Anthropogenic Habitat Degradation Research Articles

Genetic rescue often leads to higher fitness as a result of increased heterozygosity across animal taxa.

Biodiversity loss has reached critical levels partly due to anthropogenic habitat loss and degradation. These landscape changes are damaging as they can fragment species distributions into small, isolated populations, resulting in limited gene flow, population declines and reduced adaptive potential. Genetic rescue, the translocation of individuals to increase genetic diversity and ultimately fitness, has produced promising results for fragmented populations but remains underutilized due to a lack of long-term data and monitoring. To promote a better understanding of genetic rescue and its potential risks and benefits over the short-term, we reviewed and analysed published genetic rescue attempts to identify whether genetic diversity increases following translocation, and if this change is associated with increased fitness. Our review identified 19 studies that provided genetic and fitness data from before and after the translocation; the majority of these were on mammals, and included experimental, natural and conservation-motivated translocations. Using a Bayesian meta-analytical approach, we found that on average, genetic diversity and fitness increased in populations post translocations, although there were some exceptions to this trend. Overall, genetic diversity was a positive predictor of population fitness, and in some cases this relationship extended three generations post-rescue. These data suggest a single translocation can have lasting fitness benefits, and support translocation as another tool to facilitate conservation success. Given the limited number of studies with long-term data, we echo the need for genetic monitoring of populations post-translocation to understand whether genetic rescue can also limit the loss of adaptive potential in the long-term.

Beta diversity partitioning reveals homogenization in bird community composition within the forest-agriculture landscape of the northern Taiwan coast

ContextThis study examined how human-induced landscape changes affected bird diversity in mountain villages with mixed forests and cultivated fields.ObjectivesWe focused on the bird species composition (beta diversity) to determine whether species homogenization varied with forest cover differences. This study developed it as a novel metric potentially quantifying homogenization level comparison in species functional groups.MethodsBird surveys were conducted at 27 sites with forest cover scattered from 0 to 100%. Bird species were divided into forest birds and nonforest birds. Beta diversity was partitioned into turnover and nestedness-resultant components, and their contribution ratio to Sørensen beta was used to examine the effect of forest cover and pairwise cover difference.ResultsOur results indicated that forest birds exhibited low turnover and low nestedness, whereas nonforest birds exhibited nestedness distribution characteristics. The nestedness-resultant contribution ratio of nonforest birds was higher, driven by forest cover difference (slope = 0.0080, Pseudo R2 = 0.35**) than that of forest birds (slope = 0.0018, Pseudo R2 = 0.02**). Thus, we quantify the result of forest cover decreased lead to the dominated by nestedness species in nonforest birds.ConclusionsThese findings highlight the distinct effects of environmental changes on these two bird functional groups. Although the Sørensen beta diversity increases with forest cover decrease, most are contributed by nestedness-resultant nonforest birds and lead to homogenization. Thus, it is recommended that conservation plans should separately address forest and nonforest bird species to avoid the risk of underestimating species homogenization due to anthropogenic land-use and habitat degradation.

Microgeographic variation in demography and thermal regimes stabilize regional abundance of a widespread freshwater fish.

Predicting the persistence of species under climate change is an increasingly important objective in ecological research and management. However, biotic and abiotic heterogeneity can drive asynchrony in population responses at small spatial scales, complicating species-level assessments. For widely distributed species consisting of many fragmented populations, such as brook trout (Salvelinus fontinalis), understanding the drivers of asynchrony in population dynamics can improve the predictions of range-wide climate impacts. We analyzed the demographic time series from mark-recapture surveys of 11 natural brook trout populations in eastern Canada over 13 years to examine the extent, drivers, and consequences of fine-scale population variation. The focal populations were genetically differentiated, occupied a small area (~25 km2 ) with few human impacts, and experienced similar climate conditions. Recruitment was highly asynchronous, weakly related to climate variables and showed population-specific relationships with other demographic processes, generating diverse population dynamics. In contrast, individual growth was mostly synchronized among populations and driven by a shared positive relationship with stream temperature. Outputs from population-specific models were unrelated to four of the five hypothesized drivers (recruitment, growth, reproductive success, phylogenetic distance), but variation in groundwater inputs strongly influenced stream temperature regimes and stock-recruitment relationships. Finally, population asynchrony generated a portfolio effect that stabilized regional species abundance. Our results demonstrated that population demographics and habitat diversity at microgeographic scales can play a significant role in moderating species responses to climate change. Moreover, we suggest that the absence of human activities within study streams preserved natural habitat variation and contributed to asynchrony in brook trout abundance, while the small study area eased monitoring and increased the likelihood of detecting asynchrony. Therefore, anthropogenic habitat degradation, landscape context, and spatial scale must be considered when developing management strategies to monitor and maintain populations that are diverse, stable, and resilient to climate change.

