steep grass covered areas where as Muntjacs were found in most of the habitats and slopes. There was low occurrence of all species nearer to the settlements and roads. Besides, water sources played a vital role in distribution of wildlife, as there were more occurrences of signs of large mammals nearby water resources. In the study area, community forests played a major role in the conservation of viable population of large mammals. However, habitat fragmentation due to scattered human settlements and degradation of foraging grounds such as grasslands by succession and invasion of alien plant species added more threats to the survival of large mammals. Therefore, such situation can be improved through the protection of connecting forest patches and scientific management of forests and grasslands.

scholarly journals Influence of landscape structure on Euglossini composition in open vegetation environments

2017 ◽  
Vol 17 (1) ◽  
Author(s):  
Eduardo Freitas Moreira ◽  
Rafaela Lorena da Silva Santos ◽  
Maxwell Souza Silveira ◽  
Danilo Boscolo ◽  
Edinaldo Luz das Neves ◽  
...  
Keyword(s):  
Species Richness ◽  
Landscape Structure ◽  
Multiple Scales ◽  
Landscape Heterogeneity ◽  
Species Abundance ◽  
Information Criterion ◽  
Landscape Configuration ◽  
Habitat Amount ◽  
Savanna Vegetation ◽  
Habitat Amount Hypothesis

Abstract The fauna of Euglossini bees is poorly known in savanna regions, making it difficult to understand how these bees use open vegetation environments. The aim of this study was to evaluate the influence of landscape structure on species abundance and composition of Euglossini bees in naturally heterogeneous savanna landscapes. Nine sites were sampled monthly using six traps with chemical baits. Three aromatic essences (eucalyptol, methyl salicylate and vanillin) were used to attract the Euglossini. Surrounding environmental conditions were measured using three independent variables, calculated in multiple scales: index of local vegetation and two landscape indices (Shannon Diversity and area-weighted shape). We compared the competing hypotheses through model selection based on Second-order Akaike Information Criterion (AICc). The four competing hypothesis were: (1) The local vegetation complexity favors Euglossini bees species richness and/or abundance (local vegetation hypothesis); (2) The proportion of the native vegetation types favors Euglossini bees species richness and/or abundance (habitat amount hypothesis); (3) Higher landscape diversity shall increase species richness of Euglossini bees (landscape heterogeneity hypothesis); (4) More complex landscape configuration shall favor the Euglossini bees richness and/or abundance (landscape heterogeneity hypothesis). We sampled 647 individuals belonging to six species of two distinct genera. Our results support the habitat amount hypothesis since bees’ abundance was strongly related with the proportion of habitat in the surrounding landscape. This may be related to the availability of floral and nesting resources in some types of savanna vegetation.

Effect of habitat fragmentation on ranging behavior of white-headed langurs in limestone forests in Southwest China

Primates ◽  
2017 ◽  
Vol 58 (3) ◽  
pp. 423-434 ◽  
Author(s):  
Zhonghao Huang ◽  
Peisong Yuan ◽  
Henglian Huang ◽  
Xiaoping Tang ◽  
Weijian Xu ◽  
...  
Keyword(s):  
Habitat Fragmentation ◽  
Southwest China ◽  
Ranging Behavior

scholarly journals Landscape structure shapes the diversity of tree seedlings at multiple spatial scales in a fragmented tropical rainforest

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0253284
Author(s):  
Sergio Nicasio-Arzeta ◽  
Isela E. Zermeño-Hernández ◽  
Susana Maza-Villalobos ◽  
Julieta Benítez-Malvido
Keyword(s):  
Landscape Structure ◽  
Secondary Forest ◽  
Spatial Scales ◽  
Landscape Composition ◽  
Landscape Configuration ◽  
Secondary Forests ◽  
Tree Seedling ◽  
Forest Patches ◽  
Β Diversity ◽  
Α Diversity

