Monitoring of small rock pools reveals differential effects of chronic anthropogenic disturbance on birds and mammals in the Calakmul region, southern Mexico

2021 ◽  
pp. 1-10
Author(s):  
Carlos M. Delgado-Martínez ◽  
Fredy Alvarado ◽  
Melanie Kolb ◽  
Eduardo Mendoza

Abstract Great attention has been drawn to the impacts of habitat deforestation and fragmentation on wildlife species richness. In contrast, much less attention has been paid to assessing the impacts of chronic anthropogenic disturbance on wildlife species composition and behaviour. We focused on natural small rock pools (sartenejas), which concentrate vertebrate activity due to habitat’s water limitation, to assess the impact of chronic anthropogenic disturbance on the species richness, diversity, composition, and behaviour of medium and large-sized birds and mammals in the highly biodiverse forests of Calakmul, southern Mexico. Camera trapping records of fauna using sartenejas within and outside the Calakmul Biosphere Reserve (CBR) showed that there were no effects on species richness, but contrasts emerged when comparing species diversity, composition, and behaviour. These effects differed between birds and mammals and between species: (1) bird diversity was greater outside the CBR, but mammal diversity was greater within and (2) the daily activity patterns of birds differed slightly within and outside the CBR but strongly contrasted in mammals. Our study highlights that even in areas supporting extensive forest cover, small-scale chronic anthropogenic disturbances can have pervasive negative effects on wildlife and that these effects contrast between animal groups.

2021 ◽  
Vol 13 (5) ◽  
pp. 18177-18188
Author(s):  
Amit Kumar ◽  
Yogesh Dubey ◽  
Advait Edgaonkar

With increasing fragmentation of natural areas and a dramatic reduction of forest cover in several parts of the world, quantifying the impact of such changes on species richness and community dynamics has been a subject of much concern.  Therefore, this study intends to assess avifaunal biodiversity in fragmented forests.  Forest patches between the sizes of 10ha and 700ha were identified in Bhopal Forest Circle (BFC), which covers the Vindhyan plateau.  Forest patches were classified based on their size and degree of isolation.  A sample of 21 forest fragments was selected using proportional sampling.  Bird surveys were conducted using the point count method at each site.  Three replicates were taken at each site.  Avian species richness of each patch was calculated.  The results suggest that species richness is positively associated with the size of the forest patches.  Larger forest patches such as Binapur (166ha, Chao 1= 73), Sayar (107ha, Chao 1= 78) and Kalyanpura (133ha, Chao 1= 80) had relatively high species richness, except for patches including Narsinghgarh (393ha, Chao 1= 28) and Singota (184ha, Chao 1= 45) with high levels of anthropogenic disturbance.  Smaller forest patches were found to have fewer bird species, although small forest patches with lesser degrees of anthropogenic disturbance such as Lalghati (99ha, Chao 1 = 62), Lasudli (16ha, Chao 1 = 65), Ghot (36ha, Chao 1 = 53), and Nasipur (23ha, Chao 1 =52) were more diverse than other patches.  These patches were more protected due to being sacred groves (Lalghati and Lasudli) or under private ownership (Ghot and Nasipur).  A total of 131 bird species were recorded from all the sampled forest patches.  These results suggest that forest patches embedded in an agrarian landscape play a vital role in conserving biodiversity, hence conservation efforts should also be focused on these forest fragments.


SURG Journal ◽  
2017 ◽  
Vol 9 (1) ◽  
pp. 5-13
Author(s):  
Adrian Helmers ◽  
Alexis Platek ◽  
Melissa Ponte ◽  
Natalie Secen ◽  
Karl Cottenie

