scholarly journals Modelling the distribution and relative abundance of feral camels in the Northern Territory using count data

2010 ◽  
Vol 32 (1) ◽  
pp. 21 ◽  
Author(s):  
S. R. McLeod ◽  
A. R. Pople
Keyword(s):  
Relative Abundance ◽  
Habitat Suitability ◽  
Additive Model ◽  
Aerial Survey ◽  
Northern Territory ◽  
Suitable Habitat ◽  
Habitat Association ◽  
Generalised Additive Model ◽  
Suitability Maps ◽  
Index Of Abundance

The objectives of this study were to predict the potential distribution, relative abundance and probability of habitat use by feral camels in southern Northern Territory. Aerial survey data were used to model habitat association. The characteristics of ‘used’ (where camels were observed) v. ‘unused’ (pseudo-absence) sites were compared. Habitat association and abundance were modelled using generalised additive model (GAM) methods. The models predicted habitat suitability and the relative abundance of camels in southern Northern Territory. The habitat suitability maps derived in the present study indicate that camels have suitable habitat in most areas of southern Northern Territory. The index of abundance model identified areas of relatively high camel abundance. Identifying preferred habitats and areas of high abundance can help focus control efforts.

scholarly journals Habitat suitability maps for juvenile tri-spine horseshoe crabs in Japanese intertidal zones: A model approach using unmanned aerial vehicles and the Structure from Motion technique

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0244494
Author(s):  
Akihiko Koyama ◽  
Taiga Hirata ◽  
Yuki Kawahara ◽  
Hiroki Iyooka ◽  
Haruka Kubozono ◽  
...  
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Structure From Motion ◽  
Habitat Suitability ◽  
Tidal Range ◽  
Suitable Habitat ◽  
Intertidal Zones ◽  
Intertidal Flats ◽  
Aerial Vehicles ◽  
Short Period ◽  
Suitability Maps

The tri-spine horseshoe crab, Tachypleus tridentatus, is a threatened species that inhabits coastal areas from South to East Asia. A Conservation management system is urgently required for managing its nursery habitats, i.e., intertidal flats, especially in Japan. Habitat suitability maps are useful in drafting conservation plans; however, they have rarely been prepared for juvenile T. tridentatus. In this study, we examined the possibility of constructing robust habitat suitability models (HSMs) for juveniles based on topographical data acquired using unmanned aerial vehicles and the Structure from Motion (UAV-SfM) technique. The distribution data of the juveniles in the Tsuyazaki and Imazu intertidal flats from 2017 to 2019 were determined. The data were divided into a training dataset for HSM construction and three test datasets for model evaluation. High accuracy digital surface models were built for each region using the UAV-SfM technique. Normalized elevation was assessed by converting the topographical models that consider the tidal range in each region, and the slope was calculated based on these models. Using the training data, HSMs of the juveniles were constructed with normalized elevation and slope as the predictor variables. The HSMs were evaluated using the test data. The results showed that HSMs exhibited acceptable discrimination performance for each region. Habitat suitability maps were built for the juveniles in each region, and the suitable areas were estimated to be approximately 6.1 ha of the total 19.5 ha in Tuyazaki, and 3.7 ha of the total 7.9 ha area in Imazu. In conclusion, our findings support the usefulness of the UAV-SfM technique in constructing HSMs for juvenile T. tridentatus. The monitoring of suitable habitat areas for the juveniles using the UAV-SfM technique is expected to reduce survey costs, as it can be conducted with fewer investigators over vast intertidal zones within a short period of time.

scholarly journals A reconnaissance survey for Collared Pika (Ochotona collaris) in northern Yukon