The maintenance of seedling diversity of animal-dispersed tree species is fundamental for the structure and function of forest patches in fragmented tropical rainforests. Nonetheless, the effects of landscape structure at different spatial scales on α- and β-diversity of tree seedling communities are recently explored. Using a multi-scale approach, we assessed the relative effect of landscape composition and configuration on α- and β-diversity of animal-dispersed seedlings within 16 forest patches in the Lacandona rainforest, Mexico. We assessed these effects at 13 spatial scales (from 300 to 1500 m radius, at 100 m intervals) for three metrics of effective number of species considering α- and β-diversity. We found that α-diversity was largely affected by landscape composition and β-diversity by landscape configuration. On the one hand, the amount of secondary forest influenced α-diversity. Additionally, species richness increased in landscapes with highly aggregated forest patches. On the other hand, β-diversity was affected positively by forest fragmentation and negatively by the edge contrast of forest patches with the surrounding matrix. Our findings indicate that landscape configuration is a strong driver of seedling diversity in highly deforested rainforests. Promoting forest patches and secondary forests through payment for ecosystem services’ programs, favoring matrix quality within land-sharing schemes of smallholder agriculture and secondary forest management, and identifying restoration opportunities for assisted or unassisted natural regeneration are urgently needed for conservation of seedling diversity in human-modified tropical landscapes.

scholarly journals Effects of habitat fragmentation and human disturbance on the population dynamics of the Yunnan snub-nosed monkey from 1994 to 2016

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6633 ◽  
Author(s):  
Xumao Zhao ◽  
Baoping Ren ◽  
Dayong Li ◽  
Zuofu Xiang ◽  
Paul A. Garber ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Dynamics ◽  
Habitat Fragmentation ◽  
Population Size ◽  
Linear Models ◽  
Conservation Strategies ◽  
Source Population ◽  
Forest Patches ◽  
Current Conservation ◽  
Conservation Policies

In this study, we integrate data from field investigations, spatial analysis, genetic analysis, and Generalized Linear Models (GLMs) to evaluate the effects of habitat fragmentation on the population dynamics, genetic diversity, and range shifts in the endangered Yunnan snub-nosed monkey (Rhinopithecus bieti). The results indicate that from 1994 to 2016, R. bieti population size increased from less than 2,000 to approximately 3,000 individuals. A primary factor promoting population recovery was the establishment of protected nature reserves. We also found that subpopulation growth rates were uneven, with the groups in some areas, and the formation of new groups. Both the fragmentation index, defined as the ratio of the number of forest patches to the total area of forest patches (e.g., increased fragmentation), and increasing human population size had a negative effect on population growth in R. bieti. We recommend that government conservation plans prioritize the protection of particular R. bieti populations, such as the Baimei and Jisichang populations, which have uncommon haplotypes. In addition, effective conservation strategies need to include an expansion of migration corridors to enable individuals from larger populations such as Guyoulong (Guilong) to serve as a source population to increase the genetic diversity of smaller R. bieti subpopulations. We argue that policies designed to protect endangered primates should not focus solely on total population size but also need to determine the amount of genetic diversity present across different subpopulations and use this information as a measure of the effectiveness of current conservation policies and the basis for new conservation policies.

scholarly journals Landscape heterogeneity buffers biodiversity of meta-food-webs under global change through rescue and drainage effects

2020 ◽  
Author(s):  
Remo Ryser ◽  
Myriam R. Hirt ◽  
Johanna Häussler ◽  
Dominique Gravel ◽  
Ulrich Brose
Keyword(s):  
Habitat Fragmentation ◽  
Food Web ◽  
Food Webs ◽  
Landscape Heterogeneity ◽  
Landscape Connectivity ◽  
Biodiversity Loss ◽  
Mechanistic Explanation ◽  
Trophic Levels ◽  
Drainage Effect ◽  
Landscape Homogenization

SummaryThe impacts of habitat fragmentation and eutrophication on biodiversity have been studied in different scientific realms. Metacommunity research1–5 has shown that reduction in landscape connectivity may cause biodiversity loss in fragmentated landscapes. Food-web research addressed how eutrophication increases biomass accumulations at high trophic levels causing the breakdown of local biodiversity 6–9. However, there is very limited understanding of their cumulative impacts as they could amplify or cancel each other. Here, we show with simulations of meta-food-webs that landscape heterogeneity provides a buffering capacity against increasing nutrient eutrophication. An interaction between eutrophication and landscape homogenization precipitates the decline of biodiversity. We attribute our results to two complementary mechanisms related to source and sink dynamics. First, the “rescue effect” maintains local biodiversity by rapid recolonization after a local crash in population densities. Second, the “drainage effect” allows a more uniform spreading of biomass across the landscape, reducing overall interaction strengths and therefore stabilizing dynamics. In complex food webs on large spatial networks of habitat patches, these effects yield systematically higher biodiversity in heterogeneous than in homogeneous landscapes. Our meta-food-web approach reveals a strong interaction between habitat fragmentation and eutrophication and provides a mechanistic explanation of how landscape heterogeneity promotes biodiversity.