This study quantified the impact of human activity on aquatic and shoreline plant species richness. We hypothesized that human activity at the shoreline would negatively impact plant species richness and that the extent of the impact would depend on the intensity of human activity. To test this, we sampled 11 lakes in Algonquin Provincial Park, of which five permitted motorboat access, and five permitted canoe access and prohibited motorboat access. The remaining lake, which had no designated access point for boats and was only accessible to researchers, acted as a control. To assess the impact of anthropogenic disturbance at each lake, we measured plant species richness in three 10 m by 2 m plots: a first plot at the access point, assumed to be the site of highest disturbance; a second at the site of intermediate disturbance, 30 m down shore from the access point; and a third at the site of lowest disturbance, 60 m down shore from the access point. We found a significant negative relationship between the level of disturbance and plant species richness, both in the motorboat-accessible and canoe access-only lakes. The control lake exhibited no correlation between disturbance level and plant species richness. However, there was no significant difference between motorboat-accessible and canoe access-only lakes in the relationship between disturbance level and plant species richness. Overall, this study highlights the consequences of anthropogenic disturbance on freshwater aquatic and shoreline plant communities, and provides a framework for future management and rehabilitation strategies.


2018 ◽  
Vol 76 (1) ◽  
pp. 153-164 ◽  
Author(s):  
José Amorim Reis-Filho ◽  
Euan S Harvey ◽  
Tommaso Giarrizzo

Abstract The data requirements and resources needed to develop effective indicators of fishing impacts on target stocks may often be great, especially for mangrove fisheries where, for example, tidal cycles sequentially flood and drain the habitat as a result of natural processes. Here, we used underwater video systems to evaluate the impact of small-scale fisheries on mangrove fish assemblages at four levels of fishing pressure (low, medium, high, and no pressure). The lowest values of species richness and abundance were recorded in the areas fished most intensively. Conversely, the highest species richness and the occurrence of larger-bodied fish were recorded in areas of reduced fishing activity, which was surprisingly similar to the “no fishing” areas. The slopes of the community size spectra steepened in response to exploitation, while the relative abundance of medium-sized fish (16–25 cm) declined. Fishing for local or regional markets, rather than subsistence, also led to a decrease in the abundance of larger fish (>41 cm). The marked response of population parameters to fishing pressure reflected the impact of unregulated small-scale fisheries on areas of mangroves. Fishery management practices that ignore contemporary changes in these environments are likely to overestimate long-term yields, leading to overfishing. Thus, size-based approaches to evaluating fishing pressure were suitable for detecting negative responses from the mangrove fish assemblages. A next step will be to integrate size- and species-based ecological approaches that provide mechanisms to address pronounced decreases in specific species as a more profitable indicator of fishing impacts on mangrove fish assemblages. This approach will allow the development of effective conservation and management strategies.


PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3914
Author(s):  
Helen R.P. Phillips ◽  
Sandra Knapp ◽  
Andy Purvis

Background With the increase in human population, and the growing realisation of the importance of urban biodiversity for human wellbeing, the ability to predict biodiversity loss or gain as a result of land use change within urban settings is important. Most models that link biodiversity and land use are at too coarse a scale for informing decisions, especially those related to planning applications. Using the grounds of the Natural History Museum, London, we show how methods used in global models can be applied to smaller spatial scales to inform urban planning. Methods Data were extracted from relevant primary literature where species richness had been recorded in more than one habitat type within an urban setting. As within-sample species richness will increase with habitat area, species richness estimates were also converted to species density using theory based on the species–area relationship. Mixed-effects models were used to model the impact on species richness and species density of different habitat types, and to estimate these metrics in the current grounds and under proposed plans for redevelopment. We compared effects of three assumptions on how within-sample diversity scales with habitat area as a sensitivity analysis. A pre-existing database recording plants within the grounds was also used to estimate changes in species composition across different habitats. Results Analysis estimated that the proposed plans would result in an increase of average biodiversity of between 11.2% (when species density was modelled) and 14.1% (when within-sample species richness was modelled). Plant community composition was relatively similar between the habitats currently within the grounds. Discussion The proposed plans for change in the NHM grounds are estimated to result in a net gain in average biodiversity, through increased number and extent of high-diversity habitats. In future, our method could be improved by incorporating purposefully collected ecological survey data (if resources permit) and by expanding the data sufficiently to allow modelling of the temporal dynamics of biodiversity change after habitat disturbance and creation. Even in its current form, the method produces transparent quantitative estimates, grounded in ecological data and theory, which can be used to inform relatively small scale planning decisions.