2019 ◽  
Vol 133 (2) ◽  
pp. 130 ◽  
Author(s):  
Sydney G. Cannings ◽  
Thomas S. Jung ◽  
Jeffrey H. Skevington ◽  
Isabelle Duclos ◽  
Saleem Dar
Keyword(s):  
Habitat Suitability ◽  
New Records ◽  
Species Distribution Modelling ◽  
Aerial Survey ◽  
Suitable Habitat ◽  
Distribution Modelling ◽  
Reconnaissance Survey ◽  
Ochotona Collaris ◽  
Northern Portion ◽  
Richardson Mountains

Collared Pika (Ochotona collaris) is a cold-adapted Beringian species that occurs on talus slopes and is sensitive to climate warming. Collared Pikas are patchily distributed throughout the sub-Arctic mountains of northwestern Canada and Alaska; however, information on their occurrence in the northern part of their distributional range is limited. In particular, no survey information is known from the southern Richardson Mountains and the Nahoni Mountains. We conducted aerial- and ground-based surveys to document Collared Pika occurrence and general habitat suitability in northern Yukon. We flew 505 km of aerial survey (not including ferrying to targetted survey areas) and performed ground surveys at 22 sites within the Richardson Mountains (including a portion of Dàadzàii Vàn Territorial Park) and the Nahoni Mountains in and adjacent to Ni’iinlii Njik (Fishing Branch) Territorial Park. Overall, suitable habitat for Collared Pikas was patchy in the mountains of northern Yukon—talus was sparse and many patches of talus appeared to be unsuitable. Collared Pikas were detected at eight of 22 (36%) sites visited, representing important new records for the species in the northern portion of their range. Our reconnaissance provides a first approximation of habitat suitability for Collared Pikas of the mountains of northern Yukon, as well as new records for the species in the region. These data are useful in better determining the contemporary distribution of Collared Pika through species distribution modelling, and may serve to identify areas for more detailed survey and monitoring initiatives for this climate-sensitive mammal.

An evaluation of transect, plot and aerial survey techniques to monitor the spatial pattern and status of the bilby (Macrotis lagotis) in the Tanami Desert

2005 ◽  
Vol 32 (1) ◽  
pp. 43 ◽  
Author(s):  
Richard Southgate ◽  
Rachel Paltridge ◽  
Pip Masters ◽  
Theresa Nano
Keyword(s):  
Spatial Pattern ◽  
Relative Abundance ◽  
False Negative ◽  
Ground Truth ◽  
Aerial Survey ◽  
Northern Territory ◽  
Survey Techniques ◽  
Survey Technique ◽  
Central Australia ◽  
Tracking Surface

We evaluated three monitoring techniques to determine the spatial pattern and relative abundance of the bilby (Macrotis lagotis) in the Tanami Desert, Northern Territory. All the methods examined relied on the identification of animal sign (foot imprints or diggings) to indicate the presence of a species. With fixed transects, a 10-km prepared tracking surface was monitored regularly using an all-terrain vehicle. With random plots, an unprepared tracking surface within a 200 × 300 m area was searched on foot for sign of the species. A helicopter was used in an aerial survey to identify bilby diggings from an altitude of 15–20 m while travelling at a speed of 30–40 knots along a predefined transect. The results for each method were stratified in relation to latitude and substrate to facilitate comparison of the efficacy of each technique. The fixed transects returned the least number of bilby records for most effort. The aerial transect technique resulted in few (<4%) false negative records but a sizeable (42%) number of false positive records. It is suggested that the aerial survey technique combined with ground-truth survey plots would provide reliable information on the extent of occurrence and status of the bilby in the remote spinifex deserts of central Australia.

