scholarly journals Habitat preference and current distribution of Chinese Pangolin (Manis pentadactyla L. 1758) in Dorokha Dungkhag, Samtse, southern Bhutan

2020 ◽  
Vol 12 (11) ◽  
pp. 16424-16433
Author(s):  
Dago Dorji ◽  
Jambay ◽  
Ju Lian Chong ◽  
Tshering Dorji
Keyword(s):  
Current Distribution ◽  
Habitat Preference ◽  
Suitable Habitat ◽  
Burrow Density ◽  
Preferred Habitat ◽  
High Termite ◽  
Different Seasons ◽  
Manis Pentadactyla ◽  
Feeding Activities ◽  
Belt Transect

The Chinese Pangolin (CP), Manis pentadactyla L. is one of the two pangolin species recorded in Bhutan.  Not many studies, however, were carried out on the species in Bhutan.  The present study was carried out to assess the habitat preference and current distribution of CP, Manis pentadactyla in Dorokha Dungkhag, Samtse from January to March 2017.  Belt transect method consisting of 100 x 100 m each was used to assess the habitat preference and estimate burrow density, coupled with an extensive search of indirect signs of pangolin presence (burrows, scat, footprint, scales, scratches) was utilized to determine the current distribution of the CP.  Modelling of habitat was carried out using QGIS and Maxent.  A total of 181 burrows were recorded from 48 plots with burrow density of 0.104 per hectare.  These were mostly distributed in the habitat dominated by needlework trees (Schima wallichii), evergreen broadleaf (Castanopsis hytrix) and shrubs (Viburnum species).  The preferred habitat of the CP was recorded to range from an altitude of 1,300–1,700 m, with highest feeding activities recorded within the periphery of cardamom plantation and adjacent forested area.  A higher burrow density was recorded in humid soils, with high termite presence, and in the vicinity of human settlements.  Habitat modelling revealed that 23.57km2 of the study area was highly suitable and 37.88km2 was a suitable habitat for the species.  Similar studies are suggested to be carried out in other parts of Bhutan in different seasons to better understand the species and its distribution in the country. 

Habitat preference, diet and demography of the smoky mouse, Pseudomys fumeus (Rodentia : Muridae), in south-eastern New South Wales

2003 ◽  
Vol 30 (1) ◽  
pp. 89 ◽  
Author(s):  
Fred Ford ◽  
Andrew Cockburn ◽  
Linda Broome
Keyword(s):  
Habitat Preference ◽  
New South ◽  
New South Wales ◽  
Habitat Choice ◽  
Early Spring ◽  
Suitable Habitat ◽  
Dietary Preference ◽  
Winter Diet ◽  
South Wales ◽  
High Level

The smoky mouse, Pseudomys fumeus, is an endangered rodent for which ecological information is lacking across much of its range. This paper provides the first detailed study of the local diet and habitat preference of P. fumeus since 1980, conducted on the recently discovered Nullica population in New South Wales. Diet and trap-revealed movements were examined in conjunction with 18 characteristics of habitat to determine the factors influencing habitat choice. Multiple logistic regression of habitat variables and capture locations revealed a floristically determined preference for heath habitat characterised by Epacris impressa, Monotoca scoparia, Leptospermum trinervium, Xanthorrhoea spp. and a variety of legumes. Hypogeal fungi and seeds were the most common food items in the diet of P. fumeus. Fungi were most abundant in winter diet, while seeds and fruit became dominant in late spring and summer. The spring and summer preference for ridge-top heath habitats observed in this study is probably the result of this dietary preference. Resident females constituted 71% of the population in early spring. However, there was a severe decline in numbers of female mice during early spring, and resident males also disappeared from the population. Causes of the decline were unclear. Five of eleven males captured during this study were transient, while no transient females were caught. The sudden decline in the study population, combined with the patchy distribution of suitable habitat and high level of male transience, suggests that P. fumeus form a metapopulation in the Nullica region.

scholarly journals The mismatch between location of protected areas and suitable habitat for the Vulnerable taruka Hippocamelus antisensis

Oryx ◽  
2018 ◽  
Vol 53 (4) ◽  
pp. 752-756 ◽  
Author(s):  
Cristina Mata ◽  
Nicolás Fuentes-Allende ◽  
Juan E. Malo ◽  
André Vielma ◽  
Benito A. González
Keyword(s):  
Protected Areas ◽  
Protected Area ◽  
Species Distribution Model ◽  
Human Impacts ◽  
Atacama Desert ◽  
Distribution Model ◽  
Suitable Habitat ◽  
Core Habitat ◽  
Preferred Habitat ◽  
Educational Programmes