Factors associated with Paddlefish (Polyodon spathula) restoration success in Oklahoma

AbstractThe Paddlefish (Polyodon spathula) has been extirpated from portions of its native range due to anthropogenic habitat degradation and fragmentation, most notably the impoundment of rivers. To mitigate some of these losses in Oklahoma, Paddlefish have been stocked into reservoirs throughout the state, with variable success in establishing self‐sustaining populations. Two factors thought to contribute to success of Paddlefish stocking are spawning substrate and prey availability, which were quantified in six reservoirs and nine reservoir tributaries. Side‐scan sonar and supervised classification of aerial imagery were used to classify 4517‐ha of river substrate upstream of the river‐reservoir interface in reservoir tributaries. Zooplankton community structure, water clarity, and nutrient availability were also assessed in the same reservoirs and tributaries. One tributary had suitable spawning substrate (>40%), and the rest had minimal (<1.5%), which suggested that availability of suitable spawning substrate was not directly correlated with Paddlefish stocking success. Reservoirs with self‐sustaining Paddlefish populations had higher abundance of large zooplankton (copepods and cladocerans) than reservoirs without a reproducing population. Notably, tributaries associated with Lake Texoma, the one known example of failed restoration, were much more turbid than other rivers. We conclude that abiotic factors such as water clarity may contribute more to variable recruitment than spawning substrate or zooplankton abundance by mediating foraging success of Paddlefish post‐larvae.

Assessment of reptile response to habitat degradation in arid and semi-arid regions

Reptiles are essential components of global biodiversity and dynamic ecosystems due to their ecological roles and functions. However, they face significant vulnerability to anthropogenic disturbances and habitat degradation, resulting in their classification as the third most threatened vertebrate group globally. The current study examines reptile response to anthropogenic habitat degradation in the highly biodiverse Souss-Massa National Park (SMNP), located on the North African Atlantic coast. During 2021 and 2022, linear transects were established within four habitat categories experiencing varying degrees of vegetation cover degradation (undegraded, slightly degraded, moderately degraded, and highly degraded), caused by livestock overgrazing and vegetation clearance. Based on the comparisons of the Normalized Difference Vegetation Index means, the vegetation cover differed significantly among the selected habitat categories, with a noticeable reduction in the natural vegetation cover as the level of habitat degradation increased. The visual encounter survey technique was used to search a total of 96 transects, with each of the studied habitat categories being represented by 24 transects. Species richness, diversity, abundance, composition and similarities of reptile communities were determined and compared between habitat categories. During the study period, 11 species (438 individuals) were encountered, accounting for 48 % of SMNP reptile fauna. Species richness, diversity and abundance differed significantly among habitat categories, with the lowest means recorded in the highly degraded areas. Reptiles responded differently to habitat degradation based on their taxonomic levels, thus indicating a species-specific impact of degradation. Species composition varied considerably among habitat categories, with highly degraded areas displaying significant differences and the lowest degree of similarity when compared to all other categories (p = 0.0006). Anthropogenic alterations in reptile abundance distribution and species occurrence likely account for the observed differences in species composition within the different habitat categories. The reported reptile responses to habitat degradation might be attributed to factors associated with natural vegetation, such as food availability, microhabitat preferences, or interactions with other species. Exploring these factors in future research could provide further insights into the mechanisms driving reptile community responses to habitat degradation. Such data can provide valuable information for implementing effective conservation measures to prevent anthropogenic habitat degradation and protect threatened species in arid and semi-arid areas.

