Near-shore areas face multiple stressors, effects of climate change, coastal construction and contamination. Although capping the seabed in these areas with mineral masses can reduce the impact of ...legacy contaminants in sediment, it can also result in the loss of flora and sessile fauna, both of which are vital components of near-shore ecosystems. Eelgrass (Zostera marina) is essential to marine near-shore areas as it supports biodiversity and mitigates the effects of climate change. Therefore, it would be beneficial to modify the top layer of caps to facilitate the reestablishment of these ecosystems when capping near-shore areas. This study describes results from an in situ, six-month field experiment conducted to compare increase in leaf length over the growing season and survival of eelgrass transplanted in two commercially available substrates (Natural sand and Crushed stone) and indigenous sediment (i.e., indigenous control sediment) in a capping project in Horten Inner harbour, Norway. Similar leaf length increase was found in Natural sand and Indigenous control sediment, both significantly higher compared to Crushed stone substrate. Survival was highest in our case in the Indigenous control sediment (120 %), with no significant difference between Crushed stone (20 %) and Natural sand substrates (25 %). These findings emphasize the importance of selecting appropriate substrate for successful seagrass restoration.
•Commercial substrates and indigenous sediment tested for seagrass reestablishment.•Lack of fine grains resulted in low survival of eelgrass in commercial substrate.•Eelgrass growth was low in substrate with chipped grains.•Growth and survival were best in indigenous substrate.
After becoming extinct approximately 250 years ago in the Palatinate Forest, the first Eurasian lynx (Lynx lynx) were reintroduced within this area in 2016, with 20 lynx reintroduced in the following ...five years. We observed the roe deer population within the Palatinate Forest before (2016) and during (2017–2019) the lynx reintroduction by estimating the population and evaluating the hunting bag. The roe deer population estimation based on the distance sampling method was conducted on ten defined transects with an average length of 48 km from 2016 to 2019, observing a 6,000 km transect length for 120 nights overall. An average of 6.54 ± 1.28 roe deer km-² was estimated over the course of the four years (2016 – 2019). Since we suspect that our estimations might underestimate the roe deer population within the Palatinate Forest, hence we preferred to use the roe deer count index for further analysis. Over the first four years (2016–2019), significant differences were neither found in the roe deer count index nor for the hunting bag in relation to the reintroduction of the lynx. The data and findings presented in this study provide a first insight into a long-term observation of a predator-prey system within the Palatinate Forest, with roe deer not having experienced a natural predator over a long time. In order to make coherent interpretations, long-term data is needed to estimate the population trends of both species within the Palatinate Forest.
▶ A rapid reduction in woodland and grassland cover occurred between 1972 and 2007. ▶ Increase in cultivated land and bushland cover also occurred in the same period. ▶ Frequent droughts, policy ...changes, and increase in dry years were the main drivers. ▶ The changes highly affected people's lifestyles.
This study uses a combination of remote sensing data, field observations and information from local people to analyze the patterns and dynamics of land-use/cover changes for 35 years from 1972 to 2007 in the arid and semi-arid Northern Afar rangelands, Ethiopia. A pixel-based supervised image classification was used to map land-use/cover classes. People's perceptions and ecological time-lines were used to explain the driving forces linked to the changes. A rapid reduction in woodland cover (97%) and grassland cover (88%) took place between 1972 and 2007. Bushland cover increased more than threefold, while the size of cultivated land increased more than eightfold. Bare land increased moderately, whereas bushy grassland and scrubland remained stable. According to accounts from local people, major events that largely explain the changes include: (1) severe droughts in 1973/74 and 1984/85; (2) increase in dry years during the last decade; and (3) immigration and increased sedentarization of pastoralists. If the present land-use/cover change were to continue, coupled with a drier climate, people's livelihoods will be highly affected and the pastoral production system will be under increasing threat.
Context
Within
Rangifer
ranges, many studies focus on expanding infrastructure and human activity negatively influencing habitat use. Little documentation exists on how disturbances act in synergy ...(i.e. cumulative effects), nor methods to test such effects.
Objectives
(1) Investigate how cumulative disturbance at different distances affects reindeer habitat use and (2) at what disturbance levels and distances loss of habitat functionality occurs.
Methods
Disturbance intensity levels for trails and infrastructure were based on expected amount of human activity, on a scale from 1 to 6. To test cumulative disturbance, we adapted the multi-grain method and summed-up disturbance intensity levels within “disturbance distance intervals” (0–0.25, 0.25–1, 1–2 km, etc. instead of 0–0.25, 0–1, 0–2 km, etc.), and tested reindeers’ avoidance using GPS data for 2011–2018.