AbstractProtected areas help to decrease human impacts on threatened mammals but do not always include species’ core habitats. Here we focus on the Vulnerable taruka Hippocamelus antisensis near the Atacama Desert, Chile, a population that is mainly threatened by interactions with local human communities. We develop a species distribution model for taruka and assess the contribution of protected areas to safeguarding its preferred habitat. From sightings (collected during 2004–2015), absence records (collected in 2014), and environmental variables, we determined that taruka habitat is scarce, highly fragmented and limited to humid areas. Only 7.7–11.2% of the taruka's core habitat is under protection. We recommend the establishment of a protected area in the south of Arica-Parinacota district, an area without settlements that lies within the taruka's core habitat, along with educational programmes, fencing of crops, and inclusion of communities in decision-making in areas where farmer–taruka interactions are negative.

scholarly journals Speciation: more likely through a genetic or through a learned habitat preference?

2005 ◽  
Vol 272 (1571) ◽  
pp. 1455-1463 ◽  
Author(s):  
J.B Beltman ◽  
J.A.J Metz
Keyword(s):  
Reproductive Isolation ◽  
Habitat Preference ◽  
Sympatric Speciation ◽  
Genetic Mechanism ◽  
Dynamical Analysis ◽  
Disruptive Selection ◽  
Single Population ◽  
Preferred Habitat ◽  
Simultaneous Evolution ◽  
Evolution Proceeds

A problem in understanding sympatric speciation is establishing how reproductive isolation can arise when there is disruptive selection on an ecological trait. One of the solutions that has been proposed is that a habitat preference evolves, and that mates are chosen within the preferred habitat. We present a model where the habitat preference can evolve either by means of a genetic mechanism or by means of learning. Employing an adaptive-dynamical analysis, we show that evolution proceeds either to a single population of specialists with a genetic preference for their optimal habitat, or to a population of generalists without a habitat preference. The generalist population subsequently experiences disruptive selection. Learning promotes speciation because it increases the intensity of disruptive selection. An individual-based version of the model shows that, when loci are completely unlinked and learning confers little cost, the presence of disruptive selection most probably leads to speciation via the simultaneous evolution of a learned habitat preference. For high costs of learning, speciation is most likely to occur via the evolution of a genetic habitat preference. However, the latter only happens when the effect of mutations is large, or when there is linkage between genes coding for the different traits.

scholarly journals Identification of Priority Sites to Support Management of Commercially Important Sea Cucumber Species by Applying Infomap and Habitat Filters to Larval Dispersal Data

2021 ◽  
Vol 7 ◽  
Author(s):  
Josephine Dianne L. Deauna ◽  
Kevin Matthew B. Yatco ◽  
Cesar L. Villanoy ◽  
Marie Antonette Juinio-Meñez
Keyword(s):  
Larval Dispersal ◽  
Sea Cucumber ◽  
Natural Populations ◽  
Detection Algorithm ◽  
Southwest Monsoon ◽  
Suitable Habitat ◽  
Northeast Monsoon ◽  
Group Iii ◽  
Group I ◽  
Different Seasons

Stocks of commercially valuable sea cucumber species have declined in most tropical countries, which supply majority of the global demand. This work aimed to locate priority sites for the management of Holothuria scabra and Stichopus horrens in the western central Philippines. A passive larval dispersal model was run under four monsoonal regimes (Northeast monsoon, dry-transition, Southwest monsoon, and early Northeast monsoon), and the results subjected to the Infomap network detection algorithm. Three clusters of closely related geographical nodes were identified [southeastern Palawan (Group I), western Panay and eastern Mindoro (Group II), and northern and western Palawan with western Mindoro (Group III)]. Remotely sensed habitat data were used to parameterize the degree of connectivity observed among sites (H. scabra spawning and settlement requires the presence of seagrass and mangrove, while S. horrens requires corals and seagrass). Local retention, self-recruitment, settlement success and sink diversity were then calculated for each node with suitable habitat. The locations were ranked according to each metric and those with higher larval export rates, a higher diversity of larval sources and a high degree of successful larval contribution to other sites were deemed crucial for the management of wild populations. Sixteen high-priority sites were identified, distributed mainly along northern Palawan and western Panay. Six sites were common for both species at different seasons, and no single location fulfilled all stated criteria across the four seasons and both sea cucumber species considered. The priority sites for management could serve as broodstock selection and juvenile restocking areas for aquaculture production clusters, which when properly implemented, could lead to an increase in sea cucumber production and contribute to natural populations. On a broader scale, the designation of closely related clusters and incorporation of habitat requirements to dispersal data provided critical input for the delineation of ecologically meaningful management units for sea cucumbers within the region.

