TY  - JOUR
A1  - Ghasemi, Marziye
A1  - Latifi, Hooman
A1  - Pourhashemi, Mehdi
T1  - A novel method for detecting and delineating coppice trees in UAV images to monitor tree decline
JF  - Remote Sensing
N2  - Monitoring tree decline in arid and semi-arid zones requires methods that can provide up-to-date and accurate information on the health status of the trees at single-tree and sample plot levels. Unmanned Aerial Vehicles (UAVs) are considered as cost-effective and efficient tools to study tree structure and health at small scale, on which detecting and delineating tree crowns is the first step to extracting varied subsequent information. However, one of the major challenges in broadleaved tree cover is still detecting and delineating tree crowns in images. The frequent dominance of coppice structure in degraded semi-arid vegetation exacerbates this problem. Here, we present a new method based on edge detection for delineating tree crowns based on the features of oak trees in semi-arid coppice structures. The decline severity in individual stands can be analyzed by extracting relevant information such as texture from the crown area. Although the method presented in this study is not fully automated, it returned high performances including an F-score = 0.91. Associating the texture indices calculated in the canopy area with the phenotypic decline index suggested higher correlations of the GLCM texture indices with tree decline at the tree level and hence a high potential to be used for subsequent remote-sensing-assisted tree decline studies.
KW  - UAV
KW  - crown delineation
KW  - coppice
KW  - Zagros oak forests
KW  - edge detection
KW  - decline
KW  - texture analysis
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-297258
SN  - 2072-4292
VL  - 14
IS  - 23
ER  - 
TY  - JOUR
A1  - Kleijn, David
A1  - Winfree, Rachael
A1  - Bartomeus, Ignasi
A1  - Carvalheiro, Luísa G.
A1  - Henry, Mickael
A1  - Isaacs, Rufus
A1  - Klein, Alexandra-Maria
A1  - Kremen, Claire
A1  - M'Gonigle, Leithen K.
A1  - Rader, Romina
A1  - Ricketts, Taylor H.
A1  - Williams, Neal M.
A1  - Adamson, Nancy Lee
A1  - Ascher, John S.
A1  - Báldi, András
A1  - Batáry, Péter
A1  - Benjamin, Faye
A1  - Biesmeijer, Jacobus C.
A1  - Blitzer, Eleanor J.
A1  - Bommarco, Riccardo
A1  - Brand, Mariette R.
A1  - Bretagnolle, Vincent
A1  - Button, Lindsey
A1  - Cariveau, Daniel P.
A1  - Chifflet, Rémy
A1  - Colville, Jonathan F.
A1  - Danforth, Bryan N.
A1  - Elle, Elizabeth
A1  - Garratt, Michael P. D.
A1  - Herzog, Felix
A1  - Holzschuh, Andrea
A1  - Howlett, Brad G.
A1  - Jauker, Frank
A1  - Jha, Shalene
A1  - Knop, Eva
A1  - Krewenka, Kristin M.
A1  - Le Féon, Violette
A1  - Mandelik, Yael
A1  - May, Emily A.
A1  - Park, Mia G.
A1  - Pisanty, Gideon
A1  - Reemer, Menno
A1  - Riedinger, Verena
A1  - Rollin, Orianne
A1  - Rundlöf, Maj
A1  - Sardiñas, Hillary S.
A1  - Scheper, Jeroen
A1  - Sciligo, Amber R.
A1  - Smith, Henrik G.
A1  - Steffan-Dewenter, Ingolf
A1  - Thorp, Robbin
A1  - Tscharntke, Teja
A1  - Verhulst, Jort
A1  - Viana, Blandina F.
A1  - Vaissière, Bernard E.
A1  - Veldtman, Ruan
A1  - Ward, Kimiora L.
A1  - Westphal, Catrin
A1  - Potts, Simon G.
T1  - Delivery of crop pollination services is an insufficient argument for wild pollinator conservation
JF  - Nature Communications
N2  - There is compelling evidence that more diverse ecosystems deliver greater benefits to people, and these ecosystem services have become a key argument for biodiversity conservation. However, it is unclear how much biodiversity is needed to deliver ecosystem services in a cost- effective way. Here we show that, while the contribution of wild bees to crop production is significant, service delivery is restricted to a limited subset of all known bee species. Across crops, years and biogeographical regions, crop-visiting wild bee communities are dominated by a small number of common species, and threatened species are rarely observed on crops. Dominant crop pollinators persist under agricultural expansion and many are easily enhanced by simple conservation measures, suggesting that cost- effective management strategies to promote crop pollination should target a different set of species than management strategies to promote threatened bees. Conserving the biological diversity of bees therefore requires more than just ecosystem-service-based arguments.
KW  - ecosystem services
KW  - european countries
KW  - abundance
KW  - native bees
KW  - biodiversity conservation
KW  - plant diversity
KW  - fruit set
KW  - productivity
KW  - decline
KW  - pollen
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-151879
VL  - 6
IS  - 7414
ER  -