Assessing the effectiveness of Ecological Conservation Red Line for mitigating anthropogenic habitat degradation in river corridors

The ecological conservation red line (ECRL) framework plays an increasingly important role in biodiversity conservation practices in China. Following the implementation of ECRL, it is essential to systematically assess the effectiveness of this national policy in mitigating the negative impacts of human disturbances on habitat quality at the landscape and regional levels. Combined with remote sensing and ground survey data, the Integrated Valuation of Ecosystem Services and Trade-off (InVEST) habitat quality model was used to evaluate the impact of six major anthropogenic activities, including built-up land, roads, mining land, crop land, water pollution, and grazing, on habitat degradation in two grassland river corridors (Kherlen River corridor and Wuerxun River corridor) in Northeastern China. Then, the effectiveness of different management scenarios was assessed based on the ECRL framework. The results indicated that over 80% of the habitat degradation was attributed to grazing activities, followed by water pollution. Built-up land, roads, mining land, and crop land played minor roles in causing habitat degradation. Comparing the implementation of ECRL management scenario with no ECRL management scenario, habitat degradation in the Kherlen River corridor reduced by 17.86%, and habitat quality improved by 11.11%. Similarly, in the Wuerxun River corridor, compared with the priority ECRL management scenario, habitat degradation reduced by 69.23%, and habitat quality improved by 2.38% in the implementation of ECRL management scenario. Moreover, an optimized ECRL management scenario, including grazing prohibition, grassland enclosure, and ecological restoration of river habitats, further improved the habitat quality of both river corridors, resulting in a 12.70% improvement for the Kherlen River corridor and a 3.57% improvement for the Wuerxun River corridor. Our work provides a quantitative framework for optimizing conservation and restoration measures for river corridors based on the ECRL.

Do habitat fragmentation and degradation influence the strength of fine-scale spatial genetic structure in plants? A global meta-analysis.

As primarily sessile organisms, plants often show a non-random spatial distribution of genotypes over distance. This process known as fine-scale spatial genetic structure (FSGS) has been suggested through systematic reviews to depend on life form, mating system, and pollen and seed dispersal vectors, while there is no consensus on its behaviour due to external factors, such as anthropogenic habitat changes. By conducting a systematic review and global meta-analysis of empirical FSGS studies, we aimed to evaluate how anthropogenic habitat fragmentation and degradation influence the strength of FSGS in plant populations by means of the Sp statistic. Moreover, we tested how pollination and seed dispersal vectors contribute to the variation of the Sp statistic. We retrieved 243 FSGS studies from 1960 to 2020 of which only 65 were informative for the systematic review. Most empirical studies comprised outcrossers (84%) and trees (67%), with few herbs (23%) and scarce annual species (2%). In weighted meta-analyses for 116 plant populations (31 studies), we did not detect significant effects in the magnitude of effect sizes for the Sp statistic among undisturbed, degraded and fragmented habitats. Results showed significant effects for seed dispersal vectors, but not for pollination. Overall, we observed high variation among the effect sizes (not related to the goodness-of-fit of mixed models) of habitat status, pollination and seed dispersal categories, which precludes identifying biological trends on the Sp statistic. More empirical studies are needed that contrast multiple plant populations in disturbed versus undisturbed habitats, and by increasing the taxonomic groups, such as herbs and annual plants.

Vulnerability to climate change of managed stocks in the California Current large marine ecosystem

IntroductionUnderstanding how abundance, productivity and distribution of individual species may respond to climate change is a critical first step towards anticipating alterations in marine ecosystem structure and function, as well as developing strategies to adapt to the full range of potential changes.MethodsThis study applies the NOAA (National Oceanic and Atmospheric Administration) Fisheries Climate Vulnerability Assessment method to 64 federally-managed species in the California Current Large Marine Ecosystem to assess their vulnerability to climate change, where vulnerability is a function of a species’ exposure to environmental change and its biological sensitivity to a set of environmental conditions, which includes components of its resiliency and adaptive capacity to respond to these new conditions.ResultsOverall, two-thirds of the species were judged to have Moderate or greater vulnerability to climate change, and only one species was anticipated to have a positive response. Species classified as Highly or Very Highly vulnerable share one or more characteristics including: 1) having complex life histories that utilize a wide range of freshwater and marine habitats; 2) having habitat specialization, particularly for areas that are likely to experience increased hypoxia; 3) having long lifespans and low population growth rates; and/or 4) being of high commercial value combined with impacts from non-climate stressors such as anthropogenic habitat degradation. Species with Low or Moderate vulnerability are either habitat generalists, occupy deep-water habitats or are highly mobile and likely to shift their ranges.DiscussionAs climate-related changes intensify, this work provides key information for both scientists and managers as they address the long-term sustainability of fisheries in the region. This information can inform near-term advice for prioritizing species-level data collection and research on climate impacts, help managers to determine when and where a precautionary approach might be warranted, in harvest or other management decisions, and help identify habitats or life history stages that might be especially effective to protect or restore.