scholarly journals Predicting the Current and Future Suitable Habitat Distribution of Swimming Crab (Portunus trituberculatus) using the Species Distribution Model under Climate Change

2021 ◽  
Author(s):  
Xinyu Liu ◽  
Xiaolu Han ◽  
Zhiqiang Han
Keyword(s):  
Climate Change ◽  
Species Distribution ◽  
Species Distribution Model ◽  
Seawater Temperature ◽  
The Yellow Sea ◽  
Distribution Model ◽  
Portunus Trituberculatus ◽  
Suitable Habitat ◽  
Different Seasons ◽  
Rcp 8.5

Species have shown their habital variations in responding to climate change, especially during the spring and summer spawning seasons. The species distribution model (SDM) is considered the most favorable tool to study the potential effects of climate change on species distribution. Therefore, we developed the ensemble SDM to predict the changes in species distribution of Portunus trituberculatus among different seasons in 2050 and 2100 under the climate scenarios RCP4.5 and RCP8.5. The results of SDM indicate that the distribution of this species will move northward and have obviouse seasonal variations. Meanwhile, the suitable habitat for the species will be significantly reduced in summer, with loses rates ranging from 45.23% (RCP4.5) to 88.26% (RCP.8.5) by 2100s. Habitat reduction will mainly occur in the East China Sea and southern part of the Yellow Sea, while there will be a small increase in the northern Bohai Sea. These findings will be important to manage the ecosystem and fishery, provide an information forecast of this species in the future, and maintain species diversity if the seawater temperature rises.

scholarly journals The influence of habitat preference on longitudinal population composition and distribution of Groupers (Serranidae) in Chumbe Island Coral Park, Zanzibar, Tanzania

2021 ◽  
Vol 19 (2) ◽  
pp. 1-16
Author(s):  
Caroline Daley
Keyword(s):  
Population Health ◽  
Habitat Preference ◽  
Population Distribution ◽  
Species Abundance ◽  
Slope Position ◽  
Population Composition ◽  
Realized Niche ◽  
Preferred Habitat ◽  
Cephalopholis Argus ◽  
Substrate Depth

A survey of six common grouper (Serranidae) species was conducted on both the western protected and eastern unprotected reefs around Chumbe Island, Zanzibar. Species, estimated maturity, and habitat were recorded using standardized categories. Fundamental niche and general habitat preference were extrapolated based on observed realized niche and qualified based on substrate, depth, slope position, and general reef region. Taking habitat preference into account, abundance and biomass density of serranid populations were compared between locations on the reef in order to best account for how habitat influences distribution and population health. The results of this study provide depth to previous research on the protected reef and indicate noteworthy shifts in population composition between 2014 and 2018 that favour species with less specified habitat preference, such as Aethaloperca rogaa and Cephalopholis argus. Surveys of Chumbe’s nearby unprotected eastern reef indicate low levels of species abundance, which this study hypothesizes is the result of inappropriate habitat structure, increased fishing pressure, and decreased population health within the MPA. Ultimately, this study suggests that MPAs do not protect all species equally, and habitat preference must be taken into account when assessing MPA effectiveness at protecting different species. Indeed, especially as serranid habitat faces continued degradation, serranid conservation will depend even more on protection of each species’ preferred habitat in coral systems. As such, assessing serranid populations as a whole fails to capture the changes in population distribution and composition that is occurring between species, which may be more indicative of shifts and disturbances in the ecosystem.

Metapopulations and their spatial dynamics

2007 ◽  
Author(s):  
Sean Nee
Keyword(s):  
Local Population ◽  
Spatial Dynamics ◽  
Suitable Habitat ◽  
Dynamical Process ◽  
Demographic Stochasticity ◽  
Population Extinction ◽  
Local Populations ◽  
Preferred Habitat ◽  
Tree Falls