Predicting bycatch hotspots based on suitable habitat derived from fishery-independent data

2020 ◽  
Vol 641 ◽  
pp. 159-175
Author(s):  
J Runnebaum ◽  
KR Tanaka ◽  
L Guan ◽  
J Cao ◽  
L O’Brien ◽  
...  
Keyword(s):  
Habitat Suitability ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Gulf Of Maine ◽  
Homarus Americanus ◽  
Management Tool ◽  
American Lobster ◽  
Suitable Habitat ◽  
Climate Conditions ◽  
Suitability Index

Bycatch remains a global problem in managing sustainable fisheries. A critical aspect of management is understanding the timing and spatial extent of bycatch. Fisheries management often relies on observed bycatch data, which are not always available due to a lack of reporting or observer coverage. Alternatively, analyzing the overlap in suitable habitat for the target and non-target species can provide a spatial management tool to understand where bycatch interactions are likely to occur. Potential bycatch hotspots based on suitable habitat were predicted for cusk Brosme brosme incidentally caught in the Gulf of Maine American lobster Homarus americanus fishery. Data from multiple fisheries-independent surveys were combined in a delta-generalized linear mixed model to generate spatially explicit density estimates for use in an independent habitat suitability index. The habitat suitability indices for American lobster and cusk were then compared to predict potential bycatch hotspot locations. Suitable habitat for American lobster has increased between 1980 and 2013 while suitable habitat for cusk decreased throughout most of the Gulf of Maine, except for Georges Basin and the Great South Channel. The proportion of overlap in suitable habitat varied interannually but decreased slightly in the spring and remained relatively stable in the fall over the time series. As Gulf of Maine temperatures continue to increase, the interactions between American lobster and cusk are predicted to decline as cusk habitat continues to constrict. This framework can contribute to fisheries managers’ understanding of changes in habitat overlap as climate conditions continue to change and alter where bycatch interactions could occur.

scholarly journals Predicting Impacts of Climate Change on Northward Range Expansion of Invasive Weeds in South Korea

Plants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1604
Author(s):  
Sun Hee Hong ◽  
Yong Ho Lee ◽  
Gaeun Lee ◽  
Do-Hun Lee ◽  
Pradeep Adhikari
Keyword(s):  
Climate Change ◽  
South Korea ◽  
Habitat Suitability ◽  
Management Strategies ◽  
Southern Region ◽  
Suitable Habitat ◽  
Invasive Weeds ◽  
Northern Regions ◽  
Suitable Habitats ◽  
Control And Management

Predicting the distribution of invasive weeds under climate change is important for the early identification of areas that are susceptible to invasion and for the adoption of the best preventive measures. Here, we predicted the habitat suitability of 16 invasive weeds in response to climate change and land cover changes in South Korea using a maximum entropy modeling approach. Based on the predictions of the model, climate change is likely to increase habitat suitability. Currently, the area of moderately suitable and highly suitable habitats is estimated to be 8877.46 km2, and 990.29 km2, respectively, and these areas are expected to increase up to 496.52% by 2050 and 1439.65% by 2070 under the representative concentration pathways 4.5 scenario across the country. Although habitat suitability was estimated to be highest in the southern regions (<36° latitude), the central and northern regions are also predicted to have substantial increases in suitable habitat areas. Our study revealed that climate change would exacerbate the threat of northward weed invasions by shifting the climatic barriers of invasive weeds from the southern region. Thus, it is essential to initiate control and management strategies in the southern region to prevent further invasions into new areas.

Growth performance of Acheta domesticus and Gryllus bimaculatus production reared under improvised cage system for increased returns and food security

2020 ◽  
pp. 1-10
Author(s):  
C.A. Ngonga ◽  
C.O. Gor ◽  
E.A. Okuto ◽  
M.A. Ayieko
Keyword(s):  
Relative Humidity ◽  
Growth Performance ◽  
Additive Model ◽  
Acheta Domesticus ◽  
Cotton Wool ◽  
Conventional System ◽  
Gryllus Bimaculatus ◽  
Generalised Additive Model ◽  
Cage System ◽  
Significant Difference