Anthropogenic threats and habitat degradation challenge the conservation of palm genetic resources—an appraisal of current status, threats and look-ahead strategies

Anthropogenic threats and habitat degradation challenge the conservation of palm genetic resources—an appraisal of current status, threats and look-ahead strategies

Effect of plant composition on epigeal spider communities in northern New Zealand forest remnants

Te Paki Ecological District (TPED) in northern Northland, New Zealand, is well known as an ecologically significant centre of endemism. However, due to extensive anthropogenic habitat degradation, native forest has been reduced to small, isolated remnants and many of its endemic species are threatened with extinction. Epigeal spider communities (species living on or near the ground) were surveyed within TPED by pitfall trapping at seven native forest remnants differing in plant composition and apparent seral stage to investigate how spider communities varied within them.

Life in This World and For the Life of the World: Natural Science and the Social Ethos of the Orthodox Church

For the Life of the World: Toward a Social Ethos of the Orthodox Church (FLOW) is an admirable and important document, not least because it affirms natural scientific insights as valuable resources for Christian theology and social teaching. Given the current Ecumenical Patriarch's extensive engagement with environmental concerns, this affirmation is especially apposite. However, I do not believe FLOW fully recognizes the implications of such insights for its conception of God's creation or its social ethos. In particular, FLOW maintains that scarcity, competition, violence, and death are distortions of God's creation due to human sin and that human beings are commissioned and capacitated by God to strive to overcome them. By contrast, I contend that contemporary scientific understandings of planetary forces and ecological processes—and indeed Christian scripture—give Christians cause to consider scarcity, competition, violence, and death aspects of God's creation. I further claim that striving to overcome scarcity, competition, violence, and death would be environmentally disastrous and spiritually deleterious since it would domesticate the rapidly disappearing wilderness that biblical wisdom literature depicts as delighting and glorifying God. Happily, allowing natural scientific insights to inform Orthodox conceptions of God's creation in this way would render FLOW's injunction that human beings redress the environmental implications of their sin an imperative to reduce and remedy pollution and to minimize and restore anthropogenic habitat degradation and destruction, thereby fostering the ecological sustainability Orthodoxy champions and the respect for wilderness Christians have multiple reasons to commend. Although this abandons FLOW's aspiration that human beings wholly civilize God's creation, such respect for wilderness does not imply acquiescence to human deprivation and distress, for just as it is inappropriate to impose cultural values on all of nature, it is wrong to regard all natural dynamics culturally normative. Similarly, attributing scarcity, competition, violence, and death to God's creation rather than its sin need not undermine Christian hopes for freedom from these and all other maladies, for Christians await not only God's salvation from sin and its effects but God's new creation too. Thus, in addition to honing Orthodoxy's social ethos, heeding FLOW's embrace of natural scientific insights as constructive theological resources foregrounds a commonly neglected dimension of Christians' traditional depiction of the divine economy.

New microsatellite markers for Ellipse, Venustaconcha ellipsiformis (Bivalvia: Unionidae), with notes on optimal sample size and cross-species amplification

Venustaconcha ellipsiformis (Unionidae) is a freshwater mussel species inhabiting small to medium streams of the Midwestern United States; however, its occurrence is rather sporadic and populations are often isolated. Due to anthropogenic habitat degradation and water pollution, this species is designated as some sort of conservation status in many states. To prioritize conservation strategies, highly variable genetic markers are necessary to assess population genetic structure and potential genetic erosion of V. ellipsiformis. Using whole genome sequence data, we developed and characterized microsatellite markers for V. ellipsiformis. Among 23 tetranucleotide loci tested, 14 loci were consistently amplified and showed polymorphism. Analyses performed on three populations in the upper Mississippi River basin showed that the number of alleles per locus ranged from 2 to 11 and the observed heterozygosity varied from 0.15 to 0.75. Based on genotypic and allelic rarefaction curves, these loci had adequate statistical power to genetically discriminate between individuals and the sample size was large enough to capture most alleles available in the populations at most loci. Finally, cross-species screening of the loci successfully amplified and showed polymorphism in six species in the tribe Lampsilini. The microsatellite loci developed in this study provide a valuable addition to extant genetic markers for freshwater mussels and can be useful to provide high-level resolution of population genetic parameters for V. ellipsiformis. Such information will be of great value for resource managers developing and prioritizing conservation strategies for imperiled mussel species.