2005 ◽  
Vol 32 (1) ◽  
pp. 30-41 ◽  
Author(s):  
FRANCISCA C. AGUIAR ◽  
MARIA TERESA FERREIRA

Human activities within fluvial corridors and surrounding landscapes have persistently stressed riparian ecosystems, particularly in Iberian Mediterranean-type streams. The impact of human disturbance relative to natural environmental factors in shaping riparian vegetation is still poorly understood. Both regional variables (such as altitude and precipitation), and site-specific characteristics (such as substrate and riverbank modifications) were analysed as potential determinants of riparian vegetation patterning to determine the relative influences of the diverse land-use types and environmental factors on the composition (including floristic species richness and percentage cover of trees, shrubs and woody climbers) and integrity (width of riparian woods and patterns of longitudinal continuity) of riparian woods in eight river basins of the Tagus fluvial system (Portugal). There was patchy establishment of riparian woods, with generally low average width and low species richness, as well as significant inter-basin differences and upstream-downstream variations in riparian features. Species distribution was clearly determined by environmental factors, such as human disturbance on the riverbanks and geological background, and the environmental variables and the land use in the river valley partially explained the integrity of riparian woody vegetation. The results highlight the predictive capability of reach-level features; it appears that, linked with the geomorphological and climate context, small-scale human disturbances on riparian corridors play a major role in explaining the remaining biological variability.


2017 ◽  
Author(s):  
Claudia L. Gray ◽  
Eleanor M. Slade ◽  
Darren J. Mann ◽  
Owen T. Lewis

ABSTRACTOil palm expansion threatens biodiverse ecosystems across the tropics. However, palm oil is a widely used and profitable crop, so identifying strategies that mitigate the impact of oil palm expansion on biodiversity is important. Riparian reserves (strips of forest along rivers) are protected in many countries for hydrological reasons and also support species that would not otherwise persist in oil palm. However, management guidelines for riparian zones have been informed by relatively few ecological studies. We assessed how the structural features and landscape context of riparian reserves in Sabah, Malaysia affected dung beetle communities. We also tested the use of flight intercept traps to study movement of dung beetles along linear forest corridors. Overall, dung beetle abundance in riparian reserves was 54% lower than in logged forest areas, but all species observed in the logged forest were found in at least one riparian reserve site and both species richness and diversity increased with reserve width. Distance from a large block of continuous forest affected dung beetle community composition but not species richness, abundance, or functional diversity. The amount of forest cover in the surrounding landscape improved the retention of species within riparian reserves, and increases in vegetation complexity corresponded with higher functional richness and functional dispersion. The flight intercept traps did not indicate that there is net movement of individuals out of logged forest areas into the riparian reserves. The species richness of 30 m reserves (the suggested requirement of reserves in Sabah) was only 10% lower than in logged forest, but our data indicate that riparian reserves of at least 50 – 80 m are needed for species richness and diversity to equal that in nearby logged forest. These findings, particularly if they apply more widely to forest-dependent taxa, should be taken into account when setting policy and sustainability guidelines for oil palm plantations, both in areas undergoing conversion from forest and in existing oil palm plantations where forest restoration is required.


2021 ◽  
Vol 263 ◽  
pp. 109338
Author(s):  
Carmen Galán-Acedo ◽  
Denise Spaan ◽  
Júlio César Bicca-Marques ◽  
Renata Bocorny de Azevedo ◽  
Fabricio Villalobos ◽  
...  

2021 ◽  
Vol 13 (18) ◽  
pp. 3762
Author(s):  
Xavier Haro-Carrión ◽  
Jon Johnston ◽  
Maria Juliana Bedoya-Durán