Cricket farming is emerging as a new venture in Kenya poised to help alleviate protein deficiency and improve household living standards. However, competing, limited and unaffordable rearing systems constrain productivity and optimisation of this new enterprise. This study sought to evaluate the growth performance of Acheta domesticus and Gryllus bimaculatus reared in improvised cage system to assess its technical effectiveness. Twenty-day old of both species of crickets were separately reared in improvised and conventional cage systems for comparison purposes. Whereas an improvised cage system is a set of structure devised using locally available materials especially where the standard materials are limited, a conventional cage system is a set of structure made of standard and ordinary materials. The improvised system comprised of bamboo hideouts, clean scrap blankets for drinking and laying, cut bamboo stem as drinking platter and the plywood-based cages while conventional system comprised of egg carton hideouts, cotton-wool for drinking and laying, plastic petri-dishes, and plastic buckets. Each group of crickets (100 live crickets) was daily provided with equal amount of feed and water. Average weekly temperature and relative humidity profiles were recorded using HOBO data loggers. Further, 49 live crickets per treatment were randomly sampled and weighed weekly. Generalised additive model and analysis of variance were adopted to model the data therefrom using R. The cage system had a significant effect on the growth performance of the crickets. The mean weight of the cricket species differed, but not the interaction with the cage system. Similarly, species, temperature and relative humidity also influenced the growth performance. Compared to the conventional system, improvised cage system showed better results in realising high cricket productivity though there was no significant difference in growth performance between the two systems. The focus therefore should be to evaluate the egg productivity in scrap blanket in relation to cotton wool and cost effectiveness in improvised system to inform future farm decisions.

scholarly journals Lowland tapir distribution and habitat loss in South America

2015 ◽  
Author(s):  
Jose Luis Passos Cordeiro ◽  
José MV Fragoso ◽  
Danielle Crawshaw ◽  
Luiz Flamarion B Oliveira
Keyword(s):  
South America ◽  
Protected Areas ◽  
Habitat Loss ◽  
Habitat Suitability ◽  
Distribution Patterns ◽  
Distribution Models ◽  
Potential Habitat ◽  
Geographical Regions ◽  
Suitability Maps ◽  
Complex Relationships

The development of species distribution models (SDMs) can help conservation efforts by generating potential distributions and identifying areas of high environmental suitability for protection. Our study presents a rigorously derived distribution and habitat map for lowland tapir in South America. We also describe the potential habitat suitability of various geographical regions and habitat loss, inside and outside of protected areas network. Two different SDM approaches, MAXENT and ENFA, produced relative different Habitat Suitability Maps for the lowland tapir. While MAXENT was efficient at identifying areas as suitable or unsuitable, it was less efficient (when compared to the results by ENFA) at identifying the gradient of habitat suitability. MAXENT is a more multifaceted technique that establishes more complex relationships between dependent and independent variables. Our results demonstrate that for at least one species, the lowland tapir, the use of a simple consensual approach (average of ENFA and MAXENT models outputs) better reflected its current distribution patterns. The Brazilian ecoregions have the highest habitat loss for the tapir. Cerrado and Atlantic Forest account for nearly half (48.19%) of the total area lost. The Amazon region contains the largest area under protection, and the most extensive remaining habitat for the tapir, but also showed high levels of habitat loss outside protected areas, which increases the importance of support for proper management.

scholarly journals Challenges in updating habitat suitability models: An example with the lesser prairie-chicken

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0256633
Author(s):  
Catherine S. Jarnevich ◽  
Pairsa N. Belamaric ◽  
Kent Fricke ◽  
Mike Houts ◽  
Liza Rossi ◽  
...  
Keyword(s):  
Land Cover ◽  
Habitat Suitability ◽  
Negative Relationship ◽  
Suitable Habitat ◽  
Habitat Suitability Model ◽  
Current Information ◽  
Land Cover Data ◽  
Prairie Chicken ◽  
Anthropogenic Development ◽  
Iteration Model