Results
We found decreased habitat use within 0.25 km with increasing cumulative disturbance for snow free and winter seasons. For spring, a similar effect occurred up to 1 km. Reductions in use in areas with highest cumulative disturbance within these zones were between 92 and 98%. Strongest avoidance during spring supports previous studies. Comparatively, the multi-grain approach showed negative effects up to 3 km.
Conclusions
Our approach provides novel results and precisely estimates where cumulative effects actually occur. Reindeer in our study tolerate low intensities of human disturbance, while further increase in disturbance intensity reduces habitat functionality. We suggest clustering future human developments within areas of high disturbance, i.e. where functional habitat use is already lost or highly reduced. Our method can be used for other areas and species.
Anthropogenic activities affect habitat use by
Rangifer tarandus
, a particularly vulnerable species due to grouping behavior, extensive movements, and grazing ecology. We studied habitat use of ...GPS-collared reindeer in relation to surface mining activities during the snow-free season in Finnmark, Norway over a period of 7 years. Based on information about the mine’s level of operation (amount of people, vehicles, and equipment in operation) and rock blasting schedule, we divided data into high-activity periods (workdays) and low-activity periods (mine closed for ca 2.5 days on weekends and a yearly 3-week holiday period). We further divided workdays into periods with and without rock blasting and associated high-noise days. We found that reindeer significantly reduced habitat use at closer distances to the mine, indicating an influence zone up to 1.5 km. Reductions in use were strongest closest to the mine in high-activity periods. No avoidance effect of the mine was found beyond approximately 0.9 km for the 3-week holidays, 1.0 km for weekends, and 1.5 km for workdays with or without rock blasting. Compared to holidays and weekends, probability of use was reduced by 30–34% within 1.3 km from the mine for workday blasting periods, and up to 35% within 1.4 km for other workdays. Since averted areas can be partly utilized again within days or weeks following intensive mining activity periods, reduced mining activity in crucial periods for reindeer, such as during calving and migration, can be an effective mitigation measure.
Depending on the spatial scale, fluctuations in the area use of social, migratory herbivores may be related to changes in population size, season, predation, climatic variation, different types of ...disturbance, and random animal movement. We present a review and case study highlighting how study design limitations and publication bias have influenced our current knowledge on effects of human disturbance on
Rangifer
spp. Our case study illustrates how yearly variation may lead to false conclusions about the effects of infrastructure. From 58 analyses presented in 52 reviewed papers, we found that 14 analyses had study designs comparing area use before and after construction of infrastructure, 24 included spatial time series of > 6 years, 21 included spatiotemporal variation in their analyses, and only six contained both static and dynamic habitat variables. Categorizing the 58 analyses into 404 specific outcomes, we found that 64% of the authors focused their conclusions on negative effects and 14% focused on mixed effects but emphasized on negative effects of human activities and infrastructure, while only 53% of the outcomes actually showed negative effects, 34% no effects and 13% positive effects. Our review shows that only one study had a before–after-control–impact (BACI) design, and a majority of publications do not include before–after (BA) designs (76%), have not included spatiotemporal variation (64%), and do not evaluate the effects of spatial fluctuations on
Rangifer
area use at long enough time intervals (only 8 studies had > 10 years data). Although
Rangifer
is vulnerable to human disturbances, we have showed how the effects of infrastructure differ among studies and highlight the need for study designs that integrate and account for spatiotemporal variation in future studies, for a better understanding of
Rangifer
(or wildlife) area use in relation to anthropogenic effects.
We investigated barrier effects of a 66 kV power line established in 1966 before and after the line was upgraded to 132 kV in 2004 over a period of 44 years (1974-2017) in the North Ottadalen wild ...reindeer area (3245 km2) of which 1038 km2 are in use as winter pastures. The power line transects a peninsula (135 km2) with high quality winter pastures in the southeast periphery. The reindeer population originated from a nucleus herd of 402 animals of domestic origin released in the area in 1964-1965 and 100 resident wild animals. Yearly winter survey started in 1974 and reindeer were first surveyed south of the 66 kV power line in 1982. Comparing the number of animals recorded in the peninsula vs. the number of individuals expected relative to available grazing area during the three periods (1974-2004, 1982-2004 and 2005-2017), the number of animals recorded in the peninsula was 3.6–4.9 times higher than expected. Since the upgrade of the power line, a substantial part of the reindeer population grazed in the peninsula every year. We therefore conclude that there was no long-term barrier effect from the original power line and no barrier effects at all from the upgrade. However, during the first 5 surveys of this study, there were no animals in the peninsula. Therefore, even if there are several possible reasons for this, we cannot exclude the possibility of short-term barrier effects resulting from the construction of the original power line. Our results support recent studies that report no effects from existing power lines and contrast some previous findings that have reported strong long-term barrier and avoidance effects of such infrastructure for Rangifer migration and grazing behaviour.