Despite high fragmentation and deforestation, little is known about wildlife species richness and occurrence probabilities in tropical dry forest (TDF) landscapes. To fill this gap in knowledge, we used a Sentinel-2-derived land-cover map, Normalized Difference Vegetation Index (NDVI) data and a multi-species occupancy model to correct for detectability to assess the effect of landscape characteristics on medium and large mammal occurrence and richness in three TDF areas that differ in disturbance and seasonality in Ecuador. We recorded 15 species of medium and large mammals, distributed in 12 families; 1 species is critically Endangered, and 2 are Near-Threatened. The results indicate that species occupancy is related to low forest cover and high vegetation seasonality (i.e., high difference in NDVI between the wet and dry seasons). We believe that the apparent negative effect of forest cover is an indicator of species tolerance for disturbance. The three sampling areas varied from 98% to 40% forest cover, yet species richness and occupancy were not significantly different among them. Vegetation seasonality indicates that more seasonal forests (i.e., those where most tree species lose their leaves during the dry season) tend to have higher mammal species occupancy compared to less seasonal, semi-deciduous forests. Overall, occupancy did not vary between the dry and wet seasons, but species-specific data indicate that some species exhibit higher occupancy during the wet season. This research offers a good understanding of mammal species’ responses to habitat disturbance and fragmentation in TDFs and provides insights to promote their conservation.


Therya ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 237-248
Author(s):  
Jesús Alejandro Ríos-Solís ◽  
José Juan Flores-Martínez ◽  
Víctor Sánchez-Cordero ◽  
Mario C. Lavariega

Studies on diversity of animal communities allow determination of their species richness and composition.  This information is particularly relevant to establish sound conservation programs in biosphere reserves, where human activities should be focused on the sustainable use of natural resources and ensure biodiversity protection.  This study estimated the diversity and species richness and determined the species composition and activity patterns of medium- and large-sized terrestrial mammals in the Los Tuxtlas Biosphere Reserve (LTBR) located in Veracruz, Mexico.  We set 18 camera traps to record medium and large-sized terrestrial mammals from August 2016 to January 2017.  We calculated the trapping rate, guilds, and activity patterns of species.  Diversity was estimated with Hill numbers.  We compared our estimates with other studies in tropical forest in Mexico.  We obtained 308 independent captures of 13 species; Cuniculus paca and Dasyprocta mexicana were the species with the highest trapping rate.  Order-0, order-1, and order-2 diversity values were 13.99, 6.50, and 4.75 effective species, respectively, which ranks LTBR the fourth-most diverse reserve of medium- and large-sized terrestrial mammals compared to six other tropical rainforest sites in southern Mexico.  We recorded mammals representing five trophic guilds, of which frugivore-folivores (five species) and omnivores (three species) ranked highest.  All recorded species were primarily nocturnal (six species) or diurnal (six species).  Tamandua mexicana, Leopardus pardalis, L. wiedii, and Eira barbara are listed as endangered in the Mexican Official Standard Norm NOM-059-2019, and L. wiedii is listed as near threatened in the IUCN Red List of Threatened Species.  We were able to record 40.6 % of the terrestrial mammal species known to inhabit the LTBR.  The absence of large-sized species such as large predators and herbivores was notable.  Comparison of medium and large-sized mammal diversity of camera trapping studies in Mexico show that landscape degradation is impoverishing terrestrial mammal communities.


2019 ◽  
Vol 11 (7) ◽  
pp. 13850-13867 ◽  
Author(s):  
Mattias Van Opstal ◽  
Bernard Oosterlynck ◽  
Million Belay ◽  
Jesse Erens ◽  
Matthias De Beenhouwer

The Sheka Zone in southwestern Ethiopia is covered by some of the largest remaining forests in the Eastern Afromontane biodiversity hotspot.  Owing to the rich biodiversity and a high degree of endemism, it was declared as a biosphere reserve by UNESCO in 2012 and is considered a Key Biodiversity Area.  Detailed knowledge on species diversity and distribution in the reserve is, however, severely limited.  From February to April 2016, an assessment of the bird diversity and distribution in the reserve was made for the first time through point count transects, camera-trap recordings and opportunistic observations.  In total, 244 bird species were identified, of which 19% was only found within the reserve’s designated protected zones.  Our study indicates a remarkable bird species richness across the different habitats in Sheka Forest Biosphere Reserve and can be used as a baseline for future monitoring studies and conservation planning.  


Sign in / Sign up

Export Citation Format

Share Document