Habitat loss from land-use change is one of the top causes of declines in wildlife species of concern. As such, it is critical to assess and reassess habitat suitability as land cover and anthropogenic features change for both monitoring and developing current information to inform management decisions. However, there are obstacles that must be overcome to develop consistent assessments through time. A range-wide lek habitat suitability model for the lesser prairie-chicken (Tympanuchus pallidicinctus), currently under review by the U. S. Fish and Wildlife Service for potential listing under the Endangered Species Act, was published in 2016. This model was based on lek data from 2002 to 2012, land cover data ranging from 2001 to 2013, and anthropogenic features from circa 2011, and has been used to help guide lesser prairie-chicken management and anthropogenic development actions. We created a second iteration model based on new lek surveys (2015 to 2019) and updated predictors (2016 land cover and cleaned/updated anthropogenic data) to evaluate changes in lek suitability and to quantify current range-wide habitat suitability. Only three of 11 predictor variables were directly comparable between the iterations, making it difficult to directly assess what predicted changes resulted from changes in model inputs versus actual landscape change. The second iteration model showed a similar positive relationship with land cover and negative relationship with anthropogenic features to the first iteration, but exhibited more variation among candidate models. Range-wide, more suitable habitat was predicted in the second iteration. The Shinnery Oak Ecoregion, however, exhibited a loss in predicted suitable habitat that could be due to predictor source changes. Iterated models such as this are important to ensure current information is being used in conservation and development decisions.

scholarly journals Vector distribution and transmission risk of the Zika virus in South and Central America

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7920
Author(s):  
Sarah Cunze ◽  
Judith Kochmann ◽  
Lisa K. Koch ◽  
Elisa Genthner ◽  
Sven Klimpel
Keyword(s):  
South America ◽  
Central America ◽  
Zika Virus ◽  
Habitat Suitability ◽  
Virus Transmission ◽  
Transmission Risk ◽  
Eastern Coast ◽  
Suitable Habitat ◽  
Virus Infections ◽  
Vector Species

Background Zika is of great medical relevance due to its rapid geographical spread in 2015 and 2016 in South America and its serious implications, for example, certain birth defects. Recent epidemics urgently require a better understanding of geographic patterns of the Zika virus transmission risk. This study aims to map the Zika virus transmission risk in South and Central America. We applied the maximum entropy approach, which is common for species distribution modelling, but is now also widely in use for estimating the geographical distribution of infectious diseases. Methods As predictor variables we used a set of variables considered to be potential drivers of both direct and indirect effects on the emergence of Zika. Specifically, we considered (a) the modelled habitat suitability for the two main vector species Aedes aegypti and Ae. albopictus as a proxy of vector species distributions; (b) temperature, as it has a great influence on virus transmission; (c) commonly called evidence consensus maps (ECM) of human Zika virus infections on a regional scale as a proxy for virus distribution; (d) ECM of human dengue virus infections and, (e) as possibly relevant socio-economic factors, population density and the gross domestic product. Results The highest values for the Zika transmission risk were modelled for the eastern coast of Brazil as well as in Central America, moderate values for the Amazon basin and low values for southern parts of South America. The following countries were modelled to be particularly affected: Brazil, Colombia, Cuba, Dominican Republic, El Salvador, Guatemala, Haiti, Honduras, Jamaica, Mexico, Puerto Rico and Venezuela. While modelled vector habitat suitability as predictor variable showed the highest contribution to the transmission risk model, temperature of the warmest quarter contributed only comparatively little. Areas with optimal temperature conditions for virus transmission overlapped only little with areas of suitable habitat conditions for the two main vector species. Instead, areas with the highest transmission risk were characterised as areas with temperatures below the optimum of the virus, but high habitat suitability modelled for the two main vector species. Conclusion Modelling approaches can help estimating the spatial and temporal dynamics of a disease. We focused on the key drivers relevant in the Zika transmission cycle (vector, pathogen, and hosts) and integrated each single component into the model. Despite the uncertainties generally associated with modelling, the approach applied in this study can be used as a tool and assist decision making and managing the spread of Zika.

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