Determinants of daily path length in black and gold howler monkeys (Alouatta caraya) in northeastern Argentina

2016 ◽  
Vol 78 (8) ◽  
pp. 825-837 ◽  
Author(s):  
Mariana Raño ◽  
Martin M. Kowalewski ◽  
Alexis M. Cerezo ◽  
Paul A. Garber
Keyword(s):  
Path Length ◽  
Alouatta Caraya ◽  
Howler Monkeys ◽  
Daily Path Length ◽  
Northeastern Argentina

scholarly journals Comparative home range size and habitat selection in provisioned and non-provisioned long-tailed macaques (Macaca fascicularis) in Baluran National Park, East Java, Indonesia

2020 ◽  
Vol 89 (4) ◽  
pp. 393-411
Author(s):  
Malene F. Hansen ◽  
Signe Ellegaard ◽  
Maria M. Moeller ◽  
Floris M. van Beest ◽  
Agustin Fuentes ◽  
...  
Keyword(s):  
Habitat Selection ◽  
Home Range ◽  
Path Length ◽  
National Park ◽  
Macaca Fascicularis ◽  
Home Range Size ◽  
Range Size ◽  
Food Provisioning ◽  
Wet Season ◽  
Daily Path Length

The effect of food provisioning on ranging patterns of long-tailed macaques (Macaca fascicularis) in non-anthropogenic areas is largely unknown, as most published studies have focused on urban macaques. In this study, we quantified habitat selection, daily path length and home range size in long-tailed macaques in Baluran National Park, East Java, Indonesia, comparing a non-provisioned to a provisioned group. To track the groups, we deployed six GPS-collars on females in both groups, of which only two collected data. Home range size (90% Auto-correlated Kernel Density Estimate) was 23 times smaller for the provisioned group (10.62 ha) than the non-provisioned group (249.90 ha). Home range size and area changed from dry to wet season for the non-provisioned group. Provisioned group home range size correlated negatively with number of visitors in the national park. Daily path length was significantly higher for the non-provisioned group. The provisioned group preferred settlements, where most of the provisioning occurred, and avoided areas with invasive acacia (Acacia nilotica). The non-provisioned group also avoided invasive acacia, preferred secondary forest in the dry season and restored savannah in the wet season. Food provisioning can affect macaque spatial ecology, by shaping daily travel length and home range size, and changing patterns of habitat selection. Even tourism in a managed national park, where provisioning is strictly prohibited although not always enforced, has significant consequences for animal behaviour and their natural ecosystems.

scholarly journals Landscape Structure Effects on Bee and Wasp Assemblages in a Semiarid Buffer Zone

2019 ◽  
Vol 76 ◽  
pp. 1-17 ◽  
Author(s):  
Lilian Maria Araujo Flores ◽  
Lorenzo Roberto Sgobaro Zanette ◽  
Danilo Boscolo ◽  
Francisca Soares Araújo
Keyword(s):  
Landscape Structure ◽  
Landscape Heterogeneity ◽  
Buffer Zone ◽  
Spatial Arrangement ◽  
Landscape Composition ◽  
Landscape Configuration ◽  
Resource Limited ◽  
Conservation Actions ◽  
Landscape Units ◽  
Vegetation Loss

Understanding the effects of anthropogenic changes on groups that perform key ecosystem services, such as pollination and pest control, is essential for conservation and maintenance of these groups in landscapes. We aimed to understand how landscape heterogeneity and the natural vegetation loss affect the diversity of bees, wasps and their parasitoids in a resource limited semiarid environment. We sampled bees and wasps that nest in pre-existing cavities in 20 landscapes, for two years, in Ubajara National Park, in northeastern of Brazil. We recorded eleven species of bees, nine of wasps and six of parasitoids in 657 trapnests. Landscape heterogeneity had different effects on bees, wasps and their parasitoids. Landscape configuration had stronger effect than composition. Bee abundance decreased according to the complexity of the spatial arrangement of landscape units, while wasp abundance increased. Our study shows that in semiarid regions some species may have different responses to landscape structure from those found in other regions. The spatial patterns described here have important implications for conservation of these essential biological groups, indicating that conservation actions for these groups should associate both landscape composition and configuration to increase the provision of resources and to facilitate the access to resources throughout the year.

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