Activity budget, home range and diet of the Colombian night monkey (Aotus lemurinus) in peri-urban forest fragments.

Forest fragmentation and deforestation are major threats to primates at a global scale. The survival of primates in forest fragments largely depends on their behavioral and dietary flexibility, as well as their ability to use a modified matrix in anthropogenic landscapes, hence the importance of determining these ecological parameters in habitats with strong anthropic interventions. This paper aims to describe the activity budget and diet of two groups of the Colombian night monkey (Aotus lemurinus) and to estimate their home range in two peri-urban forest fragments in the city of Manizales, Colombia. We combined scan sampling and handheld GPS fixes in order to determine the behavioral, dietary and spatial patterns of the study groups. Night monkeys spent most of their time resting and traveling and were mainly frugivorous relying on at least 26 plant species in their diet. The most consumed plants included Persea americana, Cecropia angustifolia, Musa x paradisiaca, Cecropia telenitida, and Croton cf. mutisianus. Two of these plants are cultivated species and can provide important resources for populations in small forest fragments. Home range sizes were estimated at 1.7 to 1.8 hectares, using a grid count method. Our results suggest the potential adaptability that these primates have when exposed to anthropogenic habitat disturbances and habitat degradation. Nonetheless, future studies should evaluate the influence of demographic factors and resource availability on the behavioral, dietary and spatial patterns of A. lemurinus in peri-urban forests, in order to further understand their ability to cope with the pervasive processes of habitat fragmentation in the northern Andes.

Basin-wide infaunalisation of benthic soft-bottom communities driven by anthropogenic habitat degradation in the northern Adriatic Sea

Shallow coastal seas play an important role in the economy of many countries by sustaining fisheries, tourism, aquaculture and other economic activities. Their exploitation has large-scale ecosystem effects that are easily overlooked, as they often built up over decades or centuries, and historical ecological reference data are rarely available. Here, we assess these effects by comparing live and surface death assemblages (recording historical community states) of soft-bottom molluscs across a range of habitats in the northern Adriatic Sea, using the degree of mismatch between the 2 assemblages as a proxy for ecological change. We found a consistent live-dead mismatch at all stations. Although the degree of mismatch varied between stations with low and high time-averaging (i.e. the range of post-mortem shell ages), the community change followed the same trend over the entire Adriatic basin regardless of the type of sedimentary environment, with a loss of epifaunal species and the reduction of grazers, carnivores, and herbivores. In turn, the abundance of infaunal and opportunistic species feeding on plankton or detritus strongly increased in the living communities. Directionality and magnitude of these changes cannot be explained by time-averaging or by differences in species durability, but reflect a true ecological shift in response to multiple, long-lasting anthropogenic pressures, mainly bottom trawling, eutrophication and hypoxia. The original heterogeneous assemblages characteristic of different sedimentary habitats are thus replaced by a more infaunal, functionally impoverished and less diverse benthic community representing a new ecological baseline shaped by human impact.

Up in the air: Threats to Afromontane biodiversity from climate change and habitat loss revealed by genetic monitoring of the Ethiopian Highlands bat.

While climate change is recognized as a major future threat to biodiversity, most species are currently threatened by extensive human‐induced habitat loss, fragmentation and degradation. Tropical high‐altitude alpine and montane forest ecosystems and their biodiversity are particularly sensitive to temperature increases under climate change, but they are also subject to accelerated pressures from land conversion and degradation due to a growing human population. We studied the combined effects of anthropogenic land‐use change, past and future climate changes and mountain range isolation on the endemic Ethiopian Highlands long‐eared bat, Plecotus balensis, an understudied bat that is restricted to the remnant natural high‐altitude Afroalpine and Afromontane habitats. We integrated ecological niche modelling, landscape genetics and model‐based inference to assess the genetic, geographic and demographic impacts of past and recent environmental changes. We show that mountain range isolation and historic climates shaped population structure and patterns of genetic variation, but recent anthropogenic land‐use change and habitat degradation are associated with a severe population decline and loss of genetic diversity. Models predict that the suitable niche of this bat has been progressively shrinking since the last glaciation period. This study highlights threats to Afroalpine and Afromontane biodiversity, squeezed to higher altitudes under climate change while losing genetic diversity and suffering population declines due to anthropogenic land‐use change. We conclude that the conservation of tropical montane biodiversity requires a holistic approach, using genetic, ecological and geographic information to understand the effects of environmental changes across temporal scales and simultaneously addressing the impacts of multiple threats.

