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1

Predicting the potential invasive range of raccoon in the world

100%
Farashi A., Naderi M., Safavian S.
Polish Journal of Ecology
|
2016
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tom 64
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nr 4
Invasive alien species are considered to be one of the most important causes for the extinction and the reason for diminishing of the wild native species. Considering that nowadays the raccoon (Procyon lotor, Linnaeus 1758) is found in several European and Asian countries where it can amplification its ranges remarkably, but it is actually native to North and Central America. Here, we use the Maxent model to generate a preliminary map of the potential distribution of the raccoon around the world and enumerate its relative risk of invasion across all countries. In a study, MaxEnt predicted a significantly large area as the eco-climatically suitable habitat for the raccoon in the world. The predicted habitats are consistent with the wide-ranging habitat associations of the raccoon in its well-established sites. The results identified the hotspots of the raccoon invasion and indicated the possible dispersal pathways. Results also showed that both precipitation and temperature variables were strongly correlated with the raccoon distribution and the species would be absent in cold environments with average sub-zero temperatures.
2

Effects of sample size, sample accuracy and environmental variables on predictive performance of MaxEnt model

100%
Li Y., Ding C.
Polish Journal of Ecology
|
2016
|
tom 64
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nr 3
The availability of sample data, together with detailed environmental factors, has fueled a rapid increase in predictive modeling of species geographic distributions and environmental requirements. We founded that MaxEnt model has provided different descriptions of potential distributions based on different sample size, sample accuracy and environmental background. We used six combinations based on three sample data set and two kinds of environmental variables to estimate the potentially suitable areas of Brown Eared Pheasant (Crossoptilon mantchuricum) in MaxEnt model. The results show that the complex variables provided the higher AUC value and accurate potential distribution than simple variables based on the same size of samples. Complicated environmental factors combined with moderate size and accurate sample, can predict better results. The model results were scabrous based on simple environmental factors. Furthermore, big sample size and simple prediction environmental factors will reduce the prediction accuracy, whereas small samples provided a conservative description of ecological niche. Here, we highlighted that considering the big size and high accuracy of sample and many environmental factors of a species to minimize error when attempting to infer potential distributions from current data in MaxEnt model.
3

The impact of climate change on habitat suitability for Artemisia sieberi and Artemisia aucheri (Asteraceae) – a modeling approach

84%
Mousaei Sanjerehei M., Rundel P. W.
Polish Journal of Ecology
|
2017
|
tom 65
|
nr 1
We determined the current potential distribution of Artemisia sieberi and A. aucheri, two important widespread rangeland shrub species in Iran, using bioclimatic variables with and without the addition of elevation (E) to the MaxEnt model. The impact of climate change on the habitat suitability of the Artemisiaspecies was modeled for mid century under the projected climate change of GFDL-ESM2G (RCP2.6) model, a warmer and slightly wetter condition, and CCSM4 (RCP4.5) model, a warmer and drier condition. The results showed that annual precipitation (AP) and temperature annual range (TAR) were the most important drivers of A. aucheri distribution at a regional scale. With the addition of E to the model, we found that E and AP were the most significant factors in determining the habitat suitability of this species. The most significant factors influencing A. sieberi distribution were AP and annual mean temperature (AMT). E was not identified as the important variable influencing A. sieberi distribution when was added to the model in spite of its high correlation to AMT (|r| > 0.8), while AP was the most important, indicating that A. sieberi is less dependent on elevation than A. aucheri. A. aucheri is regarded as a high elevation species (E > 2500 m) which can be distributed in colder and wetter areas as compared to A. sieberi, a mid-elevation species (E < 2500 m). The projected climate change using both models has a much more impact on A. aucheri, potentially driving more losses and fewer gains in climatically suitable habitat of this species as compared to A. sieberi suggesting the adaptation of the later to a wider range of climatic conditions than A. aucheri. The results of the current and future distribution modeling of the Artemisia species is significant in managing susceptible habitats of these species for climate change and for habitat restoration.
4

Ecological niche modeling of invasive plant species according to invasion status and management needs: the case of Chromolaena odorata (Asteraceae) in South Africa

84%
Suarez-Mota M. E., Ortiz E., Villasenor J. L., Espinosa-Garcia F. J.
Polish Journal of Ecology
|
2016
|
tom 64
|
nr 3
The management of invasive plant species (IPS) requires knowledge of areas susceptible to invasion and the origin of the invasive biotypes. Ecological niche models (ENMs) are useful for these purposes, but modeling results depend on the data sources. We propose a synthetic approach to determine the selection of data source areas considering the invasion status of an IPS and management objectives to deal with the IPS. We assessed the importance of data source for ENMs and their projections to invasive areas using Chromolaena odorata, a Neotropical weed, in South Africa where this IPS is invading. We used MaxEnt to perform ENMs using different datasets from C. odorata's native range and from South Africa. We employed reciprocal ENM projections to find the probable native region of the plants invading South Africa. ENMs varied depending on the native area selected as the hypothetical invasion source. The modeling approach using worldwide data was most appropriate for prevention purposes, whereas the modelling approach using data from the Americas was most suitable for estimating invasion-susceptible areas in South Africa. The South African ENM was useful for reciprocal modelling but not for prediction of areas susceptible to invasion. ENM projections from the Americas to South Africa and vice-versa identified two native areas as possible invasion sources (northern Mexico and southern tropical South America). Their concordance with the South African ENM can be useful to search for natural enemies of C. odorata's and to reinforce the identification of invasion-susceptible areas in South Africa. We suggest that the various ENM obtained with the synthetic approach in modeling with different data sources for C. odorata cover the scenarios that depend on management purpose and invasion status for this weed.
5

Land use and land cover change in protected areas: using remote sensing to survey suitable habitats of brown bear Ursus arctos

84%
Farashi A., Parvian N., Najafabadi M. S.
Polish Journal of Ecology
|
2016
|
tom 64
|
nr 3
In recent years, brown bear Ursus arctos populations in Iran have experienced a clear trend of reduction and the species is now officially listed as threatened under provincial legislation. Anthropogenic habitat alteration and increasing human access to previously remote landscapes are potential source of stress for this species in Iran. Therefore, land cover changes in the Chelcheli protected area were mapped for 1991–2013 using time sequential Landsat TM and ETM at 30 meters resolution. Moreover, Maximum entropy (MaxEnt) modeling was used to investigate habitat selection of brown bear. The results showed that suitable patches overlapped with forest areas (Hyrcanian forest) and rivers. Our results also indicate that the brown bear habitat suitability is negatively influenced by human disturbance (e.g., roads, settlements). Increased human disturbance in brown bear habitat in recent decades may cause bears to avoid the disturbed areas. Therefore, the management plans should focus on reducing the human infrastructures around brown bear habitat. A suggestion is to place the core secure areas for brown bear inside the suitable habitat close to rivers where the human access is restricted. Promoting awareness of biodiversity conservation among tourism should also be one of the major focuses of management plans.
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