The study of metapopulation dynamics has had a profound impact on our understanding of how species relate to their habitats. A natural, if naïve, set of assumptions would be that species are to be found wherever there is suitable habitat that they can get to; that species will rarely, if ever, be found in unsuitable habitat; that they will be most abundant in their preferred habitat; that species can be preserved as long as a good-size chunk of suitable habitat is conserved for them; and that destruction of a species’ habitat is always detrimental for its abundance. We will see that none of these reasonable-sounding assumptions is necessarily true. Metapopulation biology is a vast field, so to focus this chapter I will be guided partly by questions relevant to conservation biology. There are two important kinds of metapopulation. The so-called Levins metapopulation idea (Levins, 1970) is illustrated in Figure 4.1. It is imagined that patches of habitat suitable for a species are distributed across a landscape. Over time, there is a dynamical process of colonization and extinction: the colonization of empty patches by occupied patches sending out colonizing propagules and the extinction of local populations on occupied patches. This extinction can occur for a number of reasons. Small populations are prone to extinction just by the chance vagaries of the environment, reproduction, and death—environmental and demographic stochasticity (May, 1974b; Lande et al., 2003). An example of a species for which this is important is the Glanville fritillary butterfly (Melitaea cinxia), which has been extensively studied by Hanski and colleagues (Hanski, 1999). This Scandinavian butterfly lives in dry meadows which are small and patchily distributed. Another reason for local population extinction is that the habitat patch itself may be ephemeral. For example, wood-rotting fungi will find that their patch ultimately rots completely away (Siitonen et al., 2005) and epiphytic mosses will ultimately find that their tree falls over (Snall et al., 2005). The second type of metapopulation consists of local populations connected by dispersal, but without the extinction of the local populations.

scholarly journals Improved grazing activity of dairy heifers in shaded tropical grasslands

2017 ◽  
Vol 47 (2) ◽  
Author(s):  
Andréia Cristina Tavares de Mello ◽  
Roberta Aparecida Carnevalli ◽  
Luciano Shozo Shiratsuchi ◽  
Bruno Carneiro e Pedreira ◽  
Luciano Bastos Lopes ◽  
...  
Keyword(s):  
Production Systems ◽  
Average Weight ◽  
Daily Routine ◽  
Mato Grosso ◽  
Grazing Behavior ◽  
Dairy Heifers ◽  
Tropical Grasslands ◽  
Different Seasons ◽  
Feeding Activities ◽  
Hot Weather

ABSTRACT: Trees in the production systems can effectively reduce hot weather-induced stress in the Brazilian Midwest. High temperatures cause changes in animals daily routine, and trees into pastures can promote benefits. The aim of this research was to evaluate the behavior of dairy heifers in silvopastoral systems in the state of Mato Grosso, Brazil. A herd of 24 crossbreed heifers (3/4 and 7/8 Holstein/Zebu), 350kg average weight, was evaluated over three seasons. Piatã grass was managed under three shade levels: full-sun, moderate-shade, and intensive-shade provided by 10 to 12m high Eucalyptus trees. Behavior data were collected every 15 minutes from 8:30h to 16h. Shade availability significantly impacted heifer behavior, mainly affecting grazing frequency and time during the hottest hours. Grazing behavior was affected by shade levels during the different seasons. Heifers showed preferred grazing times. Heifers in the intensive-shade system visited shady areas during the hottest hours throughout the seasons. Heifers in the full sun-system avoided grazing during the warmer times, ceasing feeding activities. Our results from the Brazilian Midwest showed that shade availability causes breed heifers to change their daily routine.

scholarly journals The Endangered giant nuthatch Sitta magna: population size, habitat availability and the implications for its conservation in Thailand

Oryx ◽  
2021 ◽  
pp. 1-7
Author(s):  
Daphawan Khamcha ◽  
Rongrong Angkaew ◽  
Andrew J. Pierce ◽  
George A. Gale
Keyword(s):  
Basal Area ◽  
Dry Forest ◽  
Habitat Characteristics ◽  
Western China ◽  
Suitable Habitat ◽  
Thai Population ◽  
Point Count ◽  
Pinus Kesiya ◽  
Large Tree ◽  
Preferred Habitat

Abstract Available habitat and hence the global population of the Endangered giant nuthatch Sitta magna, restricted to lower montane habitats of south-western China, eastern Myanmar and northern Thailand, remains poorly quantified. Thailand is the only portion of the species’ range for which there is a population estimate. To obtain a more precise estimate of the Thai population and clarify the extent and characteristics of suitable habitat remaining, we conducted 335 point-count surveys at 67 points across eight localities during November 2019–February 2020. We estimated abundance and identified preferred habitat characteristics using N-mixture models, and created suitable habitat maps based on data from surveys and remote sensing. Our estimate for Thailand was 578 (95% CI 391–854) individuals based on a density of 3.7 (95% CI 2.5–5.5) individuals/km2 in 156 km2 of suitable habitat. The giant nuthatch prefers dry forest with a large amount of mature native or planted pine Pinus kesiya and with a large tree basal area and an open canopy. Our estimate of suitable habitat remaining was less than previously reported and thus the population has probably decreased, although most of this habitat is within protected areas. Habitats for the species in Thailand have a stronger level of protection than in Myanmar and China, although habitat in China remains unquantified. We recommend further research in Myanmar and China, which may hold the majority of available habitat for the giant nuthatch. For long-term management, detailed study of the association of the giant nuthatch with pine plantations is required.

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