A Field-Based Adaptation of the Classic Morris Water Maze to Assess Learning and Memory in a Free-Living Animal

Free-living animals rely on cognitive functions, such as learning and memory, for numerous aspects of their survival. However, research involving these mechanisms is often limited to the laboratory where animals are far removed from natural influences. Here, we adapted the Morris Water Maze (MWM) for use in the field to test learning and memory of free-living white-footed mice, Peromyscus leucopus. The MWM consists of a pool filled with opaque water and a platform that is hidden beneath the surface of the water. Mice were tasked with finding an escape platform using proximate-cue based spatial learning skills across trials within and between two tests. The two tests occurred 2 hrs apart and each consisted of 5 trials with a maximum search time of 60 s, separated by 15-s breaks. We found mice demonstrated rapid learning within the first 5 trials, as indicated by a faster time and reduced distanced swam to find the platform in trial 5 as compared to trial 1 in Test 1. We also found mice remembered the task, as indicated by equivalent performance (in time and distance) after the two-hour delay period (i.e., performance in Test 2 trial 1 was similar to that in Test 1 trial 5). Lastly, we found that there was no increase in performance as mice completed an additional 5 trials (i.e., no difference in Test 1 trial 5 vs. Test 2 trial 5). By assessing several variables that serve as standard metrics for learning and memory within the MWM, we were able to illustrate the ability of wild mice to successfully navigate within a modified version of an established learning/memory paradigm. This study is important for promoting more accessible forms of cognitive testing in free-living animals and use of such a method could provide insights into how animals cope with environmental stressors in their natural environment such as anthropogenic disturbance, invasive species, and habitat degradation. A better understanding of cognitive behavior in wild animals may help diminish the disparity of knowledge that is often present between laboratory and field research.

Differences in dietary specialization, habitat use and susceptibility to human disturbance influence feeding rates and resource partitioning between two migratory Numenius curlew species

Migratory shorebirds select stopover sites to fuel their migration across heterogeneous coastal landscapes with abundant prey resources. Quantifying the degree of dietary specialization between closely-related species and how they partition resources across different coastal habitat types during both spring and autumn migration could identify some interesting possibilities for conservation management given the extent of anthropogenic habitat degradation at critical stopover sites. Here we used a comparative approach to examine diet specialization and feeding rates of two migratory Numenius curlew species, Far Eastern Curlew Numenius madagascariensis and Eurasian Curlew N. arquata populations, at an important stopover site in the Yellow Sea, China, and to assess the influence of habitat type, presence of human disturbance (activities related to aquaculture and oil production), and migratory season on their feeding behavior. Far Eastern Curlews were more dependent on tidal crabs and exhibited less dietary flexibility than its closely-related congener. Feeding rates on crabs by Far Eastern Curlews were not significantly different between mudflat and Suaeda salsa saltmarsh habitat but were negatively influenced by human disturbance and were higher during spring migration. In contrast, these effects were not apparent for Eurasian Curlew which fed predominantly on ragworms in saltmarsh habitat. The differences in prey type and feeding rates between adjacent habitats and migration seasons could explain how these two congeners fit syntopically along coastal wetland resource gradients. The extensive utilization of S. salsa habitat by both species suggests that saltmarshes represent an important feeding habitat for these species and that further conservation efforts aimed at reducing human disturbance would benefit both species and may lead to improved feeding rates for Far Eastern Curlews.

Long‐term monitoring reveals decreasing water beetle diversity, loss of specialists and community shifts over the past 28 years