Fire and overgrazing reduce aboveground biomass, leading to land degradation and potential impacts on soil organic carbon (SOC) and total nitrogen (TN) dynamics. However, empirical data are lacking ...on how prescribed burning and livestock exclusion impact SOC in the long-term. Here we analyse the effects of 19 years of prescribed annual burning and livestock exclusion on tree density, SOC and TN concentrations in the Sudanian savanna ecoregion at two sites (Tiogo and Laba) in Burkina Faso. Results revealed that neither livestock exclusion nor prescribed burning had significant impact on SOC and TN concentrations. The results at both sites indicate that 19 years of livestock and fire exclusion did not result in a significant increase in tree density compared to grazing and annual prescribed burning. The overall mean (± SEM) of SOC stocks in the 0–50 cm depth increment in the unburnt (53.5 ± 4.7 Mg C ha−1) and annually burnt (56.4 ± 4.3 Mg C ha−1) plots at Tiogo were not statistically different. Similarly, at Laba there was no significant difference between the corresponding figures in the unburnt (37.9 ± 2.6 Mg ha−1) and in the annually burnt plots (38.6 ± 1.9 Mg ha−1). Increases in belowground inputs from root turnover may have countered changes in aboveground biomass, resulting in no net change in SOC and TN. We conclude that, contrary to our expectation and current policy recommendations, restricting burning or grazing did not result in increase in SOC stocks in this dry savanna ecosystem.
Shade coffee farming has been promoted as a means of combining sustainable coffee production and biodiversity conservation. Supporting this idea, similar levels of diversity and abundance of birds ...have been found in shade coffee and natural forests. However, diversity and abundance are not always good indicators of habitat quality because there may be a lag before population effects are observed following habitat conversion. Therefore, other indicators of habitat quality should be tested. In this paper, we investigate the use of two biomarkers: fluctuating asymmetry (FA) of tarsus length and rectrix mass, and feather growth bars (average growth bar width) to characterize the habitat quality of shade coffee and natural forests. We predicted higher FA and narrower feather growth bars in shade coffee forest versus natural forest, indicating higher quality in the latter. We measured and compared FA in tarsus length and rectrix mass and average growth bar width in more than 200 individuals of five bird species. The extent of FA in both tarsus length and rectrix mass was not different between the two forest types in any of the five species. Similarly, we found no difference in feather growth between shade coffee and natural forests for any species. Therefore, we conclude our comparison of biomarkers suggests that shade coffee farms and natural forests provide similar habitat quality for the five species we examined.
Wildlife-vehicle collision (WVC) is one of the major causes of wildlife mortality and a concern for conservationists worldwide. The study of roadkill data that can be used to develop appropriate ...measures and strategies for both wildlife conservation and traffic safety to mitigate the WVC and animals' mortality. Extensive studies have been conducted in the developed countries on the identification of WVC hotspots and its potential impact; however, less attention is given in developing countries. Because of this, the problem is not well understood in developing countries. This study was intended to identify victim species, hotspot areas for roadkill, and factors that contribute to WVC in Jimma Zone, along three roads leading from Jimma City. Data were collected using a citizen science approach and a skilled man power road survey (March–September 2022) to document the number and type of species killed. Three road segments (135 km in total) were surveyed weekly as a baseline for future research. All statistical analyses were carried out using R-software. In the present study, a total of 84 roadkill specimens were collected from 16 different mammal species, of which 85.7% were medium-sized carnivores. The findings showed that Jackals (Canis mesomalis and Canis adustus) were the most frequently killed species (25%, n is 21), followed by Civettictis civetta (22.62%, n is 19). The study revealed that the major factors causing collisions include habitat type (forest cover) and wildlife behavior (nocturnal or diurnal). Further, the study revealed that the majority of WVC occurred at night (dusk) and at dawn in areas that are covered with dense forests. To minimize the potential risks of WVC and animals’ mortality, we suggest putting warning signs in hotspot areas where roadkill usually occur frequently. In addition, we recommend creating awareness among drivers, traffic police, and all communities about the negative impacts and consequences of collisions on the ecological and economic value of wildlife.
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