Abstract Lentic freshwater organisms are influenced by a multitude of factors, including geomorphology, hydrology, anthropogenic impacts and climate change. Organisms that depend on patchy resources such as water beetles may also be sensitive to anthropogenic habitat degradation, like pollution, eutrophication, water level or management alteration. To assess composition and ecological trends in the water beetle communities of Central Europe, we sampled water beetles (Dytiscidae, Haliplidae, Noteridae) in 33 water bodies in Southern Germany from 1991 to 2018. We used manual, time‐standardised capture during three periods: between 1991 and 1995, 2007 and 2008, and 2017 and 2018. During the 28‐year survey period, we captured a total of 81 species. We found annual declines in both species number (ca −1%) and abundance (ca −2%). Also, community composition showed significant changes over time. The significant impact of pH on the community composition suggests that the recorded changes through time partly reflect natural succession processes. However, a pronounced decline of beetle species belonging to the moor‐related beetle associations indicated that Central European water beetles are also threatened by non‐successional factors, including desiccation, increased nitrogen input and/or mineralisation, and the loss of specific habitats. This trend to physiographical homogenisation resulted in corresponding community composition shifts. To effectively protect endangered species, conservation strategies need to be aimed at regularly creating new water bodies with mineralic bottom substratum, and maintenance of moor water bodies that represent late successional stages.

<p class="HeadingRunIn"><strong>Long-term macrobenthic community structure changes in the Upper Sakarya River System (1995–2015)</strong></p>

The Upper Sakarya River System (USRS) is one of the most important river systems in Turkey. Its primary drainage is provided by the Porsuk Seydi and Bardakçı Rivers and their tributaries. Long term benthic invertebrate community structure in the USRS was investigated from 1995–2015 (with sampling conducted every five years) in order to assess changes in their composition and in relation to water quality. Oligochaete specimens sorted from samples were identified to the species level when possible; all other invertebrate specimens sorted from samples were identified to order and family level. In addition, some environmental parameters (e.g., dissolved oxygen, temperature, and hydrogen ion concentration as pH) were measured in situ. Although Ephemeroptera-Plecoptera-Trichoptera fauna were the most abundant group in fauna of USRS during the years 1995, 2000 and (in part) 2005 (18.80, 17.69, and 14.07%, respectively), this ratio decreased to 7.90% during the more recent years of monitoring. In 1995, 2000 and 2005, Nais bretscheri, Chaetogaster diastrophus, Chaetogaster langi, Pristinella jenkinae, Aulodrilus pigueti, Aulodrilus pluriseta, Potamothrix hammoniensis, and Psammoryctides albicola were the dominant oligochaete taxa. After 2005, tubificine species became more prevalent in samples. While 6 stations had high BMWP (Biological Monitoring Working Party) value in 1995, 2000 and 2005, only 1 station had high value after 2005. Values of Shannon Diversity Indices ranged from 2.00 to 3.05 for the years 1995–2000, 1.87 to 2.24 for the years 2000–2005, 1.06 to 1.85 for the years 2005–2010, and 0.97 to 1.80 for the years 2010–2015. In USRS, while values of dissolved oxygen were measured as 8.00 mg/l and 9.00 mg/l in 1995 and 2000, this high value was measured only at one station in 2015. It was found that numerical and proportional distributions of benthic invertebrates in the USRS have changed considerably between 1995 and 2015. It is obvious that these changes are the result of anthropogenic habitat degradation.

Impacts of Habitat Degradation on Tropical Montane Biodiversity and Ecosystem Services: A Systematic Map for Identifying Future Research Priorities

Tropical montane forests (TMFs) are major centres of evolutionary change and harbour many endemic species with small geographic ranges. In this systematic map, we focus on the impacts of anthropogenic habitat degradation on TMFs globally. We first determine how TMF research is distributed across geographic regions, degradation type (i.e. deforestation, land-use conversion, habitat fragmentation, ecological level (i.e. ecosystem, community, population, genetic) and taxonomic group. Secondly, we summarize the impacts of habitat degradation on biodiversity and ecosystem services, and identify deficiencies in current knowledge. We show that habitat degradation in TMFs impacts biodiversity at all ecological levels and will be compounded by climate change. However, despite montane species being perceived as more extinction-prone due to their restricted geographic ranges, there are some indications of biotic resilience if the impacts to TMFs are less severe. Species richness and key species interactions can be maintained in mildly degraded sites, and gene flow can persist between TMF fragments. As such, minimally degraded areas such as secondary forests and restored areas could play a crucial role in maintaining the meta-community and ecosystem services of TMFs - either via resource provision or by linking patches of pristine forest. Research deficiencies highlighted include poor research representation in Asian and African TMFs, few assessments of population and genetic-level responses to fragmentation, and little assessment of the impacts of habitat fragmentation at all ecological levels. To address these concerns, we present a list of the top research priorities to urgently address the growing threat of habitat degradation in TMF.